vv ^ ^ 
 
 '^^'^7 
 
 mmm. 
 
 ^"y. 
 
 
 "^■^ ^^^■ 
 
 Sf. 
 
 '■ ^ i ^ 
 
 
 -'>'> ^^A-r^iA 
 
 
 
 
 'V 'i" 
 
 

 \«^/?/^^ ■■':^ 
 
 "f^Vi'WAi^^-a^^lj 
 

 ■!m^'-:m((<^ 
 
 
 
 
;l-:^Yo^v 
 
The Modern Clock 
 
 A Study of Time Keeping Mechanism; 
 
 Its Construction, Regulation 
 
 and Repair. 
 
 BY WARD L. GOODRICH 
 
 Author of the Watchmaker's Lathe, Its Use and Abuse, 
 
 BOSTON COLLEGE LIBRaKY 
 OHJC8TNUT HILL, MASS. 
 
 WITH NUMEROUS ILLUSTRATIONS AND DIAGRAMS 
 
 CHICAGO 
 Hazlitt 8c Walker, Publishers 
 1905 
 
.^^n 
 
 Copyrighted 
 
 1905 
 
 BY HAZI.ITT & WALKER. 
 
CHAPTER I. 
 
 THE NECESSITY FOR BETTER SKILL AMONG CLOCKMAKERS 
 
 The need for information of an exact and reliable char- 
 acter in regard to the hard worked and much abused clock 
 has, we presume, been felt by every one who entered the 
 trade. This information exists, of course, but it is scat- 
 tered through such a wide range of pubHcations and is found 
 in them in such a fragmentary form that by th^ time a 
 workman is sufficiently acquainted with the literature of the 
 trade to know where to look for such information he no 
 longer feels the necessity of acquiring it. 
 
 The continuous decrease in the prices of watches and the 
 consequent rapid increase in their use has caused the neglect 
 of the pendulum timekeepers to such an extent that good 
 clock men are very scarce, while botches are universal. 
 When we reflect that the average "life' of a v/orker at the 
 bench is rarely mere than twenty years, we can readily see 
 that information by verbal instruction is rapidly being lost, 
 as each apprentice rushes through clock work as hastily as 
 possible in order to do watch work and consequently each 
 "watchmaker" knows less of clocks than his predecessor 
 and is therefore less fitted to instruct apprentices in his 
 turn. 
 
 The striking clock will always continue to be the time- 
 keeper of the household and we are still dependent upon the 
 compensating pendulum, in conjunction with the fixed stars, 
 for the basis of our time-keeping system, upon which our 
 commeicial and legal calendars and the movements of our 
 ships and railroad trains depend, so that an accurate knowl- 
 edge of its construction and behavior forms the essential 
 
 3. •.■ ..-..-:' 
 
4. THE MDDERN CEOCK. 
 
 basis of the largest part of our business and social system?, 
 while the watches for which it is slighted are themselves 
 regulated , and adjusted at the factories by the compensated 
 pendulum. 
 
 The rapid increase in the dissemination of "standard 
 time"*' and the com.pulsory use of watches having a maxi- 
 mum variation of five seconds a week by railway employes 
 has so increased the standard of accuracy dem.anded by the 
 general public that it is no longer possible to make careless 
 work "go" with them, and, if they accept it at all, they 
 are apt to make serious deductions from their estimate of 
 the watchmaker's skill and immediately transfer their cus- 
 tom to some one who is more thorough. 
 
 The apprentice, when he first gets an opportunity to ex- 
 amine a clock movement, usually considers it a very myste- 
 rious machine. Later on, if he handles many clocks of the 
 simple order, he becomes tolerably familiar with the time 
 train ; but he seldorn becomes confident of his ability regard- 
 ing the striking part, the alarm and the escapement, chiefly 
 because the employer and the older workmen get tired of 
 telling him the same things repeatedly, or because they were 
 similarly treated in their youth, and consider clocks a nui- 
 sance, any how, never having learned clock work thorough- 
 ly, and therefore being unable to appreciate it. In conse- 
 quence of such treatment the boy makes a few spasmodic 
 efforts to learn the portions of the business that puzzle him, 
 and then gives it up, and thereafter does as little as possible 
 to clocks, but begs continually to be put on watch work. 
 
 We know of a shop where two and sometimes three 
 workmen (the best in the shop, too) are constantly employed 
 upon clocks which country jewelers have failed to repair. 
 If clock work is dull they will go upon watch work (and 
 they do good work, too), but they enjoy the clocks and will 
 do them in preference to watches, claiming that there is 
 greater variety and more interest in the work than can be 
 found in fitting factory made material into watches, which 
 
TPIE MODERN CLOCK. 5 
 
 consist of a time train only. Two of these men have be- 
 come famous, and are frequently sent for to take care of 
 complicated clocks, with musical and mechanical figure at- 
 tachments, tower, chimes, etc. The third is much younger, 
 but is rapidly perfecting himself, and is already competent 
 to rebuild minute repeaters and other sorts of the finer 
 kinds of French clocks. He now totally neglects watch 
 work, saying that the clocks give him mort money and 
 more fun. 
 
 We are confident that this would be also the case with 
 many another American youth if he could find some one 
 to patiently instruct him in the few indispensable facts which 
 lie at the bottom, of so much that is mysterious and from 
 which he now turns in disgust. The object of these arti- 
 cles is to explain to the apprentice the mysteries of pendu- 
 lums, escapements, gearing of trains, and the whole tech- 
 nical scheme of these measurers of time, in such a way that 
 hereafter he may be able to answer his own questions, be- 
 cause he will be familiar with the facts on which they 
 depend. 
 
 Many workmen in the trade are already incompetent to 
 teach clockwork to anybody, owing to the slighting process 
 above referred to ; and the frequent demands for a book on 
 clocks have therefore induced the writer to undertake its 
 compilation. Works on the subject — nominally so, at least 
 — are in existence, but it will generally be found on exami- 
 nation that they are written by outsiders, not by workmen, 
 and that they treat the subject historically, or from the 
 standpoint of the artistic or the curious. Any information 
 regarding the mechanical movements is fragm.entary, if 
 found in them at all, and they are better fitted for the amuse- 
 ment of the general public than for the youth or man who 
 wants to know "how and why." These facts have im- 
 pelled the writer to ignore history and art in considering 
 the subject; to treat the clock as an existing mechanism 
 which must be understood and made to perform its func- 
 
THE MODERN CLOCK. 
 
 tions correctly ; and to consider cases merely as housings 
 of mechanism, regardless of how beautiful, strange or com- 
 monplace those housings may be. 
 
 We have used the word "compile" advisedly. The writer 
 has no new ideas or theories to put forth, for the reason 
 that the mechanism we are considering has during the last 
 six hundred years had its mathematics reduced to an exact 
 science; its variable factors of material and mechanical 
 movements developed according to the laws of geometry and 
 trigonometry ; its defects observed and pointed out ; its per- 
 formances checked and recorded. To gather these facts, 
 illustrate and explain them, arrange them in their proper 
 order, and point out their relative importance in the whole 
 sum of what we call a clock, is therefore all that will be at- 
 tempted. In doing this free use has been made of the ob- 
 servations of Saunier, Reid, Glasgow, Ferguson, Britten, 
 Riefler and others in Europe and of Jerome, Playtner, Finn, 
 Learned, Ferson, Howard and various other Americans. 
 The work is therefore presented as a compilation, which it 
 is hoped will be of service in the trade. 
 
 In thus studying the modern American clocks, we use the 
 word American in the sense of ownership rather than origin, 
 the clocks which come to the American workmen to-day 
 have been made in Germany, France, England and America. 
 
 The German clocks are generally those of the Schwartz- 
 wald (or Black Forest) district, and differ from others in 
 their structure, chiefly in the following particulars: The 
 movement is supported by a horizontal seat-board in the 
 upper portion of the case. The wooden trains of many of 
 the older type instead of being supported by plates are held 
 in position by pillars, and these pillars are held in position 
 by top and bottom boards. In the better class of wooden 
 clocks the pivot holes in the pillars are bushed with brass 
 tubing, while the movement has a brass *scape wheel, steel 
 wire pivots and lantern pinions of wood, with steel trun- 
 
THE MODERN CLOCK. 7 
 
 dies. In all these clocks the front pillars are friction tight, 
 and are the ones to be removed when taking down the 
 trains. Both these and the modern Swartzwald brass move- 
 ments use a sprocket wheel and chain for the weights and 
 have exposed pendulums and weights. 
 
 The French clocks are of two classes, pendules and car- 
 riage clocks, and both are liable to develop more hidden 
 crankiness and apparently causeless refusals to go than, 
 ever occurred to all the English, German and American 
 clocks ever put together. There are many causes for this^ 
 and unless a mxan is very new at the business he can tell 
 stories of perversity, that w^ould make a timid apprentice 
 want to quit. Yet the French clocks, when they do go, are 
 excellent time-keepers, finely finished, and so artistically de- 
 signed that they make their neighbors seem very clumsy by 
 comparison. They are found in great variety, time, half- 
 hour and quarter-hour strike, musical and repeating clocks 
 being a few of the general varieties. The pendulums are 
 very short, to accommodate themselves to the artistic needs 
 of the cases, and nearly all have the snail strike instead of 
 the count wheel. The carriage clocks have v/atch escape- 
 ments of cylinder or lever form, and the escapement is fre- 
 quently turned at right angle by means of bevel gears, or 
 contrate wheel and pinion, and placed on top of the move- 
 ment. 
 
 The English clocks found in America are generally of 
 the ''Hall" variety, having heavy, well finished movements, 
 with seconds pendulum and frequently with calendar and 
 chime movements. They, like the German, are generally 
 fitted with weights instead of springs. There are a few 
 English carriage clocks, fitted with springs and fuzees, 
 though most of them, like the French, have springs fitted in 
 going barrels. 
 
 The American clocks, with which the apprentice will nat- 
 urally have most to do, may be roughly divided into time. 
 
8 THE MODERN CLOCK. 
 
 time alarm, tim.e strike, time strike alarm, time calendar 
 and electric winding. The American factories generally 
 each make about forty sizes and styles of movements, and 
 case them in many hundreds of different ways, so that the 
 workman will frequently find the same movement in a large 
 number of clocks, and he will soon be able to determine from 
 the characteristics of the movement what factory made the 
 clock, and thus be able to at once turn to the proper cata- 
 logue if the name of the maker be erased, as frequently 
 happens. 
 
 This comparative study of the practice of different facto- 
 ries will prove very interesting, as the movement comes to 
 the student after a period of prolonged and generally se- 
 vere use, which is calculated to bring out any existing de- 
 fects in construction or workmanship ; and having all makes 
 of clocks constantly passing through his hands, each ex- 
 hibiting a characteristic defect more frequently than any 
 other, he is in a much better position to ascertain the merits 
 and defects of each maker than he v/ould be in any factory. 
 
 Having thus briefly outlined the kinds of machinery used 
 in measuring time, we will now turn our attention to the 
 examination of the theoretical and mechanical construction 
 of the various parts. 
 
 The man who starts out to design and build a clock will 
 find himself limited - in three particulars : It must run a 
 specified time; the arbor carrying the minute hand must 
 turn once in each hour ;. the pendulum must be short enough 
 to go in the case. Two of these particulars are changeable 
 according to circumstances ; the length of time run may be 
 thirty hours, eight, thirty, sixty or ninety days. The pendu- 
 lum may be anywhere from four inches to fourteen feet, and 
 the shorter it is the faster it will go. The one definite 
 point in the time train is that the minute hand must turn 
 once in each hour. We build or alter our train from this 
 point both ways, back through changeable intermediate 
 
THE MODERN CLOCK. 
 
 wheels and pinions to the spring or weight forming the 
 source of power, and forward from it through another 
 changeable series of wheels and pinions to the pendulum. 
 Now as the pendulum governs the rate of the clock we will 
 commence with that and consider it independently. 
 
CHAPTER II. 
 
 ' THE NATURAL LAWS GOVERNING PENDULUMS. 
 
 Length of Pendulum. — A pendulum is a falling body 
 and as such is subject to the laws which govern falling bod- 
 ies. This statement may not be clear at first, as the pendu' 
 lum generally moves through such a small arc that it does 
 not appear to be falling. Yet if we take a pendulum and 
 raise the ball by swinging it up tmtil the ball is level with the 
 point of suspension, as in Fig. i, and then let it go, we 
 
 f 1 . 
 
 /' N 
 
 s-^ ^A 
 
 \J 
 
 1 i 
 1 1 
 
 1 
 
 I 1 
 
 1 
 
 \ 1 
 
 1 
 
 \ 1 
 
 1 
 
 \ , 
 
 1 
 
 \ ! 
 
 I 
 
 \ 1 
 
 N I 
 \ 1 
 
 / 
 
 • 
 
 % ' 
 
 / 
 
 s 1 
 
 • 
 
 ««. / ^ 
 
 ^ ^ 
 
 >* . II 
 
 -^ 
 
 - --^..<1- 
 
 ^-^ 
 
 Fig. 1. Dotted lines show path of pendulum. 
 
 shall see it fall rapidly until it reaches its lowest point, and 
 then rise until it exhausts the momentum it acquired in fall- 
 ing, when it will again fall and rise again on the other side ; 
 this process will be repeated through constantly smaller 
 arcs until the resistance of the air and that of the pendulum 
 spring shall overcome the other forces which operate to 
 keep it in motion and it finally assumes a position of rest 
 at the lowest point (nearest the earth) which the pendulum 
 
 ID 
 
THE MODERN CLOCK. II 
 
 rod will allow it to assume. When it stops, it will be in 
 line between the center of the earth (center of gravity) 
 and the fixed point from which it is suspended. True, the 
 pendulum bob, when it falls, falls under control of the 
 pendulum rod and has its actions modified by the rod ; but 
 it falls just the same, no matter how small its arc of motion 
 may be, and it is this influence of gravity — that force which 
 makes any free body move toward the earth's center — 
 which keeps the pendulum constantly returning to its low- 
 est point and which governs very largely the time taken in 
 moving. Hence, in estimating the length of a pendulum, 
 we must consider gravity as being the prime mover of our 
 pendulum. 
 
 The next forces to consider are mass and weight, which, 
 when put in motion, tend to continue that motion indefinitely 
 unless brought to rest by other forces opposing it. This is 
 known as momentum. A heavy bob will swing longer 
 than a light one, because the momentum stored up during 
 its fall will be greater in proportion to the resistance which 
 it encounters from the air and the suspension spring. 
 
 As the length of the rod governs the distance through 
 which our bob is allowed to fall, and also controls the direc- 
 tion of its motion, we must consider this motion. Refer- 
 ring again to Fig. i, we see that the bob moves along the 
 circumference of a circle, with the rod acting as the radius 
 of that circle ; this opens up another series of facts. The 
 circumference of a circle equals 3.1416 times its diameter, 
 and the radius is half the diameter (the radius in this case 
 being the pendulum rod). The areas of circles are propor- 
 tional to the squares of their diameters and the circumfer- 
 ences are also proportional to their areas. Hence, the 
 lengths of the paths of bobs moving along these circumfer- 
 ences are in proportion to the squares of the lengths of the 
 pendulum rods. This is why -a pendulum of half the length 
 will oscillate four times as fast. 
 
 Now we will apply these figures to our pendulum. A 
 
12 THE MODERN CLOCK. 
 
 body falling in vacuo, in London, moves 32.2 feet in one 
 second. This distance Kas by common consent among 
 mathematicians been designated as g. The circumference 
 of a circle equals 3.416 times its diameter. This is repre- 
 sented as 77- Now, if we call the time t, we shall have the 
 formula : 
 
 'Vi 
 
 ^ 
 
 Substituting the time, one second, for t, and doing the same 
 with the others, we shall. have: 
 
 CJ2.2 ft. r ^ r 
 
 I = — ^^= c>.26i6 feet. 
 
 (3.i4i6)» ^ 
 
 Turning this into its equivalent in inches by multi- 
 plying by 12, we shall have 39.1393 inches as the length of 
 a one-second pendulum at London. 
 
 Now, as the force of gravity varies somewhat with its 
 distance from the center of the earth, we shall find the value 
 of g in the above formula varying slightly, and this will 
 give us slightly different lengths of pendulum at different 
 places. These values have been found to be as follows : 
 
 Inches. 
 
 The Equator is 3g 
 
 Rio dc Janiero 39-01 
 
 Madras 3(;'.02 
 
 New York , 39. 10x2 
 
 Paris 39.13 
 
 London 39-14 
 
 Edinbv.rsh 39.15 
 
 Greenland 39-20 
 
 North and South Pole 39.206 
 
 Now, taking another look at our formula, we shall see 
 that we may get the length of any pendulum by multiply- 
 n^^TT (which is 3.1416) by the square of the time required: 
 To find the length of a pendulum to beat three seconds : 
 
 3' = 9- 39-1393x9 = 352.2537 inches = 29.3544 feet. 
 A pendulum beating two-thirds of a second, or 90 beats: 
 
THE MODERN CLOCK. I3 
 
 (2). ^ 4. . 39-1393 X 4 ^ 17.3953 inches. 
 A pendulum beating half-seconds or 120 beats : 
 (,^,^,. 39-.393X. ^^_^3^S inches. 
 
 Center of Oscillation. — Having now briefly consid- 
 ered the basing facts governing the time of oscillation of 
 the pendulum, let us examine it still further. The pendu- 
 lum shown in Fig. i has all its weight in a mass at its end, 
 but we cannot make a pendulum that way to run a clock, 
 because of physical limitations. We shall have to use a 
 rod stiff enough to transmit power from the clock move- 
 ment to the pendulum bob and that rod will weigh some- 
 thing. If we use a compensated rod, so as to keep it the 
 same length in varying temperature, it may weigh a good 
 deal in proportion to the bob. How will this affect the pen- 
 dulum ? 
 
 If we suspend a rod from its upper end and place along- 
 side of it our ideal pendulum, as in Fig. 2, we shall find that 
 they will not vibrate in equal times if they are of equal 
 lengths. Why not? Because when the rod is swinging 
 (being stiff) a part of its weight rests upon the fixed point 
 of suspension and that part of the rod is consequently not 
 entirely subject to the force of gravity. Now, as the time 
 in which our pendulum will swing depends upon the dis- 
 tance of the effective center of its mass from the point of 
 suspension, and as, owing to the difference in construction, 
 the center of mass of one of our pendulums is at the center 
 of its ball, while that of the other is somewhere along the 
 rod, they will naturally swing in different times. 
 
 Our other pendulum (the rod) is of the same size all the 
 way up and the center of its effective mass would be the 
 center of its weight (gravity) if it were not for the fact 
 which we stated a moment ago that part of the weight is 
 upheld and rendered ineft'ective by the fixed support of the 
 
H 
 
 THE MODERN CLOCK. 
 
 f-A- 
 
 6 
 
 A^ 
 
 
 
 a 
 
 Fig. 2. Two pendulums of equal length but unequal vibration. B, cen- 
 ter of oscillation for both pendulums. 
 
 y ^ 
 • y 
 
 y y 
 
 y y 
 
 ?s 
 
 Fig. 3. 
 
THE MODERN CLOCK. 
 
 ^5 
 
 pendulum rod, all the while the pendulum is not in a vertical 
 position. If we support the rod in a horizontal position^ as 
 in Fig. 3, by holding up the lower end, the point of sus- 
 pension, A, will support half the weight of the rod ; if we 
 hold it at 45 degrees the point of suspension will hold less 
 than half the weight of the rod and more of the rod will 
 be affected by gravity; and so on down until we reach the 
 vertical or up and down position. Thus we see that the 
 force of. gravity pulling on our pendulum varies in its ef- 
 fects according to the position of the rod and consequently 
 the effective center of its mass also varies with its position 
 and we can only calculate what this mean (or average) po- 
 sition is by a long series of calculations and then taking an 
 average of these results. 
 
 We shall find it simpler to measure the time of swing of 
 the rod which we will do by shortening our ball and cord 
 until it will swing in the same time as the rod. This will be 
 at about two-thirds of the length of the rod, so that the 
 effective length of our rod is about two-thirds of its real 
 length. This effective length, which governs the time of 
 vibration, is called the theoretical length of the pendulum 
 and the point at which it is located is called its center of 
 oscillation. The distance from the center of oscillation to 
 the point of suspension is called the theoretical length of the 
 pendulum and is always the distance which is given in all 
 tables of lengths of pendulums. This length is the one 
 given for two reasons : First, because, it is the time-keeping 
 length, which is what we are after, and second, because, as 
 we have just seen in Fig. 3, the real length of the pendulum 
 increases as more of the weight of the instrument is put into 
 the rod. This explains why the heavy gridiron compensa- 
 tion pendulum beating seconds so common in regulators and 
 which measures from. 56 to 60 inches over all, beats in the 
 same time as the wood rod and lead bob measuring 45 
 inches over all, while one is apparently a third longer than 
 the other. 
 
i6 
 
 THE MODERN CLOCK. 
 
 Table Showing the Length of a Simple Pendulum 
 
 That performs in one hour any given number of oscillations, from r 
 to 20,000, and the variation in this length that will occasion a difference 
 of I minute in 24 hours. 
 
 Calculated by E. Gourdin. 
 
 of 
 rHolir. 
 
 S2 
 
 Pi 
 
 p 
 
 -■ 
 
 ^ s 
 
 u 
 
 „• 
 
 Length 
 te in 24 
 meters. 
 
 .1 
 
 
 1^1 
 
 1' 
 
 B 
 
 u 
 
 
 it 
 
 %\ 
 
 ;5s 
 
 H 
 
 l.sl 
 
 0. -^ 
 
 -:M 
 
 '^ 
 
 ♦-1 r:: 
 
 2 « S 
 
 3 -s 
 
 y^ .-3 
 
 .2 «- 
 
 3 Z! 
 
 A .t: 
 
 2«.S 
 
 
 S 
 
 ih 
 
 % J 
 
 ^ 
 
 % 
 
 |oi 
 
 y-< 3. 
 
 % 
 
 |o| 
 
 
 
 
 M 
 
 
 cS u 
 
 m 
 
 
 ^ Ki 
 
 
 
 
 >.°s ■ 
 
 
 
 
 >^S 
 
 
 
 
 >ex 
 
 20,000 
 
 32.2 
 
 G.04 
 
 13,200 
 
 73.9 
 
 0.10 
 
 8,200 
 
 191.5 
 
 0.26 
 
 19,000 
 
 35.7 
 
 0.05 
 
 13,100 
 
 75.1 
 
 0.10 
 
 8,100 
 
 196.3 
 
 0.27 
 
 18,000 
 
 39.8 
 
 0.05 
 
 13,000 
 
 76.2 
 
 0.10 
 
 8,000 
 
 201.3 
 
 o.2r 
 
 17,900 
 
 40.2 
 
 0.06 
 
 12,900 
 
 77.4 
 
 0.11 
 
 7,900 
 
 206.4 
 
 0.28 
 
 17,800 
 
 40.7 
 
 0.06 
 
 12,800 
 
 78.6 
 
 0.11 
 
 7,800 
 
 211.7 
 
 0.29 
 
 17,700 
 
 41.1 
 
 0.06 
 
 12,700 
 
 79.9 
 
 0.11 
 
 7,700 
 
 217.3 
 
 0.30 
 
 17.fi00 
 
 41.6 
 
 0.06 
 
 12,600 
 
 81.1 
 
 0.11 
 
 7,600 
 
 223.0 
 
 0.3<> 
 
 17.500 
 
 42.1 
 
 0.06 
 
 12,5110 
 
 82.4 
 
 0.11 
 
 7,500 
 
 229.0 
 
 0.31 
 
 17,400 
 
 42.4 
 
 0.06 
 
 12,400 
 
 83.8 
 
 0.11 
 
 7,400 
 
 235.2 
 
 0.3* 
 
 17,300 
 
 43.0 
 
 0.06 
 
 12,300 
 
 85.1 
 
 0.12 
 
 7,300 
 
 241.7 
 
 0.3* 
 
 17,200 
 
 43.5 
 
 0.06 
 
 12,200 
 
 86.5 
 
 0.12 
 
 7,200 
 
 248.5 
 
 0.34 
 
 17.100 
 
 44.0 
 
 0.06 
 
 12,100 
 
 88.0 
 
 0.12 
 
 7,100 
 
 255.7 
 
 0.3* 
 
 17,000 
 
 44.6 
 
 0.06 
 
 12,000 
 
 89.5 
 
 0.12 
 
 7,000 
 
 262.9 
 
 0.3& 
 
 16,900 
 
 45.1 
 
 0.06 
 
 11,900 
 
 91.0 
 
 0.12 
 
 6,900 
 
 270.5 
 
 o.sr 
 
 16,800 
 
 45.7 
 
 0.06 
 
 11,800 
 
 92.5 
 
 0.13 
 
 6,800 
 
 278.6 
 
 0.3» 
 
 16,700 
 
 46.3 
 
 0.06 
 
 11,700 
 
 94.1 
 
 0.13 
 
 6,700 
 
 286.9 
 
 0.S» 
 
 16.600 
 
 46.7 
 
 0.07 
 
 11,600 
 
 95.7 
 
 0.13 
 
 6,600 
 
 295.7 
 
 0.40 
 
 16,500 
 
 47.3 
 
 0.07 
 
 11,500 
 
 97.4 
 
 0.13 
 
 6,500 
 
 304.9 
 
 0.41 
 
 16,400 
 
 47.9 
 
 0.07 
 
 11,400 
 
 99.1 
 
 0.13 
 
 6,400 
 
 314.5 
 
 0.4* 
 
 16,300 
 
 48.5 
 
 0.07 
 
 11,300 
 
 100.9 
 
 0.14 
 
 6,300 
 
 324.5 
 
 0.44 
 
 16,200 
 
 49.1 
 
 0.07 
 
 11,2U0 
 
 102.7 
 
 0.14 
 
 6,200 
 
 335.1 
 
 0.46 
 
 16,100 
 
 49.7 
 
 0.07 
 
 11,100 
 
 104.5 
 
 0.14 
 
 6,100 
 
 34R.2 
 
 o.4r 
 
 16,0<iO 
 
 50.0 
 
 0.07 
 
 11,000 
 
 106.5 
 
 0.14 
 
 6,C00 
 
 357.8 
 
 0.4* 
 
 15,900 
 
 51.0 
 
 0.07 
 
 10,900 
 
 108.4 
 
 0.15 
 
 5,900 
 
 370.0 
 
 0.50 
 
 15,800 
 
 51.6 
 
 0.07 
 
 10,800 
 
 110.5 
 
 0.15 
 
 5,800 
 
 382.9 
 
 0.5* 
 
 15,7ti0 
 
 52.3 
 
 0.07 
 
 10,700 
 
 112.5 
 
 0.15 
 
 5,700 
 
 396.4 
 
 0.54 
 
 15.600 
 
 52.9 
 
 0.07 
 
 10,600 
 
 114.6 
 
 0.16 
 
 5,600 
 
 410.7 
 
 0.50 
 
 15,500 
 
 53.6 
 
 0.07 
 
 10,500 
 
 116.8 
 
 0.16 
 
 5,500 
 
 425.^ 
 
 0.58^ 
 
 15,400 
 
 54.3 
 
 0.08 
 
 10,400 
 
 119.1 
 
 0.16 
 
 5,400 
 
 440.1 
 
 0.6O 
 
 15,300 
 
 55.0 
 
 0.08 
 
 11,300 
 
 111.4 
 
 0.17 
 
 5,300 
 
 458.5 
 
 0.6* 
 
 15,200 
 
 55.7 
 
 0.08 
 
 10,200 
 
 123.8 
 
 0.17 
 
 5,200 
 
 476.3 
 
 0.6S 
 
 15,100 
 
 56.5 
 
 0.08 
 
 10,100 
 
 126.3 
 
 0.17 
 
 5,100 
 
 495.2 
 
 o.er 
 
 15,000 
 
 57.3 
 
 0.08 
 
 10,000 
 
 128.8 
 
 0.18 
 
 5,000 
 
 515.2 
 
 0.70 
 
 14,900 
 
 58.0 
 
 0.08 
 
 9,900 
 
 131.4 
 
 0.18 
 
 4,900 
 
 536.5 
 
 0.7* 
 
 14,800 
 
 58.8 
 
 0.08 
 
 9,800 
 
 134.1 
 
 0.18 
 
 4,800 
 
 559.1 
 
 0.78 
 
 14,700 
 
 59.6 
 
 0.08 
 
 9,700 
 
 136.9 
 
 0-19 
 
 4,700 
 
 583.1 
 
 0.70 
 
 14,600 
 
 60.4 
 
 0.08 
 
 9,600 
 
 139.8 
 
 0.19 
 
 4,600 
 
 • 608.7 
 
 O.Si 
 
 14,500 
 
 61.3 
 
 0.08 
 
 9,500 
 
 142.7 
 
 0.19 
 
 4,500 
 
 636.1 
 
 0.8R 
 
 14,400 
 
 68.1 
 
 0.09 
 
 9,400 
 
 145.8 
 
 0.20 
 
 4,400 
 
 665.3 
 
 0.90 
 
 141300 
 
 63.0 
 
 0.09 
 
 9,300 
 
 148.9 
 
 0-20 
 
 4,300 
 
 696.7 
 
 0.9S 
 
 14,200 
 
 63.9 
 
 0.09 
 
 9,200 
 
 152.2 
 
 0.21 
 
 4,200 
 
 730.2 
 
 0.90 
 
 14,100 
 
 64.8 
 
 0.09 
 
 9,100 
 
 155.5 
 
 0-21 
 
 4,100 
 
 766.2 
 
 1.04 
 
 14,000 
 
 65.7 
 
 0.09 
 
 9,noo 
 
 159.0 
 
 0.22 
 
 4,000 
 
 805.0 
 
 1.00 
 
 13,900 
 
 66.7 
 
 0.09 
 
 8,900 
 
 162.6 
 
 0.22 
 
 3,950 
 
 825.5 
 
 1.1* 
 
 13,800 
 
 67.6 
 
 0.09 
 
 8,800 
 
 IK6.3 
 
 0.23 
 
 3,900 
 
 846.8 
 
 1.15 
 
 13.700 
 
 68-6 
 
 0.(19 
 
 8,700 
 
 170.2 
 
 0.2:3 
 
 3,850 
 
 869.0 
 
 l.ld 
 
 13,600 
 
 69.6 
 
 0.09 
 
 8,600 
 
 173.7 
 
 0.24 
 
 S,800 
 
 892.0 
 
 1.21 
 
 13,500 
 
 70.7 
 
 0.09 
 
 8,500 
 
 178.3 
 
 0.24 
 
 3,750 
 
 915.9 
 
 1.2s 
 
 13,400 
 
 71.7 
 
 0.10 
 
 8,400 
 
 182.5 
 
 0.25 
 
 3,700 
 
 940.1 
 
 L28 
 
 13,300 
 
 72.8 
 
 0.10 
 
 8,300 
 
 187.0 
 
 0.25 
 
 3,650 
 
 966.8 
 
 1.31 
 
THE MODERN CLOCK. 
 
 Table of the Length of a Simple Pendulum, 
 
 (continued.) 
 
 CO 
 
 § 
 
 ■J 
 
 j2 
 
 To Produce in 
 24 Hours 
 
 1 
 
 
 To Produce 
 
 in 24 Hours 
 
 i: 
 
 
 1 Minute. 
 
 % 
 
 
 1 M 
 
 nute. 
 
 1 3 
 
 
 
 u 
 
 Length 
 in 
 
 
 
 2« 
 
 ^i 
 
 t^t 
 
 
 
 <= i 
 
 si 
 
 ^%% 
 
 A^ 
 
 '° 'z 
 
 Meters. 
 
 Loss, 
 
 Gain, 
 
 ^ " 
 
 n 
 
 o| S 
 
 %r^ 
 
 1 "- 
 
 
 Lengthen by 
 
 Shorten by 
 
 a 
 
 3 
 
 :a 
 
 
 
 E 
 
 3 
 
 - 
 
 Meters. 
 
 Meters. 
 
 "A 
 
 
 ^^ 
 
 C/3S 
 
 ^ 
 
 
 
 
 3 600 
 
 0.9939 
 
 1.38 
 
 1.32 
 
 1900 
 
 3.5G8 
 
 0.0950 
 
 0.0048 
 
 3,550 
 
 1.0221 
 
 1,42 
 
 1.36 
 
 1,800 
 
 3 975 
 
 0055 
 
 0.0053 
 
 3,500 
 
 1.0515 
 
 1.46 
 
 1.40 
 
 1,700 
 
 4.457 
 
 0.0062 
 
 -0.0059 
 
 3,450 
 
 1.0822 
 
 1.50 
 
 144 
 
 1;600 
 
 5.031 
 
 0070: 
 
 0.00(^7 
 
 3.400 
 
 1.1143 
 
 1.55 
 
 1.48 
 
 1,500 
 
 5 725 
 
 0.01^80 
 
 0.0076 
 
 3,350 
 
 1.1477 
 
 1.60 
 
 1.53 
 
 1,400 
 
 6.572 
 
 0.0091 
 
 0.0087 
 
 3,300 
 
 1.1828 
 
 1.64 
 
 1.57 
 
 1,300 
 
 7.6-22 
 
 0.0106 
 
 0.0101 
 
 3.250 
 
 1.2194 
 
 1.69 
 
 1.62 
 
 1,200 
 
 8.945 
 
 0124 
 
 0.0119 
 
 3,200 
 
 1.2578 
 
 175 
 
 1.67 
 
 1,100 
 
 10.645 
 
 0.0148 
 
 0.0142 
 
 3,150 
 
 1.2981 
 
 1.80 
 
 1.73 
 
 1,000 
 
 12.880 
 
 0.0179 
 
 0.0171 
 
 3,100 
 
 1.3403 
 
 1.86 
 
 178 
 
 900 
 
 15 902 
 
 0.0221 
 
 0.0211 
 
 3,050 
 
 1.3846 
 
 1.93 
 
 1.84 
 
 800 
 
 20.126 
 
 0280 
 
 0.0268 
 
 3,U00 
 
 1.4312 
 
 1.99 
 
 190 
 
 700 
 
 26.287 
 
 0365 
 
 0.0350 
 
 2.900 
 
 1.5316 
 
 2.13 
 
 2.04 
 
 600 
 
 35 779 
 
 00497 
 
 0.0476 
 
 2.800 
 
 1.6429 
 
 2.28 
 
 218 
 
 500 
 
 51 521 
 
 0.0716 
 
 0.0685 
 
 2.700 
 
 1.7669 
 
 2.46 
 
 2 35 
 
 400 
 
 SO 502 
 
 0.1119 
 
 0.1071 
 
 2,600 
 
 19054 
 
 2.65 
 
 2 53 
 
 30© 
 
 143115 
 
 0.1989 
 
 0.1903 
 
 2,500 
 
 2.0609 
 
 2 87 
 
 2.74 
 
 200 
 
 322 008 
 
 0.4476 
 
 0.4282 
 
 2,400 
 
 2.2362 
 
 3.11 
 
 297 
 
 100 
 
 1,283.034 
 
 1.7904 
 
 1.7131 
 
 2,800 
 
 2.4349 
 
 3.38 
 
 3 24 
 
 60 
 
 3,577.871 
 
 4 9732 
 
 4.7586 
 
 2,200 
 
 2 6612 
 
 3.70 
 
 8.54 
 
 50 
 
 5,152.135 
 
 7.1613 
 
 6.8521 
 
 2,100 
 
 2.9207 
 
 4.06 
 
 3 88 
 
 1 
 
 12,880,337.930 
 
 17,9036700 
 
 17,130.8500 
 
 2,000 
 
 32201 
 
 4.48 
 
 4.28 
 
 
 
 
 
 In the foregoing tables all dimensions are given in meters 
 and millimeters. If it is desirable to express them in feet 
 and inches, the necessary conversion can be at once effected 
 in any given case by employing the following conversion 
 table, which will prove of considerable value to the watch- 
 maker for various purposes : 
 
Ii THE MODERN CLOCK. 
 
 Conversioa Table of Inches, Millimeters and French Lines. 
 
 Inches expressed in 
 
 MUlimeters 
 
 expressed 
 
 French Lines expressed 
 
 Millimeters and French 
 
 in Inches and French 
 
 in Inches and 
 
 Lines. 
 
 Lines. 
 
 Millimeters. 
 
 i 
 
 Equal to 
 
 1 
 
 Equal to 
 
 
 Equal to 
 
 u 
 
 
 
 
 
 
 ^ 
 
 
 
 M 
 
 Millimeters 
 
 French 
 Lines. 
 
 S 
 
 Inches. 
 
 French 
 Lines. 
 
 fa 
 
 Inches. 
 
 Millimeters 
 
 1 
 
 25 39954 
 
 11.25951 
 
 1 
 
 0.0393708 
 
 0.44329 
 
 1 
 
 0.088414 
 
 2.25583 
 
 ^ 
 
 50.79908 
 
 22.51903 
 
 2 
 
 0.0787416 
 
 0.88659 
 
 2 
 8 
 
 0.177628 
 0266441 
 
 4.51166 
 6.76749 
 
 3 
 
 76.19862 
 
 33.77854 
 
 3 
 
 0.1181124 
 
 1.32989 
 
 4 
 
 0.355255 
 
 9.02332 
 
 4 
 
 101.59816 
 
 45.03806 
 
 4 
 
 0.1574832 
 
 1.77318 
 
 5 
 
 0.444069 
 
 11.27915 
 
 5 
 
 126.99771 
 
 56.29757 
 
 5 
 
 0.1968539 
 
 2.21648 
 
 6 
 
 0.532883 
 
 13.53497 
 
 6 
 
 162.39725 
 
 67.55709 
 
 6 
 
 0.2362247 
 
 2.65978 
 
 7 
 
 0.621697 
 
 15.79080 
 
 7 
 
 177.79679 
 
 78 81660 
 
 7 
 
 0.2755955 
 
 3.10307 
 
 8 
 9 
 
 0.710510 
 0.799324 
 
 18.04663 
 20.30246 
 
 8 
 
 203 19633 
 
 90.07612 
 
 8 
 
 0.3149664 
 
 3.54637 
 
 10 
 
 0.888138 
 
 22.55829 
 
 9 
 
 22859587 
 
 10133563 
 
 9 
 
 0.3543371 
 
 3 98966 
 
 11 
 
 0.976952 
 
 2481412 
 
 10 
 
 253.99541 
 
 112.59515 
 
 10 
 
 0.3937079 
 
 4.43296 
 
 12 
 
 1.065766 27.06995 
 
 Center of Gravity. — The watchmaker is concerned only 
 with the theoretical or timekeeping lengths of pendulums, 
 as his pendulum comes to him ready for use; but the clock 
 maker who has to build the pendulum to fit not only the 
 movement, but also the case, needs to know more about it, 
 as he must so distribute the weight along its length thai it 
 may be given a length of 6o inches or of 44 inches, or any- 
 thing between them, and still beat seconds, in the case of a 
 regulator. He must also do the same thing in other clocks 
 having pendulums which beat other numbers than 60. 
 Therefore he must know the center of his weights ; this is 
 called the center of gravity. This center of gravity is often 
 
THE MODERN CLOCK. 
 
 19 
 
 confused by many with the center of oscillation as its real 
 purpose is not understood. It is simply used as a starting 
 point in building pendulums, because there must be a start- 
 ing point, and this point is chosen because it is always pres- 
 ent in every pendulum and it is convenient to work both 
 ways from the center of weight or gravity. In Fig. 2 we 
 have two pendulums, in one of which (the ball and string) 
 the center of gravity is the center of the ball and the center 
 of oscillation is also at the center (practically) of the ball. 
 Such a pendulum is about as short as it can be constructed 
 for any given number of oscillations. The other (the rod) 
 has its center of gravity manifestly at the center of the rod, 
 as the rod is of the same size throughout ; yet we found by 
 comparison with the other that its center of oscillation was 
 at two-thirds the length of the rod, measured from the point 
 of suspension, and the real length of the pendulum was con- 
 sequently one-half longer than its time keeping length, which 
 is at the center of oscillation. This is farther apart than 
 the center of gravity and oscillation will ever get in actual 
 practice, the most extreme distance in practice being that 
 of the gridiron pendulum previously mentioned. The cen- 
 ter of gravity of a pendulum is found at that point at which 
 the pendulum can be balanced horizontally on a knife edge 
 and is marked to measure from when cutting off the rod. 
 
 The center of oscillation of a compound pendulum must 
 always be below its center of gravity an amount depending 
 upon the proportions of weight between the rod and the bob. 
 Where the rod is kept as light as it should be in proportion 
 to the bob this difference should come well within the lim- 
 its of the adjusting screw. In an ordinary plain seconds 
 pendulum, without compensation, with a bob of eighteen 
 or twenty pounds and a rod of six ounces, the difference in 
 the two points is of no practical account, and adjustments 
 for seconds are within the screw of any ordinary pendulum, 
 if the screw is the right length for safety, and the adjusting 
 nut is placed in the middle of the length of the screw threads 
 
20 THE MODERN CLOCK. 
 
 when the top of the rod is cut off, to place the suspen- 
 sion spring by measurement from the center of gravity as 
 has been already described ; also a zinc and iron compensa- 
 tion is within range of the screw if the compensating rods 
 are not made in undue weight to the bob. The whole 
 v/eight of the compensating parts of a pendulum can be 
 safely made within one and a half pounds or lighter, and 
 carry a bob of twenty-five pounds or over without buckling 
 the rods, and the two points, the center of gravity and the 
 center of oscillation, will be within the range of the screw. 
 There are still some other forces to be considered as af- 
 fecting the performance of our pendulum. These are the 
 resistance to its momentum offered by the air and the resist- 
 ance of the suspension spring. 
 
 Barometric Error. — If we adjust a pendulum in a clock 
 with an airtight case so that the pendulum swings a certain 
 number of degrees of arc, as noted on the degree plate in 
 the case at the foot of the pendulum, and then start to pump 
 out the air from the case while the clock is running, we shall 
 find the pendulum swinging over longer arcs as the air be- 
 comes less until we reach as perfect a vacuuni as we can 
 produce. If we note this point and slowly admit air to the 
 case again we shall find that the arcs of the pendulum's 
 swing will -he slowly shortened until the pressure in the 
 case equals that of the surrounding air, when they will be 
 the same as when our experiment was started. If we now 
 pump air into our clock case, the vibrations will become 
 still shorter as the pressure of the air increases, proving con- 
 clusively that the resistance of the air has an effect on the 
 swinging of the pendulum. 
 
 We are accustomed to measure the pressure of the air as 
 it changes in varying weather by 'means of the barometer 
 and hence we call the changes in the swing of the pendulum 
 due to varying air pressure the ^'barometric error." The 
 barometric error of pendulums is only considered in the 
 
THE MODERN CLOCK. 21 
 
 very finest of clocks for astronomical observatories, master 
 clocks for watch factories, etc., hut the resistance of the air 
 is closely considered v^hen we come to shape our bob. This 
 is why bobs are either double-convex or cylindrical in shape, 
 as these two forms offer the least resistance to the air and 
 (which is more important) they offer equal resistance on 
 both sides of the center of the bob and thus tend to keep 
 the pendulum, swinging in a straight line back and forth. 
 
 The Circular Error. — As the pendulum swings over a 
 greater arc it will occupy more time in doing it and thus 
 the rate of the clock will be affected, if the barometric 
 changes are very great. This is called the circular error. 
 In ancient times, when it was customary to make pendulums 
 vibrate at least fifteen degrees, this error was of importance 
 
 Fig. 4. A, arc of circle. B, cycloid path of pendulum, exaggerated. 
 
 and clock makers tried to make the bob take a cycloidal 
 path, as is shown in Fig. 4, greatly exaggerated. This was 
 accomplished by suspending the pendulum by a cord which 
 swung between cycloidal cheeks, but it created so much fric- 
 tion that it was abandoned in favor of the spring as used 
 to-day. It has since been proved that the long and short 
 arcs of the pendulum's vibration are practically isochronous 
 (with a spring of proper length and thickness) up to about 
 six degrees of arc (three degrees each side of zero on the 
 degree plate at the foot of the pendulum) and hence small 
 variations of power in spring-operated clocks and also the 
 barometric error are taken care of, except for greatly in- 
 creased variations of power, or for too great arcs of vibra- 
 tion. Here we see the reasons for and the amount of swing 
 v»re can properly give to our pendulum. 
 
22 THE MODERN CLOCK. 
 
 Temperature Error. — The temperature error is the 
 greatest which we shall have to consider. It is this which 
 makes the compound pendulum necessary for accurate time, 
 and we shall consequently give it a great amount of space, 
 as the methods of overcoming it should be fully understood. 
 
 Expansion of Metals. — The materials commonly used 
 in m.aking pendulums are wood (deal, pine and mahogany), 
 steel, cast iron, zinc, brass and mercury. Wood expands 
 .0004 of its length between 32°. and 212° F. ; lead, .0028; 
 steel, .0011; mercury, .0180; zinc, .0028; cast iron, .oori ; 
 brass, .0020. Now the length of a seconds pendulum, by 
 our tables (3600 beats per hour) is 0.9939 meter; if the rod 
 is brass it will lengthen .002 with such a range of tempera- 
 ture. As this is practically two-thousandths of a meter, this 
 is a gain of two millimeters, which would produce a varia- 
 tion of one minute and forty seconds every twenty-fouf 
 hours; consequently a brass rod would be a very bad one. 
 
 If we take two of these materials, with as wide a differ- 
 ence in expansion ratios as possible, and use the least 
 variable for the rod and the other for the bob, supporting it 
 at the bottom, we can make the expansion of the rod coun- 
 terbalance the expansion of the bob and thus keep the effec- 
 tive length of our pendulum constant, or nearly so. This is 
 the theory of the compensating pendulum. 
 
CHAPTER III. 
 
 COMPENSATING PENDULUMS. 
 
 As the pendulum is the means of regulating the time con- 
 sumed in unwinding the spring or weight cord by means 
 of the escapement, passing one tooth of the escape wheel 
 at each end of its swing, it will readily be seen that length- 
 ening or shortening the pendulum constitutes the means of 
 regulating the clock; this would make the whole subject a 
 very simple affair, were it not that the reverse proposition 
 is also true ; viz. ; Changing the length of the pendulum 
 will change the rate of the clock and after a proper rate has 
 been obtained further changes are extremely undesirable. 
 This is what makes the temperature error spoken of in the 
 preceding chapter so vexatious where close timing is de- 
 sired and why as a rule, a well compensated pendulum costs 
 more than the rest of the clock. The sole reason for the 
 business existence "of watch and clockmakers lies in the 
 necessity of measuring time, and the accuracy with which 
 it may be done decides in large measure the value of any 
 watchmaker in his community. Hence it is of the utmost 
 importance that he shall provide himself with an accurate 
 means of measuring time, as all his work must be judged 
 finally by it, not only while he is working upon time-meas- 
 uring devices, but also after they have passed into the pos- 
 session of the general public. 
 
 A good clock is one of the very necessary foundation 
 elements, contributing very largely to equip the skilled me- 
 chanic and verify his work. Without some reliable means 
 to get accurate mean time a watchmaker is always at sea — 
 without a compass — and has to trust to his faith and a 
 
 23 
 
24 THE MODERN CLOCK. 
 
 large amount of guessing, and this is always an embarrass- 
 ment, no matter how skilled he may be in his craft, or adept 
 in guessing. What I want to call particular attention to is 
 the unreliable and worthless character of the average regu- 
 lator of the present day. A good clock is not necessarily a 
 high' priced instrument and it is within the reach of most 
 watchmakers. A thoroughly good and reliable timekeeper 
 of American make is to be had now in the market for less 
 than one hundred dollars, and the only serious charge that 
 can be made against these clocks is that they cost the con- 
 sumer too much money. Any of them are thirty-three and 
 a third per cent higher than they should be. About seventy- 
 five dollars will furnish a thoroughly good clock. The aver- 
 age clock to be met with in the watchmakers' shops is the 
 Swiss imitation • gridiron pendulum, pin escapement, and 
 these are of the low grades as a rule; the best grades of 
 them rarely ever get into the American market. Almost 
 without exception, the Swiss regulator, as described, is 
 wholly worthless as a standard, as the pendulums are only 
 an imitation of the real compensated pendulum. Tkey are 
 an imitation all through, the bob being hollow and filled 
 with scrap iron, and the brass and steel rods composing the 
 compensating element, along with the cross pieces or bind- 
 ers, are all of the cheapest and poorest description. If one 
 of these pendulums was taken away from the movement 
 and a plain iron bob and wooden rod put to the movement, 
 in its place, the possessor of any such clock would be sur- 
 prised to find how m*uch better average rate the clock would 
 have the year through, although there would then be no 
 compensating mechanisrh, or its semblance, in the make up 
 of the pendulum. In brief, the average imitation compen- 
 sation pendulum of this particular variety is far poorer 
 than the simplest plain pendulum, such as the old style, 
 grandfather clocks were equipped with. A wood rod would 
 be far superior to a steel one, or any metal rod, as may be 
 seen bv consulting the expansion data given in the previous 
 chapter 
 
THE MODERN CLOCK. 
 
 ^5 
 
 Many other pendulums that are sold as compensating 
 are a delusion in part, as they do not thoroughly compen- 
 sate, because the elements composing them are not in 
 equilibrium or in due proportion to one another and to the 
 general mechanism. 
 
 To all workmen who have a Swiss regulator, I would 
 say that the movement, if put into good condition, will an- 
 swer very well to niaintain the motion of a good pendulum, 
 and that it will pay to overhaul these movements and put 
 to them good pendulums that will pretty nearly compen- 
 sate. At least a well constructed pendulum will give a 
 very useful and reliable rate with such a motor, and be a 
 great help and satisfaction to any man repairing and rating 
 good watches. 
 
 The facts are, that one of the good grade of American 
 adjusted watch movements will keep a much steadier rate 
 when maintained in one position than the average regulator. 
 Without a reliable standard to regulate by, there is very 
 little satisfaction in handling a good movement and then not 
 be able to ascertain its capabilities as to rate. Very many 
 watch carriers are better up in the capabilities of good 
 watches than many of our American repairers are, because 
 a large per cent of such persons have bought a watch of 
 high grade with a published rate, and naturally when it is 
 made to appear to entirely lack a constant rate when com- 
 pared with the average regulator, they draw the conclusion 
 that the clock is at fault, or that the cleaning and repairing 
 are. Many a fair workman has lost his watch trade, largely 
 on account of a lack of any kind of reliable standard of 
 time in his establishment. There, are very few things that 
 a repairer can do in the way of advertising and holding his 
 customers more than to keep a good clock, and furnish 
 good watch owners a means of comparison and thus to con- 
 firm their good opinions of their watches. 
 
 We have along our railroads throughout the country a 
 standard time system of synchronized clocks, which are an 
 
26 THE MODERN CLOCK. 
 
 improvement over no standard of comparison; but they 
 cannot be depended upon as a reliable standard, because 
 they are subject to all the uncertainties that affect the tele- 
 graph lines^ — bad service, lack of skill, storms, etc. The 
 clocks furnished by these systems are not reliable in them- 
 selves and they are therefore corrected once in twenty-four 
 hours by telegraph, being automatically set to mean time by 
 the mechanism for that purpose, which is operated by a 
 standard or master clock at some designated point in the 
 system. 
 
 Now all this is good in a general way ; but as a means to 
 regulate a fine watch and use as a standard from day to 
 day, it is not adequate. A standard clock, to be thoroughly 
 serviceable, must always, all through the twenty-four hours, 
 have its seconds hand at the correct point at each minute 
 and hour, or it is unreliable as a standard. The reason is 
 that owing to train defects watches may vary back and 
 forth and these errors cannot be detected with a standard 
 that is right but once a day. No man can compare to a 
 certainty unless his standard is without variation, substan- 
 tially ; and I do not know of any way that this can be ob- 
 tained so well and satisfactorily as through the means of 
 a thoroughly good pendulum. 
 
 Compensating seconds pendulums are, it might be said, 
 the standard time measure. Mechanically such a pendulum 
 is not in any way difficult of execution, yet by far the 
 greater portion of pendulums beating seconds are not at all 
 accurate time measures, as independently of their slight 
 variations in length, any defects in the construction or fit- 
 ting of their parts are bound to have a direct effect upon 
 the performance of the clock. The average watchmaker 
 as a mechanic has the ability to do the work properly, but 
 he does not fully understand or realize what is necessary, 
 nor appreciate the fact that little things not attended to 
 will render useless all his efforts. 
 
 The first consideration in a compensated pendulum is to 
 
THE MODERN CLOCK. 27 
 
 maintain the center of oscillation at a fixed distance from 
 the point of suspension and it does not matter how this is 
 accomplished. 
 
 So, also, the details of construction are of little conse- 
 quence, so long as the main points are well looked after — 
 the perfect solidity of all parts, with very few of them, and 
 the free movement of all working surfaces without play, so 
 that the compensating action may be constantly maintained 
 at all times. Where this is not the case the sticking, rat- 
 tling, binding or cramping of certain parts will give differ- 
 ent rates at different times under the same variations of 
 temperature, according as the parts work smoothly and 
 evenly or move only by jerks. 
 
 The necessary and useful parts of a pendulum are all that 
 are really admissible in thoroughly good construction. Any 
 and all pieces attached by way of ornament merely are apt 
 to act to the prejudice of the necessary parts and should 
 be avoided. In this chapter we shall give measurements 
 and details of construction for a number of compensated 
 pendulums of various kinds, as that will be the best means 
 of arriving at a thorough understanding of the subject, 
 even if the reader does not desire to construct such a pen- 
 dulum for his own use. 
 
 Principles of Construction. — Compensation pendu- 
 lums are constructed upon two distinct principles. First, 
 those in which the bob is supported by the bottom, resting 
 on the adjusting screw with its entire height free to expand 
 upward as the rod expands downward from its fixed point 
 of suspension. In this class of pendulums the error of the 
 bob is used to counteract that of the rod and if the bob is 
 made of sufficiently expansible metal it only remains to 
 make the bob of sufficient height in proportion to its ex- 
 pansibility for one error to offset the other. In the second 
 class the attempt is made to leave out of consideration any 
 errors caused by expansion of the bob, by suspending it 
 
28 THE MODERN GLQCK. 
 
 from the center, so that its expansion downward will ex- 
 actly balance its expansion upward, and hence they will bal- 
 ance each other and may be neglected. Having, eliminated 
 the bob from consideration by this m^ans we must neces- 
 sarily confine our attempt at compensation to the rod in the 
 second method. 
 
 The wood rod and lead bob and the mercurial pendulums 
 are examples of the first-class and the wood rod with brass 
 sleeve having a nut at the bottom and reaching to the center 
 of the iron bob and the common gridiron, or compound 
 tubular rod, or compound bar of steel and brass, or -steel 
 and zinc, are examples of the second class. 
 
 Wood Rod and Zinc Bob. — We will suppose that we 
 have one of the Swiss imitation gridiron pendulums which 
 we want to discard, while retaining the case and movement. 
 As these cases are wide and generally fitted with twelve- 
 inch dials, we shall have about twenty inches inside our case 
 and we may therefore use a large bob, lens-shaped,, made of 
 cast zinc, polished and lacquered to look like brass. 
 
 The bobs in such imitation gridiron pendulums are gener- 
 ally about thirteen inches in diameter and swing about five 
 inches (two and a half inches each side). The. pendulums 
 are generally light, convex in front and flattened at the 
 rear, and the entire pendulum measures about 56 inches 
 from the point of suspension to the lower end of the adjust- 
 ing screw. We will also suppose that we desire to change 
 the appearance of the clock as little as possible, while im- 
 proving its rate. This will mean that we desire to retain a 
 lens-shaped bob of about the same size as the one we are 
 going to remove. 
 
 We shall first need to know the total length of our pen- 
 dulum, so that we can calculate the expansion of the rod. 
 A seconds pendulum measures 39.2 inches from the point 
 in the suspension spring at the lower edge of the chops to 
 the center of oscillation. With a lens-shaped bob the center 
 
THE MODERN CLOCK. * '29 
 
 of gravity will be practically at the center of the bob, if we 
 use a light \vooden rod arid a steel adjusting screw and 
 brass nut, as these metal parts, although short, will be 
 heavy enough to nearly balance the suspension spring and 
 that portion of the rod which is above the center. We shall 
 also gain a little in balance if we leave the steel screw. long 
 enough to act as an index over the degree .plate, in the case, 
 at the bottom of the pendulum, by stripping the thread and 
 turning the end to a taper an inch or so in length. 
 
 We shall only be able to use one-half of the expansion 
 upwards of our bob, because the centers of gravity and os- 
 cillation will be practically together at the center of the bob. 
 We shall find the center of gravity easily by balancing the 
 pendulum on a knife-edge and thus we will be able to make 
 an exceedingly close guess at the center of oscillation. 
 
 Now, looking over our data, we find that we have a sus- 
 pension spring of steel, then some wood and steel again at 
 the other end. We shall need about one inch of suspension 
 spring. The spring will, of course, be longer than one 
 inch, but we shall hold it in iron chops and the expansion 
 of the chops will equal that of the spring between them, so 
 that only the free part of the spring need be considered. 
 Now from the adjusting screw, where it leaves the last 
 pin through the wood, to the middle position of the rating 
 nut will be about one inch, so we shall have two inches of 
 steel to consider in our figures of expansion. 
 
 Now to get the length of the rod. We want to keep our 
 bob about the size of the other, so we will try 14 inches 
 diameter, as half of this is an even number and makes easy 
 figuring in our trials. 39.2 inches, plus 7 (half the diameter 
 of the bob) gives us 46.2 inches; now we have an inch of 
 adjustment in our screw, so we can discard the .2; this 
 leaves us 46 inches of wood and steel for which we must 
 get the expansion. 
 
JO ♦ THE MODERN CLOCK. 
 
 Wood expands .0004 of its length between 32° and 212° F. 
 Steel expands .0011 of its length between 32° and 212° F. 
 Lead expands .0028 of its length between 32° and 212° F. 
 Brass expands .0020 of its length between 32** and 212" F. 
 Zinc expands .0028 of its length between 32** and 212° F. 
 Tin expands .0021 of its length between 32** and 212° F. 
 Antimony expands .0011 of its length between 32° and 212° F. 
 Total length of pendulum to adjusting nut 46 inches. 
 Total length of steel to adjusting nut 2 inches. 
 Total length of wood to adjusting nut 44 inches. 
 ,0011 X 2 = .0022 inch, expansion of our steel. 
 .0004 X 44:= .0176 inch, expansion of our wood. 
 
 .0198 total expansion of rod. 
 
 We have 7 inches as half the diameter of our bob 
 .0198 -^ 7 = .0028 2-y, which we find from our tables is 
 very close to the expansion of zinc, so we will make the bob 
 of that metal." Now let us check back ; the upward expan- 
 sion of 7 inches of zinc equals .0028 X .7 ^ .0196 inch, as 
 against .0198 inch downward expansion of the rod. This 
 gives us a total difference of .0002 inch between 32° and 
 212° or a range of 180° F. This is a difference of .0001 
 inch for 90° of temperature and is closer than most pendu- 
 lums ever get. 
 
 The above figures are for dry, clear white pine, well 
 baked and shellacked, with steel of average expansion, and 
 zinc of new metal, melted and cast without the admixtures 
 of other metals or the formation of oxide. The presence 
 of tin, lead, antimony and other admixtures in the zinc 
 would of course change the results secured; so also will 
 there be a slight difference in the expansion of the rod if 
 other woods are used. Still the jeweler can from the above 
 get a very close approximation. 
 
 Such a bob, 14 inches diameter and 1.5 inches thick, alike 
 on both sides, with an oval hole ix.5 inches through its cen- 
 ter, see Fig. 5, would weigh about 30 to 32 pounds, and 
 
THE MODERN CLOCK. 
 
 31 
 
 f 
 
 o , o 
 
 Tor 
 
 I 
 
 Fig. 5. Zinc bob and wood rod to replace imitation gridiron pendulum. 
 
32 
 
 THE MODERN CLOCK. 
 
 would have to be hung from a cast iron bracket, Fig. 6, 
 bolted through the clock case to the wall behind it, so as to 
 get a steady rate. It would be nearly constant, as the metal 
 is spread out so as to be quickly affected by temperature; 
 and the shape would hold it well in its plane of oscillation, 
 if both sides were of exactly the same curvature, while the 
 
 n 
 
 Fig. G. Cast iron bracket for lieavy pendulums and movements. 
 
 weight would overcome minor disturbances due to vibration 
 of the building. It would require a little heavier suspension 
 spring, in order to be isochronous in the long and short 
 arcs and this thickening of the spring would need the addi- 
 tion of from one and a half to two pounds rnore of driving 
 weight. 
 
 If so heavy a pendulum is deemed undesirable, the bob 
 would have to be made of cylindrical form, retaining the 
 height, as necessary to compensation, and varying the diam- 
 eter of the cylinder to suit the weight desired. 
 
 Wood Rod and Lead Bob. — The wood should be clear, 
 straight-grained and thoroughly dried, then given several 
 coats of shellac varnish, well baked on. It may be either 
 
THE MODERN CLOCK. 
 
 33 
 
 Fig. 7. "Wood rod and 
 lead bob. 
 
 Fig. 8. Bob of metal casing 
 filled with shot. 
 
34 THE MODERN CLOCK. 
 
 flat, oval or round in section, but is generally made round 
 because the brass cap at the upper end, the lining for the 
 crutch, and the ferrule for the adjusting screw at the lower 
 end may then be readily made from tubing. For pendu- 
 lums smaller than one second, the wood is generally hard, 
 as It gives a firmer attachment of the metal parts. 
 
 Inches. 
 
 Length, top of suspension spring to bottom of bob 44.S 
 
 Length to bottom of nut 45.25 
 
 Diameter of bob 2.0 
 
 Length of bob 10.5 
 
 V/eight of bob, 3 lbs. 
 
 Acting length of suspension spring i.o 
 
 Width of spring 45 
 
 Thickness .008 
 
 Diameterr of rod 5 
 
 The top of the rod should have a brass collar fixed on it 
 by riveting through the rod and it should extend down the 
 rod about three inches, so as to make a firm support for the 
 slit to receive the lower clip of the suspension spring. The 
 lower end should have a slit or a round hole drilled longi- 
 tudinally three inches up the rod to receive the upper end of 
 the adjusting screw and this should also fit snugly and be 
 well pinned or riveted in place. See Fig. 7. A piece of 
 thin brass tube about one inch in length is fitted over the 
 rod where the crutch works. 
 
 In casting zinc and lead bobs, especially those of lens- 
 shapes, the jeweler should not attempt to do the work him- 
 self, but should go to a pattern maker, explain carefully 
 just what is wanted and have a pattern made, as such pat- 
 terns must be larger than the casting in order to take care 
 of the shrinkage due to cooling the molten metal. It will 
 also be better to use an iron core, well coated with graphite 
 when casting, as the core can be made smooth throughout 
 and the exact shape of the pendulum rod, and there will 
 then be no work to be done on the hole when the casting 
 is made. The natural shrinkage of the metal on cooling 
 
THE MODERN CLOCK. 3^ 
 
 will free the core, which can be easily driven out when 
 the metal is cc5ld and it will then leave a smooth, well 
 shaped hole to which the rod can be fitted to work easily, 
 but without shake. Lens-shaped bobs, particularly, should 
 be cast flat, with register pins on the flask, so as to get both 
 sides central with the hole, and be cast with a deep riser 
 large enough to put considerable pressure of melted metal 
 on the casting until it is chilled, so as to get a sound cast- 
 ing ; it should be allowed to remain in the sand until thor- 
 oughly cold, for the same reason, as if cooled quickly the 
 bob will have internal stresses which are liable to adjust 
 themselves sometime after the pendulum is in the clock 
 and thus upset the rate until such interior disturbances have 
 ceased. Cylinders may be cast in a length of steel tubing, 
 using a round steel core and driven out when cold. 
 
 If using oval or flat rods of wood, the adjusting screw 
 should be flattened for about three inches at its upper end, 
 wide enough to conform to the width of the rod ; then saw 
 a slot in the center of the rod, wide and deep enough to just 
 fit the flattened part of the screw ; heat the screw and apply 
 shellac or lathe wax and press it firmly into the slot with 
 the center of the screw in line with the center of the rod; 
 after the wax is cold select a drill of the same size as the 
 rivet wire; drill and rivet snugly through the rod, smooth 
 everything carefully and the job is complete. 
 
 If by accident you have got the rod too small for the hole, 
 so that there is any play, give the- rod another coat of 
 shellac varnish and after drying thoroughly, sand paper it 
 down until it will fit properly. 
 
 Round rods may be treated in the same manner, but it is 
 usual to drill a round hole in such a rod to just fit the 
 wire, then insert and rivet as before after the wax is cold, 
 finishing with a ferrule or cap of brass at the end of the 
 rod. 
 
 The slot for the suspension spring is fitted to the upper 
 end of the rod in the same manner. 
 
36 THE MODERN CLOCK. 
 
 Pendulum with Shot. — Still another method of mak- 
 ing a compensating pendulum, which gives a lighter pendu- 
 lum, is to make a case of light brass or steel tubing of about 
 three inches diameter. Fig. 8, with a bottom and top of 
 equal weight, so as to keep the center of oscillation about 
 the center of gravity, for convenience in working. The bot- 
 tom may be turned to a close fit, and soldered, pinned, or 
 riveted into the tube. It is pierced at its center and another 
 tube of the same material as the outer tube, with an internal 
 diameter which closely fits the pendulum rod is soldered or 
 riveted into the center of the bottom, both bottom and top 
 being pierced for its admission and the other parts fitted as 
 previously described. 
 
 The length of the case or canister should be about 11.5 
 inches so as to give room for a column of shot of 10.5 
 inches (the normal compensating height for lead) and still 
 leave room for correction. Make a tubular case for the 
 driving weight also and then we have a flexible system. 
 If it is necessary to add or subtract weight to obtain the 
 proper arcs of oscillation of the pendulum, it can be readily 
 done by adding to or taking from the shot in the weight 
 case. 
 
 Fill the pendulum to 10.5 inches with ordinary sports- 
 men's shot and try it for rate. If it gains in heat and loses 
 in cold it is over-compensated and shot must be taken from 
 it. If it loses in heat and gains in cold it is under-com- 
 pensated and shot should be added. 
 
 The methods of calculation were given in full in describ- 
 ing the zinc pendulum and hence need not be repeated here,, 
 but attention should be called to ' the ' fact that there are 
 three materials here, wood, steel or brass and lead and each 
 should be figured separately so that the last two may just 
 counterbalance the first. If the case is made light through- 
 out the effect upon the center of oscillation will be inappre- 
 ciable as compared with that of the lead, but if made 
 heavier than need be, it will exert a marked influence, par« 
 
THE MODERN CLOCK. 
 
 37 
 
 ticularly if its highest portion (the cover) be heavy, as we 
 then have the effect of a shifting weight high up on the 
 pendulum rod. If made of thin steel throughout and nickel 
 plated, we shall have a light and handsome case for our 
 bob. If this is not practicable, or if the color of brass be 
 preferred, it may be made of that material. 
 
 The following table of weights will be of use in making 
 calculations for a pendulum or for clock weights. 
 
 "Weight of Lead, Zinc and Cast Iron Cylinders One Half Inch Long. 
 
 Diameter 
 
 Weight in Pounds 
 
 Diameter 
 in Inches 
 
 Weight in Pounds 
 
 in Inches. 
 
 Lead 
 
 Zinc 
 
 Iron 
 
 Lead 
 
 Zinc 
 
 Iron 
 
 .25 
 
 .020 
 
 .012 
 
 .012 
 
 3 25 
 
 3 400 
 
 2.098 
 
 2.156 
 
 .5 
 
 .080 
 
 .049 
 
 .050 
 
 3 5 
 
 3.944 
 
 2.434 
 
 2.491 
 
 .75 
 
 .180 
 
 .111 
 
 .114 
 
 3 75 
 
 4 51 
 
 2.783 
 
 2 865 
 
 1 
 
 .321 
 
 .198 
 
 .204 
 
 4 
 
 5149 
 
 3.177 
 
 3.265 
 
 1.25 
 
 .503 
 
 .310 
 
 .319 
 
 4 25 
 
 5 813 
 
 3.587 
 
 3 686 
 
 1.5 
 
 .724 
 
 .447 
 
 .459 
 
 4.5 
 
 6 619 
 
 3 922 
 
 4.134 
 
 1.75 
 
 .984 
 
 .607 
 
 .624 
 
 4.75 
 
 7 265 
 
 4 483 
 
 4.607 
 
 2. 
 
 1.287 
 
 .794 
 
 .816 
 
 5 
 
 8 048 
 
 4966 
 
 5.103 
 
 2 25 
 
 1630 
 
 1.005 
 
 1033 
 
 5.25 
 
 8 872 
 
 5.474 
 
 5.626 
 
 2.5 
 
 2.009 
 
 2 239 
 
 1274 
 
 5 5 
 
 9 737 
 
 6.008 
 
 5.175 
 
 2.75 
 
 2.434 
 
 1502 
 
 1544 
 
 5.75 
 
 10.643 
 
 6.567 
 
 6.749 
 
 3. 
 
 2.897 
 
 1788 
 
 1837 
 
 6 
 
 11.590 
 
 7.152 
 
 7.350 
 
 Example:— Required, the weight of a lead pendulum bob, 3 
 inches diameter, 9 inches long, which has a hole through it .75 inch 
 in diameter. The weight of a lead cylinder 3 inches diameter i.a the 
 table is 2 897, which multiplied by 9 (the length given)=26.07 lbs. 
 Then the weight in the table of a cylinder .75 inch diameter is .18 
 and .18X9 = 1.62 lbs. And 26.07 - 1.62=24.45. the weight required in 
 lbs. 
 
 Auxiliary Weights. — If for any reason our pendulum 
 does not turn out with a rating as calculated and we find 
 after getting it to time that it is over compensated, it is a 
 comparatively simple matter to turn off a portion from the 
 bottom of a solid bob. By doing this in very small por- 
 tions at a time and then testing carefully for heat and cold 
 every time any amount has been removed, we shall in the 
 
38 THE MODERN CLOCK. 
 
 course of a few weeks arrive at a close approximation to 
 compensation, at least as close as the ordinary standards 
 available to the jeweler will permit. This is a matter of 
 weeks, because if the pendulum is being rated by the stan- 
 dard time which is telegraphed over the country daily at 
 noon, the jeweler, as soon as he gets his pendulum nearly 
 right, will begin to discover variations in the noon signal of 
 from .2 to 5 seconds on successive days. Then it becorhes 
 a matter of averages and reasoning, thus: If the pendu- 
 lum beats to , time on the first, second, third, fifth and 
 seventh days, it follows that the signal w^as incorrect — slow 
 or fast— on the fourth and sixth days. 
 
 If the pendulum shows a gain of one second a week on 
 the majority of the days, the observation must be continued 
 without changing the pendulum for another week. If the 
 pendulum shows two seconds gain at the end of this 
 time, we have tw^o things to consider. Is the length right, 
 or is the pendulum not fully compensated? We cannot an- 
 swer the second query without a record of the temperature 
 variations during the period of observations. 
 
 To get the temperature record we shall require a set of 
 maximum and minimum thermometers in our clock case. 
 They consist of mercurial thermometer tubes on the ordi- 
 nary Fahrenheit scales, but with a marker of colored wood 
 or metal resting on the upper end of the column of mercury 
 in the tube. The tube is not hung vertically, but is placed 
 in an inclined position so that the mark will stay where it 
 is pushed by the column of mercury. Thus if the tem- 
 perature rises during the day to 84 degrees the mark in the 
 maximum thermometer will be found resting in the tube 
 at 84° whether the mercury is there when the reading is 
 taken or not. Similarly, if the temperature has dropped 
 during the night to 40°, the mark in the minimum ther- 
 mometer will be found at 40°, although the temperature 
 may be 70° w^hen the reading is taken. After reading, the 
 thermometers are shaken to bring the marks back to the top 
 
THE MODERN CLOCK. 
 
 39 
 
 of the column of mercury and the thermometers are then 
 restored to their positions, ready for another reading on the 
 following day. 
 
 These records should be set down on a sheet every day 
 at noon in columns giving date, rate, plus or minus, maxi- 
 mum, minimum, average temperature and remarks as to 
 regulation, etc., and with these data to guide us we shall be 
 in a position to determine whether to move the rating nut or 
 not. If the temperature has been fairly constant we can 
 get a closer rate by moving the nut and continuing the ob- 
 servations. If the temperature has been increasing steadily 
 and our pendulum has been gaining steadily it is probably 
 over-compensated and the bob should be shortened a trifle 
 and the observations renewed. 
 
 It is best to ''make haste slowly" in such a matter. First 
 bring the pendulum to time in a constant temperature ; that 
 will take care of its proper length. Then allow the tem- 
 perature to vary naturally and note the results. 
 
 If the pendulum is under-compensated, so that the bob is 
 too short to take care of the expansion of the rod, auxiliary 
 weights of zinc in the shape of washers (or short cylinders) 
 are placed between the bottom of the bob and the rating 
 nut. This of course makes necessary a new adjustment and 
 another course of observations all around, but it will readily 
 be seen that it places a length of expansible metal between 
 the nut and the center of oscillation and thus makes up for 
 the deficiency of expansion of the bob. Zinc is generally 
 chosen on account of its high rate of expansion, but brass, 
 aluminum and other metals are also used. It is best to use 
 one thick washer, rather than a number of thinner ones, as 
 it is important to keep the construction as solid at this point 
 as possible. 
 
 Top Weights. — After bringing the pendulum as close 
 as possible by the compensation and the rating nuts, astron- 
 omers and others requiring exact time get a trifle closer rat- 
 
40 THE MODERN CLOCK. 
 
 ing by the use of top weights. These are generally U- 
 shaped pieces of thin metal which are slipped on the rod 
 above the bob without stopping the pendulum. They raise 
 the center of oscillation by adding to the height of the bob 
 when they are put on, or lower it when they are removed, 
 but they are never resorted to until long after the pendulum 
 is closer to time than the jeweler can get with his limited 
 standards of comparison. They are mentioned here simply 
 that their use may be understood when they may be encoun- 
 tered in cleaning siderial clocks. 
 
 Mercurial pendulums also belong to the class of com- 
 pensation by expansion of the bobs, but they are so numer- 
 ous and so different that they will be considered separately, 
 later on. 
 
 Compensated Pendulum Rods. — We will now consider 
 the second class, that in which an attempt is made to obtain 
 a pendulum rod of unvarying length. 
 
 The oldest form of compensated rod is undoubtedly the 
 gridiron of either nine, five or three rods. As originally 
 made it was an accurate but expensive proposition, as the 
 coefficients of expansion of the brass or zinc and iron or 
 steel had all to be determined individually for each pendu- 
 lum. Each rod had to be sized accurately, or if this was 
 not done, then each rod had to be fitted carefully to each 
 hole in the cross bars so as to move freely, without shake. 
 The rods were spread out for two purposes, to impress 
 the public and to secure uniform and speedy action in 
 changes of temperature. The weight, which increased 
 rapidly with the increase of diameter of the rod, made a 
 long and large seconds pendulum, some of them measuring 
 as much as sixty-two inches in length, and needing a large 
 bob to look in proportion. Various attempts w^ere made 
 to ornament the great expanse of the gridiron, harps, 
 wreaths and other forms in pierced metal being screwed 
 to the bars. The next advance was in substituting tubes for 
 
THE MODERN CLOCK. 4I 
 
 rods in the gridiron, securing an apparently large rod that 
 was at the same time stiff and light. Then came the era of 
 imitation, in which the rods were made of all brass, the 
 imitation steel portion being nickel plated. With the devel- 
 opment of plating they were still further cheapened by 
 being made of steel, with the supposedly brass rods plated 
 with brass and the steel ones with nickel. Thousands of 
 such pendulums are in use to-day ; they have the rods riv- 
 eted to the cross-pieces and are simply steel rods, subject to 
 change of length with every change in temperature. It 
 does no harm to ornament such pendulums, as the rods 
 themselves are merely ornaments, usually all of one metal, 
 plated to change the color. 
 
 As three rods were all that were necessary, the clock- 
 maker who desired a pendulum that was compensated soon 
 found his most easily made rod consisted of a zinc bar, 
 wide, thin and flat, placed between two steel parts, like the 
 meat and bread of a sandwich. This gives a flat and appar- 
 ently solid rod of metal which if polished gives a pleasing 
 appearance, and combines accurate performance with cheap- 
 ness of construction, so that any watchmaker may make it 
 himself, without expensive tools. 
 
 Flat Compensated Rod. — One of the most easily made 
 zinc and iron compensating pendulums, shown in detail in 
 Fig. 9, is as follows : A lead or iron bob, lens shaped, that 
 is, convex equally on each side, 9 inches diameter and an 
 inch and one-quarter thick at the center. A hole to be 
 made straight through its diameter ^ inch. One-half 
 through the diameter this hole is to be enlarged to ^4, inch 
 diameter. This will make the hole for half of its length 
 ]/2 inch and the remaining half ^ inch diameter. The 
 % hole must have a thin tube, just fitting it, and 5 inches 
 long. At one end of this tube is soldered in a nut, with a 
 hole tapped with a tap of thirty-six threads to the inch, and 
 }i inch diameter, and at the other end of the tube is 
 
42 
 
 THE MODERN CLOCK. 
 
 A, the lens-shaped bob; T P, the 
 total length of the compensating 
 part. 
 
 R, the upper round part of rod. 
 
 The side showing the heads of 
 the screws is the face side and is 
 finished. The screws 1,2,3,4 hold 
 the three pieces from separating, 
 but do not confine the front and 
 middle sections in their lengthwise 
 expansion along the rod, but are 
 screwed into the back iron section, 
 while the holes in the other two 
 sections are slotted smaller than 
 the screw heads. 
 
 The holes at the lower extreme 
 of combination 5, 6, 7, 8, 9 are for 
 adjustments in effecting a com- 
 pensation. 
 
 The pin at 10 is the steel adjusting 
 pin, and is only tight in the front 
 bar and zinc bars, being loose in 
 the back bar. 
 
 and P show the angles in the 
 back rod, T shows the angle in the 
 rod at the top, m shows the pin as 
 placed in the iron and zinc sections 
 wherfe they have been soldered as 
 described. 
 
 h shows the regulating nut car- 
 ried by the tube, as described, and 
 terminating in the nut D. 
 
 1 and i show the screw of 36 threads. 
 The nut D is to be divided on its 
 
 edge into 30 divisions. 
 
 n is the angle of the back bar to 
 which zinc is soldered. 
 
 Fig. 9. Pendulum with compensated rod of steel and zinc. 
 
THE MODERN CLOCK. 43 
 
 soldered a collar or disc one inch diameter, which is to be 
 divided into thirty divisions, for regulating purposes, as will 
 be described later on. The whole forms a nut into which 
 the rod screws, and the tube allows the nut to be pushed 
 up to the center of the diameter of the bob, through the 
 large hole, and the nut can be operated then by means of 
 the disc at its lower end. The rod, of flat iron, is in two sec- 
 tions, as follows : That section which enters the bob and 
 terminates in the regulating screw is flat for twenty-six 
 inches, and then rounded to Yz inch for six inches, and a 
 screw cut on its end for two inches, to fit the thread in the 
 nut. The upper end of this section is then to be bent 
 at a right angle, flatwise. This angle piece will be long 
 enough if only 3-16 inch long, so that it covers the thick- 
 ness of the zinc center rod. The zinc center rod is a bar of 
 the. metal, hammered or rolled, 25 inches long, 3-16 inch 
 thick, and ^ inch wide, and comes up against the angle 
 piece bent on the flat part of the lower section of the rod. 
 Now the upper section of the rod may be an exact duplicate 
 of the lower section, with the flat part only a little longer 
 than the zinc bar, say Yz inch, and the angle turned on the 
 end, as j)reviously described. The balance of the bar may 
 be forged into a rod of 5-16 inch diameter. As has been 
 stated, "the zinc bar is placed against the angle piece bent 
 on the upper end of the lower section of the rod, P, n. Fig. 
 9, and pins must be put through this angle piece into the 
 end of the zinc bar, to hold it in close contact with the iron 
 bar. The upper section of the rod is now to be laid on the 
 opposite side of the zinc bar, with its angle at the other end 
 of the zinc, but not in contact with it, say 1-16 inch left 
 between the angle and the zinc bar. Now all is ready to 
 clamp together — the two flat iron bars with the zinc between 
 them. After clamping, taking care to have the pinned end 
 of the zinc in contact with the angle and the free, or lower 
 end, removed from the other angle about 1-16 inch, three 
 screws should be put through all three bars, with their 
 
44 THE MODERN CLOCK. 
 
 heads all on the side selected for the front, and one screw 
 may be an inch from the top, another 3 inches from the 
 bottom, and one-half way between the two first mentioned. 
 Now the rod is complete in its composite form, and there 
 is left only the little detail to attend to. Two flat bars, with 
 their ends angled in one case and rounded in the other into 
 rods of given diameter, confining between them, as de- 
 scribed, a flat bar of wrought zinc of stated length and of 
 the same thickness and width as the iron bars, comprises 
 the active or compensating elements of the pendulum's rod. 
 The screws that are put through the three bars are each to 
 pass through the front iron bar, without threads in the bar, 
 and only the back iron bar is to have the holes tapped, 
 fitting the screws. All the corresponding holes in the zinc 
 are to be reamed a little larger than the diameter of the 
 screws, and to be freed lengthwise of the bar, to allow of 
 the bar's contracting and expanding without being con- 
 fined in this action by the screws. At the lower or free end 
 of the zinc bar are to be holes carried clear through all three 
 bars, while the combination is held firmly together by the 
 screws. These holes are to start at ^ inch from the end 
 of the zinc, and each carried straight through all three bars, 
 and then broached true and a steel pin made to accurately 
 fit them from the front side. These holes may be from 
 three to five in number, extending up to a safe distance from 
 the lower screw. The holes in the back bar, after boring, 
 are to be reamed larger than those in the front bar and zinc 
 bar. These holes and the pin serve for adjusting the com- 
 pensation. The pin holds the front bar and zinc from slip- 
 ping, or moving past one another at the point pinned, and 
 also allows the back bar to be free of the pin, and not under 
 the inflyence of the two front bars. The upper end of the 
 second iron section is, as has been mentioned, forged into 
 a round rod about 5-16 inch diameter, and this rod or 
 upper end is to receive the pendulum suspension spring, 
 which may be one single spring, or a compound spring, 
 as preferred. 
 
THE MODERN CLOCK. 45 
 
 Now that the pendulum is all ready to balance on the 
 knife edge, proceed as in case of the simple pendulum, 
 and ascertain at what point up the rod the spring must be 
 placed. In this pendulum the rod will be heavier in propor- 
 tion than the wood rod was to its bob, and the center of 
 gravity of the whole will be found higher up in the bob. 
 However, wherever in the bob the center of gravity is 
 found, that is the starting point to measure from to find the 
 total length of the rod, and the point for the spring. The 
 heavier the rod is in relation to the bob, the higher will the 
 center of gravity of the whole rise in the bob, and the 
 greater will be the total length of the entire pendulum. 
 
 In getting up a rod of the kind just described, the main 
 item is to get the parts all so arranged that there will be 
 very little settling of the joints in contact, particularly those 
 which sustain the weight of the bob and the whole dead 
 weight of the pendulum. The nut in the center of the 
 pendulum holds the weight of the bob only, but it should 
 fit against the shoulder formed for the purpose by the 
 juncture of the two holes, and the face of the nut should be 
 turned true and flat, so that there may not be any uneven 
 motion, and only the one imparted by the progressive one 
 of the threads. When this nut is put to its place for the 
 last time, and after all is finished, there should be a little 
 tallow put on to the face of the nut just where it comes 
 to a seat against the shoulder of the bob, as this shoulder 
 being not very well finished, the two surfaces coming in 
 contact, if left dry, might cut and tear each other, and help 
 to make the nut's action slightly unsteady and unreliable. 
 A finished washer can be driven into this lower hole up to 
 the center, friction tight, and serve as a reliable and finished 
 seat for the nut. 
 
 In reality, the zinc at the point of contact, where pinned to 
 the angle piece at the top of the lower section, is the point 
 of greatest importance in the whole combination, and if the 
 joint between the angle and the end of the zinc bar is 
 
46 THE MODERN CLOCK. 
 
 soldered with soft solder, the result will be that of greater 
 certainty in the maintenance of a steady rate. This joint 
 just mentioned can be soldered as follows: File the end 
 of the zinc and the inside surface of the angle until they fit 
 so that no appreciable space is left between them. Then, 
 with a soldering iron, tin the end of the zinc thoroughly 
 and evenly, and then put into the holes already made the 
 two steady pins. Now tin in the same manner the surface 
 of the angle, and see that the holes are free of solder, so that 
 the zinc bar will go to its place easily ; then between the 
 zinc and the iron, place a piece of thin writing paper, so 
 that the flat surfaces of the zinc and iron may not become 
 soldered. Set the iron bar upright on a piece of charcoal, 
 and secure it in this position from any danger of falling, 
 and then put the zinc to its place and see that the pins enter 
 and that the paper is between the surfaces, as described. 
 Put the screws into their places, and screw down on the 
 zinc just enough to hold it in contact with the iron bar, but 
 not so tight that the zinc will not readily move down and 
 rest firmly on the angle. Put a little soldering fluid on the 
 tinned joint, and blow with a blow pipe against the iron- 
 bar (not touching the zinc with the flame). When the 
 solder in the joint begins to flow, press the zinc down in 
 close contact with the angle, and then cool gradually, and if 
 all the points described have been attended to the joint will 
 be solidly soldered, and the two bars will be as one solid 
 bar bent against itself. The tinning leaves surplus solder on 
 the surfaces suflicient to make a solid joint, and to allow 
 some to flow into the pin holes and also solder the pin to 
 avoid any danger of getting loose in after time, and helps 
 make a much stronger joint. At the time the solder is 
 melted the zinc is sufliciently heated to become quite mal- 
 leable, and care must be taken not to force it down against 
 the angle in making the joint, or it may be distorted and 
 ruined at the joint. If carefully done the result will be 
 perfect. The paper between the surfaces burns, and is got 
 
THE MODERN CLOCK. 47 
 
 rid of in washing to remove the soldering fluid. Soda or 
 ammonia will help to remove all traces of the fluid. How- 
 ever, it is best, as a last operation, to put the joint in alcohol 
 for a minute. 
 
 This soldering makes the lower section and the zinc 
 practically one piece and without loose joint, and the next 
 joint is that made by the pin pinning the outside bar and the 
 zinc together. This is necessarily formed this way, as in 
 this stage of the operation we do not know just what length 
 the zinc bar will be to exactly compensate for the expansion 
 and contraction of the balance of the pendulum. By the 
 changing of the pin into the different holes, 5, 6, 7, 8, 9, 10, 
 Fig. 9, the zinc is made relatively longer or shorter, and so 
 a compensation is arrived at in time after the clock has been 
 running. After it is definitely settled where the pin will 
 remain to secure the compensation of the rod, then that 
 hole can have a screw put in to match the three upper ones. 
 This screw must be tapped into the front bar and the zinc, 
 and be very free in the back bar to allow of its expansion. 
 It is supposed that in this example given of a zinc and steel 
 compensation seconds pendulum that there has been due 
 allowance made in the lengths of the several bars to allow 
 for adjustment to temperature by the movements of the pin 
 along the course of the several holes described, but the zinc 
 is a very uncertain element, and its ultimate action is largely 
 influenced by its treatment after being cast. Differences of 
 working cast zinc under the hammer or rolls produce wide 
 differences practically, and therefore materially change the 
 results in its combination with, iron in their relative ex- 
 pansive action. Wrought zinc can be obtained of any of the 
 brass plate factories, of any dirriensions required, and will 
 be found to be satisfactory for the purpose in hand. 
 
 The adjusting pin should be well fitted to the holes in the 
 front iron bar, and also fit the corresponding ones in the 
 zinc bar closely, and if the holes are reamed smooth and 
 true with an English clock broach, then the pin will be 
 
48 THE MODERN CLOCK. 
 
 slightly tapering and fit the iron hole perfectly solid. After 
 one pair of these holes have been reamed, fit the pin and 
 drive it in place perfectly firm, and then with the broach 
 ream all the remaining holes to just the same diameter, 
 and then the pin will move along from one set of holes to 
 another with mechanically accurate results. Otherwise, if 
 poorly fitted, the full effect would not be obtained from the 
 compensating action in making changes in the pin from 
 one set of holes to another. This pin, if made of cast steel, 
 hardened and drawn to a blue, will on the whole be a very 
 good device mechanically. 
 
 Many means are used to effect the adjustments for com- 
 pensation, of more or less value, but whatever the means 
 used, it must be kept in mind that extra care must be taken 
 to have the mechanical execution first class, as on this very 
 much depends the steady rate of the pendulum in after 
 time. 
 
 Tubular Compensated Rods. — There are tubular pendu- 
 lums in the market which have a screw sleeve at the top of 
 the zinc element, and by this means the adjustments are 
 effected, and this is thought to be a very accurate mechan- 
 ism. The most common form of zinc and iron compensa- 
 tion is where the zinc is a tube combined with one iron tube 
 and a central rod, as shown in Figs. lo, ii, 12. The rod 
 is the center piece, the zinc tube next, followed by the iron 
 tube enveloping both. The relative lengths may be the 
 same as those just given in the foregoing example with the 
 compensating elements flat. The relative lengths of the 
 several members will be virtually the same in both com- 
 binations. 
 
 Tubular Compensation with Aluminum. — The pen- 
 dulum as seen by an observer appears to him as being a 
 simple single rod pendulum. Figs. 10 and 12 are front 
 and side views ; Fig. 1 1 is an enlarged view of its parts, the 
 
THE MODERN CLOCK, 
 
 49 
 
 upper being a sectional view. Its principal features are: 
 The steel rod S, Fig. ii, 4 mm. in diameter, having at its 
 upper end a hook for fastening to the suspension spring in 
 the usual way ; the lower end has a pivot carrying the bush- 
 ing, T, which solidly connects the steel rod, S, with the 
 aluminum tube. A, the latter being 10 mm. in diameter and 
 its sides 1.5 mm. in thickness of the wall. 
 
 The upper end of the aluminum tube is very close to the 
 pendulum hook and is also provided with a bushing, P, 
 Fig. II. This bushing is permanently connected at the 
 upper end of the aluminum tube with a steel tube, R, 16 mm. 
 in diameter and i mm. in thickness. The outer steel tube 
 is the only one that is visible and it supports the bob, the 
 lower part being furnished with a fine thread on which 
 the regulating nut, O, is movable, at the center of the bob. 
 
 For securing a central alignment of the steel rod, S, at its 
 lowest part, where it is pivoted, a bushing, M, Fig. 11, is 
 screwed into the steel tube, R. The lower end of the steel 
 tube, R, projects considerably below the lenticular bob 
 (compare Figs. 10 and 12) ; and is also provided with a 
 thread and regulating weight, G (Figs. 10 and 12), of 100 
 grammes in weight, which is only used in the fine regula- 
 tion of small variations from correct time. 
 
 The steel tube is open at the bottom and the index at its 
 lower end is fastened to a bridge. Furthermore all three 
 of the bushings, P, T and M, have each three radial cuts, 
 which will permit the surrounding air to act equally and at 
 the same time on the steel rod, S, the aluminum tube. A, and 
 the steel tube, R, and as the steel tube, R, is open at its 
 lower end, and as there is also a certain amount of space be- 
 tween the tubes, the steel rod, and the radial openings in 
 the bushings, there will be a draught of air passing through 
 them, which will allow the thin- walled tubes and thin steel 
 rod to promptly and equally adapt themselves to the temper- 
 ature of the air. 
 
Fig. 10. 
 
 Fig. U. 
 
 Fig. 12. 
 
THE MODERN CLOCK. 5I 
 
 The lenticular pendulum bob has a diameter of 24 cm., 
 and is made of red brass. The bob is supported at its cen- 
 ter by the regulating nut, O, Figs. 10 and 12. That the 
 bob may not turn on the cylindrical pendulum rod, the latter 
 is provided with a longitudinal groove and working therein 
 are the ends of two shoulder screws which are placed on 
 the back of the bob above and below the regulating nut, O ; 
 and thus properly controlling its movements. 
 
 From the foregoing description the action of the compen- 
 sation is readily explained. For the purpose of illustration 
 of its action we will accept the fact that there has been a 
 sudden rise in temperature. The steel rod, S, and the tube, 
 R, will lengthen in a downward direction (including the 
 suspension spring and the pendulum hook), conversely the 
 aluminum tube. A, which is fastened to the steel rod at one 
 end and the steel tube at the other, will lengthen in an 
 upward direction and thus equalize the expansion of the 
 tube, R, and rod, S. 
 
 As the coefficients of expansion of steel and aluminum are 
 approximately at the ratio of 1 12.0313 we find that with such 
 a pendulum construction — accurate calculations presumed 
 — we shall have a complete and exact coincidence in its 
 compensation ; in other words, the center of oscillation of 
 the pendulum will be under all conditions at the same dis- 
 tance from the bending point of the suspension spring. 
 
 This style of pendulum is made for astronomical clocks in 
 Europe and is furnished in two qualities. In the best qual- 
 ity, the tubes, steel rod, and the bob are all separately and 
 carefully tested as to their expansion, and their coefficients 
 of expansion fully determined in a laboratory ; the bush- 
 ings, P and M, are jeweled, all parts being accurately and 
 finely finished. In the second quality the pendulum is con- 
 structed on a general calculation and finished in a more 
 simple manner without impairing its ultimate efficiency. 
 
 At the upper part of the steel tube, R, there is a funnel- 
 shaped piece (omitted in the drawing) in which are placed 
 
52 THE MODERN CLOCK. 
 
 small lead and aluminum balls for the final regulation of the 
 pendulum without stopping it. 
 
 The regulation of this pendulum is effected in three 
 ways : 
 
 I. The preliminary or coarse regulation by turning the 
 regulating nut, O, and so raising or lowering the bob. 
 2. The finer regulation by turning the lOO grammes 
 weight, g, having the shape of a nut and turning on the 
 threaded part of the tube, R. 3. The precision regulation 
 is effected by placing small lead or aluminum balls in a 
 small funnel-shaped receptacle attached to the upper part 
 of the tube, R, or by removing them therefrom. 
 
 It will readily be seen that this form of pendulum can be 
 used with zinc or brass instead of aluminum, by altering the 
 lengths of the inner rod and the compensating tube to suit 
 the expansion of the metal it is decided to use ; also that 
 alterations in length may be made by screwing the bushings 
 in or out, provided that the tube be long enough in the 
 first place. After securing the right position the bushings 
 should have pins driven into them through the tube, in order 
 'to prevent further shifting. 
 
CHAPTER IV. 
 
 THE CONSTRUCTION OF MERCURIAL PENDULUMS. 
 
 Owing to the difficulty of calculating the expansive ratios 
 of metal which (particularly with brass and zinc) vary 
 slightly with differences of manufacture, the manufacture 
 of compensated pendulums from metal rods cannot be re- 
 duced to cutting up so many pieces and assembling them 
 from calculations made previously, so that each must be 
 separately built and tested. While this is not a great draw- 
 back to the jeweler who wants to make himself a pendu- 
 lum, it becomes a serious difficulty to a manufacturer, and 
 hence a cheaper combination had to be devised to prevent 
 the cost of compensated pendulums from seriously inter- 
 fering with their use. The result was the pendulum com- 
 posed of a steel rod and a quantity of mercury, the latter 
 forming the principal weight for the bob and being con- 
 tained in steel or glass jars, or jars of cast iron for the 
 heavier pendulums. Other metals will not serve the pur- 
 pose, as they are corroded by the mercury, become rotten 
 and lose their contents. 
 
 Mercury has one deficiency which, however, is not seri- 
 ous, except for the severe conditions of astronomical obser- 
 vatories. It will oxidize after long exposure to the air, 
 when it must be strained and a fresh quantity of metal 
 added and the compensation freshly adjusted. To an as- 
 tronomer this is a serious objection, as it may interfere with 
 his work for a month, but to the jeweler this is of little 
 moment as the rates he demands will not be seriously affect- 
 ed for about ten years, if the jars are tightly covered. 
 
 To construct a reliable gridiron pendulum would cost 
 about fifty dollars while a mercurial pendulum can be well 
 made and compensated for about twenty-five dollars, hence 
 the popularity of the latter form. 
 
 53 
 
54; ' THE MODERN CLOCK, 
 
 Zinc will lengthen under severe variations of tempera- 
 ture as the following will show: Zinc has a decided objec- 
 tionable quality in its crystalline structure that with temper- 
 ature changes there is very unequal expansion and con- 
 traction, and furthermore, that these changes occur sud- 
 deiily; this often results in the bending of the zinc rod,, 
 causing a binding to take place, which naturally enough 
 prevents the correct working of the compensation. 
 
 It is probably not very well known that zinc can change 
 its length at one and the same temperature, and that this 
 peculiar quality must not be overlooked. The U. S. Lake 
 Survey, which has under its charge the triangulation of the 
 great lakes of the United States, has in its possession a steel 
 meter measure, R, 1876; a metallic thermometer composed 
 of a steel and zinc rod, each being one meter in length,, 
 marked M. T., 1876s, and M. T. 1876Z; and four metallic 
 thermometers, used in connection with the base apparatus, 
 which likewise are made of steel and zinc rods, each of 
 these being four meters in length. All of these rods were 
 made by Repsold, of Hamburg. Comparisons between these 
 different rods show peculiar variations, and which point to 
 the fact that their lengths at the same degree of temperature 
 are not constant. For the purpose of determining these 
 variations accurate investigations were undertaken. The 
 metallic thermometer M. T. 1876 was removed from an ob- 
 servatory room having an equal temperature of about 2° C. 
 and placed for one day in a temperature of 4-24° C, and 
 also for the same period of time in one of — 20° C ; it was 
 then replaced in the observatory room, where it remained 
 for twenty-four hours, and comparisons were made during 
 the following three days with the steel thermometer R, 
 1876, which had been left in the room. From these obser- 
 vations and comparisons the following results were tabu- 
 lated, which give the mean leng^ths of the zinc rods of the 
 metallic thermometer. The slight variations of temperature 
 in the observatory room were also taken into consideration 
 in the calculations : 
 
MODERN CLOCK. ^^^' ^^^SgS 
 
 M. T. 1876s. M. T. 1876Z. 
 mm. mm. 
 
 Februar}^ 16-24 — 0.0006 + 0.0152, previous 7 days at + 24°C 
 
 February 25-27 — 0.0017 — o.ooii, previous i day at — 20°C 
 
 March 2-4 + 0.0005 + 0.0154, previous i day at + 24° C. 
 
 March 5-8 — 0.0058 — 0.0022, previous i day at — 20° C. 
 
 These investigations clearly indicate, without doubt, that 
 the zinc rod at one and the same temperature of about 2° C, 
 is 0.018 mm. longer after having been previously heated to 
 24° C. than when cooled before to — 20° C. 
 
 A similar but less complete examination was made with 
 the metallic thermometer four meters in length. These 
 trials were made by that efficient officer, General Corn- 
 stock, gave the same results, and completely prove that in 
 zinc there are considerable thermal after-effects at work. 
 
 To prove that zinc is not an efficient metal for compensa- 
 tion pendulums when employed for the exact measurement 
 of time, a short calculation may be made — using the above 
 conclusions — that a zinc rod one meter in length, after 
 being subjected to a difference of temperature of 44 C. will 
 alter its length 0.018 mm. after having been brought back 
 to its initial degree. For a seconds pendulum with zinc 
 compensation each of the zinc rods would require a length 
 of 64.9 cm. With the above computations we get a differ- 
 ence in length of 0.0117 mm. at the same degree of temper- 
 ature. Since a lengthening of the zinc rods without a suit- 
 able and contemporaneous expansion of the steel rods is 
 synonymous with a shortening of the effectual pendulum 
 length, we have, notwithstanding the compensation, a short- 
 ening of the pendulum length of 0.017 mm., which corre- 
 sponds to a change in the daily rate of about 0.5 seconds. 
 
 This will sufficiently prove that zinc is unquestionably 
 not suitable for extremely accurate compensation pendu- 
 lums, and as neither is permanent under extremes of tem- 
 perature the advantages of first cost and of correction of 
 error appear to lie with the mercurial form. 
 
56 THE MODERN CLOCK. 
 
 The average mercurial compensation pendulums, on sale 
 in the trade are often only partially compensated, as the 
 mercury is nearly always deficient in quantity relatively, 
 and not high enough in the jar to neutralize the action of 
 the rigid metallic elements, composing the structure. The 
 trouble generally is that the mercury forms too small a pro- 
 portion of the total weight of the pendulum bob. There 
 is a fundamental principle governing these compensating 
 pendulums that has to be kept in mind, and that is that one 
 of the compensating elements is expected to just undo what 
 the other does and so establish through the medium of 
 physical things the condition of the ideal pendulum, with- 
 out weight or elements outside of the bob. As iron and 
 mercury, for instance, have a pretty fixed relative expansive 
 ratio, then whatever these ratios are after being found, must 
 be maintained in the construction of the pendulum, or the 
 results cannot be satisfactory. 
 
 First, there are 39.2 inches of rod of steel to hold the 
 bob between the point of suspension and the center of oscil- 
 lation, and it has been found that, constructively, in all 
 the ordinary forms of these pendulums, the height of mer- 
 cury in the bob cannot usually be less than 7.5 inches. Sec- 
 ond, that in all seconds pendulums the length of the metal 
 is fixed substantially, while the height of the mercury is a 
 varying one, due to the differing weights of the jars, 
 straps, etc. 
 
 Third, the mercury, at its minimum, cannot with jars of 
 ordinary weight be less in height in the jar than 7.5 inches, 
 to effectually counteract what the 39.2 inches of iron does 
 in the way of expanding and contracting under the same 
 exposure. 
 
 Whoever observes the great mass of pendulums of this 
 description on sale and in use will find that the height 
 of the mercury in the jar is not up to the amount given 
 above for the least quantity that will serve under the most 
 favorable circumstances of construction. The less weight 
 
THE MODERN CLOCK. 57 
 
 there is in the rod, jar and frame, the less is the height 
 of mercury which is required ; but with most of the pendu- 
 lums made in the present day for the market, the height 
 given cannot be cut short without impairing the quality and 
 efficiency of the compensation. Any amount less will have 
 the effect of leaving the rigid metal in the ascendancy ; or, 
 in other words, the pendulum will be under compensated 
 and leave the pendulum to feel heat and cold by raising and 
 lowering the . center of oscillation of the pendulum and 
 hence only partly compensating. A jar with only six inches 
 in height of mercury will in round numbers only correct the 
 temperature error about six-sevenths. 
 
 Calculations of Weights. — As to how to calculate the 
 amount of mercury required to compensate a seconds pendu- 
 lum, the following explanation should make the matter 
 clear to anyone having a fair knowledge of arithmetic only, 
 though there are several points to be considered which 
 render it a rather more complicated process than would ap- 
 pear at first sight. 
 
 1st. The expansion in length of steel and cast iron, as 
 given in the tables (these tables differ somewhat in the 
 various books), is respectively .0064 and .0066, while mer- 
 cury expands .1 in bulk for the same increase of tempera- 
 ture. If the mercury were contained in a jar which itself 
 had no expansion in diameter, then all its expansion would 
 take place in height, and in round numbers it would expand 
 sixteen times more than steel, and we should only require 
 (neglecting at present the allowance to be explained under 
 head 3) to make the height of the mercury — reckoned from 
 the bottom of the jar (inside) to the middle of the column 
 of mercury contained therein — one-sixteenth of the total 
 length of the pendulum measured from the point of sus- 
 pension to the bottom of the jar, assuming that the rod and 
 the jar are both of steel, and that the center of oscillation 
 is coincident with the center of the column of mercury. 
 
JS THE MODERN CLOCK. 
 
 Practically in these pendulums, the center of oscillation 
 is almost identical with the center of the bob. 
 
 2d. As we cannot obtain a jar having no expansion in 
 diameter, we must allow for such expansion as follows,, 
 and as cast-iron or steel jars of cylindrical shape are un- 
 doubtedly the best, we will consider that material and form 
 only. 
 
 As above stated, cast iron expands .0066, so that if the 
 original diameter of the jar be represented by i, its ex- 
 panded diameter will be 1.0066. Now the area of any circle 
 varies as the square of its diameter, so that before and after 
 its expansion the areas of the jar will be in the ratio of i^ 
 to 1.0066^; that is, in the proportion of i to i. 01 3243; or 
 in round numbers it will be one-seventy-sixth larger in area 
 after expansion than before. It is evident that the mercury 
 will then expand sideways, and that its vertical rise will be 
 diminished to the same extent. Deduct, therefore, the one- 
 seventy-sixth from its expansion in bulk (one-tenth) and we 
 get one-eleventh (or more exactly .086757) remaining. 
 This, then, is the actual vertical rise in the jar, and when 
 compared with the expansion of steel in length it will be 
 found to be about thirteen and a half tim.es greater (more 
 exactly 13-556). 
 
 The mercury, therefore (still neglecting head No. 3)^ 
 must be thirteen and a half times shorter than the length 
 of the pendulum, both being measured as explained above. 
 The pendulum will probably be 43.5 inches long to the 
 bottom of the jar; but as about nine inches of it is cast 
 iron, which has a slightly greater rate of expansion than 
 steel, we will call the length 44 inches, as the half inch 
 added will make it about equivalent to a pendulum entirely 
 of steel. If the height of the mercury be obtained by di- 
 viding 44 by 13.5, it will be 3.25 inches high to its center, 
 or 6.5 inches high altogether; and were it not for the fol- 
 lowing circumstance, the pendulum would be perfectly 
 compensated. 
 
THE MODERN CLOCK. 59 
 
 3d. The mercury is the only part of the bob which ex- 
 pands upwards; the jar does not rise, its lower end being 
 carried downward by the expansion of the rod, which sup- 
 ports it. In a well-designed pendulum, the jar, straps, etc.;, 
 will be from one-fourth to one-third the weight of the mer- 
 cury. Assume them to be seven pounds and twenty-eight 
 pounds respectively; therefore, the total weight of the bob 
 is thirty-five pounds; but as it is only the mercury (four- 
 fifths) of this total that rises with an increase of tempera- 
 ture, we must increase the weight of the mercury in the 
 proportion of five to four, thus 6.5 X 5 -r- 4 = ^H inches. 
 Or, what is the same thing, we add one-fourth to the 
 amount of mercury, because the weight of the jar is one- 
 fourth of that of the mercury. Eight and one-eighth 
 inches is, therefore, the ultimate height of the mercury re- 
 quired to compensate the pendulum with that weight of jar. 
 If the jar had been heavier, say one-third the weight of the 
 mercury, then the latter would have to be nearly 8.75 inches 
 high. 
 
 If the jar be required to be of glass, then we substitute 
 the expansion of that material in No. 2 and its weight in 
 No. 3. 
 
 In the above method of calculating, there are two slight 
 elements of uncertainty: ist. In assuming that the center 
 of oscillation is coincident with the center of the bob ; how^- 
 ever, I should suppose that they would never be more than 
 .25 inch apart, and generally much nearer. 2d. The weight 
 of the jar cannot well be exactly known until after it is 
 finished (i. e., bored smooth and parallel inside, and turned 
 outside true with the interior), so that the exact height of 
 the mercury cannot be easily ascertained till then. 
 
 I may explain that the reason (in Nos. i and 2) we meas- 
 ure the mercury from the bottom to the center of the col- 
 umn, is that it is its center which we wish to raise when an 
 increase of temperature occurs, so that the center may 
 always be exactly the same distance from the point of 
 
6o THE MODERN CLOCK. 
 
 suspension ; and we have seen that 3.25 inches is the neces- 
 sary quantity to raise it sufficiently. Now that center could 
 not be the center without it had as much mercury over it as 
 it has under it; hence we double the 3.25 and get the 6.5 
 inches stated. 
 
 ' From the foregoing it will be seen that the average mer- 
 cury pendulums are better than a plain rod, from the fact 
 that the mercury is free to obey the law of expansion, and 
 so, to a certain degree, does counteract the action of the 
 balance of the metal of the pendulum, and this with a 
 degree of certainty that is not found in the gridiron form, 
 provided always that the height and amount of the mer- 
 cury are correctly proportional to the total weight of the 
 pendulum. 
 
 Compensating Mercurial Pendulums. — To compen- 
 sate a pendulum of this kind takes time and study. The 
 first thing to do is to place maximum and minimum ther- 
 mometers in the clock case, so that you can tell the tem- 
 perature. 
 
 Then get the rate of the clock at a given temperature. 
 For example, say the clock gains two seconds in twenty- 
 four hours, the temperature being at 70°. Then see how 
 much it gains when the temperature is at 80°. We will 
 say it gains two seconds more at 80° than it does when 
 the temperature is at 70°. 
 
 In that case we must remove some of the mercury in 
 order to compensate the pendulum. To do this take a 
 syringe and soak the cotton or whatever makes the suction 
 in the syringe with vaseline. The reason for doing this is 
 that mercury is very heavy and the syringe must be air 
 tight before you can take any of the mercury up into it. 
 
 You want to remove about two pennyweights of mer- 
 cury to every second the clock gains in twenty-four hours. 
 Now, after removing the mercury the clock will lose time, 
 because the pendulum is lighter. You must then raise the 
 
THE MODERN CLOCK. 6l 
 
 ball to bring it to time. You then repeat the same opera- 
 tion by getting the rate at 76° and 80° again and see if it 
 gains. When the temperature rises, if the pendulum still 
 gains, you must remove more mercury; but if it should 
 lose time when the temperature rises you have taken out 
 too much mercury and you must replace some. Continue 
 this operation until the pendulum has the same rate, wheth- 
 er the temperature is high or low, raising the bob when 
 you take out mercury to bring it to time, and lowering the 
 bob when you put mercury in to bring it to time. 
 
 To compensate a pendulum takes time and study of the 
 clock, but if you follow out these instructions you will suc- 
 ceed in getting the clock to run regularly in both summer 
 and winter. 
 
 Besides the oxidation, which is an admitted fault, there 
 are two theoretical questions which have to do with con- 
 struction in deciding between the metallic and mercurial 
 forms of compensation. We will present the claims of each 
 side, therefore, with the preliminary statement that (for all 
 except the severest conditions of accuracy) either form, if 
 well made will answer every purpose and that therefore, 
 except in special circumstances, these objections are more 
 theoretical than real. 
 
 The advocates of metallic compensation claim that where 
 there are great differences of temperature, the compensated 
 rod, with its long bars will answer more quickly to temper- 
 ature changes as follows : 
 
 The mercurial pendulum, when in an unheated room 
 and not subjected to sudden temperature changes, gives 
 very excellent results, but should the opposite case occur 
 there will then be observed an irregularity in the rate of 
 the clock. The causes which produce these effects are 
 various. As a principal reason for such a condition it may 
 be stated that the compensating mercury occupies only 
 about one-fifth the pendulum length, and it inevitably fol- 
 lows that when the upper strata of the air is warmer than 
 
^2 THE MODERN CLOCK. 
 
 the lower, in which the mercury is placed, the steel pendu- 
 lum rod will expand at a different ratio than the mercury, 
 as the latter is influenced by a different degree of tempera- 
 ture than the upper part of the pendulum rod. The natural 
 effect will be a lengthening of the pendulum rod, notwith- 
 standing the compensation, and therefore, a loss of time by 
 the clock. 
 
 Two thermometers, agreeing perfectly, were placed in 
 the case of a clock, one near the point of suspension, and the 
 other near the middle of the ball, and repeated experiments, 
 showed a difference between these two thermometers of 7° 
 to io^°F.,the lower one indicating less than the higher one. 
 The thermometers were then hung in the room, one at 
 twenty-two inches above the floor, and the other three feet 
 higher, when they showed a difference of 7° between them. 
 The difference of 2.5° more which was found inside the 
 case proceeds from the heat striking the upper part of the 
 case ; and the wood, though a bad conductor, gradually in- 
 creases in temperature, while, on the contrary, the cold 
 rises from the floor and acts on the lower part of the case, 
 The same thermometers at the same height and distance in 
 an unused room, which was never warmed, showed no dif- 
 ference between them ; and it would be the same, doubtless, 
 in an observatory. 
 
 From the preceding it is very evident that the decrease of 
 rate of the clock since December 13 proceeded from the rod 
 of the pendulum experiencing 7° to 10.5° F. greater heat 
 than the mercury in the bob, thus showing the impossibility 
 of making a mercurial pendulum perfectly compensating 
 in an artificially heated room which varies greatly in tem- 
 perature. I should remark here that during the entire 
 winter the temperature in the case is never more than 68° 
 F., and during the summer, when the rate of the clock was 
 regular, the thermometer in the case has often indicated 
 72° to yy"" F. 
 
 The gridiron pendulum in this case would seem prefer- 
 able, for if the temperature is higher at the top than at the 
 
THE MODERN CLOCK. 63 
 
 lower part, the nine compensating rods are equally effected 
 by it. But in its compensating action it is not nearly as 
 regular, and it is very difficult to regulate it, for in any 
 room (artificially heated) it is impossible to obtain a uni- 
 form temperature throughout its entire length, and with- 
 out that all proofs are necessarily inexact. 
 
 These facts can also be applied to pendulums situated in 
 heated rooms. In the case of a rapid change in tempera- 
 ture taking place in the observatory rooms, under the domes 
 of observatories, especially during the winter months, and 
 which are of frequent occurrence, a mercurial compensa- 
 tion pendulum, as generally made, is not apt to give a re- 
 liable rate. Let us accept the fact, as an example, of a 
 considerable fall in the temperature of the surrounding air ; 
 the thin, pendulum rod will quickly accept the same tempera- 
 ture, but with the great mass of mercury to be acted upon 
 the responsive effects will only occur after a considerable 
 lapse of time. The result will be a shortening of the pendu- 
 lum length and a gain in the rate until the mercury has 
 had time to respond, notwithstanding the compensation. 
 
 Others who have expressed their views in writing seem 
 to favor the idea that this inequality in the temperature of 
 the atmosphere is unfavorable to the accurate action of the 
 mercurial form of compensation; and however plausible 
 and reasonable this idea ma}^ seem at first notice, it will not 
 take a great amount of investigation to show that, instead 
 of being a disadvantage, its existence is beneficial, and an 
 important element in the success of mercurial pendulums. 
 
 It appears that the majority of those who have proposed, 
 or have tried to improve Graham's pendulum have over- 
 looked the fact that different substances require different 
 quantities of heat to raise them to the same temperature. In 
 order to warm a certain weight of water, for instance, 
 to the same degree of heat as an equal weight of oil, or an 
 equal weight of mercury, twice as much heat must be given 
 to the water as to the oil, and thirty times as much as to the 
 
64 THE MODERN CLOCK. 
 
 mercury ; while in cooling down again to a given tempera- 
 ture, the oil will cool twice as quick as the water, and the 
 mercury thirty times quicker than the water. This phenom- 
 enon is accounted for by the difference in the amount of 
 latent heat that exists in various substances. On the au- 
 thority of Sir Humphrey Davy, zinc is heated and cooled 
 again ten and three-quarters times quicker than water, brass 
 ten and a half times quicker, steel nine times, glass eight 
 and a half times, and mercury is heated and cooled again 
 thirty times quicker than water. 
 
 From the above it will be noticed that the difference in 
 the time steel and mercury takes to rise and fall to a given 
 temperature is as nine to thirty, and also that the difference 
 in the quantity of heat that it takes to raise steel and mer- 
 cury to a given temperature is in the ratio of nine to thirty. 
 
 Now, without entering into minute details on the prop- 
 erties which different substances possess for absorbing or 
 reflecting heat, it is plain that mercury should move in a 
 proportionally different atmosphere from steel in order to 
 be expanded or contracted a given distance in the same 
 length of time ; and to obtain this result the amount of dif- 
 ference in the temperature of the atmosphere at the opposite 
 ends of the pendulum must vary a little more or less accord- 
 ing to the nature of the material the mercury jars are con- 
 structed from. 
 
 Differences in the temperature of the atmosphere of a 
 room will generally vary according to its size, the height 
 of the ceiling, and the ventilation of the apartment; and if 
 the difference must continue to exist, it is of importance 
 that the difference should be uniformly regular. We must 
 not lose sight of the fact, however, that clocks having these 
 pendulums, and placed in apartments every way favorable 
 to an equal temperature, and in some instances, the clocks 
 and their pendulums incased in double casing in order to 
 more effectually obtain this result, still the rates of the 
 clock show the same eccentricities as those placed in less 
 
THE MODERN CLOCK. 65 
 
 favorable position. This clearly shov/s that many changes 
 in the rates of fine clocks are due to other causes than a 
 change in the temperature of the surounding atmosphere. 
 Still it must be admitted that any change in the condition of 
 the atmosphere that surrounds a pendulum is a most formid- 
 able obstacle to be overcome by those who seek to improve 
 compensated pendulums, and it would be of service to them 
 to know all that can possibly be known on the subject. 
 
 The differences spoken of above have resulted in some 
 practical improvements, which are: ist, the division of the 
 mercury into two, three or four jars in order to expose as 
 much surface as possible to the action of the air, so that 
 the expansion of the mercury should not lag behind that of 
 the rod, which it will do if too large amounts of it are kept 
 in one jar. 2nd, the use of very thin steel jars made from 
 tubing, so that the transmission of heat from the air to the 
 mercury may be hastened as much as possible. 3rd, the in- 
 crease in the number of jars makes a thinner bob than a 
 single jar of the same total weight and hence gives an ad- 
 vantage in decreasing the resistant effect of air friction in 
 dense air, thereby decreasing somewhat the barometric 
 error of the pendulum. 
 
 The original form of mercurial pendulums, as made by 
 Graham, and still used in tower and other clocks where 
 extraordinary accuracy is not required, was a single jar 
 which formed the bob and had the pendulum rod extending 
 into the mercury to assist in conducting heat to the variable 
 element of the pendulum. It is shown in section in Fig, 
 ii3, which is taken from a working drawing for a tower 
 clock. 
 
 The pendulum. Fig. 13, is suspended from the head or 
 cock shown in the figure, and supported by the clock frame 
 itself, instead of being hung on a wall, since the intention 
 is to set the clock in the center of the clockroom, and 
 also because the weight, forty pounds, is not too much for 
 the clock frame to carry. The head. A, forms a revolving 
 
66 THE MODERN CLOCK. ' 
 
 thumb-nut, which is divided into sixty parts around the 
 circumference of its lower edge, and the regulating screw, 
 B, is threaded ten to the inch. A very fine a'djustment is 
 thus obtained for regulating the time of the pendulum. The 
 lower end of the regulating screw, B, holds the end of the 
 pendulum spring, E, which is riveted between two pieces 
 of steel, C, and a pin, C, is put through them and the end 
 of the regulating screw, by which to suspend the pendulum. 
 
 The cheeks or chops are the pieces D, the lower edges 
 of which form the theoretical point of suspension of the 
 pendulum. These pieces must be perfectly square at their 
 lower edges, otherwise the center of gravity would describe 
 1 cylindrical curve. The chops are clamped tightly in place 
 by the setscrews, D', after the pendulum has been hung. 
 
 The lower end of the regulating screw is squared to fit the 
 ways and slotted on one side, sliding on a pin to prevent its 
 turning and therefore twisting the suspension spring when 
 it is raised or lowered. 
 
 The spring is three inches long between its points of 
 suspension, one and three-eighths inches wide, and one- 
 sixtieth of an inch thick. Its lower end is riveted between 
 two small blocks of steel, F, and suspended from a pin, F', 
 in the upper end of the cap, G, of the pendulum rod. 
 
 The tubular steel portion of the pendulum rod is seven- 
 eighths of an inch in diameter and one-thirty-second of an 
 inch thickness of the wall. It is enclosed at each end by the 
 solid ends, G and L, and is made as nearly air tight as 
 possible. 
 
 The compensation is by mercury inclosed in a cast-iron 
 bob. The mercury, the bob and the- rod together weigh 
 forty pounds. The bob of the pendulum is a cast-iron jar, 
 K, three inches in diameter inside, one-quarter inch thick 
 at the sides, and five-sixteenths thick at the bottom, with 
 the cap, J, screwed into its upper end. The cap, J, forms 
 also the socket for the lower end of the pendulum rod, H. 
 The rod, L, one-quarter inch in diameter, screws into the 
 cap, J, and its large end at the same time forms a plug 
 
THE MODERN CLOCK. 
 
 67 
 
 ■±; 
 
 Fig. 13. 
 
68 THE MODERN CLOCK. 
 
 for the lower end of the pendulum tube, H. The pin, J', 
 holds all these parts together. The rod, L, extends nearly to 
 the bottom of the jar, and forms a medium for the trans- 
 mission of the changes in temperature from the pendulum 
 tube to the mercury. The screw in the cap, J, is for filling 
 or emptying the jar. The jar is finished as smoothly as 
 possible, outside and inside, and should be coated with at 
 least three coats of shellac inside. Of course if one was 
 building an astronomical clock, it would be necessary to 
 boil the mercury in the jar in order to drive off the layer of 
 air between the mercury and the walls of the jar, but with 
 the smooth finish the shellac will give, in addition to the 
 good work of the machinist, the amount of air held by 
 the jar can be ignored. 
 
 The cast-iron jar was decided upon because it was safer 
 to handle, can be attached more firmly to the rod with less 
 multiplication of parts, and also on account of the weight 
 as compared with glass, which is the only other thing that 
 should be used, the glass requiring a greater height of jar 
 for equal weight. In making cast iron jars, they should al- 
 ways be carefully turned inside and out in order that the 
 walls of the jar may be of equal thickness throughout; then 
 they will not throw the pendulum out of balance when they 
 are screwed up or down on the pendulum rod in making 
 the coarse regulation before timing by the upper screw. 
 The thread on the rod should have the cover of the jar at 
 about the center of the thread when nearly to time and 
 that portion which extends into the jar should be short 
 enough to permit this. 
 
 Ignoring the rod and its parts for the present, and calling 
 the jar one-third of the weight of the mercury, we shall 
 find that thirty pounds of mercury, at .49 pounds per cubic 
 inch, will fill a cylinder which is three inches inside diam- 
 eter to a height of 8.816 inches, after deducting for the 
 mass of the rod L, when the temperature of the mercury is 
 60 degrees F. Mercury expands one-tenth in bulk, while 
 
THE MODERN CLOCK. 69 
 
 cast-iron expands .0066 in diameter: so the sectional area 
 increases as 1,0066^ or 1.0132 to i, therefore the mercury 
 will rise .1 — .013243, or .086757; then the mercury in our 
 jar will rise .767 of an inch in the ordinary changes of 
 temperature, making a total height of 9.58 inches to provide 
 for; so the jar was made ten inches long. 
 
 Pendulums of this pattern as used in the high grade 
 English clocks, are substantially as follows: Rod of steel 
 5-16 inch diameter; jar about 2.1 inches diameter inside 
 and 8}i inches deep inside. The jar may be wrought or 
 cast iron and about ^ of an inch thick with the cover to 
 screw on with fine thread, making a tight joint. The cover 
 of the jar is to act as a nut to turn on the rod for regula- 
 tion. The thread cut on the rod should be thirty-six to 
 the inch, and fit into the jar cover easily, so that it may 
 turn without binding. With a thirty-six thread one turn 
 of the jar on the rod changes the rate thirty seconds per 
 day and by laying ofT on the edge of the cover 30 divisions, 
 a scale is made by which movements for one second per 
 day are obtained. 
 
 We will now describe (Fig. 14) the method of making a 
 mercurial pendulum to replace an imitation gridiron pendu- 
 lum for a Swiss, pin escapement regulator, such as is 
 commonly found in the jewelry stores of the United States, 
 that is, a clock in which the pendulum is supported by the 
 plates of the movement and swings between the front plate 
 and the dial of the movement. In thus changing our pendu- 
 lum, we shall desire to retain the upper portion of the old 
 rod, as the fittings are already in place and we shall save 
 considerable time and labor by this course. As the pendu- 
 lum is suspended from the movement, it must be lig;hter in 
 weight than if it were independently supported by a cast 
 iron bracket, as shown in Fig. 6, so we will make the 
 weig^ht about that of the one we have removed, or about 
 twelve pounds. If it is desired to make the pendulum 
 heavier, four jars of the dimensions given would make it 
 
yO THE MODERN CLOCK. 
 
 weigh about twenty pounds, or four jars of one inch diame- 
 ter would make a thinner bob and one weighing about 
 fourteen pounds. As the substitution of a different number 
 or different sizes of jars merely involves changing the 
 lengths of the upper and lower bars of the frame, further 
 drawings will be unnecessary, the jeweler having sufficient 
 mechanical capacity to be able to make them for himself. 
 
 1 might add, however, that the late Edward Howard, in 
 building his astronomical clocks, used four jars containing 
 twenty-eight pounds of mercury for such movements, and 
 the perfection of his trains was such that a seven-ounce 
 driving weight was sufficient to propel the thirty pound 
 pendulum. 
 
 The two jars are filled with mercury to a height of jYz 
 inches, are i% inches in diameter outside and 8% inches in 
 height outside. The caps and foot pieces are screwed on 
 and when the foot pieces are screwed on for the last time 
 the screw threads should be covered with a thick shellac 
 varnish which, when dry, makes the joint perfectly air 
 tight. The jars are best made of the fine, thin tubing, used 
 in bicycles, which can be purchased from any factory, of 
 various sizes and thickness. In the pendulum shown in the 
 illustration, the jar stock is close to 14 wire gauge, or about 
 
 2 mm. in thickness. In cutting the threads at the ends of the 
 jars they should be about 36 threads to the inch, the same 
 number as the threads on the lower end of the rod used to 
 carry the regulating nut. A fine thread makes the best job 
 and the tightest joints. The caps to the jars are turned 
 up from cold rolled shafting, it being generally good stock 
 and finishes well. The threads need not be over 3-16 inch, 
 which is ample. Cut the square shoulder so the caps and 
 foot pieces come full up and do not show any thread when 
 screwed home. These jars will hold ten pounds of mercury 
 and this weight is about right for this particular style of 
 pendulum. The jars complete will weigh about seven ounces 
 each. 
 
THE MODERN CLOCK. 
 
 71 
 
 1 
 
 l.lVtfMut 3 
 
 s n 
 
 n 
 
 >=i 
 
 
 / , , \ 
 
 \_ ' I 
 
 Fig. 14. 
 
72 THE MODERN CLOCK. 
 
 The frame is also made of steel and square finished 
 stock is used as far as possible and of the quality used in the 
 caps. The lower bar of the frame is six inches long and 
 5/s inch square at the center and tapered, as shown in the 
 illustration. It is made 'light by being planed away on the 
 under side, an end view being shown at 3. The top 
 bar of the frame, shown at 4, is planed away also and 
 is one-half inch square the whole length and is six inches 
 long. The two side rods are to bind the two bars together, 
 and with the four thumb nuts at the top and bottom make a 
 strong light frame. 
 
 The pendulum described is nickel plated and polished, ex,- 
 cept the jars, which are left half dead; that is, they are 
 frosted with a sand blast and scratch brushed a little. The 
 effect is good and makes a good contrast to the polished 
 parts. The side rods are five inches apart, which leaves 
 one-half inch at the ends outside. 
 
 The rod is 5-16 of an inch in diameter and 33 inches long 
 from the bottom of the frame at a point where the regulat- 
 ing nut rests against it to the lower end of the piece of the 
 usual gridiron pendulum shown in Fig. 14 at 10. This piece 
 shown is the usual style and size of those in the majority 
 of these clocks and is the standard adopted by the makers. 
 This piece is 11% inches long from the upper leaf of the 
 suspension spring, which is shown at 12, to the lower end 
 marked 10. By cutting out the lower end of this piece, as 
 showr at 10, and squaring the upper end of the rod, pin- 
 ning it into the piece as shown, the union can be made easily 
 and any little adjustments for length can be made by drilling 
 another set of holes in the rod and raising the pendulum by 
 so doing to the correct point. A rod whose total length 
 is 37 inches will leave 2 inches for the prolongation below 
 the frame carrying the regulating nut, 9, and for the portion 
 
THE MODERN CLOCK. 73 
 
 squared at the top, and will then be so long that the rate 
 of the clock will be slow and leave a surplus to be cut off 
 either at the top or bottom, as may seem best. 
 
 The screw at the lower end carrying the nut should have 
 36 threads to the inch and the nut graduated to 30 divisions, 
 each of which is equal in turning the nut to one minute in 
 24 hours, fast or slow, as the case may be. 
 
 The rod should pass through the frame bars snugly and 
 not rattle or bind. It also should have a slot cut so that a pin 
 can be put through the upper bar of the frame to keep the 
 frame from turning on the rod and yet allow it to move up 
 and down about an inch. The thread at the lower end of the 
 rod should be cut about two inches in length and when cut- 
 ting off the rod for a final length, put the nut in the middle 
 of the run of the thread and shorten the rod at the top. 
 This will be found the most satisfactory method, for when 
 all is adjusted the nut will stand in the middle of its scope 
 and have an ^qual run for fast or slow adjustment. With 
 the rod of the full length as given, this pendulum had to be 
 cut at the top about one inch to bring to a minute or two in 
 twenty-four hours, and this left all other points below cor- 
 rected. The pin in the rod should be adjusted the last thing, 
 as this allows the rod to slide on the pin equal distances each 
 way. One inch in the raising or lowering of the frame on 
 the rod will alter the rate for twenty- four hours about 
 eighteen minutes. 
 
 Many attempts have been made to combine the good qual- 
 ities of the various forms of pendulums and thus produce an 
 instrument which would do better work under the severe 
 exactions of astronomical observatories and master clocks 
 controlling large systems. The reader should understand 
 that, just as in watch work, the difficulties increase enor- 
 mously the nearer we get towards absolute accuracy, and 
 
74 THE MODERN CLOCK. 
 
 while anybody can make a pendulum which will stay within 
 a minute a month, it takes a very good one to stay within 
 five seconds per month, under the conditions usually found 
 in a store, and such a performance makes it totally unfit for 
 astronomical work, where variations of not over five-* 
 thousandths of a second per day are demanded. In order 
 to secure such accuracy every possible aid is given to the 
 pendulum. Barometric errors are avoided by enclosing it in 
 an airtight case, provided with an airpump ; the temperature 
 is carefully maintained as nearly constant as possible and its 
 performance is carefully checked against the revolutions of 
 the fixed stars, while various astronomers check their ob- 
 servations against each other by correspondence, so that 
 each can get the rate of his clock by calculations of obser- 
 vations and the law of averages, eliminating personal errors. 
 
 One of the successful attempts at such a combination of 
 mercury and metallic pendulums is that of Riefler, as shown 
 in Fig. 15, which illustrates a seconds pendulum one-thir- 
 tieth of the actual size. 
 
 It consists of a Mannesmann steel tube (rod), bore 16 
 mm., thickness of metal i mm., filled with mercury to 
 about two-thirds of its length, the expansion of the mercury 
 in the tube changing the center of weight an amount suffi- 
 cient to compensate for the lengthening of the tube by 
 heat, or vice versa. The pendulum, has further, 
 a metal bob weighing several kilograms, and shaped to 
 cut the air. Below the bob are disc shaped weights, attached 
 by screw threads, for correcting the compensation, the 
 number of which may be increased or diminished as ap- 
 pears necessary. 
 
 Whereas in the Graham pendulum regulation for tem- 
 perature is effected by altering the height of the column of 
 
THE MODERN CLOCK 
 
 75 
 
 mercury, in this pendulum it is effected by 
 changing the position of the center of 
 weight of the pendulum by moving the 
 regulating weights referred to, and thus 
 the height of the column of mercury always 
 remains the same, except as it is influenced 
 by the temperature. 
 
 A correction of the compensation should 
 be effected, however, only in case the pen- 
 dulum is to show sidereal time, instead of 
 mean solar time, for which latter it is cal- 
 culated. In this case a weight of no to 
 120 grams should be screwed on to correct 
 the compensation. 
 
 In order to calculate the effect of the 
 compensation, it is necessary to know pre- 
 cisely the co-efficients of the expansion by 
 heat of the steel rod, the mercury, and the 
 material of which the bob is made. 
 
 The last two of these co-efficients of ex- 
 pansion are of subordinate importance, the 
 two adjusting screws for shifting the bob 
 up and down being fixed in the middle of 
 the latter. A slight deviation is, therefore, 
 of no consequence. In the calculation for 
 all these pendulums the co-efficient for the 
 bob is, therefore, fixed at 0.000018, and for 
 the mercury at 0.00018136, being the clos- 
 est approximation hitherto found for chem- 
 ically pure mercury, such as that used in 
 these pendulums. 
 The co-efficient of the expansion of the steel rod is, how- 
 ever, of greater importance. It is therefore, ascertained for 
 every pendulum constructed in Mr. Riefler's factory, by the 
 physikalisch-technische Reichsanstalt at Charlottenburg, 
 examinations showing, in the case of a large number of sim- 
 
 Fig. 15. 
 
76 THE MODERN CLOCK. 
 
 ilar steel rods, that the co-efficient of expansion lies be- 
 tween 0.00001034 and 0.00001162. 
 
 The precision with which the measurements are carried 
 out is so great that the error in compensation resulting 
 from a possible deviation from the true value of the co- 
 efficient of expansion, as ascertained by the Reichsanstalt, 
 does not amount to over ± 0.0017; and, as the precision 
 with which the compensation for each pendulum may be 
 calculated absolutely precludes any error of consequence, 
 Mr. Riefler is in a position to guarantee that the probable 
 error of compensation in these pendulums will not exceed 
 ± 0.005 seconds per diem and ± j° variation in tem- 
 perature. 
 
 A subsequent correction of the compensation is, there- 
 fore, superfluous, whereas, with all other pendulums it is 
 necessary, partly because the co-efficients of expansion of 
 the materials used are arbitrarily assumed ; and partly 
 because none of the formulae hitherto employed for calcu- 
 lating the compensation can yield an exact result, for the 
 reason that they neglect to notice certain important influ- 
 ences, in particular that of the weight of the several parts 
 of the pendulum. Such formulae are based on the assump- 
 tion that this problem can be solved by simple geometrical 
 calculation, whereas, its exact solution can be arrived at 
 only with the aid of physics. 
 
 This is hardly the proper place for details concerning 
 the lengthy and rather complicated calculations required 
 by the method employed. It is intended to publish them 
 later, either in some mathematical journal or in a separate 
 pamphlet. Here I will only say that the object of the 
 whole calculation is to find the allowable or requisite weight 
 of the bob, i. e., the weight proportionate to the co-efficients 
 of expansion of the steel rod, dimensions and weight of the 
 rod and the column of mercury being given in each sep- 
 arate case. To this end the relations of all the parts of the 
 
THE MODERN CLOCK. 77 
 
 pendulum, both in regard to statics and inertia, have to be 
 ascertained, and for various temperatures. 
 
 A considerable number of these pendulums have already 
 been constructed, and are now running in astronomical ob- 
 servatories. One of them is in the observatory of the Uni- 
 versity of Chicago, and others are in Europe. The precision 
 of this compensation which was discovered by purely theo- 
 retical computations, has been thoroughly established by the 
 ascertained records of their running at different temper- 
 atures. 
 
 The adjustment of the pendulums, which is, of course, 
 almost wholly without influence on the compensation, can 
 be effected in three different ways: 
 
 (i.) The rough adjustment, by screwing the bob up or 
 down. 
 
 (2.) A finer adjustment, by screwing the correction 
 discs up or down. 
 
 (3.) The finest adjustment, by putting on additional 
 weights. 
 
 These weights are to be placed on a cup attached to a 
 special part of the rod of the pendulum. Their shape and 
 size is such that they can be readily put on or taken off 
 while the pendulum is swinging. Their weight bears a 
 fixed proportion to the static momentum of the pendulum, 
 so that each additional weight imparts to the pendulum, for 
 iwenty-four hours, an acceleration expressed in even sec- 
 onds and parts of seconds, and marked on each weight. 
 
 Each pendulum is accompanied with additional weights 
 of German silver, for a daily acceleration of i second each, 
 and ditto of aluminum for an acceleration of 0.5 and 0.1 
 second respectively. 
 
 A metal clasp attached on the rear side of the clock-case, 
 may be pushed up to hold the pendulum in such a way that 
 it can receive no twisting motion during adjustment. 
 
 Further, a pointer is attached to the lower end of the 
 pendulum, for reading off the arc of oscillation. 
 
78 THE MODERN CLOCK. 
 
 The essential advantages of this pendulum over the mer- 
 curial compensation pendulums are the following : 
 
 (i.) It follows the changes of temperature more rap- 
 idly, because a small amount of mercury is divided over a 
 greater length of pendulum, whereas, in the older ones the 
 entire (and decidedly larger) mass of mercury is situ- 
 ated in a vessel at the lower end of the pendulum rod. 
 
 (2.) For this reason differences in the temperature of 
 the air at different levels have no such disturbing influence 
 on this pendulum as on the others. 
 
 (3.) This pendulum is not so strongly influenced as 
 the others by changes in the atmospheric pressure, because 
 the principal mass of the pendulum has the shape of a lens, 
 and therefore cuts the air easily. 
 
CHAPTER V. 
 
 REGULATIONS, SUSPENSIONS, CRUTCHES AND MINOR POINTS. 
 
 Regulation. — The reader will have noticed that in de- 
 scribing the various forms of seconds pendulums we have 
 specified either eighteen or thirty-six threads to the inch; 
 this is because a revolution of the nut with such a thread 
 gives us a definite proportion of the length of the rod, so 
 that' it means an even number of seconds in twenty-four 
 hours. 
 
 Moving the bob up or down 1-18 inch makes the clock 
 having a seconds pendulum gain or lose in twenty-four 
 hours one minute, hence the selecting definite numbers of 
 threads has for its reason a philosophical standpoint, and is 
 not a matter of convenience and chance, as seems to be the 
 practice with many clockmakers. With a screw of eighteen 
 threads, we shall get one minute change of the clock's 
 rate in twenty-four hours for every turn of the nut, and 
 if the nut is divided into sixty parts at its edge, each of 
 these divisions will make a change of the clock's rate of one 
 second in twenty-four hours. Thus by using a thread 
 having a definite relation to* the length of the rod regu- 
 lating is made comparatively easy, and a clock can be 
 brought to time without delay. Suppose, after comparing 
 your clock for three or four days with some standard, 
 you find it gains twelve seconds per day, then, turning the 
 nut down twelve divisions will bring the rate down to 
 within one second a day in one operation, if the screw is 
 eighteen threads. With the screw thirty-six threads the 
 nut will require moving just the same number of divisions, 
 only the divisions are twice as long as those with the screw 
 of eighteen threads. 
 
 79 
 
8o THE MODERN CLOCK. 
 
 The next thing is the size and weight of the nut. If it is 
 to be placed in the middle of the bob as in Figs. lo, 12 and 
 15, it should project slightly beyond the surface and its 
 diameter will be governed by the thickness of the bob. If 
 Jt is an internal nut, worked by means of a sleeve and disc, 
 as in Fig. 9, the disc . should be of sufficient diameter to 
 make the divisions long enough to be easily read. If the 
 nut is of the class shown in Fig. 5, 6, 7, a nut is most con- 
 venient, I inch in diameter, and cut on its edge into thirty 
 equal divisions, each of which is equal to one second in 
 change of rate in twenty-four hours, if the screw has thirty- 
 six threads to the inch. This gives 3.1416 inches of cir- 
 cumference for the thirty divisions, which makes them long 
 enough to be subdivided if we choose, each division being a 
 little over one-tenth of an inch in length, so that quarter- 
 seconds may be measured or estimated. 
 
 With some pendulums, Fig. 13, the bob rotates on the 
 rod, and is in the form of a cylinder, say 8^ inches long 
 by 25^ inches in diameter, and the bob then acts on its rod 
 as the nut does, and moves up and down when turned, and 
 in this form of bob the divisions are cut on the outside edge 
 of the cover of the bob, and are so long that each one is sub- 
 divided into five or ten smaller divisions, each altering the 
 clock .2 or .1 second per day. 
 
 On the top of the bob turn two deep lines, close to the 
 edge, about 5^ -inch apart, and divide the whole diameter 
 into thirty equal divisions, and subdivide each of the thirty 
 into five, and this will give seconds and fifths of seconds 
 for twenty-four hours. Each even seconds division should 
 be marked heavier than the fraction, and should be marked 
 from one to thirty with figures. Just above the cover on 
 the rod should slide a short tube, friction tight, and to this 
 a light index or hand should be fastened, the point of which 
 just reaches the seconds circle on the bob cover, and thus 
 indicates the division, its number and fraction. The tube 
 slides on the rod because the exact place of the hand can- 
 
THE MODERN CLOCK. 8l 
 
 not be settled until it has been settled by experiment. After 
 this it can be fastened permanently, if thought best, though 
 as described it will be all sufficient. While the bob is being 
 raised or lowered to bring the clock to its rate, the bob 
 might get too far away or too near to the index and neces- 
 sitate its being shifted, and if friction tight this can be read- 
 ily accomplished, and the hand be brought to just coincide 
 with the divisions and look well and be a means of accom- 
 plishing very accurate minute adjustments. 
 
 Suspensions. — Suspensions are of four kinds, cord, wire 
 loop, knife edges and springs. Cords are generally of 
 loosely twisted silk and are seldom found except in the 
 older clocks of French or Swiss construction. They have 
 been entirely displaced in the later makes of European 
 manufactures by a double wire loop, in which the pendu- 
 lum swings from a central eye in the loop, while the loop 
 rocks upon a round stud by means of an eye at each end 
 of the loop. The eyes should all be in planes parallel to the 
 plane of oscillation of the pendulum, otherwise the bob will 
 take an elliptical path instead of oscillating in a plane. They 
 should also be large enough to roll without friction upon 
 the stud and center of the loop, as any slipping or sliding 
 of either will cause them to soon wear out, besides affecting 
 the rate of the pendulum. Properly constructed loops will 
 give practically no friction and make a very free suspension 
 that will last as long as the clock is capable of keeping 
 time, although it seems to be a very weak and flimsy 
 method of construction at first sight. Care should be taken 
 in such cases to keep the bob from turning when regulating 
 the clock, or the effect. upon the pendulum will be the same 
 as if the eyes were not parallel. 
 
 Knife-edge suspensions are also rare now, having been 
 displaced by the spring, as it was found the vibrations were 
 too free and any change in power introduced a circular error 
 (See Fig. 4) by making the long swings in longer time. 
 
82 THE MODERN CLOCK. 
 
 They are still to be found, however, and in repairing clocks 
 containing them the following points should be observed : 
 The upper surface of the stud on which the pendulum 
 swings should carry the knife edge at its highest point, 
 exactly central with the line of centers of the stud, so that 
 when the pendulum hangs at rest the stud shall taper equally 
 on both sides of the center, thus giving equal freedom to 
 both sides of the swing. Care should be taken that the stud 
 is firmly fixed, with the knife edge exactly at right angles 
 to the movement, and also to the back of the case. The sus- 
 pension stud and the block on the rod should be long enough 
 to hold the pendulum firmly in line, as the angle in the top 
 of the rod must be the sole means of keeping the pendu- 
 lum swinging in plane. The student will also perceive the 
 necessity of making the angle occupy the proper position 
 on the rod, especially if the latter be flat. In repairing 
 this suspension it is usual to make the plate, fasten it in 
 place and then drill and file out the hole, as it is easier to 
 get the angles exactly in this way than to complete the 
 plate and then attempt to fasten it in the exact position in 
 which it should be. After fastening the plates in position 
 on the rod, two holes should be drilled, a small one at the 
 apex of the angle (which must be exactly square and true 
 with the rod), and a larger one below it large enough to 
 pass the files easily. The larger hole can then be enlarged 
 to the proper size, filing the angle at the top in such a way 
 that the small hole first drilled forms the groove at the 
 apex of the angle in which the knife edge of the stud shall 
 v/ork when it is completed. Knife-edge suspensions are 
 unfitted for heavy pendulums, as the weight causes the 
 knife edge to work into the groove and cut it, even if the 
 latter oe jeweled. Both the edge and groove should bt 
 hardened and polished. 
 
 Pendulum Suspension Springs. — Next in importance 
 to the pendulum is its suspension spring. This spring 
 
THE MODERN CLOCK. 83 
 
 should be just stiff enough to make the pendulum swing in 
 all its vibrations in the sam.e time ; that is, if the pendulum 
 at one time swung at the bottom of the jar i^ inch each 
 side of the center, and at another time it swung only i inch 
 each side, that the two should be made in exactly one 
 second. The suspension springs are a point in the con- 
 struction of a fine pendulum, that there has been very 
 much theorizing on, but the experiments have never thus far 
 exactly corroborated the theories and there are no definite 
 rules to go by, but every maker holds to that plan and con- 
 struction that gives his particular works the best results. A 
 spring of sufficient strength to materially influence the 
 swing of the pendulum is of course bad, as it necessitates 
 more power to give the pendulum its proper motion and 
 hence there is unnecessary wear on the pallets and escape 
 wheel teeth, and too weak a spring is also bad, as it would 
 not correct any inequalities in the time of swing and would 
 in time break from overloading, as its granular structure 
 would finally change, and rupture of the spring would fol- 
 low. The office of a spring is to sustain the weight without 
 detriment to strength and elasticity, and if so proportioned 
 to the weight as to be just right, it will make the long and 
 short swings of the pendulum of equal duration. When a 
 pendulum hung by a cord or knife edge insttad of a spring 
 is regulated to mean time and swings just two inches at the 
 bottom, any change in the power that swings the pendu- 
 lum will increase its movement or decrease it, and in either 
 case the rate will change, but with a proper spring the rate 
 will be constant under like conditions. The action of the 
 spring is this: In the long swings the spring, as it bends, 
 lifts the pendulum bob up a little more than the arc of the 
 normal circle in which it swings, and consequently when 
 the bob descends, in going to the center of its swing, it falls 
 a little quicker than it does when held by a cord, and this 
 extra quick drop can be made to neutralize the extra time 
 taken by the bob in making extra long swings. See Fig. 4. 
 
84 
 
 THE MODERN CLOCK. 
 
 This action is the isochronal action of the spring, the same 
 that is attained in isochronal hair springs in watches. 
 
 As with the hairspring, it is quite necessary that the pen- 
 dulum spring be accurately adjusted to isochronism and my 
 advice to every jeweler is to thoroughly test his regulator, 
 which can easily be done by changing the weight or motive 
 power. If the test should prove the lack of isochronism he 
 can adjust it by following these simple rules. Fig. i6 is the 
 pendulum spring or leaf. If the short arcs should prove the 
 slowest, make the spring a trifle thinner at B ; if fastest, re- 
 duce the thickness of the spring at A. Continue the test 
 until the long and short arcs are equal. In doing this care 
 must be taken to thin each spring equally, if it is a double 
 spring, and each edge equally, if a single spring, as if one 
 side be left thicker than the other the pendulum will wabble. 
 
 The cause of a pendulum wabbling is that there must be 
 something wrong with the suspension spring, or the bridge 
 
 B-A 
 
 a 
 
 Err 
 
 □ E 
 
 Fig, 16. 
 
 that holds the spring. If the suspension spring is bent or 
 kinked, the pendulum will wabble ; or if the spring should 
 be of an unequal thickness it will have the same effect on 
 the pendulum; but the main cause of the pendulum wab- 
 bling in American clocks is that the slot in the bridge that 
 holds the spring, or the slot in the slide that works up and 
 down on the spring (which is used to regulate the clock) is 
 not parallel. When this slot is not parallel it pinches the 
 spring, front or back, and allows it to vibrate more where 
 it is the freest, causing the pendulum to wabble. We have 
 
THE MODERN CLOCK. 85 
 
 found that by making these slots parallel the wabbling of the 
 pendulum has ceased in most all cases. If the pallet staff 
 is not at right angles to the crutch, wabbling may be caused 
 by the oblique action of the crutch. This often happens 
 when the movement is not set square in the case. 
 
 It occasionally happens in mantel clocks that the pendu- 
 lum when brought to time is just too long for the case when 
 too thick a spring is used. In such a case thinning the 
 spring will require the bob to be raised a little and also 
 give a better motion. If compelled to make a spring use 
 a piece of mainspring about .007 thick and ^ wide for 
 small pendulums and the same spring doubled for heavier 
 pendulums, making the acting part of the spring about 1.5 
 inches long. 
 
 The suspension spring for a rather heavy pendulum is 
 better divided, that is, two springs, held by two sets of 
 clamps, and jointly acting as one spring. The length will 
 be the same as to the acting part, and that part held at each 
 end by the clamps may be ^ inch long; total length, 1.5 
 inches with ^ inch at each end held in the clamps. These 
 clamps are best soldered on to the spring with very low 
 flowing solder so as not to draw the temper of the spring, 
 and then two rivets put through the whole, near the lower 
 edge of the clamps. The object of securing the clamps 
 so firmly is so that the spring may not bend beyond the 
 edge of the clamps, as if this should take place the clock will 
 be thrown off of its rate. After a time the rate would 
 settle and become steady, but it only causes an extra period 
 of regulating that does not occur when the clamps hold 
 the spring immovable at this point. About in the center of 
 each of the clamps, when soldered and riveted, is to be a 
 hole bored for a pin, which pins the clamp into the bracket 
 and holds the weight of the pendulum. 
 
 The width of this compound spring for a seconds' pendu- 
 lum of average weight may be .60 inch, from outside to 
 outside, each spring .15 inch wide. This will separate the 
 
86 
 
 THE MODERN CLOCK. 
 
 Springs .30 inch in the center. With this form of spring, 
 the lower end of each spring being held in a pair of clamps, 
 the clamps will have to be let into the top of the roa, and 
 held in by a stout pin, or the pendulum finished with a hook 
 which will fit the clamp. In letting the clamp into the 
 rod, the clamp should just go into the mortise and be with- 
 out side shake, but tilt each way from the center a little 
 on the pin, so that when the pendulum is hung it may hang 
 perpendicular, directly in the center of both springs. Also, 
 the top pair of clamps should fit into a bracket without 
 shake, and tilt a little on a pin, the same as the lower clamps. 
 These two points, each moving a little, helps to take any 
 side twist away, and allows the whole mechanism to swing 
 in line with the center of gravity of the mass from end to 
 end. With the parts well made, as described, the bob will 
 swing in a straight line from side to side, and its path will 
 be without any other motion except the one of slight curva- 
 ture, due to being suspended by a fixed point at the upper 
 clamp. 
 
 Pendulum Supports. — Stability in the movement and in 
 the suspension of the pendulum is very necessary in all 
 forms of clocks for accurate time-keeping. The pendulum 
 should be hung on a bracket attached to the back of the 
 case (see Fig. 6), and not be subject to disturbance when 
 the movement is cleaned. Also the movement should rest 
 on two brackets attached to the bracket holding the pendu- 
 lum and the whole be very firmly secured to the back board 
 of the case. Screws should go through the foot-pieces of 
 the brackets and into a stone or brick wall and be very 
 firmly held against the wall just back of the brackets. Any 
 instability in this part of a clock is very productive of poor 
 rates. The bracket, to be in its best form, is made of cast 
 iron, with a large foot carrying all three separate brackets, 
 well screwed to a strong back-board and the whole secured 
 to the masonry by bolts. Too much firmness cannot be 
 
THE MODERN CLOCK. 87 
 
 attained, as a lack of it is a. very great fault, and many a 
 good clock is a very poor time-keeper, due to a lack of firm- 
 ness in its supports and fastenings. The late Edward How- 
 ard used to make his astronomical clocks with a heavy cast 
 iron back, to which the rest of the case was screwed, so 
 that the pendulum should not swing the case. Any external 
 influence that vibrates a wall or foundation on which a clock 
 is placed, is a disturbing influence, but an instability in a 
 clock's attachment to such supports is a greater one. Many 
 pendulums swing the case in which they hang (from un- 
 stable setting up) and never get down to or maintain a 
 satisfactory rate from that cause. This is also aggra- 
 vated by the habit of placing grandfather clocks on stair 
 landings or other places subject to jarring. The writer 
 knows of several clocks which, after being cleaned, kept 
 stopping until raised off the floor and bolted to the wall, 
 when they at once took an excellent rate. The appearance 
 of resting on the floor may be preserved, if desirable, by 
 raising the' clock only half an inch or so, just enough to 
 free it from the floor. 
 
 Crutches. — The impulse is transmitted to the pendulum 
 from the pallet staff by means of a wire, or slender rod, 
 fastened at its upper end to the pallet staff and having its 
 lower end terminating in a fork (crutch), loop, or bent 
 at right angles so as to work freely in a slot in the rod. 
 It is also called the verge w^re, owing to the fact that older 
 writers and many of the older workmen called the pallet 
 fork the verge, thus continuing the older nomenclature, 
 although of necessity the verge disappeared when the crown 
 wheel was discarded. 
 
 In order to avoid friction at this very important point, 
 the centers of both axes of oscillation, that of the pallet 
 arbor and fet of the pendulum spring, where it bends, 
 should be in a straight horizontal line. If, for instance, the 
 center of suspension of the pendulum be higher, then the 
 
88 THE MODERN CLOCK. 
 
 fork and the pendulum describe two different arcs of circles ; 
 that of the pendulum will be greater than that of the fork 
 at their meeting point. If, however, the center of suspen- 
 sion of the pendulum be lower than that of the fork, they 
 will also describe two different arcs, and that of the pendu- 
 lum will be smaller than that of the fork at their point of 
 meeting. This, as can be readily understood, will cause 
 friction in the fork, the pendulum going up and down in it. 
 This is prevented when, as stated before, the center of sus- 
 pension of the pendulum is in the prolonged straight imagin- 
 ary line going through the center of the pivots of the fork, 
 which will cause the arcs described by the fork and the pen- 
 dulum to be the same. It will be well understood from the 
 foregoing that the pendulum should neither be suspended 
 higher nor lower, nor to the left, nor to the right of the 
 fork. 
 
 If the centers of motion do not coincide, as is often the 
 case with cheap clocks with recoil escapements, any rough- 
 ness of the pendulum rod where it slides on the crutch 
 will stop the clock, and repairers should always see to it 
 that this point is made as smooth as possible and be very 
 slightly oiled when setting up. If putting in a new verge 
 wire, the workman can always tell where to bend it to form 
 the loop by noticing where the rod is worn and forming the 
 loop so that it will reach the center of that old crutch or 
 loop mark on the pendulum rod. If the verge wire is too 
 long, it will give too great an arc to the pendulum if the 
 latter is hung below the pallet arbor, as is generally the case 
 with recoil escapements of the cheap clocks, and if it is too 
 short there will not be sufficient power applied to the pendu- 
 lum when the clock gets dirty and the oil dries, in which 
 case the clock will stop before the spring runs down. 
 
 An important thing to look after when repairing is in the 
 verge wire -and loop (the slot the pendulum rod goes 
 through). After the clock is set up and oiled, put it on a 
 level shelf; have a special adjusted shelf for this level ad- 
 
THE MODERN CLOCK. S9 
 
 justing, one that is absolutely correct. Have the dial off. 
 If the beat is off on one side, so that it bangs up heavily on 
 one side of the escape wheel, bend the verge wire the same 
 way. That will reverse the action and put it in beat. 
 So far so good — but don't stop now. Just notice whether 
 if that shelf were tipped forward or back, as perhaps your 
 customer's may, that the pendulum should still hang plumb 
 and free. Now if the top of your clock tips forward, the 
 pendulum ball inclines to hang out toward the front. We 
 will suppose you put two small wedges under the back of the 
 case. Now notice in its hanging out whether the pendulum 
 rod pinches or bears in the throat of the verge ; or if it tips 
 back, see if the rod hits the other end of the slot. This 
 verge slot should be long enough, with the rod hanging in 
 the middle when adjusted to beat on a level, to admit of the 
 clock pitching forward or back a little without creating a 
 friction on the ends of the slot. This little loop should 
 be open just enough to be nice and free; if open too much, 
 you will notice the pallet fork will make a little jump when 
 carrying the ball over by hand. This is lost motion. If this 
 little bend of wire is not parallel it may be opened enough 
 inside, but if pitched forward a little it will bind in the nar- 
 rowest part of the V and then the clock will stop. The clock 
 beat and the tipping out or in of the clock case, causing a 
 binding or bearing of the pendulum rod in this verge throat, 
 does more towards stopping clocks just repaired than all 
 other causes. 
 
 Putting in Beat. — To put a clock in beat, hang the clock 
 in such a position that when the pendulum is at rest one 
 tooth of the escape wheel will rest on the center of a pallet 
 stone. Screwed on the case of the clock at the bottom of 
 the pendulum there is, or should be, an index marked with 
 degrees. Now, while the escape-wheel tooth is resting on 
 the pallet, as explained above, the index of the pendulum 
 should point to zero on the index. Move the pendulum until 
 
90 
 
 THE MODERN CLOCK. 
 
 the tooth just escapes and note how many degrees beyond 
 zero the pendulum point is. Say it escapes 2° to the left; 
 now move the pendulum until the next tooth escapes — it 
 should escape 2° to the right. But let us suppose it does not 
 ■escape until the index of the pendulum registers 5° to the 
 right of zero. In this case the rod attached to the pallets 
 must be bent until the escape wheel teeth escape when the 
 pendulum is moved an even number of degrees to the right 
 and left of zero, when the clock will be in beat. 
 
 Close Rating with Shot. — V^ery close rating of a sec- 
 onds' pendulum, accompanied by records in the book, may 
 be got with the nut alone, but there is the inconvenience of 
 stopping the clock to make an alteration. This may be avoid- 
 ed by having a small cup the size of a thimble or small pill 
 box on the pendulum top. This can be lifted off and put 
 back without disturbing the motion of the pendulum. In 
 using it a number of small shot, selected of equal size, are 
 put in, say 60, and the clock brought as nearly as possible 
 to time by the nut. After a few days the cup may be 
 emptied and put back, when on further trial the value of the 
 60 shot in seconds a day will be found. This value divided 
 by 60 will give the value of a single shot, by knowing which 
 very small alterations of rate may be made with a definite 
 approach towards accuracy, and in much less time than by 
 putting in or taking out one or more shot at random. 
 
CHAPTER VI. 
 
 TORSION PENDULUMS FOR FOUR HUNDRED DAY CLOCKS. 
 
 As this pendulum is only found in the 400-day, or annual 
 wind, or anniversary clocks (they are known by all of these 
 names), it is best to describe the pendulum and movement 
 together, as its relations to the work to be done may be 
 more easily perceived. 
 
 Rotating pendulums of this ki|id — that is, in which the 
 bob rotates by the twisting of the suspension rod or spring 
 — will not bear comparison with vibrating pendulums for ac- 
 curate time keeping. They are only used when a long 
 period between windings is required. Small clocks to go 
 for twelve months with one winding have the torsion pen- 
 dulum ribbons of flat steel about six inches long, making 15 
 beats per minute. The time occupied in the beat of such a 
 pendulum depends on the power of the suspending ribbon 
 to resist twisting, and the weight and distance from the 
 center of motion of the bob. In fact, the action of the 
 bob and suspending ribbon is very analogous to that of a 
 balance and balance spring. 
 
 In order to get good time from a clock of this character, 
 it should be made with a dead-beat escapement. With such 
 an escapement there is no motion of the escape wheel, after 
 the tooth drops on the locking face of the pallet ; the escape 
 wheel is dead and does not move again until it starts to 
 give the pallet impulse. This style of an escapement allows 
 the pendulum as much freedom to vibrate as possible, as 
 the fork in one form of this escapement may leave the 
 pallet pin as soon as the latter strikes the guard pins, as 
 in the ordinary lever escapement of a watch, and it will 
 remain in that position until the return of the fork unlocks 
 
 91 
 
93 
 
 THE MODERN CLOCK. 
 
 the escapement to receive another impulse. B, Fig. 17, 
 represents the escape wheel; C, the pallet; E, pallet staff; 
 D, the pallet pin rivetted on to the pallet staff E, which 
 works in the slot or fork H; this fork is screwed fast to 
 
 in 
 
 L 
 
 !=ii;iuMfj%Miii,m ^: — iMnmfi pi, i ,m i i => 
 
 Fig. 17. 
 
 the spring. The spring G is made of a piece of flat steel 
 wire and looks like a clock hairspring straightened out. G 
 is fast to the collar I and rests on a seat screwed to the 
 plate of the clock, as shown at P ; the spring is also fast- 
 ened to the pendulum ball O with screw?; the ball makes 
 
THE MODERN CLOCK, 
 
 93 
 
 about one and one-half revolutions each beat, which causes 
 the spring to twist. It twists more at the point S than it 
 does at L; as it twists at L it carries the fork with it, so 
 that the latter vibrates from one side to the other^ similar 
 to a fork in a watch. This fork H carries the pin D, which 
 is fast to the pallet staff E, far enough to allow the teeth 
 to escape. 
 
 Fig. 18. 
 
 In the most common form of this escapement, see Fig. 
 1 8, the fork does not allow the pin D to leave the slot H, 
 and the beat pins are absent, the pendulum not being as 
 highly detached as in the form previously mentioned. In 
 this case great care must be taken to have the edges of the 
 slot, which slide on the pallet pin, smooth, parallel and 
 properly beveled, so as not to bind on the pin. The pen- 
 dulum ball makes from eight to sixteen vibrations a min- 
 ute. Of course the number depends upon the train of the 
 clock. 
 
 In suspending the pendulum it is necessary to verify the 
 drop of the teeth of the escape wheel as follows : The pen- 
 dulum is suspended and the locking position of the pallets 
 
94 
 
 THE MODERN CLOCK. 
 
 marked, taking as a guiding point the long, regulating 
 screw, which, fixed transversely in the support, serves for 
 adjusting the small suspension block. An impulse of about 
 a third of a turn is given to the pendulum while observing 
 the escap'ement. If -the oscillations of the pendulum, meas- 
 ured on the two sides, taking the locking point as the base, 
 are symmetrical, the drop is also equal, and the rate of the 
 clock regular and exact ; but if the teeth of the escape wheel 
 are unlocked sooner on one side than on the other, so that 
 the pendulum in its swing passes beyond the symmetrical 
 
 Fig. 19. 
 
 point on one of the pallets and does not reach it on the 
 other, it is necessary to correct the unequal drop. 
 
 The suspension block B, .Fig. i8, between the jaws of 
 which the steel ribbon is pressed by two screw^s, has a lower 
 cylindrical portion, which is fitted in a hole made in the 
 seat, and is kept immovable by the screw A. If the vibra- 
 tion of the pendulum passes beyond the proper point on the 
 left side, it is necessary to loosen A and turn the sus- 
 pension block slightly to the right. If the deviation is 
 produced in the opposite direction, it is necessary to turn 
 
THE MODERN CLOCK, 
 
 95 
 
 it to the left. These corrections should be repeated until 
 the drop of the escape wheel teeth on the pallets is exactly 
 equal on the two sides. As the drop is often disturbed by 
 the fact that the long thin steel ribbon has been twisted 
 in cleaning, taking apart or handling by unskilled persons 
 before coming to the watchmaker, it is desirable to test the 
 escapement again, when the clock is put into position on 
 the premises of the buyer. 
 
 The timing adjustment of the pendulum is effected with 
 the aid of regulating weights, placed on the ball. By mov- 
 ing these away from the center by means of a right and 
 left hand screw on the center of the disk (see Fig. 19), 
 
 Fig. 20. 
 
 the centrifugal force is augmented, the oscillations .of the 
 pendulum slackened, and the clock goes slower. The con- 
 trary effect is produced if the weights are brought nearer 
 the center. In one form of ball the shifting of the regu- 
 lating weights is accomplished by a compensating spring of 
 steel and brass like the rim of a watch balance. Fig. 20. 
 
 If necessary to replace the pendulum spring, the adjust- 
 ment is commenced by shortening or lengthening the steel 
 ribbon to a certain extent. For this purpose the end of 
 the spring is allowed to project above the suspension block 
 as a reserve until adjustment has been completed, when it 
 may be cut off. If the space between the ball and the bot- 
 tom of the case, or the bottom of the movement plates, does 
 
g6 THE MODERN CLOCK. 
 
 not allow of attaining this end, it is necessary to increase 
 or decrease the weight of the disk, adding one or several 
 plates of metal in a depression made in the under side of 
 the ball, and removing the plates screwed to it, which are 
 too light. 
 
 There are some peculiarities of the trains of these clocks. 
 The cannon pinion is provided with a re-enforcing spring, 
 serving as guide to the dial work, on which it exercises a 
 sufficient pressure to assure precise working. The pressure 
 of this spring is important, because if the dial work presses 
 too hard on the pinion of the minute wheel, the latter en- 
 gaging directly with the escape wheel, would transmit to the 
 latter all the force employed in setting the hands. The 
 teeth of the escape wheel would incur damage and the con- 
 sequent irregularity or even stopping of the clock would 
 naturally follow. 
 
 In order that it may run for so long a time, the motive 
 force is transmitted through the train by the intervention 
 of three supplementary wheels between the minute wheel 
 and the barrel, in order to avoid the employment of too large 
 a barrel; the third wheel is omitted; the motion work is 
 geared immediately with the arbor of the escape wheel. 
 It is evident that the system of the three intermediate 
 wheels, of which we have spoken, requires for the motive 
 force a barrel spring much stronger than that of ordinary 
 clocks. 
 
 The points which we have noticed are of the most im- 
 portanc-e with reference to the repair and keeping in order 
 of an annual clock. It very often happens that when the 
 repairer does not understand these clocks, irregularities are 
 sought for where they do not exist. The pivot holes are 
 bushed and the depthings altered, when a more intelligent 
 examination would show that the stopping, or the irregular 
 rate of the clock, proceeds only from the condition of the 
 escapement. Unless, however, they are perfectly adjusted, 
 
THE MODERN CLOCK. 97 
 
 a variation of five minutes a week is a close rate for them, 
 and most of those in use will vary still more. 
 
 Annual clocks are enjoying an increased favor with the 
 public; their good qualities allow confidence, the rate being 
 quite regular when in proper order. They are suitable for 
 offices ; their silent running recommends them for the sick 
 chamber, and the subdued elegance of their decoration 
 causes the best of them to be valued ornaments in the home. 
 
-gahd e: Loo^ ih 
 
 i^i2u't:ikRirit§''m 'AnGVtLkR MEAsuREMEWt— lidw'-- Tcf-^^^i) 
 iv'^- DRAWINGS. .i^cirriGd:) 
 
 "'We now come to a point at which, if we are to keep our 
 pendulum vibrating, we must apply power to it, evenly, ac- 
 curately and in small doses. In order to do this convenient- 
 ly we must store up energy by raising a weight or winding 
 a spring and allow the weight to fall or the spring to un- 
 wind very slowly, say in thirty hours or in eight days. This 
 brings about the necessity of changing rotary motion to 
 reciprocating motion, and the several devices for doing this 
 are called "escapements" in horology, each being further 
 designated by the names of their inventors, or by some 
 peculiarity of the devices themselves ; thus, the Graham is 
 also called the dead beat escapement; Lepaute's is the pin 
 wheel; Dennison's in its various forms is called the gravity; 
 Hooke's is known as the recoil ; Brocot's as the visible 
 escapement, etc. 
 
 The Mechanical Elements. — We shall understand this 
 subject more clearly, perhaps, if we first separate these 
 mechanical devices into their component parts and consider 
 them, not as parts of clocks, but as various forms of levers, 
 which they really are. This is perhaps the best place to- 
 consider the levers we are using to transmit the energy 
 to the pendulum, as at this point we shall find a greater va- 
 riety of forms of the lever than in any other place in the 
 clock, and we shall have less difficulty in understanding the 
 methods of calculating for time and power by a thorough 
 preliminary understanding of leverage and the peculiarities 
 of angular or circular motion. 
 
 9S 
 
THE MODERN CLOCK. 
 
 99 
 
 If we take a bar, A, Fig. 21, and place under it a ful- 
 crum, B, then by applying at C a given force, we shall be 
 able to lift at D a weight whose amount will be governed 
 by the relative distances of C and D from the fulcrum B. 
 
 C 
 
 Fig. 21. 
 
 If the distance CB is four times that of BD, then a force 
 of 10 pounds at C will lift 40 pounds at D, for one-fourth 
 of the distance through which C moves, minus the power 
 lost by friction. The reverse of this is also true; that is, 
 it will take 40 pounds at D to exert a force of 10 pounds 
 
 - Fig. 22. 
 
 at C and the 10 pounds would be lifted four times as far 
 as the 40 pound weight was depressed. 
 
 If instead of a weight we substitute other levers. Fig. 22, 
 the result would be the same, except that we should move 
 the other levers until the ends which were in contact 
 slipped apart. 
 
 II 
 ^ ' J A 
 
 ^D 
 
 Fig. 23. 
 
 If we divide our lever and attach the long end to one 
 portion of an axle, as at A, Fig. 23, and the short end to 
 another part of it at B, the result will be the same as long 
 
lOO THE MODERN CLOCK. 
 
 as the proportions of the lever are not changed. It will 
 still transmit power or impart motion according to the 
 relative lengths of the two parts of the lever. The capacity 
 of our levers, Fig. 22, will be limited by that point at which 
 the ends of the levers will separate, because they are held 
 at the points of the fulcrums and constrained to move in 
 circles by the fulcrums. If we put more levers on the 
 same axles, so spaced that another set will come into action 
 as the first pair are disengaged, we can continue our trans- 
 mission of power. Fig. 24; and if we follow this with still 
 
 Fig. 24. 
 
 others until we can add no more for want of room we shall 
 have wheels and pinions, the collection of short levers form- 
 ing the pinion and the group of long levers forming the 
 wheel, Fig. 25. Thus every wheel and pinion mounted to- 
 gether on an arbor are simply a collection of levers, each 
 wheel tooth and its corresponding pinion leaf forming one 
 lever. This explains why the force decreases and the mo- 
 tion increases in proportion to the relative lengths of the 
 radii of the wheels and pinions, so that eight or ten turns of 
 the barrel of a clock will run the escape wheel all day. 
 
 We now come to the verge or anchor, and here we have 
 the same sort of lever in a different form; the verge wire, 
 which presses on the pendulum rod and keeps it going is 
 the long arm of our lever, but instead of many there is only 
 one. The short arm of our lever is the pallet, and there 
 are two of these. Therefore we have a form of lever in 
 which there is one long arm and two short ones ; but as the 
 two are never acting at the same time they do not interfere 
 with each other. 
 
TJIE MODERN CLOCK. 
 
 Ol 
 
 These systems of levers have another advantage, which 
 is that one arrri need not be on the opposite side of the ful- 
 
 ff 
 
 Fii-. 25. 
 
 crum from the other. It may be on the same side as in the 
 verge or at any other convenient point. This enables us 
 to save space in arranging our trains, as such a collection 
 
I02 THE MODERN CLOCK. 
 
 of wheels and pinions is called, by placing them in any ,po- 
 sition which, on account of other facts, may seem desirable. 
 
 Peculiarities of Angular Motion. — Now our collec- 
 tions of levers must move in certain directions in order to 
 be serviceable and in order to describe these things prop- 
 erly, we must have names for these movements so that we 
 can convey our thoughts to each othei'. Let us see how 
 they move. They will not move vertically (up or down) 
 or horizontally (sidewise), because we have taken great 
 pains to prevent them from doing so by confining the cen- 
 tral bars of our levers in a fixed position by making pivots 
 on their ends and fitting them carefully into pivot holes in 
 the plates, so that they can move only in one plane, and 
 that movement must be in a circular direction in that pre- 
 determined plane. Consequently we must designate any 
 movement in terms of the portions of a circle, because that 
 is the only way they can move. 
 
 These portions of a circle are called angles, which is a 
 general term meaning always a portion of a circle, meas- 
 ured from its center ; this will perhaps be plainer if we con- 
 sider that whenever we want to be specific in mentioning 
 any particular size of angle we must speak of it in degrees, 
 minutes and seconds, which are the names of the standard 
 parts into which a circle is divided. Now in every circle, 
 large or small, there are 360 degrees, because a degree is 
 I -360th part of a circle, and this measurement is always 
 from its center. Consequently a degree, or any angle com- 
 posed of a number of degrees, is always the same, because, 
 being measured from its center, such measurements of any 
 two circles will coincide as far as they go. If we draw 
 two circles having their centers over each other at A, Fig. 
 26, and take a tenth part of each, we shall have 36o°-^-io:= 
 36°, which we shall mark out by drawing radial lines to 
 the circumference of each circle, and we shall find this to 
 be true: the radii of the smaller circle AB and AC will 
 
THE MODERN CLOCK. 
 
 103 
 
 coincide M^ith the radii AD and AE as far as they go. This 
 is because each is the tenth part of its circle, measured from 
 its center. Now that portion of the circumference of the 
 circle BC will be smaller than the same portion DE of the 
 larger circle, but each will be a tenth part of its ozvn circle, 
 although they are not the same size when measured by a 
 rule on the circumference. This is a point which has 
 bothered so many people w^hen taking up the study of an- 
 gular measurement that we have tried to make it absurdly 
 
 
 clear. An angle never means so many feet, inches or 
 millimeters ; it always means a portion of a circle, measured 
 from the center. ^ v ,ji":^i 
 
 There is one feature about these angular (of circular) 
 measurements that is of great convenience, which is that 
 as no definite size is mentioned, but only proportionate 
 sizes, the description of the machine described need not be 
 changed for any size desired, as it will fit all sizes. It thus 
 becomes a flexible term, like the fraction ''one-half," chang- 
 ing its size to suit the occasion. Thus, one-half of 300,000 
 bushels of wheat is 150,000 bushels; one-half of 10 bush- 
 els is 5 bushels ; one-half of one bushel is two pecks ; yet 
 each is one-half. It is so with our angles. 
 
 There are some other terms which we shall do well to 
 investigate before we leave the subject of angular meas- 
 
I04 
 
 THE MODERN CLOCK. 
 
 urements, which are the relations between the straight and 
 curved lines we shall need to study in our drawings of the 
 various escapements. A radius (plural radii) is a straight 
 line drawn from the center of a circle to its circumference. 
 A tangent is a straight line drawn outside the circum- 
 ference, touching (but not cutting) it at right angles (90 
 degrees) to a radius drawn to the point of tangency (point 
 where it touches the circumference). A general misun- 
 derstanding of this term (tangent) has done much to hinder 
 a proper comprehension of the writers who have attempted 
 to make clear the mysteries of the escapements. Its im- 
 portance will be seen when we recollect that about the first 
 thing we do in laying out an escapement is to draw tangents 
 to the pitch circle of the escape wheel and plant our pallet 
 center where these tangents intersect on the line of cen- 
 ters. They should always be drawn at right angles to the 
 radii which mark the angles we choose for the working 
 portion of our escape wheel. If properly drawn we shall 
 find that the pallet arbor will then locate itself at the cor- 
 rect distance from the escape wheel center for any desired 
 angle of escapement. We shall also discover that it will 
 take a different center distance for every different angle 
 and yet each different position will be the correct one for 
 its angle, Fig. 27. 
 
 Because an angle is always the same, no matter how far 
 from the center the radii defining it are carried, we are 
 able to work conveniently with large drawing instruments 
 on small drawings. Thus we can use an eight or ten inch 
 protractor in laying off our angles, so as to get the degrees 
 large enough to measure accurately, mark the degrees with 
 dots on our paper and then draw our lines with a straight 
 edge from the center towards the dots, as far as we wish 
 to go. Thus we can lay off the angles on a one-inch 
 escape wheel with a ten-inch protractor more easily and 
 correctly than if we were using a smaller instrument. 
 
THE MODERN CLOCK. I05 
 
 
 
 lA 
 
 
 
 
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 / 1 \ 
 
 
 
 
 T/ 1 \ 
 
 
 
 
 / : V 
 
 
 
 
 / 'N ^ 
 
 
 
 
 
 
 
 
 / / ^'^- ^ ^^ 
 
 
 
 
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 //;cin''t-~->^>.\\ 
 
 
 
 / 
 
 / ■i!'\ \ ' / >'^-^. \ 
 
 
 
 
 
 
 ^ s 
 
 \ \ \ , ' / / ^ \ 
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 ^ \ \ \ i / / / / A 
 
 
 / 
 
 s 
 
 
 
 
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 \ 
 \ 
 
 
 
 
 
 ^v^- 
 
 I 
 
 1 
 
 \ 
 
 
 
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 \P 
 
 
 
 / 
 
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 \ 
 
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 \ 
 
 V 
 
 ! 
 
 
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 ! 
 
 I 
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 IB 
 
 Fig. 27, 
 
I06 THE MODERN CLOCK. 
 
 Another thing which will help us in understanding these 
 drawings is that the effective length of a lever is its dis- 
 tance from the center to the working point, measured in 
 a straight line. Thus in a pallet of a clock the distance 
 of the pallets from the center of the pallet arbor is the 
 effective length of that arm of the lever, no matter how 
 it may be curved for ornament or for other reasons. 
 
 The lines and circles drawn to enable us to take the 
 necessary measurements of angles and center distances are 
 called "'construction lines" and are generally dotted on 
 the paper to enable us to distinguish them as lines for 
 measurement only, while the lines which are intended to 
 define the actual shapes of the pieces thus drawn are solid 
 lines. By observing this distinction we are enabled to 
 show the actual shapes of the objects and all their angular 
 measurements clearly on the one drawing. 
 
 With these explanations the student should be able to 
 read clearly and correctly the many drawings which fol- 
 low, and we will now turn our attention to the escape- 
 ments. In doing this we shall meet with a constant use 
 of certain terms which have a peculiar and special mean- 
 ing when applied to escapements. 
 
 The Lift is the amount of angular motion imparted to 
 the verge or anchor by the teeth of the escape wheel press- 
 ing against the pallets and pushing first one and then the 
 other out of the way, so that the escape wheel teeth may 
 pass. According as the angular motion is more or less 
 the "Hft" is said to be greater or less; as this motion is 
 circular, it must be expressed in degrees. The lifting 
 planes are those surfaces which produce this motion; in 
 clocks with pendulums the lifting planes are generally on 
 the pallets, being those hard and smoothly polished sur- 
 faces over which the points of the escape wheel teeth slide 
 in escaping. In lever escapements the lifting planes are 
 frequently on the escape wheel, the pallets being merely 
 
THE MODERN CLOCK. 
 
 07 
 
 round pins. Such an escape wheel is said to have club 
 teeth, as distinguished from the pointed teeth used when 
 the Hfting planes are on the pallets. In the cylinder 
 escapement the lifting planes are on the escape wheel; 
 they are curved instead of being straight; and there is but 
 one pallet, which is on the lip of the cylinder. In the 
 forms of lever escapement used in watches and some 
 clocks the lift is divided, part of the lifting planes being 
 also on the pallets; in this case both sets of planes are 
 shorter than if they were entirely on one or the other, but 
 they must be long enough so that combined they will pro- 
 duce the requisite amount of angular motion of the pallets, 
 so as to give the requisite impulse to the pendulum or bal- 
 ance. 
 
 The Drop is the amount of circular motion, measured 
 in degrees, which the escape wheel has from the instant 
 the tooth escapes from one pallet to that point at which it 
 is stopped by the other pallet catching another tooth. Dur- 
 ing this period the train is running down without impart- 
 ing any power to the pendulum or balance, hence the drop 
 is entirely lost motion. We must have it, however, as it 
 requires some time for the other pallet to move far enough 
 within the pitch circle of the escape wheel to safely catch 
 and stop the next tooth under all circumstances. It is the 
 freedom and safety of the working plan of our escape- 
 ment, but it is advisable to keep the drop as small as is 
 possible with safe locking. 
 
 The Lock is also angular motion and is measured in 
 degrees from the center of the pallet arbor. It is the 
 distance which the pallet has moved inside of the pitch 
 circle of the escape wheel before being struck by the escape 
 wheel tooth. It is measured from the edge of the lifting 
 plane to the point of the tooth where it rests on the lock- 
 ing face of the pallet. A safe lock is necessary in order 
 
I08 THE MODERN CLOCK. 
 
 to prevent the points of the escape wheel teeth butting 
 against the lifting planes, stopping the clock and injuring 
 the teeth. We want to point out that from the instant 
 of escaping to the instant of locking we have the two parts 
 of our escapement propelled by different and entirely sep- 
 arate forces and moving at different speeds. The pallets, 
 after having given impulse to the pendulum, are controlled 
 by the pendulum and moved by it; in the case of a heavy 
 pendulum ball at the end of a 40-inch lever, this control 
 is very steady, powerful and quite slow. The escape 
 wheel, the lightest and fastest in the train, is driven by 
 the weight or spring and moves independently of the 
 pallets during the drop, so that safe locking is important. 
 It should never be too deep, as it would increase the swing 
 of the pendulum too much; this is especially true with 
 short and light pendulums and strong mainsprings. 
 
 The Run. — After locking the pallet continues to move 
 inward towards the escape wheel center as the pendulum 
 continues its course, and the amount of this motion, meas- 
 ured in degrees from the center of the pallet arbor, is 
 called the run. 
 
 When the escapement is properly adjusted the lifting 
 planes are of the same length on both pallets, when they 
 are measured in degrees of motion given to the pallet ar- 
 bor. They may or may not be equal in length when 
 measured by a rule on the faces of the pallets. There 
 should also be an equal and safe lock on each pallet, as 
 measured in degrees of movement of the pallet arbor. 
 The run should also be equal. 
 
 The reason why one lifting plane may be longer than 
 the other and still give the same amount of lift is that 
 some escapements are constructed with unequal lockings, 
 so that one radius is longer than the other, and this, as 
 we explained at length in treating of angles. Fig. 26, would 
 make a difference in the length of arc traversed by the 
 longer arm for the same angle of motion. 
 
CHAPTER VIII. 
 
 THE GRAHAM OR DEAD BEAT ESCAPEMENT. 
 
 This escapement is so called because the escape wheel 
 remains "dead" (motionless) during the periods between 
 the impulses given to the pendulum. It is the original or 
 predecessor of the well known detached lever escapement 
 so common in watches, and it is surprising how many 
 watchmakers who are fairly well posted on the latter form 
 exhibit a surprising ignorance of this escapement as used 
 in clocks. It has like the latter a "lock," "lift" and "run" ; 
 the only difference being that it has no "draw," the control 
 by the verge wire rendering the draw unnecessary. 
 
 It may be made to embrace any number of teeth of the 
 escape wheel, but, owing to the peculiarities of angular 
 motion referred to in the last chapter, see Fig. 26, B C, D E, 
 the increased arcs traveled as the pallet arms lengthen in- 
 troduce elements of friction which counterbalance and in 
 some cases exceed the advantage gained by increasing the 
 length of the lever used to propel the pendulum. Similarly, 
 the too short armed escapements were found to cause in- 
 creased difficulty from faulty fitting of the pivots and their 
 holes, and other errors of workmanship, which errors could 
 not be reduced in the same proportion as the arms were 
 shortened, so that it has been determined by practice that a 
 pallet embracing ninety degrees, or one-fourth of the cir- 
 cumference of the escape wheel, offers perhaps the best 
 escapement of this nature that can be made. Therefore the 
 factories generally now make them in this way. But as 
 many clocks are coming in for repair with greater or less 
 5ircs of escapement and the repairers must fix them satis- 
 
 109 
 
no THE MODERN CLOCK. 
 
 factorily, we will begin at the beginning by explaining how 
 to make the escapement of any angle whatever, from one 
 tooth up to 140 degrees, or nearly half of the escape wheel. 
 
 It is quite a common thing for some workmen to imagine 
 that in making an escapement, the pallets ought to take 
 in a given number of teeth, and that the number which they 
 suppose to be right must not be departed from; but there 
 seems to be no rule that necessarily prescribes any number 
 of teeth to be used arbitrarily. The nearer that the center of 
 motion of the pallets is to the center of the escape wheel, the 
 less will be the number of teeth that will be embraced by the 
 pallets. Fig. 28 is an illustration of the distances between 
 the center of motion of the pallets and the center of the 
 wheel required for 3, 5, 7, 9 and 11 teeth in a wheel of the 
 same size as the circle; but although we have adopted 
 these numbers so as to make a symmetrical diagram, any 
 other numbers that may be desirable can be used with equal 
 propriety. All that is necessary to be done to find the 
 proper center of motion of the pallets is first to determine 
 the number of teeth that are to be embraced, and draw 
 lines (radii) from the points of the outside ones of the 
 number to the center of the wheel, and at right angles to 
 these lines draw other two lines (tangents), and the point 
 where they intersect each other on the line of centers will be 
 the center of motion of the pallets. 
 
 It will be seen by the diagram. Fig. 28, that by this 
 method the distance between the centers of motion of the 
 pallets and that of the scape-wheel takes care of itself for a 
 given number of teeth and that it is greater when eleven 
 and one-half teeth are to be embraced than for eight or for 
 a less number. These short pallet arms are imagined by 
 some workmen to be objectionable, on the supposition that 
 it will take a heavier weight to drive the clock; but it can 
 easily be shown that this objection is altogether imaginary. 
 Now, bearing in mind the principles of leverage, if the dis- 
 tance between the pallets and escape wheel centers is very 
 
THE MODERN CLOCK. 
 
 Ill 
 
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112 THE MODERN CLOCK. 
 
 long, as in Graham's plan, in which the pallets embraced 
 138° of the escape wheel, the value of the impulse received 
 from the scape-wheel and communicated through the pallets 
 to the pendulum is no doubt greater with a proper length of 
 verge wire, for, the lifting planes being longer, the leverage 
 is applied to the pendulum for a longer arc of its vibration, 
 yet we must not suppose that from this fact the clock will go 
 
 A 
 
 Fig. 29. Note the diflference ia length of arc for the same angle. 
 
 with less weight, for it is easy to see that the longer the 
 pallet-arms are the greater will be the distance the teeth 
 of the escape wheel will have to move (run) on the circular 
 part of the pallets. See Fig. 29. The extra amount of 
 friction, and the consequent extra amount of resistance 
 offered to the pendulum, caused by the extra distance the 
 points of the teeth run on the circular locking planes of the 
 pallets and back again, destroys all the value of the extra 
 amount of impulse given to the pendulum in the first in- 
 stance by means of the long arms of the pallets. The escape 
 wheel tooth restinjy on the locking plane of the pallet is quite 
 var-able in its effective action, and since it rests on the 
 pallet during a part of each swing of the pendulum and the 
 pendulum is called on to move the pallet back and forth 
 under the tooth, any change in the- friction between the tooth 
 and pallet is felt by the pendulum and when the clock gets 
 
THE MODERN CLOCK. II3 
 
 dirty and the friction between the tooth and pallet is in- 
 creased, the rate of the clock gets slow, as the friction holds 
 the pendulum from moving as fast as it would without 
 friction. Now, as this friction increases by dirt and thick- 
 ening of the oil, all these forms of escapements are subject 
 to changes and so change the clock's rate. An increase of 
 the driving weight, or force of the mainspring, of clocks 
 with dead-beat escapements always tends to make their rate 
 slow, from the action mentioned. 
 
 It is for this reason that moderately short arms are used 
 in clocks having dead-beat escapements of modern con- 
 struction. Most of the first-class modern makeri of astro- 
 nomical clocks only embrace seven and one-half tectli, en a 
 30-tooth wheel, with the centers of motion of the pallets and 
 scape-wheel proportionately nearer, as it can be mathe- 
 maticallv demonstrated that with the pallets embracing an 
 arc of 90° the application of the power to the pendulum is at 
 right angles to the rod and therefore is most effective. 
 
 To Draw the Escapement. — In order to make the mat- 
 ter clearer we show in Fig. 30 the successive stages of 
 drawing an escapement and also the completed work in 
 Figs. 32 and 33 embracing different numbers of teeth. Draw 
 a line, A B, Fig. 30, to serve as a basis for measurements. 
 With a compass draw from some point C on this line a 
 circle to represent the diameter of our escape wheel. Now 
 we shall require to know how many teeth there will be in 
 our escape wheel. There may be 60, 40, 33, 32, 30, or any 
 other number we desire to give it ; seconds pendulums gen- 
 erally have 30 teeth in this wheel, because this allows the 
 second hand to be mounted directly on the escape wheel 
 arbor and thus avoids complications. We divide the number 
 of degrees in a circle (360) by the number of teeth we have 
 selected, say 30. 360 -f- 30 = 12° for each tooth and space. 
 One-fourth of 360° equals 90° and one-fourth of 30 teeth 
 equals seven and one-half teeth ; each tooth equaling 12 
 
"4 
 
 THE MODERN CLOCKo 
 
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 T/' 
 
 
 '\T 
 
 
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 •\ 
 
 
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 iA 
 
 z/ 
 
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 ^^ P 
 
 Fig. 30, 
 
THE MODERN CI>OCK. II5 
 
 degrees, we have 12 X 7 = 84°> which gives us six degrees 
 for drop, to ensure the safety of our actions. 
 
 We now take 90° and, dividing it, set off 45° each side of 
 our center line and draw radii, R, from the center to the cir- 
 cumference of our circle ; this marks the beginnings of our 
 pallets. Now to find our pallet center distance we draw 
 tangents, T (at right angles), from the ends of these radii 
 toward the line of centers. The point where they intersect 
 on the line of centers is the pallet center. 
 
 Now we must determine how much motion we are going 
 to give our pendulum, so that we can give the proper lift to 
 our pallets. Four degrees of swing is usual for a seconds 
 pendulum, so we will take four degrees and, dividing it, give 
 two degrees of lift to each pallet. To do this we draw a line 
 two degrees inside the tangent, T (towards the escape wheel 
 center), from our pallet center on the entering pallet side 
 and another line from the pallet center two degrees outside 
 of the tangent, T, on the exit pallet side. Next, from the 
 pallet center we draw arcs of circles cutting the tangents, 
 T, and the radii, R, where they intersect; this gives us the 
 locking planes on which the teeth of the escape wheel "run" 
 (slide) during the excursions of the pendulum, if the 
 escapement is to have unequal lockings ; if the lockings are 
 to be equidistant (if the pallet arms are to be of equal length) 
 the arc for the entering pallet is drawn three degrees below 
 (outside) the radius, R, while that on the exit pallet is 
 drawn three degrees above (inside) the exit radius. Finally 
 the lifting planes are drawn from the intersection of the arcs 
 of circles struck from the pallet center with their tangents, 
 T, to the lines, marking the limits of the lift, two degrees 
 away. These lifting planes should be at an angle of 60° 
 from the radii, R, and as a tangent is always at right angles 
 (90°) to its radius, they are consequently at 30° to 
 the tangents running to the pallet center. Thus we can 
 measure these angles from either the escape wheel or the 
 pallet center, as may be most convenient. 
 
Il6 THE MODERN CLOCK. 
 
 When making a new pallet fork, it is most convenient to 
 mark out the lifting planes on the steel at 30° from the 
 tangents, T, as we then do not have to bother with the 
 escape wheel further than to get its center distance and the 
 degrees of arc the lifting planes are to embrace. The work- 
 man who is not familiar with this rule is apt to have his 
 ideas upset at first by the angles of inclination toward the 
 center line which the lifting planes will take for different 
 center distances, as owing to the fact that the tangents meet 
 on the center line at different angles for different distances, 
 the lifting planes assume different positions with regard to 
 the center line and he may think that they do not "look 
 
 06.'P''''T'-^^>P:<> 
 
 Fig. 31. 
 
 right." They are right, however, when drawn at 30° to 
 their tangents. Fig. 31 shows several pallets with different 
 arcs arranged in line for purposes of comparison, each being 
 drawn according to the above rule, as measurements with a 
 protractor will show. 
 
 We have now arrived at the complete escapement, having 
 finished our pallets. We have, however, nothing to hold 
 them in position ; they must be rigidly held in position with 
 regard to each other and the escape wheel, consequently we 
 will make a yoke to connect them to the pallet arbor out of 
 the same steel, giving it any desired shape that will not inter- 
 fere with the working of the clock. Two of the most usual 
 forms are shown at Figs. 32 and 33. 
 
THE MODERN CLOCK. 
 
 Fig. 32. 
 
ii8 
 
 THE MODERN CLOCK. 
 
 Fig. 33. 
 
THE MODERN CLOCK. II9 
 
 Let us see how this rule will work in repairs. Suppose 
 we have a clock brought in with the pallet fork missing, 
 and that the movement is one of those in which the pallet 
 arbor is held by adjustable cocks which have been misplaced 
 or lost, so that we don't know the center distance of the 
 pallet arbor and escape wheel. We shall have to make a 
 new part. 
 
 Measure the escape wheel, getting its diameter carefully, 
 take half of this as a radius, and mark out the circle with a 
 fine needle point on some copper, brass or sheet steel, draw- 
 ing the escapement as detailed in Figs. 30 and 32. Then 
 measure carefully the angles made by the tangents with the 
 center line ; take the steel which is to be used in making the 
 pallets and fork ; draw on it a center line ; lay off the 
 tangents and the lift lines ; draw the locking arcs and the 
 lifting planes carefully from the tangents and give the rest 
 of the fork a symmetrical shape. Use needle points to draw 
 with and have your protractor large enough to measure 
 your angles accurately. Then drill or saw out and file to 
 your lines, except on the locking and lifting planes ; leave 
 these large enough to stand grinding or polishing after 
 hardening. Harden ; draw to a straw color and polish the 
 planes. Your verge will fit if it has not warped in harden- 
 ing. If this is the case, soften the center, keeping the heat 
 away from the pallets, and bend or twist the arms until 
 the verge will fit the drawing, when laid on top of it. In 
 grinding the pallets the fork should be mounted on its arbor 
 and the latter held between the centers of a rounding up 
 tool while the grinding is done by a lap in the lathe. This 
 insures that the planes will be parallel to the pallet arbor 
 and hence square with the escape wheel teeth, so that they 
 will not create an end thrust on either escape or pallet 
 arbor. It is also the quickest, easiest and most reliable way 
 of doing the job. When clocks come in with the pallets 
 badly cut ; soften the center of the fork, place the ends be- 
 tween the jaws of a vise, squeeze enough to bring them 
 
I20 
 
 THE MODERN CLOCK. 
 
 Fig. 34. Drawing escape wheel to fit a tracing from a pallet fork. 
 
THE MODERN CLOCK. 121 
 
 closer, mount in the rounding up tool and lap off the cut 
 planes until they are smooth and stand at the proper angle ; 
 then polish. This is done quickly. 
 
 Can we work the rule backwards? Suppose we get a 
 clock in which we have the pallet arbor adjustable as before, 
 and we have the pallet fork all in good shape, but we have 
 lost the escape wheel, or it has been butchered by somebody 
 before coming to us, so that a new one is required. 
 
 Take off the pallet fork; lay it on a sheet of brass and 
 trace around it carefully with a needle point, Fig. 34. 
 Mark the center carefully at the pallet arbor hole and meas- 
 ure carefully the distance between the pallets and mark that 
 center. Draw a center line cutting these centers and ex- 
 tending beyond. Now draw the tangent from the beginning 
 of the entering pallet (as shown by the tracing on our 
 brass), to the pallet center; do the same with the exit pallet. 
 Now take a metal square and place it on one of the tangents 
 exactly, with the end at the beginning of the entering pallet ; 
 trace a line cutting the line of centers and we have the radius 
 of our escape wheel. Trace a circle from the intersection of 
 the radius and the center line and we have the circumference 
 of our escape wheel. This circle should also cut the inter- 
 section of the tangent and radius on the other side if it is 
 drawn correctly; if it does not do this an error has been 
 made in the drawing. 
 
 Having found the diameter and circumference of our 
 escape wheel it may be sawed out and mounted for wheel 
 cutting; or, if we have no wheel cutter and must make 
 the wheel, we must draw it on the brass by hand with a fine 
 needle point before proceeding to saw it out by hand, Fig. 
 35. Say that the wheel is to have thirty-two teeth, which 
 is a common number ; then 360° -^ 32 ^ ii^° as the space 
 between the points of our teeth. Take a large protractor, 
 one with the degrees large enough to be divided (I use a 
 ten-inch) ; place its center on the center of our escape wheel, 
 set off ii^° and mark them on the brass with the needle 
 
122 
 
 THE MODERN CLOCK. 
 
 Fig. 35. Drawing an escape wheel to cut. The last drawing shows the 
 complete wheel. 
 
THE MODERN CLOCK. I23 
 
 point, at the edge of the protractor. Then take a straight 
 edge and draw a radius from the center to the circumfer- 
 ence ; change the straight edge to the other mark and mark 
 the point where it crosses the circumference; set your 
 dividers accurately by this mark and space off the teeth on 
 your circumference. If they are set at eleven degrees and 
 fifteen minutes they will come out exactly at the end. Now 
 take your protractor and with its center at the junction of 
 the radius and circumference set off ten degrees and draw 
 a line past the center of the wheel ; set off twenty degrees 
 and draw another line the same way. From the center of the 
 escape wheel draw two circles just touching these lines. 
 Outside of these draw two circles defining the inner and 
 outer edges of the rim of the wheel. With the straight edge 
 just touching the inner circle draw in the fronts of the teeth ; 
 these will all be set at ten degrees from a radius, so that 
 only the extreme points will touch the locking planes of 
 the pallets and thus reduce the friction during the run. The 
 backs of the teeth are marked out in the same way from 
 the twenty-degree circle. The hub is made to coincide with 
 the ten-degree circle; the spokes are traced in and we are 
 ready to begin sawing out. 
 
 If the workman has a wheel cutter the job is much 
 simpler. A piece of brass is mounted on a cement brass 
 with soft solder, faced off, centered and the pitch circle, 
 inner and outer edges of the rim and the hub are traced with 
 the T-rest and graver. The extra metal is then cut away 
 and a suitable index placed on the spindle and locked. The 
 wheel cutter is set up with a fine toothed, smooth cutting 
 saw on the spindle, horizontal, with its upper edge at the 
 line of centers of the lathe. It is then run out to the cir- 
 cumference of the wheel, turned upwards ten degrees and 
 the wheel cut around. Fig. 36. This makes the fronts of the 
 teeth. Turn the saw ten degrees more and cut the backs 
 of the teeth. Then turn the saw so that it will reach from 
 the front of one tooth to the root of the back of the next 
 
124 "^^^ MODERN CLOCK. 
 
 Fig. 36. Making an escape wheel with a saw, showing the successive 
 
 cuts. 
 
THE MODERN CLOCK. 1 25 
 
 one, without touching either tooth, and cut round again; 
 this cuts out a triangular piece of waste metal between the 
 teeth. Turn the saw again so that it reaches from the bot- 
 tom of the front of a tooth to the top of the back of the next 
 one and cut around again, thus removing another portion 
 of the waste metal, and leaving only a small triangle be- 
 tween the teeth. Lower the saw its own thickness and cut 
 around the wheel again, repeating the operation until the 
 waste metal is all removed and you have a smooth circular 
 rim between the teeth. Fig. 36. 
 
 Set the saw horizontally at the lathe center ; raise it one- 
 half the thickness of the spokes; set the index pin of the 
 lathe head firmly at O ; feed in the saw the thickness of the 
 wheel and make straight cuts across from the circle of the 
 inner rim to the circle marking the hub, but not cutting 
 either ; set the index pin at 30 and repeat ; next lower your 
 saw and cut the other side of the spokes the same way. 
 
 Next you can mount a lap in place of the saw and smooth 
 the fronts and backs of the teeth and if you have a rather 
 thick disc the outer edge of the rim, between the teeth, 
 may also be smoothed. 
 
 If you have a good strong pivot polisher, mount a tri- 
 angular end mill in the spindle, lock the yoke, and cut the 
 arcs of circles of the hub and rim from edge to edge of 
 the spokes, feeding carefully against the mill with the hand 
 on the lathe pulley. 
 
 Put on your jeweling tailstock and open the wheel to fit 
 the pinion, collet, or arbor, if there is no collet. 
 
 You now have the wheel all done, except facing the side 
 that was soldered to the cement brass and trimming up the 
 corners of the spokes at the rim and hub, and 3^ou have got 
 it round, true and correct in much less time than you could 
 have done in any other way, while an immense amount of 
 work with the file and eye-glass has been avoided. It is 
 true because it was soldered in position at the beginning and 
 has not been removed until finished. 
 
126 THK MODERN CLOCK 
 
 Sometimes what are known from their appearance as 
 club-shaped teeth are used in the wheels of Graham's 
 escapements. Pendulums receive their impulse from escape- 
 ments made in this manner partly from the lifting planes on 
 -the pallets, and partly from the planes on the scape- wheel. 
 The advantage gained by this method is, that wheels made 
 in this way will work with the least possible drop, and con- 
 sequently, power is saved; but the power saved is thrown 
 away again in the increased friction of the planes of the 
 wheel against those of the pallets, which is considerably 
 more than when plain-pointed teeth are used on the escape 
 wheel. 
 
 Clock pallets are usually made of steel, and on the finer 
 classes of work jewels are often set into them to prevent the 
 oil from drying, after the same fashion as jewels are placed 
 in steel pallets in a lever watch ; but it is obvious that stone 
 pallets made in this way have to be finished with polishers 
 held in the hand, and that, except in factories, they cannot 
 he made so perfectly regular, especially that pallet that is 
 struck downwards, as the particular action of a fine Graham 
 escapement requires. When great accuracy is required, the 
 pallets are usually made of separate pieces, and the acting 
 circles ground and polished on laps, running in a lathe. 
 This method of constructing pallets also allows a means of 
 adjustment which in some particular instances is very con- 
 venient. 
 
 There is also a plan of making jeweled pallets adjustable, 
 which is practiced on fine work, such as astronomical and 
 master clocks. The pallet fork consists of two pieces of 
 thin, hard, sheet brass, cut out in the usual form and two 
 mounted on one arbor. Circular grooves are cut in the 
 p^des of both plates, at the proper distance, and of the 
 proper size t-o receive the jewels which are the acting parte 
 of the pallets. When jewels cannot be made of the desired 
 size, pallets of steel are made, and the jewels are then set 
 into the steel Ictrge enough for the teeth of the wheel to act 
 
THE MODERN CLOCK, 
 
 127 
 
 o 
 
 Fig. 37. Brocot's visible escapement, escaping over 120* with pointed 
 teeth. Dotted lines on pallets show where they are cut to avoid 
 stopping. 
 
128 THE MODERN CLOCK. 
 
 Upon. The two parts of the fork are fastened at a given 
 distance apart, and the jewels, or pieces of steel, go in be- 
 tween them, and, after they have been adjusted to the proper 
 position, are fastened by screws that pull the frames close 
 together and press against the edges of the jewels. Pallets 
 made in this manner have a very elegant appearance. An- 
 other method is to have only one frame, and to have it thick 
 enough, where the jewels have to be set in, to allow a groove 
 to be cut in its side as deep as the jewels (or the pieces of 
 steel that hold the jewels) are broad, and which are held in 
 their proper position by screws. This system of jeweling 
 pallets is frequently adopted by the makers of fine mantel 
 clocks. 
 
 Brocoi's Visible Escapement. — Fig. ^y represents a 
 system of making and jeweling pallets much used by the 
 French in their small work, especially in visible escapements. 
 The acting parts of the pallets are simply cylinders, gener- 
 ally of colored stones, usually garnets, one-half of each 
 cylinder being cut away. These cylinders extend some dis- 
 tance from the front of the pallet frame, and work into the 
 escape wheel the same as the pallets of a Graham escape- 
 ment — the round parts of the pallets serving as impulse 
 planes. The neck of the brass pallet frame is cut up in the 
 center, and the width between the pallets is sometimes ad- 
 justed by a screw, sometimes by bending the arms. 
 
 Clock movements with this escapement, of a careful con- 
 struction, will frequently come for repairs, accompanied by 
 the complaint of constant stopping and that no attempt at 
 closely regulating can succeed with them, although they 
 appear to have no visible disturbing cause. In such cases 
 the depthing of the escapement is generally wrong. With 
 proper depthing the point of the escape wheel tooth should 
 drop on the center or a little beyond the center of the pallet 
 stone. If it is set in this way the clock will stop when 
 wound, especially if it has a strong spring, as the light 
 
THE MODERN CLOCK. 
 
 129 
 
 Fig. 38. Brocot's visible escapement escaping over 90° with a small lift 
 on the escape wheel teeth. 
 
130 THE MODERN CLOCK. 
 
 pendulum will not then have momentum enough to unlock 
 it against the full power of the spring. If the pallets are set 
 shallow, in order to avoid this difficulty, then, the pendulum 
 will take too short a swing and thus the clock will have a 
 gaining rate. Generally the pendulum ball cannot be made 
 enough heavier to correct the defect. 
 
 In these movements, in which the length of the pendulum 
 does not exceed 4 inches, the pallet fork embraces, generally 
 about 120°, or the one-third part of the wheel; it will be 
 seen that unless there are stop works on the barrel of the 
 main spring no manner of regulating is possible with these 
 conditions, in view of the considerable influence exercised 
 by the mainspring through the train on the very light pendu- 
 lum, and by replacing this unduly high anchor by a lower 
 one, I have always been able to produce a very satisfactory 
 rate with movements having pendulums of three and a half 
 to four inches. Fig. 38 shows a 90° escapement with a 
 small lift on the escape wheel teeth. 
 
 In spite of its incontestable qualities, the visible escape- 
 ment possesses one inherent fault. I refer to the formation 
 of its pallets, the semi-circular shape of which renders 
 unequal the action of the train in giving impulse to the 
 pendulum exceeding 50 centimeters (20 inches), since to 
 make it to describe arcs of from one to two degrees only, 
 with pendulums of from 60 centimeters to one meter in 
 length, it became necessary to make the anchor arms ex- 
 tremely long, which considerably impeded the freedom of 
 action, especially when the oil became thick, and this dis- 
 position would, therefore, stand in direct contradiction with 
 the principles of modern horology. Both stopping and 
 the irregularity of rate can be obviated by changing the 
 semi-circular form of the pallets for one of an inclinea 
 plane, either by grinding a new plane or turning the stones 
 in such manner as to offer an inclined plane to the action 
 of the wheel, analagous to that of the Graham escapement. 
 
THE MODERN CLOCK. I3I 
 
 See Fig. 37, the dotted lines on the pallets showing the 
 portion to be ground away. 
 
 The importance of this transformation will readily be 
 understood ; it suffices to give to these planes a more or less 
 large inclination in order to obtain a greater regularity of 
 lifting, and, at desire, a lifting arc more or less considerable 
 without being compelled to modify the proportions of the 
 fork or to exaggerate the center distance of wheel and 
 pallet arbor. 
 
 In adjusting an escapement, perhaps it may be advisable 
 to mention that moving the pallets closer together, or open- 
 ing them wider, will only adjust the drop on one side, while 
 the other drop can only be affected by altering the distance 
 between the centers of the pallets and scape-wheel. This is 
 accomplished in various ways. The French method con- 
 sists of an eccentric bush, riveted in the frame just tight 
 enough to be turned by a screw-driver. Another plan, com- 
 mon in America, is simply pieces of brass (cocks) fastened 
 on the sides of the frames. The pivots of the pallet axis are 
 hung. in holes in these cocks, and an adjustment of great 
 accuracy may be quickly obtained by loosening the clamping 
 screws. Lock, drop and run should be of the same amount 
 on each pallet. However, we do not approve of adjustments 
 of any kind, except in the very highest class of clocks, 
 where they ai^ always likely to be under the care of skillful 
 people, who understand how to use the adjustments to obtain 
 nicety of action in the various parts. 
 
 In making escapements, lightness of all the parts ought 
 to be an object always in view in the mind of the workman, 
 and such materials should be used as will best serve that 
 purpose. The scape-wheel, and the pallets and fork, should 
 have no more metal in them than is necessary for stiffness. 
 The pallet arbor, and also the escape-wheel arbor, should 
 be left pretty thick when the wheel and pallets are placed 
 in the center between the plates, to prevent their springing 
 when giving impulse to the pendulum. We have often been 
 
132 THE MODERN CLOCK. 
 
 puzzled to find out the necessity or the utihty of placing 
 them in the center between the plates, as they are so gener- 
 ally done in English clockwork. The escapement acts much 
 more firmly when it is placed near one of the plates, and it 
 is just as easy to make it in this way as in the other. 
 
 It is often assumed that the friction of the teeth on the 
 circular part of the pallets of a dead-beat escapement is 
 small in amount and unimportant in its value. With re- 
 spect to its amount, we believe it is often not far short of 
 being equal to one-half of the combined retarding forces 
 presented to the pendulum; and with respect to its being 
 unimportant, this assumption is founded on the supposition 
 that it is always a uniform force, when it is easy to show 
 that it is not a uniform force. It is very well known that the 
 force transmitted in clock trains, from each wheel to the 
 next, is very far from being constant. Small defects in the 
 forms of the teeth of the wheels and of the leaves of the 
 pinions, and also in the depths to which they are set into 
 each other, cause irregularities in the amount of power 
 transmitted from each wheel to the next ; and the accidental 
 combination of these irregularities in a train of four or five 
 wheels, makes the force transmitted from the first to the last 
 exceedingly variable. The wearing of the parts and the 
 change in the state of the oil, are causes of further irregu- 
 larities ; and, from these causes, it must be admitted that the 
 propelling power of the scape-wheel on the pallets is of a 
 variable amount, and a more important question for consid- 
 eration than it is usually supposed to be. To avoid the con- 
 sequences of this irregular pressure of the scape-wheel on 
 the pallets being communicated to the pendulum, is a prob- 
 lem that has puzzled skillful mechanicians for many years ; 
 for, although we find the Graham escapement to be pro- 
 nounced both theoretically and mechanically correct, and 
 by some authorities little short of perfection, we find some of 
 these same authorities — both theoretically and practically — 
 testify their dissatisfaction with it by endeavoring to im- 
 
THE MODERN CLOCK. 
 
 33 
 
 prove on it. In Europe the experience of generations and 
 the expenditure of small fortunes, in pursuit of this im- 
 provement, through the agency of the gravity, and other 
 ::orms of escapements, proves this fact ; while of late years, 
 in the United States, much time and money has been spent 
 on the same subject, and results have been reached which 
 have raised questions that ten years ago were little dreamed 
 of by those clockmakers who are generally engaged on the 
 highest class of work. 
 
 While considering this class of escapements, we would 
 say a few words in regard to the sizes of escape wheels 
 generally used. Small wheels can now be cut as accurately 
 as larger ones and there is now no reason or necessity for 
 continuing the use of a wheel of the size Graham and 
 Le Paute used, and which has been the size generally 
 adopted by most European makers who use these escape- 
 ments. The Germans and Swiss make wheels much smaller 
 for Graham escapements than the English makers do ; and 
 the American factories make them smaller still. On the 
 continent of Europe the wheels of Le Paute's escapement 
 are made much larger than they are made in England and 
 in the United States. No wheel, and more especially a 
 scape-wheel, should be larger than will just give sufficient 
 strength for the number of teeth it has to contain, in pro- 
 portion to the amount of work that it has to perform. The 
 amount of work a scape-wheel has to perform in giving mo- 
 tion to the pendulum is of the lightest description, and not 
 more than one-tenth of what it is popularly supposed to 
 be, which is shown by its variation under slight increase of 
 friction ; therefore we do not consider that we take extreme 
 ground in recommending wheels for these escapements to be 
 made nearly half the size their originators made them, and 
 the pallets drawn off in proportion to the reduced size of 
 the wheel. It is plain that by reducing the size of the wheel 
 its inertia will be reduced. When the teeth begin to act 
 on the inclined planes of the pallets, the wheel will be set in 
 
134 
 
 THE MODERN CLOCK. 
 
 motion with greater ease, as it has a shorter leverage, and 
 the amount of the dead friction of the scape-wheel teeth on 
 the inclined planes and circular part of the pallets will also 
 be proportionately reduced by making the wheel smaller. 
 Factory experience and examination of a large number of 
 clocks in repair shops have also shown that smaller and 
 thicker escape .wheels will wear much longer than larger 
 and thinner ones, as all the wear is at the points of the 
 teeth and this is the portion to be protected. 
 
CHAPTER IX. 
 
 LE PAUTE's pin wheel ESCAPEMENT. 
 
 Probably in no other escapement, except the lever, has 
 there been so many modifications as in the pin wheel ; this 
 is so to such an extent that it will be found by the student 
 that nearly every escapement of this kind which he will 
 examine will differ from its fellows if it has been made by 
 a different maker. They will be found to vary in the lengths 
 of the pallet arms from three-fourths to one and a half times 
 the diameter of the escape wheel; some of them will have 
 the longer arm of the pallets outside and some inside; some 
 will have the lift for both pallets laid out on one side of the 
 perpendicular P, Fig. 39, while others will have the lift 
 divided, with the perpendicular in the center. Very old 
 escapements have the pallet center directly over the escape 
 wheel center, while the pallet arms work at an angle of 45°, 
 while others have them with the pallet center planted on a 
 perpendicular, tangent to the pitch line of the escape wheel. 
 Some have the circular rest or locking faces of the pallets 
 rounded slightly to hold the oil in position while others have 
 them flat and still others have them made of hard stone, pol- 
 ished. More than half have the pins in the escape wheel cut 
 away for one-half of their diameters, leaving the bottoms 
 Vound, as shown in Fig. 39, while others use a wider pin and 
 trim away the bottoms also, as in Fig. 40, leaving the lifting 
 surface on the pins not more than one-fourth the arc of the 
 circle. This is especially true of the larger escapements 
 used in tower clocks, though they are also found in regu- 
 lators. 
 
 In view of the wide variation in practice, therefore, we 
 have endeavored to present in Fig. 39 a conservative state- 
 
 135 
 
36 
 
 TJIE MODERN CI.OCK. 
 
 ment of the general practice as found in existing clocks. We 
 say existing, because very few of these escapements are 
 made now — none at all in America — and those in use are 
 
 Fig. 39. Pin Wheel Escapement. 
 
 generally in imported regulators, which have come from 
 Switzerland or Germany. The Waterbury Clock Co. at 
 one time made this escapement for its regulators and the 
 
THE MODERN CLOCK. 
 
 137 
 
 Seth Thomas Clock Company made a number of its early 
 tower clocks with it, but both have discontinued it for some 
 years, and it is safe to say that any movement coming into 
 
 Fig. 40. Pin Wheel With Flattened Teeth. 
 
 the watchmaker's hands which has this escapement is im- 
 ported; or if American, it is out of the market. 
 
 Le Paute claimed as an advantage the fact that the im- 
 pact of the escape wheel teeth is downward on both pallets, 
 whereas in the gravity and recoil escapements one blow is 
 struck upwards and the other downwards. He claimed that 
 
138 THE MODERN CLOCK. 
 
 by this means a better action was secured after the pivot 
 holes began to wear, as there was less lost motion with both 
 blows in the same direction and any shake would not affect 
 the amount of impulse given to the pendulum. The differ- 
 ence is more theoretical than practical, however, and the 
 escapement possesses one serious fault, which is that the 
 pins forming! the escape wheel teeth conduct the oil away 
 from thC; palliets, so that the clock changes its rate in from 
 eight months H;o one year after being oiled and cleaned. The 
 most effective means of counteracting this is to round the 
 locking planes of the pallets slightly, so that the oil will be 
 held on them by capillary attraction. Another method is 
 to turn the pins so that they are thicker in diameter at the 
 point of contact with the pallets, but this is seldom tried. 
 The best plan is to keep the pallets as close as they can be 
 to the face of the wheel without touching. 
 
 To Draw the Escapement. — In laying out this escape- 
 ment the first thing to consider is the arc of swing of the 
 pendulum, because one-half of the lift is on the pin and 
 consequently one-half the lift must equal one-half the diam- 
 eter of the pin, as shown in Fig. 39. If the pendulum swings 
 four degrees, then the diameter of each pin must equal four 
 degrees of the pallet movement. This establishes the size of 
 our pin ; it is measured from the pallet staff hole. There are 
 30 of these pins for a second's pendulum, and unless it is a 
 very large escapement the pins cannot be made less in di- 
 ameter than one-fourth the distance between the pins, or 
 they will be too weak and will spring; consequently 
 360-4-30=12° and i2°-^4=3°, so that three degrees of 
 the pitch line of the escape wheel equals the swing of the 
 pallet fork. This establishes the relation as to size between 
 the escape wheel and the opening, or swing of the pallet 
 fork. Draw a perpendicular, P, from the pallet center and 
 on one side of it lay out the lift lines L, L; draw a line at 
 right angles to the perpendicular and where it crosses the 
 
THE MODERN CLOCK. 
 
 39 
 
 inner lift line draw a circle touching the outer lift line. The 
 diameter of this circle equals three degrees of the circum- 
 ference of the wheel, on its pitch line, and .this multiplied by 
 120 gives 360° or the pitch circumference of the escape 
 wheel. Dividing the sum so found by 3. 141 5 gives the di- 
 ameter of the escape wheel and half of this is the radius. 
 After finding the radius draw the pitch circle and set out 
 the other twenty-nine teeth spaced twelve degrees apart, and 
 drawn in half circles as shown in Fig. 39. 
 
 Now to get the thickness of the pallet arms. When the 
 pin shown in action in Fig. 39 has just cleared the lower 
 edge of the inner pallet, the succeeding pin should fall safely 
 on the upper corner of the outer pallet; consequently the 
 thickness of these two arms, the pin between them, and the 
 drop (clearance between the pin and the lower edge of the 
 upper pallet) should just equal the distance between two 
 pins, from center to center, or 12° of the escape wheel. 
 With the first or inner lift line as a starting point, draw the 
 lower arcs of the pallets and draw the upper or locking 
 planes from the perpendicular and the outer lift line. Then 
 draw the lifting planes of the pallets by connecting the ends 
 of these arcs. The enlarged view above the escape wheel 
 in Fig. 39 will show how this is done more clearly than the 
 main drawing. 
 
 It is best to make the pallet fork of steel, in two pieces, 
 screwed to a collet on the pallet arbor, as the inner arm must 
 be bent, or offset, so that it will clear the pins of the escape 
 wheel, and the pallets should lie in the same plane, as close 
 to the wheel as is possible without touching it. The pallets 
 are hardened. 
 
 In tower clocks the escapement is so large that a pin 
 having a diameter of three degrees of the escape wheel gives 
 a half pin of greater strength than is necessary for the 
 work to be done and such pins are cut away on the bottom, 
 as in Fig. 40. In making the wheel it should be drilled in 
 the lathe with the proper index to divide the wheel and the 
 
140 THE MODERN CLOCK. 
 
 pins riveted in; then the pins are cut with a wheel cutter 
 as if they were teeth of a wheel. Pins should be of hard 
 brass. 
 
 Care should be used in handling clocks with this escape- 
 ment while the pendulum is connected with the pallet fork, 
 as, if the motion of the fork should be reversed while a pin 
 was on one of the lifting planes, it would bend or break the 
 pin. 
 
CHAPTER X. 
 
 THE RECOIL OR ANCHOR ESCAPEMENT. 
 
 This escapement, always a favorite with clockmakers, 
 has had a long and interesting history and development. 
 Because it started with a suddenly achieved reputation, and 
 because it is adapted to obtain fair results with the cheapest 
 and consequently most unfavorable working conditions, it 
 has won its way into almost universal use in the cheaper 
 classes of clock work; that is to say, it is used in about 
 ninety per cent of the pendulum clocks which are manu- 
 factured to-day. 
 
 It achieved a sudden reputation at its birth, because it 
 was designed to replace the old verge, which, with its ninety 
 degree pallets close to the arbor, and working into the 
 crown wheel, required a very large swing of the pendulum. 
 This necessitated a light ball, a short rod, required a great 
 force to drive it, and made it impossible to do away with 
 the circular error, while leaving the clock sensitive to vari- 
 ations in power. The recoil escapement was therefore the 
 first considerable advance in accuracy, as its use involved 
 a longer and heavier pendulum, shorter arcs of vibration 
 and less motive power than was practicable with the verge ; 
 and as the pendulum was less controlled by the escapement, 
 it was less influenced by variations of power. 
 
 In the early escapements the entrance pallet was convex 
 and the exit pallet concave. Escapements of this description 
 may still be met with among the antiquities that occasionally 
 drift into the repair shop. Later on both pallets were made 
 straight, as shown in Fig. 41. It will be seen by studying 
 the direction of the forces that the effect is to wear off the 
 
 141 
 
142 
 
 THE MODERN CLOCK. 
 
 points of the teeth very rapidly, and for this reason the 
 pallets were both made convex (See Fig. 42), so as to bring 
 the rubbing action of the recoil more on the sides of the 
 
 Fig. 41. Recoil Escapement with Straight Lifting Planes. 
 
 teeth and do away to a large extent with the butting on the 
 points which destroyed them so rapidly. 
 
 The rather empirical methods of laying out the recoil 
 escapement, which have gained general circulation in works 
 on horology, have had much to do with bad depthings of 
 
THE MODERN CLOCK. I43 
 
 .this escapement and the consequent undue wear of the 
 escape wheel teeth and great variation in time keeping of 
 the movements in which such faulty depthings occur, par- 
 ticularly in eight-day movements with short and light pen- 
 dulums. The escapement will invariably drive the clock 
 faster for an increase of power and slower for a decrease ; 
 an unduly great depthing will greatly increase the arc of 
 vibration of the pendulum, as the train exerts pressure on 
 the pendulum for a longer period during the vibration ; the 
 consequence is that instead of the pendulum being as highly 
 detached as possible, we have the opposite state of affairs 
 and a combination of a strong spring, light pendulum and 
 excessive depthing will easily make a variation of five min- 
 utes a week in an eight-day clock. 
 
 The generally accepted method of laying out this escape- 
 ment is shown in Figs. 41 and 42, as follows : "Draw a 
 circle representing the escape wheel ; multiply the radius of 
 the escape wheel by 1.4 and set off this as the center dis- 
 tance between the pallet and escape wheel centers. From 
 the pallet staff center describe a circle with a radius equal to 
 half the distance between escape wheel and pallet centers. 
 Set off on each side of the center line one-half the number of 
 teeth to be embraced by the pallets and from the points of 
 the outside teeth draw lines tangent to the circle described 
 from the pallet center. These lines would then form the 
 faces of the pallets if they w^ere left flat." 
 
 We wonder how much information this description and 
 the drawing conveys to the average reader. How long 
 should the pallets be? What is the drop? How much will 
 the escape wheel recoil w^ith such a depthing? What arc 
 will the pallets give the pendulum ? Why should the center 
 distance always be the same (seven tenths of the diameter 
 of the wheel) whether the escapement embraces eight, or ten, 
 or six teeth ? As a matter of fact it should not be the same. 
 We could ask a few more questions as to other details of 
 this formula, but it will be seen that such a description is 
 
144 
 
 THE MODERN CLOCK. 
 
 practically useless to all but those who are already so skilled 
 that they do not need it. 
 
 Fig. 42. Recoil Escapement with Curved Lifting Planes. 
 
 Let us analyze these drawings. A little study of Figs. 
 41, 42 and 43 will show that there is really only one point of 
 difference between them and Fig. 32, which shows the ele- 
 
THE MODERN CLOCK. 
 
 H5 
 
 ments of the Graham, or dead beat. The sole difference is 
 in the fact that there are no separate locking planes in the 
 recoil, the locking and run taking place on an extension of 
 the lifting planes. Otherwise we have the same elements 
 in our problem and it may therefore be laid out and handled 
 
 V -L 
 
 Fig. 43. Drawing the Lock Lift and Recoil of the Usual Form. 
 
 in the same manner; indeed, if we were to set off on Fig. 
 32, the amount of angular motion of the pallet fork which 
 is taken up by the run of the escape wheel teeth on the 
 locking planes, by drawing dotted lines above the tangents, 
 T, we should then have measured all the angles necessary to 
 intelligently set out the recoil escapement. We should have 
 the lock at the tangent, T, the lift and the run (or recoil) 
 
146 
 
 THE MODERN CLUCK. 
 
 being defined by the lines on either side of it, and the length 
 of our running and lifting planes would be found for the 
 entering pallet by drawing a straight line between the points 
 of the two acting teeth of the escape wheel and noting 
 where this line cut the lines of recoil and lift. A similar 
 line traced at right angles to this would in the same way 
 
 Fig. 43. Show in 
 
 lie Usual- Position in Cheap Clocks and the Verge 
 Wire. 
 
 define the limits of run and lift on the exit pallet. It will 
 therefore be seen that our center distances for any desired 
 angle of escapement may be found in the same way (Fig. 
 28), for either escapement, and thus the method of making 
 the pallets for the ordinary American clock, Fig. 43, be- 
 comes readily intelligible. The sole object of curving the 
 pallets, as explained previously, was to decrease the butting 
 effect of the run on the points of the teeth. This is ac- 
 
THE MODERN CLOCK. 
 
 147 
 
 complished in Fig. 43 by straight planes on the pallets and 
 straight sides to the teeth with 20° teeth on the escape 
 wheel; merely inclining the plane of the entering pallet 
 about six degrees toward the escape wheel center, thus serv- 
 
 Fig. 44. Recoil with Curved Planes. 
 
 ing all purposes, 'while the gain in the cost of manufacture 
 by using straight instead of curved pallets and wheel teeth 
 is very great. 
 
 One factory in the United States is turning out 2,000,000 
 annually of two movements, or about 1,000,000 of each 
 movement; there are four other larger factories and several 
 
148 TJIE MODERN CLOCK. 
 
 with a less product; so it will readily be seen that any de- 
 crease in cost, however small it may be on a single move- 
 ment, will run up enormously on a year's output. Suppose 
 the factory mentioned were enabled to save only one-eighth 
 r>f a cent on one of its million movements manufactured last 
 year, this would amount to $1,250 per year, a little over 
 $100 per month. Thus it will be seen that close figuring on 
 costs of production is a necessity. 
 
 
 Fig. 46. Drum Escapement. 
 
 Fig. 44 shows the method of drawing the escapement 
 according to the common sense deductions given above. As 
 the methods of laying out the angle of escapement, lock, lift, 
 and run, were given in detail in Figs. 28 to 32, they need not 
 be repeated here. 
 
 Fig. 46 shows the escapement frequently used in French 
 "drum'' clocks and hence called the "Drum"' escapement. 
 These are clocks fitted to go in any hole of the diameter of 
 the dial and hence they have very short, light pendulums. 
 An attempt is made to gain control over the pendulum by 
 
THE MODERN CLOCK. I49 
 
 decreasing the arc of escapement to not more than two and 
 sometimes to only one tooth. This gives an impulse to the 
 pendulum only on one-half of the vibrations, the escape 
 wheel teeth resting and running on the long circular locking 
 pallet during alternate swings of the pendulum. The idea 
 is that the friction of the long lock will tend to reduce the' 
 effect of the extra force of the mainspring when the clock 
 is freshly wound. Such clocks often stop when the clock 
 is nearly run down, from deficiency of power, and stop 
 when wound, because the friction of the escape wheel teeth 
 on the locking plane is such as to destroy the momentum 
 of the light pendulum. All that can be done in such cases 
 is to alter the locking planes as shown by the dotted lines, 
 so that the "drum" becomes virtually a recoil escapement 
 of two teeth. ' 
 
CHAPTER XI. 
 
 THE DENNISON OR GRAVITY ESCAPEMENT. 
 
 The distinguishing feature of this escapement lies in the 
 fact that it aims to drive the pendrlum by appl}dng to it a 
 falling weight at each excursion on each side. As the weight 
 is lifted by the train and applied to the pendulum on its re- 
 turn stroke and there is no other connection, it follows that 
 the pendulum is more highly detached than in any other 
 form of pendulum escapement. This should make it a bet- 
 ter time-keeper, as the application of the weight should give 
 a constant impulse and hence errors and variations in the 
 power which drives the train may be neglected. 
 
 On tower clocks this is undoubtedly true, as these clocks 
 are interfered with by every wind that blows against the 
 hands, so that a detached pendulum enables a surplus of 
 power to be applied to the train to meet all emergencies. 
 With a watchmaker's regulator, however, the case is dif- 
 ferent. Here every effort is made to favor the clock, vibra- 
 tions, variations of temperature, variations of power, dirt, 
 dust, wind pressure and irregularities of the mechanism are 
 all carefully excluded and the consequence is that the spe- 
 cial advantages of the gravity escapement are not apparent, 
 for the reason that there are practically no variations for 
 the escapement to take care of. Added to this we must con- 
 sider that the double three-legged form, which is the usual 
 one, is practically an escape wheel of but six teeth, so that 
 another wfleel and pinion must be added to the train and this, 
 with the added complications of the fan and the heavier driv- 
 ing weight required, counterbalance its advantages and bring 
 it back to an equality of performance with the simpler mech- 
 anism of the well made and properly adjusted dead beat es- 
 
 150 
 
THE MODERN CLOCK. I^I 
 
 capement. Theoretically it should work far better than the 
 dead beat, as it is more detached ; but theory is always modi- 
 fied by working conditions and if the variations are lacking 
 there is no special advantage in constructing a mechanism 
 to take care of them. This is the reason why so many 
 watchmakers have constructed for themselves a regulator 
 with this escapement, used in the making all the care and 
 skill of which they were capable and then been disappointed 
 to find that it gave no better results with the same pendulum 
 than the dead beat it was to replace. They had eliminated 
 all the conditions under which the detached escapement 
 would have shown superiority. 
 
 Although the gravity escapement will not give a superior 
 performance under the most favorable conditions for time- 
 keeping, it is distinctly superior when these conditions are 
 unfavorable and therefore fully merits its high place in the 
 estimation of the horological fraternity. We have instanced 
 its value in tower clock work; it has another advantage in 
 running cheap and poorly made (home made) regulators 
 with rough and poor trains ; therefore, it is a favorite escape- 
 ment with watchmakers who build their ow^n regulators 
 while they are still working at the bench, before entering 
 into business for themselves. As the price. of a first-class 
 clock for this purpose is about $300 and the cheapest that is 
 at all reliable is about $75, it will be seen that the tempta- 
 tion to build a clock is very strong and many of them are 
 built annually. 
 
 Regulators with the gravity escapement are built by the 
 Seth Thomas Clock Co., the Howard, and one or two others 
 in this country, but they are furnished simply to supply the 
 demand and sales are never pushed for the reasons given 
 previously. Clocks with this escapement are quite common 
 in England and many of them have found their way to 
 America. It is one of the anomalies of trade that our clock- 
 makers are supplying Europe with cheap clocks, while we 
 are importing practically all the high-priced clocks sold in 
 
153 
 
 THE MODERN CLOCK. 
 
 Fig. 47. 
 
THE MODERN CLOCK. I53 
 
 the United States and among them are a few having the 
 three-legged and four-legged gravity escapements, therefore 
 the chances are that when a repairer finds such a clock it is 
 likely to be either of English origin or homemade, unless it 
 be a German regulator. 
 
 Figs. 47 and 48 show plans and side views of the three- 
 legged escapement. Fig. 48 also shows an enlarged view of 
 the escape wheel, showing how the three-leaved pinion be- 
 tween the tw^o escape wheels, is made where it is worked 
 out of the solid. A, B and C and a, b and c show the escape 
 wheel which is made up of two three-armed wheels, one on 
 each side of a three-leaved pinion marked D^ and D^ in the 
 enlarged view of Fig. 48. The pallets in this escapement 
 consist of the two arms of metal suspended from points op- 
 posite the point of bending of the pendulum spring and the 
 lifting planes are found on the ends of the center arms in 
 these pallets, which press against the three leaves of the 
 pinion, while the impulse pins e^ and e-. Fig. 47 and 48 act 
 directly upon the pendulum in place of the verge wire. The 
 pallets act between the wheels in the same plane as each 
 other. The lifting pins or pinion leaves act on the lifting 
 planes after the line of centers when the long teeth or legs 
 of the escape wheels have been released from the stops, F 
 and G, Figs. 47 and 48, which are placed one on each side 
 of the pallets and act alternately on the wheels. These pal- 
 lets are pivoted one on each side of the bending point of the 
 suspension spring. To lay out the escapement, draw a cir- 
 cle representing the escape wheel diameter, then draw the 
 line of centers and set off on the diameter of the escape 
 wheel from each side of the line of centers 60° of its cir- 
 cumference, thus marking the positions for the pallet stops 
 120° apart. Draw radii from the center of the escape wheel 
 to these positions and draw tangents from the ends of these 
 radii toward the center line. The point where these meet 
 will be the bending point of the pendulum spring. 
 
154 
 
 THE MODERN CLOCK. 
 
 Fig. 48. 
 
THE MODERN CLOCK. I55 
 
 This is clearly shown at H, Fig. 47. The points of sus- 
 pension for the pallets are planted on the line of these tan- 
 gents and a little be!ow the point H, where the tangents meet 
 on the line of centers. This is done to avoid the mechanical 
 difficulty of having the studs for the two pallets occupy the 
 same place at the same time. The arms of the pallets below 
 the stops may be of any length, but they are generally con- 
 structed of the same angle as the upper arms and will be 
 all right if drawn parallel to these upper arms. They are in 
 some instances continued further down, but this is largely 
 a matter of taste and the lower portion of the escapement is 
 generally drawn so as to be symmetrical. 
 
 The impulse of the pendulum is given by having pins prO" 
 jecting from the pallet arms and bearing upon the pendulum 
 rod, which pins may be of brass, steel or ivory. In the 
 heavier escapements they are made of ivory in order to avoid 
 any chatter from contact with the pendulum rod of a heavy 
 pendulum. These pallets should be as light as it is possible 
 to make them without having them chatter under the im- 
 pact of the escape wheel arms on the stops. They have only 
 to counteract the force of the pendulum spring and the re- 
 sistance of the air and for light pendulums this force is much 
 less than is generally understood. Two ounces of impulse 
 will maintain a 250-pound pendulum, but two pennyweights 
 is more than sufficient for a fifty-pound pendulum. The 
 reader can see that in the case of a pendulum weighing but 
 eight to fourteen pounds, there w^ill be a still greater pro- 
 portionate drop, as the spring itself is thinner, the rod is 
 thinner, the pendulum ball oi¥ers little resistance to the air 
 and the consequence is that it is difficult to get the pallet 
 arms light enough for an ordinary clock. 
 
 Watchmakers who make this escapement for themselves, 
 to drive an eight to fourteen pound pendulum., generally 
 make the escape wheel three inches diameter and make the 
 escape wheel and pallet arms all from the steel obtained by 
 buying an ordinary carpenter's saw. The lifting planes 
 
1^6 THE MODERN CLOCK. 
 
 should not be more than one-eighth its diameter from the 
 center of the escape wheel, as where this is the case the 
 circular motion of the center pins will be so great that the 
 pallet in action will be thrown out too rapidly and will chat- 
 ter when striking the pendulum rod. On the other hand it 
 should not be less than one-twelfth of the diameter of the 
 escape wheel, or the pendulum will not be given sufficiently 
 free swing and the motion will be so slow that while such a 
 clock will work under favorable conditions, jarring, shak- 
 ing in wind storms, etc., will have a tendency to make the 
 pendulum wabble and stop the clock. From what has been 
 said above, it will also be seen that the necessity for slow 
 motion of the pallet arms unfits this escapement for use with 
 short pendulums. 
 
 The action of the escapement is as follows : The pendu- 
 lum traveling to the right, when it has thrown the right 
 pallet arm sufficiently far, will liberate the escape wheel 
 tooth from the stop G and the pinion, acting on the lifting 
 plane, will raise the pallet arm, allowing the pendulum to 
 continue its course without doing any further work until 
 it has reached nearly its extreme point of excursion, when 
 the weight of the pallet will be dropped upon the pendulum 
 rod and remain there, acting upon the pendulum until it has 
 passed the center when the pallet arm will be stopped by the 
 banking pin M^ ; exactly the same procedure takes place on 
 the left side of the escapement during the swing of the pen- 
 dulum to the left. The beat pins M and M^ should be set 
 so that the impulse pins e^ and e^ will just touch the pen- 
 dulum when the latter is hanging at rest and the escapement 
 will then be in beat. The stops should be cut from sheet 
 steel and the locking faces of the escape wheel arms, stops 
 on the pallets, lifting planes of the pallets and the lifting pins 
 should all be hardened. In some of the very fine escape- 
 ments the faces of the blocks are jeweled. The arnis of the 
 inner part of the escape wheel are usually set at equal an- 
 gular distances between those of the outer, although this is 
 
THE MODERN CLOCK. 
 
 157 
 
 not absolutely necessary, and the lifting pins are set on radii 
 to the acting faces of the arms of one of the wheels, so as to 
 cross the line of centers at the distance from the center, not 
 exceeding one-eighth of the radius of the wheel, for the 
 reasons explained above. 
 
 Fig. 49. 
 
 From the comparatively great angle at which the arms are 
 placed, the distance through which they have to be lifted to 
 give sufficient impulse is less in this escapement than in one 
 with a larger number of teeth acting in the same plane, as 
 the pallets would then hang more nearly upright. This is a 
 great advantage, as the contact is shorter. The unlocking is 
 also easier for the same reason, and from the greater diame- 
 ter of the wheel in proportion to other parts of the escape- 
 
138 THE MODERN CLOCK. 
 
 ment, the pressure on the stops is considerably less. The two 
 wheels must be squared on the arbor, so there will be no 
 possibility of slipping. The lifting pins D are shouldered 
 between them like a three-tooth lantern pinion. In small 
 escapements the lifting pins are not worked out of the solid 
 arbor, but are made as hardened screws to connect the two 
 portions of the wheel. In tower clocks the pinion is gener- 
 ally made solid on the shaft J, Fig. 48. The wheel, A, B, C, 
 is made to pass over the pinion D and is fitted to a trian- 
 gular seat, the size of the triangle of the leaves, D, against 
 the collar on the shaft. The other wheel, a, b, c, is fitted 
 to the inside triangle of the pinion, so that the leaves, D, 
 form a shoulder against which it fits. The pallets, E and E^, 
 also lie in one plane between the wheels, but one stop, F, 
 points forward to receive the A, B, C, teeth and the other, 
 G, points backward to receive the a, b, c teeth alternately. 
 The distance of the pendulum top, H, or cheeks from the 
 center of the escape wheel, J equals the diameter of the 
 escape wheel. The lifting pins should be so placed that the 
 one which is holding up a pallet and the one which is to lift 
 next will be vertical over each other, on the line of centers, 
 the third pin being on the level with the center, and to one 
 side of it, see Fig. 48, enlarged view. 
 
 The fly is a very essential part of this escapement, as the 
 angular motion of the escape wheel is such that unless it 
 were checked it would be apt to rebound and unlock; con- 
 sequently, a large fly is always a feature of this escapement 
 and is mounted upon the scape wheel arbor with spring fric- 
 tion in such a way that the fly can continue motion after the 
 scape wheel has been stopped. This is provided for by a 
 spring pressure, either like the ordinary spring attachment 
 of the fly of striking trains of small clocks, or as shown in 
 Fig. 49 for tower clocks. This fly is effective in propor- 
 tion to its length and hence a long narrow fly will be better 
 than a shorter and wider one, as the resistance of the air 
 
THE MODERN CLOCK. 
 
 159 
 
 Fig, 50. 
 
l6o THE MODERN CLOCK. 
 
 striking against the ends of the fly is much greater the fur- 
 ther you get from the center. 
 
 The pallet stud pins and the impulse pins should on no 
 account be touched with oil or other grease of any kind, 
 -but be left dry whatever they are made of, because the slight- 
 est adhesion betw^een the impulse pins and the pendulum rod 
 is fatal to the whole action of the escapement. Care must 
 also be taken that one pallet begins to lift simultaneously 
 with the resting of the other, neither before nor after. 
 
 The gravity escapement requires a heavier weight or 
 force to operate the train than a dead beat escapement, be- 
 cause it must be strong enough to be sure of lifting the pal- 
 lets quickly and firmly, and also because the escape wheel 
 having but six teeth necessitates the use of another wheel 
 and pinion between the escape and center and consequently 
 the train is geared back more than it would be for a dead 
 beat escapement, with the seconds hand mounted on the es- 
 cape wheel arbor. But with this form of escapement the 
 superfluous force does not work the pendulum and it does 
 no harm if the train is good enough not to waste power in 
 getting over rough places left in cutting the teeth of the 
 wheels or any jamming from those which have unequal 
 widths or spaces. For this reason a high numbered train is 
 better than a low numbered one, as these defects are greater 
 on the teeth of a low numbered train and any defect in such 
 cases will show itself. 
 
 In the gravity escapement the escape wheel must have a 
 little run at the pallets before it begins to lift them and in 
 order to do this the banking pins, M, M^, for the pallet arms 
 to rest on, should hold them just clear of the lifting pins 
 or leaves of the escape wheel. The escape wheel should be 
 as light as possible, for every blow heard in the machine 
 means a loss of power and wear of parts. Of course, in an 
 escapement a sudden stop is expected, but the light wheel 
 will reduce it to a minimum if the fan is large enough. Par- 
 ticular attention should therefore be given to the length of 
 
THE MODERN CLOCK. 
 
 i6i 
 
 O 
 
 Fig. 51. 
 
l62 THE MODERN CLOCK. 
 
 this fan and if the stop of the escape wheel seems too ab- 
 rupt, the fan should be lengthened. 
 
 Figs. 50 and 51 show the same escapement with a four- 
 legged wheel instead of the double three-legged. In this 
 case, where there is but one wheel, the pallets must of ne- 
 cessity work on opposite sides of the wheel and hence they 
 are not planted in the same plane with each other, but are 
 placed as close to each side of the wheel as is practicable. 
 
 To lay out this escapement, draw the circle of the escape 
 wheel as before, make your line of centers and mark off on 
 the circle 6yy2° on each side of the line of centers and draw 
 radii to these points, which will indicate the approximate 
 position of the stops. Tangents to these radii, meeting above 
 the wheel on the line of centers will give the theoretical 
 point of the suspension. One set of the lifting pins is 
 planted on radii to the acting faces of the teeth of the es- 
 cape wheel. The opposite set, on the other side of the wheel, 
 is placed midway between the first set. This secures the 
 lifting at the line of centers. The wheel turns 45° at each 
 beat and its arbor likewise carries a fly. 
 
 In case the locking is not secure, the stops may be shifted 
 a little up or down, care being taken to keep them 135° 
 apart. In this way a draw may be given to the locking of 
 the scape wheel arms similar to the draw of the pallets in 
 a detached lever escapement and thus any desired resistance 
 to unlocking may be secured. The stops in either escape- 
 ment are generally made of steel and it is of the utmost, im- 
 portance that. the arms of the escape wheel should leave them 
 without imparting the least suspension of an impulse. 
 Therefore, the stops and the ends of the arms should be cut 
 aAvay (backed off) to rather a sharp angle to insure clear- 
 ance when the arms are leaving the stops. It is also of 
 equal importance that the legs of the wheels should fall on 
 the stops dead true. The fit of each of the legs should be 
 examined on both stops with a powerful eye glass, so that 
 they should be correct and also see that when the unlock- 
 ing takes pl?ce the wheel is absolutely free to turn. 
 
CHAPTER XII. 
 
 THE CYLINDER ESCAPEMENT AS APPLIED TO CLOCKS. 
 
 We remarked in a previous chapter that the Hfting planes 
 were sometimes on the wheel and sometimes on the anchor. 
 In another chapter we pointed out clearly that the run on the 
 locking surface of the pallets had an important bearing on 
 the freedom of the escapement and hence on the rate of the 
 dead beat escapement. In considering the cylinder escape- 
 ment, so common in carriage clocks, we shall find t'tiat the 
 lift is almost entirely on the curved planes of the escape 
 wheel, and that the locking planes are greatly extended, so 
 that they form the outer and inner surfaces of the cylinder 
 walls. Thus \ve have here a form of the dead beat escape- 
 ment, which embraces but one tooth of the escape wheel 
 and is adapted to operate a balance instead of a pendulum. 
 Therefore the points for us to consider are as before, the 
 amount of lift, lock, drop and run, and the shapes of our 
 escape wheel teeth to secure the least friction, as our lock- 
 ing surfaces (the run) being so greatly extended this mat- 
 ter becomes important. 
 
 Action of the Escapement. — Fig. 52 is a plan of the cyl- 
 inder escapement, in which the point of a tooth of the escape 
 wheel is pressing against the outside of the shell of the 
 cylinder. As the cylinder, on which the balance is mounted, 
 is moved around in the direction of the arrow, the wedge- 
 shaped tooth of the escape wheel pushes into the cylinder, 
 thereby giving it impulse. The tooth cannot escape at the 
 other side of the cylinder, for the shell of the cylinder at 
 this point is rather more than half a circle ; but its point 
 locks against the inner side of the shell and runs there till 
 
 163 
 
164 
 
 THE MODERN CLOCK. 
 
 the balance completes its vibration and returns, when the 
 tooth which was inside the cylinder escapes, giving an im- 
 pulse as it does so, and the point of the succeeding tooth 
 is caught on the outside of the shell. The teeth rise on 
 stalks from the body of the escape wheel, and the cylinder 
 is cut away just below the acting part of the exit side, leav- 
 
 Fig. 52. a, wheel; b, cylinder; f, stalk on which teeth are mounted. 
 
 ing for support of the balance only one-fourth of a circle, 
 in order to allow as much vibration as possible. This will 
 be seen very plainly on examining Fig. 53, which is an ele- 
 vation of the cylinder to an enlarged scale. 
 
 Proportion of the Escapement.— The escape wheel has 
 fifteen teeth, formed to give impulse to the cylinder during 
 from 20° to 40° of its vibration each way. Lower angles 
 are as a rule used with large than with small-sized escape- 
 
THE MODERN CLOCK. 
 
 165 
 
 rrtents, but to secure the best result either extreme must be 
 avoided. In the escapement with very slight inclines to the 
 wheel teeth, the first part of the tooth does no work, as the 
 tooth drops on to the lip of the cylinder some distance up 
 the plane. On the other hand, a very steep tooth is almost 
 sure to set in action as the oil thickens. The diameter of 
 
 Fig. 53. 
 
 the cylinder, its thickness and the length of the wheel teeth 
 are all co-related. The size of the cylinder with relation to 
 the wheel also varies somewhat with the angle of impulse, 
 a very high angle requiring a slightly larger cylinder than 
 a low one. If a cylinder of average thickness is desired for 
 an escapement with medium impulse, its external diameter 
 may be made equal to the extreme diameter of the escape 
 wheel multiplied by 0.T15 
 
66 
 
 THE MODERN CLOCK. 
 
 Then to set out the escapement, if a Hft of say 30° be 
 decided on, a circle on which the points of the teeth will 
 fall is drawn within one representing the extreme diameter 
 of the escape wheel, at a distance from it equal to 30'' of 
 the circumference of the cylinder. Midway between these 
 
 \i^' \ \ < 
 
 V30» -i 
 
 Fig. 54, 
 
 two circles the cylinder is planted (see Fig. 54). If the 
 point of one tooth is shown resting on the cylinder, a space 
 of half a degree should be allowed for freedom between 
 the opposite side of the cylinder and the heel of the next 
 tooth. From the heel of one tooth to the heel of the next 
 equal 24° of the circumference of the wheel, 360-^15=24°, 
 and from the point of one tooth to the point of the next 
 
THE MODERN CLOCK. 167 
 
 also equals 24° so that the teeth may now be drawn. They 
 are extended within the innermost dotted circle to give them 
 a little more strength, and their tips are rounded a little, 
 having the points of the impulse planes on the inner or 
 basing circle. The backs of the teeth diverge from a rad- 
 ial line from 12° to 30°, in order to give the cylinder clear- 
 ance, a high angled tooth requiring to be cut back more 
 than. a low one. A curve whose radius is about two-thirds 
 that of the wheel is suitable for rounding the impulse planes 
 of the teeth. The internal diameter of the cylinder should 
 be such as to allow a little freedom for the tooth. The 
 rule in fitting cylinders is to have equal clearance inside and 
 outside, so as to equalize the drop. The acting part of the 
 shell of the cylinder (where the lips are placed) should be 
 a trifle less than seven-twelfths of a whole circle, with the 
 entering and exit lips which are really the pallets, rounded 
 as shown in the enlarged plan, Fig. 55, the entering lip or 
 pallet rounded both ways and the exit pallet rounded from 
 the inside only. This rounding of the lips of the cylinder 
 adds a little to the impulse beyond what would be given 
 by the angle on the wheel teeth alone. The diameter of 
 the escape wheel is usually half that of the balance, rather 
 under than over. 
 
 Size of Cylinder Pivot. — To establish the size of the 
 pivot with relation to its hole i^ apparently an easy thing to 
 do correctly, but to an inexperienced workman it is not so. 
 The side shake in cylinder pivot holes should be greater 
 than that for ordinary train holes ; one-sixth is the amount 
 prescribed by Saunier ; the size of the pivot relatively to the 
 cylinder about one-eighth the diameter of the body of the 
 cylinder. It is very necessary that this amount of side 
 shake should be correctly recognized ; if less than the amount 
 stated, the escapement, though performing well while the 
 oil is fresh, fails to do so when it commences to thicken. 
 
 When the balance spring is at rest, the balance should 
 
THE MODERN CLOCK. 
 
 69 
 
 have to be moved an equal amount each way before a tooth 
 escapes. By gently pressing against the fourth wheel with 
 a peg this may be tried. There is generally a dot on the 
 balance and three dots on the plate to assist in estimating 
 the amount of lift. When the balance spring is at rest, the 
 dot on the balance should be opposite to the center dot on 
 the plate. The escapement will then be in heat, that is, pro- 
 vided the dots are properly placed, which should be tested. 
 Turn the balance from its point of rest till a tooth just drops, 
 and note the position of the dot on the balance with refer- 
 ence to one of the outer dots on the plate. Turn the bal- 
 ance in the opposite direction till a tooth drops again, and 
 if the dot on the balance is then in the same position with 
 reference to the other outer dot, the escapement will be in 
 beat. The two outer dots should mark the extent of the 
 lifting, and the dot on the balance would then be coincident 
 with them as the teeth dropped when tried in this way ; but 
 the dots may be a little too wide or too close, and it will 
 therefore be sufficient if the dot on the balance bears the 
 same relative position to them as just explained ; bnt if it 
 is found that the lift is unequal from the point of rest, the 
 balance spring collet must be shifted in the direction of the 
 least lift till the lift is equal. A new mark should then be 
 made on the balance opposite to the central dot on the 
 plate. 
 
 When the balance is at rest, the banking pin in the balance 
 should be opposite to the banking stud in the cock, so as to 
 give equal vibration on both sides. This is important for 
 the following reason. The banking pin allows nearly a 
 turn of vibration and the shell of the cylinder is but little 
 over half a turn, so that as the outside of the shell gets round 
 towards the center of the escape wheel, the point of a tooth 
 may escape and jam the cylinder unless the vibration is 
 pretty equally divided. When the banking is properly ad- 
 justed, bring the balance round till the banking pin is 
 against the stud; there should then be perceptible shakL' 
 
170 THE MODERN CLOCK. 
 
 between the cylinder and the plane of the escape wheeL Try 
 this with the banking- pin, first against one and then against 
 the other side of the stud. If there is no shake, the wheel 
 may be freed by taking a little off the edge of the passage 
 of the cylinder where it fouls the wheel, by means of a sap- 
 phire file, or a larger banking pin may be substituted at the 
 judgment of the operator. See that the banking pin and 
 stud are perfectly dry and clean before leaving them : a 
 sticky banking often stops a clock when nearly run down. 
 Cylinder timepieces, after going for a few months, some- 
 times increase their vibration so much as to persistently 
 bank. To meet this fault a weaker mainspring may be 
 used, or a larger balance, or a wheel with a smaller angle 
 of impulse. By far the quickest and best way is to very 
 slightly lap the wheel by holding a piece of Arkansas stone 
 against the teeth, afterwards polishing with boxwood and 
 red stuff. So little taken off the wheel in this way as to be 
 hardly perceptible will have great effect. 
 
 Sometimes the escape wheel has too much end shake. We 
 must notice in the first place how the teeth are acting in the 
 cylinder slot. Suppose, when the escape wheel is resting 
 upon its bottom shoulder, the cylinder will ride upon the 
 plane of the wheel, which will cause it to kick or give the 
 wheel a trembling motion, then we know that the cylinder 
 is too low for the wheel ; therefore, we have not only to 
 lower the escape top cock in order to correct the end shake, 
 but we must also drive the bottom cylinder plug out a little 
 in order to raise the cylinder sufficient to free it from the 
 plane of the wheel. Now, if the end shake of the cylinder is 
 correct previous to this, we shall now either have to raise 
 the cock or drive the top plug in a little. But suppose the 
 end shake of the escape pinion is excessive, and is, when the 
 bottom shoulder is resting on the jewel, a little too low so 
 that the bottom of the escape wheel runs foul of the cylinder 
 shell ; in this case we simply drive out the steady pins from 
 the bottom escape wheel cock and file a piece off the cock, 
 
TilE MODERN CLOCK. lyi 
 
 leaving it perfectly flat when we have enough ofi. We then 
 insert the steady pins again, screw it down, and if the end 
 shake is right, the escapement is mostly free and right also. 
 
 Now let us consider the frictions ; there is the resistance 
 of the pivots, which depends on their radius, on the weight 
 of the balance, the balance spring, the collet, and the weight 
 of the cylinder; these are called locking frictions. Then 
 there are those of the planes, of the teeth of the wheel, of the 
 lips of the cylinder. It is on these that the change and de- 
 struction of the cylinder are produced. To prevent this 
 destruction, it is necessary to render the working parts 
 of the cylinder very hard and well polished, as well as the 
 teeth of the escape wheel. 
 
 The oil introduced in the cylinder is also a cause as in the 
 dead beat. It may thicken; the dust proceeding from the 
 impact of the escapement forms with the oil an amalgam 
 which wears the cylinder. The firmness and constancy of 
 the cylinder depend on the preservation and fluidity of the 
 oil. 
 
 Then there are the accidental frictions ; the too close 
 opening of the cylinder, the play of the balance and of the 
 wheel, with the thickening of the oil, changes the arc of 
 vibration a good deal; the teeth of the wheel may not be 
 sufficiently hollowed, so that the cylinder can revolve in the 
 remaining space, for the oil with the dust forms a thickness 
 which also changes the vibration. The drop should not be 
 too great, for it is increased by the thickening of the oil 
 and impedes the vibration. 
 
 Examination of Clocks. — In this particular escape- 
 ment, when used for larger timepieces than watches, it is 
 astonishing the variety of methods which are employed, yet 
 the same results are expected. In examining such clocks 
 we will first notice that the chariot, cock, etc., are so placed, 
 many of them, that the last wheel in the train is a crown 
 wheel, hence it is made to work at 90° with the escape wheel 
 
I'Ji THK MODEIIN CLOCK. 
 
 pinion which is set at right angles with the crown wheel 
 pinion, and, as a matter of course, the cylinder is also set 
 the same way. Now, this arrangement needs especial care, 
 for it is quite natural that when the entire friction of the 
 cylinder is only on the bottom part of the bottom pivot, the 
 clock is sure to go faster than when the whole length of 
 both pivots are more in contact with their jewel holes, w^hich 
 is always the case when the cylinder is parallel with all the 
 pinions, instead of standing upon one pivot only. Now, al- 
 though there must of necessity be a very great difference in 
 timing the clock in the two different positions, yet we find 
 no difference in the strength of mainspring or any part of 
 the train, which is a mistake, for the result is simply this: 
 the clock will gain time for the first few days after wind- 
 ing, and will then gradually go slower and slower until the 
 mainspring is entirely exhausted. It is not very difficult to 
 ascertain why it goes so fast after winding, for then the 
 whole tension of the spring is on, and as there is not suffi- 
 cient friction on the point of one pivot to counteract this, 
 the banking pin is almost sure to knock, and will continue to 
 knock for the first few days until a part of the spring's 
 pressure is exhausted. Now, in this case the knocking of 
 the banking pin alone would cause the clock to gain time, 
 even if the extra tension of the mainspring did not assist it 
 to do so. Hence, on the whole, the result is anything but 
 satisfactory, for such a clock can never be properly brought 
 to time. 
 
 Having said this much about the fault (which is entirely 
 through the want of a little forethought with the manu- 
 facturer), I will give as good a remedy as I can suggest 
 to give the reader an idea of how these faults may be put to 
 right, if he is willing to spend the time upon them. In the 
 first place take out the cylinder and make the bottom pivot 
 oerfectly flat instead of leaving it with a round end, as they 
 are mostly left, which only allows just one part of the pivot 
 to be in contact with the endstone. By leaving this pivot 
 
THE MODERN CLOCK. I73 
 
 flat on the bottom, there is more surface in contact ; hence, 
 in a sense, more friction. 
 
 In some cases the whole pivot left flat would not be 
 sufficient to retard the mainspring's force; then we must 
 resort to other methods to effect a cure. 
 
 Well, our next method in order to try and get the clock 
 to be a uniform timekeeper, is to change the mainspring for 
 one well finished and not quite so strong as the original 
 one. Perhaps some will say "why not do this before we go 
 to the trouble of flattening the bottom pivot?" Just this; 
 when a pivot • is working only upon the bottom it is best 
 to have a flat surface to work upon, as the balance is then 
 oscillated with more uniformity, even when the mainspring 
 is not exactly uniform in its pressure; therefore we do no 
 harrur-but good^by making the bottom pivot flat, and this 
 alone will sometimes be sufficient to cure the fault of the 
 banking knocking if nothing else. 
 
 To my mind, when such strong mainsprings are used as 
 we generally see in this class of timepiece, neither of the 
 jewel holes or pivots should be so small as they usually are. 
 Fancy such small pivots as are mostly seen upon the escape 
 wheel pinion being driven by such a strong mainspring. 
 If we allow the clock to run down while the escape wheel 
 is in place, we are very liable to find one or both pivots 
 broken off before it gets run down. I think all such pivots 
 ought to be sufficiently strong to stand the pressure of the 
 mainspring through the train of wheels without coming to 
 grief. But there is another reason why these pivots are 
 liable to get broken off while letting the train run down ; that 
 is, the badly pitched depth we often find in the crown wheel 
 and escape wheel pinion. We frequently find too much 
 end shake to the' crown wheel which, while resting one 
 shoulder of the arbor against the plate puts the depth too 
 deep, and on the other shoulder the depth is too shallow. 
 l^QW, when the train is running rapidly this crown wheel is 
 jumping about in the escape wheel pinion, so that the rough- 
 
174 THE MODERN CLOCK. 
 
 ness of the running all helps to break off the escape wheel 
 pivots. The best way to correct this depth is to notice how 
 the screws fit in the cylinder plate — for these screws have 
 to act as steady pins as well. If the holes where the screws 
 go through are at all large, we then notice which would be 
 the most convenient side to screw it securely in order to put 
 a collet upon the shoulder of the crown wheel so that the 
 depth will be right by making the end shake right with only 
 fixing a collet to one shoulder. This depth, when correct, 
 will also cause a more uniform pressure upon the escape- 
 ment, and help to make the clock keep better time. We are 
 supposing that this crown wheel is perfectly true, or it is not 
 much use trying to correct the depth as mentioned above, 
 for even if the end shake be ever so exact and the wheel 
 teeth are out of true, we shall never get the depth to act as 
 it ought, neither can the clock be depended upon for keep- 
 ing going, regardless of keeping time. When this crown 
 wheel is out of true it is best to rivet it true, not do as I 
 h;ive seen it done, placed in the lathe and topped true, and 
 then the teeth rounded up by hand. This n]ethod simply 
 means a faulty depth after all, for in topping the teeth, those 
 teeth which require the most topping will, when they are 
 finished, be shorter from the top to the base than those 
 v;hich do not get topped so much; therefore, some of the 
 teeth are longer than the others, while the shorter ones are 
 thicker ; for when the wheel was originally cut the teeth were 
 all cut alike. These remarks will apply to several kinds of 
 wheels; for whenever a wheel is topped to put it true, we 
 may depend w^e are making a very faulty wheel of it unless 
 we have a proper wheel cutting machine. 
 
 The crown wheel must not be too thick because we will 
 find the tooth to act with the inner edge, and what is left 
 outside only endangers touching the pinion leaf which is 
 next to come into action. Make sure the escape pinion is 
 not too large, whicji sometimes happens. If it is, it must 
 be reduced in size, or better, put in a new one. The crown 
 
THE MODERN CLOCK. 
 
 175 
 
 wheel holes must fit nicely and the end shake be well ad- 
 justed. Do not spare any trouble in making this depth as 
 perfect as you are able, as most stoppages happen through 
 the faults in this place. It would be advisable, when sure 
 the depth is correct, to drill two steady pin holes through 
 the escapement plateau into the edge of the plates. When 
 steady pins are inserted this will always ensure the depth 
 being right when put together. 
 
 In some of these clocks it is not only the crown wheel, 
 but frequently the escape wheel has too much end shake. 
 The former, as I have said, can be corrected by making a 
 small collet that will just fit over pivot, fasten it on 
 friction tight, place the wheel in the lathe and turn 
 the collet down until it is the same size as the other part of 
 the arbor, then run off the end to the exact place for the end 
 shake to be right. If it is properly done and a steel collet is 
 used, it will not be detected that a collet has been put on. 
 Now, when the escape wheel end shake is wrong we have to 
 proceed differently under different circumstances for we 
 must notice in the first place how the teeth are acting in 
 the cylinder slot. 
 
 See that the cylinder and wheel are perfectly upright. 
 Suppose, when the escape wheel is resting upon its bottom 
 shoulder, the cylinder will ride upon the plane of the wheel, 
 which will cause it to kick or give the wheel a. trembling 
 motion, then we know that the cylinder is too low for the 
 wheel ; therefore, we have not only to lower the escape top 
 cock in order to correct the end shake, but we must also 
 drive the bottom cylinder plug out a little in order to raise 
 the cylinder sufficient to free it from the plane of the wheel. 
 Now, if the end shake of the cylinder is correct previous to 
 this, we shall either have to raise the cock or drive the top 
 plug in a little. But suppose the end shake of the escape 
 pinion is excessive, and is, when the bottom shoulder is 
 resting on the jewel, a little too low so that the bottom of 
 the escape wheel runs foul of the cylinder shell ; in this case 
 
176 THE MODERN CLOCK. 
 
 we simply drive out the steady pins from bottom escape 
 wheel cock and file a piece off the cock, leaving it perfectly 
 flat when we have got enough off. We then insert the 
 steady pins again, screw it. down, and, if the end shake is 
 right, the escapement is mostly free and right also. It some- 
 times happens that the wheel is free of neither the top nor 
 bottom plug, but should this be the case, suflicient clearance 
 may be obtained by deepening the opening with a steel pol- 
 isher and oilstone dust or with a sapphire file. A cylinder 
 with too high an opening is bad, for the oil is drawn away 
 from the teeth by the escape wheel. 
 
 If a cylinder pivot is bent, it may very readily be straight- 
 ened by placing a bushing of a proper size over it. 
 
 These clocks are very good for the novice to exercise his 
 skill in order to thoroughly understand the workings of the 
 horizontal escapement. He is better able to see how the 
 different parts act with each other than he is in the small 
 watch. When the escape is correct he will find that the 
 plane of the escape wheel will work just in the center of 
 the small slot in the cylinder. 
 
 If he will notice how the teeth stand in the cylinder when 
 the banking pin is held firmly upon the fixed banking pin, 
 it will give him an idea of how this should be. At one side 
 the lip of the cylinder is just about to touch the inside of the 
 escape tooth, but the banking pin just prevents it from doing 
 so, while on the other side the cylinder goes round just 
 far enough to let the point of the next tooth just get on the 
 edge of the slot, but it cannot get in owing to the interven- 
 tion of the banking pin. If this is allowed to get in the slot 
 just here, we then have what is called "a locking," which 
 is, in reality, an overturned banking. If the other side is so 
 that the banking pin does not stop it soon enough, the edge 
 of the slot knocks upon the inside of the teeth and causes a 
 trembling of the escape wheel, and the clock left in this 
 form will never keep very good time. We may easily 
 remedy this by taking off the hair spring collet; holding the 
 
THE MODERN CEOCK. 
 
 77 
 
 cylinder firmly in the plyers, and with the left hand turn 
 the balance a little outwards; this will bring the banking 
 pins in contact before the cylinder touches the inside of the 
 wheel teeth, and all is right, providing we are careful in 
 not doing it too much ; if so, we shall find the banking 
 knock — a fault which is quite as bad, if not worse, than the 
 one we are trying to remedy. Those particulars are the 
 most important of anything in connection with the cylinder 
 escapement. Yet, as this kind of clock is now being made 
 up at such a low price, these seem^ing little items aie fre- 
 quently overlooked ; hence, when they get into the hands 
 of the inexperienced, there is often more trouble with them 
 
 Fig. 56. 
 
 than there need be if they knew where to look for some of 
 the faults which I have been endeavoring to bring to light, 
 There are several other things in connection with this par- 
 ticular clock, but we will not comment further just now, 
 but take them up when we are considering the trains, etc. 
 
 In the meantime we will resume our study of the cylinder 
 escapement with particular reference to badly worn or other- 
 wise ill fitting escape wheels, as m.any times, the other points 
 being right, the wheel and cylinder may be such as to give 
 either too great or too small a balance vibration. 
 
 A poor motion can also be due to a rough or a badly pol- 
 ished cylinder, but such a cylinder wc rarely find. That 
 with a wrong shape of the C3dinder lips the motion is not 
 much lessened can be seen in quite ordinary movements 
 where the quality is certainly not of the best neither are 
 the lips correctly formed, nevertheless they have rather an 
 
178 THE MODERN CLOCK. 
 
 excessive motion. To cover up these defects in such move- 
 ments the cylinder wheel teeth are purposely given the shape 
 as shown at B in Fig. 56, and to give sufficient power a 
 strong mainspring is inserted. 
 ' With an excessive balance vibration we can usually con- 
 clude that it is an intentional deception on the part of the 
 manufacturer, while a poor motion can generally be ascribed 
 to careless methods in making. The continued efforts in 
 making improvements to quicken and cheapen manufactur- 
 ing processes very frequently result in the introduction of 
 defects which are only found by the experienced and practi- 
 cal watchmaker 
 
 As to the causes which induce excessive balance vibra- 
 tions? As this defect is generally found in the cheaper 
 grades of cylinder escapements, having usually rather small, 
 heavy, and often clumsy balances, those which have balances 
 whose weight is probably less than they ought to be, need 
 not here be further considered, and it only remains for us 
 to look to the cylinder or the escape wheel for the causes 
 which produce these excessive vibrations. It will be found 
 that the cylinder is smaller in diameter than usually em- 
 ployed in such a size of clock ; the escape wheel is naturally 
 also smaller, and its teeth generally resemble B, Fig. 56, 
 while A shows the correct shape of a tooth for a wheel of 
 that diameter. 
 
 In using small cylinders we can give the escape wheel 
 teeth a somewhcit greater angle of inclination than gener- 
 ally used, but thnt tlic proper amount of incline is exceeded 
 is proved by the fact that the balance vibrates more than 
 two-thirds of a turn, it can also be readily seen that with a 
 tooth like B a greater impulse must be imparted than one 
 with an easy curve like A, and the impulse is still further 
 increased as the working width of the tooth B (the lift) is 
 greater, indicated by line h, w^iile the same line in a correct 
 width of tooth, as shown at a, is considerably shorter. 
 
THE MODERN CLOCK. 
 
 179 
 
 In addition to what has been said of these escapements, w^ 
 also find them provided with very strong mainsprings to 
 give the necessary power to a tooth hke B with its steeply 
 inclined lifting face or impulse angle. 
 
 To decrease the great amplitude of ^he balance vibrations 
 many watchmakers simply replace the strong mainspring 
 with a weaker one. But this proceedure is not advantageous 
 as the power of the escape wheel tooth is insufficient to 
 start the balance going and this is due to two causes. First, 
 the great angle of the escape wheel tooth, and secondly, the 
 inertia of the balance. It is only by violently shaking such 
 a clock that, we are enabled to start it going. And the 
 
 Fig. 57. 
 
 Fig. 58. 
 
 owner soon becomes dissatisfied from its frequent stoppage 
 due to setting of the hands and other causes so that he will 
 be often obliged to shake it until it starts going once more. 
 For properly correcting these defects the best method to 
 pursue is to replace the cylinder wheel with another one, 
 whose teeth are of the shape as shown at Fig. 55 and with- 
 out question a good workman will always replace the 
 escape wheel if the clock is of fair quality. But if a low 
 grade one, we would hardly be justified in going to the ex- 
 pense of putting in new wheels, as the low prices for which 
 these clocks are sold preclude such an alteration. As we 
 must improve the wheel some way to get a fair escapement 
 action we can place it in a lathe and while turning, hold 
 
l8o THE MODERN CLOCK. 
 
 an oil stone slip against it, we can remove the point S, Fig. 
 56. After removing- the point the tooth will now have the 
 form as shown at tooth C, Fig. 57. We now take a thin 
 and rather broad watch mainspring, bending a part straight 
 and holding it in the line / /, and revolving the wheel in the 
 direction as shown b}^ the arrow, its action being indicated 
 by figures i to 8; beginning at the point of the tooth at i, 
 at 2 it comes in contact with the whole of the lifting face, 
 and from 3 to 8 only on the projecting corner which was left 
 by the oil stone slip in removing the heel of the tooth. In 
 this way all the teeth are acted upon until the corner is en- 
 tirely removed. Of course oil stone dust and oil is first 
 used upon the spring for grinding, after which the teeth are 
 polished with diamantine. Care must be observed in using 
 the spring so as not to get the end / too far into the tooth 
 circle, as it would catch on the heel of the preceding tooth. 
 
 After the foregoing operation has been completed any 
 feather edge remaining on the points of the teeth must be 
 removed with a sapphire file and polished ; we will now have 
 a tooth as indicated by D, Fig. 57. This shape of tooth can 
 hardly be said to be theoretically correct, nevertheless it 
 is a close approximation of the proper form of tooth, which 
 is shown by the dotted lines, and will then perform its func- 
 tions much better than in its original condition.. 
 
 Fig. 58 also shows how the spring must be moved from 
 side to side — indicated by dotted lines — so that the lifting 
 face will have a gentle curve instead of being flat ; R repre- 
 sents the tooth. 
 
 After the wheel has been finished, as described, and again 
 placed in the clock, it will be found that the balance makes 
 only two-thirds of a turn, and as a result the movement can 
 be easier brought to time and closely regulated. 
 
 In the above I have described the cause of excessive bal- 
 ance vibration, the method by which it can be corrected, and 
 in what follows I shall endeavor to make clear the reasons 
 for a diminished balance vibration or poor motion. It has 
 
THE MODERN CLOCK. l8l 
 
 been probably the experience of most watchmakers to 
 repair small cylinders of a low grade, having a poor motion 
 or no motion at all, and it would hardly be profitable to 
 expend much time in repairing them. But considerable 
 time is often wasted in improving the motion by polishing 
 pivots and escape wheel teeth, possibly replacing the cap 
 jewels, or even the hole jewels, increasing the escapement 
 depth or making it shallower, examining the cylinder and 
 finding nothing defective, and as a last effort putting in a 
 stronger mainspring. But all in vain, the balance seems 
 tired and with a slight pressure upon an arm of the center 
 wheel it stops entirely. 
 
 Fig. 59. 
 
 In this case, as in a former one, in fact, it is necessary 
 at all times to carefully examine the cylinder wheel. j\Iy 
 reason for not considering the cylinder itself so much as the 
 wheel is that the makers of them have made a considerable 
 advance in their methods of manufacture, so we find the 
 cylinders fairly well made and generally of the correct size. 
 Even if the cylinder is incorrectly sized, either too large oi 
 small, it does not necessarilv follow that the watch would 
 have a bad motion, as I have frequently had old movements 
 where the cylinder was incorrectly proportioned and yet the 
 motion was often a good, satisfactory one. Generally 
 speaking, the cylinder escapement is one which admits of the 
 worst possible constructive proportions and treatment, as 
 we have often examined such clocks when left for repairs, 
 
l82 THE MODERN CLOCK. 
 
 that, notwithstanding their being full of dirt, worn cylinder, 
 broken jewel holes, etc., they have been running until one 
 of the cylinder pivots has been completely worn away. 
 
 It only remains to look for the source of the trouble in the 
 escape wheel. If we examine the wheel teeth carefully, we 
 shall find them resembling those in Fig. 59, the dotted lines 
 representing the correct shape of the teeth for a wheel of 
 that diameter. 
 
 Why do we find wheels having such defective teeth ? This 
 is probably due to their rapid manufacture, as they very 
 likely had the correct shape when first cut, but by careless 
 grinding and polishing they were gfiven improper forms, 
 careless treatment being very evident at tooth F, which we 
 find on examination has a feather edge at the point as well 
 as at the heel of the tooth. If we grind these edges of the 
 tooth with a ruby file, by placing it in the position as indi- 
 cated by dotted lines h and /i^, and afterwards polishing the 
 tooth point, we will find that the balance makes a better 
 vibration. A wheel, having teeth like E, can still be used, 
 but the balance will have a very poor motion, due to the fact 
 that the impulse angle of the wheel tooth is too small ; the 
 impulse faces of the teeth having so small an angle, are near- 
 ly incapable of any action. With a tooth like G, if we 
 should remove its bent point at the dotted line d, then th^ 
 tooth would be too short, and as the inclination of the im- 
 pulse face is incapable to produce a proper action, a new 
 wheel must be used, having teeth as shown at Fig. 55. 
 
 The reasons why a tooth, having the shape as shown at 
 F and G (Fig. 59), will cause a bad action of the escapement 
 and also why in such cases with a greater force acting on 
 the wheel, causes a stopping of the clock, I will endeavor 
 to explain with the aid of the illustration Fig. 60. Here we 
 clearly see the curved points of the- teeth resting against the 
 outer and inner walls of the cylinder while the escapement is 
 in action. 
 
THE MODERN CLOCK. 
 
 183 
 
 Teeth H and H^ represent the defective tooth, while K 
 and K^ shows a correctly formed tooth for a wheel of the 
 same size, the correct depth and positions where the tooth 
 strikes the inner and outer walls of the cylinder. It will be 
 readily seen that the position of the tooth point upon the 
 cylinder (at c) is most favorable in reducing the resistance 
 to the least possible amount. But in the case of the teeth H 
 and H^ the condition is entirely different. We find that it 
 v/as necessary to set the escapement very deeply in order 
 that it could perform its functions at all, and, as a conse- 
 
 Fig 
 
 quence, we have a false proportion ; the effects being con- 
 siderably increased by the worst possible position of the 
 teeth H and H^, where they touch the cylinder. While the 
 cylinder c is turning in the direction shown by the arrows 
 i i^j the tooth does not affect the cylinder to any extent ; but 
 during the reverse movement of the cylinder, in the direction 
 of 0^, an excessive amount of engaging friction must take 
 place. A close inspection of the drawing will enable us to 
 see that there is a great tendency of the cylinder to drag 
 the tooth along with it during each of these motions. It is 
 evident that in such a case the friction will eventually be- 
 come so great as to lock the escapement, and if greater 
 pressure is applied by any means to teeth H and H^, it is 
 easily seen that this eifect will take place much. more rapidly. 
 Replacing the escape wheel with one of correctly formed 
 teeth and size is the best means at our disposal. 
 
CHAPTER XIII. 
 
 THE DETACHED LEVER ESCAPEMENT AS APPLIED TO CLOCKS. 
 
 As the clcck repairer is almost of necessity a watch- 
 maker, or hopes to become one, and as he must enter deeply 
 into the study of all questions pertaining to the detached 
 lever in its various forms before he can make any progress 
 at all in watchmaking, it w^ould seem unnecessary to repeat 
 in these pages that which has already been so well said and 
 so perfectly drr.\vn, described and illustrated by such author- 
 ities as Moritz Grossman, Britten, Playtner and the various 
 teachers in the horological schools, to say nothing of an 
 equally brilliant and more numerous coterie of writers 
 among the French, Germans and Swiss, so that the reader 
 is referred to these writers for the mathematics and draw- 
 ings which already so fully cover the technical and theo- 
 retical properties of the detached lever escapement. A few 
 words as to its adaptation to clocks may, however, not be 
 out of place. 
 
 Anyone who sees the clocks of to-day would be inclined 
 to suppose that the first clocks wxre constructed with pendu- 
 lums, because this is evidently the most simple and reliable 
 system for clocks, and that the employment of the balance 
 has been suggested by the necessity for portable time pieces. 
 This is, however, not the case, for the first clocks had a 
 verge escapement with a crude balance consisting of tw^o 
 arms, carrying shifting weights for regulation. The pendu- 
 lum Avas not used until about three hundred years after the 
 invention of the first clock. 
 
 After the invention of the dead beat escapement, with its 
 great gain in accuracv by the reduction of the arc of pendu- 
 lum oscillation, attempts were made to combine its many 
 virtues with the necessarily large vibrations of a balance and 
 
 184 
 
THE MODERN CLOCK. 
 
 '85 
 
 thus get all the advantages of both systems. By placing the 
 lever on the arbor of the anchor, it was possible to multiply 
 the small angle of impulse on the pallets very considerably 
 at the balance, and to make all connection between them 
 cease immediately after the impulse had been given. The 
 dead beat escapement was thus converted into the detached 
 lever escapement and the latter made available for both 
 watches and clocks. Another important feature of this 
 
 OE 
 
 n 
 
 u 
 
 no: 
 
 3E 
 
 fl 
 
 U 
 
 Fig. 61. Pin Escapement for Clocks. 
 
 escapement is that when properly proportioned it will not set 
 on the locking or lifting, but will start to go as soon as 
 power is applied to the escape wheel through the train. This 
 cannot be said of the cylinder, duplex, or detent escape- 
 ments, and it will be seen at once that this has an important 
 influence upon the cost of construction, which must always 
 be considered in the manufacture of cheap clocks in enor- 
 mous quantities. 
 
l86 THE MODERN CLOCK. 
 
 The lever escapement with pins for pallets and the lifting 
 planes on the teeth of the escape wheel, which is the one 
 usually put into cheap clocks, is from the theoretical point 
 of view a very perfect form, because its lifting and locking 
 lake place at exactly the same center distance and at the 
 same angles, which again allows for greater latitude in 
 cheap construction, while still maintaining a reasonably 
 accurate rate of performance. These are the main reasons 
 why the pin anchor has such universal use in cheap clocks. 
 
 As this escapement is generally centered between the 
 plates, banking pins are dispensed with by extending the 
 counterpoise end of the lever far enough so that its crescent 
 shaped sides will perform that office by banking against the 
 scape wheel arbor; see Fig. 6i. The fork end of the lever 
 engages with an impulse pin carried in the balance and the 
 balance arbor is cut away to pass .the guard point or dart, 
 thus doing away with the roller table. In other constructions 
 the roller table is supplied in the shape. of a small brass collet 
 which carries the pin and has a notch for the guard point, 
 thus making a single roller escapement. 
 
 The diameter of the lifting pins is generally made equal to 
 2^ degrees of the scape wheel, which gives a lift of 2 de- 
 grees on the pallet arms, and the remainder of the lift, 63^ 
 degrees, must be performed by the lifting planes 
 of the wheel teeth. The front sides of the wheel 
 teeth are generally made with 15 degrees of draw and the 
 lever should bank when the center of the pin is just a little 
 past the locking corner of the tooth. Other details of the 
 pin anchor escapement coincide with the ordinary pallet 
 form, as used in watches, and the reader is referred for them 
 to the works of the various authors mentioned previously. 
 
 The trouble with the majority of these clocks is in the 
 escapement and balance pivots, and to these parts are we 
 going to direct particular attention, for often, be it ever so 
 clean, the balance gets up a sort of ''caterpillar motion" that 
 is truly distressing, and if no more is done we may expect 
 
THE MODERN CLOCK. 187 
 
 a ''come back" job in a very short time. In taking down 
 the movement the face wheels are left in place, but some- 
 times it may be necessary to remove the "set wheel" of the 
 alarm in order to proceed as we do. Remove the screws or 
 pins that hold the plates together in the vicinity of the 
 escapement, leaving the others, though if screws they may 
 be loosened slightly; pry up the corner of the plate over 
 the lever to loosen one pivot of same and let it drop away 
 from the scape wheel sufficiently to let the wheel revolve 
 until it is locked by a wire or pegwood previously inserted 
 in the train, after which the plates can be pried apart more 
 conveniently to permit the lever being removed entirely, also 
 the scape wheel and the one next following. As nickel 
 clocks differ in make-up, the operator must, of course, exer- 
 cise judgment as to the work in hand to accomplish this. 
 
 Have ready a straight-sided tin pail, with cover, that will 
 hold at least one-half gallon of gasoline and of diameter 
 large enough to receive the largest brass clock; remove 
 the wire or pegwood and immerse the clock into the fluid 
 and allow it to run down; this will loosen all the dirt and 
 gummy oil and clean the clock very effectually. Let it re- 
 main long enough for all the dirt to settle to the bottom of 
 the pail ; then remove and wipe as dry as possible with a 
 soft rag ; by having no binder on the spring it is permitted 
 to uncoil to its full, and thereby remove all gummy oil be- 
 tween its coils. Now peg out the holes of the wheels re- 
 moved and of the lever and 'that portion of our work is 
 complete. 
 
 Polish or burnish the pivots of wheels either in a split 
 chuck in the lathe, or by holding in a pin vise, resting the 
 pivot on a filing block (an ivory one is best), and revolving 
 between the fingers, using a smooth back file for burnishing, 
 after the manner of pointing up a pin tongue, only let the 
 file be held flat, so as to maintain a cylindrical pivot as nearly 
 as possible. The scape wheel is now polished, i. e., the teeth, 
 with a revolving bristle wheel on a polishing lathe, charged 
 
l88 THE MODERN CLOCK. 
 
 with kerosene oil and tripoli. This will smooth up the teeth 
 in fine form, especially those wheels that work into a lever 
 with pin pallets. Clean the scape wheel by dipping into 
 gasoline to remove all the oil and tripoli. The other wheel 
 may simply be brushed in the gasoline or dipped and then 
 brushed dry. 
 
 We now turn our attention to the lever and closely ex- 
 amine the pallets with a glass; if there are the least signs 
 of wear upon them they must be removed. If the lever with 
 pin pallets it is better to remove the steel pins and insert new 
 ones. See if the holes in the anchor where they are inserted 
 will admit a punch to drive them out from the back ; if not, 
 open these holes with a drill until the ends of the pins are 
 reached. Put a hollow stump with a sufficiently large hole 
 in the staking tool, and by placing the pins in the stump 
 they can be driven out successively, being sure that the 
 driving punch is no larger than the pins ; drive or insert into 
 their places a couple of needles of the proper size, and then 
 break off at correct lengths; this completes the job in this 
 particular style of lever. 
 
 With the other style the job is not quite so easy ; with a 
 pair of small round-nose pliers grasp the brass fork close up 
 to the staff and bend it back from the pallets till it lays 
 parallel with the staff; treat the counter poise of the fork 
 in like manner ; place a thin zinc lap into the lathe, charged 
 with flour of emery, and with the fingers holding the pallets 
 grind off all wheel teeth marks on both the impulse and lock- 
 ing faces of the pallets. Then polish with a boxwood lap 
 charged with diamantine. It is surprising how speedily this 
 can be done if laps are at hand. The only care necessary 
 is not to round off the corners of the pallets, and as they are 
 so large they can be easily held flat against the laps with 
 the thumb and finger as before stated. Bend back the fork 
 and counterpoise to their original position. The fork must 
 now be attended to; see that no notches are worn in the 
 horns of the fork by the steel impulse pin in the balance ; if 
 
THE MODERN CLOCK. 189 
 
 the}^ appear they must be dressed out and polished, also ex- 
 amine and smooth if necessary the ends of the horns that 
 bank against the balance staff. These may seem small mat- 
 ters, but they are often what cause all the trouble. 
 
 We now come to the balance staff and the hardened 
 screws in which the staff vibrates ; their irregularities are 
 often the source of much vexation, and there is only one 
 way to go at it and that is with a will and determination to 
 make it right. Examine the points of the staff and see if 
 they are in their normial shapes and are sharp and bright ; if 
 so they will probably do their work. But we will suppose 
 we have a bad case in hand and will therefore treat it thor- 
 oughly according to our method. We find the staff is large 
 in diameter and the ends are very blunt; the notch in the 
 center has a burr on each side as hard as glass, making an 
 admirable cause for catching the horns of the fork in some 
 of the vibrations or in a certain position ; also the round part 
 of the staff back of the notch is rough and looks as if it never 
 had been finished, and, in fact, it has not, for it truly appears 
 as if half, if not all, the nickel clocks are made to be finished 
 by the watchmaker. - Remove the hairspring and place the 
 staff between the jaws of your bench vise, with the jaws 
 close up to the staff, but not gripping it, the balance ''hub" 
 resting on the jaws with the impulse pin also down between 
 the jaws. Have a block of brass about one-fourth inch 
 square ; rest it on top of the staff, or on its pivot end, if it 
 may so be called, holding it with the thumb and finger of 
 the left hand. Strike this block with a hammer and drive 
 out the staff ; a hollow punch is apt to be split in doing this, 
 and as the pivot is to be re-pointed no harm will be done to 
 ihc pivot or to the end of the staff. Draw the temper so it 
 will work easily, insert into a split chuck and turn up new 
 points ; have them long and tapering, that is, turn the points 
 to a long slant from the end of the staff to the body of same, 
 or at least twice as much taper as they generally have; 
 polish off the back of the notch or round part of the staff 
 
190 
 
 THE MODERN CLOCK. 
 
 with an oil stone slip. Remove from the chuck, smear all 
 over with powdered boracic acid by first wetting the staff in 
 water, and then heat to a bright red and plunge straight into 
 water; it will now be white and hard; draw the temper 
 from the staff in the vicinity of the notch, leaving the pivot 
 points hard as before; re-insert into the chuck and with 
 diamantine polish the points and also around the staff in the 
 vicinity of the notch. The drawing of the temper from the 
 center of the staff to a spring temper is to make it less 
 liable to breakage while driving on the balance. Fasten 
 the staff tight in the vise and with a rather stout brass tube, 
 large enough to step over the largest staff, drive on the 
 balance to its former position. 
 
 If the workman has a pivot polisher with a large lap, the 
 job may be done, without softening the staff or removing 
 the balance, by grinding the pivots. In turning the staff we 
 often find it almost impossible to hold true. We straighten 
 the best we can and then turn up our pivots, and as long as 
 the untruth of the staff will not cause the balance to wabble 
 to such an extent as to give us a headache or cause us to 
 look cross-eyed it will do. W« do not -wish to be misunder- 
 stood or to give the impression that we go on the principle 
 of "good enough" ; but as gold dollars cannot be bought for 
 seventy-five cents, neither can a workman devote the time to 
 have everything perfect for fifty cents ; and for this very 
 reason do they come in such an unfinished state from the 
 mianufacturers. 
 
 Next see if the two screws in which the balance vibrates 
 have properly cut countersinks ; if rough or irregular, better 
 at once draw the temper, re-drill with a sharp-angled drill 
 and again harden. 
 
 Occasionally a bunch of these clocks will come in with 
 both pivots and cones badly rusted. This has generally been 
 caused by acid pickling, or some sort of chemical harden- 
 ing at the factory ; the acid or alkali gets into the pores of 
 the steel and comes out after the clock has been shipped. 
 
THE MODERN CLOCK. 
 
 191 
 
 They are generally made in such quantities that fifty or a 
 hundred thousand of them have been distributed before 
 finding out that they were not right and then it is a matter 
 of two or three years before the factory hears the last of it. 
 The trouble is attributed to bad oil, or to anything else but 
 the hardening, which is the real cause, and the expense of 
 taking back and refitting the balance arbors and cones, 
 paying freight both ways . and standing the abuse of dis- 
 gruntled jewelers, goes on until life becomes anything but 
 a -bed of roses. Every jeweler should warn the factory im- 
 mediately on finding rust in the cones of a shipment of new 
 clocks and not attempt to fix them himself, as such a fault 
 cannot be discovered at the factory and every day it con- 
 tinues means more thousands of clocks distributed that will 
 give trouble. 
 
 Our clock is now ready to be put together. Wind up the 
 spring and slip on the binder; then put in the wheels and 
 lever ; then adjust the balance and hairspring to their proper 
 places, slightly wind the mainspring and then see (by bring- 
 ing either horn against the staff) whether it sticks and holds 
 the balance ; if so, shorten the fork slightly by bending ; try 
 this until the balance and fork act perfectly free and safe. 
 Slightly oil the balance pivots; an excess will only gather 
 dust and prove detrimental, as the countersinks form an ad- 
 mirable place for holding the dust. Now oil the remaining 
 parts and we are sadly mistaken if our clock does not make 
 a motion that will be gratifying. 
 
 The foregoing process may seem tedious and uncalled for 
 and too close m.ention made of the lesser portions of the 
 work, but we must not ''despise the day of small things," 
 and as we are watchmakers, we are expected to do this 
 work, even though troublesome and the pay small ; we 
 should also bear in mind that if we only make a nickel 
 clock run and keep fair time, it will be a large advertise- 
 ment, and possibly repay tenfold. It takes only an hour to 
 
192 THE MODERN CLOCK. 
 
 do this job complete, while in many cases only the balance 
 staff needs attention. 
 
 Sometimes such a clock will be apparently all right me- 
 chanically but will continue to lose time ; then it is probable 
 'that the balance does not make the proper number of vibra- 
 tions, which causes the clock to lose time. There is one way 
 to tell this, which will soon locate the trouble: count 
 the train to ascertain the number of vibrations the balance 
 should make in one minute. You do this by counting the 
 number of teeth in the center wheel, which we will say is 48; 
 third wheel 48; fourth wheel, 45; escape, 15. Multiply all 
 teeth together, which give us 48x48x45x15 = 1,555,200. 
 Now count the leaves in the third wheel pinion, which is 
 6 ; fourth, 6 ; escape, 6. Multiply these together, 6x6x6 = 
 216; now divide the leaves into the teeth, 1,555,200^-216 
 = 7,200, w^hich is the number of whole vibrations some An- 
 sonia alarm clocks make in one hour. Dividing 7,200 by 60 
 gives us 120, the number of vibrations per minute. Now the 
 balance must make 120 vibrations in one minute, counting 
 the balance going one way. If the balance only vibrates 
 118, the clock will lose time and the hairspring must be 
 taken up or made shorter, until it makes the required num- 
 ber of vibrations. If it should vibrate 122 the clock would 
 gain ^nd the hairspring should be let out. 
 
 Find out the number of vibrations your balance should 
 make and work accordingly; and if you find that the bal- 
 ance makes the proper number of vibrations in one minute, 
 then the trouble must lie in the center post, which has not 
 enough friction to carry the hands and dial wheels, or the 
 wheel that gears into the hour wheel and regulates the 
 alarm hand is too tight and holds back the hands. You 
 should find some trouble about these wheels or center post, 
 for where a balance makes the proper number of vibrations 
 in one minute, the minute hand cannot help going around 
 if everything else is correct. 
 
THE MODERN CLOCK. 
 
 193 
 
 Fig. 62 illustrates the escapement of the Western Clock 
 Manufacturing Company for their cheap levers. It has 
 hardened steel pallets placed in a mould and the fork cast 
 around them, thus insuring exact placing of the pallets, and 
 the company claim that they thus secure a detached lever 
 escapement with all the advantages of hardened and polished 
 pallets at a minimum cost. 
 
 Mr. F. Dauphin, of Cassel, Germany, on page 387 of Der 
 Deutsche Uhrmacher Zeitung, 1905, has described a serious 
 fault of some of the cheap American alarm clocks in the 
 
 Fig. 62. 
 
 depthings of the escapements and how he remedied it by 
 changing the position of the pins. It is to be regretted that 
 Mr. Dauphin did not state the measurements of the parts as 
 nearly as possible in this article and also give the manu- 
 facturer's name, simply to enable others not as skilled as he 
 is to do what I would do in such a case ; namely, to return 
 it to the jobber and get a new and correct movement in its 
 stead free of charge. The American clock manufacturers 
 are very liberal in this respect and never hesitate to take 
 back a movement that was not correct when it leff the fac- 
 tory, even when the customer, in the attempt to correct it, 
 has spoiled it ; spoiled or not, it goes to the waste pile any- 
 way, when it reaches the factory. I seriously doubt the 
 ability of the average watch repairer to correctly change the 
 position of the pins as suggested; and to change the center 
 of action of the lever is certainly a desperate job. I here- 
 vvith give a correct drawing of an escape wheel and lever, 
 
194 
 
 THE MODERN CLOCK. 
 
 such as are used in the above cited clocks, made from meas- 
 urements of the parts of a clock. The drawing is, of 
 course, enlarged. The measurements are: Escape wheel, 
 actual diameter, i8.ii mm.; original diameter, 17 mm.; 
 fever, from pin to pin, outside, 9.3 mm.; distance of cen- 
 ters of wheel and lever, lo.o mm. I found that all these 
 measurements almost exactly agree with Grossmann's 
 tables, and I do not doubt at all that they were taken from 
 
 them. There is only one mistake visible, which is in the 
 shape of the escape teeth, and I fail to see why this was 
 overlooked by those in charge at the factory: the drazv is 
 insufficient. It is only from seven to eight degrees, when 
 it should be fifteen degrees. I show this at tooth A, in the 
 drawing, where you can see both dotted lines, measuring 
 the angle of draw ; line C as it is and line B as it should be. 
 Notwithstanding the deficient draw, this escapement will 
 work safely as long as the pivot holes are not too large, or 
 t\^orn sideways ; but if you want to make it safe you should 
 file the locking faces of teeth slightly under ; even if you 
 
THE MODERN CLOCK. I95 
 
 do not make a model job, you have remedied the fault. 
 Make a disk of i8.ii mm. diameter, put it on the arbor of 
 the wheel and lay a straight edge from the point of the 
 tooth to the center of the disk, so as to see how much it 
 needs to be filed away. Even if this undercutting is not 
 very true it will go. 
 
 To Measure Wheels with Odd Numbers of Teeth. 
 — This is a job that so frequently comes to the watchmaker 
 who has to replace wheels or pinions that the following 
 simple method should be generally appreciated. It de- 
 pends upon the fact that the radius of a circle, R, Fig. 64, 
 equals the versed sine E (dotted) plus the cosine B. If 
 we stand such a wheel on the points of the teeth, A C, and 
 measure it we shall get the length of the line T B only, 
 when what we really need is the length of the lines T B E, 
 to give us the real diameter for our wheel, and E we find has 
 been cut away, so that we cannot measure it. Say it is a 
 15-tooth escape wheel, then by standing the old wheel up on 
 the anvil of a vertical micrometer, resting it on two of its 
 teeth, as shown in Fig. 64, the measuring screw can be 
 brought in contact with the tooth diametrically opposite the 
 space between the two teeth on the anvil, and a measure- 
 ment taken, which will be less than the full diameter by the 
 versed sine of 12 degrees (half the angle included between 
 two adjoining teeth). By bringing each tooth in succession 
 to the top, such a wheel could be measured in fifteen differ- 
 ent directions, which would vary slightly, owing to the fact 
 that some of the teeth may be bent a little, but the mean 
 of these measures should be what the wheel would measure 
 were the teeth in their original shape. If a tooth was badly 
 bent the three measures in which it was involved could be 
 rejected, and the mean of the other twelve measures taken 
 as the correct value and found to be, we will say, 0.732 inch. 
 Consulting a table of natural sines the cosine of 12 degrees 
 is found to be 0.97815, which subtracted from i gives 
 
196 
 
 THE MODERN CLOCK. 
 
 0.02185 as the versed sine. Multiplying this by 0.36 inch 
 (practically one-half of our measured 0.732) to get the 
 approximate radius of the wheel, we get 0.008 inch, the 
 amount to be added to the micrometer measurement in 
 order to get the diameter of the blank. 
 
 At first sight it may appear like a vicious principle that 
 we must know the radius of the wheel before we can deter- 
 
 oi. Cjctting the fuU diameter. 
 
 mine the value of the correction in question, but we only 
 need to know the radius approximately in order to determine 
 the correction very closely, an error of 1-20 inch in the as- 
 sumed value of the radius producing an error of only o.ooi 
 inch in the value of the correction. 
 
 This method can of course be applied to all wheels and 
 pinions to get the size of the blank; with other wheels than 
 escape wheels, where the pitch line and the full diameter 
 do not coincide, the addendum may be subtracted from the 
 full diameter to get the pitch line. 
 
 Cutters for Clock Trains. — In cutting escape wheels 
 or others with wnde space between the teeth, it is a matter 
 
THE MODERN CLOCK. 
 
 97 
 
 of some difficulty with many people to enable them to set 
 the cutter properly. 
 
 Mr. E. A. Sweet calls attention to the fact that if a cutter 
 be set so that its center touches the circumference of the 
 wheel to be cut, said cutter will be in the proper position for 
 work. For instance, if an escape wheel is to be cut, it is 
 sufficient to set the cutter in such a manner that that portion 
 of the cutter forming the bottom of the cut touch the cir- 
 cumference of the blank at the center of the cutter. It may 
 then be backed off and fed in with the certainty of being 
 properly placed. 
 
CHAPTER XIV. 
 
 PLATES^ PIVOTS AND TIME TRAINS. 
 
 Before going further with the mechanism of our clocks 
 we will now consider the means by which the various mem- 
 bers are held in their positions, namely, the plates. Like 
 most other parts of the clock these have undergone various 
 changes. They have been made of wood, iron and brass 
 and have varied in shapes and sizes so much that a great 
 deal may be told concerning the age of a clock by examining 
 the plates. 
 
 Most of the wooden clocks had wooden plates. The 
 English and American movements were simply boards of 
 oak, maple or pear with the holes drilled and bushed with 
 brass tubes — full plates. The Schwarzwald movements 
 were generally made with top and bottom boards and 
 stanchions, mortised in between them to carry the trains, 
 which were always straight-line trains. The rear stanchions 
 were glued in position and the front ones fitted friction- 
 tight, so that they could be removed in taking down the 
 clock. This gave a certain convenience in repairmg, as, for 
 instance, the center (time) train could be taken down with- 
 out disturbing the hour or quarter trains, or vice versa. 
 Various attempts have been made since to retain their con- 
 venience with brass plates, but it has always added so much 
 to the cost of manufacture that it had to be abandoned. 
 
 The older plates were cast, smoothed and then ham- 
 mered to compact the metal. The modern plate is rolled 
 much harder and stiflfer and it may consequently be much 
 thinner than was formerly necessary. The proper thickness 
 of a plate depends entirely upon its use. Where the move- 
 ment rests upon a seat board in the case and carries the 
 
THE MODERN CLOCK. I99 
 
 weight of a heavy penduhim. attached u one of the plates 
 they must be made stiff enough to furnish a rigid support 
 for the pendulum, and we find them thick, heavy and with 
 large pillars, well supported at the corners, so as to be very 
 stiff and solid. An example of this may be seen in that 
 class of regulators which carry the pendulum on the move- 
 ment. Where the pendulum is light the plates may there- 
 fore be thin, as the only other reason necessary for thick- 
 ness is that they may provide a proper length of bearing for 
 the pivots, plus the necessary countersinking to retain the 
 oil. 
 
 In heavy machinery it is unusual to provide a length of 
 box or journal bearing of more than three times the diam- 
 eter of the journal. In most cases a length of twice the 
 diameter is more than sufficient; in clock and other light 
 work a "square" bearing is enough ; that is one in which 
 the length is equal to the diameter. In clocks the pivots are 
 of various sizes and so an average must be found. This is 
 accomplished by using a plate thick enough to furnish a 
 proper bearing for the larger pivots and countersinking the 
 pivot holes for the smaller pivots until a square bearing is 
 obtained. This countersinking is shaped in such a manner 
 as to retain the oil and as more of it is done on the smaller 
 and faster moving pivots, where there is the greatest need 
 of lubrication, the arrangement works out very nicely, and 
 it will be seen that with all the lighter clocks very thin plates 
 may be employed while still retaining a proper length of 
 bearing in the pivot holes. 
 
 The side shake for pivots should be from .002 to .004 of 
 an inch; the latter figure is seldom exceeded except in 
 cuckoos and other clocks having exposed w^eights and 
 pendulums. Here much greater freedom is necessary as 
 the movement is exposed to dust which enters freely at the 
 holes for pendulum and weight chains, so that such a clock 
 would stop if given the ordinary amount of side shake. 
 
20O THE MODERN CLOCK. 
 
 We are afraid that many manufacturers of the ordinary 
 American clock aim to use as thin brass as possible for 
 plates without paying too much attention to the length of 
 bearing. If a hole is countersunk it will retain the oil 
 when a flat surface will not. The idea of countersinking to 
 obtain a shorter bearing will apply better to the fine clocks 
 than to the ordinary. In ordinary clocks the pivots must be 
 longer than the thickness of the plates for the reason that 
 freight is handled so roughly that short pivots will pop out 
 of the plates and cause a lot of damage, provided the springs 
 are wound when the rough handling occurs. 
 
 It will be seen by reference to Chapter VII (the mechan- 
 ical elements of gearing), Figs. 21 to 25, that a wheel and 
 pinion are merely a collection of levers adapted to con- 
 tinuous work, that the teeth may be regarded as separate 
 levers coming into contact with each other in succession; 
 this brings up two points. The first is necessarily the rela- 
 tive proportions of those levers, as upon these will depend 
 the power and speed of the motion produced by their action. 
 The second is the shapes and sizes of the ends of our levers 
 so that they shall perform their work with as little friction 
 and loss of power as possible. 
 
 To Get Center Distances. — As the radii and circum- 
 ferences of circles are proportional, it follows that the 
 lenoths of our radii are merely the lengths of our levers 
 '"^ce Fig, 24), and that the two combined (the radius of 
 the wheel, plus that of the pinion) will be the distance at 
 which we must pivot our levers (our staffs or arbors of our 
 wheels) in order to maintain the desired proportions of 
 their revolution. Consequently we can work this rule back- 
 wards or forwards. 
 
 For instance if we have a wheel and pinion which must 
 work together in the proportion of 7^ to i ; then 7^ -f- i 
 =r Sy2; and if we divide the space between centers into 8>4 
 spaces we will have one of these spaces for the radius of the 
 
THE MODERN CLOCK. 20I 
 
 i?ifch circle of the pinion and 7^. for the pitch circle of the 
 wheel, Fig. 65. This is independent of the number of teeth 
 so long as the proportions be observed ; thus our pinion may 
 have eight teeth and the wheel sixty, 60 -f- 8 := 7.5, or 
 75 -^ 10 =: 7.5, or 90-f- 12 = 7.5, or any other combination 
 of teeth which will make the correct proportion between 
 them and the center distances. The reason is that the teeth 
 are added to the wheel to prevent slipping, and if they did 
 not agree with each other and also with the proportionate 
 distance between centers there would be trouble, because 
 the desired proportion could not be maintained. 
 
 Now we can also work this rule backwards. Say we 
 have a wheel of 80 teeth and the pinion has 10 leaves but 
 they do not work together well in the clock. Tried in the 
 depthing tool they work smoothly. 80 -^- 10 := 8, conse- 
 quentty our center distance must be as 8 and i. 8 -]- i = 95 
 the wheel must have 8 parts and the pinion i part of the 
 radius of the pitch circle of the wheel. IMeasure carefully 
 the diameter of the pitch circle of the v^/heel ; half of that is 
 the pitch radius, and nine-eighths of the pitch radius is the 
 proper center distance for that wheel and pinion. 
 
 Say we have lost a wheel ; the pinion has 12 teeth and we 
 know the arbor should go seven and one-half times to one 
 of the missing wheel; we have our center distances estab- 
 lished by the pivot holes which are not worn; what size 
 should the wheel be and how many teeth should it have ? 
 12 X 7-5 = 90, the number of teeth necessary to contain 
 the teeth of the pinion 7.5 times. 7.5 -[- i = 8.5, the sum of 
 the center distances ; the pitch radius of the pinion can be 
 closely measured ; then 7.5 times that is the pitch radius of 
 the missing wheel of 90 teeth. Other illustrations with other 
 proportions could be added indefinitely but we have, we 
 think, said enough to make this point clear. 
 
 Conversion of Numbers. — There is one other point 
 which sometimes troubles the student who attempts to fol- 
 
202 
 
 THE MODERN CLOCK. 
 
 low the expositions of this subject by learned writers and 
 that is the fact that a mathematician will take a totally 
 difterent set of numbers for his examples, without explain- 
 ing why. If you don't know why you get confused and fail 
 to follow him. It is done to avoid the use of cumbersome 
 fractions. To use a homely illustration: Say we have 
 one foot, six inches fo^ cur wheel radius and 4.5 inches for 
 
 Fig. G5. Spacing off center di-tances; c, ce:; cr of wlieel; e, pitch circle; 
 d, dedenduni; b, addendum; a, center of pinion. 
 
 our pinion radius. If we turn the foot into inches we have 
 18 inches. 18 -f- 4.5 = 4, which is simpler to work with. 
 Now the same thing can be done with fractions. In the 
 above instance we got rid of our larger unit (the foot) by 
 turning it into smaller units (inches) so that we had only 
 one kind of units to work with. The same thing can be done 
 with fractions ; for instance, in the previous example we 
 can get rid of our mixed numbers by turning everything 
 
THE MODERN CLOCK. 203 
 
 into fractions. Eighteen inches equals 36 halves and 4.5 
 equals 9 halves ; then 36 -f- 9 = 4. This is called the con- 
 version of numbers and is done to simplify operations. For 
 instance in watch work we may find it convenient to turn all 
 our figures into thousands of a millimeter, if we are using 
 a millimeter gauge. Say we have the proportions of 7.5 to 
 I to maintain, then turning all into halves, 7^. X 2 = 15 
 and 1X2 = 2. 15 + 2=17 parts for our center distance, 
 of which the pitch radius of the pinion takes 2 parts and that 
 of the wheel 15. 
 
 The Shapes of the Teeth. — The second part of our 
 problem, as stated above, is the shapes of the ends of our 
 levers or the teeth of our wheels, and here the first consid- 
 eration which strikes us is that the teeth of the wheels ap- 
 proach each other until they meet; roll or slide upon each 
 other until they pass the line of centers and then are drawn 
 apart. A moment's consideration will show that as the 
 teeth are longer than the distance between centers and are 
 securely held from slipping at their centers, the outer ends 
 must either roll or slide after they come in contact and that 
 this action will be much more severe while they are being 
 driven towards each other than when they are being drawn 
 apart after passing the line of centers. This is why the 
 engaging friction is more damaging than the disengaging 
 friction and it is this butting action which uses up the power 
 if our teeth are not properly shaped or the center distances 
 not right. Generally speaking this butting causes serious 
 loss of power and cutting of the teeth when the pivot holes 
 are worn or the pivots cut, so that there is a side shake of 
 half the diameter of the pivots, and bushing or closing the 
 holes, or new and larger pivots are then necessary. This is 
 for common, work. For fine work the center distances 
 should be restored long before the wear has reached this 
 point. 
 
204 THE MODERN CLOCK. 
 
 If we take two circular pieces of any material of different 
 diameters and arrange them so that each can revolve around 
 its center with their edges in contact, then apply power to 
 the larger of the two, we find that as it revolves its motion 
 i-s imparted to the other, which revolves in the opposite 
 direction, and, if there is no slipping between the two sur- 
 faces, with a velocity as much greater than that of the larger 
 disc as its diameter is exceeded by that of the larger one. 
 We have, then, an illustration of the action of a wheel and 
 pinion as used in timepieces and other mechanisms. It 
 would be impossible, however, to prevent slipping of these 
 smooth surfaces on each other so that power (or motion) 
 would be transmitted by them very irregularly. They simply 
 represent the "pitch" circles or circles of contact of these 
 two mobiles. If now we divide these two discs into teeth 
 so spaced that the teeth of one will pass freely into the 
 spaces of the other and add such an amount to the diameter 
 of the larger that the points of its teeth extend inside the 
 pitch circle of the smaller, a distance equal to about i^ 
 times the width of one of its teeth, and to the smaller so 
 that its teeth extend inside the larger one-half the width of 
 a tooth, the ends of the teeth being rounded so as not to 
 catch on each other and the centers of revolution being kept 
 the same distance apart, on applying power to the larger of 
 the two it will be set in motion and this motion will be im- 
 parted to the smaller one. Both will continue to move with 
 the same relative velocity as long as sufficient power is 
 applied. Other pairs of mobiles may be added to these to 
 infinity, each addition requiring the application of increased 
 power to keep it in motion. 
 
 These pairs of mobiles as applied to the construction of 
 timepieces are usually very unequal in size and the larger 
 is designated as a "wheel" while the smaller, if having less 
 than 20 teeth, is called a "pinion" and its teeth "leaves." 
 Now while we have established the principle of a train of 
 wheels as used in various mechanisms, our gearing is very 
 
THE MODERN CLOCK. 
 
 205 
 
 defective, for while continuous motion may be transmitted 
 through such a train, we will find that to do so requires 
 the application of an impelling force far in excess of what 
 should be required to overcome the inertia of the mobiles, 
 and the amount of friction unavoidable in a mechanism 
 where some of the parts move in contact with others. 
 
 This excess of power is used in overcoming a friction 
 caused by improperly shaped teeth, or when formed thus the 
 teeth of the wheel come in contact with those of the pinion 
 and begin driving at a point in front of what is known as the 
 "line of centers," i. e., a line drawn through the centers of 
 revolution of both mobiles, and as their motion continues the 
 driven tooth slides on the one impelling it toward the center 
 of the wheel. When this line is reached the action is re- 
 versed and the point of the driving tooth begins sliding on 
 the pinion leaf in a direction away from the center of the 
 pinion, which action is continued until a point is reached 
 where the straight face of the leaf is on a line tangential to 
 the circumference of the wheel at the point of the tooth. It 
 then slips off the tooth, and the driving is taken up on an- 
 other leaf by the next succeeding tooth. The sliding action 
 which takes place in front of the line of centers is called 
 "engaging," that after this line has been passed "disengag- 
 ing" friction. 
 
 Now we know that in the construction of timepieces, fric- 
 tion and excessive motive power are two of the most potent 
 factors in producmg disturbances in the rate, and that, while 
 som.e friction is unavoidable in any mechanism, that which we 
 have just described may be almost entirely done away with. 
 Let us examine carefully the action of a wheel and pinion, 
 and we will see that only that part of the wheel tooth is used, 
 which is outside the pitch circle, while the portion of the 
 pinion leaf on which it acts is the straight face lying inside 
 this circle, therefore it is to giving a correct shape to these 
 parts we must devote our attention. If we form our pinion 
 leaves so that the portion of the leaf inside the pitch circle 
 
206 
 
 THE MODERN CLOCK, 
 
 is a straight line pointing to the center, and give that por- 
 tion of the wheel tooth lying outside the pitch circle (called 
 the addenda, or ogive of the tooth) such a degree of curva- 
 ture that during its entire action the straight face of the 
 leaf will form a tangent to that point of the curve which it 
 
 Showing that a hypocycloid of 
 
 rcle is a straight line. 
 
 Generating an epicycloid curve for a cut pinion. D, generating circle. 
 Uotterl line epicycloid curve. Note how the shape varies with the 
 thickness of the tooth. 
 
 touches, no sliding action whatever will take place after the 
 line of centers is passed, and if our pinion has ten or more 
 leaves, the "addenda" of the wheel is of proper height, and 
 the leaves of the pinion arc net too thick, there will be no 
 contact in front of the I'ne of centers. With such a depth 
 the only friction would be from a slight adhesion of the 
 surfaces in contact, a factor too small to be taken into 
 consideration. 
 
THE MODERN CLOCK. 
 
 207 
 
 Here, then, we have an ideal depth. How shall we obtain 
 the same results in practice? It is comparatively an easy 
 matter to so shape our cutters that the straight faces of our 
 pinion leaves will be straight lines pointing to the center, 
 but to secure just the proper curve for the addenda of our 
 wheel teeth requires rather a more complicated manipula- 
 tion. This curve does not form a segment of a circle, for it 
 has no two radii of equal length, and if continued would 
 form, not a circle, but a spiral. To generate this curve, we 
 will cut from cardboard, wood, or sheet metal, a segment of 
 a circle having a radius equal to that of our zvheel, on the 
 pitch circle, and a smaller circle whose diameter is equal to 
 the radius of the pinion, on the pitch circle. To the edge of 
 the small circle we will attach a pencil or metal point so that 
 it will trace a fine mark. Now we lay our segment flat on a 
 piece of drawing paper, or sheet metal and cause the small 
 circle to revolve around its edge without slipping. We find 
 that the point in the edge of the small circle has traced a 
 series of curves around the edge of the segment. 
 
 These curves are called *V.p:cycloids," and have the pe- 
 culiar property that if a line be drawn through the generat- 
 ing point and the point of contact of the two circles, this will 
 always be at right angles to a tangent of the curve at its 
 [)oint of intersection. It is this property to which it owes its 
 value as a shape for the acting surface of a wheel tooth, 
 for it is owing to this that a tooth whose acting surface is 
 bounded by such a curve can impel a pinion leaf through 
 the entire lead with little sliding action between the two 
 surfaces. This, then, is the curve on which we will form 
 the addenda of our wheel teeth. 
 
 In Fig. 66, the wheel has a radius of fifteen inches and the 
 pinion a radius of one and one-half, and these two measure- 
 ments are to be added together to find the distance apart 
 of the two wheels; 16.5 inches is then the distance that the 
 centers of revolution are apart of the wheels. Now, the teeth 
 and leaves jointly act on one another to maintain a sure and 
 equable relative revolution of the pair. 
 
20^ THE MODERN CLOCK. 
 
 In Fig. 66, the pinion has its leaves radial to the center, 
 inside of the pitch line D, and the ends of the leaves, or those 
 parts outside of the pitch line, are a half circle, and serve no 
 purpose until the depthings are changed by wear, as they 
 never come in contact with the wheel ; the wheel teeth only 
 touch the radial part of the pinion and that occurs wholly 
 within the pitch line. So in all pinions above lo leaves in 
 number the addendum or curve is a thing of no moment, 
 except as it may be too large or too long. In many large 
 pieces of machinery the pinions, or small driven wheels, 
 have no addendum or extension beyond their pitch diameter 
 and they serve every end just as well. In watches there is 
 so much space or shake allowed between the teeth and 
 pinions that the end of a leaf becomes a necessitv to guard 
 against the pinion's recoiling out of time and striking its 
 sharp corner against the wheel teeth and so marring or 
 cutting them. In a similar pair of wheels in machinery there 
 are very close fits used and the shake between teeth is very 
 slight and does not allow of recoil, butting, or "running out 
 of time." 
 
 Running out of time is the sudden stopping and setting 
 back of a pinion against the opposite tooth from the one 
 just in contact or propelling. This, with pinions of sup- 
 pressed ends, is a fault and it is averted by maintaining the 
 ends. 
 
 The wheel tooth drives the pinion by coming in contact 
 with the straight flank of the leaf at the line of centers, that 
 is a line drawn through the centers of the two wheels ; cen- 
 ters of revolution. 
 
 The curve or end of the wheel tooth outside of the pitch 
 line is the only part of the tooth that ever touches the pinion 
 and it is the part under friction from pressure and slipping. 
 At the first point of contact the tooth drives the pinion with 
 the greatest force, as it is then using the shortest leverage it 
 has and is pressing on the longest lever of the leaf. As 
 this action proceeds, the tooth is acted on by the pinion leaf 
 
THE MODERN CLOCK. 
 
 209 
 
 farther out on the curve of the wheel tooth, thus length- 
 ening the lever of the wheel and at the same time the tooth 
 thus acts nearer to the center of the pinion by touching 
 the leaf nearer its center of revolution. 
 
 By these joint actions' it will^ appear that the wheel first 
 drives with the greatest force and then as its own leverage 
 lengthens and its force consequently decreases, it acts on a 
 shorter leverage of the pinion, as the end of a tooth, is nearer 
 to the center of the pinion, or on the shortest pinion lever- 
 age, just as the tooth is about ceasing to act. 
 
 The action is thus shown from the above to be a variable 
 one, which starts with a maximum of force and ends with a 
 minimum. Practically the variable force in a train is not 
 recognized in the escapement, as the other wheels and pin- 
 ions making up the train are also in the same relations of 
 maximum and minimum forces at the same time, and thus 
 this theoretical and virtual variability of train force is to a 
 great extent neutralized at the active or escaping end of the 
 movement. 
 
 There is another action between the tooth and leaf that is 
 not easy to explain without somewhat elaborate sketches of 
 the acting parts, and as this is not consistent with such an 
 article, we may dismiss it, and merely state that it is the 
 one of maintaining the relative angular velocities of the two 
 wheels at all times during their joint revolutions. 
 
 In Fig. 66 will be seen the teeth of the wheel, their 
 heights, widths and spacing, and the epicycloidal curves. 
 Also the same features of the pinion's construction. The 
 curve on the end of the wheel teeth is the only curve in 
 action during the rotation between wheel and pinion. Each 
 flank (both teeth and leaves) is a straight line to the 
 center of each. A tooth is composed of two members — the 
 pillar or body of the tooth inside of the pitch line and the 
 cvcloid or curve, wholly outside of this line. The pinion 
 also has two members, the radial flank wholly inside of the 
 pitch line, and its addendum or circle outside of this line. 
 
2IO 
 
 THE MODERN CI.OCK, 
 
 A' 
 
 yyiteelolf^ff 
 
 I .66 
 
THE MODERN CLOCK. 211 
 
 In Fig. 66 will be seen a tooth on the line of centers A B, 
 just coming in action against the pinion's flank and also one 
 just ceasing action. It will be seen that the tooth just enter- 
 ing is in contact at the joint pitches, or radii, of the two 
 wheels, and that when the tooth has run its course and 
 ceased to act, that it will be represented by tooth 2, Then 
 the exit contact will be at the dotted line o o. From this 
 may be seen just how far the tooth has, in its excursion, 
 shoved along the leaf of the pinion and by the distance the 
 line o o, is from the wheel's pitch line G, at this tooth. No. 2, 
 is shown the extent of contact of the wheel tooth. By these 
 dotted lines, then, it may be seen that the tooth has been 
 under friction for nearly its whole curve's length, while the 
 pinion's flank will have been under friction contact for less 
 than half this distance. In brief, the tooth has moved about 
 80-100 o'f its curved surface along the straight flank .35 of 
 the surface of the pinion leaf. From this relative frictional 
 surface may be seen the reason why a pinion is apt to be 
 pitted by the wheel teeth and cut away. In any case it 
 shows the relation between the two friction surfaces. In 
 part a wheel tooth rolls as well as slides along the leaf, but 
 whatever rolling there may be, the pinion is also equally 
 favored by the same action, which leaves the proportions of 
 individual friction still the same. 
 
 In Fig. 66 may be seen the spaces of the teeth and pinion. 
 The teeth are apart, equal to their own width and the depths 
 of the spaces are the same measurement of their width — that 
 is, the tooth (inside of the pitch line) is a pillar as wide as it 
 is high and a space between two teeth is of like proportions 
 and extent of surface. The depth of a space between two 
 teeth is only for clearance and may be made much less, as 
 may be seen by the pinion leaf, as the end of the circle does 
 not come half way to the bottom of a space. 
 
 The dotted line, o o, shows the point at which the tooth 
 comes out of action and the pointed end outside of this line 
 might be cut off without interfering with any function of 
 
212 THE MODERN CLOCK. 
 
 the tooth. They generally are rounded off in common clock 
 work. 
 
 The pinion is 3 inches diameter and is divided into twelve 
 spaces and twelve leaves; each leaf is two-fifths of the 
 width of a space and tooth. That is one-twelfth of the cir- 
 cumference of the pinion is divided into five equal parts and 
 the leaf occupies two and a space three of these parts. The 
 space must be greater than the width of a leaf, or the end of 
 a leaf w^ould come in contact with a tooth before the line 
 of centers and cause a jamming and butting action. Also 
 the space is needed for dirt clearance. As watch trains 
 actuated by a spring do not have any reserve force there 
 must be allowance made for obstructions between the teeth 
 of a train and so a large latitude is allowed in this respect, 
 more than in any machinery of large caliber. As will be 
 seen by Fig. 66, the spans between the leaves are deep, much 
 more so than is really necessary, and a space at O C shows 
 the bottom of a space, cut on a circle which strengthens a 
 leaf at its root and is the best practice. 
 
 Having determined the form of our curve, our next step 
 will be to get the proper proportions. Saunier recommends 
 that in all cases tooth and space should be of equal width, 
 but a more modern practice is to make the space slightly 
 wider, say one-tenth where the curve is epicycloidal. When 
 the teeth are cut with the ordinary Swiss cutters, which, of 
 course, cannot be epicycloidal, it is best to make the spaces 
 one-seventh wider than the tooth. This proportion will be 
 correct except in the case of a ten-leaf pinion, when, if we 
 w4sh to be sure the driving will begin on the line of centers, 
 the teeth must be as wide as the spaces ; but in this case 
 the pinion leaf is made proportionately thinner, so that the 
 requisite freedom is thus obtained. 
 
 The height of the addenda of the wheel teeth above the 
 pitch circle is usually given as one and one-eighth times the 
 width of a tooth. While this is approximately correct, it is 
 not entirelv so, for the reason that as we use a circle whose 
 
THE MODERN CLOCK. 213 
 
 diameter is equal to the pitch radius of the pinion for gen- 
 erating the curve, the height of the addenda would be differ- 
 ent on the same wheel for each different numbered pinion. 
 So that if a wheel of 60 were cut to drive a pinion of 8, the 
 curve of this tooth would be found too flat if used to drive 
 a pinion of 10. Now, since the pitch diameter of the pinion 
 is to the pitch diameter of the wheel as the number of leaves 
 in the pinion are to the number of teeth in the wheel, in 
 order to secure perfect teeth: we must adopt for the height 
 of the addenda a certain proportion of the radius or diameter 
 of the pinion it is to drive, this proportion depending on the 
 number of leaves in the pinion. 
 
 A careful study of the experiments on this subject with 
 models of depths constructed on a large scale, shows that 
 the proportions given below com.e the nearest to perfection. 
 
 When the pinion has six leaves the spaces should be twice 
 the width of the leaves and the depth of the space a little 
 more than one-half the total radius of the pinion. The ad- 
 denda of the pinion should be rounded, and should extend 
 outside the pitch circle a distance equal to about one-half 
 the width of a leaf. The addenda of the wheel teeth should 
 be epicycloidal in form and should extend outside the pitch 
 circle a distance equal to five-twelfths of the pitch radius 
 of the pinion. 
 
 With these proportions, the tooth will begin driving when 
 one-half the thicknesi- of a leaf is in front of the line of 
 centers, and there will be engaging friction from this point 
 until the line of centers is reached. 
 
 This cannot be avoided with low-numbered pinions with- 
 out introducing a train of evils more productive of faulty 
 action than the one we are trying to overcome. There will 
 be no disengaging friction. 
 
 When a pinion of seven is used, the spaces of the pinion 
 should be twice the width of the leaves, and the depth of a 
 space about three-fifths of the total radius of the pinion. 
 The addenda of the pinion leaves should be rounded, and 
 
214 THE MODERN CLOCK. 
 
 should extend outside the pitch circle about one-half, the 
 width of a leaf. The addenda of the wheel teeth should be 
 epicycloidal, and the height of each tooth above the pitch 
 circle equal to two-fiflhs of the pitch radius of the pinion. 
 'There is less engaging friction when a pinion of seven is 
 used than with one of six, as the driving does not begin 
 until two-thirds of the leaf is past the line of centers. There 
 is no disengaging friction. 
 
 With an eight-leaf pinion the space should be twice as 
 wide as the leaf, and the depth of a space about one-half the 
 total radius of the pinion. The addenda of the pinion leaves 
 should be rounded and about one-half the width of a leaf 
 outside the pitch circle. The addenda of the wheel teeth 
 should be epicycloidal, and the height of each tooth above 
 the pitch circle equal to seven-twentieths of the pitch radius 
 of the pinion. 
 
 With a pinion of eight there is still less engaging friction 
 than with one of seven, as three-quarters of the width of a 
 leaf is past the line of centers when the driving begins. As 
 there is no disengaging friction, a pinion of this number 
 makes a very satisfactory depth. 
 
 A pinion with nine leaves is sometimes, though seldom,, 
 used. It should have the spaces twice the width of the 
 leaves, and the depth of a space one-half the total radius. 
 The addenda should be rounded, and its height above the 
 pitch circle equal to one-half the width of the leaf. The 
 addenda of the wheel teeth should be epicycloidal, and the 
 height of each tooth above the pitch circle equal to three- 
 sevenths of the total radius of the pinion. With this pinion 
 the driving begins very near the line of centers, only about 
 one-fifth of the width of a leaf being in front of the line. 
 
 A pinion of ten leaves is the lowest number with which 
 we can entirely eliminate engaging friction, and to do so in 
 this case the proper proportions must be rigidly adhered to. 
 The spaces on the pinion must be a little more than twice 
 as w^de as a leaf; a leaf and space will occupy 36° of arc; 
 
THE MODERN CLOCK. 215 
 
 of this 11° should be taken for the leaf and 25° for the 
 space. The addenda should be rounded and should extend 
 about half the width of a leaf outside the pitch circle. The 
 depth of a space should be equal to about one-half the total 
 radius. For the wheel, the teeth should be equal in width 
 to the spaces, the addenda epicycloidal in form, and the 
 "height of each tooth above the pitch circle, equal to two- 
 fifths the pitch radius of the pinion. 
 
 A pinion having eleven leaves would give a better depth, 
 theoretically, than one of ten, as the leaves need not be made 
 quite so thin to ensure its not coming in action in front of 
 the line of centers. It is seldom seen in watch or clock 
 work, but if needed the same proportions should be used 
 as with one of ten, except that the leaves may be made a 
 little thicker in proportion to the spaces. 
 
 A pinion having twelve leaves is the lowest number with 
 which we can secure a theoretically perfect action, without 
 sacrificing the strength of the leaves or the requisite freedom 
 in the depths. In this pinion, the leaf should be to the space 
 as two to three, that is, we divide the arc of the circum- 
 ference needed for a leaf and space into five equal parts, 
 and take two of these parts for the leaf, and three for the 
 space; depth of the space should be about one-half the 
 total radius. The addenda of the wheel teeth should be 
 epicycloidal, and the height of each tooth above the pitch 
 line equal to two-sevenths the pitch radius of the pinion. 
 
 As the number of leaves is increased up to twenty, the 
 width of the space should be decreased, until when this 
 number is reached the space should be one-seventh wider 
 than the leaf. As these numbers are used chiefly for wind- 
 ing wheels in watches, where considerable strength is re- 
 quired, the bottoms of the spaces of both mobiles should be 
 rounded. 
 
 Circular Pitch. Diametral Pitch. — In large ma- 
 chinery it is usual to take the circumference and divide by 
 the number of teeth ; this is called the circular pitch, or dis- 
 
2l6 THE MODERN CLOCK. 
 
 tance from point to point of the teeth, and is useful for de- 
 scribing teeth to be cut out as patterns for casting. 
 
 But for all small wheels it is more convenient to take the 
 diameter and divide by the number of teeth. This is called 
 the diametral pitch, and when the diameter of a wheel or 
 pinion which is intended to work into it is desired, such 
 diameter bears the same ratio or proportion as the number 
 required. Both diameters are for their pitch circles. As 
 the teeth of each wheel project from the pitch circle and 
 enter into the other, an addition of corresponding amount 
 is made to each wheel ; this is called the addendum. As the 
 size of a tooth of the wheel and of a tooth of the pinion are 
 the same, the amount of the addendum is equal for both ; 
 consequently the outside diameter of the smaller wheel or 
 pinion will be greater than the arithmetical proportion be- 
 tween the pitch circles. As the diameters are measured pre- 
 sumably in inches or parts of an inch, the number of a 
 wheel of given size is divided by the diameter, which gives 
 the number of teeth to each inch of diameter, and is called 
 the diametral pitch. In all newly-designed machinery a 
 whole number is used and the sizes of the wheels calculated 
 accordingly, but when, as in repairing, a wheel of any size 
 has any number of teeth, the diametral number may have an 
 additional fraction, whicli docs not affect the principle but 
 gives a little more trouble in calculation. Take for ex- 
 ample a clock main wheel and center pinion : Assuming 
 the wheel to be exactly three inches in diameter at the pitch 
 line, and to have ninety-six teeth, the result will be 96-1-3 
 = ^2, or 32 teeth to each inch of diameter, and would be 
 called ^2 pitch. A pinion of 8 to gear with this wheel 
 would have a diameter at the pitch line of 8 of these thirty- 
 seconds of an inch or 8-32 of an inch. But possibly the 
 wheel might not be of such an easily manageable size. It 
 might, say, be 3.25 inches, in which case, 96 being the num- 
 ber of the wheel and 8 of the pinion, the ratio is 8-96 or 1-12, 
 so 1-12 of 3.25 := 0.270, the pitch diameter of the pinion. 
 
THE MODERN CLOCK. 217 
 
 These two examples are given to indicate alternative meth- 
 ods, the most convenient of which may be used. After 
 arriving at the true pitch diameters the matter of the adden- 
 dum arises, and it is for this that the diametral number is 
 specially useful, as in every case when figuring by this 
 system, whatever the number of a wheel or pinion, two of 
 the pitch numbers are to be added. Thus with the 32 pitch, 
 the outside diameter of the wheel will be 3 in. -f- 2-32, and 
 if the pinion 8-32 -}- 2-32 = 10-32. With the other method 
 the same exactness is more difficult of attainment, but for 
 practical purposes it will be near enough if we use 2-30 of 
 an inch for the addendum, when the result will be 3.25 -f- 
 2-30 or 33/4 -4- 2-30 = 31-3 in. nearly and the pinion 0.270 
 -f- 2-30 = 0.270 + .0666 = 0.3366 ; or to v/ork by 1-3 of 
 an inch is near enough, giving the outside diameter of the 
 pinion a small amount less than the theoretical, which is 
 always advisable for pinions which are to be driven. 
 
 We represent by Figs. 67 to 71 a wheel of sixty teeth 
 gearing with a pinion of six leaves. The wheel, whose 
 pitch diameter is represented by the line mm is the same ih 
 each figure. The pinion, which has for its pitch diameter 
 the line kk, is in Fig. 67, of a size proportioned to that of 
 the wheel, and its center is placed at the proper distance; 
 that is to say, the two pitch diameters are tangential. 
 
 In Fig. 68 the same pinion, of the proper size, has its 
 center too far off ; the depthing is too shallow. In Fig. 69 
 it is too deep. Figs. 70 and 71 represent gearing in which 
 the pitch circles are in contact, as the theory requires, but 
 the size of the pinions is incorrect. If the wheels and pinion 
 actuated each other by simple contact the velocity of the 
 pinion with reference to that of the wheel would not be 
 absolutely the same; but the ratio of the teeth being the 
 same, the same ratio of motion obtains in practice, and 
 there is necessarily bad w^orking of the teeth with the 
 leaves. 
 
2l8 THE MODERN CLOCK. 
 
 We will observe what passes in each of these cases, and 
 refer to the suitable remedies for obtaining a passable 
 depthing and a comparatively good rate, without the neces- 
 sity of repairs at a cost out of all proportion with the value 
 of the article repaired. 
 
 ^ \ \ J ^ ^ ' ^ — ^ '^ i'L A' > / ^"^ 
 
 Fig. 67 
 
 Fig. 6y represents gearing of which the wheel and pinion 
 are well proportioned and at the proper distance from each 
 other. Its movement is smooth, but it has little drop or 
 none at all. By examining the teeth h, h', of the wheel, it 
 is seen that they are larger than the interval between them. 
 With a cutter FF, introduced between the teeth, they are 
 reduced at d, d', which gives the necessary drop without 
 changing the functions, since the pitch circles mm and kk 
 have not been modified. The drop, the play between the 
 tooth d' and the leaf a, is sufficiently increased for the work- 
 ing of the gearing with safety. 
 
 We have the same pair in Fig. 68, but here their pitch 
 circles do not touch ; the depthing is too shallow. The 
 drop is too great and butting is produced between the tooth 
 h and the leaf r, which can be readily felt. The remedy is 
 in changing the center distance, by closing the holes, if 
 
THE MODERN CLOCK. 
 
 219 
 
 worn, or moving one nearer the other. But in an ordinary 
 clock this wheel may be replaced with a larger one, whose 
 pitch circle reaches to e. The proportions of the pair are 
 modified, but not sufficiently to produce inconvenience. 
 
 It may also answer to stretch the wheel, if it is thick 
 enough to be sufficiently increased in size. A cutte*^ should 
 then be selected for rounding up which will allow the full 
 
 
 Fig. 
 
 width to the tooth as at p; but if it is not possible to en- 
 large the wheel enough, a little of the width of the teeth 
 may be taken off, as is seen at h, which will diminish the 
 butting with the leaf r. 
 
 Too great depthing. Fig. 69, can generally be recognized 
 by the lack of drop. When the teeth of the wheel are nar- 
 row, the drop may appear to be sufficient. When the train 
 is put in action the depthing that is too great produces 
 scratching or butting and the 'scape wheel trembles. This 
 results from the fact that the points of the teeth of the 
 wheel touch the core of the pinion and cause it to butt 
 against the leaf following the one engaged, as is visible at 
 r in Fig. 69. It should be noticed that in this figure the 
 pitch circles mm and kk overlap each other, instead of being 
 tangential. 
 
220 
 
 THE MODERN CLOCK 
 
 Fiir. CO 
 
 nc 
 
 ^^ 
 
 Fig. TO 
 
THE MODERN CLOCK. 221 
 
 To correct this gearing, the cutter should act only on the 
 addenda of the teeth of the wheel, so as to diminish them 
 and bring the pitch circle mm to n. The dots in the teeth 
 d, d', show the corrected gearing. It is seen that there will 
 be, after this change, the necessary drop, and that the end 
 of the tooth d' will not touch the leaf r. 
 
 In the two preceding cases we have considered wheels 
 and pinions of accurate proportion, and the defects of the 
 gearing proceeding from the wrong center distances. We 
 will not speak of the gearing in which the pinion is too 
 small. The only theoretic remedy in this case, as in that 
 of too large a pinion, is to replace the defective piece; but 
 in practice, when time and money are to be saved, advan- 
 tage must be taken, one w^ay or another, of what is in 
 existence. 
 
 The buzzing produced when the train runs in a gearing 
 with top small a pinion proceeds from the fact that each 
 tooth has a slight drop before engaging with the corre- 
 sponding leaf. If we examine Fig. 70, it will be easy to 
 see how this drop is produced. The wheel revolving in the 
 direction indicated by the arrow, it can be seen that when 
 the tooth h leaves the leaf r, the following tooth, p, does not 
 engage with the corresponding leaf, s ; this tooth will there- 
 fore have some drop before reaching the leaf. A friction 
 may even be produced at the end or addendum of the tooth 
 p against the following leaf v. 
 
 To obtain a fair depthing without replacing the pinion, 
 the wheels can be passed to the rounding up machine, hav- 
 ing a cutter which will take off only the points of the teeth, 
 as is indicated in the figure ; the result may be observed by 
 the dotted lines. The tooth h being shorter, it will leave 
 the leaf r of the pinion when the latter is in the dotted 
 position; that is to say, a little sooner. At this moment 
 the tooth p is in contact with the leaf s, and there is no risk 
 of friction against the leaf v. Care must be taken to touch 
 only the addendum of the tooth so as not to weaken the 
 
222 
 
 THE MODERN CLOCK. 
 
 teeth. The circumference i will be that of a pinion of ac- 
 curate size, and if the pinion is replaced, it will be necessary 
 to diminish the wheel so that its pitch circle shall be tan- 
 gential with i. 
 
 - With too small a pinion a passable gearing can generally 
 be produced. In any case stoppage can be prevented. This 
 is not so easy when the pinion is too large. In Fig. 71, the 
 
 Fig. 71 
 
 pinion has as its pitch circle the line k, inscead of i, which 
 would be nearer the size with reference to that of the wheel. 
 This is purposely drawn a little small for clearness of illus- 
 tration. The essential defect of such a gearing can be seen ; 
 the butting produced between the tooth p and the leaf s will 
 cause stoppage. How shall this defect be corrected without 
 replacing the pinion? 
 
 To remedy the butting as far as possible, some watch- 
 makers slope the teeth of the wheel by decentering the cut- 
 ter on the rounding-up machine. At FF the cutter is seen 
 working between the teeth d and d'. It is evident that 
 when the wheel becomes smaller it is necessary to stretch it 
 out, and to make use of the cutter afterwards. However, 
 
THE MODERN CLOCK. 
 
 223 
 
 the most rational method is to leave the teeth straight, and 
 to give them the slenderest form possible, after having en- 
 larged the wheel or having replaced it with another. The 
 motive force of the wheel being sufficiently weak, the size 
 of the teeth may be reduced without fear. The essential 
 thing is to suppress the butting. Success will be the easiest 
 when the teeth are thinner. 
 
 In conclusion, we recommend verification of all sus- 
 pected gearings by the depthing tool, which is easier and 
 surer than by the clock itself. One can see better by the 
 tool the working of the teeth with the leaves, and can form 
 a better idea of the defect to be corrected. With the aid of 
 the illustrations that have been given it can be readily 
 noticed whether the depthing is too deep or too shallow, or 
 the pinion too large or too small. 
 
 The defects mentioned are of less consequence in a pinion 
 of seven leaves, and they are corrected more readily. With 
 pinions of higher numbers the depthings will be smoother, 
 provided sufficient care has been taken in the choice of the 
 rounding-up cutters. 
 
 Rounding-Up Wheels. — It is frequently observed that 
 young watchmakers, and (regretfully be it said) some of 
 the older and more experienced ones, are rather careless 
 when fitting wheels on pinions. In many cases the wheel is 
 simply held in the fingers and the hole opened with a broach, 
 and in doing this no special care is taken to keep the fiole 
 truly central and of correct size to fit the pinion snugly, and 
 should it be opened a little too large it is riveted on the 
 pinion whether concentric or not. Many suppose the round- 
 ing-up tool will then make it correct without further trouble 
 and without sufficient thought of the irregularities ensuing 
 when using the tool. 
 
 To make the subject perfectly clear the subjoined but 
 rather exaggerated sketch is shown, Fig. ^2. Of course, it 
 is seldom required to round-up a wheel of twelve teeth, and 
 
224 "^^^ MODERN CLOCK. 
 
 the eccentricity of the wheel would be hardly as great as 
 shown; nevertheless, assuming such a case to occur the 
 drawing will exactly indicate the imperfections arising from 
 the use of a rounding-up tool. 
 
 ' Presuming from the drawing that the wheel, as shown by 
 dotted lines, had originally been cut with its center at m, 
 but through careless fitting had been placed on the pinion at 
 o, and consequently is very much out of round when tested 
 in the calipers, and to correct this defect it is put in the 
 
 7 
 
 
 6 
 
 il '-'': 
 
 rounding-up tool. The cutter commences to remove the 
 metal from tooth y, it being the highest, next the neighbor- 
 mg teeth 6 and 8, then 5 and 9, and so on until tooth i comes 
 in contact with the cutter. The wheel is now round. But 
 how about the size of the teeth and the pitch ? The result of 
 the action of the cutter is shown by the sectionally lined 
 wheel. J\Iany will ask how such a result is possible, as the 
 cutter has acted equally upon all the teeth. Nevertheless, a 
 little study of the action of the rounding-up cutter will soon 
 make it plain why such faults arise. Naturally the spaces 
 between the teeth through the action of the cutter will be 
 equal, but as the cutter is compelled to remove considerable 
 
THE MODERN CLOCK. 22^ 
 
 metal from the point of greatest eccentricity, i. e., at tooth 7 
 and the adjoining teeth, to make the wheel round, and the 
 pitch circle being smaller the teeth become thinner, as the 
 space between the teeth remains the same. At tooth i no 
 metal was removed, consequently it remains in its original 
 condition. The pitch from each side of tooth i becomes less 
 and less to tooth 7, and the teeth thinner, and the thickest 
 tooth is always found opposite the thinnest. 
 
 In the case of a wheel having a large number of teeth and 
 the eccentricity of which is small, such faults as described 
 cannot be readilv seen, from the fact that there are many 
 teeth and the slight change in each is so gradual that the 
 only way to detect the difference is by comparing opposite 
 teeth. And this eccentricity becomes a serious matter when 
 there are but few teeth, as before explained, especially when 
 reducing an escape wheel. The only proper course to 
 pursue is to cement the wheel on a chuck, by putting it in a 
 step chuck or in any suitable manner so that it can be trued 
 by its periphery and then opening the hole truly. This 
 method is followed by all expert workmen. 
 
 A closer examination of the drawing teaches us that an 
 eccentric wheel with pointed teeth — as cycloidal teeth are 
 mostly left in this condition when placed in the rounding-up 
 tool, will not be made round, because when the cutter has 
 just pointed the correct tooth (tooth No. i in the drawing) 
 it will necessarily shorten the thinner teeth, Nos. 6, 7, 8, i. e., 
 the pitch circle v/ill be smaller in diameter. We can, there- 
 fore, understand why the rounding-up tool does not make 
 the wheel round. 
 
 As we have before observed, when rounding-up an eccen- 
 trically riveted wheel, the thickest tooth is always opposite 
 the thinnest, but with a wheel which has been stretched the 
 case is somewhat different. Most wheels when stretched 
 become angular, as the arcs between the arms move outward 
 in a greater or less degree, which can be improved to some 
 extent by carefully hammering the wheel near the arms, but 
 
226 
 
 THE MODERN CLOCK. 
 
 some inequalities will still remain. In stretching a wheel 
 with five arms we therefore have five high and as many de- 
 pressed parts on its periphery. If this wheel is now rounded- 
 up the five high parts will contain thinner teeth than the 
 depressed portions. Notwithstanding that the stretching of 
 wheels, though objectionable, is often unavoidable on ac- 
 count of the low price of repairs, it certainly ought not to be 
 overdone. Before placing the wheel in the rounding-up tool 
 it should be tested in the calipers and the low places care- 
 fully stretched so that the wheel is as nearly round as can be 
 made before the cutter acts upon it. 
 
 It is hardly necessary to mention that the rounding-up tool 
 will not equalize the teeth of a badly cut wheel, and further 
 should there be a burr on some of the teeth which has not 
 been removed, the action of the guide and cutter in entering 
 a space will not move the wheel the same distance at each 
 tooth, thus producing thick and thin teeth. From what has 
 been said it would be wrong to conclude that the rounding- 
 up tool is a useless one ; on the contrary, it is a practical and 
 indispensable tool, but to render good service it must be cor- 
 rectly used. 
 
 In the use of the rounding-up tool the following rules are 
 to be observed : 
 
 1. In a new wheel enlarge the hole after truing the wheel 
 from the outside and stake it concentrically on its pinion. 
 
 2. In a rivetted but untrue wheel, stretch the deeper por- 
 tions until it runs true, then reduce it in the rounding-up 
 tool. The better method is to remove the wheel from its 
 pinion, bush the hole, open concentrically with the outside 
 and rivet, as previously mentioned in a preceding paragraph. 
 But if the old riveting cannot be turned so that it can be used 
 again it is best to turn it entirely away, making the pinion 
 shaft conical towards the pivot, and after having bushed the 
 wheel, drill a hole the proper size and drive it on the pinion. 
 The wheel will be then just as secure as when rivetted, as 
 in doing the latter the wheel is often distorted. With a very 
 
THE MODERN CLOCK. 227 
 
 thin wheel allow the bush to project somewhat, so that it 
 has a secure hold on the pinion shaft and cannot work 
 loose. 
 
 3. Should there be a feather edge on the teeth, this 
 should be removed with a scratch brush before rounding it 
 up, but if for some reason this cannot well be done, then 
 place the wheel upon the rest with the feather edge nearest 
 the latter so that the cutter does not come immediately in 
 contact with it. If the feather edge is only on one side of 
 the tooth — which is often the case — place the wheel in the 
 tool so that the guide will turn it from the opposite side of 
 the tooth ; the guide will now move the wheel the correct dis- 
 tance for the cutter to act uniformly. Of course, in every 
 case the guide, cutter and wheel, .must be in correct position 
 to ensure good work. 
 
 4. To obtain a smooth surface on the face of the teeth 
 a high cutter speed is required, and for this reason it is ad- 
 vantageous to drive the cutter spindle by a foot wheel. 
 
 Making Single Pinions. — There are two ways of mak- 
 ing clock pinions ; one is to take a solid piece of steel of the 
 length and diameter needed and turn away the surplus ma- 
 terial to leave the arbor and the pinion head of suitable di- 
 mensions ; the other way is to make the head and the arbor 
 of separate pieces; the head drilled and fixed on the arbor 
 by friction. The latter plan saves a lot of work, and the cut- 
 ting of the teeth may be easier. One method is as good as 
 the other, as the force on the train is very slight and the 
 pinion head may be driven so tightly on the arbor as to be 
 perfectly safe without any other fastening, provided the 
 arbor is given a very small taper, .001 inch in four inches. 
 The steel for the arbor may be chosen of such a size as to re- 
 quire very little turning, and hardened and tempered to a 
 full or pale blue before commencing turning it, but the piece 
 intended for the pinion head must be thoroughly annealed, 
 or it may be found impossible to cut the teeth without de- 
 
228 THE MODERN CLOCK. 
 
 stroying a cutter, which, being valuable, is worth taking 
 care of. 
 
 Pinions for ordinary work are not hardened; as they are 
 left soft by the manufacturers it would be nonsense for the 
 repairer to put in one hardened pinion in a clock where all 
 the others were soft. Pinions on fine work are hardened. 
 Turning is done between centers to insure truth. 
 
 Before commencing work on the pinion blanks it is ad- 
 visable to try the cutters on brass rod, turned to the exact 
 size, and if the rod is soft enough it will be found that the 
 cutter will make the spaces before it is hardened, which is 
 a very important advantage, admitting of correction in the 
 form of the cutter if required ; only two or three teeth need 
 be cut in the brass to enable one to see if they are suitable, 
 and if foimd so, or after an alteration of the cutter, the en- 
 tire number may be cut round and the brass pinion made use 
 of for testing its accuracy as to size and shape by laying the 
 wheel along with it on a flat plate, having studs placed at 
 the proper center distance. By this means the utmost re- 
 finement may be made in the diameter of the brass pinion, 
 which will then serve as a gauge for the diameter of the 
 steel pinions, it being recollected, as mentioned in a previous 
 paragraph, that a slight variation in the diameter of a pinion 
 may be made to counterbalance a slight deviation from 
 mathematical accuracy in the form of the wheel-teeth, such 
 as is liable to occur owing to the smallness of the teeth mak- 
 ing it impracticable to actually draw the true curves, the 
 only way of getting them being to draw them to an enlarged 
 scale on paper, and copy them on the cutter as truly as pos- 
 sible by the eye. 
 
 Supposing the cutter has been properly shaped, hardened 
 and completed and the steel pinion heads all turned to the 
 diameter of the brass gauge, the cutting may be proceeded 
 with without fear of spoiling, or further loss of time which 
 might be spent in cutting the long pinion leaves; and even 
 what is of more importance in work which does not allow of 
 
THE MODEllN CLOCK. 229 
 
 any imperfection, removing the temptation, which might be 
 strong, to let a pinion go, knowing it to be less perfect than 
 it should be. 
 
 Assuming the pinion teeth to be satisfactorily cut, the next 
 operation will be hardening and tempering. A good way of 
 doing this is to enclose one at a time in a piece of gas pipe, 
 filling up the space around the pinion with something to 
 keep the air off the work and prevent any of the products of 
 combustion attacking the steel and so injuring the surface. 
 Common soap alone answers the purpose very well, or it 
 may have powdered charcoal mixed with it; also the addi- 
 tion of common salt helps to keep the steel clean and white. 
 The heating should be slow, giving time for the pinion and 
 the outside of the tube to both acquire the same heat. Over- 
 heating should be carefully avoided, or there w^ill be scaling 
 of the surfaces, injurious to the steel, and requiring time and 
 labor to polish off. There is no better way of hardening 
 than by dipping the pipe with the pinion enclosed in plain 
 cold water, or if the pinion should drop out of the tube into 
 the water it will do all the same. To be sure the hardening 
 is satisfactory it will be as well not to trust to the clean white 
 color likely to result from this treatment, but try both ends 
 and the center with a file. After all this has been success- 
 fully accomplished the pinions will require tempering, the 
 long arbors straightening, and the teeth polishmg. 
 
 The drilled pinion heads, if hardened at all by the method 
 last mentioned, will, on account of their short lengths, be 
 equally hardened all over, but if the pinion and arbor should 
 be all in one piece care will be needed to ensure equal heat- 
 ing all over, or one part may be burnt and another soft. 
 Also, to guard against bending the long arbors, the packing 
 in the tube will need to be carefully done, so as to produce 
 equal pressure all over ; otherwise, while the steel is red hot, 
 and consequently soft enough to bend, even by its own 
 weight, it may get distorted before dropping in the water. A 
 long thin rod like this almost invariably bends if heated on 
 
230 THE MODERN CLOCK. 
 
 an open fire unless equally supported all along; if hardened 
 so, a little tin tray may be bent up, filled with powdered 
 charcoal, and the pinion bedded evenly in it. Either this way 
 or with a tube the long arbor may get bent before being 
 quenched; but if the arbor, though kept straight up to this 
 point, should happen to be dropped sideways into the water 
 the side cooled first would contract most. To avoid this, 
 the arbor should be dropped endways, as vertically as pos- 
 sible. • 
 
 Tempering the Pinions. — For common cheap work the 
 usual and quickest way is what is called "blazing off." That 
 is done either by dipping each piece singly in thick oil and 
 setting the oil on fire, allowing it to burn away, or placing 
 a number of pieces in a suitably sized pan, covering with 
 oil, and burning it. The result is the same either way, the 
 method being simply a matter of convenience regulated 
 by the number of pieces to be tempered at one time. As 
 the result of blazing off is to some extent uncertain, and 
 the pinions apt to be too soft, it will be advisable to ndopt 
 the process of bluing, by which the temper desired may be 
 produced with more accuracy. The first thing to do will 
 be to clean the suriace of the arbor all along on one side ; 
 the pinion head may be left alone. As the pinion head 
 would get overheated before the arbor had reached the blue 
 color, if the piece were simply placed on a bluing pan or 
 a lump of hot iron, it will be necessary to provide a layer 
 of som€ soft substance to bed the pinion on ; iron, steel or 
 brass filings answer well because the heat is soon uniformly 
 distributed through the mass, and by judiciously moving the 
 lamp an equable temper may be got all along, as deter- 
 mined by the color. There is another and very sure way 
 of getting a uniform temper, in using which there is no 
 need to polish the arbors. The heat of lead at the point of 
 fusion happens to be just about the same as that required 
 for the tempering of this work; so if a ladle full of lead 
 
THE MODERN CLOCKc 231 
 
 is available each pinion may be buried in it for a few sec- 
 onds, holding it down beneath the molten surface with hot 
 pHers. The temper suitable is indicated by a pale blue, a 
 little softer than for springs, and a piece of poHshed steel 
 set floating on the lead will indicate whether the heat is 
 suitable; if found too great some tin may be added, which 
 will cause the metal to melt at a lower temperature. Over- 
 heating the metal must be avoided: it should go no higher 
 than the bare melting point. 
 
 Straightening Bent Arbors. — When. all care has been 
 taken in the hardening, the long pieces of wire are still 
 apt to become bent more or less, and this is especially the 
 case with solid pinions ; so before proceeding further the 
 pieces must be got true, or as nearly so as possible, and it 
 will be found impracticable to do this by simple bending 
 when the steel is tempered. If the piece is placed between 
 centers in the lathe and rotated slowly, the hollow side will 
 be found; this side must be kept uppermost while the steel 
 is held on a smooth anvil, and the pene, or chisel-shaped, 
 end of a small hammer applied crossways with gentle 
 blows, stepping evenly along so that each portion of the 
 steel is struck all along the part which is hollow ; this will 
 stretch the hollow side, and, by careful working, trying the 
 truth from time to time, the piece can be got as true as may 
 be wished, and probably keep so during the subsequent turn- 
 ing and finishing, though it is advisable to keep watch on it, 
 and if it shows any tendency to spring out of truth again, 
 repeat the striking process, which should always be done 
 gently and in such a way as to show no hammer marks. 
 Having got the pieces suf^ciently true in this way, each 
 arbor may have a collet of suitable size driven on to it for 
 permanency, and as the collets will probably be a little out 
 of truth they may have a finishing cut taken all over them 
 and receive a final polish. 
 
232 THE MODERN CLOCK. 
 
 Polishing. — To polish the steel arbors after turning, a 
 flat metal polisher, iron or steel, is used; this with emery 
 or oilstone dust and oil produces a true surface, with a 
 sharp corner at the shoulder; the polisher will require fre- 
 quent filing on the flat and the edge to keep it in shape 
 with a sharp corner, and a grain crossing like the cuts on 
 a file to hold the grinding material. The polishing of ar- 
 bors is not done with the object of making them shine, but 
 to get them smooth and true, so there is no need of using 
 any finer stuff than emery or oilstone dust. 
 
 An old way to polish the leaves was to use a simple 
 metal polisher of a suitable thickness, placing the pinion on 
 a cork or piece of wood, or even holding it in the fingers ; 
 working away at a tooth at a time until a good enough pol- 
 ish was obtained; but this method, while being satisfactory 
 as to results, was also tedious and very slow. 4t was in 
 some cases assisted by having guide pinions fitted tight on 
 one or both ends of the arbors to prevent rounding of the 
 teeth, the polisher resting in the guide and the tooth to be 
 polished. On the American lathes an accessory is provided 
 called a "wig wag." This is a rod fastened at one end to a 
 pulley by a crank pin near its circumference ; the pulley 
 being rotated by a belt from the counter shaft pulleys 
 causes the rod to move rapidly backwards and forwards. 
 On the other end of the rod a long narrow piece of lead 
 or tin is fixed, the pinion being fitted by its centres into a 
 simple frame held in the slide rest so that it can be rotated 
 tooth by tooth; the lead soon gets cut to the form of the 
 teeth, and the polishing is quickly effected. Another way 
 is to take soft pine or basswood, shape it roughly to about 
 the form of space between two teeth and use it as a file, 
 with emery and oil or oilstone dust. The wood is soon cut 
 to the exact shape of the teeth, and then makes a quick and 
 perfect job. The pinion is held in the jaws of the vise and 
 the wooden polisher used as a file with both hands. 
 
THE MODERN CLOCK. 
 
 233 
 
 Where there is much polishing to do a simple tool, 
 which a workman can form for himself, produces a result 
 which is all that can be desired. It consists of an arbor 
 to work between the lathe centres, or a screw chuck for 
 wood, with a round block of soft wood, of a good diameter, 
 fixed on it, and turned true and square across ; this will get 
 a spiral groove cut in it by the corners of the pinion leaves. 
 The pinion is set between centres in a holder in the slide 
 rest, with the holder set at a slight angle, so that, instead of 
 circular grooves being cut in the wood a screw will be 
 formed, the angle being found by trial. On the wood block 
 being rotated and supplied with fine emery the pinion will 
 be found to rotate, and, being drawn backwards and for- 
 wards by the slide rest, can be polished straight, while the 
 circular action of the polisher will cause the sides of the 
 pinion leaves to be made quite smooth and entirely free 
 from ridges. 
 
 If it should be desired to face the pinions, like watch 
 pinions, it may be done in the same way, by cutting hollows 
 so as to leave only a fine ring round the bottoms of the 
 teeth, and using a hollow polisher with a flat end held in the 
 fingers while the pinion is rotating. A common cartridge 
 shell with a hole larger than the arbor drilled in the center 
 of the head makes a fine polisher for square facing on the 
 ends of pinions, while a stick of soft wood will readily adapt 
 itself to moulded ends. 
 
 The pinion heads being finished and got quite true, the 
 arbors may be turned true and polished. It is not advisable 
 to turn the arbors small ; they will be better left thick so as 
 to be stiff and solid, as the weight so near the center is of 
 no importance, the velocity on the small circumference in 
 starting and stopping being also inappreciable. The thick- 
 ness of the arbors when the pinion heads are drilled is de- 
 termined by the necessity of having sufficient body inside 
 the bottoms of the teeth ; but when solid they may with ad- 
 vantage be left thicker; however, there is no absolute size. 
 
234 
 
 THE MODERN CLOCK. 
 
 The ends on which the collets for holding the wheels are to 
 be fixed may be turned to the same taper as the broach 
 which will be used for opening the collet holes, while the 
 other ends may be straight. 
 
 'None of the wheels in a fine clock should be riveted 
 to the pinion heads ; even the center wheel, which goes quite 
 up to the pinion head, is generally fixed on a collet. The 
 collets are made from brass cut off a round rod, the outside 
 diameters being just inside the edges of the wheel hubs, 
 and a shoulder turned to fit accurately into the center hole 
 of each wheel. These collets should first have their holes 
 broached to fit their arbors, allowing a little for driving on, 
 as they may be made tight enough in this way without sol- 
 dering. Be careful to keep the broach oiled to prevent 
 sticking if you want a smooth round hole. 
 
 The holes in the wheels being made, each collet may be 
 turned to a little over its final size all over, and then driven 
 on to its place on the pinion, so that a final turning may be 
 made to ensure exact truth from the arbors' own centers. 
 When the collets are thus finished in their places .on the ar- 
 bors, and the wheels fitted to them, if it is a fine clock, such 
 as a regulator, a hole may be drilled through each wheel 
 and its collet to take a screw, the holes in the collet tapped, 
 the holes in the wheels enlarged to allow the screw to pass 
 freely through, and a countersink made to each, so that the 
 screws, when finished, may be flush with the wheels. One 
 hole having been thus made and the wheel fixed with a 
 screw, the other two holes can be made so as to be true, 
 which would not be so well accomplished if all the holes 
 were attempted at once. The spacing of the three screws 
 will be accurate enough if the wheel arms be taken as a 
 guide. If all this has been correctly done, the wheels will 
 go to their places quite true, both in the round and the flat, 
 and may be taken off for polishing, and replaced true with 
 certainty, any number of times. 
 
THE MODERN CLOCK. 235 
 
 The polishing of the pivots should be as fine as possible ; 
 all should be well burnished, to harden them and make them 
 as smooth as possible if it is a common job; if a fine one 
 with hardened arbors the pivots may be ground and pol- 
 ished as in watch work ; if the workman has a pivot polisher 
 and some thin square edged laps this is a short job and 
 should be done before cutting off the centers and rounding 
 the ends of the pivots. During all this work the wheels, 
 as a matter of course, will be removed from the pinions, and 
 m.ay now be again temporarily screwed on, the polishing of 
 them being deferred till the last, as otherwise they would 
 be liable to be scratched. 
 
 Lantern Pinions. — The lantern pinion is little under- 
 stood outside of clock factories and hence it is generally 
 underrated, especially by watchmakers and those working 
 generally in the finer branches of mechanics. It will never 
 be displaced in clock work, however, on account of the fol- 
 lowing specific advantages : 
 
 I. It offers the greatest possible freedom from stoppage 
 owing to dirt getting into the pinions, as if a piece large 
 enough to jam and stop a clock with cut pinions, gets into 
 the lantern pinion, it will either fall through at once or be 
 pushed thiough between the rounds of the pinion by the 
 tooth of the wheel and hence will not interfere with its 
 operation. It is therefore excellently adapted to run under 
 adverse circumstances, such as the majority of common 
 clocks are subjected to. 
 
 2. Without giving the reasons it is demonstrable that as 
 smooth a motion may be got by a lantern pinion as by a 
 solid radial pinion of twice the number, and that the force 
 required to overcome the friction of the lantern is therefore 
 much less than with the other. It follows that such pinions 
 can be used with advantage in the construction of all cheap 
 and roughly constructed clocks which are daily turned out 
 in thousands to sell at a low price. 
 
236 THE MODERN CLOCK. 
 
 3. We have before pointed out the enormous advantages 
 of small savings per movement in clock factories which are 
 turning out an annual product of millions of clocks, and 
 without going into details, it is sufficient to refer to the 
 fact that where eight or ten millions of clocks are to be 
 made annually the difference in the cost of keeping up the 
 drills and other tools for lantern pinions over the cost of 
 similar work on the cutters for solid pinions is sufficient 
 to have a marked influence upon the cost of the goods. 
 Then the rapidity with which they can be made and the 
 consequent smallness of the plant as compared with that 
 which must be provided for turning out an equal number of 
 cut pinions is also a factor. There are other features, but 
 the above will be sufficient to show that it is unlikely that 
 the lantern pinion will ever be displaced in the majority of 
 common clocks. From seventy-five to ninety per cent of 
 the clocks now made have lantern pinions. 
 
 The main difference between lantern and cut pinions 
 mechanically is that as there is no radial flank for the curve 
 of the wheel tooth to press against in the lantern pinion 
 the driving is all done on or after the line of centers, except 
 in the smaller numbers, and hence the engaging or butting 
 friction is entirely eliminated when the pinion is driven, 
 as is always the case in clock work. Where the pinion is 
 the driver, however, this condition is reversed and the driv- 
 ing is all before the line of centers, so that it makes a very 
 bad driver and this is the reason why it is never used as a 
 driving pinion. This, of course, bars it from use in a large 
 class of machinery. 
 
 The actual making of lantern pinions will be found to 
 offer no difficulties to those who possess a lathe with divid- 
 ing arrangements, a slide rest, and a drill holder or pivot 
 polisher to be fixed on it. The pitch circle, being through 
 the centers of the pins, can be got with great accuracy by 
 setting the drill point first to the center of the lathe, read- 
 ing the division on the graduated head of the slide rest 
 
THE MODERN CLOCK. 237 
 
 screw, and moving the drill point outwards to the exact 
 amount of the semi-diameter of the pitch circle. This pre- 
 supposes the slide rest screw being cut to a definite standard, 
 as the inch or the meter, and all measurements of wheels' 
 and pinions being worked out to the same standard, the 
 choice of the standard being immaterial. If the slide rest 
 screw is not standardized the pitch circle may be traced 
 with a graver and the drill set to center on the line so 
 traced. 
 
 The heads of the pinions may be made either of two 
 separate discs, each drilled separately, and carefully fitted 
 on the arbor so that the pins may be exactly parallel with 
 the arbor; or, of one solid piece bored through the center, 
 turned down deep enough in the middle, and the drill sent 
 right through the pin holes for both sides at one operation. 
 The former way will be necessary when the number of pins 
 is small, but the latter is better when the numbers are large 
 enough to allow of considerable body in the center. In 
 either case it is advisable to drill only part way through one 
 shroud and to close the holes in the other with a thin brass 
 washer pressed on the arbor and turned up to look like part 
 of the shroud after the pins are fitted in the holes. This 
 makes a much neater way of closing the holes than riveting 
 and takes but a moment where only one or two pinions are 
 being made. 
 
 There is no essential proportion for the thickness of the 
 pins or rounds. In mathematical investigations these are 
 always taken at first as mere points of no thickness at all; 
 then the diameters are increased to w^orkable proportions, 
 and the width of the wheel-tooth correspondingly reduced 
 until there is a freedom or a little shake. If much power 
 has to be transmitted, the pins, or ''staves," as they are 
 called in large work, have to be strong enough to stand the 
 strain, but, as the strain in clockwork is very small, the pins 
 need not be nearly as thick as the breadth of a wheel-tooth. 
 In modern factory practice the custom is to have the diam- 
 
238 THE MODERN CLOCK. 
 
 eter of the rounds equal to the thickness of the leaf of a cut 
 pinion of similar size, the measurement being taken at the 
 pitch circle of the cut pinion. As we have already given 
 the proportions observed in good practice on cut pinions 
 they need not be repeated here. Another practice is to have 
 wheel teeth and spaces equal ; when this is done the spacing 
 of all pinions above six leaf is to have the rounds occupy 
 three parts and the space five parts. 
 
 In some old church clocks, lantern pinions were much 
 used, in many cases with the pins pivoted and working 
 freely in the ends, or, as they called them, "shrouds," but 
 this was a mistake, and they are never made so now. A 
 simple way for clock repair work is to get some of the 
 tempered steel drill rod of exactly the thickness desired, 
 hold one end by a split chuck in the lathe, let the other end 
 run free, and polish with a bit of fine emery paper clipped 
 round it with the fingers, when the wire will be ready for 
 driving through the pinion heads, the holes being made 
 small enough to provide for the rounds being firmly held. 
 The drill may be made of the same wire. The shrouds 
 may be made either of brass or steel ; the latter need not be 
 hardened, and, when the rounds are all in place and cut ofif, 
 the ends may be polished as desired. In the case of a cen- 
 ter wheel, where the pinion is close up to the wheel, and 
 space cannot be spared, the collet on which the wheel is 
 mounted may form one end of the pinion head. 
 
 The Wheel Teeth. — The same principles of calculation 
 belong to these and solid-cut pinions, the only difference 
 being that the round pins require wheel teeth of a different 
 shape from those suited to pinion leaves with radial sides. 
 Both are derived from epicycloidal curves ; the curve used 
 for lantern pinions is derived from a circle of the same size 
 as the pitch circle of the pinion, while the curve for wheel 
 teeth to drive radial-sided leaves is derived from a circle of 
 half that diameter, so that the wheel teeth in the former 
 
THE MODERN CLOCK. 
 
 239 
 
 Fig. 73. Lantern pinion showing pitch circle. 
 
 Fig. 74. Generating epicycloid curve for lantern pinion above ; com- 
 pare with curve for cut pinion of same size pitch circle, page 206. 
 
240 THE MODERN CLOCK. 
 
 are more pointed than in the latter. There also is a farther 
 difference; as was explained in detail when treating of cut 
 pinions, the curve of the wheel tooth presses upon the radial 
 flank of the leaf inside its pitch circle. Now there is no 
 radial flank in the lantern and the curve is generated from 
 a circle of twice the diameter, so that it is twice as long — 
 long enough to interfere — so it is cut off (rounded) just 
 beyond the useful portion of the working curve of the wheel 
 tooth. 
 
 Pillars and arbors are simple parts, yet much costly ma- 
 chinery is used in making them. The wire from which 
 they are made is brought tothe factories in large coils, and 
 is straightened and cut into lengths by machines. The 
 principle on which wire is straightened in a machine is 
 exactly the same as. a slightly curved piece of wire is made 
 straight in the lathe by holding the side of a turning tool 
 between the revolving wire and the lathe rest, which is an 
 operation most of our readers must have practiced. The 
 rapid revolution of the wire against the turning tool causes 
 its highest side to yield, till finally it presses on the turning 
 tool equally all round, and is consequently straight. How- 
 ever, in straightening wire by machines the wire is not 
 made to revolve, but remains stationary while the straight- 
 ening apparatus revolves around it. Wire-straightening ma- 
 chines are usually made in the form of a hollow cylinder, 
 having arms projecting from the inside towards the center. 
 The cylinder is open at both ends, and the arms are ad- 
 justable to suit the different thicknesses of wire. The wire 
 is passed through the ends of the cylinder, and comes in 
 contact with the arms inside. A rapid rotary motion is 
 then given to the cylinder, which straightens the wire in 
 the most perfect manner, as it is drawn through, without 
 leaving any marks on it when the machine is properly ad- 
 justed. The long spiral lines that are sometimes seen on 
 the w^ire w^ork of clocks is caused by this w^ant of adjust- 
 ment; and they are produced in the same way as broad 
 
THE MODERN CLOCK. 
 
 241 
 
 circular marks would be made in soft iron wire if the side 
 of the turning tool was held too hard against it when 
 straightening it in the lathe. 
 
 After the wire has been straightened it is cut off into 
 the required lengths, and this operation is worthy of notice. 
 If the thick sizes of wire that are used were to be cut by 
 the aid of a file or a chisel, the ends would not be square, 
 and some time and material would be lost in the operation 
 
 Fig. 75. A Slide Gauge Lathe. 
 
 of squaring them; and as economy of material as well as 
 economy of labor is a feature in American clock manufac- 
 ture, wire of all sizes is sheared or broken off into lengths, 
 by being fed through round holes in the shears, which act 
 the same as when a steady pin is broken when a cock or 
 bridge gets a sudden blow on the side, or in the same man- 
 ner as patent cutting plyers work. The wire is not bent in 
 the operation, and both ends of it are smooth and flat. The 
 wire for the pillars is then taken to a machine to have the 
 points made and the shoulders formed for the frames to rest 
 against. This machine is constructed like a machinist's 
 bench lathe, with two headstocks. There is a live spindle 
 running in both heads. In the ends of these spindles, that 
 point towards the center of the lathe, cutters are fastened, 
 and the one is shaped so that it will form the end and shoul- 
 
242 THE MODERN CLOCK. 
 
 der of the pillar that is to be riveted, while the other is 
 shaped so as to form the shoulder and point that is to be 
 pinned. Between these two revolving cutters there is an 
 arrangement, worked by a screw in the end of a handle, for 
 holding the wire from which the pillar is to be made, in a 
 firm and suitable position. The cutters are then made to 
 act simultaneously on the ends of the wire by a lever acting 
 on the spindles, and the points and shoulders are in this 
 way formed in a very rapid manner, all of the same length 
 and diameter. These machines are in some points auto- 
 matic. The pieces of wire are arranged in quantities in a 
 long narrow feed box that inclines towards the lathe, and 
 the mechanism for holding the wire is so arranged that 
 when its hold is loosened on the newly made pillar, the 
 pillar drops out into a box beneath, and a fresh piece of 
 wire drops in and occupies its place. 
 
 In many of the factories, some clocks are manufactured 
 having screws in place of pins to keep the frames together, 
 and the pillars of these clocks are made in a different man- 
 ner than that we have just described. The wire that is used 
 is not cut into short lengths, but a turret lathe with a hol- 
 low spindle is used, through which the wire passes, and is 
 held by a chuck, when a little more than just the length 
 that is necessary to make the pillar projects through the 
 chuck. The revolving turret head of the lathe has cutting 
 tools projecting from it at several points. One tool is 
 adapted to bore the hole for the screw, and when it is bored 
 the next tool taps the hole to receive the screw, while an- 
 other forms the point and shoulder ; and after that end of 
 the pillar is comipleted another tool attached to the slide 
 of the lathe forms the other shoulder, prepares that end for 
 riveting, and cuts it off at the same time. One thousand 
 of these pillars are in this manner made in a day on each 
 machine. The screws that screw into them are made on 
 automatic screw machines. The latest improvements .in this 
 direction being to first turn the blanks and then roll the 
 threads on thread rolling machines. 
 
THE MODERN CLOCK. 243 
 
 The pinion arbors, after they have been cut to length, are 
 centered on one end by a milling machine having a conical 
 cutter made for the purpose. The collets for the pinion 
 heads, and the one to fasten the wheel by, are punched out 
 of sheet brass, and a hole is drilled in their centers a little 
 smaller than the wire ; and to drive them on, in most in- 
 
 Fig. 76. Slide Gauge Tools and Rack. 
 
 stances, is all that is necessary to hold them. At one time 
 it was the practice to drive these collets by hand. One was 
 placed on the point of the arbor, and the point was then 
 placed over a piece of steel, with a series of holes in it 
 of such depths that the collets would be in their proper 
 position on the arbor when the point was driven to the 
 bottom of the hole, but this method has now been super- 
 seded by automatic machinery, which will be described 
 
244 '1'^^ MODERN CLOCK, 
 
 later. It is impossible to give an intelligible description of 
 these machines without drawings. All we can say at 
 present is that they perform their work in a very rapid and 
 effective manner, and are in use by all the larger clock fac- 
 tories. 
 
 The barrels of weight clocks are mostly made from 
 brass castings, and slight projections are raised on the sur- 
 face of their arbors by swedging, so as to prevent the 
 arbors from getting loose in the barrels after repeated wind- 
 ing of the clock. This swedging and all the other opera- 
 tions in making arbors used to be done on separate ma- 
 chines; but the largest companies now use a powerful and 
 comprehensive machine that works automatically, and 
 straightens any size of wire necessary to be used in a clock, 
 cuts it to the length, centers it, and also swedges the pro- 
 jections on the barrel arbors, or any of the other arbors 
 that may be necessary. A roll of wire is placed on a reel 
 at one end of the machine, first passing through a straight- 
 ening apparatus, and afterwards to that portion of the ma- 
 chine where the cutting, swedging and centering are exe- 
 cuted, and the finished arbors drop into a box placed ready 
 to receive them. The saving effected by the use of this 
 machine is very great, and in some instances amounts to a 
 thousand per cent over the method of straightening, cutting, 
 swedging and centering on different machines, at different 
 operations. 
 
 Boring the holes in the arbors of the locking work, to 
 receive the smaller wires, and the pin holes in the points 
 of the pillars, is done by small twist drills, run by small 
 vertical drill presses. The work is held in adjustable frames 
 under the drill, and when more than one hole has to be 
 bored this frame is moved backward or forward between 
 horizontal slides to the desired distance, which is regulated 
 by an adjustable stop, so that every hole in each piece is 
 exactly in the same position. In arbors where holes have 
 to be bored at right angles to each ether, the arbor is turned 
 
THE MODERN CLOCK. 
 
 245 
 
 round to the desired position by means of an index. The 
 holes in the locking work arbors are bored just the size 
 to fit the wire that is to go into them, and these small 
 
 
 
 1 ' **i3l^. "" 
 
 
 ^i 
 
 4 
 
 ttiJIi- 
 
 
 
 i^fed 
 
 "^rm 
 
 
 
 
 mt H" 
 
 ^ ' 
 
 
 f 
 
 i 
 
 ^^~^^, ,i|^^- 
 
 
 1 
 
 1 
 
 i 
 
 
 lUiH" 
 
 fi mk» 
 
 1 
 
 ^Jb 
 
 H^^HL„ ^r ^£ ~ '^^^H 
 
 f 
 
 Fig. 77. Automatic Pinion Making Machine of the Davenport Machine 
 
 Company. 
 
 wires are easily and rapidly fastened in place by holding 
 them in a clamp made for the purpose, and riveting them 
 either with a hammer or with a hammer and punch. 
 
246 THE MODERN CLOCK. 
 
 The Slide Gauge Lathe — The system of turnin;^^ with 
 the sUde gauge lathe, formerly adopted for lantern pinions 
 in the clock factories, would seem to the watchmaker of a 
 peculiarly novel nature. The turning tools are not held in 
 the hand, in the manner generally practiced, neither are 
 they held in the ordinary sHde rest, but are used by a com- 
 bination of both methods, which secures the steadiness of 
 the one plan and the rapidity of the other. Adjustable 
 knees are fastened to the head and tail stocks of the lathCj 
 Figs. 75 and 76, which answer the purpose of a rest ; both 
 the perpendicular and horizontal parts of these knees being 
 fastened perfectly parallel with the centers of the lathe. 
 A straight, round piece of iron, of equal thickness, and 
 having a few inches in the center of a square shape, mor- 
 tised for the reception of cutters, is laid on these knees, 
 and answers the purpose of a handle to hold the cutting 
 tools. Two handles will thus hold eight tools, one set for 
 brass and one for steel. On every side of the square part 
 of this iron bar, or what we will now call the turning tool 
 handle, a number of cutting tools are fastened by set screws, 
 and the method of using them is as follows : The operator 
 holds the tool handle with both hands on to the knees that 
 are fastened to the head and tail stocks of the lathe, with 
 the turning tool that is desired to be used pointing towards 
 the center, and it is allowed to come in contact with the 
 work running in the lathe in the usual manner practiced in 
 turning. Fig. 76 is from a photo furnished by Mr. H. E. 
 Smith of the Smith Novelty Co., Hopewell, N. J., and 
 shows the tools in the rack, w^hich is wound with leather 
 so that the tools may be rapidly thrown in place without 
 injury. 
 
 If a plain, straight piece of work is to be turned, the 
 tool is adjusted in the handle so that the work will be of 
 the proper diameter when the round parts of the handle 
 come in contact with the perpendicular part of the knees 
 or rest; and while the handle is thus held and moved gently 
 
THE MODERN CI.OCK. 
 
 247 
 
 ^]]I3 Stock advanced. 
 
 V 
 
 p 
 
 First collet driven. 
 
 Second collet driven. 
 
 Third collet driven. 
 
 n 
 
 Ri 
 
 Shoulder turned. 
 
 First sides faced. 
 
 Second sides faced. 
 
 fO 
 
 Pivots turned. 
 
 ^]=n=I 
 
 Pivots burnished. 
 
 Cut oft. 
 
 Fig. 78. 
 
 Showing Successive Steps in Turning on Automatic Pinion 
 Making Machine. 
 
248 THE MODERN CLOCK. 
 
 along in the corners of the knees, with the tool sliding on 
 the T-rest, the work is easily turned perfectly parallel, 
 smooth and true. Sometimes a roughing cut is taken by 
 holding the bar loosely and then a finishing cut is made 
 with the same tool by holding it firmly in place. In turning 
 a pinion arbor, for instance, the wire having been previously 
 straightened and cut to length and centered, and the brass 
 collets to make the pinion and to fasten the wheel having 
 l)een driven on, one end is held in the lathe by a spring 
 chuck fastened to the spindle of the lathe, while the other 
 end works in a center in the other head. One turning tool 
 is shaped and adjusted in the handle for the purpose of 
 turning the brass collets for the pinion to the proper diam- 
 eter, another turns the sides of the brass work, while others 
 are adapted for the arbors, pivots, and so on, pins being 
 placed in holes in the T-rest to act as stops for the tools. 
 After the brass work has been turned, the positions of the 
 shoulders of the pivots are marked with a steel gauge, and 
 by simply turning round the handle of the turning tool till 
 the proper shaped point presents itself, each operation is 
 accomplished rapidly, and the cutting is so smooth that 
 even for the pivots all that is necessary to finish them is 
 simply to bring them in contact with a small burnisher. 
 The article is not taken from the lathe during the whole 
 process of turning, and when completed the centers are 
 broken off, having been previously marked pretty deep at 
 the proper place wi'th a cutting point. Five hundred to 
 1,200 arbors per day, per man, is the usual output. All 
 the pinions, arbors, and barrels — in fact every part of an 
 American clock movement that requires turning — were for- 
 merly done in this manner, at long rows of lathes in rooms, 
 and by workmen set apart for the purpose. But perhaps it 
 may be well to mention that in the machine shops of these 
 factories, where they make the tools, the ordinary methods 
 of turning with the common hand tool, and by the aid of 
 ordinary and special slide rests, are practiced the same as it 
 
THE MODERN CLOCK. 
 
 '49 
 
 No. 79. Automatic Pinion Drill of the Davenport Machine Company. 
 
250 THE MODERN CLOCK. 
 
 is among other machinists. In the large factories automatic 
 turret machines are now coming into use and these are 
 shown in Figs., 77, 78 and 79. 
 
 The lantern pinions of an American clock have long been 
 a mystery to those unacquainted with the method of their 
 manufacture, and the usual accuracy in the position of the 
 small wires or "rounds/' combined with great cheapness, 
 has often been a subject of remark. The holes for the 
 wires in these pinions are drilled in a machine constructed 
 as follows: An iron bed with two heads on it, Fig. 80, one 
 of which is so constructed that by pulling a lever the spin- 
 dle has a motion lengthwise as well as the usual circular 
 motion, and on the point of this spindle, which is driven at 
 22,000 revolutions, the drill is fastened that is to bore tne 
 holes in the pinions ; the other head has an arbor passing 
 through it with an index plate attached, having holes in the 
 plate, and an index finger attached to a strong spring going 
 into the holes, the same as in a wheel-cutting engine; on 
 this head, and on the end of it that faces the drill, there is 
 a frame fastened in which the pinion that is to be bored 
 is placed between centers, and is carried round with the 
 arbor of the index plate,, in the same manner as a piece of 
 work is carried round in an ordinary lathe by means of a 
 dog, or carrier; only in the pinion drilling machine the 
 carrier is so constructed that there is no shake in any way 
 between the pinion and the index arbor. This head is car- 
 ried on a slide having a motion at right angles to the spindle 
 of the other head, by w^iich means the pitch diameter of 
 the proposed pinion is adjusted. The head is moved in the 
 slide by an accurately cut screw, to which a micrometer is 
 attached that enables the workman to make an alteration 
 in the diameter of a pinion as small as the one-thousandth 
 part of an inch. The drill that bores the holes is the ordi- 
 nary flat-pointed drill, and has a shoulder on its stem that 
 stops the progress of the drill when it has gone through 
 the first part of the pinion head and nearly through the 
 
THE MODERN CLOCK. 
 
 251 
 
 other. All operators make their own drills and the limits 
 of error are for pitch diameter .0005 inch; error of size of 
 drills .0001. The reader can see that these men must know 
 something of drill making. 
 
 The action of the machine is simple. The pinion, after 
 it has been turned, pivoted and dogged, is placed in its 
 
 Fig. 80. Pinion Drilling Machine. 
 
 position in the machine, and by pulling a lever, the drill, 
 which is running at a speed of about 22,000 revolutions a 
 minute, comes in contact with the brass heads of the pinion 
 and bores the one through and the other nearly through. 
 The lever is then let go, and a spring pulls the drill back ; 
 the index is turned round a hole, and another hole bored in 
 the pinion, and so on till all the holes are bored. An ordi- 
 nary expert workman, with a good machine, will bore 
 about fourteen hundred of medium-sized pinions in a day. 
 
25^ 
 
 THE MODERN CLOCK. 
 
 The wires or ''rounds" are cut from drill rod and are put 
 into the holes by hand by girls who become very expert at 
 it. This is called "filling." We have already stated that 
 the holes are only bored partly through one of the pieces 
 of the brass, and after the wire has been put in, the holes 
 are riveted over, and in this manner the wires are fastened 
 so that they cannot come out. Some factories close the 
 holes by a thin brass washer forced on the arbor, instead of 
 riveting. 
 
 Figs, "j^j, 78 and 79 show the automatic pinion turning 
 machine and its processes in successive operations. These 
 machines are used by most of the large clock manufacturers 
 of the United States and some of the European concerns 
 also. They are entirely automatic, will make 1,500 pinions 
 per day, as an average, and one man can run four ma- 
 chines. 
 
 Fig. 79 shows an automatic pinion drilling machine, 
 which takes up the work where it is left by the' machine 
 shown in Fig. ']']. This machine will drill 4,000 to 5,000 
 pinions per day according to the size hole and the number 
 of holes. The operator places the pinions in the special 
 chain shown in the front of the machine, from which the 
 transport arms ca^*-y them to the spindle, where they are 
 drilled and when completed drop out. One operator can 
 feed three of these machines. 
 
 Making Solid Pinions. — The solid steel pinions are not 
 hardened, but are made of Bessemer steel, which could only 
 be case hardened — a thing hardly ever done. The process 
 of making these pinions is as follows : Rods of Bessemer 
 steel are cut into suitable lengths. The pieces obtained are 
 pointed or centered on both ends. The stock not needed for 
 the pinion head is cut away, leaving the arbors slightly 
 tapering, for the purpose of fastening them by this means 
 in a hole on the cutting machine. On the end of the arbor 
 of the index plate are two deep cuts across its center, and 
 
THE MODERN CLOCK. 253 
 
 at right angles to each other. These cuts are of the same 
 shape that would be made by a knife-edged file. The effect 
 of these cuts is to produce a taper hole in the end of the 
 arbor, with four sharp corners. Into this hole the end of 
 the arbor of the pinion or ratchet that is to be cut is placed, 
 and a spring center presses on the other end, and the sharp 
 corners in the hole hold the work firm enough to prevent it 
 from turning round when the teeth are being cut. The 
 marks that are to be seen on the shoulder of the back pivot 
 of the arbor that carries the minute hand of a Yankee clock 
 is an illustration of this method of holding the pinion when 
 the leaves are being cut, and no injurious effects arise from 
 it. The convenience the plan affords for fastening work in 
 the engine enables twenty-five hundred of these pinions to 
 be cut in a day, one at a time. The pinion head is cut sub- 
 ject to the proper dividing plate by a splitting circular saw, 
 and by a milling tool (running in oil) for forming the shape 
 of the leaves, both of which tools are generally carried on 
 the same arbor, both being shifted into their proper places 
 by an adjusting attachment. Pinion leaves of the better 
 class are generally shaped by two succeeding milling cut- 
 ters, the second one of which does the finishing, obviating 
 any other smoothing. For very cheap work the arbors re- 
 ceive no further finish. The shaping of the pivots, done by 
 an automatic lathe, finishes the job. 
 
 Figure 8i shows an automatic pinion cutting machine 
 which has extensive use in clock factories for cutting pinions 
 up to one-half inch diameter and also the smaller wheels. 
 For wheels the work is handled in stacks suited to the tra- 
 verse of the machine, the work being treated as if the stacks 
 were long brass pinions. 
 
 Wheels are cut in two ways, on automatic wheel cutters 
 as just described and on engines containing parallel spindles 
 for the cutters, carried in a yoke which rises and falls, so 
 that it clears the work while the carriage is returning to 
 the starting point on each trip and engages it on the out- 
 
254 
 
 THE MODERN CLOCK. 
 
 ward trip. The cutters are about three inches in diameter 
 and rapidly driven; the first is a saw, the second a roughing 
 cutter, and the third a finishing cutter. The carriage is 
 
 Fig. 81. Automatic Wheel and Pinion Cutters. 
 
 driven by a rack and pinion operated by a crank in the 
 hands of the workman and streams of soda water are used 
 on the cutters and work to carry away the heat, as brass 
 expands rapidly under heat, and if the stack were cut dry 
 
THE MODERN CLOCK. 
 
 255 
 
 the cut would get deeper as the cutting proceeded, owing 
 to the expansion of the brass, and hence the finished wheel 
 would not be round when cold, if many teeth were being 
 cut. The stacks of wheels are about four inches in 
 length and the slide thus travels about twenty inches in 
 
 Fig. 82. Wheel Cutting Engine. 
 
 order to clear the three arbors and engage with the shifter 
 for the index. The last wheel of the stack has a very large 
 burr formed by the cutters as they leave the brass and this 
 wheel is removed from the stack when the arbor is taken 
 out and placed aside to have the burrs removed by rubbing 
 on emery paper. 
 
256 THE MODERN CLOCK. 
 
 ■This is one of the few instances in which automatic ma- 
 chinery has been unable to displace hand labor, as the work 
 is done so quickly that the time of the attendant would be 
 nearly all taken up in placing and removing the stacks, 
 and so the feeding is done by him as well. About 35,000 
 wheels per day can be thus cut by one man, with girls to 
 stack the blanks on the arbors, and an automatic feed would 
 not release the man from attendance on the machine, so 
 that the majority of clock wheels are cut to-day as they 
 were forty years ago. Still, some of the factories are add- 
 ing an automatic feed to the carriage in the belief that the 
 increased evenness of feed will give a more accurately cut 
 wheel, a proposition which the men most vigorously deny. 
 Such a machine, they say, to be truly automatic, miust take 
 its stacks of wheels from a magazine and discharge the 
 work when done, so that one attendant could look after a 
 number of machines. This would result in economy, as well 
 as accuracy, but has not been done owing to the great vari- 
 ations in sizes of wheels and numbers of teeth required in 
 clock work. 
 
 Figure 82 shows one of these machines, a photograph of 
 which was taken especially for us by the courtesy of the 
 Seth Thomas Clock Company at their factory in Thomas- 
 ton, Conn. 
 
 About every ten years some factory decides to try stamp- 
 ing out the teeth of wheels at the same time they are being 
 blanked ; this can, of course, be done by simply using a 
 more expensive punch and die, and at first it looks very at- 
 tractive ; but it is soon found that the cost of keeping up 
 such expensive dies makes the wheels cost more than if 
 regularly cut and for reasons of economy the return is 
 made to the older and better looking cut wheels. 
 
 After an acid dip to remove the scale on the sheet brass, 
 followed by a dip in lacquer, to prevent further tarnish, 
 the wheels are riveted on the pinions in a specially con- 
 structed jig which keeps them central during the rivetting 
 
THE MODERN CLOCK. 257 
 
 and when finished the truth of every wheel and its pinions 
 and pivots are all tested before they are put into the clocks. 
 The total waste on all processes in making wheels and pin- 
 ions is from two to five per cent, so that it will readily be 
 seen that accuracy is demanded by the inspectors. Euro- 
 pean writers have often found fault with nearly everything 
 else about the Yankee clock, but they all unite in agreeing 
 that the cutting and centering of wheels, pinions and pivots 
 (and the depthing) are perfect, while the clocks of Ger- 
 many, France, Switzerland and England (particularly 
 France) leave much to be desired in this respect; and much 
 of the reputation of the Yankee clock in Europe corties from 
 the fact that it will run under conditions which would stop 
 those of European make. 
 
 We give herewith a table of clock trains as usually manu- 
 factured, from which lost wheels and pinions may be easily 
 identified by counting the teeth of wheels and pinions which 
 remain in the movement and referring to th-e table. It will 
 also assist in getting the lengths of missing pendulums by 
 counting the trains and referring to the corresponding 
 length of pendulums. Thus, with 84 teeth in the center 
 wheel, 70 in the third, 30 in the escape and 7-leaf pinions, 
 the clock is 120 beat and requires a pendulum 9.78 inches 
 from the bottom of suspension to the center of the bob. 
 
 To Calculate Clock Trains. — Britten gives the fol- 
 lowing rule: Divide the number of pendulum vibrations 
 per hour by twice the number of escape wheel teeth; the 
 quotient will be the number of turns of escape wheel per 
 hour. Multiply this quotient by the number of escape 
 pinion teeth, and divide the product by the number of third 
 wheel. This quotient will be the number of times the teeth 
 of third wheel pinion must be contained in center wheel. 
 
 Take a pendulum vibrating 5,400 times an hour, escape 
 wheel of 30, pinions of 8, and third wheel of ']2. Theri 
 5,40CK-6o=90. And 90X8-^-72=10. That is, the center 
 
258 
 
 THE MODERN CLOCK. 
 
 Clock Trains and Lengths of Pendulums* 
 
 " 1 
 
 o 
 
 
 to , r! 
 
 If 
 
 5?'2 c 
 
 V) 
 
 ,o 
 
 c4 <1> 
 
 m 
 
 III 
 
 § 
 
 
 
 
 
 1 
 
 "c 
 
 
 
 
 120 90 75 
 
 10 10 9 
 
 Double 
 
 *30 
 
 156.56 
 
 96 76 
 
 8 
 
 30 
 
 114 
 
 10.82 
 
 
 
 31eg- 
 
 
 
 115 100 
 
 10 
 
 30 
 
 115 
 
 10-65 
 
 
 
 ffo' 
 
 
 
 84 78 
 
 7 
 
 26 
 
 115.9 
 
 10.49 
 
 120 90 90 
 
 10 9 9 
 
 *40 
 
 88.07 
 
 96 80 
 
 8 
 
 30 
 
 120 
 
 9.78 
 
 128 120 
 
 16 
 
 30 
 
 60 
 
 39.14 
 
 84 70 
 
 7 
 
 30 
 
 120 
 
 9.78 
 
 112 105 
 
 14 
 
 30 
 
 60 
 
 39.14 
 
 84 78 
 
 7 
 
 27 
 
 120.3 
 
 9.73 
 
 96 90 
 
 12 
 
 30 
 
 60 
 
 39.14 
 
 90 84 
 
 8 
 
 31 
 
 122 
 
 9.46 
 
 80 75 
 
 10 
 
 30 
 
 60 
 
 39.14 
 
 84 78 
 
 7 
 
 28 
 
 124.8 
 
 9.02 
 
 64 60 
 
 8 
 
 30 
 
 60 
 
 39.14 
 
 100 80 
 
 8 
 
 30 
 
 125 
 
 9.01 
 
 68 64 
 
 8 
 
 30 
 
 68 
 
 30.49 
 
 90 84 
 
 8 
 
 32 
 
 126 
 
 8.87 
 
 70 64 
 
 8 
 
 30 
 
 70 
 
 28.75 
 
 100 96 
 
 10 
 
 40 
 
 128 
 
 8.59 
 
 72 64 
 
 8 
 
 30 
 
 72 
 
 27.17 
 
 84 78 
 
 7 
 
 29 
 
 129.3 
 
 8.42 
 
 75 60 
 
 8 
 
 32 
 
 75 
 
 25.05 
 
 100 78 
 
 8 
 
 32 
 
 130 
 
 8.34 
 
 72 65 
 
 8 
 
 32 
 
 78 
 
 23.15 
 
 84 77 
 
 7 
 
 30 
 
 132 
 
 8.08 
 
 75 64 
 
 8 
 
 32 
 
 80 
 
 22.01 
 
 84 78 
 
 7 
 
 30 
 
 133.7 
 
 7.9 
 
 84 64 
 
 8 
 
 30 
 
 84 
 
 19.97 
 
 90 90 
 
 8 
 
 32 
 
 135 
 
 7.73 
 
 86 64 
 
 8 
 
 30 
 
 86 
 
 19.06 
 
 84 78 
 
 7 
 
 31 
 
 138.2 
 
 7.38 
 
 88 64 
 
 8 
 
 30 
 
 88 
 
 18.19 
 
 84 80 
 
 8 
 
 40 
 
 140 
 
 7.18 
 
 84 78 
 
 7 
 
 20 
 
 89.1 
 
 17.72 
 
 120 71 
 
 8 
 
 32 
 
 142 
 
 6.99 
 
 80 72 
 
 8 
 
 30 
 
 90 
 
 17.39 
 
 84 78 
 
 7 
 
 32 
 
 142.6 
 
 6.93 
 
 84 78 
 
 7 
 
 21 
 
 93.6 
 
 16.08 
 
 100 87 
 
 8 
 
 32 
 
 145 
 
 6.69 
 
 94 64 
 
 8 
 
 30 
 
 94 
 
 15.94 
 
 84 78 
 
 7 
 
 33 
 
 147.1 
 
 6.5 
 
 84 78 
 
 8 
 
 ■ 28 
 
 95.5 
 
 15.45 
 
 100 96 
 
 8 
 
 30 
 
 150 
 
 6.26 
 
 108 100 
 
 12&10 
 
 32 
 
 96 
 
 15.28 
 
 84 78 
 
 7 
 
 34 
 
 151.6 
 
 6.1 
 
 84 84 
 
 9& 8 
 
 30 
 
 98 
 
 14.66 
 
 96 95 
 
 8 
 
 32 
 
 152 
 
 6.09 
 
 84 78 
 
 7 
 
 22 
 
 98 
 
 14.66 
 
 84 77 
 
 7 
 
 35 
 
 154 
 
 5.94 
 
 84 78 
 
 8 
 
 29 
 
 98.9 
 
 14.41 
 
 104 96 
 
 8 
 
 30 
 
 156 
 
 5.78 
 
 80 80 
 
 8 
 
 30 
 
 100 
 
 14.09 
 
 84 78 
 
 7 
 
 35 
 
 156 
 
 5.78 
 
 85 72 
 
 8 
 
 32 
 
 102 
 
 13.54 
 
 120 96 
 
 9&8 
 
 30 
 
 160 
 
 5.5 
 
 84 78 
 
 8 
 
 30 
 
 102.4 
 
 13.44 
 
 84 78 
 
 7 
 
 36 
 
 160.5 
 
 5.47 
 
 84 78 
 
 7 
 
 23 
 
 102.5 
 
 13.4 
 
 84 78 
 
 7 
 
 37 
 
 164.9 
 
 5.15 
 
 105 100 
 
 10 
 
 30 
 
 105 
 
 12.78 
 
 132 100 
 
 9&8 
 
 27 
 
 165 
 
 5.17 
 
 84 78 
 
 8 
 
 31 
 
 105.8 
 
 12.59 
 
 84 78 
 
 7 
 
 38 
 
 169.4 
 
 4.88 
 
 84 78 
 
 7 
 
 24 
 
 107 
 
 12.3 
 
 128 102 
 
 8 
 
 25 
 
 170 
 
 4.87 
 
 96 72 
 
 8 
 
 30 
 
 108 
 
 12.08 
 
 84 78 
 
 7 
 
 39 
 
 173.8 
 
 4.65 
 
 84 78 
 
 8 
 
 32 
 
 109.2 
 
 11.82 
 
 36 36 35 
 
 6 
 
 25 
 
 175 
 
 4.6 
 
 88 80 
 
 8 
 
 30 
 
 110 
 
 11.64 
 
 84 77 
 
 7 
 
 40 
 
 176 
 
 4.55 
 
 84 77 
 
 7 
 
 25 
 
 110 
 
 11.64 
 
 84 78 
 
 7 
 
 40 
 
 178.3 
 
 4.43 
 
 84 78 
 
 7 
 
 25 
 
 111.4 
 
 11.35 
 
 45 36 36 
 
 6 
 
 20 
 
 180 
 
 4.35 
 
 84 80 
 
 8 
 
 32 
 
 112 
 
 11.22 
 
 47 36 36 
 
 6 
 
 20 
 
 188 
 
 3.99 
 
 84 78 
 
 8 
 
 33 
 
 112.6 
 
 11.11 
 
 
 
 
 
 
 *These are good examples of turret clock trains; the great wheel (120 teeth) 
 malces in both instances a rotation in three hours, From this wheel the hands 
 are to be driven. This may be done by means of a pinion of 40 gearing with the 
 great wheel, or a pair of bevel wheels bearing the same proportion to each 
 other (three to one) may be used, the larger one being fixed to the great wheel 
 arbor. The arrangement would in each case depend upon the number and posi- 
 tion of the dials. The double three-legged gravity escape wheel moves through 
 60° at each beat, and therefore to apply the rule given for calculating clock 
 •trains it must be treated as an escape wheel of three teeth. 
 
THE MODERN CLOCK. 
 
 259 
 
 wheel must have ten times as many teeth as the third wheel 
 pinion, or ten times 8=80. 
 
 The center pinion and great wheel need not be consid- 
 ered in connection with the rest of the train, but only in 
 relation to the fall of the weight, or turns of mainspring, 
 as the case may be. Divide the fall of the weight (or twice 
 the fall, if double cord and pulley are used) by the circum- 
 ference of the barrel (taken at the center of the cord) ; 
 the quotient will be the number of turns the barrel must 
 make. Take this number as a divisor, and the number of 
 turns made by the center wheel during the period from 
 winding to winding as the dividend; the quotient will be 
 the number of times the center pinion must be contained in 
 the great wheel. Or if the numbers of the great wheel and 
 center pinion and the fall of the weight are fixed, to find 
 the circumference of the barrel, divide the number of turns 
 of the center wheel by the proportion between the center 
 pinion and the great wheel ; take the quotient obtained as a 
 divisor, and the fall of the weight as a dividend (or twice 
 the fall if the pulley is used), and the quotient will be the 
 circumference of the barrel. To take an ordinary regulator 
 or 8-day clock as an example — 192 (number of turns of 
 center pinion in 8 days)-i-i2 (proportion between center 
 pinion and barrel wheel) := 16 (number of turns of barrel). 
 Then if the fall of the cord^ 40 inches, 40X2-^16=5, 
 which would be circumference of barrel at the center of the 
 cord. 
 
 If the numbers of the wheels are given, the vibrations per 
 hour of the pendulum may be obtained by dividing the prod- 
 uct of the wheel teeth multiplied together by the product of 
 the pinions multiplied together, and dividing the quotient by 
 twice the number of escape wheel teeth. 
 
 The numbers generally used by clock makers for clocks 
 with less than half-second pendulum are center wheel 84, 
 gearing with a pinion of 7 ; third wheel 78, gearing with a 
 pinion of 7. 
 
26o' THE MODERN CLOCK. 
 
 ■ The' product obtained by multiplying too^ether the center 
 pnd third wheels=84X78=6,552. The two pinions multi- 
 plied tcgether=7X7=49- Then 6,552^-49=133.7. So 
 that for every turn of the center wheel the escape pinion 
 turns 133.7 times. Or 133.7-^60=2.229, which is the num- 
 ber of turns in a minute of the escape pinion. 
 
 The length of the pendulum, and therefore the number 
 of escape wheel teeth, in clocks of this class is generally de- 
 cided with reference to the room to be had in the clock 
 case, with this restriction, the escape wheel should not have 
 less than 20 nor more than 40 teeth, or the performance will 
 not be satisfactory. The length of the pendulum for all 
 escape wheels within this limit is given in the preceding 
 table. The length there stated is of course the theoretical 
 length, and the ready rule adopted by clockmakers is 
 to measure from the center arbor to the bottom of the 
 inside of the case, in order to ascertain the greatest length 
 of pendulum which can be used. For instance, if 
 from the center arbor to the bottom of the case is 10 inches, 
 they would decide to use a lo-inch pendulum, and cut the 
 escape wheel accordingly with the number of teeth required 
 as shown in the table. But they would make the pendulum 
 rod of such a length as just to clear the bottom of the case 
 when the pendulum was fixed in the clock. 
 
 In the clocks just referred to the barrel or first wheel 
 has 96 teeth, and gears with a pinion of eight. 
 
 Month clocks have an intermediate wheel and pinion be- 
 tween the great and center wheels. This extra wheel and 
 pinion must have a proportion to each other of 4 to i to 
 enable the 8-day clock to go 2i'^ days from winding to wind- 
 ing. The weight will have to be four times as h^avy, plus 
 the extra friction, or if the same weight is used there must 
 be a proportionately longer fall. 
 
 Six-months clock have two extra wheels and pinions be- 
 tween the great and center wheels, one pair having a pro- 
 portion of 4^ to I and the other of 6 to i. But there is an 
 
THE MODEliX CLOCK.J rlJl^j^ Af 4 o ^ 
 
 enormous amount of extra friction generated in these clocks, 
 and they are not to be recommended. 
 
 The pivot holes and all the other holes in the frames, are 
 punched at one operation after the frames have been 
 blanked and flattened. They are placed in the press, and 
 a large die having punches in it of the proper size and 
 in the right position for the holes, comes down on the frame 
 and makes the holes with great rapidity and accuracy. 
 These holes are finished afterwards by a broach. In some 
 kinds of clocks, where some of the pivot holes are very 
 small, the small holes are simply marked with a sharp point 
 in the die, and afterwards drilled by small vertical drills. 
 These machines are very convenient for boring a number 
 of holes rapidly. The drill is rotated with great speed, and 
 a jig or plate on which the work rests is moved upwards 
 towards the drill by a movement of the operator's foot. All 
 the boring, countersinking, etc., in American clocks, is done 
 through the agency of these drills. Bending the small 
 wires for the locking work, the pendulum ball, etc., is rap- 
 idly effected by forming. As no objectionable marks have 
 been made on the surface of either the thick or smaller 
 wires during any process of construction, all that is neces- 
 sary to finish the iron work is simply to clean it well, which 
 is done in a very effective manner by placing a quantity of 
 work in a revolving tumbling box, which is simply a barrel 
 containing a quantity of saw-dust. 
 
 Milling the winding squares on barrel arbors is an in- 
 genious operation. The machine for milling squares and 
 similar work is made on the principle of a wheel-cutting en- 
 gine. The work is held in a frame, attached to which is a 
 small index plate, like that of a cutting engine. In the ma- 
 chine two large mills or cutters, with teeth in them like a 
 file, are running, and the part to be squared is moved in 
 between the revolving cutters, which operation immediately 
 forms two sides of the square. The work is then drawn 
 back, and the index turned round, and in a like manner the 
 
262 THE MODERN CLOCK. 
 
 other two sides of the square are formed. The cutting- 
 sides of the mills are a little bevelled, so that they will pro- 
 duce a slight taper on the squares. 
 
 Winding keys have shown great improvements. Some 
 manufacturers originally used cast iron ones, but the squares 
 were never good in them, and brass ones were adopted. At 
 first the squares were made by first drilling a hole and driv- 
 ing a square punch in with a hammer; and to make the 
 squares in eighteen hundred keys by this method was con- 
 sidered a good day's work. Restless Yankee ingenuity, 
 however, has contrived a device by which twenty or twen- 
 ty-five thousand squares can be made in a day, while at the 
 same time they are better and straighter squares than those 
 by the old method; but we are not at hberty to describe 
 the process at present, but only to state that it is done 
 by what machinists call drilHng a square hole. 
 
 Pendulum rods are made from soft iron wire, and the 
 springs on the ends rolled out by rollers. Two operations 
 are necessary. The first roughs the spring out on rollers 
 of eccentric shape, and the spring is afterwards finished on 
 plain smooth rollers. The pendulum balls in the best clocks 
 are made of lead, on account of its weight, and cast in an 
 iron mold in the same manner as lead bullets, at the rate 
 of about eighteen hundred a day. A movable mandrel is 
 placed in the mold to produce the hole that is in the center 
 of the ball. The balls are afterwards covered with a shell 
 of brass, polished with a blood-stone burnisher. The vari- 
 ous cocks used in these clocks are all struck up from sheet 
 brass, and the pins in the wheels in the striking part are all 
 swedged into their shape from plain wire. The hands are 
 die struck out of sheet steel, and afterwards polished on 
 emery belts, and blued in a furnace. 
 
 All the little pieces of these clocks are riveted together by 
 hand, and the different parts of the movement, when com- 
 plete, are put together by workmen continually employed 
 in that department. Although the greatest vigilance is used 
 
THE MODERN CLOCK. 26^ 
 
 in constructing the different parts to see that they are per- 
 fect, when they come to be put together they are subjected 
 to another examination, and after the movements are put 
 in the, case the clocks are put to the test by actual trial be- 
 fore they are packed ready for the market. As a general 
 rule, all the different operations are done by workmen em- 
 ployed only at one particular branch; and in the largest 
 factories from thirty to fifty thousand clocks of all classes 
 may be seen in the various stages of construction. 
 
 Such is a description of the main points in which the man- 
 ufacture of American clock movements differs from those 
 manufactured by other systems. All admit that these clocks 
 perform the duties for which they are designed in an ad- 
 mirable manner, while they require but little care to m.an- 
 age, and when out of order but little skill is necessar^^ to 
 repair them. Of late years there has been a growing de- 
 mand for ornamental mantel-piece clocks in metallic cases 
 of superior quality, and large numbers of these cases of 
 both bronze and gold finish are being manufactured, which, 
 for beauty of design and fine execution, in many instances 
 rival those of French production. The shapes of the ordi- 
 nary American movements were, however, unsuitable for 
 some patterns of the highest class of cases, and the full plate, 
 round movements of the same size as the French, but with 
 improvements in them that in some respects render them 
 more simple than the French, are now manufactured. Ex- 
 actly the same system is employed in the manufacture of 
 the different parts of these clocks that is practiced in mak- 
 ing the ordinary American movements. 
 
CHAPTER XV. 
 
 SPRINGS, WEIGHTS AND POWER. 
 
 We see by the preceding calculations that there is one 
 definite point in the time train of a clock ; the center arbor, 
 which carries the minute hand, must revolve once in one 
 hour; from this point we may vary the train both ways, 
 toward the escape wheel to suit the length of pendulum 
 which we desire to use, and toward the barrel to suit the 
 length of time we want the clock to run. The center arbor 
 is therefore generally used as the point at which to begin 
 calculations, and it is also for this reason that the number 
 of teeth in the center wheel is the starting point in train 
 calculations toward the escape wheel, while the center pinion 
 is the starting point in calculations of the length of time the 
 weight or spring is to drive the clock. Most writers on 
 horology ignore this point, because it seems self-evident, 
 but its omission has been the cause of much mystification 
 to so many students that it is better to state it in plain terms, 
 so that even temporary confusion may be avoided. 
 
 Sometimes there is a second fixed point in a time train ; 
 this occurs only when there is a seconds hand to be provided 
 for; when this is the case the seconds hand must revolve 
 once every minute. If it is a seconds pendulum the hand is 
 generally carried on the escape wheel and the relation of 
 revolutions between the hour and seconds wheels must then 
 be as one is to sixty. This might be accomplished with a 
 single wheel having sixty times as many teeth as the pinion 
 on the seconds arbor ; but the wheel would take up so much 
 room, on account of its large circumference, that the move- 
 ment would become unwieldly because there would be no 
 room, left for the other wheels; so it is cheaper to make 
 
 264 
 
THE MODERN CLOCK. 265 
 
 more wheels and pinions and thereby get a smaller clock. 
 Now the best practical method of dividing this motion is by 
 giving the wheels and pinions a relative velocity of seven 
 and a half and eight, because 7.5 X 8 = 60. 
 
 Thus if the center wheel has 80 teeth, gearing into a 
 pinion of 10, the pinion will be driven eight times for each 
 revolution of the center wheel, while the third wheel, with 
 75 teeth, will drive its pinion of 10 leaves 7.5 times, so that 
 this arbor will go 7.5 times eight, or 60 times as fast as the 
 center wheel. 
 
 If the clock has no seconds hand this second fixed point 
 is not present in the calculations and other considerations 
 may then govern. These are generally the securing of an 
 even motion, with teeth of wheels and pinions properly 
 meshing into each other, without incurring undue expense 
 in manufacture by making too many teeth in the pinions 
 and consequently in the wheels. For these reasons pinions 
 of less than seven or more than ten leaves are rarely used 
 in the common clocks, although regulators and fine clocks, 
 where the depthing is important, frequently have 12, 14 or 
 16 leaves in the pinions, as is also the case with tower clocks, 
 where the increased size of the movement is not as impor- 
 tant as a smoothly running train. Clocks without pendu- 
 lums, carriage clocks, locomotive levers and nickel alarms, 
 also have different trains, many of which have the six leaf 
 pinion, with its attendant evils, in their trains. 
 
 Weights. — Weights have the great advantage of driving 
 a train with uniform power, which a spring does not ac- 
 complish : They are therefore always used where exactness 
 of time is of more importance than compactness or porta- 
 bility of the clock. In making calculations for a weight 
 movement, the first consideration is that as the coils of the 
 cord must be side by side upon the barrel and each takes up 
 a definite amount of space, a thicker movement (with longer 
 arbors) will be necessary, as the barrel must give a suf- 
 
266 THE MODERN CI.OCK. 
 
 ficient number of turns of the cord to run the clock the 
 desired time and the length of the barrel, with the wheel and 
 maintaining power all mounted upon the one arbor, will de- 
 termine the thickness of the movement. If the clock is to 
 have striking trains their barrels will generally be of more 
 turns and consequently longer than the time barrel and in 
 that case the distance between the plates is governed by 
 the length of the longest barrel and its mechanism. 
 
 The center wheel, upon the arbor of which sits the canon 
 pinion with the minute hand, must, since the hand has to 
 accomplish its revolution in one hour, also revolve once in 
 an hour. When, therefore, the pinion of the center arbor 
 has 8 leaves and the barrel wheel 144, then the 8 pinion 
 leaves, which makes one revolution per hour, would require 
 the advancing of 8 teeth of the barrel wheel, which is equal 
 to the eighteenth part of its circumference. But when the 
 eighteenth part in its advancing consumes i hour, then the 
 entire barrel wheel will consume 18 hours to accomplish one 
 revolution. If, now, 10 coils of the weight cord were laid 
 around the barrel, the clock would then run 10 X 18 = 180 
 hours, or 7^. days, before it is run down. 
 
 Referring to what was said in a previous chapter on 
 wheels being merely compound levers, it will be seen that 
 as we gain motion we lose power in the same ratio. We 
 shall also see that by working the rule backwards we may 
 arrive at the amount of force exerted on the pendulum by 
 the pallets. If we multiply the circumference of the escape 
 wheel in inches by the number of its revolutions in one hour 
 we will get the number of inches of motion the escape wheel 
 has in one hour. Now if we multiply the weight by the 
 distance the barrel wheel travels in one hour and divide by 
 the first number we shall have the force exerted on the es- 
 cape wheel. It will be simpler to turn the weight into grains 
 before starting, as the division is less cumbersome. 
 
 Another way is to find how many times the escape wheel 
 revolves to one turn of the barrel and divide the weisrht 
 
THE MODERN CLOCK. 267 
 
 by that number, which will give the proportion of weight 
 at the escape wheel, or rather would do so if there were no 
 power lost by friction. It is usual to estimate that three- 
 quarters of the power is used up in frictions of teeth and 
 pivots, so that the amount actually used for propulsion of 
 the pendulum is very small, being merely sufficient to over- 
 come the bending moment of the suspension spring and the 
 resistance of the air. 
 
 It is for this reason that clocks with finely cut trains and 
 jeweled pivots, thus having little train friction, will run 
 with very small weights. The writer knows of a Howard 
 regulator with jeweled pivots and pallets running a 14- 
 pound pendulum with a five-ounce driving weight. Of 
 course this is an extreme instance and was the result of an 
 experiment by an expert watchmaker who wanted to see 
 what he could do in this direction. 
 
 Usually the method adopted to determine the amount of 
 weight that is necessary for a movement is to hang a small 
 tin pail on the weight cord and fill it with shot sufficient to 
 barely make the clock keep time. When this point has been 
 determined, then weigh the pail of shot and make your driv- 
 ing weight from eight to sixteen ounces heavier. In doing 
 this be sure the clock is in beat and that it is the lack of 
 power which stops the clock ; the latter point can be readily 
 determined by adding or taking out shot from the pail until 
 the amount of weight is determined. The extra weight is 
 then added as a reserve power, to counteract the increase 
 of friction produced by the thickening of the oil. 
 
 Many clock barrels have spiral grooves turned in them 
 to assist in keeping the coils from riding on each other, as 
 where such riding occurs the riding coils are farther from 
 the center of the barrel than the others, which gives them a 
 longer leverage and greater power while they are unwinding, 
 so that the power thus becomes irregular and affects the rate 
 of the clock, slowing it if the escapement is dead beat and 
 making it go faster if it is a recoil escapement. 
 
268 THE MODERN CLOCK. 
 
 Clock cords should be attached to the barrel at the end 
 which is the farthest from the pendulum, so that as they un- 
 wind the weight is carried away from the pendulum. This 
 is done to avoid sympathetic vibrations of the weight as it 
 passes the pendulum, which interfere with the timekeeping 
 when they occur. If the weight cannot be brought far 
 enough away to avoid vibrations a sheet of glass may be 
 drilled at its four corners and fixed with screws to posts 
 placed in the back of the case at the point where vibration 
 occurs, so that the glass is between the pendulum rod and 
 the weight, but does not interfere with either. This looks 
 well and cures the trouble. 
 
 We have, heretofore, been speaking of weights which 
 hang directly from the barrel, as was the case with the older 
 clocks with long cases, so that the weight had plenty of 
 room to fall. Where the cases are too short to allow of this 
 method, recourse is had to hanging the weight on a pulley 
 and fastening one end of the cord to the seat board. This 
 involves doubling the amount of weight and also taking 
 care that the end of the cord is fastened far enough from 
 the slot through which it unwinds so that the cords will 
 not twist, as they are likely to do if they are near together 
 and the cord has been twisted too much while putting it on 
 the barrel. Twisting weight cords are a frequent source of 
 trouble when new cords have been put on a clock. The 
 pulley is another source of trouble, especially if wire cords 
 (picture cords) or cables are used. Wire cable should not 
 be bent in a circle smaller than forty times its diameter if 
 flexibility is to be maintained, hence pulleys which were all 
 right for gut or silk frequently prove too small when wire 
 is substituted and kinks, twisted and broken cables frequent- 
 ly result from this cause. This is especially the case with 
 the heavy weight of striking trains of hall and chiming 
 clocks, where double pulleys are used, and also leads to 
 trouble by jamming and cutting the cables and dropping 
 of the weights in tower clocks where a new cable of larger 
 
THE MODERN CLOCK. 269 
 
 size is used to replace an old one which has become unsafe 
 from rust, or cut by the sheaves. 
 
 Weight cords on the striking side of a clock should al- 
 ways be left long enough so that they will not run down 
 and stop before the time train has stopped. This is particu- 
 larly the case with the old English hall clocks, as many of 
 them will drop or push their gathering racks free of the 
 gathering pinion under such conditions and then when the 
 clock is wound it will go on striking continuously until the 
 dial is taken off and the rack replaced in mesh with the gath- 
 ering pinion. As clocks are usually wound at night, the 
 watchmaker can see the disturbance that would be caused 
 in a house in the "wee sma' hours" by such a clock going 
 on a rampage and striking continuously. 
 
 Oiling Cables.- — Clock cables, if of wire and small in 
 size, should be oiled by dipping in vaseline thinned with 
 benzine of good quality. Both benzine and vaseline must 
 be free from acid, as if the latter is present it will attack the 
 cable. This thinning will permit the vaseline to permeate 
 the entire cable and when the benzine evaporates it will 
 leave a thin film of vaseline over every wire, thus prevent- 
 ing rust. Tower clock cables should be oiled with a good 
 mineral oil, well soaked into them to prevent rusting. Gut 
 clock cords, when dry and hard, are best treated with clock 
 oil, but olive oil or sperm oil will also be found good to 
 .soften and preserve them. New cords should always be 
 oiled until they are soft and flexible. If the weight is under 
 ten pounds silk cords are preferable to gut or wire as they 
 are very soft and flexible. 
 
 In putting on a new cable or weight cord the course of 
 the weight and cord should be closely watched at all points, 
 to see that they remain free and do not chafe or bind any- 
 w^here and also that the coils run evenly and freely, side by 
 side ; sometimes, especially with wire, a new cable gets 
 kinked by riding^ the first time of winding: and is then very 
 
270 THE MODERN CLOCK. 
 
 difficult to cure of this serious fault. Another point to 
 watch is to see that the position of the cord when wound up 
 will not cause an end thrust upon the barrel, which will in- 
 terfere with the time keeping if it is overwound, so that the 
 weight is jammed against the seatboard; this frequently 
 happens with careless winding, if there is no stop work. 
 
 To determine the lengths of clock cords or weights, we 
 may have to approach the question from either end. If 
 the clock be brought in without the cords, we first count 
 the number of turns we can get on the barrel. This may be 
 done by measuring the length of the barrel and dividing it 
 by the thickness of the cord, if the barrel is smooth, or by 
 counting the grooves if it be a grooved barrel. Next we 
 caliper the diameter and add the thickness of one cord, which 
 gives us the diameter of the barrel to the center of the 
 cords, which is the real or working diameter. Multiply the 
 distance so found by 3. 141 56, which gives the circumference 
 of the barrel, or the length of cord for one turn of the bar- 
 rel. Multiply the length of one turn by the number of turns 
 and we have the length of cord on the barrel, when it is 
 fully wound. If the cord is to be attached to the weight, 
 measure the distance from the center of barrel to the bottom 
 of the seat board and leave enough for tieing. If the weight 
 is on a pulley it will generally require about twelve inches 
 to reach from the barrel through the slot of the seat board, 
 through the pulley to the point of fastening. 
 
 To get the fall of the weight, stand it on the bottom of 
 the case and measure the distance .from the top of the 
 point of attachment to the bottom of the seat board. This 
 will generally allow the weight to fall within two inches of 
 the bottom and thus keep the cable tight when the clock runs 
 down; thus avoiding kinks and over-riding when we wind 
 again after allowing the clock to run down. If the weight 
 has a pulley and double cord, measure from the top of the 
 pulley to the seatboard, with the weight on the bottom, and 
 then double this measurement for the length of the cord. 
 
THE MODERN CLOCK. 
 
 71 
 
 This measure is multiplied by as many times as there are 
 pulleys in the case of additional sheaves. Striking trains 
 are frequently run with two coils or layers of cord, on the 
 barrel, time trains never have but one. 
 
 Now, having the greatest available length of cord deter- 
 mined according either of the above conditions, we can de- 
 termine the number of turns for which we have room on 
 our barrel and divide the length of cord by the number of 
 turns. This will give us the length of one turn of the cord 
 on our barrel and thus having found the circumference it is 
 easy to find the diameter which we must give our barrel in 
 suiting a movement to given dimensions of the case. This 
 is frequently done where the factory may want a movement 
 to fit a particular style and size of case which has proved 
 popular, or when a watchmaker desires to make a movement 
 for which he has, or will buy, a case already made. 
 
 As to tower clock cables, getting the length of cable on 
 the barrel is, of course, the same as given above, but the 
 rest of it is an individual problem in every case, as cables 
 are led so differently and the length of fall varies so that 
 only the professional tower clock men are fitted to make 
 the measurements for new work and they require no in- 
 struction from me. It might be well to add, however, that 
 in the tower clocks by far the greater part of the cable is 
 always outside the clock and only the inner end coils and 
 uncoils about the barrel. It is for this reason that the outer 
 ends of the cables are so generally neglected by watchmakeri' 
 in charge of tower clocks and allowed to cut and rust until 
 they drop their weights. Caretakers of tower clocks should 
 remember that the inner ends of cables are always the best 
 ends ; the parts that need watching are those in the sheaves 
 or leading to the sheaves. Tower clocks should have the 
 cables marked where to stop to prevent overwinding. 
 
 In chain drives for the weights of cuckoo and other clocks 
 with exposed weights, we have generally a steel sprocket 
 wheel with convex guiding surfaces each side of the 
 
272 THE MODERN CLOCK. 
 
 sprocket and projecting flanges each side of the guides; one 
 of these flanges is generally the ratchet wheel. The ratchet 
 wheel, guide, sprocket, guide and flange, form a built-up 
 wheel which is loose on the arbor and is pinned close to the 
 great wheel, which is driven by a click on the wheel working 
 into the ratchet of the drive. It must be loose on the arbor, 
 because the clock is wound by pulling the sprocket and 
 ratchet backward by means of the chain until the weight is 
 raised clear up to the seat board. There are no squares on 
 the arbors, w^hich have ordinary pivots at both ends, and 
 the great wheel is fast on the arbor. The diameter of the 
 convex portion of the wheel each side of the sprocket is the 
 diameter of the barrel, and the chain should fit so that alter- 
 nate links will fit nicely in the teeth of the sprocket ; where 
 this is not the case they will miss a link occasionally and the 
 weight will then fall until the chain catches again, when it 
 will stop with a jerk; bent or jammed links in the chain will 
 do the sam?i thing. Sometimes a light chain on a heavy 
 weight will stretch or spread the links enough to make their 
 action faulty. If examination shows a tendency to open the 
 links, they should be soldered; if they are stretching, a 
 heavier chain of correct lengths of links should be substi- 
 tuted. Twisted chains are another characteristic fault and 
 are usually the result of bent or jammed links. A close 
 examination of such a chain will generally reveal several 
 links in succession which are not quite flat and careful 
 straightening of these links will generally cure the tendency 
 to twist. 
 
 Mainsprings for Clocks. — There are many points of 
 difference between mainsprings for clocks and those for 
 watches. They differ in size, strength, number of coils and 
 in their eflfect on the rates of the clock. 
 
 Watch springs are practically all for 30-hour lever es- 
 capements, with a few cylinder, duplex and chronometer 
 escapements. If a fusee watch happens into a shop nowa- 
 
THE MODERN CLOCK. 
 
 273 
 
 days it is so rare as to be a curiosity worth stopping work 
 to look at. 
 
 The clocks range all the way from 30 hours to 400 days in 
 length of time between windings and include lever, cylinder, 
 duplex, dead beat, half dead beat, recoil and other escape- 
 ments. Furthermore some of these, even of the same form 
 of escapements, will vary so in weight and the consequent 
 influence of the spring that what will pass in one case will 
 give a wildly erratic rate in another instance. Many of the 
 small French clocks have such small and light pendulums 
 that very nice management of the stop works is necessary 
 to prevent the clock from gaining wildly when wound or 
 stopping altogether when half run down. 
 
 Nothing will cause a clock with a cylinder escapement 
 to vary in time more than a set or gummy m.ainspring, for 
 it will gain time when first wound and lose when half run 
 down, or when there is but little power on the train. In 
 such a case examine the mainspring and see that it is neither 
 gummy nor set. If it is set, put in a new spring and you can 
 probably bring it to time. 
 
 With a clock it depends entirely on the kind of escape- 
 ment that it contains, w^hether it runs fastei or slower, with 
 a stronger spring; if you put a stronger mainspring in a 
 clock that contains a recoil escapement the clock will gain 
 time, because the extra power, transmitted to the pallets will 
 cause the pendulum to take a shorter arc, therefore gain 
 time, where the reverse occurs in the dead-beat escapement. 
 A stronger spring will cause the dead-beat pendulum to take 
 a longer arc and therefore lose time. 
 
 If a pendulum is short and light these effects will be much 
 greater than with a long and heavy pendulum. 
 
 At all clock factories they test the mainsprings for power 
 and to see that they unwind evenly ; those that do are marked 
 No. I, and those that do not are called ''seconds." The sec- 
 onds are used only for the striking side of the clocks, while 
 the perfect ones are used for the running, or time side. 
 
274 
 
 THE MODERN CLOCK. 
 
 Sometimes, however, a seconds' spring will be put on the 
 time side and will cause the clock to vary in a most erratic 
 way. This changing of springs is very often done by care- 
 less or ignorant workmen in cleaning and then they cannot 
 locate the trouble. 
 
 All mainsprings for both clocks and watches should be 
 smooth and well polished. Proper attention to this one item 
 will save many dollars' worth of time in examining move- 
 ments to try to detect the cause of variations. 
 
 A rough mainspring (that is, an emery finished main- 
 spring) will lose one-third of its power from coil friction, 
 and in certain instances even one-half. The deceptive fea- 
 ture about this to the watchmaker is that the clock will take 
 a good motion with a rough spring fully found, but v/ill fall 
 off when partly unwound, and the consequence is that he 
 finds a good motion when the spring is put in and w^ound, 
 and he afterward neglects to examine the spring w^hen he 
 examines the rate as faulty. The best springs are cheap 
 enough, so that only the best quality should be used, as it 
 is easy for a watchmaker to lose three or four dollars' worth 
 of time looking for faults in the escapement, train and ev- 
 erywhere else, except the barrel, when he has inserted a 
 rough, thick, poorly made spring. The most that he can 
 save on the cheaper qualities of springs is about five cents 
 per spring and we will ask any watchmaker how long it 
 would take to lose five cents in examination of a movement 
 to see what is defective. 
 
 Here is something which you can try yourself at the 
 bench. Take a rough watch mainspring; coil it small 
 enough to be grasped in the hand and then press on the 
 spring evenly and steadily. You will find it difficult to make 
 the coils slide on one another as the inner coils get smaller ; 
 they will stick together and give way by jerks. Now open 
 your hand slowly and you will feel the spring uncoiling in 
 an abrupt, jerky way, sometimes exerting very little pressure 
 on the hand, at other times a great deal. A dirty, gummy 
 
THE MODERN CLOCK. 
 
 275 
 
 spring will do the same thing. Now take a clean, well pol- 
 ished spring and try it the same way ; notice how much more 
 even and steady is the pressure required to move the coils 
 upon each other, either in compressing or expanding. Now 
 oil the well polished spring and try it again. You will find 
 you now have something that is instantly responding, evenly 
 and smoothly, to every variation of pressure. You can also 
 compress the spring two or three turns farther with the 
 same force. This is what goes on in the barrel of every 
 clock or watch; you have merely been using your hand as 
 a barrel and feeling the action of the springs. 
 
 Now a well finished mainspring that is gummy is as ir- 
 regular in its action as the worst of the springs described 
 above, yet very few watchmakers will take out the springs 
 of a clock if they are in a barrel. One of them once said to 
 me, "Why, who ever takes out springs? I'll bet I clean a 
 hundred clocks before I take out the springs of one of 
 them!" Yet this same man had then a clock which had 
 come back to him and which was the cause of the conver- 
 sation. 
 
 There must be in this country over 25,000 fine French 
 clocks in expensive marble or onyx cases, which were given 
 as wedding presents to their owners, and which have never 
 run properly and in many instances cannot be made to run 
 by the watchmakers to whom they were taken when they 
 stopped. Let me give the history of one of them. It was an 
 eight-day French marble clock which cost $25 (wholesale) 
 in St. Louis and was given as a wedding present. Three 
 months later it stopped and was taken to a watchmaker well 
 known to be skillful and who had a fine run of expensive 
 watches constantly coming to him. He cleaned the clock, 
 took it home and it ran three hours ! It came back to him 
 three times; during these periods he went over the move- 
 ment repeatedly ; every wheel was tested in a depthing tool 
 and found to be round : all the teeth were examined sepa- 
 rately under a glass and found to be perfect; the pinions 
 
276 T'lE MODERN CLOCK. 
 
 were subjected to the same careful scrutiny; the depthings 
 were tried with each wheel and pinion separately ; the pivots 
 were tested and found to be right; the movement was put 
 in its case and examined there; it would run all right on 
 the watchmaker's bench/ but not in the home of its owner. 
 It would stop every time it was moved in dusting the man- 
 tel. He became disgusted and took the clock to another 
 watchmaker, a railroad time inspector; same results. In 
 this way the clock moved about for three years ; whenever 
 the owner heard of a man who was accounted more than 
 ordinarily skillful he took him the clock and watched him 
 ''fall down" on it. Finally it came into the hands of an 
 ex-president of the American Horological Society. He 
 made it run three weeks. When he found the clock had 
 stopped again he refused pay for it. Three months later he 
 called and got the clock, kept it for three weeks, brought it 
 back without explanation and lo, the clock ran! It would 
 even run considerably out of beat! When asked what he 
 had done to the clock, he merely laughed and said "Wait.'* 
 
 A year later the clock was still going satisfactorily and he 
 explained. "That was the first time I ever got anything I 
 couldn't fix and it made me ashamed. I kept thinking it 
 over. Finally one night in bed I got to considering why a 
 clock wouldn't run when there was nothing the matter with 
 it. The only reason I could see was lack of power. Next 
 morning I got the clock and put in new mainsprings, the best 
 I could find. The clock was cured ! None of these other 
 men who had the clock took out the springs. They came 
 to me all gummed up, while the rest of the clock was clean, 
 bright and in perfect order, I cleaned the springs and re- 
 turned the clock ; it ran three weeks. When I took it back 
 I put in stronger springs, because I found them a little soft 
 on testing them. If any of your friends have French clocks 
 that won't go, send them to me." 
 
 Three-quarters of the trouble with French clocks is in 
 the spring box; mainspring too weak, gummy or set; stop 
 
THE MODERN CLOCK. 277 
 
 works not properly adjusted, or left off by some numskull 
 who thought he could make the clock keep time without it 
 when the maker couldn't; mainspring rough, so that it un- 
 coils by jerks ; spring too strong, so that the small and light 
 pendulum cannot control it. These will account for far 
 more cases than the ''flat wheel" story that so often comes 
 to the front to account for a failure on the part of the work- 
 man. Of course he must say something to his boss to ac- 
 count for his failure and the ''wheels out of round" and 
 *'.the faulty depthing" have been standard excuses for French 
 clocks for a century. Of course they do occur, but not 
 nearly as often as they are credited with, and even then such 
 a clock may be made to perform creditably if the springs 
 are right. 
 
 Another source of trouble is buckled springs, caused by 
 some workman taking them out or putting them in the bar- 
 rel without a mainspring winder. There are many men 
 who will tell you that they never use a winder; they can 
 put any spring in without it. Perhaps they can, but there 
 comes a day when they get a soft spring that is too wide for 
 this treatment and they stretch one side of it, or bend, or 
 kink it, and then comes coil friction with its attendant evils. 
 These may not show with a heavy pendulum, but they are 
 certain to do so if it happens to be an eight-day movement 
 with light pendulum or balance, and this is particularly true 
 of a cylinder. 
 
 All springs should be cleaned by soaking in benzine or 
 gasoHne and rubbing with a rag until all the gum is ofi^ 
 them before they are oiled. Heavy springs may be wiped 
 by wrapping one or two turns of a rag around them and 
 pushing it around the coils. The spring should be well 
 cleaned and dried before oiling. A quick way of cleaning 
 is to wind the springs clear up; stick a peg in the escape 
 wheel ; remove the pallet fork ; plunge the whole movement 
 into a pail of gasoline large enough to cover it ; let it stand 
 until the gasoline has soaked into the barrels; remove the 
 
278 THE MODERN CLOCK. 
 
 peg and let the trains run down. The coils of the spring 
 will scrub each other in unwinding; the pivots will clean 
 the pivot holes and the teeth of wheels and pinions will clean 
 each other. Then take the clock apart for repairs. Springs 
 which are not in barrels should be wound up and spring 
 clamps put on them before taking down the clock. About 
 six sizes of these clamps (from 2^ inches to ^ inch) are 
 sufficient for ordinary work. 
 
 Rancid oilis also the cause of many "come-backs." Work- 
 men will buy a large bottle of good oil and leave it standing 
 uncorked, or in the sun, or too near a stove in winter time, 
 until it spoils. Used in this condition it will dry or gum in 
 a month or two and the clock comes back, if the owner is 
 particular; if not, he simply tells his friends that you can't 
 fix a clock and they had better go elsewhere with their 
 watches. 
 
 For clock mainsprings, clock oil, such as you buy from 
 material dealers, is recommended, provided it is intended 
 for French mainsprings. If the "lubricant is needed for 
 coarse American springs, mix some vaseline with refined 
 benzine and put it .on hberally. The benzine will dissolve 
 the vaseline and will help to convey the lubricant all over 
 the spring, leaving no part untouched. The liquid will then 
 evaporate, leaving a thin coating of vaseline on the spring. 
 
 It is best to let springs dow^n with a key made for the 
 purpose. It is a key with a large, round, wooden handle, 
 which fills the hand of the watchmaker when he grasps it. 
 Placing the key on the arbor square, with the movement 
 ►held securely in a vise, wind the spring until you can "re- 
 lease the click of the ratchet with a screwdriver, wire or 
 other tool; hold the click free of the ratchet and let the 
 handle of the key turn slowly round in the hand until the 
 spring is down. Be careful not to release the pressure on 
 the key too much, or it will get away from you if the spring 
 is strong, and will damage the movement. This is why the 
 handle is made so large, so that you can hold a strong 
 spring. 
 
THE MODERN CLOCK. 279 
 
 It is of great importance, if we wish to avoid variable 
 coil friction, that the spring should wind, from the very 
 starting, concentrically ; i. e., that the coils should commence 
 to wind in regular spirals, equidistant from each other, 
 around the arbor. In very many cases we find, when we 
 commence to wind a spring, that the innermost coil bulges 
 out on one side, causing, from the very beginning, a greater 
 friction of the coils on that side, the outer ones pressing 
 hard against it as you continue to wind, while on the outer 
 side of the arbor they are separated from each other by 
 quite a little space betw^een them, and that this bulge in the 
 first coil is overcome and becomes concentric to the arbor 
 only after the spring is more than half way wound up. Thia 
 necessarily produces greater and more variable coil friction. 
 When a spring is put into the barrel the innermost coil 
 should come to the center around the arbor by a gradual 
 sweep, starting from at least one turn around away irom 
 the other coils. Instead of that, we more often find it lay- 
 ing close to the outer coils to the very end, and ending 
 abruptly in the curl in the soft end that is to be next the 
 arbor. When this is the case in a spring of uniform thick- 
 ness throughout, it is mainly due to the manner of first 
 winding it from its straight into a spiral form. To obviate 
 it, I generally wind the first coils, say tw^o or three, on a 
 center in the winder, a trifle smaller than the regular one, 
 which is to be of the same diameter of the arbor center in 
 the barrel. You will find that the substitution of the regu- 
 lar center, afterwards, will not undo the extra bending thus 
 produced on the inner coils, and that the spring will abut 
 by a more gradual sw^eep at the center, and wind more con- 
 centrically. 
 
 The form of spring formerly used with a fusee in Eng- 
 lish carriage clocks and marine chronometers is a spring 
 tapering slightly in thickness from the inner end for a dis- 
 tance of two full coils, the thickness increasing as we move 
 away from the end, then continuing of uniform thickness 
 
28o THE MODERN CLOCK. 
 
 until within about a coil and a half from the other end, 
 when it again increases in thickness by a gradual taper. 
 The increase in the thickness towards the outer end will 
 cause it to cling more firmly to the wall of the barrel. The 
 best substitute for this taper on the outside is a brace added 
 to some of the springs immediately back of the hole. With 
 this brace, and the core of the winding arbor cut spirally, 
 excellent results are obtained with a spring of uniform thick- 
 ness throughout its entire length. Something, too, can be 
 done to improve the action of a spring that has no brace, 
 l)y hooking it properly to the barrel. The hole in the spring 
 on the outside should never be made close to the end ; on the 
 contrary, there should be from a half to three-quarters of an 
 inch left beyond the hole. This end portion will act as a 
 brace. 
 
 When the spring is down, the innermost coil of it should 
 form a gradual spiral curve towards the center, so as to 
 meet the arbor without forcing it to one side or the other. 
 This curve can be improved upon, if not correct, with suit- 
 ably shaped pliers; or it can be approximated by winding 
 the innermost coils first on an arbor a little smaller in diam- 
 eter than the barrel arbor itself. 
 
 Another and very important factor in the development of 
 the force of the spring is the proper length and thickness 
 of it. For any diameter of barrel there is but one length 
 and one thickness of spring that will give the maximum 
 number of turns to wind. This is conditioned by the fact 
 that the volume w^hich the spring occupies when it is down 
 must not be greater nor less than the volume of the empty 
 space around the arbor into which it is to be wound, so that 
 the outermost coil of the spring when fully wound will oc- 
 cupy the same place which the innermost occupies when it 
 is down. In a barrel, the diameter of whose arbor is one- 
 third that of the barrel, the condition is fulfilled when the 
 measure across the coils of the spring as it lays against the 
 wall of the barrel, is 0.39 of the empty space, or, taking the 
 
THE MODERN CLOCK. 281 
 
 diameter of the barrel as a comparison, 0.123 of the latter; 
 in other words, nearly one-eighth of the diameter of the 
 barrel. This is the width that will give the greatest number 
 of turns to wind, whatever may be the length or thickness 
 of any spring. If now we desire a spring to wind a given 
 number of turns, there is but one thickness and one length 
 of it that will permit it to do so. The thickness remaining 
 the same, if we make the spring longer or shorter, we re- 
 duce the number of turns it will wind; more rapidly by 
 making it shorter, less so by making it longer. It is there- 
 fore not only useless, but detrimental, to put into a barrel 
 a greater number of coils, or turns, than are necessary, not 
 only because it will reduce the number of turns the barrel 
 will wind, but it will produce greater coil friction by filling 
 up the space with more coils than are necessary. 
 
 A mainspring in the act of uncoiling in its barrel always 
 gives a number of turns equal to the difference between the 
 number of coils in the up and the down positions. Thus, if 
 17 be the number of coils when the spring is run down, and 
 25 the number when against the arbor, the number of turns 
 in uncoiling will be 8, or the difference between 17 and 2^. 
 
 The cause of breakage is usually, that the inner coils are 
 put to the greatest strain, and then the slightest flaw in the 
 steel, a speck of rust, grooves cut in the edges of the spring 
 by allowing a screwdriver to slip over them, or an unequal 
 effect of change of temperature, causes the fracture, and 
 leaves the spring free to uncoil itself with verv great rapid- 
 ity. 
 
 Now this sudden uncoiling means that the whole energy 
 of the spring is expended on the barrel in a very small frac- 
 tion of a second. In reality the spring strikes the inner side 
 of the rim of the barrel, a violent blow in the direction the 
 spring is turning, that is, backwards ; this is due to the 
 mainspring's inertia and its very high mean velocity. The 
 velocity is nothing at the outer end, where the spring is 
 fixed, but rises to the maximum at the point of fracture, and 
 
282 THE MODERN CLOCK. 
 
 the kinetic energy at various points of the spring could no 
 doubt be calculated mathematically or otherwise. 
 
 For instance, take a going barrel spring of eight and a 
 half turns, breaking close up to the center while fully wound. 
 A 'point in the spring at the fracture makes eight turns in 
 the opposite direction to which it was wound, a point at the 
 middle four turns, and a point at the outer end nothing, an 
 effect similar to the whole mass of the spring making four 
 turns backwards. At its greatest velocity it is suddenly 
 stopped by the barrel, wheel teeth engaging its pinion; this 
 stoppage or collision is what breaks center pinions, third piv- 
 ots, wheel teeth, etc., unless their elasticity, or some inter- 
 posed contrivance, can safely absorb the stored-up energy 
 of the mainspring, the spring being, as every one knows, 
 the heaviest moving part in an ordinary clock, except where 
 the barrel is exceptionally massive. 
 
 Stop Works. — Stop works are devices that are but little 
 understood by the majority of workmen in the trade. They 
 are added to a movement for either one or both of two dis- 
 tinct purposes: First, as a safety device, to prevent injury 
 to the escape wheel from over winding, or to prevent undue 
 force coming on the pendulum by jamming the weight 
 against the top of the seat board and causing a variation in 
 time in a fine clock; or, second, to use as a compromise by 
 utilizing only the middle portion of a long and powerful 
 spring, which varies too much in the amount of its power 
 in the up and down positions to get a good rate on the 
 clock if all the force of the spring were utilized in driv- 
 ing the movement. 
 
 With weight clocks, the stop work is a safety device and 
 should always be set so that it will stop the winding when 
 the barrel is filled by the cord ; consequently the way to set 
 them is to wind until the barrel is barely full and set the 
 stops with the fingers locked so as to prevent any further 
 action of the arbor in the direction of the windincr and the 
 
THE MODERN CLOCK. 283 
 
 cord should then be long enough to permit the weight to be 
 free. Then unwind until within half a coil of the knot in 
 the cord where it is attached to the barrel and see that the 
 weight is also free at the bottom of the case, when the stops 
 again come into action. This will allow the full capacity 
 of the barrel to be used. 
 
 When stop work is found on a spring barrel, it may be 
 taken for granted that the barrel contains more spring than 
 is being wound and unwound in the operation of the clock 
 and it then becomes important to know how many coils are 
 thus held under tension, so that wc may put it back .cor- 
 rectly after cleaning. Wind up the spring and then let it 
 slowly down with the key until the stop work is locked, 
 counting the number of turns, and writing it down. Then 
 hold the spring with the letting down key and take a screw 
 driver and remove the stop from the plate ; then count the 
 number of turns until the spring is down and also write 
 that down. Then take out the spring and clean it. You 
 may find such a spring will give seventeen turns in the bar- 
 rel without the stop work on, while it will give but ten with 
 the stop work; also that the arbor turned four revolutions 
 after you removed the stop. Then the spring ran the clock 
 from the fourth to the fourteenth turns and there were 
 four coils unused around the arbor, ten to run the clock and 
 three unused at the outer end around the barrel. This 
 would indicate a short and light pendulum or balance, which 
 is very apt to be erratic under variations of power, and if 
 the rate was complained of by the customer you can look 
 for trouble unless the best adjustment of the spring is se- 
 cured. Put the spring back by winding the four turns and 
 putting on the stop work in the locked position ; then wind. 
 If the clock gains when up and loses when down, shift the 
 stop works half a turn backwards or forwards and note the 
 result, making changes of the stop until you have found 
 the point at which there is the least variation of power in 
 the up and down positions. If the variation is still too great 
 a thinner spring must be substituted. 
 
284 THE MODERN CLOCK. 
 
 There are several kinds of stop work, the most common 
 being what is known as the Geneva stop, a Maltese cross 
 and a finger such as is commonly seen on watches. For 
 watches they have five notches, but for clocks they are 
 made with a greater number of notches, according to the 
 number of turns desired for the arbor. The finger piece is 
 mounted on a square on the barrel arbor and the star wheel 
 on the stud on the plate. In setting them see that the finger 
 is in line with the center of the star wheel when the stop is 
 locked, or they will not work smoothly. 
 
 There is another kind of stop work which is used in some 
 American clocks, and as there is no friction with it, and no 
 fear of sticking, nor any doubt of the certainty of its action, 
 it is perhaps the most suitable for regulators and other fine 
 clocks which have many turns of the barrel in winding. 
 This stop is simple and sure. It consists of a pair of wheels 
 of any numbers with the ratio of odd numbers as 7 and 6, 
 9 and 10, 15 and 16, 30 and 32, 45 and 48, etc. ; the smaller 
 wheel is squared on the barrel arbor and the larger mounted 
 on a stud on the plate. These wheels are better if made 
 with a larger number of teeth. On each wheel a finger is 
 planted, projecting a little beyond the outsides of the wheel 
 teeth, so that when the fingers meet they will butt securely. 
 The meeting of these fingers cannot take place at every 
 revolution because of the difference in the numbers of the 
 teeth of the wheels ; they will pass without touching every 
 time till the cycle of turns is completed, as one wheel goes 
 round say sixteen times while the other goes fifteen, and 
 when this occurs the fingers will engage and so stop fur- 
 ther winding. When the clock has run down sixteen turns 
 of the barrel the fingers will . again meet on the opposite 
 side, and so the barrel will be allowed to turn backwards 
 and forwards for sixteen revolutions, being stopped by the 
 fingers at each extreme. When in action the fingers may 
 butt either at a right or an obtuse angle, only not too obtuse, 
 as this would put a strain on, tending to force the wheels 
 
THE MODERN CLOCK. 
 
 apart. If preferred the fingers may be made of steel, but 
 this is not necessary. 
 
 Maintaining Powers. — x\stronomical clocks, watch- 
 maker's regulators and tower clocks arc, or at least should 
 be, fitted with maintaining power. A good tower clock 
 should not vary in its rate more than five to ten seconds a 
 week. Many of them, when favorably situated and care- 
 fully tended, do not vary over five to ten seconds per month. 
 It requires from five to thirty minutes to wind the time 
 trains of these clocks and the reader can easily see where 
 
 Fig. 83 
 
 the rate would go if the power were removed from the pen- 
 dulum for that length of time ; hence a maintaining power 
 that will keep nearly the same pressure on the escape wheel 
 as the weight does, is a necessity. Astronomical clocks and 
 fine regulators have so little train friction, especially if jew- 
 eled, that when the barrel is turned backwards in winding 
 the friction between the barrel head and the gr^at wheel is 
 sufficient to stop the train, or even run it backwards, injur- 
 ing the escape wheel and, of course, destroying the rate of 
 the clock; therefore they are provided with a device that 
 will prevent such an occurrence. Ordinary clocks do not 
 have the maintaining power because only the barrel arbor 
 is reversed in winding, and that reversal is never for more 
 than half a turn at a time, as the power is thrown back on 
 the train every time the winder lets go of the key to turn 
 his hand over for another grip. 
 
286 
 
 THE MODERN CLOCK. 
 
 Figs. 83, 84 and 85 show the various forms of main- 
 taining powers, which differ only in their mechanical de- 
 tails. In all of them the maintaining power consists of two 
 ratchet wheels, two clicks and either one or two springs ; 
 the springs vary in shape according to whether the great 
 wheel is provided with spokes or left with a web. If the 
 great wheel has spokes the springs are attached on the out- 
 side of the large ratchet wheel so that they will press on 
 opposite spokes of the great wheel and are either straight, 
 curved or coiled, according to the taste of the maker of the 
 clock and the amount of room. If made with a web a cir- 
 
 Fig. 84 
 
 cular recess is cut in the great wheel, see Fig. 83, wide and 
 deep enough for a single coil of spring wire which has its 
 ends bent at right angles^ to the plane of the spring and one 
 end slipped in a hole of the ratchet and the other in a sim- 
 ilar hole in the recess of the great wheel. A circular slot 
 is cut at some portion of the recess in the great wheel 
 where it will not interfere with the spring and a screw in 
 the ratchet works back and forth in this slot, limiting the 
 action of the spring. Stops are also provided for the spokes 
 of the great wheel in the case of straight, curved or coiled 
 springs, Figs. 84 and 85. These stops are set so as to give 
 
THE MODERN CLOCK. 2S7 
 
 an angular movement of two or three teeth of the great 
 wheel in the case of tower clocks and from six to eight 
 teeth in a regulator. The springs should exert a pressure 
 on the great wheel of just a little less than the pull of the 
 weight on the barrel ; they will then be compressed all the 
 time the weight is in action, and the stops will then transmit 
 the power from the large ratchet to the great wheel, which 
 drives the train. Both the great wheel and the large rat- 
 chet wheel are loose on the arbor, being pinned close to the 
 barrel, but free to revolve. A smaller ratchet, having its 
 
 Fig. 85 
 
 teeth cut in the reverse direction from those of the larger 
 one, is fast to the end of the barrel. A click, called the 
 winding click, on the larger ratchet acts in the teeth of the 
 smaller one during the winding, holding the two ratchets 
 together at all other times. A longer click, called the de- 
 tent click, is pivoted to the clock plate, and drags idly over 
 the teeth of the larger ratchet while the clock is being 
 driven by the weight and the maintaining springs are com- 
 pressed. When the power is taken off by the reversal of 
 the barrel in winding, the friction between the sides of the 
 two ratchets and great wheel would cause them to also turn 
 backward, if it wevQ not for this detent click. W'ith its end 
 fast to the plate, which drops into the teeth of the large 
 ratchet and prevents it from turning backward. We now 
 have the large ratchet held motionless by the detent click 
 on the clock plate and the compressed springs which are 
 
288 
 
 THE MODERN CLOCK. 
 
 carried between the large ratchet and the great wheel will 
 then begin to expand, driving the loose great wheel until 
 their force has been expended, or until winding is com- 
 pleted, when they will again be compressed by the pull of 
 th-e weight. In some tower clocks curved pins are fixed to 
 opposite spokes of the great wheel and coiled springs are 
 wound around the pins. Fig. 85 ; eyes in the large ratchet 
 engage the outer ends of the pins and compress the springs. 
 The clicks for maintaining powers should not be short, 
 and the planting should be done so that lines drawn from 
 the barrel center to the click points and from the click cen- 
 ters to the points, will form an obtuse angle, like B, Fig. 86. 
 
 Fig. 
 
 giving a tendency for the ratchet tooth to draw the click 
 towards the barrel center. The clicks should be nicely 
 formed, hardened and tempered and polished all over with 
 emery. Long, thin springs will be needed to keep the wind- 
 ing clicks up to the ratchet teeth. The ratchet wheel must 
 run freely on the barrel arbor, being carried round by the 
 clicks while the clock is going, and standing still while the 
 weight is being wound up. It is retained at this time by a 
 long detent click mounted on an arbor having its pivots 
 fitted to holes in the clock frame. The same remark as to 
 planting applies to this click as well as the others, and to all 
 
THE MODERN CLOCK. 
 
 289 
 
 clicks having similar objects; but as this chck has its own 
 weight to cause it to fall no spring is required. To pre- 
 vent it lying heavily on the wheel, causing wear, friction 
 and a diminution of driving power, it is as well to have it 
 made light. There is no absolute utility in fixing the click 
 to its collet with screws, but if done, it can be taken off 
 to be polished, and the appearance will be more workman- 
 like. This click should have its point hardened and tem- 
 pered, as there is considerable wear on it. 
 
 If the great wheel has spokes the best form for the two 
 springs for keeping the train going whilst being wound 
 is that of the letter U, as shown to the left of Fig. 84, one 
 end enlarged for the screw and steady pin and the blade 
 tapering all along towards the end which is free. The 
 springs may be made straight and bent to the form while 
 
 n 
 
 Fig. 87 
 
 soft, then hardened and tempered to a full blue. They are 
 best when as large as the space between two arms of the 
 main wheel will allow. When screwed on the large ratchet 
 the backs of both should bear exactly against the respective 
 arms of the mainwheel, and a pair of pins is put in the 
 ratchet, so that any opposite pair of the mainwheel arms 
 may rest upon them when the springs are set up by the 
 clock weight. The strength of the springs can be ad- 
 justed by trial, reducing them till the weight of the clock 
 sets them up easily to the banking pins. 
 
 There are two methods of keeping the loose wheels 
 against the end of the barrel, while allowing them to turn 
 freely during winding ; one is a sliding plate with a keyhole 
 slot, Fig. 87, to slip in a groove on the arbor, as is generally 
 adopted in such house clocks as have fuzees, as well as on 
 
290 THE MODERN CLOCK. 
 
 the barrels of old-fashioned weight clocks; the other is a 
 collet exactly the same as on watch fuzees. They are both 
 sufficiently effective, but perhaps the latter is the best of the 
 two, because the collet may be fitted on the arbor with a 
 pipe, and being turned true on the broad inside face, gives 
 a larger and steadier surface for the mainwheel to work 
 against, whereas the former only has a small bearing on the 
 shoulder of the small groove in the arbor, which fitting is 
 Hable to wear and allow the main and the other loose wheel 
 to wobble sideways, displacing the contact with the detent 
 click and causing the mainwheel to touch the collet of the 
 center wheel if very near together ; so, on the whole, a col- 
 let, as on a watch fuzee, seems the better arrangement, 
 where there is plenty of room for it on the arbor. 
 
 There is an older form of maintaining power which is 
 sometimes met with in tower clocks and which is sometimes 
 imitated on a small scale by jewelers who are using a cheap 
 regulator and wish to add a maintaining power where there 
 is no room between the barrel and plates for the ratchets 
 and great wheel. 
 
 The maintaining power. Fig. 88, consists of a shaft. A, a 
 straight lever, B, a segment of a pinion, C, a curved, double 
 lever, D, a weight, E. The shaft, A, slides endwise to en- 
 gage the teeth of the pinion segment with the teeth of the 
 great wheel. No. 2, the straight lever has a handle at both 
 ends to assist in throwing the pinion out or in and a shield 
 at the outer end to cover the end of the winding shaft. No. 
 3, when the key is not on it. 
 
 The curved lever is double, and the pinion segment turns 
 loosely between the halves and on the shaft, A ; it is held 
 up in its place by a light spring, F; the weight, E, is also 
 held between the two halves of the double lever. 
 
 The action is as follows : The end of the lever, B, covers 
 the end of the winding shaft so that it is necessary to raise 
 it before putting the key on the winding shaft; it is raised 
 till it strikes a stop, and then pushed in till the pinion seg- 
 
THE MODERN CLOCK, 
 
 291 
 
 Fig. 88. Maintaining Power. 
 
292 THE MODERN CLOCK. 
 
 ment engages with the going wheel of the train, when the 
 weight, E, acting through the levers, furnishes power to 
 drive the clock-train while the going weight is being wound 
 up. Of course the weight on the maintaining power must 
 be so proportioned to the leverage that it will be equal to 
 the power of the going barrel and its weight, a simple prop- 
 osition in mechanics. 
 
 The number of teeth on the pinion segment, C, is suffi- 
 cient to maintain power for fifteen minutes, at the end of 
 which time the lever, B, will come down and again cover 
 the end of the winding shaft ; or, it may be pumped out of 
 gear and dropped down. In case it is forgotten, the spring, 
 F, will allow the segment to pass out of gear of itself and 
 will simply allow it to give a click as it slips over each 
 tooth in the going wheel ; if this were not provided for, it 
 would stop the clock. 
 
CHAPTER XVI. 
 
 MOTION WORK AND STRIKING TRAINS. 
 
 Motion work is the name given to the wheels and pinions 
 used to make the hour hand go once around the dial while 
 the minute hand goes twelve times. Here a few prelimi- 
 nary observations will do much toward clearing up the 
 operations of the trains. The reader will recollect that we 
 started at a fixed point in the time train, the center arbor 
 which must revolve once per hour, and increased this mo- 
 tion by making the larger wheels drive the smaller (pin- 
 ions) until we reached sixty or more revolutions of the 
 escape wheel to one of the center arbor. This gearing to 
 increase speed is called "gearing up" and in it the pinions 
 are always driven by the wheels. In the case of the hour 
 hand we have to obtain a slowing effect and we do so by 
 making the smaller wheels (pinions) drive the larger ones. 
 This is called "gearing back" and it is the only place in 
 the clock where this method of gearing occurs. 
 
 We drew attention to a common usage in the gearing up 
 of the time trains — ^that of making the relations of the 
 wheels and pinions 8 to one and 7.5 to one ; 7.5 X 8 = 60. 
 So we find a like usage in our motion work, viz., 3 to one 
 and 4 to one ; 3X4=12. Say the cannon pinion has 
 twelve teeth; then the minute wheel generally has 36, or 
 three to one, and if the minute wheel pinion has 10, the 
 hour wheel will have 40, or four to one. Of course, any 
 numbers of wheels and pinions may be used to obtain the 
 same result, so long as the teeth of the wheels multiplied 
 together give a product which is twelve times that of the 
 pinions multiplied together ; but three and four to one have 
 
 293 
 
294 "^^^ MODERN CLOCK. 
 
 been settled upon, just as the usage in the train became 
 fixed, and for the same reasons; that is, these proportions 
 take up the least room and may be made with the least 
 material. Also, the pinion with the greatest number of 
 teeth, being the larger, is usually selected as the cannon 
 pinion, as it gives more room to be bored out to receive the 
 cannon, oi* pipe. If placed outside the clock plate, the min- 
 ute wheel and pinion revolve on a stud in the clock plate: 
 but if placed between the frames, they are mounted on 
 arbors like the other w^heels. The method of mounting is 
 merely a matter of convenience in the arrangement of the 
 train and is varied according to the amount of room in the 
 movement, or convenience in assembling the movement at 
 the factory, little attention being paid to other considera- 
 tions. 
 
 o 
 
 fc 
 
 Fig. 89. Fig. 90. 
 
 The cannon pinion is loose on the center arbor and be- 
 hind it is a spring, called the center spring, or ''friction," 
 Figs. 89 and 90, which is a disc that is squared on the arbor 
 at its center and presses at three points on its outer edge 
 against the side of the cannon pinion; or it may be two or 
 three coils of brass wire. This center spring thus produces 
 friction enough on the cannon to drive it and the hour 
 hand, while permitting the hands to be turned backward or 
 forward without interfering with the train. In French man- 
 tel clocks the center spring is dispensed with and a portion 
 of the pipe is thinned and pressed in so as to produce k 
 
THE MODERN CLOCK. 
 
 295 
 
 friction between the pipe and the center arbor which is 
 sufficient to drive the hands ; this is similar to the friction 
 of the cannon pinion in a watch. 
 
 In some old English house clocks w^ith snail strike, the 
 cannon pinion and minute wheel have the same number of 
 teeth for convenience in letting off the striking work by 
 means of the minute wheel, which thus turns once in an 
 hour. Where this is the case the hour wheel and its pinion 
 
 
 ^^\ 
 7/N^- 
 
 
 I 
 
 Fig. 91. 
 
 bear a proportion to each other of twelve to one; usually 
 there is a pinion of six leaves engaging a wheel of ^2 teeth, 
 or seven and eighty-four are sometimes found. 
 
 In tower clocks, where the striking is not discharged by 
 the motion w'ork, the cannon pinion is tight on its arbor 
 and the motion work is similar to that of watches. See 
 Fig. 91. 
 
 The cannon pinion drives the minute wheel, which, to- 
 gether with its pinion, revolves loosely on a stud in the 
 
296 THE MODERN CLOCK. 
 
 clock plate, or on an arbor between the frames. The mesh- 
 ing of the minute wheel and cannon pinion should be as 
 deep as is consistent with perfect freedom, as should also 
 that of the hour wheel and minute pinion in order to prevent 
 the hour hand from having too much shake, as the minute 
 wheel and pinion are loose on the stud and the hour wheel 
 is loose on the cannon, so that a shallow depthing here will 
 give considerable back lash, which is especially noticeable 
 when winding. 
 
 The hour wheel has a short pipe and runs loosely on the 
 cannon pinion in ordinary clocks. In quarter strike cuckoos 
 a different train is employed and the wheels for the hands 
 are both on a long stud in the plate and both have pipes; 
 the minute wheel has 32 teeth and carries four pins on its 
 under side to let off the quarters. The hour wheel has 64 
 teeth and works close to the minute wheel, its pipe sur- 
 rounding the minute wheel pipe, and held in position by a 
 screw and nut on the minute pipe. A wheel of 48 and a 
 pinion of 8 teeth are mounted on the sprocket arbor with a 
 center spring for a friction, the wheel of 48 meshing with 
 the minute wheel of 32 and the 8-leaf pinion with the hour 
 wheel of 64. It will be recollected that the sprocket wheel 
 takes the place of the barrel in this clock and there is no 
 center arbor as it is commonly understood. The sprocket 
 arbor in this case turns once in an hour and a half, hence it 
 requires 48 teeth to drive the minute wheel of ^^ once in 
 an hour, as it turns one-third of a revolution (or 16 teeth) 
 every half hour. The sprocket arbor, turning once in an 
 hour and a half, makes eight revolutions in twelve hours and 
 its pinion of eight leaves working in the hour wheel of 64 
 teeth turns the hour hand once in twelve hours. 
 
 In ordinary rack and snail striking work the snail is gen- 
 erally mounted on the pipe of the hour wheel, so that it will 
 always agree with the position of the hour hand and the 
 striking will thus be in harmony with the position of the 
 hands. 
 
THE MODERN CLOCK. 297 
 
 Striking Trains. — It is only natural, after finding cer- 
 tain fixed relations in the calculations of time trains and 
 motion work, that we should look for a similar point in 
 striking trains, well assured that we shall find it here also. 
 It is evident that the clock must strike the sum of the num- 
 bers 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, II, 12, or 78 blows of the 
 hammer, in striking from noon to midnight; this will be 
 repeated from midnight to noon, making 156 blows in 24 
 hours, and if it is a 30-hour clock, six hours more must be 
 added; blows for these will be 21 more, making a total of 
 177 blows of the hammier for a 30-hour strike train. The 
 hammer is raised by pins set in the edge of a wheel, called 
 the pin wheel, and as one pin must pass the hammer tail 
 for every blow, it is evident that the number of pins in this 
 wheel will govern the number of revolutions it must, make 
 for 177 blows, so that here is the base or starting point in 
 our striking train. If there are 13 pins in the pin wheel, 
 it must revolve 13.5 times for 177 blows ; if there are 8 pins, 
 then the wheel must revolve 22.125 times in giving 177 
 blows; consequently the pinions and wheels back to the 
 spring or barrel must be arranged to give the proper num- 
 ber of revolutions of the pin wheel with a reasonable num- 
 ber of turns of the spring or weight cord, and it is gen- 
 erally desirable to give the same, or nearly the same, num- 
 ber of turns to both time and striking barrels. 
 
 If it is an eight-day clock the calculation is a little differ- 
 ent. There are 156 blows every 24 hours; then as the ma- 
 jority of "eight-day" clocks are realiy calculated to keep 
 time for seven and a half days, although they will run 
 eight, we have : 156 X 7-5 = 1,070 blows in 7.5 days. With 
 13 pins we have 1,070 -f- 13 = 80 and 4-i3ths revolutions 
 in the 7.5 days. If now we put an 8-leaf pinion on the pin 
 wheel arbor and 84 teeth in the great wheel or barrel, we 
 will get 10.5 turns of the pin wheel for every turn of the 
 spring or barrel ; consequently eight turns of the spring will 
 
298 THE MODERN CLOCK. 
 
 be enough to run the clock for the required time, as such 
 clocks are wound every seventh day. 
 
 Figuring forward from the pin wheel, we find that we 
 shall have to lock our striking train after a stated number 
 of blows of the hammer -each hour; these periods increase 
 by regular steps of one blow every hour, so that we must 
 have our locking mechanism in position to act after the 
 passage of each pin, whether it is then used or not ; so the 
 pinion that meshes with the pin wheel, and carries the lock- 
 ing plate or pin on its arbor must make one revolution every 
 time it passes a pin. If this is a 6-leaf pinion, the pins on 
 the pin wheel must therefore be 6 teeth apart; or an 8-leaf 
 pinion must have the pins 8 teeth apart; and vice versa. 
 For greater convenience in registering, the pins are set in 
 a radial line with the spaces of the teeth in the pin wheel, 
 as this allows us to measure from the center of the pinion 
 leaf. 
 
 It will thus be seen that the calculation of an hour striking 
 train is a simple matter; but if half hours are also to be 
 struck from the train, it will change these calculations. 
 For a 30-hour train 24 must be added to the 156 blows for 
 24 hours, 180 blows being required to strike hours and half 
 hours for 24 hours. These blows may be provided for by 
 more turns of the spring, or different numbers of the wheels 
 and pinions, which would then also vary the spacing of the 
 pins. 
 
 Half hours may also be struck directly from the center 
 arbor, by putting an extra hammer tail on the hammer 
 arbor, further back, where it will not interfere with the 
 hammer tail for the pin wheel, and putting a cam on the 
 center arbor to operate this second hammer tail. This 
 simplifies the train, as it enables the use of a shorter spring 
 or smaller wheels while providing a cheap and certain 
 means of striking the half hours. Half-hour trains are 
 frequently provided with a separate bell of different tone for 
 the half hours, as with only one bell the clock strikes one 
 
THE MODERN CLOCK. 
 
 299 
 
 Fig. 92. Eight Day Hour and Half Hour Strike. 
 
300 THE MODERN CLOCK. 
 
 blow at 12 .-30, I and 1 130, making the time a matter of 
 doubt to one who Hstens without looking, as frequently 
 happens in the night. 
 
 Fig. 92 shows an eight-day, Seth Thomas movement, 
 which strikes the hours on a count wheel train and the half 
 hours from the center arbor. All the wheels, pinions, ar- 
 bors, pins, levers and hooks are correctly shown in proper 
 position, but the front plate has been left off for greater 
 clearness. The reader will therefore be required to remem- 
 ber that the escape wheel, pallets, crutch, pendulum and the 
 stud for the pendulum suspension are really fixed to the 
 front plate, while in the drawing they have no visible 
 means of support, because the plate is left off. 
 
 The time train occupies the right-hand side of the move- 
 ment and the striking train the left-hand. Running up the 
 right hand from the spring to the escape wheel, we find an 
 extra wheel and pinion which is provided to secure the 
 eight days' run. We also see that what would ordinarily 
 be the center arbor is up in the right corner and does not 
 carry the hands; further, the train is bent over at a right 
 angle, in order to save space and get the escape wheel in 
 the center at the top of the movement. The striking train 
 is also crowded down out of a straight line, the locking 
 cam being to the right of the pin wheel and the warning 
 wheel and fly as close to the center as possible. This leaves 
 some space between the pin wheel and the intermediate 
 wheel of the time train and here we find our center arbor, 
 driven from the intermediate wheel by an extra pinion on 
 the minute wheel arbor, the minute wheel meshing with 
 the cannon pinion on the center arbor. This rearranging 
 of trains to save space is frequently done and often shows 
 considerable ingenuity and skill ; it also will many times 
 serve to identify the maker of a movement when its origin 
 is a matter of doubt and we need some material, so that 
 the planting of trains is not only a matter of interest, but 
 
THE MODERN CLOCK. 3OI 
 
 should be studied, as familiarity with the methods of vari- 
 ous factories is frequently of service to the watchmaker. 
 
 Fig. 93 is the upper portion of the same striking train, 
 drawn to a larger scale for the sake of clearness. It also 
 shows the center arbor, both hammer tails and the stop on 
 the hammer arbor, which strikes against the bottom of the 
 front plate to prevent the hammer spring from throwing the 
 hammer out of reach of the pins. The pin wheel, R, and 
 count wheel, E, are mounted close together and are about 
 the same size, so that they are shown broken away for a 
 part of their circumferences for greater clearness in ex- 
 plaining the action of the locking hook, 'C, and the locking 
 cam, D. 
 
 Fig. 94 shows the same - parts in the striking position, 
 being shown as just about to strike the last blow of 12. 
 Similar parts have similar letters in both figures. 
 
 The count wheel, E, is loose on a stud in the Dlatc, con- 
 centric with the arbor of the pin wheel, R. The pivot of R 
 runs through this stud. The sole office of the count wheel 
 is to regulate the distance to which the locking hook C, is 
 allowed to fall. The count hook, A, and the locking hook, 
 C, are mounted on the same arbor, B, so that they move in 
 unison. If A is allowed to fall into a deep slot of the count 
 wheel, C will fall far enough to engage the locking face of 
 the cam D and stop the train, as in Fig. 93. If, on the 
 contrary, A drops on the rim of the wheel, C will be held 
 out of the locking position as D comes around (see Fig. 
 94), and the train will keep on running. It will be seen 
 that after passing the locking notch, D, Fig. 94, will in its 
 turn raise the hook C, which will ride on the edge of D, 
 and hold A clear of the count wheel until the locking notch 
 of D is again reached, when a deep notch in the wheel will 
 allow C to catch, as in Fig. 93, unless C is stopped by A 
 falHng on the rim of the wheel, as in Fig. 94. 
 
 One leaf, F, of the pinion of the locking arbor sticks out 
 far enough to engage with the count wheel teeth and rotate 
 
302 
 
 THE MODERN CLOCK. 
 
 Fig. 93. Upper Portion of Striking Train Locked. 
 
THE MODERN CLOCK. 
 
 303 
 
 Fig. 94. Striking Train Unlocked and Running. 
 
3^4 
 
 illK IvIODEIlN CJ.OCK. 
 
 the wheel one tooth for each revolution of D, so that F 
 forms a one-leaf pmion similar to that of a rack striking' 
 train. Here we have our counting mechanism ; F and D 
 go around together ; F moves E one tooth every revolution. 
 A holds C out of action (Fig. 94) until A reaches a deep 
 slot, when C stops the train by engaging D (Fig. 93). 
 
 The count wheel, E, must have friction enough on its 
 stud so that it will stay where the pin F leaves it, -when F 
 goes out of action and thus it will be in the right "position ta 
 suitably engage F on the next revolution. Too much fric- 
 tion of the count wheel on its stud will use too much power 
 for F to move it and thus slow the train; if there is too little 
 friction here the count wheel may get in such a position 
 that F will get stalled on the top of a tooth and stop the 
 train. 
 
 The count hook, A, must strike exactly in the middle of 
 the deep slots, without touching the sides of the slots in 
 entering or leaving, as to do this would shift the position of 
 the count wheel if the rubbing were sufficient, or it might 
 prevent A from falling (as A and C are both very light) 
 and the clock would go on striking. If the hook A does not 
 strike the middle of the spaces between the teeth of the 
 count wheel, it will gradually encroach on a tooth and push 
 the wheel forward or back, thus disarranging the count. 
 Many a clock has struck 13 for 12 in this way because the 
 hook was a little out. This did not occur in the smaller 
 numbers because the action w^as not continued long enough 
 to allow the hook to reach a tooth. The pin, F, should also 
 mesh fairly and freely in the teeth of the count wheel, or 
 a similar defect is likely to occur. 
 
 When repairing or making new count hooks, A, Figs. 
 93 and 94, ihey must be of such a length that they will enter 
 the slots on a line radial with the center of the wheel. The 
 proper length and direction are shown at A, Fig. 95, while 
 B and C are wrong. With hooks like either B or C you 
 can set or bend the hook to strike right at one and as you 
 
IIE MOl^EKN CLOCK. 
 
 305 
 
 turn the clock ahead the hook does not fall in far enough 
 and at twelve it only strikes eleven. Then if you bend the 
 same hook to strike right at twelve it will strike two at one 
 and as you turn the clock ahead it will strike right at about 
 five or seven. A, Fig. 95, being of the proper length and shape 
 will give no trouble. ■ Many of-the count wheels of the older 
 clocks w^ere divided by hand and are not as accurate as 
 they should be ; when a wheel of this kind is found and a 
 new'- w^heel cannot be substituted (because the clock is an 
 
 Fig. 95, The proper length of the count hook. 
 
 antique and must have the original parts preserved) it will 
 sometimes require nice management of the hook A to obtain 
 correc striking. A little manipulation of the pinion, F, 
 Fig 93 is sometimes desirable also, if the count wheel is 
 very bad. 
 
 . The locking face of the cam, D, must also be on a line 
 radial to its center, or it will either unlock too easily and 
 go off on the slightest jar or movement of the clock, or the 
 face will have too much draw and the hook C will not be 
 unlocked when the clock is fully wound, and the spring 
 pressure is greatest. In this case the clock will not strike 
 when fully wound, but will do so when partly run down, 
 
306 THE MODERN CLOCK. 
 
 and as the count wheel train strikes in rotation, without re- 
 gard to the position of the hands, you will have irregular 
 striking of a most puzzling sort. Repairs to this notch are 
 sometimes required, when the corner has become rounded, 
 and the best way to make them is to cut a new face on the 
 cam with a sharp graver, being careful to keep the face 
 radial with its center. 
 
 Because the count wheel strikes the hours in rotation, 
 regardless of the position of the hands, if the hands are 
 turned backwards past the figure 12 on the dial the striking 
 will be thrown out of harmony with the hands. To remedy 
 this the count hook. A, has an eye on its rear end and a 
 wire, shown in Fig. 92, hangs down to where it can be 
 reached with the hand when the dial is on. Pulling this 
 wire will lift A and C and cause the clock to strike ; by this 
 means the clock may be struck around until the position of 
 the striking train agrees with that of the hands. Where 
 this wire is not present the striking is corrected by turning 
 the hands back and forth between IX and XII until the 
 proper hour is struck. 
 
 Now we come to the releasing mechanism, which causes 
 the clock to strike at stated times. I, Figs. 93 and 94, is an 
 arbor pivoted between the plates and carrying three levers, 
 H, K and J, in different positions on the arbor. H is directly 
 under the count hook, A, and lifts A and C whenever J is 
 pushed far enough to one side by L on the center arbor, 
 which revolves once an hour. Thus L, through J, H and 
 A, C, unlocks the train once every hour. When C is thus 
 lifted the train runs until the warning pin, O, Figs. 93 and 
 94, strikes against the lever K, which is on the same arbor 
 with H and J. This preliminary run of the train makes a 
 little noise and is called "warning," as the noise notifies 
 us that the train is in position to commence striking. The 
 lever K and the warning pin, O, then hold the train until 
 L has been carried out of action with J and released it, when 
 
THE MODERN CLOCK. 307 
 
 O will push K out of its path at every revolution and the 
 clock will strike. 
 
 The half hours are struck by L^ pressing the short ham- 
 mer tail, G\ and thus raising and releasing the hammer once 
 an hour. 
 
 In setting up the striking train after cleaning, place the 
 pin wheel so that the hammer tail, G, may be about one- 
 fourth of the distance from the next pin, as shown in Fig. 
 93 ; this allows the train to get well under way before meet- 
 ing with any resistance and will insure its striking when 
 nearly run down. If the hammer tail is too close to the pin, 
 it might stop the train when there is but little power on. 
 
 Then place D in the locked position, wath A in a deep 
 slot of the count wheel and C in the notch of D. Next 
 place the warning wheel with its pin, O, on the opposite side 
 of its arbor from the lever K, see Fig. 93. This is* done to 
 make sure that when it is unlocked for "warning" the train 
 will run far enough to get the corner of the lock, D, safely 
 past C, so that it will not allow C to fall into the notch again 
 and lock the train when J, K and H are released by L. This 
 is the rule followed in assembling these clocks at the fac- 
 tories and is simple, correct and easily understood. A study 
 of these points in Fig. 93. will enable any one to set up a 
 train correctly before putting the front plate on. 
 
 If the workman gets a clock that has been butchered by 
 some one who did not understand it (and there are many 
 such), he may find that when correctly set up the clock 
 does not strike on the 60th minute of the hour ; in such a 
 case a little bending of J, in or out as the case may be, will 
 usually remedy the trouble. The same thing may have to 
 be done to the hammer tails, G and G^, or the stop on the 
 hammer arbor. If both hammer tails are out of position, 
 bend the stop; if one is right, let the stop alone and bend 
 the other tail. 
 
 A rough, set or gummy spring will cause irregular stri- 
 king. In such a case the clock will strike part of the blows 
 
308 THE MODERN CLOCK. 
 
 and then stop and finally go on again and complete the 
 number. Much time has been lost in examining the teeth 
 of wheels and pinions in such cases when the trouble lay 
 in the spring. Too strong a spring will make the move- 
 ment strike too fast; too weak a spring will make it strike 
 slow, especially in the latter part of the day or week, when 
 it has nearly run down. 
 
 Too small a fan, or a fan that is loose on its arbor, will 
 allow the clock to strike too fast. If this fan is badly out 
 of balance it will prevent the train from starting when 
 there is but little power on. 
 
 There is a class of clocks which have the count wheel 
 tight on the arbor, outside the clock plate. Many of them 
 are on much tighter than they should be. In such a case 
 take an alcohol lamp and heat the wheel evenly, especially 
 around the hub; the brass will expand twice as much as 
 the steel and the wheel may then be driven off without 
 injury. 
 
 Fig. 96 shows another typical American eight-day train, 
 made by the Gilbert Clock Company, and striking the half 
 hours from the train. Here we notice, on comparing with 
 Fig. 92, that there are many points of difference. First 
 the notches on the count wheel, are twice as wide as they 
 are in Fig. 92. This means that half hours are struck on 
 the train; this will be explained later. Next there are two 
 complete sets of notches on the wheel, which shows that 
 the wheel turns only once in twenty-four hours, whereas 
 the other makes two revolutions in that time. There are 
 no teeth on the count wheel, so that it must be fast to its 
 arbor, which is that of the great wheel and spring, while 
 Fig. 92 has a separate stud and it is loose. The wheel being 
 on the spring arbor and going once in 24 hours, there must 
 be one turn of spring for each 24 hours which the train 
 runs. There is no pin wheel in Fig. 96, but instead of this 
 two pins are cut out of the locking cam to raise the hammer 
 tail as they pass. There are also two locking notches in 
 
THE MODERN CLOCK. 
 
 309 
 
 Fig. 96. Half hours struck on the train. 
 
3IO THE MODERN CLOCK. 
 
 the locking cam. The cams on the center arbor are stamped 
 out of brass sheet, while those of Fig. 92 were of wire. 
 
 Turning to the enlarged view in Fig. 97 and comparing 
 it' with Fig. 93, we find further differences. The levers 
 K and J are here made of one piece of brass, while the 
 others were separate and of wire. The lifting lever, H, is 
 flattened at its outer end in Fig. 93, while in Fig. 97 it is 
 bent at right angles and passed under the count hook, A. 
 The hook, C, Fig. 97, is added to the arbor, B, as a safety 
 device, in case the locking hook should fail to enter its slot 
 in the cam, D. It is shown as having just stopped the warn- 
 ing pin in Fig. 96. There is but one hammer tail, G, and 
 the hammer stop acts against the stud for the hammer 
 spring, instead of against the bottom of the front plate, as 
 in Fig. 92. 
 
 The first important difference here is in the position of 
 the count hook, A. In Figs. 92 and 93 the hook must be 
 exactly in the middle of the slot, or there will be trouble. 
 In trains striking half hours from the train, we must never 
 allow the hook to occupy the middle of the slot, or we will 
 have more trouble than we ever dreamed of. In this in- 
 stance the count hook must enter the slot close to (but not 
 touching) the side of the slot when the clock stops striking; 
 then when the half hour is struck the count wheel will 
 move a little and the hook must drop back into the same 
 slot without touching; this brings it close to the opposite 
 side of the same slot and the next movement will land the 
 hook safely on top of the wheel for the strokes of the hour. 
 Fig. 96 shows its position after striking the half hour and 
 ready to strike the hour of two. Fig. 97 shows it dropping 
 back after striking two. 
 
 In setting up this train, see that the count hook, A, goes 
 into the slot of the count wheel close to, but not touching, 
 one side of the slot in the count wheel, and, after placing 
 the intermediate, insert the locking cam, D, so that it en- 
 gages the locking hook; then put in the warning wheel 
 
THE MODERN CLOCK. 
 
 31^ 
 
 Fig. 97 . Half hour strike on the count wheel. 
 
312 THE :modern clock. 
 
 with the warning pin, O, safely to the left of the hook C, 
 Fig. 97, so that it cannot get past that hook after striking. 
 Placing the wheel with its warning pin six or eight teeth 
 to' the left of the edge of the bottom plate is generally about 
 right. The action of the levers, H, J, K, the hammer tail, 
 G, and the cam, L, in striking the hours is the same as that 
 already described in detail for Figs. 93 and 94, hence need 
 not be repeated here. L^ strikes the half hours by being 
 enough shorter than L to raise the hooks for one revolution, 
 but not quite so high as for the hours. The cams L, L^ are 
 friction tight on the center arbor and may be shifted on the 
 arbor to register the striking on the 60th minute, if desired. 
 When the hands and strike do not agree, turn the minute 
 hand back and forward between IX and XII, thus striking 
 the clock around until it agrees with the hands. 
 
 Sometimes, if the warning pin is not far enough away, 
 an eight-day clock will strike all right for a number of days 
 and then commence to gain or lose on the striking side. It 
 either does not strike at some hours, or half hours, or it 
 may strike sometimes both hour and half hour before stop- 
 ping. Take the movement out of the case and put the hands 
 on; then move the minute hand around slowly until the 
 clock warns. Look carefully and be sure there is no dan- 
 ger of the clock striking when it warns. If this looks secure, 
 then move the hand to the hour, making it strike; say it is 
 going to strike 9 o'clock; when it has struck eight times, 
 stop the train with your finger and let the wheels run very 
 slow while striking the last one, and when the rod drops 
 into the last notch stop the train again and hold it there. 
 
 For the striking part to be correct, the warning pin on 
 the wheel wants to be about one-fourth of a revolution 
 away from the rod when the clock has struck the last timxC, 
 or as soon as this rod falls down far enough to catch the 
 pin. The object of this is so there is no chance of the 
 warning pin getting past the rod at the last stroke; this it 
 is liable to do if the pin is too close to the rod when the 
 
THE MODERN CLOCK. 313 
 
 rod drops. If you will examine the clock as above, not only 
 when it strikes IX, but all the hours from I to XII, you will 
 generally find the fault. Of course, if the pin is too close 
 to the rod when the rod drops, you must lift the plates apart 
 and change the wheel so that the warning pin and the rod 
 will be as explained. 
 
 Ship's Bell Striking Work. — Of all the count wheel 
 striking work which comes to the watchmaker, the ship's 
 bell is most apt to give him trouble. This generally arises 
 from ignorance as to what the system of bells on shipboard 
 consists of and how they should be struck. If he goes to 
 some nautical friend, he hears of long and short ''watches" 
 or "full watches" and "dog watches." If he insists on de- 
 tails, he gets the information that a "watch" is not a horo- 
 logical mechanism, but a period of duty for a part of the 
 crew. Then he is told of the "morning watch," "first dog 
 w^atch," "afternoon watch," "second dog watch," "off 
 watch," "on watch," etc. Now the ship's bell clock does 
 not agree with these "watches" and was never intended to 
 do so. As a matter of fact, it is simply a clock striking 
 half hours from one to eight and then repeating through 
 the twenty-four hours. 
 
 The striking is peculiarly timed and is an imitation of 
 the method in which the hours are struck on the bell of 
 the ship. As this bell is also used for other purposes, such 
 as tolling in fogs, fire alarms, church services, etc., it will 
 readily be seen that a different method of striking for each 
 purpose is desirable to avoid misunderstanding of signals. 
 
 The method of striking for time is to give the blows in 
 couples, with a short interval between the strokes of the 
 couples and three times that interval between the couples. 
 Odd strokes are treated as a portion of the next couple and 
 separated accordingly, thus: 
 
314 THE MODERN CLOCK. 
 
 Fig. 98. Ships bell clock. 
 
THE MODERN CLOCK. 315 
 
 12:30 p. m. One Bell, O 
 
 I :oo p. m. Two Bells, O O 
 
 I :30 p. m. Three Bells, O O 
 
 2:00 p. m. Four Bells, O O 
 
 2:30 p. m. Five Bells, O O 
 
 3 :oo p. m. Six Bells, O O 
 
 3 :30 p. m. Seven Bells, O O 
 
 4:00 p. m. Eight Bells, O O 
 
 After striking eight bells the clock repeats, although the 
 ship's bell is generally struck in accordance with the two 
 dog watches (which are of two hours' duration each) be- 
 fore commencing the evening watch (8 to 12 p. m.). It 
 will thus be seen that the clock should strike eight at 12 m., 
 4 p. m., 8 p. m., 12 p. m., 4 a. m,, and 8 a. m. 
 
 In order to strike the blows in pairs two hammers are 
 necessary, see Fig. 98; these hammers are placed close to- 
 gether, but not in the same plane. The pin wheel has twenty 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 t, ,T T I 1, I T »',T I 1, I f'.T T, i;T-I T T 
 
 I' r' 'I ■ I • 'I LxJ "LlJI 
 
 Fig. 100. The pins on the count wheel of the ships bell clock. 
 
 pins, see Figs. 98, 99, 100; some of these pins are shorter 
 than the others, so that they do not operate one of the ham- 
 mer tails. These are shown graphically in Fig. 100 ; where 
 the two oblong marks at figure i represent the tops of the 
 hammer tails shown in Fig. 99. It will be seen by studying 
 Fig. 100 that with the wheel moving from left to right, the 
 inside hammer tail will be operated for one blow, while the 
 
3i6 
 
 THE MODERN CI.OCK, 
 
 Fig. 99. Enlarged view of striking work, ships bell clock. 
 
TlIK MODERN CLOCK. 317 
 
 outer hammer tail will not De operated at all, thus giving 
 but one blow, or "bell." At the next movement of the pin 
 wheel, the outside hammer will be operated by the long pin 
 and the inside hammer by the short pin, thus giving one 
 blow of each hammer, or "two bells." 
 
 We now have these hammer tails advanced along the 
 wheel so that the outside one is opposite the figure 3 in the 
 drawing, while the other is opposite the figure 2, with one 
 pin between them. The next movement of the pin wheel 
 advances them so that the outside hammer will pass the 
 next short pin and consequently that hammer will miss one 
 blow and the pair will therefore strike three — one by the 
 outside hammer and two by the inside. It thus goes on 
 until the cycle is completed, eight blows being struck with 
 the last four pins. The striking in pairs is effected by 
 having the two hammer tails close together, so that the 
 pins will operate both hammer tails quickly and there will 
 then be an interval of time while the wheel brings forward 
 the next pins. This is so spaced that the interval between 
 pairs is three times that between the blows of a pair and 
 the hammer tails should not be bent out of this position, or 
 if found so they should immediately be restored to it. Toll- 
 ing the bells, instead of striking them properly, is very bad 
 form at sea and generally leads to punishment if persisted 
 in, so that the jeweler will readily perceive that his marine 
 customers are very particular on this point, and he should 
 go any length to obtain the proper intervals in striking. 
 
 The pin wheel moves forward one pin for each couple 
 of blows or parts of a couple, the odd blows being secured 
 by the failure of the blow w^hen the hammer tail passes the 
 short pin. Thus it moves as far for one bell as for two 
 bells; as far for three bells as for four, etc. The result is 
 that the count wheel has no odd numbers on it, but instead 
 two 2's, two 4's, two 6's and tw^o 8's ; the first two are 
 counted on the count wheel, but only one is struck on the 
 pin wheel, owing to the short pin ; this is repeated at three, 
 
3l8 THE MODERN CLOCK. 
 
 five and seven, when four, six and eight are counted on 
 the wheel, but the last blow fails of delivery, owing to the 
 short pin in the pin wheel at these positions. 
 
 The center arbor carries two pins, L and L^, to unlock 
 the train through the lever J, as it is really a half-hour- 
 striking clock. The count hook, A ; locking hook, C ; count 
 wheel, E; pins, P, and other parts have similar letters for 
 similar parts as in the preceding figures and need not be 
 further explained, as the mechanism is otherwise similar 
 to the Seth Thomas movement shown in Fig. 92. 
 
CHAPTER XVIL 
 
 CLEANING AND REPAIRING CUCKOO CLOCKS. 
 
 The cuckoos are in a class by themselves for several rea- 
 sons, all of which have to do with their construction and 
 should therefore be understood by the watchmaker. They 
 are bought as timepieces by but two classes of people : those 
 who were used to them in their former homes in Europe 
 and buy them for sentimental reasons; and those who ad- 
 mire fine wood carvings as works of art and desire to pos- 
 sess a finely carved cuckoo clock for the reasons which 
 govern in the purchase of paintings and statuary, bronzes, 
 and other art objects. For this reason cuckoos have never 
 been a success when attempts have been made to cheapen 
 their production by the use of imitations of wood carving in 
 composition or metal. The use of cuckoos in plain cases, 
 with springs instead of weights, has also been attempted 
 with the idea of thereby securing an inclosed movement, 
 as in ordinary clocks; but while it offers advantages in 
 cleanliness and protection of the movement, such clocks have 
 never become popular, as they have lost their character as 
 works of art by being enclosed in plain cases, or have be- 
 come rather erratic in rate by the substitution of springs 
 for weights. 
 
 The use of exposed weights and pendulum necessitates 
 openings in the bottom of the case through which the dust 
 enters freely and this makes necessary unusual side shake, 
 end shake and freedom of depthing of the wheels and pin- 
 ions and also the use of lantern pinions and an amount of 
 driving weight in excess of that necessary for protected 
 movements, as there must be enough weight to pull the 
 
 319 
 
320 THE MODERN CLOCK. 
 
 cuckoo movement through obstructions which would stop 
 the ordinary movement. 
 
 Repairers therefore should not attempt to close worn 
 holes as snugly as in the ordinary movements, as when this 
 is done the clock generally stops about three weeks after it 
 has left the shop and a "comeback" is the result. Lighten- 
 ing the driving weights will have the same result, as the 
 movement must have sufficient power to pull it through 
 when dirty. As the plates and wheels are generally of cast 
 metal, cutting of pivots from running dry is frequent in 
 old clocks, and where it is necessary to close the holes care 
 must be taken not to overdo it. 
 
 Another point where repairers fail is in not polishing the 
 pivots. Many watchmakers seem to think that any kind 
 of a pivot will do for a clock, although they take great care 
 of them in their watchwork. Rough and dry pivots will 
 cut the holes in a clock plate deep enough to wedge the 
 pivots in the holes like a stuck reamer and stop a clock 
 just after it has been repaired, when if they had been prop- 
 erly polished the job would not have come back. 
 
 The high prices of wood carving in America and the 
 necessity for its genuineness, as explained above, has re- 
 sulted in making it necessary to spend as little as possible 
 for the movements ; hence we ordinarily find a total lack of 
 finish on the movements, and this, with the great freedom 
 everywhere evident in its construction and the apparent 
 excess of angular motion of the levers, combine to give it 
 an appearance of roughness which surprises those who see 
 them but rarely. 
 
 It has been frequently suggested by watchmakers that if 
 the cases only were imported and the movements were made 
 by the American factories better results should be obtained, 
 in appearance at least. They forget that the bellows, pipes 
 and birds, with their wires, are parts of the movements 
 and the cost of having these portions made in this country 
 is prohibitive, so that the whole movement is imported. 
 
THE MODEIiN CLOCK. 32 1 
 
 Arrangements are now being made by at least one firm to 
 have the frames and wheels made of sheet metal by auto- 
 matic machinery, instead of being cast and finished in the 
 usual way, and when this is done the appearance of the 
 movements will be greatly improved, so that American 
 watchmakers will regard them with a more kindly eye. 
 So far as is known to the writer all cuckoo movements are 
 im.ported, although one firm is doing a large and constantly 
 growing trade in such clocks with cases made in America. 
 
 There are a number of importing firms who sell to job- 
 bers, large retailers and clock companies only, and as the 
 large American clock manufacturers all list and carry 
 cuckoos the clocks find their way to the consumer through 
 many and devious channels. Probably more are sold in 
 other ways than through the retailers for the reason that 
 the average retailer does not understand the cuckoos and 
 is reluctant to stock them, thereby deliberately avoiding a 
 large amount of business from which he might make a 
 haiidsome profit. 
 
 Under the general term Cuckoos are listed several kinds 
 of movements, all having bellows, pipes and moving fig- 
 ures, such as the cuckoo, cuckoo and quail, trumpeter, etc., 
 with or without the regular hammers and gongs of the ordi- 
 nary movements. 
 
 Figs. TOi and 102 show front and back views of a tmie 
 train in the center with quail strike train on the left and 
 cuckoo strike train at the right. The positions of arbors, 
 levers, depthings of trains, etc., are exact, but the m.ove- 
 ment plates have been left off for greater clearness, so that 
 the arbors appear to be without support. The positions of 
 the pillars are shown by the shaded circles above and below 
 the trains in Fig. loi. The parts have the same letters in 
 both Figs. ]Ci and 102, althoigh as the movement is turned 
 around to show the rear in 102, the quail train appears on 
 the right side. 
 
322 
 
 THE MODERN CLOCK. 
 
 Fig. 101. Front View of Quail and Cuckoo Strike Movement. 
 
THE MODEJiX CLOCK. 
 
 NAMES OF PARTS. 
 
 3- 
 
 A— Quail count wheel. O— Quail Lifting pin wheel. 
 
 B— Quail striking cam. P— Cuckoo lifting lever. 
 
 C— r^liuute wheel. Q— Cuckoo warning lever. 
 
 D— Quail lifting lever. R— Cuckoo lifting pin. 
 
 E— Quail count hook. S— Cuckoo locking arm. 
 
 F— Quail locking arm. T— Cuckoo count hook. 
 
 G— Quail bird stick; U— Cuckoo striking cam. 
 
 alpo called bird holder. V— Cuckoo lifting pin wheel. 
 
 H— Quail bellows arm. W— Cuckoo count wlieel. 
 I— Quail bellows lifting lever. X— Cuckoo bellows lifting lever. 
 
 J— Quail gong hammer. Y — Cuckoo hnnimcr. 
 
 K— Quail warning lever. Z— Cuckoo biid stick; 
 L,— Quail lifting pin. also called bird holder. 
 
 M— Quail bird stick lever. S^— Cuckoo bird stick lever. 
 iS — Quail hammer lever. 
 
 In examining a movement the student discovers a peculi- 
 arity of cuckoo frames, which is that the pivot holes for 
 several of the arbors of the striking levers have slots filed 
 into them, reaching to the edges of the frames and nar- 
 rower than the full diameter of the pivot holes. This is 
 because such arbors have levers riveted into them which 
 must function in front, between and at the rear of the plates 
 and in setting up the movem.ent the. slots are necessary to 
 allow^ the end levers to pass through the holes. Such arbors 
 as have slots on the front plates are inserted and placed in 
 their proper positions before setting the train wheels wdth 
 which they function. The others are first inserted in the 
 back plate and turned to position while putting on that 
 plate. 
 
 Both quail and cuckoo trains are set up very simply and 
 surely by observing the following points : In the quail 
 train, when the quail bellows lever, H, is just released from 
 a pin in the pin wdieel, O, the locking lever, F, must just 
 fall into the slot of the locking cam, B; the warning pin 
 should then be near the fly pinion and the count hook, K, 
 drop freely into the count wheel, A. 
 
 On the cuckoo side we find two levers, X ; the upper one 
 of these operates the low note of the cuckoo call and the 
 lower one the high note. When this upper lever is released 
 
324 
 
 THE MODERN CLOCK. 
 
 Fig. 102. Rear View of Quail and Cuckoo Movement. 
 
THE MODERN CLOCK. 
 
 3-5 
 
 from a pin in the pin wheel, the cuckoo locking lever, S. 
 must drop into its locking cam, U, and the count hook, T, 
 drop into its count wheel, while the warning pin must be 
 near the fly pinion. After the run has stopped and the 
 trains are fully locked the warning pins will be as shown 
 in Fig. 102; but at the moment of locking they should be 
 as described above. 
 
 The operation is as follows: Turning to Fig. loi, we 
 find the minute wheel, C. has four pins projecting from its 
 rear surface. This revolves once per hour and conse- 
 quently the pins raise the lifting lever, D, every fifteen 
 minutes. Here is a point that frequently is productive of 
 trouble. The reader will readily see that if the hands of 
 a cuckoo are turned backv/ard the pins in the minute wheel 
 w^ill bend this wire, D, and derange the striking, as the 
 warning lever is also attached to the same arbor. Never 
 push the hands baekzvard on a cuckoo clock ; ahvays push 
 them forward. If the striking and hands do not register 
 the same time, take off the weights of the striking trains ; 
 then push the hands forward until they register the hour 
 which the trains struck last. As there is no power on the 
 trains they wdll not be operated, the only action being the 
 rising and falling of the lever, D, as the pins pass. When 
 the hands point to the hour last struck by the trains, put 
 on the striking weights again and push the hands forzi'ard, 
 allowing time for each striking, until the clock has been 
 set to the correct time. 
 
 Upon the lifting lever, D, being raised sufficiently the 
 warning lever, E, on the same arbor is lifted into the path 
 of the warning pin and at the same time unlocks the train 
 by pressing against the lifting pin, L, in the locking lever, 
 F. The locking lever, F, count hook, K, and the bird 
 holder lever, M, are all on the same arbor and therefore 
 work in unison. When D drops, E releases the warning 
 pin and the train starts. The pin wdicel has pins on both 
 sides, the rear pins operate the gong hammer, N, J ; the 
 
2--" TJIE ISIODERN CI.OCK. 
 
 front pins operate the quail bellows, I, H. The rising, and 
 falling of the unlocking lever, F, operates the bird holder, 
 G, through M and the wire in the bellows top tilts the tail 
 of the bird and flutters the wings. When the fourth quarter 
 has been struck, the pins shown in the quail count wheel, 
 A, operate the hour hfting lever, P, and the action of that 
 train becomes similar to that of the quarter train just de- 
 scribed, with the difference that there are two bellows 
 levers, X, for the high and low notes of the cuckoo, whereas 
 there is but one for the quail. 
 
 There are several adjustments necessary to watch on 
 these clocks. The wires to operate the bellows from the 
 levers X and H may be so long that the bellows when 
 stretched to its full capacity may not allow the tails of X 
 and H to clear the pins of the pin wheels and thus stop 
 the trains. The pins should clear safely w:th the bellows 
 fully opened. The levers M and S', which operate .he 
 bird holders, G and Z, may be turned in their arbors so as 
 to be farther from or closer to the bird holder; this regu- 
 lates the opening and closing of the doors and the appear- 
 ance of the birds ; if there is too much movement the birds 
 may be sent so far out that they will not return, but will 
 stay out and stop the trains. Moving S' and M towards 
 the bird holders, Z and G, will lessen the amount of this 
 motion and the contrary movement will increase it. 
 
 Another important source of trouble — because generally 
 unsuspected — is the fly. The fly on a cuckoo train must 
 be tight ; a loose fly will cause too rapid striking and allow 
 tlic train to overrun, making wrong striking, or in a very 
 bad. case it will not stop until run down. When this hap- 
 pens turn your attention to the fly and make sure that it is 
 tight before doing any bending of the levers, and also see 
 to the position of the warning pin. 
 
 Sometimes the front of the case (which is also the dial) 
 will warp and cause pressure on the ends of the lever ar- 
 
THE MODERN CLOCK. 
 
 3-7 
 
 bors and thus interfere with their proper working. Be 
 sure that the arbors are free at both ends. 
 
 When replacing worn pins in the striking trains, care 
 should be taken to get them the right length, as on account 
 of the large amount of end shake in these movements they 
 may slip past the levers w^ithout operation, if too short, or 
 foul the other parts of the train if too long. For the same 
 reasons bending the levers should only be done after ex- 
 hausting the other sources of error and then be undertaken 
 very slowly and cautiously. 
 
 The notes of a cuckoo are A and F, jirst belov/ middle C ; 
 these should be sounded clearly and with considerable vol- 
 ume. If they are short and husky in tone it may be due 
 to holes in the bellow^s, too short stroke of bellows, removal 
 of the bellows weights, E, Fig. 103, dirt in the orifices of the 
 pipes, or cracks in the pipes. Holes in the bellows, if small 
 and not in the folds of the kid, may be m.ended by being 
 glued up with paper or kid, or a piece of court plaster 
 which is thin enough to not interfere wi'di the operation of 
 the bellow^s. If much worn a new bellow^s should be sub- 
 stituted. Cracks in the pipes may be mended with paper. 
 
 The orifice of the pipe, if dirty, may be cleaned with a 
 piece of mainspring filed very thin and smooth and care- 
 fully inserted, as any widening or roughening of this slit 
 w^ill interfere with the tone. Sometimes a clock comes in 
 v;hich has been spoiled in this regard, then it beconies nee 
 essary to remove the outer portion or lip. A, Fig. 1 03, of 
 the slot (which is glued in position) and make a new inner 
 lip, B, or file the old one smooth again. The proper shape 
 is shown in B, Fig. 103, while C and D show improper 
 shapes which interfere with the tone. 
 
 ]\Iuch time and money has been spent in trying to avoid 
 the inherent defects of this portion of the clock; sometimes 
 the lips will swell or warp and close the orifice; sometimes 
 they wdll shrink and make it too wide ; in either case a loss 
 of purity of tone is the result. Brass tubes, if thm enougn 
 
328 
 
 THE MODERN CLOCK, 
 
 Fir:. 193. Cuckoo bellows and pipe. A, outer lip; B, inner lip; C, D, 
 incorrect forms of lip. 
 
THE MODERN CLOCK. 329 
 
 to be cheap, give a brassy tone to the notes ; compositions 
 of lead, tin and antimony (organ pipe metal) are readily 
 cast, but give a softer, duller tone of less volume than the 
 wood. Celluloid lips to a wooden tube were at first thought 
 to be a great success, but were found to warp as they got 
 older. Bone lips are costly ; so there is nothing at present 
 that seems likely to displace well seasoned wood, where 
 discriminating lovers of music and art demand purity and 
 correctness of tone, reasonably accurate time, artistic sculp- 
 tural effects and durability, all in one article — a high class 
 cuckoo clock. 
 
 When sending a clock home after repairing, each of the 
 chains should be tied together with strings just outside the 
 bottom of the case so that they will not slip off the sprockets 
 and the customer should be instructed to hang the clock 
 in its accustomed position before cutting the strings and 
 attaching the weights. 
 
CHAPTER XVIII. 
 
 SNAIL STRIKING WORK, ENGLISH, FRENCH AND AMERICAN. 
 
 While the majority of snail striking movements made in 
 America are on the French system, because they are cheaper 
 when made in that way, still this system is so condensed 
 and so difficult to illustrate, with all its mechanism packed 
 in a small space between the plates, that the , student will 
 gain a much better idea of the rack and snail and its prin- 
 ciples by first making a study of an English snail striking 
 clock, which has the whole of the counting and releasing 
 levers placed outside the front plate, where they can occupy 
 all the room that may be necessary. The calculation and 
 planting of the striking train do not differ from those using 
 the count wheel, up to and including the single toothed 
 pinion or gathering pallet. The stopping of the train after 
 striking is different and the counting is divided, being de- 
 pendent upon four pieces acting in conjunction in an hour 
 strike of the simplest order, which number may run to a 
 dozen in a repeating clock. 
 
 As the count wheel system had the defect of getting out 
 of harmony with the hands when the latter are turned back- 
 ward, so the snail system has its defects, which are the dis-. 
 placement of the rack and failure to stop the striking in 
 some clocks if the striking train runs down before the time 
 side and is then rewound, and a most puzzling inaccuracy 
 of counting, resulting from slight wear and inaccuracy of 
 adjustment. We mention these things here because they 
 have an influence on the construction of the clock and an 
 advance knowledge of them will serve to make clearer some 
 of the statements which follow. 
 
 330 
 
THE MODERN CLOCK. 33I 
 
 Hour and Half-Hour Snail Striking Work. — Fig. 
 104 is a view of the front plate of an English fusee strik- 
 ing clock, on the rack principle. The going train occupies 
 the right and center and the striking train the left hand. 
 The position of the trains is indicated in dotted lines, the 
 trains having barrels and fusees as shown by the squared 
 arbors, all the dotted work being between the clock plates, 
 and that in full lines being placed on the outside of the 
 front plate, under the dial. The connection between the 
 going train and the striking w^ork is by means of the motion 
 w^ieel on the center arbor, and connection is made between 
 the striking train and the counting work by the gathering 
 pallet, F, wdiich is fixed to the arbor of the last wheel but 
 one of the striking train, and also by the warning piece, 
 which is shown in black on the boss of the lifting piece, A. 
 This w^arning piece goes through a slotted hole in the plate, 
 and during the interval between warning and striking stands 
 in the path of a warning pin in the last wheel of the striking 
 train. The motion wheel on the center arbor, turning once 
 in an hour, gears with the minute wheel, E, which has an 
 equal number of teeth. There are tw^o pins opposite each 
 other and equidistant from the center of the minute wheel, 
 which in passing raise the lifting piece, A, every half hour. 
 Except for a few minutes before the clock strikes, the strik- 
 ing train is kept from running by the tail of the gathering 
 pallet. F, resting on a pin in the rack, C. Just before the 
 hour, as the boss of the lifting piece, A, lifts the rack hook 
 B, the rack C, impelled by a spring in its tail, falls back 
 until the pin in the lower arm of the rack is stopped by the 
 snail, D. This occurs before the lifting piece, A, is released 
 by the pin in the minute wheel, E, and in this position the 
 warning piece stops the train. Exactly at the hour the pin 
 in the minute wheel, E, gets past the lifting piece, A, wdiich 
 then falls, and the train is free. For every blow struck by 
 the hammer the gathering pallet, F, which is really a one- 
 toothed pinion, gathers up one tooth of the rack, C, which 
 
332 THE MODERN CLOCK. 
 
 is then held, tooth by tooth, by the point of the hook, B. 
 After the pinion, F, has gathered up the last tooth, its tail is 
 caught by the pin in the rack, which stops and locks the 
 tram, and the striking ceases. 
 
 The snail, O, is mounted on a twelve-toothed star wheel, 
 placed on a stud in the plate, so that a pin in the motion 
 wheel on the center arbor moves it one tooth for each revo- 
 lution of the motion wheel, and it is then held in position by 
 the click and spring as shown. The pin, in moving the star 
 wheel, presses back the click, which not only keeps the 
 star wheel steady, but also completes its forward motion 
 after the pin has pushed the tooth past the projecting center 
 of the click. The steps of the snail are arranged so that at 
 one o'clock it permits only sufficient fall of the rack for one 
 tooth to be gathered up, and at every succeeding hour gives 
 the rack an additional motion equal to one extra tooth. It 
 will be seen that where a star wheel is used a cord or wire 
 attached to A and run outside the case, so that A may be 
 lilted, will cause the clock to repeat the hour whenever 
 desired. 
 
 The lower arm of the rack, C, and the lower arm of the 
 lifting piece. A, are made of brass, and thin, so as to yield 
 when the hands of the clock are turned back ; the lower 
 extremity of the lifting piece. A, is a little wider, and bent 
 to a slight angle with the plane of the arm, so as not to butt 
 as it comes into contact with the pin when this is being 
 done. If the clock is not required to repeat, the snail may 
 be placed upon the center arbor, instead of on a stud with 
 a star wheel as shown, and this is generally done with the 
 che::per class of hour striking clocks ; but the position of the 
 snail is not then so definite, owing to the backlash of the 
 motion wheels, so that it will not repeat correctly, as the 
 pin of the rack m,ay fall on a slope of the snail and, besides, 
 a smaller snail must be used, unless it is brought out to 
 clear the nose of the minute wheel cock, or bridge if one 
 be used. 
 
THE MODERN CLOCK. 
 
 333 
 
 ..^^^P^^^^ 
 
 Fig. 104. Hour and half hour snail striking work "with fusee train. 
 
334 
 
 THE MODERN CLOCK. 
 
 Half-Hour Striking. — The usual way of getting the 
 clock to strike one at the half-hour, is by making the first 
 tooth of the rack, C, lower than the rest, and placing the 
 second pin in the minute wheel, E, a little nearer the center 
 than the hour pin, so that the rack hook, B, is lifted free 
 of the first tooth only at the half hour. But this adjustment 
 is too delicate after some wear has occurred and the action 
 is then liable to fail altogether or to strike the full hour, 
 from the pin getting bent or from uneven wear of the parts. 
 The arrangement shown in Fig. 104 is generally used in 
 English work, as it is much safer. One arm of a bell crank 
 lever rests on a cam fixed to the minute wheel, E. This 
 arm is shaped so that just before the half-hour the other ex- 
 tremity of the bell crank lever catches a pin placed in the 
 rack, C, and permits it to release the train and fall the dis- 
 tance of but one tooth. This is the position shown in Fig. 
 104. After the half-hour has struck, the cam carries the 
 hook free from the pin in C. 
 
 Division of the Hour Snail.— The length of the rack 
 tail, from the center of the stud hole in the rack to the 
 center of the pin, should be equal to the distance between 
 the center of the stud hole and the center of the snail. The 
 difference between the radius of the top and the radius of 
 the bottom step of the snail may be obtained by getting the 
 angular distance of twelve teeth of the rack from center to 
 pin. See A B, CD, E F, Fig. 105, which show the total 
 distances for twelve steps of the snail for rack tails of 
 different lengths. Divide the circumference of a piece of 
 brass into twelve parts and draw radial lines as shown in 
 Fig. 106. Each of these spaces is devoted to a step of the 
 snail. Draw circles representing the top and bottom step. 
 Divide the distance, A B or E F, Fig. 105, between these 
 two circles, into eleven equal parts, and at each division 
 draw a circle which will represent a step of the snail. The 
 rise from one step to another should be sloped as shown, so 
 as to raise the pin in the rack arm if the striking train has 
 
THE MODERN CLOCK. 
 
 335 
 
 been allowed to run down, and it should be resting on the 
 snail when it is desired to turn the hands back. The rise 
 from the bottom to the top step is bevelled off, so as to push 
 the pin in the rack arm on one side, by springing the thin 
 brass of the arm and allow it to ride over the snail if it is 
 in the way when the clock is going. It should also be 
 curved to avoid interference with the pin. Clockmakers 
 making new snails when repairing generally mark off the 
 
 Fig. 105. Rack, showing method of getting sizes of snail steps accord- 
 ing to distance from the rack center to the pin in the rack tail. 
 
 snail on the clock itself after the rest of the striking work 
 is in position. A steel pointer is fixed in the hole of the 
 lower rack arm, and the star wheel jumped forward twelve 
 teeth (one at a time) by means of the pin in the motion 
 wheel. After each jump a line is marked on the blank 
 snail with the pointer in the rack arm by moving the rack 
 arm. These twelve lines correspond to the twelve radial 
 lines in Fig. io6. The motion wheel is then turned suffi- 
 ciently to carry the pin in it free of the star wheel and 
 leave the star wheel and blank snail quite free on their stud. 
 The rack hook is placed in the first tooth of the rack, and 
 v^hile the pointer in the rack arm is pressed on the blank 
 snail, the latter is rotated a little, so that a curve is traced 
 on it. The rack hook is then placed in the second, and after- 
 
336 THE MODERN CLOCK. 
 
 wards in the succeeding teeth consecutively, and the opera- 
 tion repeated till the twelve curves are marked. There is 
 one advantage in marking off the snail in this way. Should 
 there be any inaccuracy in the division of the teeth of the 
 rack, the steps of the snail are thus varied to suit it. This 
 frequently occurs in old clocks which have had new racks 
 filed up by hand by some watchmaker. 
 
 Reference to the drawing. Fig. 105, will show that the 
 rack is laid out as a segment of a wheel with teeth occupy- 
 ing two degrees each, with a few teeth added for safety. 
 Fourteen to sixteen teeth are generally provided, for the 
 following reasons : If the first tooth is used to strike the 
 half hours, it may in time become worn so that it can no 
 longer be stretched to its proper length. In such cases 
 moving the pin two degrees nearer the rack teeth will allow 
 us to use the teeth from the second to the thirteenth in 
 striking twelve, which makes a cheap and easy repair, as 
 compared to inserting a new tooth or making a new rack. 
 
 Weight driven snail clocks should have the weight cords 
 of the striking side long enough so that the striking train 
 will not run down before the time train, as in such a case 
 the rack tail is pushed to one side by the progress of the 
 snail (which is carried on the time train and is still run- 
 ning) ; then the rack will drop clear out of reach of the 
 gathering pallet and when the striking train is wound that 
 train will continue striking until it runs down, or the dial 
 is removed and the rack replaced in mesh with the gather- 
 ing pallet. This happens with short racks and with large, 
 old-fashioned snails. By leaving a few more teeth in the 
 rack the rack tail will strike the stud, or hour wheel sleeve, 
 before the rack teeth get out of reach of the gathering 
 pallet. 
 
 Many watchmakers put a stud or pin in the plate to stop 
 the rack from falling beyond the twelfth step, to prevent 
 troubles of this kind. 
 
THE MODERN CLOCK. 
 
 337 
 
 The rack tail is friction-tight on its arbor and should be 
 adjusted so that the proper tooth shall come in mesh with 
 the gathering pallet for each step of the snail, or irregular 
 striking will result. Such a clock may strike one, two, three 
 and four correctly and then strike six for five, or seven or 
 nine for eight, or thirteen for twelve, or it may strike one 
 or two hours wrong and the rest correctly. This is be- 
 cause the gathering pallet, F, Fig. 104, does not carry the 
 
 rack teeth safely past the edge of the rack hook, B, owing 
 to the tail of the rack not being properly adjusted. The 
 teeth should all be carried safely past the edge of the hook 
 and then be dropped back a little as the hook engages ; this 
 is the more necessary to watch with hand-made racks and 
 snails, or after putting in a new, and therefore larger, pin 
 in the rack tail to replace one which is badly worn. 
 
 The snail should be put on so that the pin in the rack 
 tail will strike the center of each step, or there is danger of 
 irregular striking, or of failure to strike twelve, owing to 
 the pin striking the surface of the cam midway between 
 one and twelve and thus preventing the rack from falling 
 
33^ THE MODERN CLOCK. 
 
 the requisite number of teeth. When this occurs the clock 
 will jam and stop. 
 
 The rack hook, B, Fig. 104, should be lifted far enough 
 so that the rack will fall clear of the hook without the teeth 
 catching and making a rattling noise as they pass the hook. 
 In many old hour strikes the first tooth of the rack is left 
 longer than the rest to ensure this freedom of passage 
 when the rack is released. 
 
 The gathering pallet, F, is the weakest member of the 
 system and will be very Hkely to be split or worn out in 
 clocks brought in for repair. It should be squared on its 
 arbor, or pinned, but many are not. If split, and the arbor is 
 round, where the pallet is put on, it may cause irregular 
 striking by opening on the arbor and permitting the train 
 to run when the tail strikes the pin in the rack. A new one 
 should be made so as to lift one tooth and a very little of 
 the next one at each revolution. It is necessary to cause 
 the gathering pallet to lift a little more than one tooth of the 
 rack, and let it fall back again, to insure that one will always 
 be lifted; because if such was not the case the clock would 
 strike irregularly, and would also be liable sometimes to 
 strike on continually till it ran down. If the striking part is 
 locked by the tail of the gathering pallet catching on a pin 
 in the rack, the tail should be of a shape that will best pre- 
 vent the rack from falling back when the clock wcirns for 
 striking the next hour ; and of course the acting faces of the 
 pallet must be perfectly smooth and polished. 
 
 The teeth of the rack may require dressing up in some 
 cases and to allow this to be done the rack may be stretched 
 a little at the stem, with a smooth-faced hamm.er, on a 
 smooth anvil ; or, if it wants much stretching, take the 
 pene of the hammer and strike on the back, with the -front 
 lying on the smooth anvil. The point of the rack hook, B, 
 will probably be much worn, and when dressing it up it 
 will be safe to keep to the original shape or angle. The 
 point of the rack hook is always broader than the rack, and 
 
THE MODERN CLOCK. 339 
 
 the mark worn in it will be about the middle of the thick- 
 ness ; so enough will be left to show what the original shape 
 or angle was. 
 
 After cleaning, particularly if it be French, look for dots 
 on the rims of the wheels, and for pinions with one end 
 of one leaf filed ofif slantingly. When putting it together, 
 place the pin wheel (that is the one with the pins) and the 
 pinion it engages with so that the leaf of the pinion (which 
 you will find filed slanting at one extremity) enters be- 
 tween the two teeth of the wheel, opposite which you will 
 find a countersunk mark, on the side of the wheel. See also 
 that the gathering pallet, F, w^hich lifts the rack, does so 
 ■at the same time that the gong hammer falls. Then place 
 the hour and minute wheels and cannon pinion so that the 
 countersunk marks on each line with each other. Neglect 
 of the marks on a marked train generally means that you 
 will have to take the clock down again and set it up prop- 
 erly before it will run ; therefore pay attention to these 
 marks the first time. 
 
 Quarter Chiming Snail Strikes. — Fig. 107 shows the 
 counting mechanism and trains of an English, fusee, quar- 
 ter-strike work. The time train occupies the center, the 
 hour striking train the left and the chiming train the right. 
 All the train wheels are between the plates and are dotted 
 in as in Fig. 104, while the counting mechanism is on the 
 front plate, behind the dial and is drawn in full lines, to 
 show that it is outside. 
 
 GOING TRAIN. 
 
 Fusee Wheel 96 
 
 Pinion 8 
 
 Center Wheel 84 
 
 Pinion 7 
 
 Tliird Wheel 78 
 
 Pinion 7 
 
340 THE MODERN CLOCK. 
 
 STRIKING TRAIN. 
 
 Fusee Wheel 84 
 
 Pinion 8 
 
 Pin Wheel, 8 pins in Pin Wheel 64 
 
 Pinion 8 
 
 Pallet Wheel 70 
 
 Pinion 7 
 
 Warning Wheel 60 
 
 Fly Pinion 7 
 
 CHIMING TRAIN. 
 
 Fusee Wheel 100 
 
 Pinion 8 
 
 Second Wheel 80 
 
 Pinion 8 • 
 
 Pallet Wheel ' 64 
 
 Pinion 8 
 
 Chiming Wheel 40 
 
 Warning Wheel 50 
 
 Fly Pinion 8 
 
 The reader will see a marked resemblance between the 
 hour and time trains of Fig. 104 and the same trains of 
 Fig. 107. The hour rack hook in 107, however, is hung 
 from the center and the hour warning lever is raised by a 
 spring instead of a Hfting piece. 
 
 The minute wheel of Fig. 107 carries a snail of four 
 steps, corresponding to the four teeth of the quarter rack, 
 and the tail of the quarter rack is bent upwards towards the 
 rack, to engage with the quarter snail. The quarter rack 
 carries a pin which projects on both sides of the rack; one 
 side of this pin stops the tail of the quarter gathering pallet 
 and therefore locks the train as fully described in Fig. 104. 
 The other side of the same pin acts on the tail of the hour 
 warning lever, so that whenever the quarter rack falls the 
 hour warning lever is released and its spring moves it into 
 the path of the hour warning pin. This goes on whether 
 the hour rack hook is released or not. Behind the quarter 
 snail, there are four pins in the minute wheel ; these pins 
 
THE MODERN CLOCK. 
 
 341 
 
 Fig. 107. Quarter chiming snail strike, Englisli fusee movement. 
 
342 
 
 THE MODERN CLOCK. 
 
 raise the quarter lifting piece, which raises the quarter 
 rack hook and the quarter warning lever at the same time, 
 thus warning and dropping the quarter rack; as soon as 
 the lifting piece drops, the warning lever and rack hook 
 are released and the quarter train starts. 
 
 Fig. 108. Eight day snail half hour strike, French system, striking 
 train locked. 
 
 One, two, three, or four quarters are chimed according 
 to the position of the quarter snail, wdiich turns with the 
 minute wheel. At the time for striking the hour (when 
 the quarter rack is allowed to fall its greatest distance), the 
 pin in it falls against the bent arm of the hour rack hook, 
 and releases the hour rack and hour w^arning lever. As the 
 last tooth of the quarter rack is gathered up, the pin in the 
 quarter rack pulls over the hour warning lever, and lets off 
 
THE MODERN CLOCK. 343 
 
 the hour striking train. The position of the pieces in the 
 drawing is as they would be directly after the hour was 
 struck. 
 
 Figs. 108, 109 and no arc three views of the New 
 Haven eight-day snail strike, which is on the French sys- 
 tem. As nearly all American strikes utilize this system and 
 the work is between the plates, this may be considered a 
 typical American snail strike. 
 
 As will be seen in Fig. io8, by the two pins at the center 
 arbor, immediately behind the snail, this is a half-hour 
 strike ; and as the rack hook has for its lower step a little 
 more than twice the depth of the other steps in the snail, it 
 will readily be perceived that this rack hook may be 
 pushed almost out and thus release the train without drop- 
 ping the rack. This is the method pursued in striking half 
 hours. 
 
 Figs. 109 and no show the parts more clearly than in 
 108. They are drawn a little larger than actual size and 
 wc will discover that the rack is the only portion of this 
 system that vrorks by gravity, all the others being spring 
 operated. Wc sec here the pins J K, which are used to 
 push out the lever M sufficiently far so that the upper 
 portion, which is bent at right angles to form a stop, will 
 free the warning pin O and allow the train to run. The 
 rack hook and the locking lever L are mounted on the same 
 arbor and are kept in position by a coiled spring on the 
 arbor until they are pushed out by the lower projection 
 at the upper end of M for either the half-hour or hour 
 strike. 
 
 As shown in Fig. 109, the lever M and the rack hook are 
 pushed out by J far enough to pass the warning pin O and 
 to unlock the train, which is normally locked by the pin N 
 and the lever L. G is the gathering pallet, which is a long 
 pin in a lantern pinion as in the ordinary count wheel strike. 
 H is the hammer tail and P the pin wheel ; R is the rack and 
 T the rack tail. The rack arm is curved to pass the center 
 
344 THE MODERN CLOCK, 
 
 arbor when dropping for twelve and the rack tail is bent 
 toward the teeth in order that it may admit of a longer rack 
 in a small movement, thus permitting of a large snail 
 and consequently less liability of disarrangement. The 
 same necessity of the proper adjustment of the rack tail T 
 with the snail exists as has already been spoken of in regard 
 to the English form of the snail strike. 
 
 In Fig. no will be seen the rack dropped clear with the 
 tail resting clear of the snail at one stroke from the snail. 
 In other words, the train is now in position to give eleven 
 more strokes, having struck the first stroke of twelve. By 
 comparison with Fig. 109, it will be seen that the spring 
 actuated arm M has been thrown forward so that its doc: is 
 resting on the center arbor, after having been released from 
 the hour pin K. This holds M out of the way of the w^arn- 
 ing pin O and the rack hook and allows the parts to oper- 
 ate as fully described with the English rack. 
 
 The gathering pallet G must have as many teeth as there 
 are teeth between the pins in the pin wheel P. The train 
 is locked by L coming in contact with X, the locking pin 
 on the wheel on the same arbor as the gathering pallet. In 
 setting this train up. it should stop so that the warning pin 
 O should be near the fly. 
 
 As all the parts are operated by springs on the arbor, as 
 shown by the hammicr spring II, it wi.l be seen that this 
 strike mechanism will wcrk in any position, while that 
 w^hich is operated by gravity must be kept upright. A 
 loose fly will cause the clock to strike too fast and may 
 cause it to strike wrong. Careless adjustment of the rack 
 tail T with the snail will also induce wrong counting, 
 although this is somewhat easier to adjust than the English 
 form of strike. The hock should safely clear the rack 
 teeth just as the gathering pallet G lets go of a tooth. If 
 attention is paid to this point in adjusting the rack tail 
 there will generally be little trouble. 
 
THE MODERX CLOCK. 
 
 3^5 
 
 The cam bearing the pins J K on the center arbor may be 
 shifted with a pair of pliers to secure accurate register of 
 hands and strike, as is the case with most American strikes. 
 In putting in the pin wheel it should be set so that the pins 
 may have a little run be fere striking the hammer tail, as 
 
 Fig. 109. Train about to strike the half hour; the hook 1/ free of the 
 train, which is held by the warning pin O ; one stroke will be given 
 when M drops. 
 
 this hammer tail is very short, and if the spring is strong 
 the pins may not be able to lift the hammer tail without 
 sufficient run to get the train thoroughly under motion. 
 The half-hour strike should also be tested so that the pin J 
 will release the warning pin O from the lever M without 
 releasing the rack hook from the rack, as shown in Fig. 
 
346 
 
 THE MODERN CLOCK. 
 
 109. The parts of the train when at rest will be readily 
 discerned in Fig. 108, where the hook L has locked the 
 train by the pin N and the freedom between the pins and 
 the hammer tail is about what it should be. 
 
 Fig. 110. Train unloclted and running. Xote position of L and M. 
 
 The relative position of the locking lever L and the rack 
 hook is also very clearly shown in Fig. 108; that is, when 
 the rack hook is pressed clear home at the lower notch of 
 the rack, the lever L should safely lock the train and the 
 lever M be resting with its link against the center arbor. 
 
CHAPTER XIX. 
 
 THE CONSTRUCTION OF SIMPLE AND PERPETUAL CALENDARS. 
 
 In taking up the study of calendar work the first thing 
 that the student observes is the irregularity of motion of 
 the various members. Every other portion of a clock has 
 for its main object the attainment of the nicest regularity 
 of motion, while the calendar must necessarily have irreg- 
 ular motion. The hand of the day of the month proceeds 
 around its dial regularly from i to 28 and then jumps t^ 
 I in February of some years, while it continues to 29 iii 
 others; sometimes it revolves regularly from I to 31 for 
 several revolutions and then jumps from 30 to i. What is 
 the reason of this? 
 
 If the moon's phases are shown they do not agree with 
 the changes of the month wheels, but keep gaining on them, 
 while if an "equation of time" is shown, we have a hand 
 that moves irregularly back and forth from the Figure XII 
 at the center of its dial. What is the cause of this gaining 
 and losing? 
 
 In order to understand this mechanism properly we shall 
 have to first know what it is intended to show and this 
 brings us to the study of the various kinds of calendar. 
 
 The earth revolves about its axis with a circular motion; 
 it revolves about the sun with an elliptical motion. This 
 means that the earth will move through a greater angular 
 distance, measured from the sun's center, in a given time at 
 some portions of its journey than it will do at others; at 
 times the sun describes an arc of 57 minutes of the ecliptic ; 
 at other times an arc of 61 minutes in a day; hence the sun 
 will be directly over a given meridian of the earth (noon) 
 
 347 
 
348 THE MODERN CLOCK. 
 
 a little sooner at some periods than at others. Now the 
 time at which the sun is directly over the given meridian is 
 apparent noon, or solar noon. As before stated, this is ir- 
 regular, while the motion of our clocks is regular, conse- 
 quently the sun crosses the meridian a little before or a 
 little after twelve by the clock each day, varying from 15 
 minutes before twelve to 15 minutes after twelve by the 
 clock. The best we can do under these circumstances is to 
 divide these differences of gaining or losing, take the aver- 
 age or mean of them and regulate the clock to keep mean 
 time. Here then we have two times — the irregular appar- 
 ent time and the regular mean apparent time. The amount 
 to be added to or subtracted from the mean in order to get 
 the solar or actual apparent time is called the equation of 
 time and this is shown by the equation hand on an astro- 
 nomical or perpetual calendar clock. 
 
 The moon revolves on its axis with a circular motion and 
 it revolves about the earth with an elliptical motion, the 
 earth being at one focus of the ellipse ; as this course does 
 not agree with that of the sun, but is shorter, it keeps gain- 
 ing so that the lunar months do not agree with the solar. 
 
 Certain stars are so far away that they apparently have 
 no m.otion of their own and are called iixed; hence in ob- 
 serving them the only motion we can discern is the circular 
 m^oticn of the earth. We can set our clocks by watching 
 such stars and a complete revolution of the earth, measured 
 by such a star, is called an asfronomieal or siderial 'day. 
 This is the one used in computing all our time. It is shorter 
 than the mean solar .day by 3 minutes 56 seconds. 
 
 A year is defined as the period of one complete revolu- 
 tion of the earth about the sun, returning to the same start- 
 ing point in the heavens. By taking different starting 
 points we are led to different kinds of years. The point 
 generally taken is the vernal equinoctial point, and when 
 measured thus it is called the tropical year, which gives us 
 the seasons. It is 20 mjnutes shorter than the siderial year. 
 
THE MODERN CLOCK. 349 
 
 A siderial year is the period of a complete revolution 
 of the earth about the sun. This period is very approxi- 
 mately 365 days, 6 hours, 9 minutes, 9.5 seconds of mean 
 time. Here we see an important difference between the 
 siderial and 'the cio'il year of 365 days, and it is this dif- 
 ference, which must be accounted for someliow, that causes 
 the irregularities in our calendar work. 
 
 For ordinary and business purposes the public demands 
 that the year shall contain an exact number of days and 
 that it should bear a simple relation to the recurrence of the 
 seasons. For this reason the civil year has been introduced. 
 The Roman emperor, Julius Caesar, ordered that three suc- 
 cessive years should have 365 days each and the fourth^ 
 year should have 366 days. 
 
 The fourth year, containing 366 days, is called a leap 
 year, because it leaps over, or gains, the difference between 
 the civil and siderial time of the preceding three years. For 
 convenience the leap year was designated as any year whose 
 number is exactly divisible by 4. This is called the Julian 
 calendar. 
 
 But as a siderial year is 365 days, 6 hours, 9 minutes, 
 9.5 seconds of mean time, the addition of one day of twen- 
 ty-four hours would not exactly balance the two calendars ; 
 therefore Pope Gregory XIIL, in 1582, ordered that every 
 year whose number is a multiple of 100 shall be a year of 
 365 days, unless the number of the year is divisible by 400, 
 when it shall be a leap year of 366 days. 
 
 The calendar constructed in this way is called the Gre- 
 gorian calendar, and is the one in common use. Its error 
 is very small and will amount to only i day, 5 hours, 30 
 minutes in 4,000 years. 
 
 The revolution of the moon around the earth in relation 
 to the stars, takes place in 2"/ days, 7 hours and 43 minutes ; 
 this is called a siderial month. But during this period the 
 earth has advanced along the plane of its path about the sun 
 and the moon must make up this distance in order to re- 
 
35° 
 
 THE MODERN CLOCK. 
 
 turn to the same point in relation to the sun. This period 
 is called a synodic month. Its average length is 29 days, 
 12 hours, 44 minutes, 2.9 seconds. 
 
 Having now understood these differences we shall be 
 able to intelligently examine the various calendar mechan- 
 isms on the market and understand the reasons for their 
 apparent departures from regular mechanical progression, 
 as the equation of time gives us the difference between real 
 and mean apparent, or solar time; we regulate our clocks 
 by means of siderial time; the irregular procession of 30 
 and 31 days makes the civil calendar agree with the seasons, 
 or the tropical year, and the remainder of the discrepancy 
 between civil and siderial time is made up in February at 
 the period when it is of the least consequence. 
 
 Simple Calendar Work. — Fig. iii shows the Ameri- 
 can method of making a simple calendar, the example 
 shown being drawn from a movement of the Waterbury 
 Clock Company as a typical example. A'o attempt is made 
 here to show the day of the week or the month. The days 
 of the month are shown by a series of numbers from i to 31, 
 arranged concentrically with- the tim.e dial and the current 
 day is indicated by a hand of different color, carried on a 
 pipe outside the pipe of the hour hand on the center arbor. 
 
 In order to accomplish this the motion work for the 
 hands is mounted inside the frames, the hour pipe and 
 center arbor being suitably lengthened. In the Figure A 
 is the cannon pinion ; B, the minute wheel ; C, the 
 minute pinion ; D, the hour wheel at the rear end of 
 the hour pipe; this pipe projects through the frame and 
 forms a bearing in the frame for the center arbor. Fric- 
 tion-tight on the hour pipe, in front of the front plate, is 
 the pinion E, which drives a wheel F of twice as many 
 teeth. This wheel F is mounted loosely on a stud and has 
 a pin which meshes with the teeth of a ratchet wheel G. G 
 is carried at the bottom end of a pipe which fits loosely on 
 
THE MODIiltX CLOCK. 
 
 351 
 
 Fig. 111. Simple calendar on time train. 
 
352 THE MODERN CLOCK. 
 
 the hour pipe and carries the calendar hand H under the 
 hour hand and close to the dial. The pinion on the hour 
 pipe revolves once in twelve hours. The wheel E has twice 
 
 yig. 112. Calendar work for grandfather clocks. 
 
 as many teeth and will therefore revolve once in twenty- 
 four hours. It moves the ratchet G one tooth at each revo- 
 lution ; therefore the hand H moves one space every twenty- 
 four hours. There arc 31 teeth, so that the hand must be 
 set forward every time it reaches the 28th and 29th of Feb- 
 
THE MODERN CLOCK. 353 
 
 ruary and the 30th of April, June, September and Novem- 
 ber. This is the simplest and cheapest of all the calendars, 
 occupies the least space and is frequently attached to nickel 
 alarm clocks for that reason. 
 
 A simple calendar work often met with in old clocks of 
 European origin is shown in Fig. 112. Gearing with the 
 hour wheel is a wheel, A, having twice its number of 
 teeth, and turning therefore once in twenty-four hours. A 
 three-armed lever is planted just above this wheel; the 
 lower arm is slotted and the wheel carries a pin which 
 works in this slot, so that the lever vibrates to and fro once 
 every twenty-four hours. The three upper wheels, B, C 
 and D in the drawing, represent three star wheels. B has 
 seven teeth, corresponding to the days of the week; C has 
 31 teeth, for the days of the month; and D has 12 teeth, 
 for the months of the year. Each carries a hand in the 
 center of a dial on the other side of the plate. Every time 
 the upper arms of the lever vibrate they move forward the 
 day of the week, B, and the day of the month, C, wheels 
 each one tooth. The extremities of the two upper levers 
 are jointed so as to yield on the return vibration, and are 
 brought into position again by a weak spring. There is a 
 pin in the wheel, C, which, by pressing on a lever once 
 every revolution, actuates the month of the year wheel, D. 
 This last lever is also jointed, and is pressed on by a spring 
 so as to return to its original position. Each of the star 
 wheels has a click kept in contact by means of a spring. 
 For months with less than 31 days, the day of the month 
 hand has to be shifted forward. 
 
 Perpetual Calendar Work. — Figs. 113, 114, 115, show 
 a perpetual calendar which gives the day of the week, day 
 of the month and the month, making all changes automati- 
 cally at midnight, and showing the 31 days on a dial be- 
 neath the time dial, by means of a hand, and the days of 
 the week and the month by means of cylinders operating 
 
■354 
 
 THE MODERN CLOCK. 
 
 -O 
 
 A^>K 
 
 IP 1 
 
 
 
 'tS^^^^^E-T^^ ^ 
 
 - 
 
 IIP'J ■ 
 
 
 r^ 
 
 -jK 
 
 ii:0 
 
 Fig. 113. Perpetual Calendar Movement. 
 
THE MODERN CLOCK. 353 
 
 behind slots in the dial on each side of the center. This 
 is also a Waterbury movement. ' 
 
 A pinion on the hour pipe engages a wheel, A, having 
 twice the number of teeth and mounted on an arbor which 
 projects through both plates. The rear end of this arbor 
 carries a cam, B, on which rides the end of a lever, C, which 
 is pivoted to the rear frame. The lever is attached to a 
 wire, D, which operates a sliding piece, E, which is weight- 
 ed at its lower end. The cam, \yhich, of course, revolves 
 once in twenty- four hours, drops its lever at midnight and 
 the weight on E pulls it down. E bears a spring pawl, F, 
 which on its way down, raises the spring actuated retaining 
 click, H, and then moves the 31 -toothed wheel G one notch. 
 This wheel is mounted on the arbor which carries the hand 
 and, of course, advances the hand. 
 
 Lying on top of the wheel, G, is a cam, I, pivoted to G 
 near its circumference and having an arm reaching toward 
 the months cylinder and another reaching towards the right 
 leg of the pawl, H, while it is cut away in the center, so as 
 to clear the center arbor carrying the hand. Trace this cam, 
 I, carefully in Figs. 113 and 114, as its action is vital. The 
 lower arm of this cam is shown more clearly in Fig. 114. 
 It projects above the wheel and engages the long teeth, J, 
 and the cam, K, mounted on the year cylinder arbor; 
 where the lower arm of I strikes one of these teeth it shoves 
 the upper arm outward, so that it strikes the retaining end 
 of the pawl, H, and holds it up, and the descending pawl, 
 F, may then push the wheel, G, forward for more than one 
 tooth. The upper end of I is broad enough to cover three 
 teeth of the wheel, G, when pushed outward, and the slot 
 in E is long enough so that F may descend far enough to 
 push G forward three teeth at once, unless it is stopped by 
 H falling into a tooth, so that the position of I, when it is 
 holding up H and the extra drop thus given to E serve to 
 operate the jumps of 30 to i, 28 to i and 29 to i of the hand' 
 on the dial. The teeth, J, Fig. 1 14, operate for two notches, 
 
35^ 
 
 THE MODERN CLOCK, 
 
 Fig. 114. The months change gear. 
 
THE MODERN CLOCK. ^fi^^ 
 
 thus making the. changes from 30 to i. The wide tooth, M, 
 and cam, K, acting together, make the change for February 
 from 28 to 31. The 29th day is added by the movement of 
 the cam, K, narrowing the acting surface once in four years, 
 as follows: 
 
 Looking at Fig. 114 we see an ordinary stop works fin- 
 ger, mounted on the months arbor and engaging a four- 
 armed maltese cross on the wheel. Behind the wheel is a 
 circular cam (shown dotted in) with one-fourth of its cir- 
 cumference cut away; the pivot holds the cam and cross 
 rigidly together while permitting them to revolve loosely in 
 the wheel. The cam, K, lies close to the w^heel and is 
 pressed against the cam on the cross by a spring, so that 
 ordinarily the full width of M and K act as one piece on 
 the end of the cam, I, which thus is pressed against the 
 retaining pawl, H, during the passage of three teeth, mak- 
 ing the jump from 28 to i each of these three years. 
 
 The fourth revolution of the maltese cross brings the cut 
 portion of its cam to operate on K and allows K to move 
 tehind M, thus narrowing the acting surface so that I only 
 covers two teeth (30 and 31) for every fourth revolution 
 of the month's cylinder, thus making the leap year every 
 fourth year. 
 
 The months cylinder is kept in position by the two-armed 
 pawl, N, engaging the teeth, L, which stand at 90 degrees 
 from the wheel, as shown in Fig. 113. Attached to the 
 bearing for the week cylinder (not shown) is one revolu- 
 tion of a screw track, or worm, surrounding the arbor for 
 the hand. Attached to the arbor is a finger, O, held taut 
 by a spring and engaging the track, P. The revolution of 
 the arbor raises O on P until it slips off, when O, drawn 
 downward by its spring, raises the pawl, N, drops on one 
 of the teeth, L, and revolves the cylinder one notch. 
 
 Q is a shifter for raising the pawl, H, and allowing the 
 hand to be set. 
 
358 
 
 THE MODERN CLOCK. 
 
 Fig. 115. The weeks chaage gear. 
 
THE MODERN CLOCK. 3.^^ 
 
 Fig. 115 shows the inner end of the cyHnder for the days 
 of the week. There are two sets of these and fourteen 
 teeth on the sprocket, R, so as to get the two cyHnders ap- 
 proximately the same size (there being 14 days and 12 
 months on the respective cyHnders). S is a pawl whose 
 upper end is forked so as to embrace a tooth and hold the 
 cylinder in position. T is a hook, carried on the sliding 
 piece, E, which swings outward in its upward passage as E 
 is raised and on its downward course raises the pawl, S, 
 and revolves the sprocket, R, one tooth, thus changing the 
 day of the week at the same time the hand is advanced. 
 
 To set the calendar, raise the pawl, N, and revolve the 
 year cylinder until M and K are at their narrowest width ; 
 that is, a leap year. Then give the year cylinder as many 
 additional turns as there are years since the last leap year, 
 stopping on the current month of the current year. For 
 instance, if it is two years and four months since the 29th 
 of February last occurred, give the cylinder 2 and 4/12 
 turns which should bring you to the current month, raise 
 the shifter, Q, and set the hand to the current day. Then 
 raise the pawl, S, and set the week cylinder to the current 
 day. Place the hour hand on the movement so that the cam 
 will drop E at midnight. 
 
 Fig. 116 shows the dial of Brocot's calendar work, which, 
 with or without the equation of time and the lunations, is 
 to be met with in many grandfather, hall and astronomical 
 clocks. We will assume that all of these features are pres- 
 ent, in order to completely cover the subject. It consists of 
 two circular plates of which the front plate is the dial and 
 the rear plate carries the movement, arranged on both sides 
 of it. All centers are therefore concentric and we have 
 marked them all with the same letters for better identifica- 
 tion in the various views as the inner plate is turned about 
 to show the reverse side, thus reversing the position of right 
 to left in one view of the inner plate. 
 
360 
 
 THE MODERN CLOCK. 
 
 Fig. 117 shows the wheel for the phases of the moon, 
 which is mounted on the outside of the inner plate imme- 
 diately behind the opening in the dial. The dark circles 
 h'ave the same color as the sky of the dial and the rest is 
 gilt, white or cream color to show the moon as in Fig. 116. 
 
 \ \ i 
 
 ^ V \ ^ ' • I ' ' ' / / -\ 
 
 y v<>^e*t^ ^^"'^-^^ 
 
 Fig. 116. Dial of Brocot's Calendar. 
 
 The position of this plate is also shown in Fig. 120. By 
 the dotted circles, about the center D. 
 
 The inner side containing the mechanism for indicating 
 the days of the week and the days of the month is shown in 
 Fig. 118. The calendar is actuated by means of a pin, C, 
 fixed to a wheel of the movement which turns once in 
 twenty-four hours in the manner previously described with 
 
THE MODEUN CLOCK. 361 
 
 Fig. 113. Two clicks, G and H, arc pivoted to the lever, 
 M. G, by means of its weighted end, see Fig. 119, is kept 
 in contact with a ratchet wdieel of 31 teeth, and H with a 
 ratchet wheel of 7 teeth. As a part of these clicks and 
 wheels is concealed in Fig. 118, they are shown separately 
 in Fig. 119. 
 
 When the lever, AI, is moved to the left as far as it will 
 go by the pin, e, the clicks, G and H, slip under the teeth ; 
 their beaks pass on to the following tooth ; when e has 
 moved out of contact the lever, M, falls quickly by its own 
 weight, and makes each click leap a tooth of the respective 
 wheels, B of 7 and A of 31 teeth. The arbors of these 
 wheels pass through the dial (Fig. 116), and have each an 
 index which, at every leap of its own wheel, indicates on its 
 special dial the day of the week and the day of the month. 
 A roll, or click, kept in position by a sufficient spring, keeps 
 each wheel in its place during the interval of time which 
 separates two consecutive leaps. 
 
 This motion clearly provides for the indication of the day 
 of the week, and would be also sufficient for the days of 
 the month if the index were shifted by hand at the end of 
 the short months. 
 
 To secure the proper registration of the months of 30 
 days, for February of 28 during three years, and of 29 in 
 leap year, we have the following provision : The arbor, A, 
 of the day of the month wheel goes through the circular 
 plate, and on the other side is fixed (see Fig. 120) a pinion 
 of 10 leaves. This pinion, by means of an intermediate 
 wheel, I, works another w^heel (centered at C) of 120 
 teeth, and consequently turning once in a year. The arbor 
 of this last wheel bears an index indicating the name of the 
 month, G, Fig. 116. The arbor, C, goes through the plate, 
 and at the other end, C, Fig. 118, is fixed a little wheel 
 gearing with a wheel having four times as many teeth, and 
 which is centered on a stud in the plate at F. This wheel 
 is partly concealed in Fig. 118 by a disc V, which is fixed 
 
362 THE MODERN CLOCK. 
 
 to it, and with the wheel makes one turn in four years. On 
 this disc, V, are made 20 notches, of which the 16 shallow- 
 est correspond to the months of 30 days ; a deeper notch 
 corresponds to the month of February of leap year, and the 
 last three deepest to the month of February common years 
 in each quarternary period. The uncut portions of the disc 
 correspond to the months of 31 days in the same period. 
 The wheel. A, of 31 teeth, has a pin (i) placed before the 
 tooth which corresponds to the 28th of the month. On the 
 lever, M, is pivoted freely a bell-crank lever (N), having at 
 
 Fig. 117. Dial of Moon's Phases. 
 
 the extremity of the lower arm a pin (o) which leans its 
 own weight upon the edge of the disc, V, or upon the bot- 
 tom of one of the notches, according to the position of the 
 month, and the upper arm of N is therefore higher or lower 
 according to the position of the pin, o, upon the disc. 
 
 It will be easy to see that when the pin, o, rests on the 
 contour of the disc the upper arm, N, of the bell-crank 
 lever is as high as possible, and out of contact with the pin 
 as it is dotted in the figure, and then the 31 teeth of the 
 month wheel will each leap successively one division by the 
 action of the click, G, as the lever, M, falls backward till 
 the 31st day. But when the pin, o, is in one of the shal- 
 low notches of the plate, V, corresponding to the months of 
 30 days, the upper arm, N, of the bell-crank lever will take 
 
THE MODERN CLOCK. 
 
 363 
 
 Fig. 118. Brocot's Calendar; Rear View of Calendar Plate showing 
 Four Year Wheel and Change Mechanism, 
 
364 
 
 THE MODERN CLOCK. 
 
 a lower position, and the inclination that it will have by the 
 forward movement of the lever, M, will on the 3Qth bring 
 the pin, i, in contact with the bottom of the notch, just as 
 the lever, M, has accomplished two-thirds of its forward 
 movement, so the last third will be employed to make the 
 wheel 31 advance one tooth, and the hand of the dial by 
 consequence marks the 31st, the quick, return of the lever, 
 M, as it falls putting this hand to the ist by the action of 
 the click, G. If we suppose the pin, o, is placed in the shal- 
 
 Fig. 119. Change Mechanism behind the Four Year Wheel in Fig. 118 
 
 lowest of the four deep notches, that one for February of 
 leap year, the upper end of the arm, N, will take a position 
 lower still, and on the 29th the pin, i, will be met by the 
 bottom of the notch, just as the lever has made one-third of 
 its forward course, so the other two-thirds of the forward 
 movement will serve to make two teeth of the wheel of 31 
 jump. Then the hand of the dial, A, Figs. 116 and 118, 
 will indicate 31, and the ordinary quick return of the lever, 
 M, with its detent, G, will put it to the 1st. Lastly, if, as 
 it is represented in the figure, the pin, o, is in one of the 
 three deepest notches, corresponding to the months of Feb- 
 ruary in ordinary years, the pin will be in the bottom of 
 
THE MODERN CLOCK. 365 
 
 the notch on the 28th just at the moment the lever begins 
 its movement, and three teeth will pass before the return 
 of the lever makes the hand leap from the 31st to the ist. 
 
 The pin, 0, easily gets out of the shallow notches, which, 
 as will be seen, are sloped away to facilitate its doing so. 
 To help it out of the deeper notches there is a weighted 
 finger (j) on the arbor of the annual wheel. This finger, 
 having an angular movement much larger than the one of 
 the disc, V, puts the pin, o, out of the notch before the notch 
 has sensibly changed its position. 
 
 Phases of the Moon. — The phases of the moon are ob- 
 tained by a pinion of 10, Fig. 120, on the arbor, B, which 
 gears with the wheel of 84 teeth, fixed on another of 75, 
 Avhich last gears with a wheel of 113, making one revolu- 
 tion in three lunations. By this means there is an error 
 only of .00008 day per lunation. On the wheel of 113 is 
 fixed a plate on which are three discs colored blue, having 
 between them a distance equal to their diameter, as shown, 
 in Fig. 117, these discs slipping under a circular aperture 
 made in the dial, produce the successive appearance of the 
 phases of the moon. 
 
 Equation of Time. — On the arbor of the annual wheel, 
 C, Figs. 116, 118, 120, is fixed a brass cam, Y, on the edge 
 of which leans the pin, s, fixed to a circular rack, R. This 
 rack gears with the central wheel, K, which carries the 
 hand for the equation. That hand faces XII the 15th of 
 April, 14th of June, ist of September and the 25th of De- 
 cember. At those dates the pin, s, is in the position of the 
 four dots marked on the cam, Y. The shape of the cam, 
 Y, must be such as will lead the hand to indicate the dif- 
 ference between solar and mean time, as given in the table 
 of the Nautical almanac. 
 
 To set the calendar first see that the return of the lever, 
 M, be made at the moment of midnight. To adjust the 
 hand of the days of the week, B, look at an almanac and 
 
366 
 
 THE MODERN CLOCK. 
 
 see what day before the actual date there was a full or new 
 moon. If it was new moon on Thursday, it would be nec- 
 essary, by means of a small button fixed at the back, on the 
 arbor of the hand of the wheel, B, of the week, to make as 
 many returns as requisite to obtain a new moon, this hand 
 
 S'/T 
 
 s-m^- 
 
 Fig. 120. Brocot's Calender: "Wheels and Pinions under the Dial with 
 their Number of Teeth. 
 
 pointing. to a Thursday; afterward bring back the hand to 
 the actual date, passing the number of divisions correspond- 
 ing to the days elapsed since the new moon. To adjust the 
 hand of the day of the month, A, see if the pin, o, is in the 
 proper notch. If for the leap year, it is in the month of 
 February in the shallowest of the four deep notches (o) ; 
 if for the same month of the first year after leap year, then 
 the pin should be, of course, in the notch, i, and so on. 
 
CHAPTER XX. 
 
 HAMMERS, GONGS AND BELLS. 
 
 Just as the tone of a piano depends very largely upon the 
 condition of the felts on the hammers which strike the 
 wires, so does the tone of a clock gong or bell depend on 
 its hammer action. The deep, soft, resonant tone in either 
 instance depends on the vibration being produced by some- 
 thing softer than metal. Ordinarily this condition is reached 
 by facing the hammer with leather. The second essential 
 is that the hammer shall immediately rebound, clear of the 
 bell, so as not to interfere with the vibrations it has set up 
 in the bell, wire or tube. As the leather gets harder the 
 tone becomes harsher and ''tinny," sometimes changing to 
 another much higher tone and entirely destroying the 
 harmony. The remedy is either to oil the leather on the 
 hammers, or if they are much worn to substitute new and 
 thicker leathers until the tone is sufficiently mellowed, so 
 that a vigorous blow will still produce a mellow tone of 
 sufficient carrying power. A piece of round leather belting 
 will be found very convenient for this purpose. 
 
 The superiority of a chiming clock lies in its hammer 
 action. If this mechanism is not perfect, only inferior re- 
 sults can be obtained. The perfect hammer is the one that 
 acts with the smallest strain and is operated with the least 
 power. Heavy weights create a tremendous strain on the 
 mechanism and bring disastrous results when one of the 
 suspending cords break. The method of lifting the ham- 
 mer is one of importance, and the action of the hammer 
 spring is but seldom right on old clocks brought in for re- 
 pairs, especially if it be a spring bent oyer to a right angle 
 
 367 
 
368 THE MODERN CI.OCK. 
 
 at its point. If there are two springs, one to force the ham- 
 mer down after the clock has raised it up, and another 
 shorter one, fastened on to the pillar, tO' act as a counter- 
 spring and prevent the hammer from jarring on the bell, 
 there will seldom be any difficulty in repairing it; and the 
 only operation necessary to be done is to file worn parts, 
 polish the acting parts, set the springs a little stronger, and 
 the thing is done. But if there is only one spring some 
 further attention will be necessary, because the action of the 
 one spring answers the purpose of the two previously men- 
 tioned, and to arrange it so that the hammer will be lifted 
 with the greatest ease and then strike on the bell with the 
 greatest force, and without jarring, requires some experi- 
 ence. That part of the hammer-stem which the spring acts 
 on should never be filed or bent beyond the center of the 
 arbor, as is sometimes done, because in such a case the ham- 
 mer-spring has a sliding motion when it is in action, and 
 some of the force of the spring is thereby lost. The point 
 of the spring should also be made to work as near to the 
 center of the arbor as it is possible to get it, and the flat 
 end of the spring should be at a right angle with the edge 
 of the frame, and that part of the hammer-stem that strikes 
 against the flat end of the spring should be formed with a 
 curve that will stop the hammer in a particular position and 
 prevent it jarring on the bell. This curve can only be deter- 
 mined by experience ; but a curve equal to a circle six inches 
 in diameter will be nearly right. 
 
 The action of the pin wheel on the hammer-tail is also 
 of importance. The acting face of the hammer-tail should 
 be in a line with the center of the pin-wheel, or a very little 
 above it, but never below it, for then it becomes more dif- 
 ficult for the clock to lift the hammer, and the hammer- 
 tail should be of such a length as to drop from the pins of 
 the pin-wheel, and when it stops be about the distance of 
 two teeth of the wheel from the next pin. This allows the 
 wheel- work to gain a little force before lifting the hammer, 
 
THE MODERN CLOCK. 369 
 
 which is sometimes desirable when the clock is a little dirty 
 or nearly run down. We might also mention that in set- 
 ting the hammer-spring to work with greater force it" is 
 always well to try and stop the fly with your finger when 
 the clock is striking, and if this can be done it indicates 
 that the hammer spring is stronger than the striking power 
 of the clock can bear, and it ought to be weakened, because 
 the striking part will be sure to stop whenever the clock 
 gets the least dirty. 
 
 Gong wires are also the cause of faulty tones. In the 
 factories these are made by coiling wires of suitable lengths 
 and sections on arbors in a lathe. They are then heated to 
 a dull red and hardened by dipping in water or oil. After 
 cooling they are trued in the round and the flat like a watch 
 hairspring and then drawn to a blue temper. The tone 
 comes with the tempering, and if they are afterwards bent 
 beyond the point where they will spring back to shape the 
 tone is interfered with. Many repairers, not being aware 
 of this fact, have ruined the tone of a gong wire while try- 
 ing to true it up by bending with pliers. When the owner 
 is particular about the tone of the clock, a new gong should 
 always be put in if the old one is badly bent. 
 
 The wires are soldered to their centers and if they are 
 at all loose they should be refastened in the same manner 
 if it can be done without drawing the temper of the wire. 
 When this cannot be done a plug of solder may be driven 
 in between the wire and the side of the hole so as to stop 
 all vibration or the solder already in place may be driven 
 down so as to make all tight, as any vibration at this point 
 will interfere with the tone. 
 
 Tuning the Bells. — Bells only vefy slightly out of 
 tone offend the musical ear, and they may easily be correct- 
 ed to the extent of half a tone. To sharpen the tone make 
 the bell shorter by turning away the edge of it if it be a 
 shell, or by cutting off if it be a rod or tube ; to flatten the 
 
370 
 
 THE MODERN CLOCK. 
 
 -T1C10D 
 
 ^. 
 
 %i 
 
 it 
 
 3; 
 
 ^ 
 
 2c 
 
 i=iE 
 
 5E 
 
 ■rJ 
 
 yi 
 
 >1 
 
 Fig. 121. The pins in the chiming barrels. 
 
THE MODERN CLOCK. 37t 
 
 tone, thin the back basin-shaped part of the bell by turn- 
 ing some off the outside. Bells which are cracked give a 
 poor sound because the edges of the crack interfere with 
 each other when vibrating. They may be repaired by saw- 
 ing through the crack to the end of it, so that the edges will 
 not touch each other when vibrating. If there is danger of 
 the crack extending further into the bell, first drill a round 
 hole in the soHd metal just beyond the end of the crack, 
 and then saw through into the hole ; this will generally pre- 
 vent any further trouble. 
 
 Marking the Chime Barrel. — The chime barrel in 
 small clocks is of brass and should be as large in diameter 
 as "can be conveniently got in. To mark off the positions of 
 the pins for the Cambridge chimes, first put the barrel in 
 the lathe and trace circles round the barrel at distances 
 apart corresponding to the positions of the hammer tails. 
 There are five chimes of four bells each for every rotation 
 of the barrel, and a rest equal to two or three notes be- 
 tween each chime. Assuming the rest to be equal to three 
 notes, divide the circumference of the barrel into thirty- 
 five equal parts by means of an index plate, and draw lines 
 at these points across the barrel with the point of the tool 
 bv moving it with the slide rest screw. Call the hammer 
 for the highest note D, and that for the lowest note F. 
 Then the first pin is to be inserted where one of the lines 
 across the barrel crosses the first circle; the second pin 
 where the next line crosses the second circle; the third pin 
 where the third line crosses the third circle and the fourth 
 pin where the fourth line crosses the four circle, because 
 the notes of the first chime are in the order, D, C, Bb, F. 
 Then miss three lines for the rest. The first note of the 
 second chime is Bb and the pins for it will consequently be 
 inserted where the first line after the rest crosses the third 
 circle, and so on. Where two or more notes on the same 
 bell come so close as to make it difficult to strike them prop- 
 
372 
 
 THE MODERN CLOCK. 
 
 erly, it is usual to put in another hammer, as it shown in 
 Fig. 121, where there are two Fs. In fine clocks the pins 
 are of varying lengths so as to strike the hammers on the 
 bells with varying force and thus give more expression to 
 the music. 
 
 The following gives the Cambridge Chimes, which are 
 used in the Westminster Great Clock. They are founded 
 on a phrase in the opening symphony of Handel's air, 'T 
 
 1st 
 Quarter 
 
 2nd . 
 Quarter. 
 
 3rd 
 Quarter. 
 
 ^ 
 
 ^ 
 
 ^s 
 
 t 
 
 i 
 
 ^ 
 
 ^ 
 
 3te 
 
 22: 
 
 ■ f^^^M^gJfFF ? ^! 
 
 Hour. 
 
 i 
 
 &i 
 
 m^- 
 
 i3t 
 
 ^^^ 
 
 $ 
 
 t 
 
 ^^ 
 
 22: 
 
 H^M 
 
 Fig. 122. Westminster chimes. 
 
 know that my Redeemer liveth," and were arranged by Dr. 
 Crotch for the clock of Great St. Mary's, Cambridge, in 
 1793- 
 
 In Europe these chiming clocks are sometimes very elab- 
 orate, as the following description of a set of bells in Bel- 
 gium will show: 
 
 "So far as the experience of the writer goes the Belgian 
 carillons are invariably constructed on one prevailing plan, 
 with the exception that the metal used for the cylinder is 
 generally brass; here, however, it is of steel, and consists 
 of a large barrel measuring 4 feet 2 inches in width and 3 
 
THE MODERN CLOCK. 373 
 
 feet 6 inches in diameter, its surface being pierced with 
 horizontal lines of small square holes about ^ inch square. 
 There are lines of 60 of these in the width of the barrel, 
 while there are 120 lines of them round the circumference, 
 making a total of 7,200 holes. The drilling of these, of 
 course, takes place when the cylinder is made, and, so far 
 as this part is concerned, the barrel is complete before it is 
 brought to the tower. 
 
 "Into these square holes are fixed the 'pins,' adjusted on 
 the inside of the cylinder by nuts. 
 
 "The pins are of steel of finely graduated sizes, corres- 
 ponding with the value of the notes of music. Some idea 
 of the precision obtainable may be gathered by the fact, as 
 the carillonneur told the writer, that there were no less 
 than 24 grades of pins, so as to insure the greatest accuracy 
 of striking the bells. 
 
 "Over the cylinder are 60 steel levers with steel nibs; 
 these are lifted by the 'pins' and, connected by wires with 
 the hammers, strike the bells. 
 
 "The 35 bells are furnished with J2 hammers, which are 
 fixed as ordinary clock-hammers outside of the bells; three 
 of the bells (in the ring of eight) have a single hammer 
 only, the limited space in the 'cage' making it impossible 
 to put more, while others are supplied with two or three 
 apiece for use in rapidly repeating notes of the music. On 
 a visit some years ago to the carillon at Malines, the writer 
 noticed that some of the bells there had no less than five 
 hammers apiece. 
 
 "Obviously, though there are 'J2 hammers in connection 
 with the carillon, only 60, corresponding with the number 
 of levers, can be used at one time; these are selected ac- 
 cording to the requirement of the tune; in case of new 
 tunes, the wires can easily be adjusted so as to bring other 
 hammers and bells into use. 
 
 "The feature of the Belgian carillons is that instead of 
 the single notes of the air being struck as with the old 
 
374 '^^^E MODERN CLOCK. 
 
 familiar 'chimes/ harmonized tunes of great intricacy are 
 rendered with chords of three, four or even five bells strik- 
 ing at one time. 
 
 "The cylinder here is capable of 120 'measures' of music, 
 but^as „ a matter of fact it is subdivided so that half a revo- 
 lution plays every hour. 
 
 "A march is, as a rule, played at the odd hours, and the 
 national air at the even, but the bells are silent after 9 p. m. 
 and start again at 8 a. m. 
 
 "The motive power is supplied by a weight of 8 cwt., 
 and is controlled by a powerful fly of four fans artistically 
 formed to represent swans. It may be mentioned that the 
 keyboard for hand-playing consists of thirty-five keys of 
 wood and eleven pedals; these, as indeed the whole appa- 
 rartus of this part, are entirely separate from the automatic 
 carillon ; in this instance the keys connect with the clappers 
 of the bells and have no association with the hammers. 
 The pedals are connected with the eleven largest bells and 
 are supplementary to the hour key." 
 
 Tubular Chimes are tubes of bell metal, cut to the 
 proper lengths to secure the desired tones and generally, 
 but not always, nickel plated. As they take up much room 
 in the clock, they are generally suspended from hooks at 
 the top of the back board of the case, being attached to the 
 hooks by loops of silk or gut cords, passed through holes 
 drilled in the wall of the tubes near the top ends. The hour 
 tube, being long and large, generally extends nearly to 
 the bottom of a six-foot case, while the others range up- 
 wards, shortening according to the increase of pitch of the 
 notes which they represent. 
 
 This makes it necessary to place the movement on a seat 
 board and hang the pendulum from the front plate of the 
 movement, so that such clocks have, as a rule, comparative- 
 ly light pendulums. On account of the position and the 
 great spread of the tubes, the chiming cylinder and ham- 
 mers are placed on top of the movement, parallel with the 
 
TIIF MODERN CLOCK. 375 
 
 plates, and operated from the striking train by means of 
 bevel gears or a contrate wheel. The hammers are placed 
 vertically on spring hammer stalks and connected with the 
 chiming cylinder levers by silken cords. This gives great 
 freedom of hammer action and results in very perfect tones. 
 The hammers must of course be each opposite its own 
 tube and thus they are rather far apart, which necessitates 
 a long cylinder. This gives room for several sets of 
 chimes on the same cylinder if desired, as a very slip^ht 
 horizontal movement of the cylinder would move the pins 
 out of action with the levers and bring another set into 
 action or cause the chimes to remain silent. 
 
 Practically all of the manufacturers of "hall" or chim- 
 ing clocks import the movements and supply American 
 cases, hammers and bells. The reason is that there is so 
 little sale for them (from a factory standpoint) that one 
 factory could supply the world with movements for this 
 class of clocks without working overtime, and therefore it 
 would be useless to make up the tools for them when they 
 can be bought without incurring that expense. 
 
CHAPTER XXL 
 
 ELECTRIC CLOCKS AND BATTERIES. 
 
 Electric clocks may be divided into three kinds, or prin- 
 cipal divisions. Of the first class are those in which the 
 pendulum is driven directly from the armature by electric 
 impulse, or by means of a weight dropping on an arm pro- 
 jecting from the pendulum. In this case the entire train of 
 the clock consists of a ratchet wheel and the dial work. 
 
 The second class comprises the regular train from the 
 center to the arbor. This class has a spring on the center 
 arbor, wound more or less frequently by electricity. In 
 this case the aim is to keep the spring constantly wound, so 
 that the tension is almost as evenly divided as with the 
 ordinary weight clock, such as is used in jewelers' regu- 
 lators. 
 
 The third system uses a weight on the end of a lever 
 connected with a ratchet wheel on the center arbor and . 
 does away with springs. One type of each of these clocks 
 will be described so that jewelers may comprehend the prin- 
 ciples on which the three types are built 
 
 In the Gillette Electro-Automatic, which belongs to the 
 class first mentioned, the ordinary clock principle is re- 
 versed. Instead of the works driving the pendulum, the 
 pendulum drives the train, through the medium of a pawl 
 and ratchet mechanism on the center arbor. The pendu- 
 lum is kept swinging by means of an impulse given every 
 tenth beat by an electro-magnet. This impulse is caused 
 by the weight of the armature as it falls away from the 
 magnet ends, the current being used solely to pull back and 
 re-set the armature for the next impulse. Any variation in 
 the current, therefore, does not affect the regulation of the 
 
 376 
 
THE MODERN CLOCK 
 
 377 
 
 Fig. 123. Gillette Clock (Pendulum Driven) 
 
378 THE MODERN CLOCK. 
 
 clock, as the power is obtained from gravity only, by 
 means of the falling weight. Referring to the drawings. 
 Figs. 123 and 124, it is seen that each time the pendulum 
 swings the train is pushed one tooth forward. A cam is 
 carried by the ratchet (center) arbor in which a slot is pro- 
 vided at a position equivalent to every fifth tooth of the 
 ratchet. Into this slot drops the end of a, lever, releasing at 
 its other end the armature prop. Thus at the next beat of 
 the pendulum the armature is released and in its downward 
 swing impulses the pendulum, giving it sufficient mo- 
 mentum to carry it over the succeeding five swings. 
 
 The action of the life-giving armature is entirely discon- 
 nected and independent of the clock mechanism. It acts 
 on its own accord when released every tenth beat and auto- 
 matically gives its impulse and re-sets itself. It is pro- 
 vided with a double-acting contact spring (see Fig. 125) 
 which "flips" a contact leaf from one adjustable contact 
 screw to the other as the action of the armature causes the 
 spring to pass over its dead center. Thus, when the arma- 
 ture reaches the lowest point in its drop (Figs. 126 and 
 127) the leaf snaps against the right contact screw, the cir- 
 cuit is completed, the magnet energized and the armature 
 drawn up. As the armature rises above a certain point, the 
 dead center of the flipper spring is again crossed and the 
 leaf snaps back against the post at the left. In the mean- 
 time, however, the armature prop has slipped under the end 
 of the armature and retains it until the time comes for the 
 next impulse. 
 
 In adjusting the mechanism of this type of clock the in- 
 creasing pendulum swing should catch and push the ratchet 
 before the buffer strikes and lifts the armature from the 
 prop. The adjustment of the "flipper" contact screws 
 (with 1-32 inch play) should be such that as the armature 
 falls the contact leaf will be thrown and the armature 
 drawn up at a p9int just beyond the half-way position in 
 the swing of the pendulum. The power of the impulse can 
 
THE MODERN CLOCK. 
 
 379 
 
 Fig. 124. Side View. 
 
3S0 THE MODERN CLOCK. 
 
 be regulated by turning the adjusting post with pHers, thus 
 varying the tension of the armature spring, the pull of 
 which reinforces the weight of the armature. • Care should 
 be taken, however, that the tension is not beyond the "quick 
 action" power of the electro-magnet. It is much better to 
 ease up the movement in other ways before putting too 
 great a load on the life of the battery. 
 
 The electrical contacts on the leaf and screw are platinum 
 tipped to prevent burning by the electric sparking at the 
 ''make" and ''break." This sparking is also much reduced 
 by means of a resistance coil placed in series connection 
 with the magnet coil, Fig. 127, to reduce the amount of 
 current used. If this coil is removed or disconnected the 
 constant sparking and heat would soon burn out the con- 
 tact tips. 
 
 Care should be taken to see that the batteries are dated 
 and the battery connections are clean at the time of sliding 
 in a new battery. The brush which makes connection with 
 the center or carbon post of the battery is insulated with 
 mica from the framework of the case. The other connec- 
 tion is made from the contact of the uncovered zinc case of 
 the battery with the metal clock case surrounding it. The 
 contact points should be bright and smooth to insure good 
 contacts. 
 
 These clocks need but little cleaning of the works as no 
 oil whatever is used, except at one place, viz., the armature 
 pivot. Oil should never be used on the train bearings, or 
 other parts. This clock ran successfully on the elevated 
 railway platforms of the loop in Chicago where no other 
 pendulum clock could be operated on account of the con- 
 stant shaking. 
 
 In considering the electrical systems of these clocks, let 
 us commence with the batteries. While undoubtedly great 
 improvements have been made in the present form of dry 
 battery they are still very far from giving entire satisfac- 
 tion. Practically all of them are of one kind, which is 
 
THE MODERN CLOCK. 
 
 3£' 
 
 that which produces electricity at i^^ volts from zinc, car- 
 bon and sal-ammoniac, with a depolarizer added to the 
 elements to absorb the hydrogen. The chemical action of 
 such a battery is as follows: 
 
 / 
 
 Fig. 125. 
 
 The water in the electrolite comes in contact with the zinc 
 and is decomposed thereby, the oxygen being taken from 
 the water by the zinc, forming oxide of zinc and leaving 
 the hydrogen in the form of minute bubbles attached to 
 the zinc. As this, if allowed to stand, would shut off the 
 water from reaching the zinc, chemical action would there- 
 fore soon cease and when this happens the battery is said 
 to be polarized and no current can be had from it. 
 
THE MODERN CLOCK. 
 
THE MODERN CLOCK. 383 
 
 In order to take care of the hydrogen and thus insure the 
 constant action of the battery, oxide of manganese is added 
 to the contents of the cell, generally as a mixture with the 
 carbon element. Manganese has the property of absorbing 
 oxygen very rapidly and of giving it off quite easily. There- 
 fore while the hydrogen is being formed on the zinc, it be- 
 comes an easy matter for it to leave the zinc and take its 
 proper quantity of oxygen from the manganese and again 
 form water, which is again decomposed by the zinc. As 
 long as this cycle of chemical action takes place the battery 
 will continue to give good satisfaction, and usually when a 
 battery gives out it is because the depolarizer is exhausted, 
 for the reason that the carbon is not affected at all and the 
 zinc element forming the container is present in sufficient 
 quantity to outlast the chemical action of the total mass. 
 
 There are great differences in the various makes of bat- 
 teries ; also in the methods of their construction. It would 
 seem to be an easy matter for a chemist to figure out 
 exactly how much depolarizer would serve the purpose 
 for a given quantity of zinc and carbon and therefore to 
 make a battery which should give an exact performance 
 that could be anticipated. In reality, however, this is not 
 the case, owing to the various conditions. There are three 
 qualities of manganese in the market ; the Japanese, which 
 is the best and most costly ; the German, which comes sec- 
 ond, and the American, which is the cheapest and varies in 
 quality so much as to be more or less a matter of guess- 
 work. We must remember that in making batteries for the 
 price at which they are now sold on the market we are 
 obliged to take mxaterials in commercial quantities and 
 commercial qualities and cannot depend upon the chemically 
 pure materials with which the chemists' tlieories are always 
 formulated. This therefore introduces several elements of 
 uncertainty. 
 
 In practice the Japanese manganese will stand up for a 
 far longer time than any other that is known and it is 
 
384 THE MODERN CLOCK. 
 
 used in all special batteries where quality and length of life 
 are considered of more importance than the price. The 
 German manganese comes next. Then comes a mixture of 
 American and German manganese, and finally the Ameri- 
 can manganese, which is used in making the cheaper bat- 
 teries which are sorted afterwards, as we shall explain 
 farther on. These batteries are sealed after having been 
 made in large quantities, say five thousand or ten thousand 
 in the lot, and kept for thirty days, after which they are 
 tested. The batteries which are likely to give short-life will 
 show a local action and consequent reduction of output in 
 thirty days. They are, therefore, sorted out, much as eggs 
 are candled on being received in a storage warehouse, for 
 the reason that after a cell has been made and put together 
 it would cost more to find out what was the matter with it 
 and remedy that than it would to make a new cell. Many 
 of the battery manufacturers, therefore, make up their bat- 
 teries with an attempt to reach the highest standard. They 
 are sorted for grade in thirty days and those which have 
 attained the point desired are labeled as the factories' best 
 battery and are sold at the highest prices. The others have 
 been graded down exclusively and labeled differently until 
 those which are positively known to be short-lived arc run 
 out and disposed of as the factories' cheapest product under 
 still another label. 
 
 When buying batteries always look to see that the tops 
 are not cracked, as if the seal on the cell is broken, chem- 
 ical action induced from contact with the air as the battery 
 dries out, will rapidly deteriorate the depolarizer and sul- 
 phate the zinc, both of which are of course a constant draft 
 on the life of the battery, which contains only a stated 
 quantity of energy in the beginning. Always examine the 
 terminal connections to see that they are tight and solid. 
 
 Batteries when made up are always dated by the factory, 
 but this does the purchaser little good, as the dates are in 
 codes of letters, figures, or letters and figures, and are coi?,- 
 
THE MODERN CLOCK. 385 
 
 stantly chang'ed so that even the dealers who are handling 
 thousands of them are unable to read the code. This is 
 done because many people are prone to blame the battery 
 for other defects in the electrical system and many who are 
 using great quantities would find an incentive to switch the 
 covers on which the dates appear if they knew what it 
 meant. This is perhaps rather harsh language, but a good 
 many men would be tempted to send back a barrel of old 
 batteries every now and then with the covers showing that 
 they had not lasted three months, if they could read these 
 signatures. 
 
 Practically the only means the jeweler has of obtaining a 
 good cell, with long life, is to buy them of a large electrical 
 supply house, paying a good price for them and making 
 sure that that house has trade enough in that battery to 
 insure their being continuously supplied with fresh stock. 
 
 The position of the battery also has to do with the length 
 of life or amount of its output. Thus a battery lying on its 
 side will not give more than seventy-five per cent of the 
 output of a battery which is standing with the zinc and 
 carbon elements perpendicular. Square batteries will not 
 give the satisfaction that the round cell does. It has been 
 found in practice by trials of numerous shapes and propor- 
 tions that the ordinary size of 2}^x6 inches will give 
 better satisfaction than one of a different shape — wider or 
 shorter, or longer and thinner; that is for the amount of 
 material which it contains. The battery which has proved 
 most successful in gas engine ignition work is 3^x8 
 inches. That maintains the same proportions as above, or 
 very nearly so, but owing to local action it will give on 
 clock work only about fifty per cent longer life than the 
 smaller size. 
 
 It has been a more or less common experience with 
 purchasers of electric clocks to find that the batteries which 
 came with the clock from the factory ran for two or three 
 years (three years not being at all uncommon) and that 
 
386 
 
 THE MODERN CLOCK. 
 
 they were then unable to obtain batteries which would 
 stand up to the work for more than three weeks, up to 
 six months. The difference is in the quality and freshness 
 of the battery bought, as outlined above. 
 
 In considering the rest of the electrical circuit, we find 
 three methods of wiring commonly used and also a fourth 
 which is just now coming into use. The majority of elec- 
 tric clocks are wound by a magnet which varies in size from 
 three to six ohms ; bridged around the contact points, 
 
 HM 
 
 
 RbO 
 
 w^ 
 
 Fig. 128. 
 
 Fig. 129. 
 
 there has generally been placed a resistance spool which 
 varies in size from ten to twenty-five times the number of 
 ohms in the armature magnets. See Fig. 128. This prac- 
 tically makes a closed circuit on which we are using a bat- 
 tery designed for open circuit work. 
 
 If we use an electro-magnet with a very soft iron core, 
 we will need a small amount of current, but every time we 
 break the contact, we will have a very high counter electro- 
 motive force, leaping the air gap made while breaking the 
 
 i 
 
THE MODERN CLOCK. 387 
 
 contact and therefore burning the contact points. If our 
 magnet is constructed so as to use the least current, by 
 very careful winding and very soft iron cores, this counter 
 electro-motive force will be at its greatest while the draft 
 on the battery is at its smallest. If the magnet cores are 
 rhade of harder iron, the counter electro-motive force will 
 be much less ; but on the other hand much more current 
 will be needed to do a given quantity of work with a mag- 
 net of the second description; and the consequence is that 
 while we save our contact points to some extent, we deplete 
 the battery more rapidly. 
 
 If we put in the highest possible resistance — that of air — 
 in making and breaking our contacts, we use current from 
 the battery only to do useful work; but we also have the 
 spark from the counter electro-motive force in a form 
 which will destroy our contact points more quickly. If we 
 reduce the resistance by inserting a German silver wire coil 
 of say sixty ohms on a six-ohm magnet circuit, we have 
 then with two dry batteries (the usual number) three volts 
 of current in a six-ohm magnet during work and three volts 
 of current in a sixty-six ohm circuit while the contacts are 
 broken, Fig. 128. Dividing the volts by the ohms, we find 
 that one twenty-second of an ampere is constantly flowing 
 through such a circuit. We are therefore using a dry 
 battery (an open circuit battery) on closed circuit work and 
 we are drawing from the life of our battery constantly in 
 order to save our contact points. 
 
 It then becomes a question which we are going to sacri- 
 fice, or what sort of a compromise may be made to obtain 
 the necessary work from the magnet and at the same time 
 get the longest life of the contact points and the batteries. 
 Most of the earHer electric clocks manufactured have finally 
 arranged such a circuit as has been described above. 
 
 The Germans put in a second contact between the bat- 
 tery and the resistance with a little larger angular motion 
 than. the first or principal contact, so that the contact is 
 
388 
 
 THE MODERN CLOCK. 
 
 then first made between the battery and resistance spool, B, 
 Fig. 129, then between the two contact points of the shunt, 
 A; Fig. 129, to the electro-magnet, and after the work is 
 done they are broken in the reverse order, so that the resist- 
 ance is made first and broken after the principal contact. 
 This involves just twice as many contact points and it also 
 involves more or less burning of the second contact. 
 
 
 RbO 
 
 w 
 
 
 Fig. 130. 
 
 Fig. 131. 
 
 The American manufacturers seem to prefer to waste 
 more or less current rather than to introduce additional 
 contact points, as they find that these become corroded in 
 time with even the best arrangements and they desire as 
 few of them as possible in their movements, preferring 
 rather to stand the draft on the battery. 
 
 One American manufacturer inserts a resistance spool of 
 60 ohms in parallel with a magnet of seven ohms (3^ ohms 
 for each magnet spool) as in Fig. 130. He states that the 
 counter electro-motive force is thus dissipated in the re- 
 sistance when the contact is broken, as the resistance thus 
 becomes a sort of condenser, and almost entirely does away 
 
THE MODERN' CLOCK. 389 
 
 with heating and burning of the contacts, while keeping the 
 circuit open when the battery is doing no work. 
 
 It has been suggested to the writer by several engineers 
 of high attainments and large experience that what should 
 be used in the above combination is a condenser in place of 
 a resistance spool, as there would then be no expenditure of 
 current except for work. One of the clocks changed to this 
 system just before the failure of its manufacturers, but as 
 less than four hundred clocks were made with the con- 
 densers (Fig. 131), the point was not conclusively demon- 
 strated. 
 
 It should also be borne in mind that the condenser has 
 been vastly improved within the last twelve months. With 
 the condenser it will be observed that there is an abso- 
 lutely open circuit while the armature is doing no work 
 and that therefore the battery should last that much longer, 
 Figs. 130 and 131. As to the cost of the condensers as 
 compared with resistance spools, we are not informed, but 
 imagine that with the batteries lasting so much longer and 
 the clock consequently giving so much better satisfaction, 
 a slight additional cost in manufacture by changing from 
 resistance to condensers would be welcomed, if it added to 
 the length of life and the surety of operation. 
 
 Electric clocks cost more to make than spring or weight 
 clocks and sell for a higher price and a few cents additional 
 per movement would be a very small premium to pay for an 
 increase in efficiency. 
 
 The repairer who takes down and reassembles one of 
 these clocks very often ignorantly makes a lot of trouble for 
 himself. Many of the older clocks were built in such a way 
 that the magnets could be shifted for adjustment, instead 
 of being put in with steady pins to hold them accurately in 
 place. The retail jeweler who repairs one of these clocks is 
 apt to get them out of position in assembling. The arma- 
 ture should come down squarely to the magnets, but should 
 not be allowed to touch, as if the iron of the armature 
 
390 THE MODERN CLOCK. 
 
 touches the poles of the magnet it will freeze and retain 
 its magnetism after the current is broken. Some manufac- 
 turers avoid this by plating their armatures with copper or 
 brass and this has puzzled many retailers who found an 
 electro-magnet apparently attracting a piece of metal which 
 is generally understood to be non-magnetic. 
 
 The method offers a good and permanent means of in- 
 sulating the iron of the armature from the magnet poles 
 while allowing their close contact and as the strength of a 
 magnet increases in proportion to the square of the distance 
 between the poles and the armature, it will be seen that 
 allowing the armature to thus approach as closely as pos- 
 sible to the poles greatly increases the pull of the magnet 
 at its final point. If when setting them up the magnet and 
 armature do not approach each other squarely, the armature 
 will touch the poles on one side or another and soon wear 
 through the copper or brass plating designed to maintain 
 their separation and then we will have freezing with its 
 accompanying troubles. 
 
 A very good test to determine this is to place a piece of 
 watch paper, cigarette paper or other thin tissue on the 
 poles of the magnet before the naked iron armature is 
 drawn, down. Then make the connection, hold the armature 
 and see if the paper can be withdrawn. If it cannot the 
 armature and poles are touching and means should be 
 taken to separate them. This is sometimes done by driving 
 a piece of brass into a hole drilled in the center of the pole 
 of the magnet; or by soldering a thin foil of brass on the 
 armature. As long as the separation is steadily maintained 
 the object sought is accomplished, no matter what means 
 is used to attain it. 
 
 Another point with clocks which have their armatures 
 moved in a circular direction is to see that the magnet is so 
 placed as to give the least possible freedom betv^een the 
 armatures and the circular poles of the magnet, but that 
 there must be an air-gap between the armature and magnet 
 poles. 
 
THE MODERN CLOCK. 39I 
 
 In those clocks which wind a spring by means of a lever 
 and ratchet working- into a fine-toothed ratchet wheel, or 
 are driven by a weighted lever, there is an additional point 
 to guard against. If the weight lever is thrown too far up, 
 either one of two things will happen. The weight lever 
 may be thrown up to ninety degrees and become balanced 
 if the butting post is left off or wrongly replaced ; the 
 power will then be taken off the clock, if it is driven directly 
 by weight, so that a butting post should meet the lever at 
 the highest point and insure that it will not go beyond this 
 and thus lose the efficiency of the weight. 
 
 In the cases where a spring on the center arbor is inter- 
 posed between the arbor and the ratchet wheel, it should be 
 determined just how many teeth are necessary to be oper- 
 ated when winding, as if a clock is wound once an hour 
 and the aim is to wind a complete turn (which is the amount 
 the arbor has run down) if the lever is allowed to vibrate 
 ©ne or tw^o teeth beyond a complete turn, it will readily be 
 seen that in the course of time the spring will wind itself 
 so tightly as to break or become set. This was a frequent 
 fault with the Dulaney clock and has not been guarded 
 against sufficiently in some others which use the fine ratchet 
 tooth for winding. 
 
 When such a clock is found the proper number of teeth 
 should be ascertained arid the rest of the mechanism ad- 
 justed to see that just that number of teeth will be wound 
 If less is wound there will come a time when the spring 
 will run down and the clock will stop. If too much is 
 wound the spring will eventually become set and the clock 
 will stop. Therefore such movements should be examined 
 to see that the proper amount of winding occurs at each 
 operation. Of course where a spring is wound and there 
 are but four notches in the ratchet wheel and the screw stop 
 is accurately placed to stop the action of the armature, over 
 action will not harm the spring, provided it will not go to 
 another quarter, as if the armature carries the ratchet wheel 
 
39^ 
 
 THE MODERN CLOCK. 
 
 further than it should, the smooth circumference between 
 the notches will let it drop back to its proper notch. 
 
 There are a large number of clocks on the market which 
 wind once per hour. These differ from the others in that 
 they do not depend upon a single movement of the arma- 
 ture for an instantaneous winding. Thus if the batteries 
 are weak it may take twenty seconds to wind. If the bat- 
 teries are strong and new it may wind in six seconds. In 
 this respect the clock differs radically from the others, and 
 while we have not personally had them under test, we are 
 informed that on account of winding once per hour the 
 batteries will last very much longer than would be expected 
 proportionately from those which wind at periods of greater 
 frequency. The reason assigned is that the longer period 
 allows the battery to dispose of its hydrogen on the zinc 
 and thus to regain its energy much more completely between 
 the successive discharges and hence can give a more effect- 
 ive quantity of current for hourly discharge than those 
 which are discharged several times a minute, or even sev- 
 eral times an hour. It is only proper to add that the manu- 
 facturers of clocks winding every six or seven minutes 
 dispute this assertion. 
 
 Another point is undoubtedly in the increased length of 
 life of the contacts; but speaking generally the electric 
 clock may be said now to be waiting for further improve- 
 ments in the batteries. Those who have had the greatest 
 experience with batteries, as the telephone companies, tele- 
 graph companies and other public service corporations, have 
 generally discarded their use in favor of storage batteries 
 and dynamos wherever possible and where this is not pos- 
 sible they have inspected them continuously and regularly. 
 
 In this respect one point will be found of great service. 
 When putting in a new set of batteries in any electrical 
 piece of machinery, write the date in pencil on the battery 
 cover, so that you, or those who come after you, some time 
 later, will know the exact length of time the battery has 
 
THE MODERN CLOCK. 393 
 
 been in service. This is frequently of importance, as it 
 will determine very largely whether the battery is playing 
 out too soon, or whether faults are being charged to the 
 battery which are really due to other portions of the ap- 
 paratus. 
 
 Never put together any piece of electrical apparatus with- 
 out seeing that all parts are solidly in position and are 
 clean ; always look carefully to connections and see that the 
 insulation is perfect so that short circuits will be impossible. 
 
 All contacts must be kept smooth and bright and contact 
 must be made and broken without any wavering or uncer- 
 tainty. 
 
 Fig. 132 shows the completely wired movement of the 
 American Clock Company's weight-driven movement, which 
 may be accepted as a type of this class of movements — > 
 weight-driven, winding every seven minutes. 
 
 The train is a straight-line time train, from the center 
 arbor to the dead beat escapement, with the webs of the 
 wheels not crossed out. It is wired with the wire from the 
 battery zinc screwed to the front plate H and that from 
 the battery carbon to an insulated block G. 
 
 Fig. 133 shows an enlarged view of the center arbor. 
 Upon this arbor are secured (friction tight) two seven- 
 notched steel ratchets, E, and carried loosely between them 
 are two weighted levers pivoted loosely on the center arbor. 
 Each lever is provided with a pawl engaging in the notches 
 of the nearest ratchet, as shown. The weighted lever has 
 a circular slot cut in it, concentric with the center hole and 
 also has a portion of its circumference at the arbor cut 
 away, thus forming a cam. Between these two levers is a 
 connecting link D with a pin in its upper end, which pin 
 projects into the circular slots of the weight levers. 
 
 The lever F is pivoted to the front plate of the clock and 
 carries at right angles a beveled arm which projects over 
 the ratchets E, but is ordinarily prevented from dropping 
 into the notches by riding on the circumferences of the 
 
394 
 
 THE MODERN CLOCK. 
 
 o O 
 
 CO O CO 
 
 oc 2 of 
 
 2 N CONNECTING WIRE S 
 
 jH ^rM ggw riHi'^ 
 
 Fig. 132 
 
THE MODERN CLOCK. 
 
 395 
 
 weighted levers. When one lever has dropped down and 
 the other has reached a horizontal position the cut portions 
 of the circumferences of these levers will be opposite the 
 upper notch of the ratchets and will allow the bar project- 
 
 Fig. 133 
 
 ing from F to drop into the notches. This allows F and G 
 to connect and the magnet A is energized, pulls the arma- 
 ture B, the arms C D, and thus lifts the lever through the 
 pin in D pulling at the end of the circular slot. As the 
 lever flies upward, the cam-shaped portion of its circum- 
 
39^ 
 
 THE MODERN CLOCK. 
 
 ference raises the arm out of the notches, thus separating 
 F and G and breaking the circuit. A spring placed above 
 E keeps its arms pressed constantly upon E in position to 
 drop. The wiring of the magnets is shown in Fig. 130. 
 
 The upper contact (carried in F) is a piece of platinum 
 with its lower edge cut at an angle of fifteen degrees and 
 beveled to a knife-edge. The lower point of this bevel 
 comes into contact first and is the last to separate when 
 breaking connection, so that any sparking which may take 
 place will be confined to one edge of the contacts while the 
 rest of the surface remains clean. (See Fig. 134.) Ordi- 
 
 ^^ 
 
 Fig. 134 
 
 narily there is very little corrosion from burning and this is 
 constantly rubbed off by the sliding of the surfaces upon 
 each other. The lower contact, G, consists of a brass block 
 mounted upon an insulating plate of hard rubber. The 
 block is in two pieces, screwed together, and each piece 
 carries a platinum tipped steel spring. These springs are 
 so set as to press their platinum tips against each other di- 
 rectly beneath the upper contact. The upper and lower 
 platinum tips engage each other about one-sixteenth inch at 
 the time of making contact. The lower block being in two 
 pieces, the springs may be taken apart for cleaning, or to 
 adjust their tension. The latter should be slight and should 
 
THE MODERN CLOCK. 397 
 
 in no case exceed that which is exerted by the spring in 
 F, or the upper knife-edge will not be forced between the 
 two lower springs. The pin on which F is pivoted and that 
 bearing on the spring above it must be clean and bright and 
 never he oiled, as it is through these that the current passes 
 to the upper contact in the end of F. The contacts are, of 
 course, never oiled. 
 
 The two weighted levers should be perfectly free on the 
 center arbor and their supporting pawls should be perfectly 
 free on the shoulder screws in the levers. Their springs 
 should be strong enough to secure quick action of the 
 pawls. This freedom and speed of action are important, 
 as the levers are thrown upward very quickly and may re- 
 bound from the butting post without engaging the ratchets 
 if the pawls do not work quickly. 
 
 The projecting arm, C, of the armature, B, has pivoted 
 to it, a link, D, which projects upward and supports at its 
 upper end a cross pin. The link should not be tight in the 
 slot of C, but should fit closely on the sides, in order to 
 keep the cross pin at the top of D parallel with the center 
 staff of the clock. This cross pin projects through D an 
 equal distance on either side, each end respectively passing 
 through the slot of the corresponding lever, the total length 
 of this pin being nearly equal to the distance between the 
 ratchets. When the electric circuit is closed, and the mag- 
 nets energized, B, C and D are drawn downward; the 
 weighted end of one of the levers which runs the clock, 
 being at this time at the limit of its downward movement, 
 see Fig. 135, the opposite or slotted end of said lever, is 
 then at its highest point, and the downward pull in the 
 slot by one end of the above described crosspin which en- 
 ters it will throw the weighted end of the said lever upward. 
 The direct action" of the magnets raises the lever nearly to 
 the horizontal position, and the momentum acquired carries 
 it the remainder of the distance. By this arrangement of 
 stopping the downward pull of the pin when the ascending 
 
398 
 
 THE MODERN CLOCK. 
 
 lever reaches the horizontal, all danger of disturbing the 
 other lever A is avoided. The position is such that the top 
 of the ascending lever weight is about even with the center 
 of the other weight when the direct pull ceases. 
 
 Fig. 135 
 
 Before starting the clock raise the lever weights so that 
 one lever is acting upon a higher notch of the ratchet than 
 the other. They are designed to remain about forty-five 
 degrees apart, so as to raise only one lever at each action of 
 the magnet. This maintains an equal weight on the train, 
 which would not be the case if they were allowed to rise 
 and fall together ; keeping the levers separated also reduces 
 the amount of lift or pull on the battefy and uses less cur- 
 
THE MODERN CLOCK. 399 
 
 rent, which Is an item when the battery is nearly run down. 
 If these levers are found together it indicates that the bat- 
 tery is weak, the contacts dirty, making irregular winding, 
 or the pawls are working improperly. See that the levers 
 rise promptly and with sufficient force. After one of them 
 has risen stop the pendulum and see that the butting post 
 is correctly placed, so that there is no danger of the lever 
 wedging under the post and sticking there, or causing the 
 lever to rebound too much. The butting post is set right 
 when the clock leaves the factory and seldom needs adjust- 
 ment unless some one has tinkered with it. 
 
 The time train should be oiled as with the ordinary move- 
 ments, also the pawls on the levers. The lever bushings 
 should be cleaned before oiling and then well oiled in order 
 to avoid friction on the center arbor from the downward 
 pull of the magnets when raising the levers. In order to 
 clean the levers drive out the taper pin in the center arbor 
 and remove the front ratchet, when the levers will slip off. 
 In putting them back care should be used to see that the 
 notches of the ratchets are opposite each other. Oil the 
 edges of the ratchets and the armature pins. Do not under 
 any circumstances oil the contact points, the pins or springs 
 of the bar F, as this will destroy the path of the current 
 and thus stop the clock. These pins must be kept clean 
 and bright. 
 
 Hourly Winding Clocks. — There are probably more of 
 these in America than of all other electric kinds put to- 
 gether (we believe the present figures are something like 
 135,000), so that it will not be unreasonable to give consid- 
 erable space to this variety of clocks. Practically all of 
 them ar€ made by the Self Winding Clock Company and 
 are connected with the Western Union wires, being wound 
 by independent batteries in or near the clock cases. 
 
 Three patterns of these clocks have been made and we 
 will describe all three. As they are all practically in the 
 
400 THE MODERN CLOCK. 
 
 same system, it will probably be better to first make a 
 simple statement of the wiring, which is rigidly adhered to 
 by the clock company in putting out these goods. All wires 
 running from the battery to the winding magnets of the 
 movement are brown. All wires running from the syn- 
 chronizing magnet to the synchronizing line are blue. Mas- 
 ter clocks and sub-master clocks have white wires for re- 
 ceiving the Washington signal and the relay for closing the 
 synchronizing line will, have wires of blue and white plaid. 
 
 Fig. 136 
 
 By remembering this system it is comparatively easy for 
 a man to know what he is doing with the wires, either 
 inside or outside of the case. For calendar clocks there are, 
 in addition, two white wires running from the calendar to 
 the extra cell of battery. There is also one other peculiar- 
 ity, in that these clocks are arranged to be wound by hand 
 whenever run down (or when starting up) by closing a 
 switch key, shown in Fig. 136, screwed to the inside of the 
 case. This is practically an open switch, held open by the 
 spring in the brass plate, except when it is pressed down to 
 the lower button. 
 
 The earliest movement of which any considerable number 
 were sent out was that of the rotary winding from a three- 
 pole motor, as shown in Fig. 137. Each of these magnet 
 spools is of two ohms, with twelve ohms resistance, placed 
 in parallel with the winding of each set of magnet spools, 
 thus making a total of nine spools for the three-pole 
 motor. 
 
 On the front end of the armature drum arbor is a com- 
 mutator having six points, corresponding to the six arma- 
 
THE MODERN CLOCK, 
 
 401 
 
 Fig. 137 
 
402 THE MODERN CLOCK. 
 
 tures in the drum. There are three magnets marked O, 
 P and X; each magnet has its own brush marked O', P' 
 and X'. When an armature approaches a magnet (see Fig. 
 137) the brush makes contact with a point of the com- 
 mutator, and remains in contact until the magnet has done 
 its work and the next magnet has come into action. When 
 properly adjusted the brush O' will make contact when 
 armatures i and 2 are in the position shown, with No. 2 a 
 little nearer the core of the magnet than No. i ; and it will 
 break contact when the armature has advanced into the 
 position shown by armature No. 3, the front edge of the 
 armature being about one-sixteenth of an inch from the 
 corner of the core, armature No. 4 . being entirely out of 
 circuit, as brush X' is not touching the commutator. 
 
 The back stop spring, S, Fig. 137, must be adjusted so 
 that the brush O' is in full contact with a point of the 
 commutator when the motor is at rest, with a tooth of the 
 ratch touching the end of the spring, S. 
 
 Sometimes the back stop spring, S, becomes broken or 
 bent. When this occurs it is usually from overwinding. It 
 must be repaired by a new spring, or by straightening the 
 old one by burnishing with a screwdriver. Set the spring 
 so that it will catch about half way dotvn the last tooth. 
 
 Having explained the action of the motor we come now 
 to the means of temporarily closing the circuit and keeping 
 it closed until such time as the spring is wound a suffi- 
 cient amount to run the clock for one hour; as the spring 
 is on the center arbor this requires one complete turn. 
 
 This is the distinguishing feature of this system of clocks 
 and is not possessed by any of the others. It varies in con- 
 struction in the various movements, but in all its forms it 
 maintains the essential properties of holding the current on 
 to the circuit until such time as the spring has been wound 
 a sufficient quantity, when it is again forcibly broken by the 
 action of the clock. This is termed the "knock away," and 
 exists in all of these movements. 
 
THE MODERN CLOCK. 403 
 
 To start the motor the circuit is closed by a platinum 
 tipped arm, A, Fig. 138, loosely mounted on the center 
 arbor, and carried around by a pin projecting from the 
 center wheel until the arm is upright, when it makes con- 
 tact with the insulated platinum tipped brush, B. A carries 
 in its front an ivory piece which projects a trifle above the 
 platinum top, so that when B drops off the ivory it will 
 make contact with the platinum on A firmly and suddenly. 
 This contact then remains closed until the spring barrel is 
 turned a full revolution, when a pin in the barrel cover 
 brings up the "knock away," C, which moves the arm. A, 
 forward from under the brush, B, and breaks the circuit. 
 The brush, B, should He firmly on its banking piece, and 
 should be so adjusted that when it leaves the arm. A, it will 
 drop about one-thirty-second of an inch. Adjusted in this 
 way it insures a good, firm contact. 
 
 The angle at the top of the brush, B, must not be too 
 abrupt, so as to retard the action of the clock while the 
 contact is being made. Wire No. 8 connects the spring 
 contact, B, to one of the binding plates at the left-hand 
 side of the case ; and wire No. 6 connects the motor, M, to 
 the other. To these binding plates are attached brown 
 wires that lead one to each end of the battery. 
 
 When the clock is quite run down, it is wound by press- 
 ing the switch key, Fig. 136, from which a wire runs to the 
 plate. The switch key should not be permanently connected 
 to its contact screw, J. See that all wires are in good con- 
 dition and all connections tight and bright. The main 
 spring is wound by a pinion on the armature drum arbor, 
 through an intermediate wheel and pinion to the wheel 
 on the spring barrel. 
 
 At stated times — say once in eighteen months or two 
 years — all clocks should be thoroughly cleaned and oiled, 
 and at the same time inspected to be sure they are in good 
 order. 
 
404 
 
 THE MODERN CLOCK. 
 
 Never let the self-winding clocks run down backward, 
 as the arm, A, Fig. 138, will be carried back against the 
 brush, B, and bend it out of adjustment. 
 
 Fig. 138 
 
 To clean the movement, take it from the case, take out 
 the anchor and allow it to run down gently, so as not to 
 break the piiis^ then remove the motor. Take ofif the 
 front plate and separate all the parts. Never take off the 
 back plate in these clocks. Wash the plates and all parts in 
 a good quality of benzine, pegging out the holes and let- 
 ting them dry thoroughly before reassembling. The motor 
 must not be taken apart, but may be washed in benzine, 
 by using a small brush freely about the bearings, com- 
 
THE MODERN CLOCK. 4O5 
 
 mutator and brushes. Put oil in all the pivot holes, but not 
 so much that it will run. The motor bearings and the pal- 
 lets of the anchor should also be oiled. 
 
 Inspect carefully to see that the center winding con- 
 tact is right and that the motor is without any dead points. 
 Dust out. the case and put the movement in place. Before 
 putting on the dial try the winding by means of the switch, 
 Fig. 136, to be sure that it is right; also see that the disc 
 on the cannon socket is in the right position to open the 
 latch at the hour, and after the dial and hands are on move 
 the minute hand forward past the hour and then backward 
 gently until it is stopped by the latch. This will prove 
 that the hand is on the square correctly. 
 
 On account of the liability of the motor to get out of 
 adjustment and fail to wind, from the shifting of the 
 springs and brushes, under careless adjustment, various at- 
 tempts have been made to improve this feature of these 
 clocks and the company is now putting out nearly alto- 
 gether one of the two vibrating motors, shown in Figs. 
 139 and 140. 
 
 In Style C, Fig. 139, the hourly contact for winding is the 
 same as in the clock with the three-magnet motor, as shown 
 in Fig. 138. The magnet spools are twelve ohms and the 
 resistance coil is eighty ohms, placed in parallel, as de- 
 scribed in Fig. 130. 
 
 The vibrating motor, Fig. 139, is made with a pair of 
 magnets and a vibrating armature. The main spring is 
 wound by the forward and backward motion of the arma- 
 ture, one end of the connecting rod, 8, being attached 
 to a lug of the armature, 2, and the other to the winding 
 lever, 10. This lever has spring ends, to avoid shock and 
 noise. As the winding lever is moved up and down, the 
 pawl, 9, turns the ratch wheel, 11, and a pinion on the 
 ratch wheel arbor turns the spring barrel until the winding 
 is completed. 
 
4o6 
 
 THE MODERN CLOCK. 
 
 Fig. 139 
 
THE MODERN CI>OCK, 407 
 
 The contact for operating the motor is made by the brass 
 spiral spring, 3, which is attached to the insulated stud, 4, 
 and the platinum pin, 5, which is carried on a spring at- 
 tached to the clock plate. As the armature moves forward 
 the break pin, A, in the end of the armature lifts the con- 
 tact spring, 3, thus breaking the circuit. The acquired mo- 
 mentum carries the armature forward until it strikes the 
 upper banking spring, 6, when it returns rapidly to its 
 original position, banking on spring 7, by which time con- 
 tact is again made between springs 3 and 5 and the vibra- 
 tion is repeated until the clock is wound one turn of the 
 barrel and the circuit is broken at the center winding 
 contact. 
 
 Fig. 140, Style F, is a similar motor so far as the vibrat- 
 ing armature and the winding is concerned, but the wind- 
 ing lever is pivoted directly on the arbor of the winding 
 wheel and operates vertically from an arm and stud on the 
 armature shaft, working in a fork of the winding lever, 8, 
 Fig. 140. It will be seen that the train and the motor 
 winding mechanism are combined in one set of plates. The 
 motor is of the oscillating type and its construction is such 
 that all its parts may be removed without dissembling the 
 iclock train. 
 
 Construction of the Motor. — The construction of the 
 motor is very simple, having only one pair of magnets, but 
 two sets of make and break contacts, one set of which is 
 placed on the front and the other on the back plate of the 
 movement, thus ensuring a more reliable operation of the 
 motor, and reducing by fifty per cent the possibility of its 
 failing to wind. 
 
 The center winding contact also differs from those used 
 in the three-magnet motors and former styles of vibrating 
 motor movements. The center winding contact piece, 13, 
 has no ivory and no platinum. The hourly circuit is not 
 closed by the current passing through this piece, but it acts 
 
4o8 
 
 THE MODERN CLOCK. 
 
 by bringing the plate contact spring, i6, in metallic connec- 
 tion with the insulated center-winding contact spring, .17, 
 both of which are platinum tipped. It will thus be seen 
 that no accumulation of dirt, oil or gum around the center 
 arbor or the train pivots will have any effect in preventing 
 the current from passing from the motor to the hourly cir- 
 cuit closer. 
 
 Fis. 140 
 
 The operation is as follows : As the train revolves, the 
 pin, 12, securely fastened to the center arbor, in its hourly 
 revolution engages a pin on the center winding contact 
 piece, 13. This piece as it revolves pushes the plate con- 
 tact spring, 16, upward, bringing it in metallic connection 
 with the center winding contact spring, 17, which is 
 fastened to a stud on an insulated binding post, 18, thereby, 
 closing the hourly circuit. The current passes from the 
 binding post, 18, through the battery (or any other source 
 of current supply) to binding post 19, to which is connect- 
 
THE MODERN CLOCK. 409 
 
 ed one end of the motor magnet wire. The current passes 
 through these magnets to the insulated stud, 4. To this 
 stud the spiral contact spring, 3, is fastened and the cur- 
 rent passes from this spring to the plate contact spring, 5, 
 thence through the movement plate to plate contact spring, 
 16, and from there through spring, 17, back to the battery. 
 
 The main spring is wound by the forward and backward 
 motion of the armature, 2. To this armature is connected 
 the winding lever, 8. As the winding lever is oscillated, the 
 pawl, 9, turns the ratchet wheel, 11, and a pinion on the 
 ratchet wheel arbor turns the winding wheel until the pin, 
 15, connected to it engages the knock-away piece, 14, re- 
 volving it until it strikes- the pin on the center winding 
 contact piece, 13, and pushes it from under the plate contact 
 spring, thereby breaking the electric circuit and completing 
 the hourly winding. 
 
 The proper position of the contact springs is clearly indi- 
 cated in Fig. 140. The spring, 16, should always assume 
 the position shown thereon. When the center winding 
 contact piece, 13, comes in metallic connection with the 
 plate contact spring, 16, the end of this spring should 
 stand about one-thirty-second of an inch from the edge 
 of the incline. The center winding contact spring, 17, 
 should always clear the plate contact spring one-thirty- 
 second of an inch. When the two springs touch they 
 should be perfectly parallel to each other. 
 
 Adjustments of the Armature. — In styles C and F, 
 when the armature, 2, rests on the banking spring, 7, its 
 front edge should be in line with the edge of the magnet 
 core. The upper banking spring, 6, must be adjusted so 
 that the front edge of the armature will be one-sixteenth of 
 an inch from the corner of the magnet core when it touches 
 the spring. 
 
 When the contact spring, 3, rests on the platinum pin, 5, 
 it should point to about the center of the magnet core, with 
 
4IO THE MODERN CLOCK. 
 
 the platinum pin at the middle of the platinum piece on the 
 spring. 
 
 To adjust the tension of the spiral contact spring, 3, take 
 hold of the point with a light pair of tweezers and pull it 
 gently forward, letting it drop under the pin. It should 
 take the position shown by the dotted line, the top of the 
 spring being about one-thirty-second of an inch below the 
 platinum pin. If from any cause it has been put out of ad- 
 justment it can be corrected by carefully bending under the 
 tweezers, or the nut, 4, may be loosened and the spring 
 removed. It may then be bent in its proper shape and 
 replaced. 
 
 The hole in the brass hub to which the spring is fastened 
 has a flat side to it, fitting a flat on the insulated contact 
 stud. If the contact spring is bent to the right position it 
 may be taken off and put back at any time without chang- 
 ing the adjustment, or a defective spring may readily be 
 replaced with a new one. When the armature touches the 
 upper banking spring the spiral contact spring, 3, should 
 clear the platinum pin, 5, about one-sixteenth of an inch. 
 Both contacts on front and back plates in style F are ad- 
 justed alike. The circuit break pins "A" on the armature 
 should raise both spiral contact sprmgs at the same instant. 
 
 If for any reason the motor magnets have become dis- 
 placed they may readily be readjusted by loosening the 
 four yoke screws holding them to the movement plates. 
 Hold the armature against the upper banking spring, move 
 the magnets forward in the elongated slot, 20, until the 
 ends of the magnet cores clear the armature by one-sixty- 
 fourth of an inch, then tighten down the four yoke screws. 
 Connect the motor to the battery and see that the arma- 
 ture has a steady vibration and does not touch the magnet 
 core. The adjustment should be such that the armature 
 can swing past the magnet core one-eighth to three-six- 
 teenths of an inch. 
 
THE MODERN CI.OCK. 4II 
 
 Description of Synchronizer. — At predetermined 
 times a current is sent through the synchronizer magnet, 
 D', Fig. 141, which actuates the armature, E, to which arc 
 attached the levers, F and G, moving them down until tlic 
 points on the lever, G, engage with two projections, 4 and 
 5, on the minute disc; and lever F engages with the 
 heart-shaped cam or roll on the seconds arbor sleeve, 
 causing both the minute and second hands to point to XII. 
 These magnet spools are wound to twelve ohms, w^ith an 
 eighty-ohm resistance in parallel. 
 
 On the latch, L, is a pin, I, arranged to drop under the 
 hook, H," and prevent any action of the synchronizing 
 levers, except at the hour. A pin in the disc on the can- 
 non socket unlocks the latch about two minutes before the 
 hour and closes it again about two minutes after the signal. 
 This is to prevent any accidental ''cross" on the synchron- 
 izing line from disturbing the hands during the hour. 
 
 AI is a Hght spring attached to the synchronizing frame 
 to help start the armature back after the hands are set. 
 The wires from the synchronizing magnet are connected to 
 binding plates at the right-hand side of the clock and from 
 these binding plates the blue wires, Nos. 9 and 10, pass out 
 at the top of the case to the synchronizing line. 
 
 If the clock gets out of the synchronizing range it gen- 
 erally indicates very careless regulation. The clock is regu- 
 lated by the pendulum, as in all others, but there is one 
 peculiarity in that the pendulum regulating nut has a 
 check nut. 
 
 If the clock gains time turn the large regulating nut 
 under the pendulum bob slightly to the left. 
 
 If the clock loses time turn the nut slightly to the 
 right. 
 
 Loosen the small check nut under the regulating nut 
 before turning the regulating nut, and be sure to tighten 
 the check nut after moving the regulating nut. 
 
412 
 
 THE MODERN CLOCK. 
 
 Fig. 141 
 
THE MODERN CLOCK. 413 
 
 The friction of the seconds hand is very carefully ad- 
 justed at the factory, being weighed by hanging a small 
 standard weight on the point of the hand. If it becomes 
 too light and the hand drives or slips backward, losing 
 time, it can be made stronger by laying it on a piece of 
 wood and rubbing the inner sides of the points with a 
 smooth screw driver, and if too heavy and the clock will 
 not set when the synchronizing magnets are actuated, the 
 points of the spring in the friction may be straightened a 
 little. 
 
 If the seconds hand sleeve does not hold on the seconds 
 socket, pinch it a little with pliers. If the seconds hand is 
 loose on the sleeve put on a new one or solder it on the 
 under side. 
 
 In style F the synchronizing lever, heart-shaped sec- 
 onds socket and cams on the cannon sockets are the same 
 as in the old style movements, shown in Fig. 141. The 
 difference is in the synchronizing magnets and the way 
 they operate the synchronizing lever. The magnet has 
 a flat ended core instead of being eccentric like the former 
 ones. The armature is also made of flat iron and is pivoted 
 to a stud fastened to the synchronizing frame. The arma- 
 ture is connected to the synchronizing lever by a connect- 
 ing rod and pitman screws. A sector has an oblong slot, 
 allowing the armature to be lowered or raised one-six- 
 teenth of an inch. The synchronizing lever is placed on a 
 steel stud fastened to the front plate and held in position 
 by a brass nut. The synchronizing magnets are 12 ohms 
 with 80 ohms resistance and are fastened to a yoke which 
 is screwed to the synchronizing frame by four iron screws. 
 The holes in the synchronizing frame are made oblong, 
 allowing the yoke and magnets to be raised or lowered one- 
 sixteenth of an inch. The spring on top of the armature 
 is used to throw it back quickly and also acts as a diamag- 
 netic, preventing the armature from freezing to the mag- 
 nets. A screw in the stud is used to screw up against the 
 
414 THE MODERN CLOCK. 
 
 magnet head, preventing any spring that might take place 
 on the armature stud. Binding posts are screwed to the 
 synchronizing frame and the ends of the magnet coils are 
 fastened thereto with metal clips. 
 
 The blue wires in the clock case are coiled and have a 
 metal clip soldered to them.* They connect direct by these 
 clips to the binding posts, thus making a firm connection, 
 and are not liable to oxidize. With the various points of 
 adjustment a pair of magnets burned out or otherwise 
 defective may readily be replaced in from five to ten min- 
 utes. 
 
 When replacing a pair of synchronizing magnets pro- 
 ceed as follows : Remove the old pair and then loosen all 
 four screws in the yoke, pushing it up against the tops 
 of the oblong holes, then tighten down lightly. Fasten the 
 new pair of magnets to the yoke with the inner ends of 
 the coils showing at the outside of the movement. Press 
 the armature upward until the synchronizing lever locks 
 tightly on the cannon socket and the heart-shaped cams, 
 then loosen the magnet yoke screws and press the magnets 
 down on the spring on top of the armature. Then tighten 
 the yoke screws on the front plate and see that the back 
 of the magnets clears the armature by one-hundredth of 
 an inch (the thickness of a watch paper), when the screws 
 in the back of the yoke can be set down firmly. The ad- 
 justment screw may then be turned up until it presses 
 lightly against the magnet head. When current is passed 
 through the magnets and held there the armature must 
 clear the magnets without touching. The magnet coils 
 must then be connected to their respective binding posts by 
 slipping the metal clips soldered to them under the rubber 
 bushing, making a metallic connection with the binding 
 plates. Fasten these screws down tight to insure good 
 connections. 
 
THE MODERN CLOCK, 
 
 415 
 
 The Master Clock. — Is a finely finished movement 
 with mercurial pendulum that beats seconds and a Gerry 
 gravity escapement. At the left and near the center of the 
 movement is a device for closing the synchronizing circuit 
 
 /O^ 
 
 Fig. U2 
 
 once each hour. The device consists of a stud on which 
 is an insulator having two insulated spring fingers, C and 
 D, one above the other, as shown in Fig. 142, except at 
 the points where they are cut away to lie side by side on 
 an insulated support. On these fingers, and near the 
 insulator, are two platinum pieces, E and F, so adjusted 
 
4l6 THE MODERN CLOCK. 
 
 as to be held apart, except at the time of synchronizing. 
 
 A projection, B, from the insulator rests on the edge 
 of -a disc on the center arbor. At ten seconds before the 
 hour, a notch in this disc allows the spring to draw the 
 support downward, leaving the points of the fingers, C 
 and D, resting on the raised part of the rubber cam on 
 the escape arbor. The end of the finger, C, is made 
 shorter than that of D, and at the fifty-ninth second, C 
 drops and closes the circuit by E striking F. At the 
 next beat of the pendulum the long finger D drops and 
 opens the circuit again. 
 
 The winding is the same as in the regular self-winding 
 clocks, the motor wire and seconds contact being con- 
 nected to the binding plates at the left, from which 
 brown wires lead up to the battery. Two wires from the 
 synchronizing device are connected to the binding plates 
 at the left, from which blue wires run out to the line. 
 
 Before connecting the clock to the line it must be run 
 until it is well regulated, and also to learn if the con- 
 tacts are working correctly. Regulate at first by the 
 nut at the bottom of the rod until it runs about one 
 second slow in 24 hours (a full turn of the nut will 
 change the rate about one-half miniite per day). The 
 manufacturers send with each clock a set of auxiliary 
 pendulum weights, the largest weighing one gram, the 
 next in size five decigrams and the smallest two deci- 
 grams; these weights are to make the fine regulations by 
 placing one or more of them on the little table that is 
 fastened about the middle of the pendulum rod. The five 
 decigram weight will make the clock gain about one 
 second per da}^, and the other weights in proportion. 
 Care must be taken not to disturb the swing of the 
 pendulum, as a change of the arc changes the rate. 
 
 To start the clock after it is regulated, stop it, with 
 the second hand on the fiftieth second; move the hands 
 forward to the hour at which the signal comes from the 
 
THE MODERN CLOCK. 
 
 ^'7 
 
 observatory; then press the minute hand back gently un- 
 til it is stopped by the extension on the hour contact, 
 Fig. 142, and beat the clock up to the hour. This ensures 
 the hour contact being in position to send the synchronize 
 ing signal. 
 
 A good way to start it with observatory time is with 
 all the hands pointing to the "signal" hour; hold the 
 pendulum to one side and when the signal comes let it 
 go. With a little practice it can be started very nearly 
 correct. 
 
 Clocks not lettered in the bottom of the case must be 
 wound before starting the pendulum. To do this press 
 the switch shown in Fig. 136, which is on the left side 
 of the case and under the dial. 
 
 Continue the pressure until the winding ceases. Then 
 set the hands and start the pendulum in the usual way. 
 If the bell is not wanted to ring, bend back the hammer. 
 
 Secondary Dials. — One of the most deceptive branches 
 of clock work is the secondary dial, or "minute jumper." 
 Ten years ago it was the rule for all manufacturers of elec- 
 tric clocks to put out one or more patterns of secondary 
 dials. Theoretically it was a perfect scheme, as the sec- 
 ondary dial needed no train, could be cheaply installed and 
 could be operated without trouble from a master clock, so 
 that all dials would show exactly the same time. Practical- 
 ly, however, it proved a very deceptive arrangement. The 
 clocks were subject to two classes of error. One was that it 
 was extremely difficult to make any mechanical arrangement 
 in which the hands would not drive too far or slip backward 
 when the mechanism was released to advance the minute 
 hand. The second class of errors arose from faulty con- 
 tacts at the master clock and variation in either quantity 
 or strength of current. Another and probably the worst 
 feature was that all such classes of apparatus record their 
 own errors and thereby themselves provide the strongest 
 
4lS THE MODERN CLOCK. 
 
 evidence for condemnation of the system. Clocks could be 
 wound once an hour with one-sixtieth of the chance of error 
 of those wound once per minute, and they could be wound 
 hourly and synchronized daily with i-i440th of the line 
 troubles of a minute s}^stem. 
 
 The minute jumpers could not be synchronized without 
 costing as much to build and install as an ordinary self- 
 winding clock, with pendulum and time train, and after try- 
 ing them for about ten years nearly all the companies have 
 substituted self-winding time train clocks with a synchron- 
 izing system. They have apparently concluded that, since 
 it seems too much to expect of time apparatus that it will 
 work perfectly under all conditions, the next thing to do is 
 to make the individual units run as close to time as is com- 
 mercially practicable and then correct the errors of those 
 units cheaply and quickly from a central point. 
 
 It is for these reasons that the secondary dial has prac- 
 tically disappeared from service, although it was at one time 
 in extensive use by such companies as the Western Union 
 Telegraph Company, the Postal Telegraph and the large 
 buildings in which extensive clock systems have been in- 
 stalled. 
 
 Fig. 143 shows one form of secondary dial which in- 
 volves a screw and a worm gear on the center arbor, which, 
 it will be seen, is adapted to be turned through one minute 
 intervals without the center arbor ever being released from 
 its mechanism. This worm gear was described in the 
 American Jeweler about fifteen years ago, when patented 
 by the Standard Electric Time Company in connection with 
 their motor-driven tower clocks, and modifications of it have 
 been used at various times by other companies. 
 
 The worm gear and screw system shown in Fig. 143 has 
 the further advantage that it is suitable for large dials, as 
 the screw may be run in a box of oil for dials above four 
 feet and for tower clocks and outside work. This will read- 
 ily be seen to be an important advantage in the case of large 
 
THE MODERN CLOCK. 
 
 419 
 
 hands when they arc loaded with snow and ice, requiring- 
 more power to operate them. 
 
 All secondaries operate by means of an electromagnet 
 raising a weight, the weight generally forming the armature ; 
 the fall of the weight then operates the hands by gravity. 
 
 Fig.143. Minute jumper. A, armature; M, magnets; "W, worm gear on 
 center arbor ; B, oil box for worm ; R, four toothed ratchet. 
 
 Direct action of the current in such cases is impracticable, 
 as the speed of starting with an electric current would 
 cause the machine to tear itself to pieces. 
 
 This screw gear is the only combination known to us that 
 will prevent the hands from slipping or driving by and re- 
 duces the errors of the secondary system to those of one 
 class, namely, imperfections in the contact of the master 
 clock, insufficient quantity or strength of current, or acci- 
 dental "crosses" and burnings. 
 
 The series arrangement of wiring secondaries was for- 
 merly greatly favored by all of the manufacturers, but it 
 
420 
 
 THE MODERN CLOCK. 
 
 was found that if anything happened to one clock it stopped 
 the lot of them; and where more than fifty were in series, 
 the necessary voltage became so high that it was impractica- 
 ble to run the clocks with minute contacts. The modern 
 system, therefore, is to arrange them in multiples, very much 
 after the fashion of incandescent lamps, then if one clock 
 goes wrong the others are not affected. Or if the current 
 is insufficient to operate all, only those which are farthest 
 away would go out of time. 
 
 Very much smaller electromagnets will do the work than 
 are generally used for it, and the economy of current in 
 such cases is worth looking after, as with sixty contacts per 
 "hour batteries rapidly play out if the current used is at all 
 excessive. Where dry batteries are used on secondaries 
 care should be taken to get those which are designed for gas 
 engine ignition or other heavy work. Wet batteries, with 
 the zincs well amalgamated, will give much better satisfac- 
 tion as a rule and if thp plant is at all large it should be oper- 
 ated from storage cells with an engineer to look after the 
 battery and keep it charged, unless current can be taken 
 from a continuously charged lighting main. This can be 
 readily done in such instances as the specifications call for in 
 the new custom house in New York, namely, one master 
 clock and i6o secondary dials. 
 
 Electric Chimes. — There have lately come into the mar- 
 ket several devices for obtaining chimes which allow the 
 separation of the chimes and the timekeeping apparatus, 
 connection being made by means of electricity. In many 
 respects this is a popular device. It allows, for instance, a 
 full set of powerful tubular chimes, six feet or more in 
 length, to be placed in front of a jewelry store, where they 
 offer a constant advertisement, not only of the store itself, 
 but of the fact that chiming clocks may be obtained there. 
 It also allows of the completion by striking of a street clock 
 which is furnished with a time train and serves at once as 
 
THE MODE KM CLOCK. 
 
 421 
 
 timepiece and sign. ]\lany of these have tubular chimes in 
 which the hour bell is six feet in length and the others cor- 
 respondingly smaller. They have also been made with bells 
 of the usual shape, which are grouped on posts, or hung in 
 
 Fig. 144. Cbimes of beUs in rack. 
 
 Fig. 145. Chimes of bells with resonators. 
 
 racks and operated electrically. It may also be used as a 
 ship's bell outfit by making a few minor changes in the con- 
 troller. 
 
 Fig. 144 shows a peal of bells in which the rack is thirty- 
 six inches long and the height of the largest bell is eight 
 inches, and the total weight thirty pounds. This, as will 
 readily be seen, can be placed above a doorway or any other 
 convenient position for operation ; or it may be enclosed in 
 a lattice on the roof, if the building is not over two stories 
 in height. The lattice work will protect the bells from the 
 weather and at the same time let out the sound. 
 
 Fig. 145 shows the same apparatus with resonators at- 
 tached. These are hollow tubes which serve as sounding 
 boards, largely increasing the sound and giving the effect 
 
422 
 
 THE MODERN CLOCK. 
 
 of much larger bells. Fig. 146 shows a tubular chime and 
 the electrical connections from the clock to the controller 
 and to the hammers, which are operated by electro-magnets, 
 so that a heavy leaden hammer strikes a solid blow at the 
 tops of the tubes. 
 
 ^.^^'i!=^:;^^^^^^^;x3^ ^^ 
 
 THF.W.GR£ENELEaRlcCQ^ 
 
 "IMPERIAL" 
 
 WuTMINSTERflETRICCHIflETIIBB 
 
 U 
 
 rr"--"i 
 
 u 
 
 Hi 
 
 I 
 
 i 
 
 CkECTKIC J 
 CONTROLLER 
 
 
 
 y?^^ 
 
 Fig. 146, Tubular electric chimes. 
 
 The dials of such clocks contain electrical connections and 
 the minute hand carries a brush at its outer end. The con- 
 tact is shown in enlarged view in Fig. 147, by which it will 
 be seen that the metal is insulated from the dial by means 
 of hard rubber or other insulating material, so that the 
 brush on the minute hand wall drop suddenly and firmly 
 from the insulator to the metallic contact when the minute 
 hand reaches fifteen, thirty, forty-five or sixty minutes. 
 There is a common return wire, either screwed to the frame 
 of the clock, or attached to the dial, which serves to close 
 
THE MODERN CLOCK. 423 
 
 the various circuits and to give four strokes of the chimes at 
 the quarter, eight at the half, twelve at the three-quarter, 
 and sixteen at the hour, followed by the hour strike. The" 
 friction on the center arbor is of course adjusted so as to 
 carry the minute hand without slipping at the contacts. 
 
 By this means a full chime clock may be had at much less 
 cost than if the whole apparatus had to be self-contained and 
 the facilities of separation between the chimes and the time- 
 keeping apparatus, as hinted above, gives many advantages. 
 
 
 Fig. 147. Enlarged view of connections on dial. 
 
 For instance, the same clock and controller may operate 
 tubes inside the room and bells outside, or vice versa. These 
 are operated by wet or dry batteries purchased at local 
 electrical supply houses, and the wiring is done with plain 
 covered bell wire, or they may be operated by current from 
 a lighting circuit, suitably reduced, if the current is con- 
 stantly on the mains. As a full chime with sixteen notes 
 at the hour strikes more than a thousand times a day, con- 
 siderable care should be taken to obtain only the best bat- 
 teries where these are used, as after the public gets used 
 to the chimes the dealer will be gre:itly annoyed by the 
 number of people asking for them if they are stopped tem- 
 porarily. 
 
 There has lately developed a tendency to avoid tlic set 
 tunes, such as the Westminster and the Wliittington chimes, 
 and to sound the notes as complete full notes, such as the 
 first, third and fifth of the octave for the first, second and 
 third quarters, followed by the hour strike. This allows 
 
424 THE MODERN CLOCK. 
 
 them to be struck in any order and for a smaller chime re- 
 duces the cost considerably. The tubes used are rolled of 
 bell metal and vary in pitch with the manufacture,- so that 
 the only way to obtain satisfactory tones is to cut your tubes 
 a little long and then tune them by cutting ofif afterwards, 
 
 /6 C/fimes ar7c/y,^^f^^^^ ^^^^^^^^anJ Connect/nn 
 /}Oc/r ^^^^^^/^^^^^\^ *^0 1 II #^^>VA^;'^/W around 
 
 /^^\ All / ^^'' ^/^/ 
 
 Fig. 148. Connections and contacts on front of clock dial. 
 
 the tone depending upon the thickness of. the wall' of the 
 tube and its length. The bells are tuned by turning from 
 the rim or from the upper portions as it is desired to raise 
 or lower the tone, and if the resonators are used they are 
 tuned in unison with the bells. 
 
 Of the ordinary bells, Fig. 144, the dimensions run: 
 First, height four inches, diameter ^Yi ; second, height four 
 inches, diameter 5J4 inches ; third, height 4^ inches, diam- 
 eter 5^ inches; fourth, height 4j/^ inches, diameter 5^ 
 inches; fifth, height 4^ inches, diameter 63^ inches. For 
 
THE MODERN CLOCK. 
 
 425 
 
 the tubes the approximate length is six feet for the longest 
 tube and the total weight of the chimes is 43 pounds. 
 For the controller the size is nine by eleven by six inches, 
 
 I 
 
 1 
 I 
 
 
 I I I I 
 
 ® ® (9) ^ 
 
 
 ■//7<su/ofed 
 
 9- 
 
 Fig. 149. Connections and wiring on back of clock dial. 
 
 with a weight of ten pounds. The hour strike may be had 
 separately from the chimes if desired. 
 
 This makes an easily divisible system and one that is be- 
 coming very popular with retail jewelers and to some ex- 
 tent with their customers. 
 
CHAPTER XXII. 
 
 THE CONSTRUCTION AND REPAIR OF DIALS. 
 
 Probably no portion of the clock is more important than 
 the dial and it is apparently for this reason that we find so 
 little variation in the marking. The public refuses to ac- 
 cept anything in the way of ornamentation which interferes 
 with legibility and about all that may be attempted is a lit- 
 tle flat ornament in light colors which will not obscure the 
 sight of the hands, as it is in reality the angle made by the 
 two hands which is read instead of the figures. In proof 
 of this may be cited the many advertising dials in which 
 one letter takes the place of each character upon the dial 
 and of the tower clocks in which the hours are indicated 
 merely by blackened characters, being nothing less than an 
 oblong blotch on the dial. Thousands of people will pass 
 such a dial without ever noticing that the regular charac- 
 ters do not appear. Various attempts have been made to 
 change the colors and the sizes and shapes of the characters 
 but comparatively few are successful. A black dial with 
 gold characters and hands is generally accepted, or a cream 
 dial with black hands, but any further experiments are 
 dangerous except in the cases of tower clocks, which may 
 have gold hands on any light colored dial, or a glass dial. 
 In all such cases legibility is the main factor nought and 
 the bright metal is far plainer for hands and chapters than 
 anything that may be substituted for them. 
 
 In tower clocks the rule is to have one foot of diameter 
 of the dial for every ten feet of height. Thus a clock situ- 
 ated one hundred feet above the ground level should have a 
 
 4.6 
 
THE MODERN CLOCK. 427 
 
 ten foot dial. On very large dials this rule is deviated from 
 a little, but not much. All dials, except those of tower 
 clocks, should be fastened to the movement, rather than to 
 the case. This is particularly true where a seconds hand, 
 with the small opening for the seconds hand sleeve, makes 
 any twisting or warping of the case and consequent shift- 
 ing of the dial liable to rub the dial against the sleeve at the 
 seconds hand and thus interfere with the timekeeping. 
 
 The wTiter has in mind a case in which a large number 
 of fine clocks w^ere installed in a new brick and stone build- 
 ing. They were finely finished and no sooner had they been 
 hung on the damp w^alls than the cases commenced to swell 
 and twist. It was necessary three times to send a man to 
 move the dials which had been attached to these clocks. 
 As there were about thirty clocks it will be seen that this 
 was expensive. After the walls had dried out the cases be- 
 gan to go back to the positions in which they were origin- 
 ally, as the moisture evaporated from the cases, and the 
 dials had consequently to be moved through another series. 
 All told it took something like a week's work for one man 
 to shift these dials half a dozen times during the first nine 
 months of their installation. If these dials had been fas- 
 tened on pillars on the movements, the shrinking and swell- 
 ing of the cases would not have afifected them. 
 
 It is for this reason that dials are invariably fastened on 
 the movements of all high class clocks. 
 
 The characters en clock dials are still very largely 
 Roman, the numerals being known as chapters. Attem.pts 
 have been recently made to substitute Arabic figures and in 
 such cases the Arabic figures remain upright throughout the 
 series, while the chapters invariably point the foot of the 
 Roman numeral toward the center of the dial. This makes 
 the Roman numerals from IIII to VIII upside down, Vv^hile 
 in the Arabic numerals this inversion dees net cccr.r. 
 
 The propcrtions [^cneral-v ca:ictio"cd by usage have been 
 found, after measuring clock dials, all the Vv^ay from two 
 
428 THE MODERN CLOCK. 
 
 to eighteen inches, and may be given in the following terms : 
 With a radius of 26 mm. the minute circle is i^ mm. The 
 margin between minute circles and chapters is i mm. The 
 chapters are 8^ mm. The width of the thick stems of the 
 letters are ^4 rnm. The width of an X is 4 mm. and the 
 slanting of X's and V's is twenty degrees from a radius of 
 the dial. The letters should be proportioned as follows: 
 The breadth of an Tand a space should equal one-half the 
 breadth of an X, that is, if the X is one-half inch broad, the 
 I will be three-sixteenths inch broad and the space between 
 letters one-sixteenth inch, thus making the I plus one space 
 equal to one-quarter inch or half the breadth of an X. The 
 V's should be the same breadth as the X's. After the let- 
 ters have been laid off in pencil, outline them with a ruHng 
 pen and fill in with a small camel's hair brush, using gloss 
 black paint thinned to the proper consistency to work well 
 in the ruling pen. Using the ruling pen to outline the let- 
 ters gives sharp straight edges, which would be impossible 
 with a brush in the hands of an inexperienced person. 
 
 For tower clocks the chapters and minutes together will 
 take up one-third of the radius of the dial ; the figures two- 
 thirds of this, or two-ninths of the radius, and the minutes 
 two-thirds of the remaining one-ninth of the radius, with 
 every fifth minute more strongly marked than the rest. 
 
 We often hear stories concerning the IIII in place of IV. 
 The story usually told is that Louis XIV of France was in- 
 specting a clock made for him by a celebrated watchmaker 
 of that day and remarked that the IV was an error. It 
 should be IIII. There was no disputing the King and so 
 the watchmaker took away the dial and had the IIII en- 
 graved in place of IV, and that it has thus remained in de- 
 fiance of all tradition. 
 
 Mr. A. L. Gordon, of the Seth Thomas Clock Co., has 
 the following to say concerning this story and thus fur- 
 nishes the only plausible explanation we have ever seen for 
 
THE MODERN CLOCK. 429 
 
 the continuance of this manifest error in the Roman num- 
 eral of the dial : 
 
 "That the attempt has been made to use the IV for the 
 fourth hour on clock dials, any one making a study of them 
 may observe. The dials on the Big Ben clock in the tower 
 of the Parliament buildings, London, which may be said to 
 be the most celebrated clock in the world, have the IV 
 mark, and the dial on the Herald building in New York 
 City also has it. 
 
 "That the IIII mark has come to stay all must admit, 
 and if so there must be a good and sufficient reason. Art 
 writers tell us that pictures must have a balance in the plac- 
 ing and prominence of the several subjects. Most conven- 
 tional forms are equally balanced about a center line or a 
 central point. Of the latter class the well known trefoil is 
 a common example. 
 
 "A clock or watch dial with Roman numerals has three 
 points where the numerals are heavier, at the IIII, VIII 
 and XII. Fortunately these heavier numerals come at 
 points equally spaced about the center of the dial and about 
 a center line perpendicular to the dial. Of these three heavy 
 numerals the lighter of them comes at the top and it is 
 especially necessary that the other two, which are placed at 
 opposite points in relation to the center line, should be bal- 
 anced as nearly as possible. As the VIII is the heavier 
 and cannot be changed, the balancing figure must be made 
 to correspond as nearly as possible, and if marked as IV, 
 it will not do so nearly as effectively as if the usual IIII is 
 used." 
 
 It is comparatively an easy matter to make a metal dial 
 either of zinc, copper or brass, by laying out the dial as in- 
 dicated above with Roman chapters and numerals, after 
 first varnishing the metal with asphaltum. This may be 
 drawn upon with needle points which cut through the 
 asphaltum and make a firmly defined line on the metal. It 
 is best to lay out your dial in lead pencil and then take a 
 
430 THE MODERN CLOCK. 
 
 metal straight edge and a needle point and trace through 
 on the pencil marks. Mistakes may be painted out with 
 asphaltum, so that the job becomes easy. After this has 
 been done a comparatively dull graver may be used to cut 
 or scrape away the asphaltum wdiere the metal is to be 
 etched and then the plate may be laid in a tray, a solution 
 of chloride of iron poured on and rocking the tray will 
 rapidly eat away the metal, forming sunken lines wherever 
 the copper or brass is" not protected by the asphaltum. This 
 furnishes a rough surface on the etched portions, which en- 
 ables the filling to stick much better than if it were smooth. 
 In tracing the circles a pair of heavy, stiff, carpenters' com- 
 passes will serve where the watchmaker has not a lathe 
 large enough to swing the dial. In all such cases it is best 
 to start with a prick-punched center, tracing the minute 
 circles and the serifs of the chapters with the compasses and 
 then do your further division and marking by lead pen- 
 cil, followed with the needle and then by the acids. It 
 should be done before the holes are bored for the minute 
 and seconds centers, as you then have an exact center to 
 mark from and can go back to it many times. 
 
 This will be necessary in 'dividing the minute or seconds 
 circle by hand (without an index on the lathe), as one of 
 the tests of true division consists in having all marks lined 
 up with a straight edge placed across the center. Thus IX 
 and III should be in line with the center; VI and XII; X 
 and IIII; I and VII, etc. It will readily be seen that for 
 such purposes of reference the center should not be punched 
 too large. 
 
 If it is desirable to ornament the dial, the desired orna- 
 ment may be drawn on in the plain surface through the 
 asphaltum and etched at the same time as the chapters and 
 degrees. Or chapters and ornament may be drawn, pierced 
 with a saw, engraved, filed up and backed up with a plain 
 plate of another color. Gold ornament and silver back- 
 ground looks well. 
 
THE MODKKN CLOCK. 43I 
 
 Practically all the clocks having seconds hands carry that 
 hand in such a position as to partially obscure the XII, 
 with the exception of watchmakers' regulators, and these, 
 if they have separate hour, minute and seconds circles, are 
 made large enough to occupy the space between the center 
 and the minute circle, placing the hour circle between the 
 center and the thirtieth minute ; 'the seconds between the 
 .center and the sixtieth minute. The reason for this is that 
 in^the watchmakers' regulators the hours are almost a mat- 
 ter of indifference ; minutes are reldom referred to ; the real 
 coniparison in watch regulation comes on the seconds hand. 
 For this reason the seconds hand is made as large as pos- 
 sible and the chapters being placed on the hour circle by 
 themselves, the seconds circle may occupy almost the en- 
 tire distance between the center of the dial and the minute 
 circle. They are placed one above the other because in 
 regulators the tim.e train is nearly always a straight-line 
 train, which brings the seconds arbor vertically over the 
 center arbor, and consequently the centers of the dials must 
 be placed on a vertical line. 
 
 When the engraving has been properly done on a flat 
 dial it is desirable to fill it with black in order to make it 
 legible. There are several methods by which this may be 
 done. The most durable is to make a black enamel and if 
 it is a valuable clock the movement is generally worth a fine 
 dial. The following formula will furnish a good black 
 enamel : 
 
 Siliceous sand 12 parts 
 
 Calcined borax 20 parts 
 
 Glass of antimony 4 parts 
 
 Saltpetre 1 part 
 
 Chalk 2 parts 
 
 Peroxide of Manganese 5]/2 parts 
 
 Fine Saxony Cobalt 2 parts 
 
 The enamel is ground into coarse particles like sand, and 
 the incised lines filled with it, after which the brass or cop- 
 
432 THE MODERN CLOCK. 
 
 per plate is heated red hot to fuse the enamel. Two or 
 three firings may be necessary to completely fill the lines ; 
 after filling they arc stoned off level with the surface of the 
 dial. Jeweler's enamel may be purchased of material deal- 
 ers and used for the dials. 
 
 Black asphaltum mixed with a little wax or pitch, or even 
 watchmakers' cement, used to fasten staffs and pinions 
 into a lathe for turning, is also used on these dials and with 
 a sufiicient proportion of wax or pitch it prevents shrinking 
 and forms a very satisfactory dial with the single exception 
 that it cannot be cleaned with benzine or hot potash, which 
 will dissolve the enamel. Shoemakers' heel ball is also used 
 for repair jobs. In order to make either of these stick, the 
 brass or copper plate is heated up so as to "hiss" as will a 
 laundry flat iron when touched with a wetted finger, and 
 a cement stick is rubbed over the letters to fill them; the 
 excess of filling can be scraped off with an ivory scraper 
 when at the right temperature — a little below the boiling 
 point of water. Such filled letters can be lacquered over by 
 going very quickly over the work so as not to dissolve the 
 shellac in the cement. 
 
 Another way is to fill the letters with black lacquer. For 
 quick repairs this is probably as good as any. Many of the 
 old grandfather clocks have been filled in with a putty made 
 with copal varnish and some black pigment. All putties 
 shrink in drying and consequently crack and finally fall out. 
 The wax and pitch are not subject to these disadvantages. 
 If the plates are to be polished, polishing should precede 
 the filling in of the letters, else the work may have to be 
 done all over again. Black sealing wax and alcohol are also 
 used, applied as a paint w^th a fine brush. 
 
 If the dial is to be silvered or gilt the blacking should be 
 done first, and if to be electroplated the blacking should be 
 what is known as the "platers' resist," which is composed 
 chiefly of asphaltum and pitch dissolved in turpentine. It 
 is also called "stopping-off" varnish, and has large use in 
 
THE MODERN CLOCK. 433 
 
 the plating establishments to prevent deposition of metal 
 where it is not desired. 
 
 The repairer who gets many grandfather clocks will 
 often find that it is necessary to repaint the dial, generally 
 because of a too vigorous scrubbing, or because of crack-; 
 or scaling, which the owner may dislike. It is always best, 
 however, to be cautious in such matters, as many people 
 value such a clock chiefly on account of its visible evidences 
 of age and such cracks form generally a large proportion 
 of such evidence. Therefore it is best never to touch an 
 antique dial unless the owner desires it. 
 
 Such dials are usually sheet-iron, and tolerably smooth, 
 so the metal will need but a few coats of paint to prepare it. 
 For ground coats, take good, ordinary white-lead or zinc 
 white, ground with oil, and if it has much oil mixed with it 
 pour "it off and add spirits of turpentine and Japan dryer — 
 a teaspoonful of dryer for every half pint of paint.. The 
 test for the paint having the right amount of oil left in it is, 
 it should dry without any gloss. Rub every coat you apply 
 with fine sand-paper, after it is perfectly dry, before apply- 
 ing the next coat of paint. For the final coat, lay the dial 
 flat and go over it with French zinc-white. This coat dries 
 very slow, and for a person not used to such work, is hard 
 to manage. The next best (and for ordinary clock or watch 
 making the best) for the last pure white coat is to take a 
 double tube of Windsor & Newton's Kremnitz white, 
 thinned wath a little turpentine. Such tubes as artists use 
 are the kind. Apply this last w^hite coat with a flat, camel's 
 hair brush. The tube-white should have turpentine enough 
 added to cause it to flow freely, and sink flat and smooth 
 after the brush. The letters or figures should be painted 
 with ivory-black, which is also a tube color. This black is 
 mixed with a little Japan, rubbing-varnish and turpentine, 
 and the lettering is done with a small, sign waiter's pencil. 
 Any flowers or ornaments are painted on at the same time ; 
 and after they are dry the dial should be varnished with 
 
/|34 '^^^ MODERN CLOCK. 
 
 Mastic or Damar varnish or white shellac. All kinds of 
 coach (Copal) varnish are too yellow. 
 
 . Painted dials on zinc will blister and crack off if sub- 
 jected to extremes of heat and cold, unless they are painted 
 with zinc white instead of lead for all white coats. The rea- 
 son is the great difference in expansion between lead paint 
 and metallic zinc. This case is similar to that of using an 
 iron oxide to paint iron work of bridges, ships, etc., where 
 other oxides will chip and scale off. 
 
 The metal dials on these old clocks were silvered by 
 hand. When you get such a dial, discolored and tarnished, 
 it can be. cleaned in cyanide and resilvered, without sending 
 it to an clectroplater, by the following formula : 
 
 Dissolve a stick of nitrate of silver in half a pint of rain 
 water; add two or three tablespoonfuls of common salt, 
 which will at once precipitate the silver in the form- of a 
 thick, white curd, called chloride of silver. Let the chloride 
 settle until the liquid is clear; pour off the water, taking 
 care not to lose any chloride ; add more water, thoroughly 
 stir and again pour off, repeating till no trace of salt or acid 
 can be perceived by the taste. After draining off the water 
 add to the chloride about two heaped tablespoonfuls each 
 of salt and cream of tartar, and mix thoroughly into a paste, 
 which, when not in use, must not be exposed to the light. 
 To silver a surface of engraved brass, wash the curface 
 clean with a stiff brush and soap. Heat it enough to melt 
 black sealing wax, which rub on with a stick of wax until 
 the engraving is entirely filled, care being taken not to burn 
 the wax. With a piece of flat pumice-stone, and some pul- 
 verized pumice-stone and plenty of water, grind off the 
 wax until the brass is exposed in every part, the stoning 
 being constantly in one direction. Finish by laying an even 
 and straight grain across the brass with blue or water of 
 Ayr stone. Take a small quantity of pulverized pumice- 
 stone on the hand, and slightly rub in the same direction, 
 which tends to make en even rT:rain ; the hands mmi be 
 
THE .MODERN CLOCK. 435 
 
 entirely free from soap or grease. Rinse the brass thor- 
 oughly, and before it dries, lay it on a clean board, and 
 gently rub the surface with fine salt, using a small wad of 
 clean muslin. When the surface is thoroughly covered with 
 salt, put upon the wad of cloth, done up with a smooth sur- 
 face, a sufficient quantity of the paste, say to a dial three 
 inches in diameter a piece of tlie size of a marble, wdiich 
 rub evenly and quickly over the entire surface. The brass 
 will assume a greyish, streaked appearance ; add quickly to 
 the cloth cream of tartar moistened with water into a thin 
 paste ; continue rubbing until all is evenly whitened. Rinse 
 quickly under a copious stream of water ; and in order to 
 dry it rapidly, dip into water as hot as can be borne by the 
 hands, and when heated, holding the brass by the edges, 
 shake off as much of the water as possible, and rem.ove any 
 remaining drops with clean, dry cloth. The bra^s should 
 then be heated gently over an alcohol lamp, until the wax 
 glistens without melting, when it may be covered with a 
 thin coat of spirit varnish, laid on with a broad camel's 
 hair brush. The varnish or lacquer must be quite light- 
 colored — diluted to a pale straw color. 
 
 It is now possible to buy silver plating solutions which 
 can be used without battery and they will produce the same 
 effect as the formula just given. If they happen to be in 
 stock for the repairing of jewelry they may be used in 
 cleaning the dials, but as this is liable to fall into the hands 
 of many wdio are far from such conveniences, we furnish 
 the original recipe, which can be executed anywhere the 
 materials can be obtained. 
 
 If the dial is of brass, very good effects have been pro- 
 duced by stopping off portions of the dial in an ornamental 
 pattern before silvering, and then lacquering after removing 
 the resist. But for a plain black and brass dial a dip of 
 strong sulphuric acid two parts, red fuming nitrous acid 
 one part, and water one part, mixed in the open air and 
 dipped or flowed over the dial, forms what is known as the 
 
436 THE MODERN CI-OCK. 
 
 platers' bright dip. After dipping the article should at once 
 be rinsed in hot water and dried, and lacquered at once with 
 a' lacquer of light gold color. This makes a very neat and 
 durable finish. 
 
 The satin effect may be obtained on a dial by prolonging 
 the acid dip and otherwise proceeding as before. Many of 
 these dials were of zinc and all that applies to brass or cop- 
 per may be also executed in zinc, but in plating it will be 
 found necessary to plate two or three times, as the single 
 coating will apparently disappear into the zinc unless it is 
 given a heavy deposit of copper in a plating bath. Where 
 it is desired to obtain a bright gold color, the gold plating 
 solutions now sold for the coloring of jewelry may also be 
 used on either of these metals. For the reasons given 
 above, however, they are not very successful on a zinc 
 base. 
 
 Many of the cheap clocks have paper dials glued on a 
 zinc plate and when the dial is soiled the repairer cleans 
 them up by pasting another dial on top of the original. 
 These dials are made on what is known as lithographic label 
 paper: that is paper which is waterproof on one side, so 
 that it will not shrink or swell when dampened. In addition 
 to the lithograph coating they are generally given a varnish 
 of celluloid by the clock manufacturers, thus making them 
 practically waterproof. They are very cheap and the re- 
 pairer will find that he will obtain in prestige from such 
 new dials far more than they cost. 
 
 Tarnished metal dials are best cleaned by a dip of cyanide 
 of potassium, of about the same strength as that used for 
 cleaning silver. If the tarnished parts have been gilded, 
 however, the cyanide should be excessively weak. Mining 
 men use a cyanide solution for the recovery of gold, which 
 is only two-tenths of one per cent cyanide, and this will 
 collect all the gold from ore that runs from $10 to $15 to 
 the ton, the pulp in such cases being left in the solution 
 from seventy to ninety hours. The ordinary cyanide dip 
 
THE MODERN CLOCK. 437 
 
 for the jeweler is one ounce to thirty-two of water, while 
 the miner's solution is two-tenths of an ounce to one hun- 
 dred ounces of water. You can see that with the strong 
 cyanide solution the gilt surface will all be taken off unless 
 very rapid dipping is strictly followed by thorough wash- 
 ing. 
 
 A novelty which keeps periodically coming to the front, 
 say about once every ten years, is the luminous dial. This 
 is done by painting the dial with phosphorus or a phos- 
 phorescent powder. Then when it is placed in the light it 
 will absorb light and give it off in the dark until the evap- 
 oration of the phosphorus. 
 
 The composition and manufacture of this phosphores- 
 cent powder is effected in the following manner: Take 
 100 parts by weight of carbonate of lime and phosphate 
 of lime, produced by calcination of sea-shells, especially 
 those of the tridacna and cuttlefish bone, and lOO parts by 
 weight of lime, rendered chemically pure by calcination. 
 These ingredients are well miixed together, after which 25 
 parts of calcinated sea salt are added thereto, sulphur being 
 afterward incorporated therewith to the extent of from 25 
 to 50 per cent of the entire mass, and a coloring matter is 
 applied to the composition, which coloring matter consists 
 of from 3 to 7 per cent of the entire mass of a pow^der com- 
 posed of a mono-sulphide of calcium, barium, strontium, 
 magnesium or other substance which has the property of 
 becoming luminous in the dark, after having been impreg- 
 nated with light. After these ingredients are well mixed, 
 the composition is ready for use. Its application to clock 
 dials is made either by incorporating suitable varnish there- 
 with, such as copal, and applying the mixture with a brush 
 to the surface of the dial, or by the production of a dial 
 which has a self-luminous property, imparted to it during 
 its manufacture. This is effected in the following manner : 
 From 5 to 20 per cent of the composition obtained and 
 formed as above described, is incorporated with the glass 
 
438 THE MODERN CLOCK. 
 
 while it is in a fused state, after which the glass so pre- 
 pared is molded or blown into the shape or article required. 
 Another process consists of sprinkling a quantity of the 
 composition over the glass article while hot, and in a semi- 
 plastic state, by either of which processes a self-luminous 
 property will be imparted to the article so treated. 
 
 Where enamel dials are chipped the cracks may be hidden 
 by first pressing the cracks very slightly open and washing 
 out. Then work in a colorless cement to fill the crack, allow 
 to dry and stone down. Where holes have been left by the 
 chipping, melt equal parts of scraped pure white wax and 
 zinc white and let it cool. Warm the dial slightly and press 
 the cold wax into the defective places and scrape off with a 
 sharp knife and it will leave a white and lustrous surface. 
 If too hard add wax ; if too soft add some zinc white. 
 
 Varnish for Dials, Etc. — A handsome varnish for the 
 dials of clocks, watches, etc., may be prepared by dissolving 
 bleached shellac in the purest and best alcohol. It offers 
 the same resistance to atmospheric influence that common 
 shellac does. In selecting bleached shellac for this purpose 
 be careful to get that which will dissolve in alcohol, as some 
 of it being bleached with strong alkalies, is thereby rendered 
 insoluble in alcohol. The shellac when dissolved should 
 be of a clear light amber color in the bottle and this will be 
 invisible on white paper when dry. 
 
 Colorless celluloid lacquer, known to jewelers as "silver 
 lacquer" on account of its being used to prevent tarnish on 
 finished hollow ware, also makes a good varnish to apply 
 to dials, either metallic or painted. It is best to have it 
 thin, flow it on the dial and then level the dial to dry. 
 
 Success in the repairing of a broken enameled clock dial 
 will greatly depend upon the practical skill of the operator, 
 as well as of a knowledge of the process. If it is only de- 
 sired to repair a chipped place on a dial, a fusible enamel of 
 the right tint should be procured from a dealer in watch- 
 
THE MODERN CEOCK. 439 
 
 makers' materials, which, with ordinary care, may be fused 
 on the chipped place on the dial so as to give it a workman- 
 like appearance when finished off. The place to receive the 
 enamel should be well cleaned, and the moist enamel spread 
 over the place in a thin, even layer; and, after allowing it 
 to dry, the dial may be held over a spirit lamp until the new 
 enamel begins to fuse, when it may be smoothed down with 
 a knife. The dial, after this operation, is left to cool, when 
 any excess of enamel may be removed by means of a corun- 
 dum file, and subsequently polished with putty powder 
 (oxide of tin). The ingredients of enamel, after being 
 fused into a mass, are allowed to cool, then crushed to 
 powder and well washed to get rid of inpurities, and the re- 
 sulting fine powder forms the raw material for enameling. 
 It is applied to the object to be enameled in a plastic con- 
 dition, and is reduced to enamel by the aid of heat, being 
 .first thoroughly dried by gentle heat, and then fused by a 
 stronger one. The following is a good white enamel for 
 dials : 
 
 Silver sand, 3 ounces ; red lead, 3^ ounces ; oxide of tin, 
 2.y2 ounces ; saltpeter, ^ ounce ; borax, 2 ounces, flint glass, 
 I ounce ; manganese peroxide, 2 grains. The basis of nearly 
 all enamels is an easily fusible colorless glass, to which the 
 required opacity and tints are given by the addition of var- 
 ious metallic oxides, and these, on being fused together, 
 form the different kinds of vitreous substances used by 
 enamel workers as the raw material in the art of enameling. 
 
 The hands of timekeepers are worthy of more attention 
 than is frequently bestowed upon them by watch and clock- 
 makers. Their shape and general arrangement, and the 
 neatness of their execution is often taken by the general 
 public as an index to the character of the entire mechanism 
 that moves them; and some are apt to suppose that when 
 care is not bestowed on the parts of the time-piece which 
 are most seen, much care cannot be expected to have been 
 exercised on the parts of the watch or clock which are in- 
 
440 THE MODERN CLOCK. 
 
 visible to the general view. Although we are not prepared 
 to fully endorse the opinion that when the hands of time- 
 pieces are imperfect in their execution, or in their general 
 arrangem.ent, all the mechanism must of necessity be im- 
 perfect also; still we think that in many instances there is 
 room for improving the hands of timepieces, and we desire 
 to direct more attention to this subject by the workmen. 
 
 In the general arrangement of the hands of watches and 
 clocks, distinctness of observation should be the great point 
 aimed at, and everything that has a tendency to lead to con- 
 fusion should be carefully avoided. Clocks that have a 
 number of hands radiating from one center, and moving 
 round one circle — as for instance, center seconds, days of 
 the month, equation of time, alarms and hands for other 
 purposes — may show a good deal of mechanical skill on the 
 part of the designer and maker of the timepiece ; but so 
 many hands moving together around one circle, although 
 they may be of different colors, causes confusion, and re- 
 quires considerable effort to make out what the different 
 hands point to in a dim light, and this confusion is fre- 
 quently increased by the necessity for a counterpoise being 
 attached to some of the hands. As a rule timekeepers should 
 be so arranged that never more than the hour and minute 
 hand should move from one center on the dial. There may 
 be special occasions when it is necessary or convenient to 
 have center seconds to large dials ; but these occasions are 
 rare, and we are talking about the hands of timekeepers 
 in every-day use for the ordinary purposes of life, and also 
 for scientific uses. In astronomical clocks and watchmakers' 
 regulators we find the hour, minute and second hands mov- 
 ing on separate circles on the same dial ; and the chief rea- 
 son for this arrangement is to prevent mistakes in reading 
 the time. In chronometers, especially those measuring- side- 
 real time, the hour hand is frequently suppressed, and the 
 hours are indicated by a star wheel, or ring, with figures 
 engraved on it, that show through a hole in the dial. 
 
THE MODE UN CLOCK. 
 
 ^41 
 
 Hour and minute hands should be shaped so that the one 
 can be easily distinguished from the other without any ef- 
 fort on the part of the observer. Probably a straight minute 
 hand, a little swelled near the point, and a spade hour hand, 
 are the shapes best adapted for this purpose, especially if 
 the hands have to be looked at from a distance. There are 
 occasions, however, when a spade hand cannot be used with 
 propriety. In small watches and .clocks having ornamental 
 cases, hands of other designs are desirable, but whatever 
 be the pattern used, or whatever color the hands m.ay be 
 made, it should ever be remembered that wdiile a design in 
 harmony with the case is perfectly admissible, the sole use 
 of hands is to mark the time distinctly and readily. 
 
 The difference in the length of the hour and minute hands 
 is also an important point in rendering the one easily dis- 
 tinguished from the other. The extreme point of the hour 
 hand should extend so as to just cover the edge of the in- 
 side end of the numerals and the extreme point of the 
 minute hand should cover about two-thirds of the length of 
 the minute divisions. Hands made of this length will be 
 found to mark the hours and minutes with great plainness, 
 and the rule will be found to work well in dials of all sizes. 
 As a general rule, the extreme points of the hands should 
 be narrow. The point of the hour hand should never be 
 broader than the thickest stroke of any of the numerals, 
 and the extreme point of the minute hand never broader 
 than the breadth of the minute lines ; and in small work it is 
 well to file the ends of the hands to a fine point. The ends 
 of minute hands should in every instance be bent into a 
 short, graceful curve pointing toward the dial, and as close 
 to it as will just allow the point of the hand to be free. The 
 minute hands of marine chronometers are invariably bent 
 in this manner, and the hands of these instruments are 
 usually models of neatness and distinctness. 
 
 Balancing hands by means of a counterpoise is a subject 
 which requires some attention in order to effect the perfect 
 
442 THE MODERN CLOCK. 
 
 poise of the hand without detracting anything from its dis- 
 tinctness. In watch work, and even in ordinary clock- work, 
 it seldom happens that any of the hands except the seconds 
 require to be balanced, and then there is only one hand mov- 
 ing round the same circle, as is the case with seconds hands 
 in general. We have become so accustomed to looking at 
 seconds hands with projecting tails that we are apt to re- 
 gard the appearance of the hands to be incomplete without 
 the usual tail ; but we must remember that the primary ob- 
 ject in view in having a tail to a seconds hand is to counter- 
 poise it, not to improve the looks of the hand itself. Poising 
 becomes an actual necessity for a hand placed on so sensi- 
 tive a part as the fourth wheel of a watch, or on the scape 
 wheel of a fine clock. When only one hand moves in the 
 same circle, like a seconds hand, the counterpoise may be 
 effected by means of a projecting tail without in any way 
 detracting from a distant reading of the hands, providing 
 the tail is not made too long, and it is made of such a pat- 
 tern that the one end can easily be distinguished from the 
 other. In minute and hour hands, however, it is different. 
 These two hands move round the same circle, and a coun- 
 terpoise on the minute hand is liable at a distance to be mis- 
 taken for the hour hand. 
 
 The minute hands of large timepieces frequently require 
 to be balanced, especially if the dial be large in comparison 
 to the size of the movement; and in very large or tower 
 clocks, whatever may be the size of the movement, it be- 
 comes an absolute necessity to balance the hands. In our 
 opinion, tails should never be made on minute hands, when 
 they can be avoided, and in cases where tails cannot be dis- 
 pensed with, they should invariably be colored the same as 
 the ground of the dial. In almost every instance, however, 
 minute hands may be balanced in the inside, as is usual with 
 tower clocks. A great many clocks used for railway and 
 similar purposes in Europe have their minute hands bal- 
 anced in this manner, and the plan works admirably ; for in 
 
THE MODERN CLOCK. 
 
 443 
 
 Fig. 150. Showing counterpoise on arbor of minute hand in tower clock. 
 
444 THE MODERN CLOCK. 
 
 addition to rendering the hands more distinct, the clocks re- 
 quire less power to keep them going than when the hands 
 are balanced from the outside. 
 
 Tower clock hands are generally made of copper, elliptical 
 in section, being made up of two circular segments brazed 
 together at the edges, with internal diaphragms to stiffen 
 them. The minute hand is straight and perfectly plain, with 
 a blunt point. At the center of the dial the width of the 
 minute hand is one-thirteenth of its length, tapering to 
 about half as much at the point. 
 
 The hour hand is about the same width, ending jus|: short 
 of the dial figure and terminating in a palm or ornament. 
 The external counterpoises are one-third the length of the 
 minute hand, and of such a shape that they will not be con- 
 founded with either of the hands ; a cylinder, painted the 
 same color as the dial, and loaded with lead, makes a good 
 counterpoise. This counterpoise may be partly on the in- 
 side of the dial if it is desired to keep it invisible, but it 
 should not be omitted, as it saves a good deal of power, pre- 
 vents the twisting of the arbors, and also assists in over- 
 coming the action of the wind on the hands. Two-thirds 
 of the counterpoise weight may be inside, as shown in Fig. 
 150. 
 
 To Blue a Clock Hand or a Spring. — To blue a piece 
 of steel that is of some length, a clock hand for example, 
 clockmakers place it either on ignited charcoal, with a hole 
 in the center for the socket, and whitened over its surface, 
 as this indicates a degree of heat that is approximately uni- 
 form, or on a curved bluing tray perforated with holes 
 large enough to admit the socket. The center will become 
 violet or blue sooner than the rest, and as soon as it assumes 
 the requisite tint, the hand must be removed, holding it with 
 tweezers by the socket, or by the aid of a large sized arbor 
 passed through it ; the lower side of the hand is then placed 
 on the edge of the charcoal or bluing tray, and removed by 
 
THE MODERN CLOCK. 445 
 
 gradually sliding it off toward the point, more or less slowly, 
 according to the progress made with the coloring; with a 
 little practice, the workman will soon be enabled to secure 
 a uniform blue throughout the length and even, if necessary, 
 to retouch parts that have not assumed a sufficiently deep 
 tint. 
 
 Instead of a bluing tray, a small mass of iron, with a 
 slightly rounded surface and heated to a suitable tempera- 
 ture, can be employed ; but the color must not form too 
 rapidly, and this is liable to occur if the temperature of the 
 mass is excessive. Nor should this temperature be unevenly 
 distributed. 
 
 A spring, after being whitened, can be blued in the same 
 way. Having fixed one end, it is stretched by a weight at- 
 tached to the other end^ and the hot iron is then passed 
 along it at such a speed that a uniform color is secured. Of 
 course, the hot iron might be fixed and the spring passed 
 over it. A lamp may be used, but its employment involves 
 more attention and dexterity. 
 
CHAPTER XXIII. 
 
 CLOCK CASING AND CASE REPAIRS. 
 
 Precision Clock Cases. — The casing of a precision 
 clock is uiily secondary in importance to the comoensation 
 of its pendulum. The best construction of an efficient case 
 can be ascertained only by most careful study of the con- 
 ditions under which the clock is expected to be a standard 
 timekeeper, and often the entire high accuracy sought by re- 
 fined construction is sacrificed by an inefficient case and 
 mounting. 
 
 The objects of casing a precision clock are as follows 
 
 a. To protect the mechanism from the effects of dust 
 and dirt, 
 
 b. To avoid changes of temperature and barometric 
 pressure. 
 
 c. To provide an enclosed space in which the gas me- 
 dium in which the pendulum swings shall have any chem- 
 ical constitution, of any hygroscopic condition. 
 
 d. There must be provided ready means of seeing and 
 changing the condition of the pendulum, electric apparatus, 
 movement, etc., without disturbing the case except locally. 
 
 Now if we hold the above considerations in view we can 
 readily see that cast iron, wood and glass, with joints of 
 wash leather (which is kept soft by a wax cement which 
 does not become rancid with age), are the preferable ma- 
 terials. 
 
 The advantages of using cast iron for the pillar or body 
 of the case are that it can b'e cast in such a shape as to re- 
 quire very little finishing afterwards, and that only such 
 as planing parallel surfaces in iron planing machines. It 
 
 446 
 
THE MODKI^N CLOCK:. 
 
 447 
 
 makes a stiff column for mounting the pendulum when it 
 rests upon a masonry foundation from below. Plates of 
 glass can be clamped against the planed surfaces of iron 
 piers (by putting waxed wash leather between the glass and 
 the iron) so as to make air-tight joints without difficulty. 
 
 The mass' of iron symmetrically surrounding the steel 
 pendulum is the safest protection the clock can have against 
 casual magnetic disturbances. In the language of elec- 
 tricians it ''shields" the pendulum^. 
 
 Suppose, then, we adopt as the first type of precision 
 clock case which our present knowledge suggests, that of an 
 Iron cylinder or rectangular box resting on a m.asonry pier, 
 and which has a table top to which the massive pendulum 
 bracket is firmly bolted. This type admits of the weights 
 being dropped in small cylinders outside of the cast iron 
 cylinder or box. These weight cylinders, of course, end In 
 the table top of the clock case above and in the projecting 
 base of the flange of the clock case below. 
 
 With this construction it is a simple matter to cover the 
 movement with a glass case, preferably made rectangular, 
 with glass sides, ends and top, with rtietal cemented joints. 
 The metal bottom, edges of this rectangular box can be 
 ground to fit the plane surface of the top of the clock case. 
 Then, by covering the bottom edges with such a wax as was 
 used in making the glass plates fit the iron case in front or 
 back, we can secure an air-tight joint at the junction of the 
 rectangular top glass case wath iron case. In practice the 
 W2LX to be used may be made by melting together and stir- 
 ring equal parts of vaseline and beeswax. The proportions 
 may be varied to give a different consistency of wax, and It 
 may be painted on with a brush after warming over a small 
 flame. 
 
 If the clock case will be exposed to a comparatively high 
 temperature, say 95° F., then the beeswax can be 3 parts to 
 I of vaseline. The good quality of this cement wax Is that 
 it does not change with age, or at least for several years. 
 
448 THE MODERN CLOCK. 
 
 is very clean, and can be wiped off completely with kerosene, 
 or turpentine, or benzine. In all joints meant to be air-tight, 
 the use of rubber packing is to be avoided. It answers well 
 enough at the start, but after several months it is sure to 
 crack and leak air. 
 
 By an air-tight joint I do not mean a joint which will not 
 leak air under any pressure w^hich may be applied. It is not 
 necessary that our pendulum should vibrate in a vacuum; 
 all we want is that the pressure inside the clock case should 
 be uniform ; that it should not vary with the barometer out- 
 side. In actual practice we find it best to iTave the pressure 
 inside the case as nearly as possible equal to the average 
 atmospheric pressure outside. Now, if the barometer in a 
 given locality never sinks below 27.5 inches, it is not neces- 
 essary that the vacuum in the clock case be less than that 
 represented by 29.5 inches of mercur)- pressure. So, too, 
 if it were desirable to have the pressure inside the case great- 
 er than that outside, owing to some special form of joint 
 which made the clock case less liable to leak out than to 
 leak in, it might be that an inside pressure would be effi- 
 cient at 31 inches of mercury. By not having the inside 
 pressure vary but slightly from the outside, the actual pres- 
 sure of air will not exceed one inch of mercury, or, say, 
 y2 pound pressure to the square inch. This is a pressure 
 which causes quite an insignificant strain upon any joint. 
 
 There are objections, however, to the use of air in an en- 
 closed space for precision clocks and so the attempt has been 
 made to tise hydrogen. Air is, comparatively speaking, 
 heavy. It is 14 J/2 times as heavy as hydrogen gas, for in- 
 stance. The pendulum, therefore, in moving through its 
 arc has to push aside 14 times as much weight as it would 
 have to in case it were surrounded by hydrogen. Then 
 what might be called the ''case friction" is greater than if 
 we used hydrogen. By "case friction" I mean resistance 
 and a disturbance to the pendulum depending on the effect 
 of the currents of air produced by driving the air before the 
 
THE MODERN CLOCK. ^/^g 
 
 pendulum against the sides and front of the case. It is 
 a well-established observation that small, cramped cases dis- 
 turb the clock's rate more than large, roomy ones. This is 
 because the air, having no room to go before the pendulum, 
 is cushioned up against the side of the case at each pendu- 
 lum swing, and acts as a resisting spring against the swing 
 of the pendulum. By the time the pendulum has reached 
 the end of its vibration the air has escaped upwards and 
 downwards perhaps so that it no longer has its spring power 
 to restore the loss of energy to the pendulum. This "case 
 friction" is most pernicious in its action when associated 
 with free falling weights in the clock case. Clock weights 
 should always fall in separate compartments, and never in 
 such a manner that they can affect the space in which the 
 pendulum swings. 
 
 But this is a digression to explain the term "case friction" 
 in its use in horology. 
 
 Precision clocks, almost without exception, have electric 
 break-circuit attachments within -the case. Most of these 
 break-circuits are constructed so that there is a small spark 
 every time the circuit is broken. The effect of such a spark 
 in air is to convert a small portion of the air in the imme- 
 diate neighborhood of the spark into nitrous acid gas. 
 After several months there might be a considerable quantity 
 of this gas in the case, with the certain result of rusting the 
 nicer parts of the escapement. 
 
 Many attempts have been made to run a clock in an 
 almost complete vacuum of air; but the volume to be ex- 
 hausted is so large, and the leakage is so sure to occur after 
 a time, that the attempt is now pretty generally abandoned. 
 It will be inferred from what has preceded that a full atmos- 
 phere of hydrogen would only offer one-fourteenth the re- 
 sistance to the pendulum that air would, and all the disturb- 
 ances arising from the surrounding mediums would be only 
 one-fourteenth for hydrogen of that which we would ex- 
 pect for air. Every consideration, therefore points to the 
 
45© THE MODERN CLOCK. 
 
 use of hydrogen as the medium with which to fill our clock 
 cases. It is inert, it forms no compounds under the influ- 
 ence of the electric spark, the case friction is no greater 
 than would exist if we made an air vacuum of only about i 
 inch of mercury, and hydrogen gas may be readily prepared. 
 The method from dilute sulphuric acid and scrap zinc is the 
 handiest, and it will be found described in almost any chem- 
 istry textbook or encyclopedia. Should the horolo- 
 gist wish to know something of the chemistry of 
 the process, without pervious study, he will find 
 it described in very simple language in any pri- 
 mary chemistry. The practical details of filling a clock 
 case with hydrogen gas I have not yet worked out. It is 
 evident that since hydrogen is 143^ times lighter than 
 air, that by attaching a small tube to the source of hydrogen 
 and to the top of the clock case, and another small outlet 
 tube at the bottom of the clock case, that by gravity alone 
 the hydrogen would fill the upper part of the case and drive 
 the air before it out at the bottom. The hydrogen should 
 be dry. To insure this it should pass through a tube con- 
 taining quicklime, which, if it is a foot long and two inches 
 in diameter, will be sufficient. No burning light or electric 
 spark must be put into the case while filling, because the 
 mixture of hydrogen with the air is very explosive when 
 ignited. Great care must be used in making all joints 
 when attempting to maintain an atmosphere of hydrogen 
 as it leaks readily through the pores of wood iron and all 
 joints. It is, therefore, better to treat the case friction as 
 a constant element and simply keep it constant. 
 . The above discussion has not considered the temperature 
 question. It is important that the changes of temperature 
 in a clock case should be as slow as possible and as small as 
 possible. Professor Rogers, of the Harvard College Ob- 
 servatory, has shown that such bars as are used in pendu- 
 lum rods of clocks are often several hours in taking up 
 air temperatures m.any degrees different from that in which 
 
THE MODERN CLOCK. 45I 
 
 they were swinging. We have at the top of the pendulum 
 a thin spring for suspension whose temperature decides 
 its molecular friction ; then we have the pendulum rod, and 
 lastly the large bob, all of which take up any new tempera- 
 ture with different degrees of slowness. Now obviously no 
 compensation can be made to act unless the temperatures are 
 the same for all parts of the pendulum, and vary at the 
 same rate. A number of years ago, there was a long discus- 
 sion as to the temperature at the top and bottom of clock 
 cases. It was shown that this regularly amounted to several 
 deofrees in the best clocks. It was to lessen this difference 
 that at the Harvard College Observatory the Bonds built a 
 deep well in the cellar, purposing to put the clock at its 
 bottom. The idea was a good one, and were it not for the 
 difficulty in getting at clocks in wells, and keeping water 
 out, it would doubtless find favor where the*utm.ost accu- 
 racy is desired. 
 
 A better plan is to run the clock at a high temperature, 
 say 95° to 100° F. The oil is more liquid, the temperature 
 can be more easily maintained, it can all take place in light- 
 ed, dry rooms, and the means for doing this we shall now 
 consider. 
 
 Our iron case must now be housed in another outside 
 case, which had better be of wood, with glass windows for 
 seeing the clock face. A single thickness of wood would 
 conduct heat too rapidly. It must therefore be made of 
 two thicknesses, with an air space between. If the air 
 space is left unfilled, the circulation of the air soon causes 
 the inner wooden layer to be of the same temperature as the 
 outer. It is necessary to prevent this circulation of air 
 therefore by means of some substance which is a non-con- 
 ductor of heat and which will prevent the air from circu- 
 lating. The very best thing to be used in this connection is 
 cotton batting, which has been picked out until it is as light 
 and fibrous as possible. Then if the doors and windows 
 of the Vv'ooden case are made of two thicknesses of extra 
 
452 
 
 THE MODERN CLOCK. 
 
 thick glass, and are firmly clamped, by screws through their 
 sashes or some other means, to the frame of the case, we 
 have the best form possible for our completed case of the 
 type I have described. It now remains to provide a layer 
 of hot water pipes inside the clock room, heated by circula- 
 ting hot water from the outside. The flame under the 
 
 DDDiDDnlDDDlDDDlnDnlDDDlODDlDDdDDDlDgDlDDD 
 
 I . I I . I ."m 
 
 1 r 
 
 HESSiigaaSiSBigiBBlESslB) 
 
 Fig. 151. Section tlirough dock room of the Waltliam Watcli Company 
 
 water tank outside, whether of gas or kerosine, to be auto- 
 matically raised or lowered by any such thermostat arrange- 
 ments as are in common use with chicken incubators, when 
 the temperature varies from the point desired. Experience 
 teaches that the volume of water had better be considerable, 
 if there is considerable difference in the annual variations of 
 temperature according to the seasons. Thus in Massa- 
 
THE MODERN' CLOCK. 453 
 
 chnsetts or Illinois the temperature is likely to vary irom 
 — 30° F. to + 110° F., and the heating arrangements must 
 be suitable to take care of this variation. 
 
 The Waltham Watch Company's clock room is an excel- 
 lent example of the means taken to secure uniformity of 
 temperature and absence of vibration. 
 
 The clock room, which is located in the basement of one 
 of the buildings, is built with a double shell of hollow tile 
 brick. The outer shell rests upon the floor of the basement, 
 and its ceiling is within two or three inches of the base- 
 ment ceiling. The inner shell is lo feet square and 8 feet 
 in height, measured from the level of the cellar floor. There 
 is an i8-inch space between the walls of the inner and outer 
 shell and a 9-inch space between the two ceilings. On the 
 front of the building the walls are three feet apart to ac- 
 commodate the various scientific instruments, such as the 
 chronograph, barometer, thermostat, level-tester, etc. The 
 inner house is carried down four feet below the floor of the 
 basement, and rests upon a foundation of gravel. The walls 
 of the inner house below the floor level consist of two thick- 
 nesses of brick with an air space between, and the whole 
 of the excavated portion is lined, sides and bottom, with 
 sheet lead, carefully soldered to render it watertight. At 
 the bottom of the excavation is a layer of 12 inches of sand, 
 and upon this are built up three solid brick piers, meas- 
 uring 3 feet 6 inches square in plan by 3 feet in height, 
 which form the foundation for the three pyramidal piers 
 that carry the three clocks. The interior walls and ceilings 
 and the piers for the clocks are finished in white glazed 
 tiling. The object of the lead lining, of course, is to thor- 
 oughly exclude moisture, while the bed of sand serves to 
 absorb all waves of vibration that are communicated 
 through the ground from the various moving machinery 
 throughout the works. At the level of the basement floor a 
 light grating provides a platform for the use of the clock 
 attendants. 
 
454 THE MODERN CLOCK. 
 
 Although the placing of the clock room in the cellar and 
 the provision of a complete air space around the inner room 
 would, in itself, afford excellent insulation against external 
 changes of temperature, the inner room is further safe- 
 guarded by placing in the outer 1 8-inch space between the 
 two walls a lamp which is electrically connected to, and 
 controlled by, a thermostat. The thermostat consists of a 
 composite strip of rubber and metal, which is held by a 
 clamp at its upper end and curves to right or left under 
 temperature changes, opening or closing, by contact points 
 at the lower end of the thermostat, the electrical circuit 
 which regulates the flame of the lamp. The thermostat is 
 set so as to maintain the space between the two shells at a 
 temperature which shall insure a constant temperature of 
 71 degrees in the inner clock house. This it does with such 
 success that there is less than half a degree of daily 
 variation. 
 
 The two clocks that stand side by side in the clock room 
 serve to keep civil time, that is to say, the local time at the 
 works. The clock to the right carries a twelve-hour dial 
 and is known as the mean-time clock. By means of elec- 
 trical connections it sends time signals throughout the whole 
 works, so that each ■ operative at his bench may time his 
 watch to seconds. The other clock, known as the astronom- 
 ical clock, carries a twenty-four-hour dial, and may be con- 
 nected to the works, if desired. These two clocks serve as a 
 check one upon the other. They were made at the works 
 and they have run in periods of over two months with a 
 variation of less than 0.3 of a second, or 1-259,000 part of a 
 day. The third clock, which stands to the rear of the other 
 two, is the sidereal clock. It is used in connection with the 
 observatory work, and serves to keep sidereal or star time. 
 
 The rate, as observed at the Waltham works, rarely ex- 
 ceeds one-tenth of a second per day. That is to say, the 
 sidereal clock will vary only one second in ten days, or 
 three seconds in a month. The variation, as found, is cor- 
 
THE MODERN CLOCK. 455 
 
 rected by adding or subtracting weights to or from the 
 penduhim, the weights used being small disks, generally of 
 aluminum. 
 
 Summing up, then, we find that the great accuracy ob- 
 tained in this clock room is due to the careful elimination 
 of the various elements that would exercise a disturbing in- 
 fluence. Changes of temperature are reduced to a minimum 
 by insulation of the clock house within an air space, in 
 which the temperature is automatically maintained at an 
 even rate. Changes of humidity are controlled by the spe- 
 cially designed walls, by the lead sheathing of the founda- 
 tion pit, by the preservation of an even temperature, and 
 by placing boxes of hygroscopic material within the inner 
 chamber. Errors due to vibration are eliminated by plac- 
 ing the clocks on massive masonry piers which stand upon 
 a bed of sand as a shock-absorbing medium. 
 
 The astronomical clock is inclosed in a barometric case, 
 fitted with an air pump, by which- the air may be exhausted 
 and the pendulum and other moving parts relieved from 
 barometric disturbances. For it must be understood that 
 variation in barometric pressure means a variation in the 
 density of the air, and that the speed of the pendulum must 
 necessarily be affected by such changes of density. 
 
 Restoring Old Cases. — Very often the watchmaker gets 
 a clock which he knows will be vastly improved by varnish, 
 but not knowing how to take off the old varnish he simply 
 gives it a little sand paper or rubs it oft with oil and lets it 
 go at that. Varnishing such a clock thinly with equal parts 
 of boiled oil and turpentine and allowing it to dry will often 
 restore the transparency of the varnish ; if uneven results 
 are obtained a second coat may be necessary. Many of 
 these old clocks have not been varnished for so many years 
 that the covering of the wood looks like a cheap brown 
 paint. To remove this in the ordinary way means endless 
 labor, and if the case is inlaid with colored patterns of 
 
456 THE MODERN CLOCK. 
 
 veneers, which are partly loosened by the glue drying out, 
 the repairer is afraid to touch it for fear he will only make 
 matters worse in the attempt to better them. 
 
 In the case of an old clock of inlaid marquetry, if the 
 pieces of veneer have become partly loosened, the first thing 
 to do is to make a thin, fresh glue. Work the glue under 
 the veneer and then clamp it down tightly with a piece of 
 oiled paper, or waxed paper, laid between the glue and the 
 board used to clamp with and the whole firmly set down 
 tight with screws or screw clamps. To make waxed paper 
 dissolve paranne wax in benzine and flow or brush on the 
 paper and let dry. After the glue has hardened comes the 
 work of removing the varnish. To do this you will need 
 some varnish remover, which can either be bought at the 
 paint store, or made as follows : 
 
 Varnish Remover. — In doing such work the trick is to 
 make sure that nothing put on the case will injure it, as a 
 clock one hundred years old cannot be replaced. Therefore, 
 if you are suspicious as to the varnish removers you can 
 purchase, and do not want to take chances, you may make 
 one of wood alcohol and benzole, or coal tar naphtha. Be 
 sure you do not get petroleum naphtha, which is common 
 gasoline. The coal tar naphtha is a wood product. The 
 wood alcohol is also a wood product and the varnishes used 
 upon furniture are vegetable gums, so that it will readily 
 be seen that you are putting nothing on the antique with 
 which it was not associated in its natural state. Equal parts 
 of benzole and wood alcohol will dissolve gums instantane- 
 ously, so that if the oil has dried out of the varnish so much 
 that the varnish has become opaque and only the rosins are 
 left, the application of this fluid with a brush will cause in- 
 stant solution, making the gums boil up and form a loose 
 crust upon the surface of the wood, as the liquid evaporates, 
 which it does very rapidly. 
 
THE MODERN CLOCK. 457 
 
 Varnishes containing shellac and some other gums are 
 rather hard to dissolve and where an obstinate varnish is en- 
 countered it may be well to use wax in the varnish remover. 
 This is done by shaving or chopping some parafine wax, 
 dissolving it in the benzole, and when it is clear and trans- 
 parent, add the wood alcohol. Upon the addition of the 
 alcohol the wax immediately curdles so that the fluid be- 
 comes milky. In this condition it is readily brushed upon 
 any surface and when the wax strikes the air it congeals and 
 forms a crust which holds the liquid underneath and enables 
 it to do its work instead of evaporating. 
 
 The wax also serves the purpose of allowing the workman 
 to see just where he Is putting his fluid and of holding it in 
 position upon vertical surfaces or ceilings, round moldings, 
 carved work and other places from which it will quickly 
 run off. Only enough wax should be added to make it 
 spread readily with the brush and after soaking it will be an 
 easy matter to take a painter's putty knife, a case knife, or a 
 scraper and laying it nearly flat on the wood remove all the 
 varnish at one operation, wiping off the knife as fast as it 
 becomes too full. After the bulk of the varnish Is off some 
 of the fluid, without the wax, may be used upon a cloth to 
 go over and smooth up by removing the spots and stripes of 
 varnish left by the knife, or in moldings, etc., where the 
 knife cannot be applied, and we have our bare wood, which, 
 after drying and sand papering, is ready for a fresh coat of 
 XXX coach varnish, which should dry in 24 hours and 
 harden in a week. 
 
 A very little work and practice in this will enable the 
 workman to rapidly and cheaply clean up and repair an- 
 tiques in such a way that it will add greatly to his repu- 
 tation. 
 
 To restore the gloss of polished wood it Is not always the 
 best plan to employ true furniture polish. The majority of 
 the so-called polishes for wood are based on a mixture of 
 boiled linseed oil and shellac varnish, made by dissolving 
 
45^ THE MODERN CLOCK. 
 
 shellac in alcohol in the proportion of four ounces of shellac 
 to a pint of alcohol. A little of the dissolved shellac is 
 poured on to a canton-flannel rag, a few drops of the boiled 
 linseed oil are placed on the cloth, and the wood to be pol- 
 ished is rubbed vigorously. About half an ounce of cam- 
 phor gum dissolved with the shellac in the alcohol will 
 greatly facilitate the operation of polishing. 
 
 A soft woolen rag, moistened with olive oil and vigorously 
 rubbed on dull varnished surfaces, like old clock cases, will 
 brighten the surface wonderfully. Some workmen add a 
 few drops of a strong solution of camphor gum in alcohol 
 to the olive oil. 
 
 The polishing of cases is accompHshed by applying sev- 
 eral coats of the best coach painters' rubbing varnish, when, 
 after perfect drying, the surface is rubbed with a felt or a 
 canton-flannel rag, folded flat, using water and the finest 
 pulverized pumic stone. This operation smooths the sur- 
 faces. The final polishing of such work is done by rubbing 
 with rotten stone and olive oil with the smooth side of 
 canton flannel. To remove the last traces of smear caused 
 by the oil, an old, soft linen cloth and rye flour is used. Of 
 course, fine work like we see on new cases of fine quality is 
 not likely to be produced by one who is unaccustomed to it; 
 a man must serve a good, long apprenticeship in the varnish 
 finishing business before he is competent for it; and even 
 then some polishers fail to obtain the fine results achieved by 
 others. The great danger is that the rubber will cut 
 through the varnish and expose the bare wood on edges, cor- 
 ners and even in spots on plane surfaces, before he has re- 
 moved the lumps and streaks of varnish on adjacent portions 
 of the work. Whenever the varnish is flat and smooth in 
 any spot, you must stop rubbing there. 
 
 Black wood clocks which have become smoked and dull 
 should have the cases rubbed with boiled oil and turpentine 
 on a piece of soft woolen rag ; afterwards polish off with 
 a dry rag. If the gloss has been destroyed it will have to be 
 
THE MODERN CLOCK. 459 
 
 varnished. Flow the varnish well on and use i^-inch 
 brush and be careful to get the varnish on even and so as not 
 to trickle. This is easy if you are careful to keep the var- 
 nish thin and do not go over the varnish a second time 
 after spreading it on. Thin with turpentine and put very 
 little on the case ; it is already smooth and a mere film will 
 give the gloss. For white filling on the engraving on black 
 cases use Chinese white or get a good white enamel at a 
 paint store. 
 
 Gilding on wood cases is done by mixing a little yellow 
 dry color with thin glue and painting the cases with the 
 mixture ; the color lets you see what you are doing. When 
 the glue has dried until it is "tacky," lay gold leaf on the 
 painted portions and smooth down with cotton. If you have 
 any holes do not attempt to patch them. It is easier and 
 quicker to put on another sheet of gold leaf over the first 
 one. After the gold is dry, it may be burnished with a 
 bloodstone or smooth steel burnisher, or it may be left dead. 
 Finish with colorless lacquer, very thin and smooth. 
 
 Imitation gold leaf, known to the trade as Dutch Mietal, 
 may be substituted for the gold leaf, if the latter is thought 
 to be too expensive, but in such cases be sure to have the 
 metal well covered with the lacquer, as unless this is done 
 it will blacken in two or three years — sometimes in two or 
 three months. 
 
 Bronze powder may be applied to the glue size with a tuft 
 of cotton and well rubbed in until flat and smooth ; then 
 lacquer and dry. Never put on bronze paint, for the follow- 
 ing reason : If we examine the bronze under a microscope 
 we shall find that it is composed of flat scales like fish scales; 
 if mixed as a paint they will be found lying at all angles in 
 the painted work — many standing on edge. Such scales 
 reflect the light away from the eye and make the work look 
 dull and rough. If we rub these dry scales in gently on the 
 sticky size, we will lay them all down flat and smooth,- so 
 that the work will glisten all over with an even color. Al- 
 
460 THE MODERN CLOCK. 
 
 ways lacquer bronzed work — yellow lacquer being the best 
 — and put on plenty of lacquer. 
 
 Metal ornaments, when discolored, should be removed 
 from the case, dipped in boiling lye to remove the lacquer, 
 scratch brushed, dipped in ammonia to brighten, rinsed in 
 hot water and dried in sawdust. They may then be lac- 
 quered with a gold lacquer, or plated in one of the gold 
 plating solutions sold by dealers for plating without a bat- 
 tery and then lacquered, if bright. If they are of oxidized 
 finish cleaning and lacquering is generally all that is neces- 
 sary. 
 
 Oxidized metal cases, if badly discolored, should be sent 
 to an electroplater to be refinished, as the production of 
 smooth and even finishes on such cases, requires more skill 
 than the clock repairer possesses, and he therefore could 
 not do a good job, even if he had the necessary materials 
 and formulae. 
 
 Marble cases are made of slabs, cemented together. 
 Many workmen use plaster of paris by merely mixing it 
 with water, though we rather think it better to use glue in 
 the mixing, as plaster so mixed will not set as quickly as 
 that mixed with water. After the case is cemented with the 
 plaster, the workman can go over the joint with a brush and 
 water colors, and with a little care should be able to turn 
 out a job in which the joint will not be noticeable. Another 
 cement much used for marble is composed of the white of 
 an egg mixed with freshly slaked lime, but it has the dis- 
 advantage of setting very quickly. 
 
 Marble case makers use a cement composed of tallow, 
 brick dust, and resin melted together, and it sets as hard 
 as stone at ordinary temperatures. 
 
 It often happens that the marble case of a mantel clock 
 is injured by some accident and its corners are generally 
 the first to suffer. If the break is not so great as to war- 
 rant a new case or a new part the repairer may make the 
 
THE MODERN CLOCK. 461 
 
 case a little smaller or file until the edges are reproduced, 
 after which the polish is restored. Proceed as follows : 
 
 Take off from the damaged part as much as is necessary 
 by means of a file, taking care however, not to alter the 
 original shape of the case. Now grind off the piece worked 
 with the file with a suitable piece of pumice stone and 
 water and continue the grinding next with a water stone 
 until all the scratches have disappeared, paying special at- 
 tention to the corners and contours. After this has been 
 done take a hard ball of linen, moisten it, and strew over 
 it either tripoli or fine emery and proceed to polish the 
 case with this. Finish the polishing with another linen 
 ball, using on it still finer emery and rouge. Now dry the 
 case and finish the polishing with a mixture of beeswax 
 and oil of turpentine. This method may be employed for 
 all kinds of marble, or onyx and alabaster cases. 
 
 In cases where the fractures are very deep, so that the 
 object cannot be made much smaller without ruining the 
 shape, the damaged parts may be filled with a cement, pre- 
 pared from finely powdered marble dust and a little isin- 
 glass and water, or fish glue wall answer very well. Stir 
 this into a thick paste, which fill into the deep places and 
 permit to dry ; after drying, correct the shape and polish 
 as described. 
 
 If the pieces which have been broken off are at hand 
 they may be cemented in place again. Wet the pieces with 
 a solution of water and silicate of potash, insert them in 
 place and let them dry for forty-eight hours. If the case 
 is made of white marble use the white of an egg and a 
 little Vienna lime, or common lime will answer. 
 
 To Polish Marble Clock Cases. — It frequently be- 
 comes the duty of the repairer to restore and polish marble 
 clock cases, and we would recommend him to make a thin 
 paste of the best beeswax and spirits of turpentine, clean 
 the case well from dust, etc., then slightly cover it with 
 
462 THE MODERN CLOCK. 
 
 the paste, and with a handful of clean cotton, rub it well, 
 using abundant friction, finish off with a clean old linen 
 rag, which will produce a brilliant black polish. For light 
 colored marble cases, mix quicklime with strong soda water, 
 and cover the marble with a thick coating. Glean off after 
 twenty-four hours, and polish well with fine putty powder. 
 To Remove Oil Spots From Marble. — Oil spots, if not 
 too old, are easily removed from marble by repeatedly cov- 
 ering them with a paste of calcined magnesia and benzine, 
 and brushing off the magnesia after the dissipation of the 
 oil; this may have to be repeated several times. Another 
 recipe reads as follows : Slaked lime is mixed with a strong 
 soap solution, to the consistency of cream; this is placed 
 upon the oil spot, -and repeated until it has disappeared. In 
 place of this mixture, another one may be used, consisting 
 of an ox gall, 125 grains of soapmaker's waste lye and 62^ 
 grams of turpentine, with pipe clay, to the consistency of 
 dough. 
 
 Cutting Clock Glasses. — You will sometimes want a 
 new glass for a clock. I get a lot of old 5x7 negatives and 
 scald the film off in plain hot water, rinse well and dry. 
 Now I lay my clock bezel on a piece of paper and trace 
 around with a pencil, inside measure. Now remove the 
 bezel and trace another circle around the outside of this 
 circle about one-eighth inch. Now, lay the paper on a 
 good, solid, smooth surface, glass on top, and with a com- 
 mon wheel glass-cutter follow around the outside line, free 
 handed, understand. The paper with marked circle on is 
 under the glass, and you can see right through the glass 
 where to follow with the cutter. Now cut the margins of 
 glass so as to roughly break out to one-half inch of your 
 circle cut, running the cuts out on the side, then carefully 
 break out. 
 
CHAPTER XXIV. 
 
 SOME HINTS ON MAKING A REGULATOR. 
 
 Of all the instruments used by a watchmaker in the 
 prosecution of his business, there is probably none more 
 iniportant than his regulator. Its purpose is to divide time 
 into seconds, and it is the standard by which the practical 
 results of his labors are tested ; the guide which all the 
 other time-keepers in his possession are made to follow and 
 the arbitrator which settles all disputes regarding the per- 
 formance of his watches. 
 
 No regulator has yet been constructed that contains with- 
 in itself every element for producing absolutely accurate 
 time-keeping. At intervals they must all be corrected from 
 some external source, such as comparison with another 
 time-keeper, the error of which is known, or by the motion 
 of the heavenly bodies, when instruments for that purpose 
 are available. Before beginning to make a regulator, the 
 prudent watchmaker will first reflect on the various plans of 
 constructing all the various details of an accurate time- 
 keeper, and select the plan which, in his opinion, or in the 
 opinion of those whom he may consult on the subject, will 
 best accomplish the object he has in view. 
 
 In former 3-ears a regulator case was made with the sole 
 object of accommodating the requirements of the regulator, 
 and every detail in the construction of the case was made 
 subservient to the necessities of the clock. The plain, well- 
 made cases of former years are now almost discarded for 
 those of more pretentious design. If the general change in 
 the public taste demands so much display, there can be no 
 objection. It is perfectly harmless to the clock, if the de- 
 
 463 
 
464 THE MODERN CLOCK. 
 
 signers and makers of the cases would only remember that 
 narrow waists or narrow necks on a case, although part of 
 an elegant design, do not afford the necessary room for the 
 weight and freedom of the pendulum; that the doors and 
 other openings in the case must be constructed with a view 
 to exclude dust ; and that the back should be made of thick, 
 well-seasoned hardwood, such as oak or maple, so as to 
 afford the means of obtaining as firm a support for the pen- 
 dulum as possible. 
 
 When a regulator case is known to have been made by an 
 inexperienced person, which sometimes happens, or when 
 we already have a case, it is always the safest course for 
 those who make the clock to examine the case personally 
 and see the exact accommodation there is for the clock. 
 Sometimes, when we know beforehand, we can, without 
 violating any principle, vary the construction a little, so as 
 to make the weight clear the woodwork of the inside of the 
 case, and in other respects complete the regulator in a more 
 workmanlike manner by making the necessary alterations 
 in the clock at the beginning of its construction, instead of 
 after it has been once finished agreeably to some stereotyped 
 arrangement. 
 
 The arrangement of the mechanism of an ordinary regu- 
 lator is a simple operation compared with some other 
 horological instruments of a more complex character. We 
 are not limited in room to the same extent as in a watch, 
 and the parts being few in number a regulator is m.ore 
 easily planned than timekeepers having striking or auto- 
 matic mechanism for other purposes combined with them; 
 yet it often happens that the inexperienced make serious 
 blunders in planning a regulator, and, as the clock ap- 
 proaches completion, many errors make themselves visible, 
 which might have been avoided by the exercise of a little 
 more forethought. It may be that, when the dial is being 
 engraved, the circles do not come in the right position, or 
 the weight comes too close to the pendulum, or the case. 
 
THE MODERN CLOCK. 46s 
 
 or the cord comes against a pillar, or other faults of greater 
 or less importance appear, all of which might have been ob- 
 viated by taking a more comprehensive view of the subject 
 before beginning to make the clock. The best way to do 
 this is to draw a plan and side and front elevations to a 
 scale. 
 
 Fig. 152 
 
 The position which the barrel and great wheel should 
 occupy is worthy of serious consideration. In most of the 
 cheap regulators, as well as in a few of a more expensive 
 order, the barrel is placed in a direct line below the center 
 wheel, as is shown in Fig. 152. This arrangement admits 
 of a very compact movement, and it also allows the weight 
 to hang exactly in the center of the case, which some think 
 
466 THE MODERN CLOCK. 
 
 looks better than when it hangs at the side, especially when 
 there is a glass door in the body of the case. But while a 
 weight hanging in the center of a case may be more pleas- 
 ing to the eye than when it hangs at the side, this is an in- 
 stance where looks can, with great propriety, be sacrificed 
 for utility, because when the weight hangs in the center it 
 comes too close to the pendulum, and is very liable to dis- 
 turb its motion. In proof of this statement, let any reader 
 who has a regulator with a light pendulum and a com- 
 paratively large weight hanging in front of it, closely watch 
 the length of the arc the pendulum vibrates when the weight 
 is newly wound up and when it is down opposite the pen- 
 dulum ball, and he w411 observe that the length of vibration 
 of the pendulum varies from five to fifteen minutes of arc, 
 according to the position in which the weight is placed ; 
 that the pendulum will vibrate larger arcs when the weight 
 is above or below the ball than when it is opposite it ; and 
 if the clock has a tendency to stop from any cause, that it 
 will generally do so more readily when the weight is op- 
 posite the pendulum ball than when it is in any other posi- 
 tion. For this reason I would dispense with the symetrical 
 looks of the weight hanging in the center of the case, wdiich, 
 after all, is only a matter of taste, and construct the move- 
 ment so that the weight will hang at the side, and as, far 
 away from the pendulum as possible. 
 
 Fig. 153 is intended to represent the effect which plac- 
 ing the barrel at either side has on throwing the w^eight 
 away from the pendulum. A is the center wheel ; B and C 
 are the great wheels and barrels with weights hanging from 
 them; D is the pendulum. It will be noticed by the dia- 
 gram that the weight at the left of the pendulum is exactly 
 the diameter of the barrel farther away from the pendulum 
 than the weight on the right. On close inspection it will 
 also be observed that on the barrel C the force of the weight 
 is applied between the axis of the barrel and the teeth of 
 the wheel, while on the barrel B the axis of the barrel lies 
 
THE MODERN CLOCK. 
 
 467 
 
 between the point where the force is appHed and the point 
 where the teeth act on the pinion ; consequently a httle more 
 of the effective force of the weight is consumed by the 
 extra amount of pressure and friction on the pivots of the 
 barrel B than there is in C. 
 
 Notwithstanding this disadvantage, I would for a regu- 
 lator recommend the barrel to be placed at the left side of 
 
 ,. Fig. 153 
 
 the center wheel, because the weight may thereby be led a 
 sufficient distance from the pendulum in a simple manner. 
 If we place the barrel at the right, and thereby secure the 
 greatest effective force of the weight, and then lead the 
 weight to the side by a pulley, we will lose a great deal 
 more by the friction of the pulley than we gain by the 
 proper application of the weight. 
 
 In a regulator with a Graham escapement but little force 
 is required to keep it going, and there is usually accommo- 
 
468 THE MODERN CLOCK. 
 
 dation for an abundance of power ; therefore we cannot use 
 a little of this superabundant available force to better ad- 
 vantage than by placing the barrel at the left side of the 
 clock, and thereby throw the weight a sufficient distance 
 from the pendulum in the simplest manner. 
 
 The escapement we assume to be the old dead beat, as for 
 tim.e-keeping it is equal to a gravity escapement while pos- 
 sessing advantages undesirable to sacrifice for a doubtful 
 improvement. The advantages it possesses over any form 
 of gravity escapement are : it has fewer pieces and not so 
 many wheels ; it takes very much less power to drive ; is not 
 liable to fail in action while winding, if the maintaining 
 power should be rather weak; while for counting, seconds 
 and estimating fractions, its clear, definite, and equable beat 
 has great superiority over the complication of noises made 
 by a gravity escapement. 
 
 Full directions for making this and other escapements 
 have already been given, but in a regulator there are some 
 considerations which will not be encountered in connection 
 with the escapements of ordinary clocks, where fine time- 
 keeping is not expected. We have previously stated that 
 the center of suspension of the pendulum should be exactly 
 in line with the axis of the escapement and we will now 
 endeavor to state plainly how important this Is in a fine 
 clock and the reasons for it. Mr. Charles Frodsham, the 
 noted English chronomiCter maker, has conducted a series of 
 careful experiments and the results were communicated in 
 a report to the British Horological Society, as follov/s : 
 
 When we talk of detached escapements, or any escape- 
 ment applied to a pendulum, it is necessary to bear in mind 
 that there is always one-third at the least of the pendulum's 
 vibration during which the arc of escapement is intimately 
 mixed up with the vibration, either in locking, unlocking, 
 or in giving impulse; therefore, whatever inherent faults 
 any escapement may possess are constantly mixed up in the 
 result; the words ''detached escapement" can hardly be ap- 
 
THE IVODERN CLOCK 469 
 
 plied when the entire arc of vibration is only two degrees ; 
 or, in other words, what part of the vibration is left with- 
 out the influence of the escapement? — at most one degree. 
 In chronometers the arc of vibration is from ten to fifteen 
 times greater than the arc of escapement. 
 
 The dead-beat escapement has been accused of interfer- 
 ing with the natural isochronism of the pendulum by its 
 extreme friction on the circular rests, crutch, and difficulty 
 of unlocking, etc., all of which we shall show is only so 
 when improperly made. 
 
 When the dead-beat escapement has been mathematically 
 constructed, and is strictly correct in all its bearings, its vi- 
 brations are found to be isochronous for arcs of different 
 extent from 0.75 of a degree to 2.50 degrees ; injurious 
 friction does not then exist; the run up on the locking has 
 no influence, nor is there any friction at the crutch ; oil is 
 not absolutely necessary, except at the pivots; and there 
 is no unlocking resistance nor any inclination to repel or 
 attract the wheel at its lockings. 
 
 The general mode of making this escapement is very de- 
 fective and indefinite, and entirely destroys the naturally 
 isochronous vibration of the pendulum. 
 
 The following is the usual rate of the same pendulum's 
 performance in the different arcs of vibration with an 
 escapement as generally constructed after empirical rules : 
 
 Arc of vibration 3° rate per diem 9.0 seconds. 
 
 Arc of vibration 2^° rate per diem 6.0 seconds. 
 
 Arc of vibration 2° rate per diem 3.5 seconds. 
 
 Arc of vibration ij4° rate per diem 1.5 seconds. 
 
 Arc of vibration 1° rate per diem 0.0 seconds. 
 
 Thus for a change of vibration of 1°, we have a daily er- 
 ror of 3.5. No change of suspending spring will alter in- 
 herent mechanical errors destructive of the laws of motion. 
 With clocks made in the usual manner, whether you apply 
 a long or short spring, strong or weak, broad or narrow, 
 
4.70 THE MODERN CLOCK. 
 
 you will not remove one fraction of the error ; so the sooner 
 the fallacy of relying upon .the suspending spring to cure 
 mechanical errors is exploded the better. 
 
 That the suspending spring plays a most important part 
 must be admitted, since, when suspended by a spring, a 
 pendulum is kept in motion by a few grains only, whereas, 
 if supported on ordinary pivots, 200 lbs. weight would not 
 drive it 2' beyond its arc of escapement, so great would be 
 the friction at the point of suspension. 
 
 The conditions on which alone the vibrations of the pen- 
 dulum will be isochronous are the following: 
 
 1. That the pendulum be at time with and without the 
 clock, in which state it is isochronous "suspended by a 
 spring." 
 
 2. That the crutch and pallets shall each travel at the 
 same precise angular velocity as the pendulum, which can 
 only happen when the arc ^ach is to describe is in direct 
 proportion to its distance from the center of motion, that 
 is, from the pallet axis. 
 
 3. That the angular force communicated by the crutch 
 to the pendulum shall be equal on both sides of the quiescent 
 point; or, in other. words, that the lead of each pallet shall 
 be of the same precise amount. 
 
 4. That any number of degrees marked by the crutch or 
 pallets shall correspond with the same number of degrees 
 shown by the lead of the pendulum, as marked by the index 
 on the degree plate. 
 
 5. That the various vibrations of the pendulum be 
 driven by a motive weight in strict accordance with the 
 theoretical law ; that is, if a 5-lb. weight cause the pendulum 
 to double its arc of escapement of 1°, and consequently 
 drive it 2°, all the intermediate arcs of vibration shall in 
 practice accord with the theory of increasing or diminishing 
 their arcs in the ratio of the square roots of the motive 
 weight. 
 
THE MODERN CLOCK. 47I 
 
 To accomplish the foregoing conditions, there is but one 
 fixed point or Hne of distance between the axis of the 
 escape wheel and that of the pallet, and that depends upon 
 the number of teeth embraced by the pallets and only one 
 point in which the pallet axis can be placed from which the 
 several lines of the escapement can be correctly traced and 
 properly constructed with equal angles, and equal rectangu- 
 lar lockings on both sides, so that each part travels with 
 the same degree of angular velocity, which are the three 
 essential points of the escapement. 
 
 Much difference of opinion has been expressed upon the 
 construction of the pallets, as to whether the lockings or 
 circular rests should be at equal distances from the pallet 
 axis, with arms and impulse planes of unequal length, or 
 at unequal distances from the pallet axis, with arms and im- 
 pulse planes of equal length. In the latter case the locking 
 on one side is three degrees above, and on the other three 
 degrees below the rectangle, whereas in the former the tooth 
 on both sides reposes at right angles to the line of pressure; 
 but the length of the impulse planes is unequal. When an 
 escapement is correctly made upon either plan, the results 
 are very similar. 
 
 It is possible to obtain equal angles by a false center of 
 motion or pallet axis ; but then the arcs of repose will not 
 be equal. This, however, is not of so much consequence as 
 that of having destroyed the conditions Nos. 2, 3, 4; for 
 even at correct centers, if the angles are not drawn off cor- 
 rectly by the protractor, and precisely equal to each other, 
 the isochronous vibrations of the pendulum will be destroy- 
 ed, and unequal arcs will no longer be performed in equal 
 times ; the quiescent point is not the center of the vibration, 
 except when the driving forces are equal on both sides of 
 the natural quiescent point of the pendulum at rest. 
 
 Now this is the very pith of the subject, and which few- 
 would be inclined to look for with any hope of finding in 
 
472 THE MODERN CLOCK. 
 
 it the solution of this important question, the isochronism 
 of the pendulum. 
 
 - One would naturally suppose that unequal arcs on the 
 two sides of the vertical lines would not seriously affect the 
 rate of the clock, but would be equal and contrary, and con- 
 sequently a balance of errors, and so they probably are for 
 the same fixed vibration, but not for any other; because 
 dififerent angles are driven with different velocities, the 
 short angle has a quicker rate of motion than the long. 
 Five pounds motive weight will multiply three times the 
 pendulum's vibration over an arc of escapement of 0.75°; 
 but the same pendulum, with an arc of escapement of 1°, 
 would require 11.20 lbs. to treble its vibration; the times of 
 the vibration vary in the same ratio as the sum of the 
 squares of the differences of the angles of each pallet, com- 
 pared with the spaces passed over. 
 
 From this it will be seen that the exact bending point of 
 the pendulum spring should be opposite the axis of the 
 fork arbor when regulating the clock and this may have 
 to be determined by trial, raising or lowering the plates by 
 screws in the arms of the suspending brackets until the 
 proper position is found, when the movement may be 
 clamped firmly in position by the binding screws, see Fig. 
 
 158. 
 
 On common clocks the crutch is simply riveted on its 
 collet and bent as required to set the clock in beat, but for 
 a first-class clock a more refined arrangement is usually 
 adopted. There are other plans, but perhaps none so thor- 
 oughly sound and convenient as the following. The crutch 
 itself is made of a piece of flat steel cut away so as to leave 
 a round boss at the bottom for the fork, and a round boss 
 at the top to fit on a collet on the pallet arbor, a part pro- 
 jecting above to be embraced between a pair of opposing 
 screws. On the collet is fixed a thin brass plate with two 
 lugs projecting backwards from the frame, these lugs be- 
 ing drilled and tapped to receive the opposing screws in a 
 
THE MODERN CLOCK. 473 
 
 line. The boss of the crutch Hes flat against this plate, and 
 is held up to it by, a removable collet. The collet may be 
 pinned across or fitted keyhole fashion, in either case so as 
 to hold the crutch firmly, allowing it to move with a little 
 stiffness under the influence of the screws. With this ar- 
 rangement the adjustment to beat may be made with the 
 utmost delicacy by slacking one screw and advancing the 
 other, taking care that in the end they are well set home so 
 as to make the crutch practically all one piece with the 
 arbor. Milled heads are most convenient for these screws, 
 and being placed at the top they are easily got at. The 
 crutch should always be fitted with a fork to embrace the 
 pendulum rod, as this ensures the impulse being given di- 
 rectly through the center, and with the same object the act- 
 ing sides of the fork should be truly square to the frame. 
 A slot in the pendulum rod with a pin acting in it is never 
 so sure of being correct, as, although the surfaces may be 
 rounded, it is very unlikely that the points*of contact will 
 be truly in the plane of the axis of the rod. The slightest 
 error in this respect will tend to cause wobbling of the bob, 
 although, to avoid this, great attention must also be given 
 to the suspension spring, the pin on which it hangs, and the 
 pin and the hole at the top of the pendulum rod. All these 
 points must be in a true line, and the spring symmetrical on 
 both sides of the line in order that the impulse may be given 
 exactly opposite the center of the mass, otherwise wobbling 
 must occur, although perhaps of an amount so small as to 
 be difficult of detection, and this is not a matter" of small im- 
 portance, as it has an efifect on the rate which could be 
 mathematically demonstrated. 
 
 The frames of many regulators are made too large and 
 heavy. In some cases there may be good reasons for mak- 
 ing them large and heavy, but in most instances, and espe- 
 cially when the pendulum is not suspended from the move- 
 ment, it would be much better to make the frames lighter 
 than we frequently find them. Very large frames present 
 
474 THE MODERN CLOCK. 
 
 a massive appearance, and convey an idea of strength alto- 
 gether out of proportion to the work a regulator is required 
 to perform. They are more difficult and more expensive to 
 make than lighter ones, and after they are made they are 
 more troublesome to handle, and the pivots of the pinions 
 are in greater danger of being broken when the clock is be- 
 ing put together than when they are moderately light. 
 
 In a clock such as we have under consideration, where 
 the frame is not to be used as a support for the pendulum, 
 but simply to contain the various parts which constitute the 
 movement, the thickness of the frames may with propriety 
 be determined on the basis of the diameter of the majority 
 of the pivots which work into the holes of the frames. The 
 length of the bearing surface of a pivot will, according to 
 circumstances, vary from one to two and a half times the 
 diameter of the pivot. The majority of the pivots of our 
 regulator will not be more than .05 or .06 of an inch in 
 diameter; consequently a frame 0.15 of an inch thick will 
 allow a sufficient length of bearing for the greater portion 
 of the pivots, and will also allow for countersinks to be 
 made for the purpose of holding the oil. If thin plates are 
 used one or two of the larger pivots should be run in bushes 
 placed in the frame, as described in Fig. 155. 
 
 The length and breadth of the frame, and also its shape, 
 should be determined solely on the basis of utility. There 
 can be no better shape for the purpose of a regulator than 
 a plain oblong, without any attempt whatever at ornament. 
 For our regulator a frame nine inches long and seven inches 
 broad will allow ample accommodation for everything, as 
 may be seen on referring to Fig. 157. 
 
 The plates are made of various alloys : cast-brass, nickel- 
 silver, and hard-rolled sheet-brass. It is difficult to make 
 plates of cast-brass which would be even, free from specks, 
 etc., but cast plates may very well be made of ornamental 
 patterns and bushings of brass rod inserted, or they may 
 be jeweled as shown in Figs. 154, 155, 156. Nickel, or 
 
THE MODERN CLOCK, 
 
 475 
 
 German silver, makes a fine plate, but it is difficult to drill 
 the small holes through plates of four-tenths of an inch in 
 thickness, on account of the peculiar toughness of the metal, 
 so that bushings are necessary. The best material where 
 the holes are to be In the plates Is fine, hard-rolled sheet 
 brass; it should have about 4 oz. of lead to the 100 lbs., 
 which will make it "chip free," as clockmakers term it, 
 rendering it easy to drill ; the metal is so fine and condensed 
 to that extent by rolling, that the holes can be made with 
 the greatest degree of perfection. The many improvements 
 in tools and machinery have effected great changes and im- 
 provements in clock-making. It once was quite a difficult 
 task to drill the small holes in the plates with the ordinary 
 drills and lathes ; now we lay the plates "after they are sold- 
 
 I rniLiMK I 
 
 ^i^^ i A 
 
 Fig. 154 
 
 ered together at the edges (which is preferable to pinning)', 
 on the table of an upright drill, and with one of the modern 
 twist-drills the task Is rendered a very easy one. After the 
 pivot-holes are drilled-, we run through from each side a 
 round broach, finished lengthwise and hardened, which acts 
 as a fine reamer, straightening and polishing the holes ex-' 
 quisitely. A little oil should be used on the reamer to prevent 
 sticking. The method of fitting up the pivot-holes invented 
 by LeRoy, a French clockmaker of some note, is shown in 
 Fig. 154. It is a sectional view of the plate at the pivot- 
 hole. It will be observed that. Instead of countersinking 
 for the oil, the reverse is the case. A is a hardened steel 
 plate counterbored into the clock plate B, and held In its 
 place by the screws. There should be a small space between 
 the steel plate and the crown of the arch for the oil. After 
 the clock has been put together it Is laid down on its face 
 
476 
 
 THE MODERN CLOCK. 
 
 or side, a drop of oil is put to the pivot end, and the steel 
 plate immediately put on; and the oil will at once assume 
 the- shape of the shaded spot in the drawing, being held in 
 the position at the center of the pivot by capillary attraction, 
 until it is exhausted by the pivots; the steel plates also 
 govern the end play of the pinions. The pivot ends being 
 allowed to touch the plates occasionally, the shoulders of the 
 pinions are turned away into a curve, and, of course, do not 
 bear against the plate, as in most clocks. 
 
 Fig. 155 
 
 Glass plates may be used instead of steel, or rose cut thin 
 garnets, or sapphires, with the flat sides smoothly polished, 
 may be bought of material dealers and set in bezels like a 
 cap jewel. They are very hard and smooth for the pivot 
 
 Fig. 156 
 
 ends, and the state of the oil at the pivots can be seen at any 
 time. Clocks fitted up in this manner have been running 
 many years without oiling. 
 
 When fitted up in this way the plates may be thicker. 
 We have made the clock plates about four-tenths of an inch 
 in thickness, which allows of counterboring, and admits of 
 long bearings for the barrel arbor, which are so liable to be 
 worn down in the holes by the weights ; and the pivots of 
 the pinions, by being a little longer, do not materially in- 
 crease the friction. 
 
THE MODERN CLOCK. 477 
 
 In first-class clocks, when all the materials are as hard 
 as possible, the wheels and pinions high numbered, the 
 teeth, pinions, pivots, and holes smooth, true, and well pol- 
 ished, the amount of wear Is very slight, especially if the 
 driving weight has no useless excess. Yet there are ad- 
 vantages in having some parts jeweled, such as the pallets 
 and the four escapement holes. The cost of sufli jeweling 
 is not an objection, while the diminished friction of the 
 smooth, hard surfaces is worth the extra outlay. The holes 
 can be set in the bushes described in Fig. 156, the end 
 stones being cheap semi-precious stones, either rose cut or 
 round. 
 
 For jeweling the pallets, dovetailed slots may be made so 
 that the stones will be of a wedge shape; there is no need 
 for cutting the slots right through as in lever watch pallets. 
 The stones will be held more firmly if shaped as wedges 
 lying on a bed of the steel and exposing only the circular 
 resting- curve and the driving face. The slots can be filed 
 out and the stones ground on a copper lap to fit, fixed with 
 shellac and pressed firmly home while warm. The grind- 
 ing and polishin^^ of the acting suriaces are done exactly as 
 described for hard steel, only using diamond powder instead 
 of emery. The best stones are pale milky sapphires, such 
 as are useless as gems, this kind of stone being the hardest. 
 
 The holes may be much shorter when jeweled, as the 
 amount of bearing surface required with stones is less 
 than with brass; this results in less adhesion through the 
 oil, and less variation of force through its changes of con- 
 sistency. The 'scape wheel may also be thinner w^th similar 
 results, and less weight to be moved besides. So the advan- 
 tages of jeweling are worth consideration. 
 
 It is important to finish the wheels and pinions before 
 drilling any holes in the plates and then to definitely locate 
 the holes after trial in the depthing tool. 
 
 For the clockmaker's use the next in value to the wheel- 
 cutting engine is a strong and rigid depthing tool, for it is 
 
478 THE MODERN CLOCK. 
 
 by means of this instrument that the proper center distances 
 of wheels and pinions can be ascertained, and all errors in 
 sizes of wheels and pinions, and shapes of teeth, are at once 
 detected before the holes are drilled in the plates. In fact, 
 this tool becomes for the moment the clock itself ; and if 
 the workman will consider that as the wheels and pinions 
 perform fh the tool for the little time he is testing them, so 
 they will continue to run during the life of the clock, he 
 will not be too hasty in allowing wheels to go as correct 
 when a hundredth of an inch larger or smaller, and another 
 test, would, perhaps, make the pitching perfect. 
 
 There are various kinds of depthing tools in use, but 
 many of them are objectionable for the reason that the cen- 
 ters are so long that the marking points on their outer ends, 
 are too far from the point where the pitching or depthing 
 is being tested, and the slightest error in the parallelism of 
 these centers is, of course, multipHed by the distance, so 
 that it m.ay be a serious difference. Having experienced 
 some trouble from this cause, we made an instrument with 
 very short centers, on the principle that the marking points, 
 or centers, should be as near the testing place as possible. 
 We succeeded in making one with a difference of only 
 three-fourths of an inch, which was so exact that we had 
 no further trouble. It was made on the Sector plan, but 
 upright, so that the work under inspection, whether wheels 
 and pinions, or escapements, could be observed closely, and 
 with a glass, if necessary. 
 
 It is very important that the posts or pillars and side- 
 plates of clocks should be m.ade and put together in the 
 most thorough manner ; the posts should be turned exact to 
 length and have large shoulders, turned true, so that the 
 plates, when put together without screws should fit accur- 
 ately, for if they do not, when the screws are driven, some 
 of the pivots will be cramped. We prefer iron for the 
 posts, it being stiffer, and better retaining the screw threads 
 in the ends, which in brass are liable to strip unless long 
 
I bc 
 
480 
 
 THE MODERN CLOCK. 
 
 and deep holes are tapped. Steel pillars should be blued 
 after being finely finished, thus presenting a pleasing con- 
 trast. The plate screws should also be of steel, with large 
 flat heads, turned up true, and having a washer next to the 
 plate. Brass pillars are favored by many and are easier 
 turned in a small lathe, but they should be much larger 
 than the steel ones. 
 
 When the pillars are made of brass round rod of proper 
 diameter is the best stock. If this cannot be procured, a 
 pattern is turned from wood, and a little larger in every 
 respect than the pillar is desired to be. If there is to be 
 any ornament put on the pillar, it is never made on the pat- 
 tern, because it makes it more difficult to cast, and besides, 
 the ornamentation would all be spoiled in the hammering. 
 The pattern must be turned smooth, and the finer it is the 
 better w^ill be the casting. After the casting is received the 
 
 ":> 
 
 Fig. 159 
 
 first thing to be done is to hammer the brass, and then cen- 
 ter the holes, because it will be seen from Fig. 159 that 
 there are holes for screws at each end of the pillar. Holes 
 of about .20 of an inch are then bored in the ends of the 
 pillars, and should be deep, because deep holes do no harm 
 and greatly facilitate the tapping for the screws. After the 
 holes are tapped, run In a bottoming tap and then counter- 
 sink them a little, to prevent the pillar from going out of 
 truth in the turning. It will depend a great deal on the 
 conveniences which belong to the lathe the pillars are turn- 
 ed in as to how they will be held in the lathe and turned. 
 If the holes in the ends of the pillars have been bored and 
 tapped true, and if the lathe has no kind of a chuck or 
 face plate with dogs, suitable for holding rods, the best 
 
THE MODERN CLOCK. 481 
 
 way IS to catch a piece of stout steel wire in the chuck and 
 turn it true, cut a true screw on it, and on this screw one 
 end of the pillar, and run the other end in a male center. 
 However, if the screws are not all perfectly true, and the 
 centers of the lathe not perfectly in line, this plan will not 
 work well, and it will be necessary to catch a carrier on to 
 the pillar and turn it between two male centers. 
 
 The dial feet are precisely the same as the pillars, only 
 smaller. These dial feet are intended to be fastened in the 
 frame by a screw, the same as the pillars ; but it will be ob- 
 served that the screw which is intended to hold the dial on 
 the pillar is smaller. The dial feet will be turned in precise- 
 ly the same manner as the pillars. For finishing the plain 
 surfaces of the pillars and dial feet, an old 6 or 7-inch 
 smooth file makes a good tool The end of the file is ground 
 flat, square or slightly rounded, and perfectly smooth. The 
 smoother the cutting surface the smoother the work done 
 by it will be. It is difficult to convey the idea to the inex- 
 perienced how to use this tool successfully. In the first 
 place, a good lathe is necessary, or at least one that allows 
 the work to run free without any shake. In the second 
 place, the tool must be ground perfectly square, that is, it is 
 not to be ground at an angle like an ordinary cutting tool. 
 Then the rest of the lathe must be smooth on the top, and 
 the operator must have confidence in himself, because if he 
 thinks that he cannot turn perfectly smooth, it will be a long 
 time before he is able to do it. A tool for turning the 
 rounded part of the pillar, if a pattern of this style is de- 
 cided on, is made by boring a hole, the size of the desired 
 curve, in an old file, or in a piece of flat steel, and smooth- 
 ing the hole with a broach and then filing away the steel. 
 The shoulders should be smooth and flat, or a very little 
 undercut, and the ends of the pillars should be rounded as 
 is shown in Fig. 159, because rounded points assist greatly 
 in making the frames go on to the pillars sure and easy, 
 and greatly lessen the danger of breaking a pivot when the 
 clock is being put together. 
 
482 THE MODERN CLOCK. 
 
 When a washer is used the points of the pillars project 
 half the thickness of the washer through the frames, the 
 hole in the washer being large enough to go on to the 
 points of the pillars. 
 
 Figure 160 is an outline of the cock required for the pal- 
 let arbor, and the only cock that will be required for the 
 regulator. It is customary, in some instances, to use a 
 cock for the scape-wheel and also for the hour-wheel arbors, 
 
 Fig. 160 
 
 but for the scape-wheel arbor I consider that a cock should 
 never be used when it can be avoided. The idea of using 
 a cock for the scape-wheel arbor is to bring the shoulder 
 of the pivot near to the dial and thereby make the small 
 pivot that carries the seconds hand so much shorter; and 
 so far this is good, but then the distance between the shoul- 
 ders of the arbor being greater, when a cock is used the 
 arbor is more liable to spring and cause the scape-wheel to 
 impart an irregular force to the pendulum through the pal- 
 lets. This is the reason why I prefer not to use a cock 
 except when the design of the case is such that long dial 
 feet are necessary,' and renders the use of a cock indispen- 
 sable. In the present instance, however, the dial feet are 
 no longer than is just necessary to allow for a winding 
 square on the barrel arbor, and therefore a cock for the 
 scape wheel is superfluous. It is better to use a long light 
 socket for the seconds hand than put a cock on the scape- 
 wheel arbor in ordinary cases. Except for the purpose of 
 uniformity a cock on the hour wheel is always superfluous, 
 although its presence is comparatively harmless. The front 
 pivot of the hour-wheel axis can always be left thick and 
 
THE MODERN CLOCK. 483 
 
 Strong enough should the design of the case require the dial 
 feet to be extra long. 
 
 For the pallet arbor, however, a cock is always necessary, 
 and it should always be made high enough to allow the 
 back fork to be brought as near to the pendulum as possi- 
 ble, so as to prevent any possibility of its twisting when 
 the power is being communicated from the pallets to the 
 pendulum. This cock should be made about the same thick- 
 ness as the frames, and about half an inch broad. ]\Iake the 
 pattern out of a piece of hard wood, either in one solid 
 piece or by fastening a number of pieces together. The 
 pattern should be made a little heavier than the cock is re- 
 quired to be when finished, and it should also be made 
 slightly bevelled to allow it to be easily drawn from the 
 sand when preparing the mould for casting. After it is 
 cast the brass should be hammered carefully, and then filed 
 square, flat, and smooth. 
 
 Screws are better and cheaper when purchased, but they 
 may be made of steel or brass rod by any workman who is 
 provided with a set of fine taps and dies. If purchased thev 
 should be hardened, polished and blued before using them 
 in the regulator. The threads of screws vary in proportion 
 to the size of the screw and the material from which it is 
 made. A screw with from 32 to 40 turns to the inch, and a 
 thread of the same shape as the fine dies for sale in the tool 
 shops make, is well adapted for the large screws in a regu- 
 lator. However, it is not threads of the screws I desire to 
 call attention to so much, although it must be admitted that 
 the threads are of primary importance. It is the shape of 
 the heads and the points which is too often neglected. 
 
 A thread, or a thread and a half, cut down on the point 
 of a screw, will allow it to enter easier than when the point 
 is flat, round, or shaped like a center. This is not a new 
 idea for making the points of screws, but the plan is either 
 not known to many, or it is not practiced to the extent it 
 ought to be. 
 
484 THE MODERN CLOCK. 
 
 The shape of the head of a screw should also always be 
 based on utility, and the shape that will admit of a slit into 
 it that will wear well should be selected. A round head 
 ought never to be used, because a head of thit shape does 
 not present the same amount of surface to the screwdriver 
 that a square head does. It is the extreme end of the slit 
 that is most effective, and in round-headed screws this part 
 is cut away and the value of the head for wearing by the 
 use of the screwdriver is the same as if the head of the 
 screw was so much smaller. A chamfered head may suit 
 the tastes of some people better than a perfectly flat head, 
 but in a head of this shape the slit must be cut deeper than 
 in a square head, because the chamfered part of the head is 
 of little or no use for the screwdriver to act against. The 
 slits should always be cut carefully in the center of the head 
 and the sides of the slit filed perfectly flat with a thin file 
 and the slight burr filed off the edge to prevent the top of 
 the head getting bruised by the action of the screwdriver. 
 The shape of the slit which is best adapted for wearing is 
 one slightly tapered, with a round bottom. The round bot- 
 tom gives greater strength to the head, and prevents the 
 heads of small screws from splitting. 
 
 I have dwelt at some length on these little details because 
 a proper attention to them goes a long way in the making 
 of a clock in a workmanlike manner, and it is desirable that 
 the practical details should be as minute as possible. 
 
 The construction of the barrel is a subject which requires 
 a greater amount of consideration than is sometimes be- 
 stowed upon it. We often meet with regulator barrels 
 which have considerable more brass put into them than is 
 necessary. The value of this extra metal is of little or no 
 consequence. It is the unnecessary pressure the weight of 
 it causes on the barrel pivots, and the consequent increase 
 of friction, which is objectionable. For this reason the 
 weight of the barrel, as v^ell as the weight of every other 
 part of the clock that moves on pivots, should be made no 
 
THE MODERN CLOCK, 
 
 485 
 
 heavier than is absohitely necessary to secure the required 
 amount of strength. In every, instance, except when the 
 diameter is required to be very small, the barrel should be 
 made of a piece of thin brass tubing with two ends of cast 
 brass fastened into it. 
 
 Figure 161 is a sectional view of the ends of a barrel; 
 the diagram on the right is the end where the great wheels 
 rest against, and the one on the left is the other end. The 
 insides of both these ends are precisely the same, but the 
 outsides differ a little. It will be observed that there is a 
 
 Fig. 161 
 
 little projection near the hole on the outside of the front 
 end. This projection is left with the view of making the 
 hole in the center longer, and thereby causing this end to 
 take a firmer hold on the barrel arbor. The back end, or 
 the end that the great wh'eels rest against, and where the 
 ratchet teeth are cut, is shaped precisely like the diagram 
 on the right of Fig. 161. If you cannot get brass plate of 
 sufficient thickness for the ends of the barrel they must be 
 cast. 
 
 The patterns for these barrel ends should be made with- 
 out any hole in the center, and in every way heavier and 
 thicker than they are to be when finished, because it is diffi- 
 cult to obtain good and solid castings when the patterns are 
 made thin, although it is by no means impossible to make 
 them so. Like all brass castings used for the clockmaker's 
 purpose, they should be carefully hammered, and, although 
 these pieces are of an Irregular shape, they can be easily 
 
486 THE MODERN CLOCK. 
 
 hammered regularly with the aid of narrow-faced hammers 
 or punches, and with the exercise of a little patience. After 
 hammering, the castings should be placed on a face plate 
 in the lathe, and the tube which is to form the top part of 
 the barrel fitted easy and without shake on to the flanges 
 and the other parts of the castings turned down to the re- 
 quired thickness, and a hole a little less than 0.3 of an inch 
 diameter bored in the center of each before it is removed 
 from the face plate. The tube which is to form the top of 
 the barrel should be no heavier than is just necessary to cut 
 a groove for the cord, and for this regulator it should be 1.5 
 inch diameter outside measurement, 1.5 inch long, and turn- 
 ed perfectly true on the ends. 
 
 The hole in the front end of the barrel, which is the end 
 nearest to the dial, should be broached a little from the in- 
 side, and the other end broached a little larger from the out- 
 side. The reason for broaching the holes in this manner is 
 to cause the thickest part of the barrel arbor to be at the 
 place where the great wheels work, because, in making a 
 barrel for a regulator, it will generally be found that the 
 arbor requires to be thickest in this particular place. The 
 arbor should be made from a piece of fine cast steel a little 
 more than 0.3 of an inch thick, and not less than four inches 
 long. It is always well to have the steel long enough. This 
 steel should be carefully centered and turned true, and of 
 the same size and taper as the holes in the barrel ends. It 
 is not necessary that the barrel arbor should be hardened 
 and tempered, except on special occasions. In most cases 
 it will last as long as any other part of the clock if it is left 
 soft, and it is much easier to make when soft. Before fit- 
 ting the arbor to the barrel ends it is well to place the ends 
 into the tube that is to form the top of the barrel, because 
 a better fit can be made in this way than when each is fitted 
 separately. When the arbor has been fitted, a good and 
 convenient way of fastening it together is, to use soft solder. 
 It can be easily heated to the required degree of heat with 
 
THE MODERN CLOCK. 487 
 
 the blow-pipe. A very little solder is sufficient for the pur- 
 pose, and if the joints have been well fitted the solder will 
 not show when the work is finished. Care should be taken 
 to notice that the solder adheres to the arbors properly. 
 Perhaps it would be well to mention here that, should the 
 clockmaker not have access to a cutting engine with con- 
 veniences attached to it for cutting the barrel ratchet after 
 the barrel has been put together, the ratchet should be cut 
 first. 
 
 When the different pieces which constitute a barrel have 
 been fastened together the brass work has next to be turned 
 true, and the grooves cut for the cord to run in. It is best 
 not to turn anything off the arbor till the grooves are cut, 
 because they are usually cut smoother v/hen the arbor is 
 strong. The most important points to notice when turning 
 a barrel is to be sure that the top is of equal diameter from 
 the one end to the other, and that the bearing wdiere the 
 great wheels rest against are perfectly true, because, if the 
 top of a barrel is of unequal thickness, the weight will piill 
 with unequal force as it runs down, and if the bearing on 
 the end be out of truth the great w^heels will also be very 
 liable to get out of truth, as their position on the barrel is 
 altered by winding the clock up. 
 
 The shape of the outside of the barrel ends, as is rep- 
 resented in Fig. 161, will be found to be good and service- 
 able. AA is the bearing for the great wheels to rest against ; 
 BB is where the ratchet teeth are to be cut. There must 
 be a little turned off the face of BB, as is shown in the dia- 
 gram, so as to prevent the great wheel from rubbing on 
 the teeth. The space between AA and the barrel arbor is 
 turned smooth. 
 
 Although it is by no means an absolute necessity to have 
 a groove cut in the top of the barrel, yet it is extremely de- 
 sirable that there should be one, so that the cord may al- 
 ways be guided with certainty as the clock is w^ound up. It 
 has long been a disputed question whether the cord should 
 
^SS UiE I.I ODE KM C1.0CK. 
 
 be fastened at the front end of the barrel and wind towards 
 the back, or whether it should be fastened at the back and 
 wind towards the front. I am not aware that there is any 
 violation of principle, so far as the regularity of the power 
 is concerned, whether the cord runs one way or the other. 
 I understand it to be solely a question of keeping the weight 
 clear of the case and the pendulum ball. In ordinary con- 
 structed regulator cases this object will be best attained by 
 cutting the screw so that the cord can be fastened at the 
 front of the barrel and wind towards the back; because in 
 making it in this way, the weight is the length of the barrel 
 farther away from the front of the case when it is wound 
 up, and about the same distance farther away from the 
 pendulum ball when it is nearly run down, than if the cord 
 was fastened at the back end of the barrel and wound 
 towards the front. The cutting of the groove is usually 
 done in an ordinary screw cutting lathe. 
 
 In making the pivots on a barrel it is the usual custom to 
 make the back pivot smaller than the front one but, with 
 all due respect for this time-honored custom, I would di- 
 rect a little attention to the philosophy of continuing to 
 make the barrel pivots of a regulator in this manner. Fric- 
 tion varies with pressure ; a large pivot has a greater 
 amount of friction than a smaller one, because the pressure 
 on the sliding surface of the revolving body is farther away 
 from the center of m.otion in one case than in the other. 
 In regulators where the barrel pivots are of a different size, 
 the effective force of the weight will vary slightly accord- 
 ing as the weight is fully wound up or nearly run down. In 
 one instance the pressure of the weight is more directly on 
 the large pivot than it is on the smaller one; and in the 
 other instance the pressure is more directly on the small 
 pivot than it is on the larger one, and when the weight is 
 half wound up,. or half run down,^ the pressure is equal on 
 both pivots. 
 
THE MODERN CLOCK. 489 
 
 In the center pinion and in some of the other arbors of a 
 clock, it is sometimes necessary to make one pivot con- 
 siderably larger than the other ; but in these cases 
 the difference in the size of the pivots does not affect the 
 regularity of the transmission of the power, because the 
 pressure that turns the wheel is always at the same point. 
 In a regulator barrel, however, the pressure of the cord and 
 weight shifts gradually from one end of the barrel to the 
 other, as the clock runs down, and when the pivots are of 
 unequal thickness the power is transmitted nearly as ir- 
 regular as if the top of the barrel was slightly conical and 
 both pivots of the same size. For the above reason, I think, 
 that it will be plain to all that in a fine clock both of the 
 barrel pivots should be made of an equal diameter. The 
 front pivot should be made no larger than is absolutely nec- 
 essary for a winding square, and when we take the fact into 
 consideration that a fine clock with a Graham escapement 
 requires considerable less power to keep it in motion than 
 an eight-day marine chronometer does, we may safely con- 
 clude that the winding squares of many regulators of the 
 Graham class might be made smaller. A pivot about 0.2 
 of an inch will secure a sufficient amount of strength. 
 For the reasons mentioned above, the back pivot should be 
 exactly the same diameter, and although the effects of fric- 
 tion will be slightly greater when both pivots are of an 
 equal size, still the force of the weight will be transmitted 
 more regularly, w^hich is the object aimed at. Where the 
 plates are bushed a length of two to three diameters is long 
 enough for the pivot holes. 
 
 The stop works, maintaining powers and general ar- 
 rangement of the great wheel, ratchets and clicks, have 
 been so fully described and illustrated on pages 282 to 290, 
 Figs. 83 to 87, that it would be useless duplication to re- 
 peat them here, and the reader is therefore referred to those 
 pages, for full particulars. This is also the case with the 
 purely mechanical operations of cutting the w^heels and 
 
490 ThK MODERN CLOCK. 
 
 pinions, hardening, polishing, staking, etc. ; all have been 
 fully treated; but there are some further considerations 
 which may be mentioned here. The practical value of mak- 
 ing pinions with very high numbers is very much over- 
 rated. I know of two clocks situated in the same building 
 that are compared every other day by transit observation. 
 They both have Graham escapements and mercurial pendu- 
 lums, and are equally well fitted up, and as far as the eye 
 can detect, they are about equally well made in all the essen- 
 tial points, with only this difference : one clock has pinions 
 of eight, and the other pinions of sixteen leaves, yet for two 
 years one clock ran about equally as well as the other. In 
 fact, if there was any difference, it was in favor of the clock 
 with the eight-leaved pinions. In giving this example, I 
 must not be understood to be placing little value on high- 
 numbered pinions. I know that in some instances they can 
 be used to advantage. The idea that I want to illustrate at 
 present is, that it is not in this direction that we are to 
 search for the means of improving the rates of regulators. 
 
 A pinion as low as eleven leaves can be made so that the 
 action of the tooth will begin at or beyond the line of cen- 
 ters; but as eleven is an inconvenient number to use in 
 clock-work, we may with great propriety decide upon 
 twelve as being a sufficient number of leaves for all the 
 pinions used in a regulator having a Graham escapement. 
 
 In arranging the size of the wheels in a regulator, the 
 diameters of the center and third wheels are determined by 
 the distance between the center of the minute and the cen- 
 ter of the seconds hand circle on the dial. As the dials of 
 regulators are usually engraved after the dial plates have 
 been fitted, and as the position of the holes in the dial for 
 the center and scape wheel pivots to come through deter- 
 mines the size of the seconds circle, it may be well to men- 
 tion here that, for a twelve-inch dial, two and a half inches 
 is a good distance for the center of the minute circle to be 
 from the center of the seconds circle. Consequently the 
 
THE MODERN CLOCK. 49I 
 
 center and third wheels must be made of such a diameter 
 as will raise the scape wheel arbor two and a half inches 
 from the center arbor, and the other wheels must be made 
 proportionably larger, according to the number of teeth they 
 contain. 
 
 We all know what a difficult matter it is to make a cutter 
 that will cut a tooth of the proper shape ; but when the cut- 
 ter is once made and carefully used, we also know that it 
 will cut or finish a great number of wheels without injury. 
 For this reason, those who are contemplating making only 
 one, or at most but a few regulators, will find the work will 
 be greatly simplified by making the wheels of a diameter 
 proportionate to the number of teeth they contain, and for 
 all practical purposes the cutter that cuts or finishes the 
 teeth of one wheel will be sufficiently accurate for the oth- 
 ers. If we make all the pinions with the same number of 
 leaves they will also all be nearly of the same diameter, and 
 may be cut, or rather the cutting operation may without 
 any great impropriety be finished with one cutter. 
 
 An opinion prevails among a certain class of workmen 
 that the teeth of the great wheel and leaves of the center 
 pinion should be made larger and stronger than the other 
 wheels and pinions, because there is a greater strain upon 
 them than on the other. However reasonable this idea may 
 seem, a little consideration will show that in the case of a 
 regulator, with a Graham escapement, where so little mo- 
 tive power is required to keep it in motion, an arrangement 
 of this nature is altogether unnecessary. The smallest teeth 
 ever used in any class of regulators are strong enough for 
 the great wheel ; and if there be a greater amount of strain 
 on the teeth of the great wheel in comparison with the teeth 
 of the third wheel, for example, then make the great wheel 
 itself proportionately thicker, as is usually done, according 
 to the extra amount of strain that it is to bear. The teeth 
 of wheels and the leaves of pinions wear more from imper- 
 fect construction than from any want of a sufficient amount 
 of metal in them. 
 
492 THE MODERN CLOCK. 
 
 If we assume the distance between the center of the 
 minute and the center of the seconds circle to be 2^ 
 inches, and also assume that the clock will have a seconds 
 pendulum, and all the pinions have 12 leaves, and the bar- 
 rel make one turn in 12 hours, then^ the following is the 
 diameter the wheels will require to be, so that the teeth 
 may all be cut with one cutter, and also the number of 
 teeth for each wheel: 
 
 Great wheel 144 teeth. Diameter 3.40 inches for the pitch 
 circumference. 
 
 Hour wheel 144 teeth. Diameter 3.40 inches for the pitch 
 circumference. 
 
 Center wheel, 96 teeth. Diameter 2.26 inches for the pitch 
 circumference. 
 
 Third wheel 90 teeth. Diameter 2. 11 inches for the pitch 
 circumference. 
 
 Scape wheel 30 teeth. Diameter 1.75 inches for the pitch 
 circumference. 
 
 The number of arms or crosses to be put in a wheel is 
 usually decided by the taste of the person making the clock. 
 There is, however, another view of the subject, which I 
 would like to mention. With the same weight of metal a 
 wheel will be stronger with six arms than with four or five, 
 and as lightness, combined with strength, should be the ob- 
 ject aimed at in making wheels, I prefer six arms to four or 
 five for the wheels of a regulator. 
 
 Figs. 157 and 158 are front and side elevations of the 
 proposed regulator m.ovement, showing the size and posi- 
 tion of the wheels, the size of the frames, the positions of 
 the pillars, dial feet, etc. The dotted large circular lines 
 on Fig. 157 show the position the hour, minutes, and sec- 
 onds circles will occupy on the dial. According to the ordi- 
 nary rules of drawing, the dotted lines would infer that the 
 movement is in front of the dial, and perhaps it may 
 be necessary to explain that in the present instance these 
 
THE MODERN CLOCK. 493 
 
 lines are made dotted solely with the view of making the 
 diagram more distinct, and are not intended to represent 
 the dial to be at the back of the movement. A is the barrel, 
 B is the great wheel, which turns once in twelve hours; 
 C is the hour wheel, which works into the great wheel, and 
 also turns once in twelve hours ; D is the center wheel, 
 which turns once in an hour, and carries the minute hand; 
 E is the third wheel, and F is the scape wheel, which turns 
 once in a minute and carries the seconds hand; G is the 
 pallets ; H the pillars, and I is the dial feet ; J is the main- 
 taining power click, and K shows the position of the cord. 
 Neither the hour or great wheels project over the edge of 
 the frame, and it will be observed that a clock of this ar- 
 rangement is remarkable for its simplicity, having only four 
 wheels and three pinions, with the addition of the scape 
 wheel and the barrel ratchets. There are no motion or dial 
 wheels, the wheel C turning once in 12 hours, carrying the 
 hour hand. The size and shape of the frames and the posi- 
 tion of the pillars, allows the dial feet to be placed so that 
 the screws which hold the dial will appear in symmetrical 
 positions on the dial. 
 
 Formerly the term "astronomical" was applied to clocks 
 which indicated the motions and times of the earth, moon, 
 and other celestial bodies, but at present we may take it 
 as indicating such as are used in astronomical ob- 
 servatories. In all essential particulars they are the 
 same as first class watchmakers' regulators, the most 
 obvious departure being that the hour hand is made 
 to revolve only once a day, the dial being divided into 
 twenty-four hours. This only requires an intermediate 
 wheel and pinion in the motion work, and, assuming the 
 hour hand to be driven from the center arbor, there will be 
 the usual hour and minute wheels and cannon pinion. The 
 most suitable ratio for these are ^ and 1/6 = 1/24, and, 
 as any numbers, being multiples, may be used, they may as 
 well be selected so as to be cut with the same tools as the 
 
494 'T^E MODERN CLOCK. 
 
 wheels of the train. Two pinions of 20 and wheels of 80 
 and 120 suit very well ; 20 -f- 80 and 20 -f- 120 = 20/80 X 
 20/120 = 400/9600 = 1/24, and the hands will both go in 
 the same direction. 
 
 Some astronomical clocks show mean solar, and others 
 sidereal time; this requires no structural alteration, merely 
 a little shortening of the pendulum in the latter case, which 
 can be done with the regulating nut. 
 
LIST OF ILLUSTRATIONS. 
 
 Addendum 202, 218, 220 
 
 Angular Motion 103,112 
 
 Automatic Pinion Cutter 245, 247 
 
 Drill 249 
 
 " Wheel and Pinion 
 Cutter... 254 
 
 Calendar, Simple 351 
 
 " Perpetual 354, 356, 358 
 
 Center Distances 105, 111, 202 
 
 Chimes, Laying out - 
 
 370, 421, 422, 423, 424, 425 
 
 Chimes Westminster 372 
 
 Click, Position of _..288 
 
 Cock 482 
 
 Compensated Rod, Steel and 
 
 Zinc 42 
 
 Counter-poising Hands... 443 
 
 Count hook. Position of 305 
 
 Count Wheel Striking Train 
 
 302, 303, 311, 314, 315, 316, 322, 324 
 Cuckoo Bellows and Pipe 328 
 
 D 
 
 Dedendum 202 
 
 Dial Work 295 
 
 Diameters of Wheels, Getting 196 
 
 E 
 
 Eight-day Count Wheel, Time 
 and Striking Trains 299.. -.309 
 
 Eight-day Snail Strike -342 
 
 Electric Chimes... 
 
 —.421,422, 423,424,425 
 
 Electric Clocks, Pendulum 
 
 Driven 377,379,381,382 
 
 Electric Clocks, Weight 
 
 Driven 394, 395, 396,398 
 
 Epicycloid 206, 219, 239 
 
 Escape Wheel, Cutting.. .122, 121 
 " " Drawing to fit 
 
 Pallets lao 
 
 Escapement, Anchor 
 
 — .142,144,145,146,147 
 " Brocot's Visible 
 
 127, 129 
 
 " Cylinder.. 
 
 164, 165, 166, 167, 177, 179, 181, V83 
 Dead Beat 117, 118 
 
 " Drum 148 
 
 " Gravity 
 
 152, 154, 157, 159, 161 
 
 Pin 185, 194 
 
 Pin Wheel 136, 137 
 
 " Recoil 
 
 142. 144, 145, 146, 147 
 to draw the 114 
 
 r 
 
 Friction Springs 294 
 
 G 
 
 Grandfather clocks S52 
 
 H 
 
 Hypocycloid 206 
 
 K 
 
 Keyhole Plates 289 
 
 Lever Escapement for Clocks 193 
 Levers, the Elements of 99, 100, 101 
 
 M 
 
 Maintaining Powers 285, 286,287,291 
 
 495 
 
496 
 
 THE MODERN CLOCK, 
 
 Pallets, Drawing 116 
 
 Pendulum Brackets 32 
 
 - " Mercurial 67, 71, 75 
 
 " Torsion ....92, 93, 94, 95 
 
 Oscillation of 10, 14, 21 
 
 " Rieffler 50,75 
 
 Perpetual Calendar Clocks.. 
 
 354, 356,358 
 
 " Brocot 
 
 ....360, 362, 363,364. 366 
 
 Pinion Drill 251 
 
 Pitch Diameter 202, 218, 219, 220, 239 
 
 Plate, Jeweling .475, 476 
 
 Posts - 480 
 
 Precision Clock Room 453 
 
 Q 
 
 Quarter Chiming Snail Trains 341 
 Quail and Cuckoo Train...322, 324 
 
 Rack, Division of 335 
 
 Regulator Trains 465, 467, 479 
 
 Rounding Up Wheels 220, 224 
 
 s 
 
 Secondary Dials 4l6 
 
 Self Winding Clocks.... 
 
 —.400, 401, 404, 406, 408, 412 
 
 Ship's Bell Train .314, 315, 316 
 
 Slide Gauge Lathe 241 
 
 " Tools 243 
 
 Snail, Laying Out ...337 
 
 " Striking Trains 
 
 333,342,345, 346 
 
 Suspension Springs 84 
 
 Synchronizing Clocks 412,415 
 
 w 
 
 Wheel Cutting Engine 255 
 
 Wiring Systems 386,388 
 
 Wood Rod and Lead Bob 33 
 
 Zinc Bob and Wood Rod^ 
 
 .31 
 
INDEX. 
 
 Addendum 202 
 
 Air, Pressure of 20 
 
 Aluminum, Compensation 
 
 with 48 
 
 Anchor Escapement 141 
 
 Angular Measurement, Pecu- 
 liarities of 102 
 
 Apparent Time 348 
 
 Arbors, Polishing Steel —232 
 
 Straightening Bent -.231 
 
 Arc of Escapment 93,109, 
 
 115, 127, 138, 145, 153, 164, 186, 469 
 Armatures, Adjustment of 389,409 
 
 Astronomical Clocks 493 
 
 •• Day 348 
 
 Auxiliary "Weights, 37 
 
 Balance, Vibrations of 180 
 
 Banking... ..90, 156, 160, 170, 176 
 
 Barometric Error 20 
 
 Barrels—. 244,267,465,485 
 
 " Chiming 370 
 
 Batteries 380 
 
 " Dating 392 
 
 Grading .384 
 
 Making... 383 
 
 " Position of ..385 
 
 " Wiring, Methods of 385 
 
 Beat, to put a Clock in.. 89 
 
 Bells .369 
 
 •' Ships 315 
 
 Brocot's Calendar 359 
 
 " Visible Escapement 
 
 127,128 
 
 Bushing 476 
 
 Cables, Clock 269 
 
 •• Lengths of... 271 
 
 Calculations of Weights 57 
 
 Calendars 347 
 
 Brocot's 359 
 
 Gregorian ..349 
 
 Julian 349 
 
 " Perpetual 353 
 
 *' Simple 350 
 
 Carillons 372 
 
 Case Friction -.. 448 
 
 '* Temperature 450 
 
 Cases 446 
 
 Gilding 459 
 
 Marble 460 
 
 to Polish 461 
 
 Polishing .. 457 
 
 " Precision Clock 447 
 
 Regulator 463 
 
 " Restoring old ..455 
 
 Cement for Marble 460 
 
 for Dials 438 
 
 Center Distances 110, 200 
 
 " of Gravity 18 
 
 of Oscillation 13 
 
 Springs 96,294 
 
 Chain Drives 271 
 
 Cheap Clocks, to clean - 187 
 
 Chime Barrels, to mark 371 
 
 Chimes 339,370 
 
 Cambridge 372 
 
 Carillon 372 
 
 Electric.-.: 420 
 
 Tubular 374,422 
 
 Circle, Pitch 202 
 
 Circular Error 21 
 
 Pitch 215 
 
 Cleaning Cheap Clocks 187 
 
 Clocks, Astronomical 493 
 
 Cuckoo 319, 321 
 
 '• Designing -8 
 
 " Four-hundred day 91 
 
 497 
 
498 
 
 THE MODERN CLOCK. 
 
 Clocks, Glass of.. - 4fi2 
 
 Repeating ....332 
 
 •' Room 452 
 
 Cock ._. .-..482 
 
 Collets..- .- 234 
 
 Compensated Pendulum Rocts 40 
 
 Rod, Flat .^1 
 
 " Rods, Tubular. -48 
 
 Compensation . 450 
 
 Compensating Pendulums.... 23 
 
 Bracket for 32 
 
 Compensating Pendulums, 
 Principles of Construc- 
 tion 27 
 
 Compensating Pendulums 
 
 with shot ._ - 36 
 
 Compensating Pendulums, 
 
 Wood Rod and Lead Bob .... 32 
 Compensation Pendulums, 
 
 Wood Rod and Zinc Bob. -28 
 Compensation Pendulums, 
 
 Aluminum 48 
 
 Cones, Rusting of 190 
 
 Construction of Dials 426 
 
 Contacts, Dial 423,425 
 
 Electric ...396 
 
 Contrate Wheel. ..- 171, 375 
 
 Conversion, Table of 18 
 
 Cords 2C8 
 
 " Lengths of 270 
 
 Count Hook ..301, 304, 310 
 
 *• Wheel 301,304,315 
 
 " '* Train 300 
 
 Crown Wheel 171 
 
 Crutches 87, 472 
 
 Cuckoo, Adjustments of 326 
 
 Bellows 328 
 
 " Clock, Names of 
 
 Parts 323 
 
 " Motion Work 296 
 
 Repairing .327 
 
 Cutters for Clock Trains 196 
 
 Setting 197 
 
 Cycloid ...21 
 
 Cylinder Clocks, Examina- 
 
 tion of 171 
 
 Cylinder, End Shake 170 
 
 " Propor- 
 tion of 149 
 
 Side Shake 167 
 
 •* Teeth, Shape of... .183 
 
 Cylinders, Weight of 37 
 
 D 
 
 Day, Astronomical 348 
 
 Sidereal... 318 
 
 " Solar 348 
 
 Dedendum 202 
 
 Denison Escapment 150 
 
 Depolarizers 3S1 
 
 Depthing 200 
 
 " Tool ...477 
 
 Designing Clocks 8 
 
 Detached Lever Escapement 184 
 
 Dials, Construction of 426 
 
 " Contacts.- 423,425 
 
 " Enamel for .431 
 
 " Phosphorescent ..437 
 
 Repairing 432,438 
 
 •' Secondary 417 
 
 to Clean 436 
 
 " " Silver 434 
 
 " Varnish for... 438 
 
 Distances, Center ...200 
 
 Drawings, to read 98 
 
 Draw of Teeth 191 
 
 Drill, Pinion 249,251 
 
 Drop... 1 107 
 
 E 
 
 Effect of Temperature 62 
 
 Eight Day Trains 299 
 
 Electric Chimes .420 
 
 " Clocks 376 
 
 " " Synchronizing 
 
 400,413 
 
 " Contacts 396 
 
 Elements, Mechanical .98 
 
 Enamel for Dials... 431 
 
 End Shake, of Cylinder.. .170, 175 
 
 End Stones .... 477 
 
 Epicycloid 206 
 
 Equation of Time ..365 
 
 Error, Barometric 20 
 
 " Circular 21 
 
 " Temperature 22 
 
 Escape Wheel, Sizes of 109, 
 
 .-.133, 155, 164 
 '• " To make.- 
 
 109, 120, 135, 138, 
 150,155,162,161 
 
THE MODERN CLOCK. 
 
 499 
 
 Escapement, Brocot's 127, 128 
 
 Cylinder 163 
 
 " Denison 150 
 
 " Detached Lever 184 
 
 Drum 148 
 
 Graham 109 
 
 Gravity 150,161 
 
 •• LePaute's Pin 
 
 Wheel 135 
 
 Pin 185,193 
 
 Recoil - lil 
 
 " TodrawGrahamll3 
 
 " Pin Wheel 138 
 " Gravity -.152 
 " Western Clock 
 
 Mfg. Co 193 
 
 Examination of Cylinders — 171 
 Expansion of Metals 22 
 
 F 
 
 Fan 308,326 
 
 Fly for Gravity Escapement--158 
 
 Frames, Making.-- 261 
 
 Thickness of 474 
 
 Four-hundred Day Clocks 91 
 
 Friction, Disengaging..-. 203 
 
 " Engaging 203 
 
 of Teeth... 132 
 
 " Springs- 294 
 
 G 
 
 Gathering Pallet 338,344 
 
 Gilding 459 
 
 Gong Wires 369 
 
 Graham Escapement 109,467 
 
 Gravity, Center of 18 
 
 " Escapement 150 
 
 Gregorian Calendar 349 
 
 H 
 
 Half Hour Striking Work 
 
 334,312,345 
 
 Hammers ..367 
 
 Hardening.. .198, 480, 482 
 
 Springs .—368 
 
 Tail 298,301 
 
 Hands 439 
 
 " Proportions of 440 
 
 " To Balance 442 
 
 •* To Blue 444 
 
 Hour Rack 335 
 
 " Snail - 296,334 
 
 " Strike 342 
 
 '• Wheel.- 96, 293, 2^r,. 325 
 
 Ilypocycloid Curves 206 
 
 Iron, Expansion of 57 
 
 Information, Need for 3 
 
 Isochronism 469 
 
 Jeweling-. 475,477 
 
 Jewels, Pallet 126 
 
 Julian Calendar 349 
 
 Lantern Pinions .-- 235 
 
 Lathe, Slide Gauge—. 241, li43, 246 
 
 Laws of Pendulums .^..11 
 
 Lead 22,32 
 
 Leap Year.. 349 
 
 Length of Pivots.... ..199 
 
 Lepaute's Escapement 135 
 
 Leverage of Wheels 99 
 
 Lift- 106 
 
 Lifting Cam .-.301,331 
 
 Piece ----331 
 
 Planes 116 
 
 Pins 186 
 
 Lock 107 
 
 Locking Hook 301 
 
 Losing Time 192 
 
 Lunation 365 
 
 M 
 
 Magnets, Arrangement of 
 
 378, 386, 389, 395, 401, 406 
 
 Mainsprings 272, 274, 277, 278, 
 
 279, 280,281,282 
 
 Breakage of 281 
 
 Buckled 277 
 
 " Cleaning 277 
 
 Clock 288 
 
 Coil Friction... -277 
 
 Fuzee 279 
 
 " Importance of 
 
 Cleaning 274 
 
 Length of 280 
 
500 
 
 THE MODERN CLOCK. 
 
 Mainsprings, Loss of Power. ..274 
 " Maintaining 
 
 Power.— 285,291 
 
 Oiling 278 
 
 " Stop Works 282 
 
 Maintaining Powers 285 
 
 Mean Apparent Time 348 
 
 Mean Time ...348 
 
 Measuring Wheels 195 
 
 Measurement, Angular 102 
 
 Mechanical Elements 98 
 
 Mercurial Pendulums.— 53, 60, 09 
 For Tow- 
 er Clocks 65 
 
 Mercury.. 53,56,66,70 
 
 Metals, Expansion of 22 
 
 Weight of 37 
 
 Millimeters Compared with 
 
 Inches 18 
 
 Minute Jumpers _..-.. 417 
 
 Wheels 96,293,296,325 
 
 Month Clocks 260 
 
 ♦•' Sidereal 349 
 
 " Synodic 350 
 
 Moon, Phases of 365 
 
 •• Train.... 365 
 
 Motion Work 96, 293, 296, 325 
 
 N 
 
 Need for Information 3 
 
 Numbers, Conversion of 201 
 
 Nut, Rating 42,50,66 
 
 o 
 
 Oiling Cables - 269 
 
 Oscillation, Center of 13 
 
 Overbanking 90, 156, 160, 170, 176 
 
 Pallet Jewels 126 
 
 Pallets..l06, 115, 121, 126, 130, 135, 
 -139, 141, 144, 149, 153, 186, 193, 470 
 
 Pallets, To make 119, 126 
 
 Pendulum, Isochronous 470 
 
 Lengths, Table of 
 
 10,16 
 
 Rieffler 49, 75 
 
 Rods 262 
 
 " Compensated .40 
 
 Comi)ensating 23 
 
 Electric Driven... .376 
 
 Pendulum, Laws of 11 
 
 Mercurial 53,60,69 
 
 " Sidereal 493 
 
 " Torsion. ...91 
 
 Perpetual Calendar E53 
 
 Phases of the Moon .365 
 
 Pillars, Making _ 240 
 
 Pinion Drill, Atrtomalic--.249, 251 
 
 Making 227,252 
 
 " " Machine, Auto- 
 
 matic -.245, 247 
 
 Canon 293,294.295 
 
 Depthing 206, 210, 217 
 
 " Facing 233 
 
 " Hardening 229 
 
 " Lantern .235 
 
 " Tempering 230 
 
 *' To Draw. 206 
 
 Pin Escapement -.. ..185.193 
 
 " Wheels 297, 301, 327 
 
 " •* Escapement.. 135 
 
 To... 
 Draw 138 
 
 Pitch, Addendum 216 
 
 " Circle 202 
 
 •' Circular 215 
 
 " Diametral 216 
 
 Pivots 488 
 
 " Length of 199 
 
 " Proportions of 167,173,199,474 
 
 '* Side Shake ...199 
 
 Planes, Lifting 116 
 
 Plates, Clock 198 
 
 " Thickness of 474 
 
 Poising Balance Staffs... 189,190 
 
 Polishing Steel Arbors 232 
 
 Posts, Clock ..478 
 
 Power 264, 265, 266, 267 
 
 " Maintaining 285 
 
 Putting in Beat 89 
 
 R 
 
 Rack, Division of 335 
 
 Striking Work 331 
 
 Ratchet 288 
 
 Rating Nut 42, 50, 66 
 
 With Shot 90 
 
 Reading Drawings 98 
 
 Repeating Clocks 332 
 
 Recoil Escapement 141 
 
 Regulation 79 
 
 Regulator Trains..- 492 
 
THE MODERN CLOCK. 
 
 501 
 
 Regulators, Making 463 
 
 Repairing Dials 432,438 
 
 Resistance Spools 368 
 
 Rieffler Pendulum 49,75 
 
 Rounding Up 174,221,223 
 
 "Rules for 226 
 
 Run 108 
 
 Rusting of Cones 190 
 
 S 
 
 Screws, Clock 483 
 
 Secondary Dials 417 
 
 Self-winding Clocks 376 
 
 Ship Bells, Striking 313 
 
 Shot, Rating with •.SO 
 
 Sidereal Day — -348 
 
 Month 349 
 
 Pendulums - 4S3 
 
 Year —.349 
 
 Side Shake, Cylinder —167 
 
 " For Pivots 199 
 
 Silvering Dials 434 
 
 Simple Calendar 350 
 
 Sizes of Teeth —.211,213,237 
 
 " " Wheels... COl 
 
 Slide Gauge Lathe 241,243,244 
 
 Snail......... '^96, 33') 
 
 " Division of 337 
 
 " French System 342 
 
 •• Quarter Striking Work. ..339 
 
 " Striking Work .330,340 
 
 Solar Day— - 348 
 
 Sparking, to Prevent — 386 
 
 Springs, Center 294 
 
 Clock 273,288,307 
 
 " Friction.. 294 
 
 Hammer 368 
 
 Main 272,273,274, 
 
 .—277, 278, 279, 280, 282, 307 
 
 Squares, Milling...... -..261 
 
 Standards, Importance of 26 
 
 Star Wheel 332,335 
 
 Steel, Expansion of 57 
 
 Stop Works 282 
 
 Straightening Bent Arbors — 231 
 Striking from Center Arbor. -.298 
 
 To Correct 306,307 
 
 '• ■ Trains.297, 308, 313, 323, 330 
 " " Half Hour... 
 
 ...298, 308, 313 
 " " Setting Up. - 
 
 .-.-307, 310, 339 
 
 Striking Trains, To Calculate. 297 
 
 Rack 331 
 
 Work, Repeating .. .332 
 
 Snail 330,340 
 
 Supports, Pendulum — 86 
 
 Suspension 81, 93 
 
 " Springs 82,93 
 
 Synchronizing 400,413 
 
 Synodic Month 350 
 
 T 
 
 Table, Lengths of Pendulum 
 
 12,16,17,34,258 
 
 " of Expansions 30 
 
 " " Inches, Millimeters 
 
 and French Lines. .18 
 
 " " Time Trains 258, 
 
 339, 340,492 
 
 " " Weights and Metals.37 
 
 Tangent 104 
 
 Teeth, Friction of 132 
 
 Shape of Cylinder 183 
 
 " Shapes of.. 203 
 
 Sizes of 2.1, 213,237 
 
 Temperature, Effect of..- 62 
 
 Error 22 
 
 Tempering 229 
 
 Time, Apparent 348 
 
 " Equation of 365 
 
 " Losing.. 192 
 
 Mean... 348 
 
 To Draw Anchor Escapement 
 
 143, 145, 147 
 
 Top Weights 39 
 
 Torsion Pendulums 91 
 
 Tower Clock, Cables .269 
 
 " " Dials, Sizes of.. .426 
 " " Gravity Escape- 
 ment for 150 
 
 Hands ..442 
 
 " " Maintaining 
 
 Powers.. -285, 291 
 Motion Work--.-295 
 
 " " Pendulums 65 
 
 Stop Works 2S7 
 
 *' " Suspension 65 
 
 t< Time Trains 258 
 
 Trains 330 
 
 Electric 389 
 
 Regulator 492 
 
 " 'Table of 258 
 
 " To Calculate— .257, 264, 297 
 
502 
 
 THE MODERN CLOCK. 
 
 Tropical Year 3*8 
 
 Tubular Chimes 374, 422 
 
 Turning Tools 481 
 
 Y 
 
 Varnish for Dials 438 
 
 •* Remover .456 
 
 Vibrations of Balance 180 
 
 w 
 
 Warning-. 306,312 
 
 Pin 306,312 
 
 Wheel 306,312 
 
 Weight Cords 268 
 
 Weight of Lead, Zinc and 
 
 Cast Iron Cylinders 37 
 
 Weights 265, 319 
 
 " Auxiliary 37 
 
 " Calculations of 27 
 
 Top 39 
 
 Wheel Contrate 171,375 
 
 Crown 171 
 
 Hour 296 
 
 Cutting 254 
 
 Leverage of 99 
 
 Measuring 195 
 
 Minute 96, 293, 296, 325 
 
 Sizes of 201, 490 
 
 Stamping 256 
 
 Star—-.-. 332, 335 
 
 Stretching 226 
 
 Wires, Gong 369 
 
 Y%ar , I 348 
 
 " Leap 349 
 
 " Sidereal ..349 
 
 " Tropical.. 348 
 
 z 
 
 Zinc 54 
 
 .-^xC^t^-C--^- 
 
BIG BEN Is the first and 
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 Big Ben is a beautiful thin 
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 He is fitted with big strong 
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 heavy hands and a large open 
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 Big Ben rings just when you 
 
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 Big Ben is rigidly inspected, 
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 We pay his railroad fare on 
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 we brand him with your name 
 in lots of 24. 
 
 Height 7 inches. Dial 4/4 inches. Intermittent or Long: Alarm. 
 Dealers' names printed free on dials in lots of 24. 
 Freight allowed on orders for one dozen or more. - 
 
 Western Clock Mfg. Co< 
 
 New York 
 
 La Salle, Illinois 
 
 Chicago 
 
 503 
 

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 C I, Jj >^ 01 
 
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 ll||sa 
 
 G^ 
 
 
 504 
 
SELF WINDING CLOCK CO 
 
 NEW YORK 
 
 Self Winding Synchronized Clocks, 
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 Railroads, Public and Office Buildings, 
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 Self Winding Program Instruments, 
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 Tower, Post and Bracket Clocks. 
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 a specialty. 
 
 Hourly signals of correction from the U. S. 
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 505 
 
Tools, Materials 
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 506 
 
In 1854 
 
 Waltham Watches 
 
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 Since that time the burden of proof 
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 17,000,000 WALTHAM WATCHES 
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 507 
 
Howard Clocks 
 
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 I!i£ £• Howard Clock Co. 
 
 BOSTON, NEW YORK AND CHICAGO 
 
 Makers of Clocks but only of the highest grade in their 
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 Jewelers' regulators, electric 
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 508 
 
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 The Best Seven Jewel Watch 
 
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 The first watch guarantee 
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 while selling nearly nineteen 
 million Ingersoll watches, we 
 have been asking: "Why are 
 expenslue^je^weled watches not 
 guaranteed?" 
 
 The Ingersoll-Trenton is the first and only 
 high grade 7-iewel watch made complete and 
 cased in one factory ; and therefore, the only 
 one that can be guaranteed by its makers; 
 others are assembled from movements made in 
 one factory and cases from another, by the 
 dealer, often a competent jeweler, but often, 
 too, without facilities such as the adjusting- and 
 timing synems existing in our complete -watch 
 factory. 
 
 The "I-T" has all features of the most re- 
 cent, costly watches, which secure accuracy. 
 "l-T" gold-filled cases contain gold enough to 
 outlive their guarantees. Sold only through 
 responsible jewelers, who buy direct. If not on 
 sale in your town we will send, prepaid ex- 
 press, on receipt of price. 
 
 INGERSOLL WATCHES 
 
 For seventeen years there has been but one standard in everj^day watches; "Ingersolls" 
 have popularized the very use of watches. One friend says, "They have made the dollar 
 famous." They have never been so worthy of their great reputation as today. Fully guaran- 
 teed. They include; The Dollar Watch; the "Eclipse" at S1.50; the new thin model 
 "Junior" at S2.00; and the "Midget" ladies' size at S2.00. Sold by 60,000 dealers orpost- 
 paid by us. 
 
 ROBERT H. INGERSOLL & BRO. 
 
 New York Chicago London San Francisco 
 
 509 
 
THE GREAT 
 AMERICAN 
 CATALOGUE 
 
 Have you added this Salesman to 
 your selling force ? 
 
 Purchasing Goods from the Great 
 American Catalogue insures prestige 
 and the confidence your customers 
 will bestow upon you will be apparent 
 in increased patronage. 
 
 Our Catalogue meets with cordial 
 approbation of old stand-by customers 
 who are in a position to judge of the 
 meritorious results obtained through 
 constant use, as the best purchasing 
 medium. 
 
 Please permit us to send you a copy. 
 
 The Oskamp-Nolting Co. 
 
 No. 411-413-415-417 ELM ST, 
 Cincinnati :: :: :: Ohio. 
 
 510 
 
MOSELEY 
 
 Made Continuously 
 for over 30 years 
 
 Imitated — but 
 NEVER EQUALED 
 
 The Standard of Excellence 
 
 Nothing is overlooked in their manufacture and no 
 expense is spared to make them RIGHT. The Genuine 
 Moseley Lathe of to-day is the result of years of painstak- 
 ing, systematic and skilled endeavor to satisfy the exact- 
 ing requirements of the most critical and experienced 
 workmen. 
 
 Moseley Chucks are of the best quality, and are made 
 in all sizes; covering every need of the Watchmaker and 
 Repairer. These Chucks and Lathes were manufactured 
 by us for years under the direct supervision of CHAS. S. 
 MOSELEY, the inventor of the "Split Chuck" and" Draw- 
 n-Spindle." 
 
 Moseley Lathes and Attachments, with plenty of Mose- 
 ley Chucks are the secret of rapid and accurate work. 
 They increase your earning power by enabling you to do 
 more work in a day. As an investment they pay big 
 dividends. 
 
 Write your JOBBER for the NEW MOSLEY 
 
 CATALOG--INSTRUCTION.-REFERENCE BOOK No. 11 
 
 "YOU NEED IT EVERY DAY." 
 
 THERE'S NO LATHE LIKE THE MOSELEY'^ 
 
 511 
 
Clock Tools and Clock Materials 
 form an important and extensive 
 item of stock in our Tool and 
 Material Department, at 
 
 PRICES THAT DEFY COMPETITION 
 
 No. 2979. Clock Main Spring Winder. 
 Nickel plated, $0.50 
 
 In Clock Springs, we keep the best polished only; 
 our stock consisting of all die most desirable widths 
 on the market. 
 
 If you do not possess our large Tool and Material 
 Catalogue, kindly send us your business card and 
 procure one. 
 
 We can save you time, money and annoyance; we 
 are anxious to make your acquaintance, as we treat 
 our customers with the utmost courtesy and attention. 
 
 A trial order solicited. 
 
 Otto Young & Co. 
 
 Wholesale Jewelers and Importers and Jobbers 
 
 Diamonds, Watches, Clocks, Jewelry, Tools, 
 
 Materials and Optical Goods. 
 
 Hesrw^orth Building, Chicago 
 
 512 
 
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 BOSTON COLLEGE 
 
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 3 9031 01639917 2 
 
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 BOSTON COLLEGE LIBRARY 
 
 UNIVERSITY HEIGHTS 
 CHESTNUT HILL. MASS. 
 
 BcK>ks may be kept for two weeks and may 
 be renewed for the same period, unless re- 
 served. 
 
 Two cents a day is charged for each book 
 kept overtime. 
 
 If you cannot find what you want, ask the 
 Librarian who will be glad to help you. 
 
 The borrower is responsible for books drawn 
 on his card and for all fines accruing on the 
 same. 
 
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