FARM IMPLEMENTS 
 
 AND 
 
 FARM MACHINERY, 
 
 AND THE 
 
 f 
 
 Principles of their Construction and Use 
 
 "WITH 
 
 SIMPLE AND PRACTICAL EXPLANATIONS 
 
 OF THE 
 
 H.ATVS OF MOTION -AJSTD FORCE 
 
 AS APPLIED 
 
 ON THE FARM. 
 
 ^Vith. 887 Illustrations. 
 
 BY 
 
 JOHN J. THOMAS. 
 
 n 
 
 NEW YORK: 
 ORANGE JUDD AND COMPANY, 
 
 245 BROADWAY, 
 
Entered according to Act of Congress, in the year 1S69, by 
 
 JOHN J. THOMAS, 
 
 In the Clerk's Office of the District Court of the United States for the Southern 
 District of New York. 
 
 .^ 
 
 ^iK^ 
 
PREFACE. 
 
 A small treatise, — the basis of the present work, — was 
 originally published in the Transactions of the New York 
 State Agricultural Society for T850, under the title of 
 "Agricultural Dynamics," or the Science of Farm 
 Forces. A revised and greatly enlarged edition, adapted 
 to general use, was afterwards issued in book form, with 
 the name of " Farm Implements." Since the appearance 
 of the earlier editions, great and rapid improvements have 
 been made in farm machinery of nearly every kind ; and 
 the aim of the work in its present form is to supply, so 
 far as its limits will admit, the information eagerly sought 
 by cultivators in relation to all that has proved of value. 
 
 Another principal object has been to present in a simple 
 and intelligible manner, the leading principles of Mechan- 
 ical Science, applied directly in the farmer's daily routine, 
 — that he may know the reasons of success and failure, 
 and not be guided by random guessing. The first portion 
 of the book is chiefly devoted to a practical explanation 
 of these principles. 
 
 Union Springs, N. Y., 1869. 
 
CONTENTS. 
 
 PART L— MECHANICS. 
 CHAPTER I. 
 Introduction. — Value of Farm Machinery — Importance of a 
 
 Knowledge of Mechanical Principles 7-10 
 
 CHAPTER II. 
 General Principles of Mechanics. — Inertia, Experiments and 
 Examples — Inertia of Moving Bodies, or Momentum — East 
 Riding — The Tiger's Leap — Pile Engines— Fly-wheel— Esti- 
 mating the Quantity of Momentum — Compound Motion — 
 Various Examples — Centrifugal Force 10-22 
 
 CHAPTER III. 
 
 Attraction. — Gravitation — Velocity of Falling Bodies — Resist- 
 ance of the Air — Coin and Feather — Galileo's Famous Experi- 
 ment — Cohesion — Soils — Strength of Materials — Capillary 
 Attraction— The Earth a Desert without it— The Ascent of 
 Sap — Centre of Gravity — Experiments — Upsetting Loads — 
 Shouldering Bags— Rocking Bodies 22-42 
 
 CHAPTER IV. 
 
 Simple Machines, or Mechanical Powers.— Law of Virtual 
 Velocities — The Lever — Many Examples of Levers — Esti- 
 mating the Power of Levers — Three-horse Wbiffle-tree — 
 Compound Levers — Weighing Machines — Stump Pullers — 
 A Wild Theory — Wheel and Axle— Examples — Band and 
 Cog-work — The Pulley — Packer's Stone Lifter — The Inclin- 
 ed Plane— Crooked Roads — Power of Locomotives — Good 
 and Bad Roads — The Wedge — The Screw — Knee-joint Pow- 
 er — Lever Washing Machine — Cheese Presses — Rolling Mills 
 
 —Straw Cutters 42-74 
 
 CHAPTER V. 
 
 Application of Mechanical Principles in the Structure of 
 Implements and Machines — Various Examples — Calculating 
 the Strength of Parts 75-81 
 
 CHAPTER VI. 
 
 Friction. — How to ascertain its Amount — Friction on Roads — 
 Resistance of Mud — The Results of the Dynamometer — 
 Width of Wheels — Velocity — Size of Wheels on Roads — 
 Friction Wheels — Lubricating Substances — Friction neces- 
 sary to Existence 81-93 
 
 CHAPTER VII. 
 
 Principles of Draught— Applied to Wagons— To Plows— Comr 
 bined Draught of Animals — Whiffle-trees for Three Horses^ 
 4 
 
 
CONTENTS. V 
 
 Potter's do. — Wier's Single-tree— The Dynamometer— Self- 
 registering do. — Waterman's do. — Dynamometer for Rotary 
 Motion 93-108 
 
 CHAPTER VIII. 
 Application of Labor. — Power of Horses — Of Men — Best Way 
 
 to Apply Strength 108-113 
 
 CHAPTER IX. 
 Models op Machines. — Common Blunders— Works of Creation 
 
 Free from Mistakes 113-115 
 
 CHAPTER X. 
 
 Construction and Use op Farm Implements and Machines 
 — Implements of Tillage. — Importance of Simplicity — 
 Plows — Rude Specimens — Cast-iron and Steel do. — Charac- 
 ter of a Good Plow — The Cutting Edge— Mould- board- 
 Easy Running Plows — Crested Furrow Slices— Lapping and 
 Flat Furrows— How to Plow Well— Fast and Slow Plowing 
 — The Double Michigan— The Subsoil Plow— The Paring 
 Plow— Gang Plow— Ditching Plow— Mole Plow— Coulters 
 — Weed Hook and Chain— Pulverizers— Harrows— Ged- 
 des' Harrows — Scotch do. — Morgan Harrow — Norwegian 
 do.— Shares' do.— Cultivators— Holbrook's— Alden's— Gar- 
 rett's Horse-hoe— Two-horse Cultivators— Sulky do.— Coin- 
 stock's Spader— Clod Crushers— Roller 115-152 
 
 CHAPTER XI. 
 Sowing Machines— Wheat Drills— Bickford and Huffman's do. — 
 Seymour's Broadcast Sower— Corn Plauters — True's Po- 
 tato Planter— Hand Drills 152-157 
 
 CHAPTER XII. 
 Machines for Haying and Harvesting. — Mowing and Reap- 
 ing Machines — Cutter-bar — Combined Machines — Self 
 Rakers— Johnson's do. — Marsh's and Kirby's do. — Dropper 
 — Binders — Marsh's Harvester — Durability and Selection of 
 Machines— Hay Tedders— Bullard's do. — American do. — 
 Horse Rakes— Revolving do.— Sulky Revolvers— Warner's 
 do. — Spring Tooth Rakes — Hollingsworth's do. — Hay 
 Sweep— Horse Forks— Gladding's do.— Palmer's, Myers' 
 Beardsley's, Raymond's — Harpoon Forks — Hay Carriers — 
 Hicks' do.— Building Stacks— Palmer's Hay Stacker— Ray- 
 mond's Hay Stacker— Dcderick's Hay Press— Beater do. — 
 Hay Loaders 158-186 
 
 CHAPTER XIII. 
 Thrashing, Grinding, and Preparing Products. — Value of 
 Thrashing Machines — Endless Chain Power — How to 
 Measure Power of— Churning by Tread Power— Pitt's Ele- 
 
VI CONTENTS. 
 
 vator — Corn Shellers — Burralls', Richards' — Root Washer 
 — Root Slicers — Farm Mills, Allen's, Forsman's — Emery 
 Cotton Gin 186-197 
 
 PART II— MACHINERY IN CONNECTION WITH WATER. 
 
 CHAPTER I. 
 
 Hydrostatics. — Upward Pressure — Measuring Pressure — Cal- 
 culating Strength of Tubes, etc. — Artesian Wells — Determ- 
 ining Pressure in Vessels — A Puzzle Explained — Hydro- 
 static Bellows— Press — Specific Gravities — Table of do. — 
 Weigbt and Bulk of a Ton of Different Substances 198-210 
 
 CHAPTER II. 
 Hydraulics. — Velocity of Water — Discharge of Water through 
 Pipes — Velocity in Ditches — Leveling Ditches — Archime- 
 dean Screw-pumps — For Cisterns — Non-freezing do. — For 
 Deep Wells — Drive Pumps — Chain Pumps — Rotary do. — 
 Suction and Forcing Pump — Turbine Water Wheels — The 
 Water Ram — Water Engines for Gardens — Flash Wheel — 
 Nature of Waves — Size of do. — Preventing Inroads by do. 
 — Cisterns — To Determine Contents of 211-238 
 
 PART III.— MACHINERY IN CONNECTION WITH AIR. 
 
 CHAPTER I. 
 Pressure of Air. — Weigbt of the Atmosphere — Hand Fastened 
 
 by Air — Barometer — Measuring Heights — Syphon 239-245 
 
 CHAPTER II. 
 Motion of Air. — Wiuds — Wind-mills, how Used — Brown's do. 
 — Causes of Wind — Chimney Currents — Construction of 
 Chimneys — To Cure Smoky do. — Chimney Caps — Ventila- 
 tion 245-259 
 
 PART IV.— HEAT. 
 CHAPTER I. 
 
 Conducting Power — Expansion, Great Force of— Experiments 
 with — Steam Engine — do., for Farms — Steam Plows — 
 
 Latent Heat— Green and Dry Wood 260-276 
 
 CHAPTER II. 
 
 Radiation. — Several Examples in Domestic Economy — Dew and 
 
 Frost— Frost in Valleys— Sites for Fruit Orchards 276-280 
 
 APPENDIX. 
 
 Apparatus for Experiments 281-283 
 
 Discharge of Water through Pipes 284 
 
 Velocity of Water in Pipes 284 
 
 Rule for Discharge of Water 285-286 
 
 Velocity of Water in Tile Drains 286 
 
 Glossary 287-296 
 
FARM IMPLEMENTS 
 
 AND 
 
 FARM MACHINERY. 
 
 PART I. 
 
 MECHANICS. 
 
 CHAPTER I. 
 
 INTRODUCTION. 
 
 No farm can be well furnished without a large number 
 of machines and implements. Scarcely any labor is per- 
 formed without their assistance, from the simple opera- 
 tions of hoeing and spading, to the more complex work 
 of turning the sod and driving the thrashing-machine. 
 The more perfect this machinery, and the better fitted to 
 its work, the greater will be the gain derived by the farm- 
 er from its use. It becomes, therefore, a matter of vital 
 importance to be able to construct the best, or to select 
 the best already constructed, and to apply the forces re- 
 quired for the use of such machines to the greatest possi- 
 ble advantage. 
 
8 MECHANICS. 
 
 Nothing shows the advancement of modern agriculture 
 in a more striking light than the rapid improvement in 
 farm implements. It has enabled the farmer within the 
 last fifty years to effect several times the work with an 
 equal force of horses and men. Plows turn up the soil 
 deeper, more evenly and perfectly, and with greater ease 
 of draught; hoes and spades have become lighter and 
 more efficient ; grain, instead of being beaten out by the 
 slow and laborious work of the flail, is now showered in 
 torrents from the thrashing-machine ; horse-rakes accom- 
 plish singly the work of many men using the old hand- 
 rake ; horse-forks convey hay to the barn or stack with 
 ease and rapidity ; twelve acres of ripe grain are neatly 
 cut in one day with a two-horse reaper ; grain drills and 
 planting machines, avoiding the tiresome drudgery of hand 
 labor, distribute the seed for the future crop with even- 
 ness and precision. 
 
 The owner of a seventy-thousand-acre farm in Illinois 
 carries on nearly all his work by labor-saving machinery. 
 He drives posts by horse-power ; breaks his ground with 
 Comstock's rotary spader ; mows, rakes, loads, unloads, 
 and stacks his hay by horse-power ; cultivates his corn 
 with two-horse, seated or sulky cultivators ; ditches low 
 ground, sows and plants by machinery ; so that his labor- 
 ers ride in the performance of their tasks without exhaust- 
 ing their strength with needless walking over extended 
 fields. 
 
 The great value of improved farm machinery to the 
 country at large has been lately proved by the introduc- 
 tion of the reaper. Careful estimate determined that the 
 number of reaping machines introduced throughout the 
 country up to the beginning of the great rebellion, per- 
 formed an amount of labor while working in harvest 
 nearly equal to a million of men with hand implements. 
 The reaper thus filled the void caused by the demand on 
 workingmen for the army. An earlier occurrence of that 
 
VALUE OF FARM MACHINERY. 9 
 
 war must therefore have resulted in the general ruin of 
 the grain interest, and prevented the annual shipment of 
 the millions during that gigantic contest, which so greatly 
 surprised the commercial savans of Europe. 
 
 The implements and machines which every farmer must 
 have who does his work well are numerous and often 
 costly. A farm of one hundred acres requires the aid of 
 nearly all the following; two or more good plows, a 
 shovel-plow, a small plow, a subsoiler, a single and two- 
 horse cultivator, a seed-planter, a grain-drill, a roller, a 
 harrow, a fanning-mill, a straw-cutter, a root-slicer, a farm 
 wagon with hay-rack, an ox-cart, a horse-cart, wheel-bar- 
 row, sled, shovels, spades, hoes, hay-forks and manure- 
 forks, hand-rakes and horse-rakes, scythes and grain- 
 cradle, grain-shovel, maul and wedges, pick, axes, wood- 
 saw, hay-knife, apple-ladders, and many other smaller con- 
 veniences. The capital for furnishing the farms in the 
 Union has been computed to amount to more than five 
 hundred millions of dollars, and as much more is estimat- 
 ed to be yearly paid for the labor of men and horses 
 throughout the country at large. To increase the effect- 
 ive force of labor only one-fifth would, therefore, add an- 
 nually one hundred millions in the aggregate to the profits 
 of farming. 
 
 A knowledge of the science of mechanics is not so well 
 understood among all classes of people as it should be. A 
 loss often occurs from the want of a correct knowledge 
 of mechanical principles. The strength of laborers is 
 badly applied by the use of unsuitable tools, and that of 
 teams is partly lost by being ill adjusted to the best line 
 of draught. We may perhaps see but few instances of 
 so great a blunder as the ignorant teamster committed 
 who fastened his smaller horse to the shorter end of the 
 whiffle-tree, to balance the large horse at the longer end ; 
 yet instances are not uncommon where operations are per- 
 formed to almost as great a disadvantage, and which, to 
 1* 
 
10 ■ MECHANICS. 
 
 a person well versed in the science of mechanics, would 
 appear nearly as absurd. 
 
 It is well worth while to look at the achievements made 
 through a knowledge of mechanical principles. Compare 
 the condition of barbarous and savage tribes with that of 
 modern civilized nations. The former, scattered in com- 
 fortless hovels, subsist by precarious hunting, or on scanty 
 crops raised on patches of ground by means of the rudest 
 tools. The latter are blessed with smooth, cultivated fields, 
 green meadows, and golden harvests. Commerce with 
 its hum of business, extending through populous cities, 
 and along a hundred far-stretching lines of rail-ways, scat- 
 ters comforts and luxuries to millions of homes ; while 
 ships for foreign commerce thread every channel and 
 whiten every sea. The contrast exhibits the difference 
 between ignorance on the one hand, and the successful 
 application of scientific principles on the other. It is our 
 present object to point out to the farmer the advantages 
 which would result from a wide extension, through all 
 classes, of this knowledge, that the opportunities may be 
 continually increased for general improvement. 
 
 CHAPTER II. 
 
 GENERAL PRINCIPLES OF MECHANICS. 
 
 Having briefly pointed out some of the advantages to 
 the farmer of understanding the principles of the ma- 
 chines he constantly uses, we now proceed to an examina- 
 tion of these principles. It will be most convenient to 
 begin with the simpler truths of the science, proceeding, 
 as we advance, to their application in the construction of 
 machines. 
 
INERTIA. — EXPERIMENTS AND EXAMPLES. 
 
 11 
 
 rNERTIA. 
 
 An important quality of all material bodies is inertia. 
 This term expresses their passive state — that is, that no 
 body (not having life), when at rest, can move itself, nor, 
 when in motion, can stop itself. A stone has not power 
 to commence rolling of its own accord ; a carriage can not 
 travel on the road without being drawn ; a train of cars 
 never commences gliding upon the rails without the power 
 of the locomotive. 
 
 On the contrary, a body, when once set in motion, will 
 continue in motion perpetually, unless stopped by some- 
 thing else. A cannon ball rolled upon the ground moves 
 on until its force is gradually overcome by the resistance 
 of the rough earth. If a polished metallic globe were driven 
 swiftly on a level and polished metallic plane, it would 
 Fig. i. continue in motion a long time and 
 
 travel to a great distance ; but still 
 the extremely minute roughness of 
 the surfaces, with the resistance of the 
 air, would continually diminish its 
 speed until finally stopped. A wheel 
 made to spin on its axis revolves un- 
 til the friction at the axis and the 
 impeding force of the air bring it to 
 rest. But if the air is first removed, 
 Fans revolving in a vacuum. Dv means of an air-pump, the mo- 
 tion will continue much longer. Under a glass receiver, 
 thus exhausted, a top has been made to spin for hours, 
 and a pendulum to vibrate for a day. The resistance of 
 the air may be easily perceived by first striking the edge 
 and then the broad side of a large piece of pasteboard 
 against the air of a room. It is further shown by means 
 of an interesting experiment with the air-pump. Two 
 fan-wheels, made of sheet tin, one, a, striking the air 
 with its edges, and the other, b, with its broad faces (fig. 
 
12 MECHANICS. 
 
 1), are set in motion alike; b is soon brought to rest, 
 while a continues revolving a long time. If now they are 
 placed under the receiver of an air-pump, the air exhaust- 
 ed, and motion given to them alike by the rack-work c?, 
 they will both continue in motion during the same period. 
 There is no machinery made by man free from the 
 checking influence of friction and the air; and for this 
 reason, no artificial means have ever devised a perpetual 
 motion by mechanical force. But we are not without a 
 proof that motion will continue without ceasing when 
 nothing operates against it. The revolutions of the planets 
 in their orbits furnish a sublime instance ; where removed 
 from all obstructions, these vast globes wheel around in 
 their immense orbits, through successive centuries, and 
 with unerring regularity, preserving undiminished the 
 mighty force given them when first launched into the re- 
 gions of space. 
 
 To set any body in motion, a force is requisite, and the 
 heavier the body, the greater must be the force. A small 
 stone is more easily thrown by the hand than a cannon 
 ball ; speed is more readily given to a skiff than to a large 
 
 and heavy vessel ; but the same force 
 which sets a body in motion is re- 
 >C quired to stop it. Thus a wheel or a 
 grindstone, made to revolve rapidly, 
 would need as great an effort of the 
 arm to stop it suddenly as to give it 
 u ' sudden motion. An unusual exertion 
 
 Inertia Apparatus. 
 
 of the team is necessary in starting a 
 loaded wagon; but when once on its way, it would 
 require the same effort of the horses to stop it as to back 
 it when at rest. 
 
 The force of inertia is finely exhibited by means of a 
 little instrument called the inertia apparatus (fig. 2). A 
 marble or small ball is placed on a card, c, resting on a 
 concave stand. A spring snap is then made to strike the 
 
INERTIA. — EXPERIMENTS AND EXAMPLES. 
 
 13 
 
 Fig. 3. 
 
 card, throwing it to a distance, but leaving the ball upon 
 the hollow end of the stand. The same experiment may- 
 be easily performed by placing a very small apple or other 
 solid on a card, the whole resting on a common sand-box, 
 or even the hollow of the hand. A sud- 
 den snap with the finger will throw the 
 card away, while the apple will drop into^ 
 the cavity. The following experiment is 
 still more striking : Procure a thread 
 just strong enough to bear three pounds, 
 and hang upon it a weight of two pounds 
 and a half. Another half pound would 
 break it. Now tie another thread, strong 
 enough to bear one pound, to the lower 
 hook of the weight. If the lower thread 
 be pulled gradually, the upper thread 
 will of course break ; but if it be pulled 
 with a jerk, the lower thread will break. 
 If the jerk be very sudden, the lower string will break, 
 even it be considerably stronger than the upper, the in- 
 ertia of the weight requiring a great force to overcome it 
 suddenly. The threads used in this experiment may be 
 easily had. of any desired strength by taking the finest 
 sewing cotton, and doubling to any desired extent. 
 
 This experiment shows the reason why a horse, when 
 he suddenly starts with a loaded wagon, is in danger of 
 breaking the harness ; and why a heavier weight may be 
 lifted with a windlass or pulley having a weak rope, if the 
 strain is gradual and not sudden. For the same reason, 
 glass vessels full of water are sometimes broken when 
 hastily lifted by the handle. When a bullet is fired through 
 a pane of glass, the inertia retains the surrounding glass 
 in its place during the moment the ball is passing, and a 
 round hole only is made; while a body moving more 
 slowly, and pressing the glass for a longer space of time, 
 fractures the whole pane. 
 
14 MECHANICS. 
 
 INERTIA OF MOVING BODIES, OR MOMENTUM. 
 
 Momentum is the inertia of a moving body. When a 
 force is applied to a heavy body, its motion is at first slow ; 
 but the little momentum it thus acquires, added to the ap- 
 plied force, increases the velocity. This increase of velocity 
 is of course attended with increased momentum, which 
 again, added to the acting force, still further quickens the 
 speed. For this reason, when a steam-boat leaves the pier, 
 and its paddle-wheels commence tearing through the wa- 
 ter, the motion, at first slow, is constantly accelerated un- 
 til the increasing resistance of the water becomes equal 
 to the strength of the engine and the momentum.* Were 
 it not for the momentum of moving bodies (inertia exist- 
 ing), no speed ever could be given to any heavy body, as 
 a carriage, boat, or train of cars. 
 
 The chief danger in fast riding, or fast traveling of any 
 kind, is from the momentum given to the traveler. If a 
 rail-way passenger should step from a car when in full mo- 
 tion, he would strike the earth with the same velocity as 
 that of the train ; or if the train at thirty miles an hour 
 should be instantly stopped, the passengers would be 
 pitched forward with a swiftness equal to thirty miles an 
 hour. When a horse suddenly stops, the momentum of 
 the rider tends to throw him over the horse's head. When 
 a wagon strikes an obstruction, the driver falls forward. 
 A case in court was once decided against the plaintiff, who 
 claimed that the defendant had driven against his wa^on 
 with such force as to throw the plaintiff to a great distance; 
 but the fact was shown that by such momentum he him- 
 self must have been driving furiously, and not the defend- 
 ant, and he lost his suit. 
 
 * In ordinary practice, this is not strictly correct, as friction will make 
 some difference. This influence will be more particularly considered on 
 a subsequent page. Its omission here does not at all alter the principle 
 under consideration. 
 
MOMENTUM. EXAMPLES. 
 
 15 
 
 An Eastern traveler once succeeded in saving his life by 
 a ready knowledge of this principle. He was closely pur- 
 sued by a tiger, and when near a precipice, watching his 
 
 opportunity, he threw his coat and 
 hat on a bush, and jumped one 
 side, when the animal, leaping swift- 
 ly on the concealed bush, was car- 
 ried by momentum over the prec- 
 ipice. 
 
 As a large or heavy body pos- 
 sesses greater momentum than a 
 small or light one, so any body 
 moving with great speed possesses 
 more than one moving slowly ; for 
 instance, the momentum of a rifle 
 ball is so great as to carry it through 
 a thick plank, while, if thrown slow- 
 ly, it would scarcely indent it. 
 
 This property of bodies is applied 
 with great advantage to many 
 practical purposes. The momentum 
 of the hammer drives the nail into 
 the wood; for the mere pressure 
 of its weight would not do it, if it 
 were a hundred times as heavy. 
 Wedges are driven by employing 
 the same kind of power. 
 
 On a larger scale, the pile-engine 
 
 operates in a similar manner. The 
 
 ram or weight, h (fig. 4), is slowly 
 
 lifted by means of a pulley and 
 
 wheel-work, worked by the handles or cranks, b b, until 
 
 the arms of the tongs which hold the ram are compressed 
 
 in the cheeks, % i, when it suddenly falls with prodigious 
 
 force on the pile or post to be driven. , In this Avay long 
 
 posts of great size are forced into the mud of swamps and 
 
 Pile Engine. 
 
10 
 
 MECHANICS. 
 
 Fie. 5. 
 
 river bottoms, "where other means would fail. When a 
 steam-engine is used for lifting the ram, the work is more 
 rapidly performed. 
 
 An interesting example of the use and efficiency of 
 momentum is furnished by the water-ram, a machine for 
 raising water, described on a subsequent page. 
 
 The fly-wheel, a large and heavy wheel used to regulate 
 the motion of machinery, derives its value from the power 
 of inertia, or momentum, which prevents the machine 
 from stopping suddenly when it meets with any unusual 
 obstruction. In the common thrashing-machine, it has 
 been found that a heavy cylinder, by acting as a fly-wheel, 
 renders the motion steadier, and less liable to become im- 
 peded by large sheaves of grain. An ignorance of this 
 principle has sometimes proved a serious inconvenience. 
 A farmer, having occasion to raise a large quantity of 
 water, erected a horse-pump ; but at every stroke of the 
 
 pump the animal was sud- 
 denly thrown loosely for- 
 ward, and again jerked back- 
 ward, as the piston fell light- 
 ly and rose heavily. A fly- 
 wheel attached to the ma- 
 chinery would have prevent- 
 ed this unpleasant jerking, 
 and have enabled the horse, 
 straw-cutter with fly-xckcci. ^ conge quence, to accom- 
 
 plish more work. In the pile-driving engine, where a great 
 weight is suddenly thrown loose from a height, the horses 
 would be pitched forward when suddenly relieved of this 
 load but for the regulation of a fly-wheel, the motion of 
 which is not quickly changed, neither from fast to slow nor 
 from slow to fast. 
 
 Where there is a rapid succession of forces required in 
 practice, the fly-wheel is usually of great advantage. 
 Hence its use in all revolving straw-cutters, where the 
 
INERTIA. THE FLY-WHEEL. 
 
 17 
 
 knives make quickly-repeated strokes (fig. 5). More re- 
 cently it has been applied to the dasher-churn (fig. 6), 
 where the rapid upright strokes are so well known to be 
 very fatiguing for the amount of force applied. 
 
 By thus regulating motion, the fly-wheel frequently 
 enables an irregular force to accomplish work which other- 
 wise it could not perform. Thus a man may exert a force 
 equal to raising a hundred pounds, Fig. 6. 
 
 yet, when he turns a crank, there 
 is one part of the revolution where 
 he works to great disadvantage, 
 and where his utmost force will 
 not balance forty pounds. Hence, 
 if the work is heavy, he may not 
 be able to turn the crank, nor to 
 do any work at all. If, however, 
 a fly-wheel be applied, by gather- 
 ing force at the most favorable 
 part of the turning, it carries the 
 crank through the other part. 
 
 An error is sometimes commit- 
 ted by supposing the fly-wheel actually creates power, for 
 as much force is required to give it momentum as it 
 afterward imparts to the machine ; it consequently only 
 accumulates and regulates power. 
 
 On rough roads, the force of inertia causes a severe 
 strain to a loaded wagon when it strikes a stone. The 
 horses are chafed, the wagon and harness endangered, and 
 the load jarred from its place. This inconvenience is 
 avoided in part by placing the box upon springs, which, by 
 yielding to the blow, gradually lessen the effects of the 
 shock. For carts and slowly moving lumber-wagons 
 springs are useful, but more so as the velocity and 
 momentum increase. Even on so smooth a surface as a 
 rail-road, it was found by experiments made some years 
 ago, that when the machinery of a locomotive was placed 
 
 Churn with a fly-wheel, for equal* 
 izinff the motion. 
 
18 MECHANICS. 
 
 upon springs, it would endure the wear and tear of use 
 four times as long as without them. 
 
 For this reason, a ton of stone, brick, or of sand, is harder 
 for a team than a ton of wool or hay, which possesses con- 
 siderable elasticity. 
 
 ESTIMATING THE QUANTITY OE MOMENTUM. 
 
 The quantity of momentum is estimated by the velocity 
 and weight of the body taken together. Thus a ball of 
 two pounds weight moves with twice the force of a one- 
 pound ball, the speed being equal ; a ten-pound ball with 
 ten times the force, and so on. A body moving at the 
 rate of two feet per second possesses twice the momentum 
 of another of equal size with a velocity of only one foot 
 per second. A musket ball, weighing one ounce, flying 
 with fifty times the speed of a cannon ball, weighing fifty 
 ounces, would strike any object with equal force ; or, if 
 they should meet each other from opposite directions, the 
 momentum of both would be mutually destroyed, and 
 they would drop to the earth. 
 
 Where the mass is very great, even if the motion is 
 slow, the momentum is enormous. A large ship floating 
 near a pier wall may approach it with so small a velocity 
 as to be scarcely perceptible, and yet the force would be 
 enough to crush a small boat. When great weight and 
 speed are combined, as in a rail-way locomotive, the force 
 is almost irresistible. This circumstance often insures the 
 safety of the passengers ; for as nothing is capable of 
 instantly overcoming so powerful a momentum, when 
 accidents occur the speed is more gradually slackened, 
 and the passengers are not pitched suddenly forward. A 
 light wagon, rapidly driven, possessing but little compara- 
 tive force, is more suddenly arrested, and the danger is 
 greater. 
 
 When two bodies meet from opposite directions, each 
 
COMPOUND MOTION. 19 
 
 sustains a shock equal to the united forces of both. Two 
 men accidentally coming in contact, even if walking 
 moderately, receive each a severe blow ; that is, if each 
 were walking three miles an hour, the shock would be the 
 same as if one at rest were struck by the other with a 
 velocity of six miles an hour. This principle accounts for 
 the destructive effects of two ships running foul of each 
 other at sea, or of the collision of two opposite trains on 
 a rail-road. 
 
 The preceding principles show that a sledge, maul, or 
 axe will always strike more effective blows when made 
 heavier, if not rendered unwieldy. 
 
 COMPOUND MOTION. 
 
 It often happens that two or more forces act on the 
 same body at the same time. If they all act in the same 
 direction, the effect will be equal to the sum of the forces 
 taken together ; but if they act in opposite directions, the 
 forces will tend to destroy each other. If two equal 
 forces act in contrary directions, they will be completely 
 neutralized, and no motion will be produced. Thus, as 
 an example of these forces — a bird flying at the rate of 
 forty miles an hour, with a wind blowing forty miles an 
 hour, will be driven onward by these two combined forces 
 eighty miles an hour ; but if it undertake to fly against 
 such a wind, it will not advance at all, but remain station- 
 ary. A similar result will take place if a steam-boat, 
 having a speed of ten miles an hour, should first run 
 down a river with a current of equal volocity, and then 
 upward against the current ; in the first case it would 
 move twenty miles an hour, and in the latter it would not 
 move at all. 
 
 Where forces act neither in the same nor in opposite 
 directions, but obliquely, the result is found in the follow- 
 
20 MECHANICS. 
 
 ing manner: If a ball, placed at the point a (fig. 7), be 
 struck by two different forces at the same moment, in the 
 Fi(r 7 direction shown by the two ar- 
 
 rows, and if one force be just suf- 
 ficient to carry it from a to c, 
 and the other to carry it from a 
 to b, then it will move inter- 
 mediate between the two, in the 
 direction of the diagonal of the 
 parallelogram a d, and to a dis- 
 tance just equal to the length of this diagonal or cross- 
 diameter. 
 
 "When the forces act very nearly together, the parallelo- 
 gram of the forces will be very narrow aud quite long, 
 with a long diagonal Fig. 8. 
 
 (fig. 8) ; but if they act 
 on nearly opposite sides 
 of the ball, they will 
 
 very nearly neutralize each other, and the diagonal or re- 
 sult will be very short, showing that the motion given to 
 the ball will be very small (fig. 9). 
 
 These examples show the importance of having teams 
 attached to a plow or to a wagon very nearly in a straight 
 line with the draught, or else a part of the force will be 
 Fig. 9. lost ; and also the impor- 
 
 -^fi tance, when several animals 
 
 are drawing together, of 
 their working as nearly as 
 possible in the same straight line. For, the more such 
 forces deviate from a right line, the more they will tend 
 to destroy or neutralize each other. 
 
 A familiar example of the result of two oblique forces 
 is furnished when a boat is rowed across a river. If the 
 river has no current, the boat will pass directly from bank 
 to bank perpendicularly ; but if there is a current, its track 
 will form a diagonal, and it will strike the opposite bank 
 
CENTRIFUGAL FORCE. 
 
 21 
 
 lower down, according to the rapidity of the stream and 
 the slowness of the boat. 
 
 Another instance is afforded when a ferry-boat is 
 anchored, by means of a long rope, to a point some dis- 
 tance above (fig. 10) ; the boat, being turned obliquely, 
 will pass from one bank to the other by the force of the 
 current. Here the water tends to carry the boat down- 
 Fig. 10. ward, while the 
 
 force of the rope 
 acts upward ; the 
 boat passes be- 
 tween the two 
 from bank to 
 bank. The ascent of a kite is precisely similar, the wind 
 and the string being counteracting forces. When a vessel 
 sails under a side wind, the resistance of the keel against 
 the water, and the force of the wind against the sail, act 
 in different directions, and produce a motion of the vessel 
 between them. 
 
 CENTRIFUGAL FORCE. 
 
 All bodies, when in motion, have a tendency to move 
 forward in a straight line. A stone thrown into the air is 
 gradually bent from this straight course into a curve by 
 the attraction of the earth. When a ball is shot from a 
 gun, the force being greater, it flies in a longer and 
 straighter curve. A familiar example also occurs, while 
 driving a wagon rapidly, in attempting to turn suddenly 
 to the right or left ; the tendency of the load to move 
 straight on will sometimes cause its overthrow. An 
 observance of this principle would prevent the error which 
 some commit by making sharp turns or angles in ditches 
 and water-courses ; the onward tendency of the water 
 drives it against the bank, checks its course, and wears 
 away the earth. By giving the ditch a curve, the water 
 
22 MECHANICS. 
 
 is but slightly impeded, and a much larger quantity will 
 escape through a channel of any given size. 
 
 When a grindstone is turned rapidly, the water upon 
 its surface is thrown off by this tendency to move in 
 straight lines. In the same way, a weight fastened to a 
 cord, whirled by the hand, will keep the cord stretched 
 during the revolution. A cup of water, attached to a 
 cord, may be swung over the head without spilling, the 
 water being held by centrifugal force. The same principle 
 causes a stone, when it leaves a sling, to fly off in a line. 
 This tendency to fly off from a revolving centre is called 
 centrifugal force — the word centrifugal meaning flying 
 from the centre. Large grindstones, driven with great 
 velocity by machinery, are sometimes sj>lit asunder by 
 centrifugal force. 
 
 The most sublime examples of this force occur in the 
 motion of the earth and planets, which will be more fully 
 explained in a future page. 
 
 CHAPTER in. 
 
 ATTRACTION. 
 GRAVITATION. 
 
 The earth, as is well known, is a mass of matter in the 
 form of a globe, the diameter being upward of 7900 miles. 
 From its enormous size and the small portion seen from 
 one point, the surface appears flat, except where broken 
 into mountains and valleys. 
 
 The tendency which all bodies possess of falling toward 
 the earth is owing to the attractive force which this great 
 mass of matter exerts upon them. This kind of attrac- 
 
GRAVITATION". VELOCITY OF FALLING BODIES. 
 
 23 
 
 tion is called gravitation. The force with which a body- 
 is thus drawn is the iceight of that body. 
 
 When a stone is dropped from the hand, its velocity is 
 at first slow, but continues to increase till it strikes the 
 earth ; hence, the further it falls the harder it will strike. 
 This accelerated motion is precisely similar to that of a 
 steam-boat when it first leaves the wharf; the force of 
 gravity may be compared to the driving power of the 
 engine, and the quickened velocity of the falling stone 
 to the increased headway of the boat. 
 
 All bodies, whether large or small, fall equally fast, un- 
 less they are so light as to be borne up in part by the 
 resistance of the air. In the first second of time they fall 
 16 feet; in the second, 3 times 16, or 48 feet ; in the third 
 second, 5 times 16, or 80 feet, and so on. Or, if the whole 
 distance fallen be taken together, they fall 16 feet in one 
 second, 4 times 16 in two seconds, 9 times 16 in three 
 seconds, and so forth. In other words, the whole distance 
 is equal to the square of the time. This is plainly ex- 
 hibited iu the following table : 
 
 Seconds, from beginning 
 to fall. 
 
 1 
 
 2 
 
 3 
 
 4 
 
 5 
 
 6 
 
 Whole height fallen in 
 feet. 
 
 16 
 
 4X16 
 or64. 
 
 9X16 
 or 144. 
 
 16X16 
 or 256. 
 
 7X16 
 or 112. 
 
 25X16 
 or 400. 
 
 36X16 
 or 576. 
 
 Space fallen in each sec- 
 ond in feet. 
 
 16 
 
 3X16 
 
 or 48. 
 
 5X16 
 or 80. 
 
 9X16 
 or 144. 
 
 11X16 
 or 176. 
 
 A stone or other body will fall 1 foot in a fourth of a 
 second, 3 feet the next fourth, 5 feet the third fourth, and 
 7 feet the last fourth ; which is the same as 4 feet in half 
 a second, 9 feet in three-fourths of a second, and 16 feet 
 for the whole second. 
 
 The depth of an empty well, or the height of a preci- 
 pice, may be nearly ascertained by observing the time 
 required for the fall of a stone to the bottom. The time 
 may be measured by a stop-watch, or, in its absence, a 
 pendulum may be made by fastening a pebble to a cord, 
 which will swine: from the hand in regular vibrations of 
 
24 MECHANICS. 
 
 an exact second each if the cord be 39J inches long, or of 
 half a second each if it be about 9f inches long. 
 
 The velocity increases simply as the time, that is, the 
 speed in falling is twice as great in two seconds as in one ; 
 three times as great in three seconds ; four times as great 
 in four seconds, and so forth. A stone will fall four times 
 as far in two as in one second, while its velocity will be 
 doubled ; nine times as far in three seconds, while its 
 velocity will be tripled, etc. 
 
 If a stone is thrown upward, its motion continues 
 gradually to decrease, at the same rate as it increases in 
 falling ; hence the same time is required to reach its 
 highest point, as to fall from that point back to the earth. 
 Therefore the velocity with which it is first projected up- 
 ward is equal to the velocity which it attains at the 
 moment of striking the ground. There is an exception, 
 however, to this general rule. In a vacuum it would be 
 perfectly correct, but in ordinary practice the resistance 
 of the air tends to diminish the velocity while ascending, 
 and still further to retard it while descending. For this 
 reason, it will fall with less speed than it first arose. For 
 heavy bodies and small distances, this exception would be 
 imperceptible ; but with small bodies falling from great 
 heights, the difference will be considerable. 
 
 The velocity of a stone after falling one second, or six- 
 teen feet, is at the rate of thirty-two feet per second; 
 hence, if thrown upward at that rate, it will rise just six- 
 teen feet high. After falling three seconds, the rate is 
 ninety-six feet ; and hence, if projected upward at ninety- 
 six feet per second, it will rise nine times sixteen feet, or 
 one hundred and forty-four feet high. And so of other 
 heights. 
 
 Were it not for the resistance of the air, a feather would 
 fall as swiftly as a leaden ball. This is conclusively shown 
 by an interesting experiment. A tall glass jar (fig. 11), 
 open at the bottom, is covered with a brass cap, fitting it 
 
TELOCITY OF FALLING BODIES. 
 
 25 
 
 Fig. 11. 
 
 air-tight. Through this cap passes an air-tight wire, which, 
 by turning, opens a small pair of pincers. Within these 
 are placed a feather and a half dollar, and the air is then 
 thoroughly drawn from the receiver by means of an air- 
 pump. The wire is turned, and the feather and coin both 
 drop at once, and strike the bottom at the same moment. 
 
 There are many examples showing the accelerated 
 motion and increased force of falling 
 bodies. When a large stone rolls down 
 a mountain, it first moves slowly, but 
 afterwards bounds with rapidity, sweep- 
 ing before it all smaller obstacles. Hail- 
 stones, although small, acquire such veloc- 
 ity as to break windows ; and but for 
 the resistance of the air, they would be 
 much more destructive. The blow of a 
 sledge-hammer is more severe as it is lifted 
 to a greater height. Newton was first 
 led to the examination of the laws of 
 gravity by observing, when sitting under 
 an apple-tree, that the fruit struck his 
 hand with greatest severity when it fell 
 from the top of the tree. 
 
 It is not an unusual error to suppose 
 that a large body will fall more rapidly 
 than a small one. Some can scarcely be- 
 lieve that a fifty-Six pound Weight Will Feather and coin falling 
 
 not drop with a greater velocity than a ^e m a vacuum. 
 small nail, not remembering that a proportionately 
 greater force is required to overcome the inertia and 
 set the larger body in motion. This error existed for 
 many centuries, from the time of Aristotle until Galileo 
 first questioned its correctness. The celebrated ex- 
 periment which established the truth on this subject, 
 and led to the discovery of the laws of falling bodies 
 just explained, and which formed an era in modern 
 
26 MECHANICS. 
 
 philosophy, was performed from the top of the leaning 
 tower of Pisa. Galileo was a philosophical teacher, and, 
 being a man who thought for himself, soon discovered, by 
 reasoning, the errors that had been received without a 
 doubt for more than twenty centuries. All the learning 
 of the age and the wisdom of the universities were against 
 him, and in favor of this time-honored error, the truth of 
 which no one had ever thought of submitting to experi- 
 ment. The hour of trial arrived, when he, an obscure 
 young man, stood nearly alone on one side, while the 
 multitude, with all the power and confessed knowledge 
 of the age, were on the other. 
 
 The balls to be employed were carefully weighed and 
 scrutinized to detect deception, and the parties were satis- 
 fied. The one ball was exactly twice the weight of the 
 other. The followers of Aristotle maintained that when 
 the balls were dropped from the top of the tower, the 
 heavy one would reach the ground in exactly half the 
 time employed by the lighter ball. Galileo asserted that 
 the weights of the balls would not affect their velocities, 
 and that the times of descent would be equal. The balls 
 were conveyed to the summit of the lofty tower — the 
 crowd assembled round the base — the signal was given — 
 the balls were dropped at the same instant, and swiftly 
 descending, at the same moment struck the earth. Again 
 and again the experiment was repeated with uniform 
 results. Galileo's triumph w r as complete — not a shadow 
 of doubt remained; but, instead of receiving the con- 
 gratulations of honest conviction, private interest, the loss 
 of place, and the mortification of confessing false teach- 
 ing, proved too strong for the candor of his adversaries. 
 They clung to their former opinions with the tenacity of 
 despair, and he was driven from Pisa.* 
 
 * Mitchell's Lectures. 
 
COHESION. — EXAMPLES. 27 
 
 COHESION - . 
 
 The attraction of gravitation, as we have just seen, takes 
 place between bodies at a greater or less distance from 
 each other. There is another kind of attraction, acting 
 only when the parts of substances are in actual contact / 
 this is called cohesion. It is this which holds the parts of 
 a body together and prevents it from falling to pieces. It 
 may be shown by taking two pieces of lead, and, after 
 having made upon them two smoothly-shaven surfaces 
 with a knife, pressing them firmly together with a twist- 
 ing motion (fig. 14). The asperities of the surfaces are 
 thus pushed down, and the Fig- 1*. 
 
 particles are brought into 
 close contact, so that cohc- W§ 
 
 Sion immediately takes place Cohesive attracttoiiTn'two lead balls'. 
 
 between them, and some force will be required to draw 
 them asunder.* Two pieces of melted wax adhere to- 
 gether in the same way. Melted pitch or other similar 
 substance, smeared thinly over the polished surfaces of 
 metal or glass, also causes cohesion to take place between 
 them. Smooth iron plates, two inches in diameter, have 
 been made to stick together so firmly with hot grease as 
 to require, when cold, a weight of half a ton to draw 
 them apart. Plates of brass of the same size, cemented 
 by means of pitch, required 1400 pounds. On this prin- 
 ciple depends the efficacy of those substances which are 
 used for cementing broken vessels. 
 
 The most perfect artificial polish which can be given to 
 hard metals is still so rough as to prevent the faces from 
 
 *.That this is not atmospheric pressure, like that which holds two 
 panes of wet glass together, is shown by the fact that it requires nearly 
 as great a force to separate them when the}' are placed under the exhaust- 
 ed receiver of an air-pump. Besides this, atmospheric pressure is much 
 weaker than this force, with so small a surface. 
 
28 MECHANICS. 
 
 coming into close contact; hence they must be either 
 melted, or softened like iron when it is welded. 
 
 The different degrees of cohesion which take place 
 between the particles of various soils, to reunite them 
 after they have been crumbled asunder, occasion the main 
 difference between light and heavy soils. When a light 
 soil becomes soaked with water \ the particles adhere in a 
 very slight degree ; and hence, when it becomes dry again, 
 it is easily worked mellow. But if it be of a clayey 
 nature, too much moisture softens it like melted wax: 
 the particles are thus brought into close contact, and 
 strong adhesion takes place ; hence the hardness and diffi- 
 culty of working such soils when again dried. This ad- 
 hesion is lessened by applying sand, chip-dirt, straw, yard- 
 manure, or by burning the earth, but more especially by 
 thorough draining, which, preventing the clay from be- 
 coming so moist and soft, lessens the adhesion of its 
 parts. 
 
 Different substances are hard, soft, brittle, or elastic, 
 according to the different degrees or modes of action in 
 the attraction of cohesion. 
 
 STRENGTH OF MATERIALS. 
 
 It is a matter of great utility in the construction of 
 machinery to determine the different degrees of cohesion 
 possessed by different substances ; or, in other words, to 
 ascertain their strength. This is done by forming them 
 into rods of equal size, and applying weights to their 
 lower extremities sufficient to break them, by drawing 
 them asunder. The amount of weight shows their rela- 
 tive degrees of strength. The following table gives the 
 weights required to break the different substances, each 
 being formed into q rod one quarter of an inch square : 
 
STEENGTH OF MATEEIAES. 29 
 
 Woods. 
 
 Ash, toughest 1000 lbs. 
 
 Beech 718 « 
 
 Box 1250 " 
 
 Cedar .' 712 " 
 
 Chestnut 656 " 
 
 Elm 837 " 
 
 Locust 1380 " 
 
 Maple 056 " 
 
 Oak, white 718 " 
 
 Pine, white 550 
 
 « pitch 750 " 
 
 Poplar 437 « 
 
 Walnut 487 " 
 
 Metals. 
 
 Steel, best 0370 lbs. 
 
 « soft 7500 « 
 
 Iron, wire 0440 
 
 " best bar 4690 " 
 
 " common bar. . ., 3750 
 
 " inferior bar 1880 " 
 
 it cas t 1150 to 3100 " 
 
 Copper, wire 3S00 
 
 - cast 2030 » 
 
 Brass 2800 " 
 
 Platina wire ooUU 
 
 Silver, cast 2500 
 
 Gold, cast ' !250 " 
 
 Tin 31° " 
 
 Zinc, cast 10° " 
 
 « sheet --1000 « 
 
 Lead, cast 55 
 
 « milled 207 « 
 
 From these tables we may ascertain the strength of 
 chains, rods, etc., when made of different metals, and of 
 timbers, bars, levers, swing-trees, and farm implements, 
 when made of woods. Wood which will bear a very 
 heavy weight for a minute or two, will break with two- 
 thirds of the weight when left upon it for a long time. 
 This explains the reason that store-house and barn timbers 
 sometimes give way under heavy loads of grain, which 
 have appeared at first to stand with firmness. 
 
30 MECHANICS. 
 
 Although the preceding table gives the strength of wood 
 drawn lengthwise, yet the comparative results are not 
 greatly different when the force is applied in a transverse 
 or side direction, so as to break in the usual way. 
 
 The following table shows the results of several experi- 
 ments with pieces of wood one foot in length, one inch 
 square, with the weight suspended from one end, breaking 
 them sidewise. 
 
 White oak, seasoned, broke with 240 lbs. 
 
 Chestnut, " " 170 " 
 
 White pine, " " 135 " 
 
 Yellow pine, " " 150 " 
 
 Ash, « " 175 " 
 
 Hickory, « " 270 " 
 
 A rod of good iron is about ten times as strong as the 
 best hemp rope of the same size. The best iron wire is 
 nearly twenty times as strong as a hemp cord. Hence the 
 enormous strength of the wire cables, several inches in di- 
 ameter, which are employed for the support of suspension 
 bridges. 
 
 A rope one inch in diameter will bear about 5000 lbs., 
 but in practice should not be subjected to more than half 
 this strain, or about one ton. The strength increases or 
 diminishes according to the size of the cross-section of the 
 rope ; thus a cord half an inch in diameter will support 
 one quarter as much as an inch, and a quarter-inch cord a 
 sixteenth as much. A knowledge of the strength of 
 ropes, as used by farmers in windlasses, pulleys, drawing 
 loads, etc., would sometimes prevent serious accidents. 
 The following table may therefore be useful : 
 
 Diameter of rope or Pounds borne Breaking 
 
 cord in inches. with safety. weight. 
 
 One-eighth 31 lbs. 78 lbs. 
 
 One-fourth 125 " 314 " 
 
 One-half 500 " 1250 " 
 
 One 2000 " 5000 " 
 
 One and a quarter 3000 " 7500 " 
 
 One and a half 4500 " 12,500 " 
 
STRENGTH OF MATERIALS. 31 
 
 These results will vary about one-fourth with the qual- 
 ity of common hemp. Manilla is about one-half as strong 
 as the best hemp. The latter stretches one-fifth to one- 
 seventh before breaking. 
 
 Wood is about seven to twenty times stronger when 
 taken lengthwise with the fibres than when a side force is 
 exerted, so as to split it. The splitting of timber or wood 
 for fuel is, however, accomplished with a comparatively 
 small power by the use of wedges, the force of heavy 
 blows, and the leverage of the two parts. 
 
 The attraction of cohesion is very weak in liquids ; it is 
 sufficient, however, to give a round or spherical shape to 
 very small portions or single drops, and to furnish a 
 beautiful illustration, on a minute scale, of the same prin- 
 ciple which gives a rounded form to the surface of the 
 sea. In one case, cohesion, by drawing toward a common 
 centre, forms the minute globule of dew upon the blade 
 of grass ; in the other, gravitation, acting in like manner, 
 but at vast distances, gives the mighty rotundity to the 
 rolling waters of the ocean. 
 
 CAPILLARY ATTRACTION. 
 
 Capillary attraction is a species of cohesion ; it takes 
 place only between solids and liquids. It is this which 
 holds the moisture on the surface of a wet body, and which 
 prevents the water from running instantly out of a wet 
 cloth or sponge. By touching the lower extremity of a 
 lump of sugar to the surface of water in a vessel, capillary 
 attraction will cause the water to rise among its granules 
 and moisten the whole lump. It may be very distinctly 
 shown by placing the end of a fine glass tube into water; 
 the water will rise in it above the level of the surrounding 
 surface. If the bore of the tube be the twelfth of an inch 
 
32 
 
 MECHANICS. 
 
 in diameter (a, fig. 15,) it will rise a quarter of an inch ; 
 if but the twenty-fifth of an inch in bore, as b, it will rise 
 half an inch ; but if only a fiftieth of an inch, the water 
 will rise an inch. This ascent of the liquid is caused by 
 the attraction of the inner surface of the tube, until the 
 weight of the column becomes equal to the force of the 
 attraction. Capillary attraction may be also exhibited by 
 
 Fig. 16 
 
 Capillary attraction in tubes. 
 
 Capillary attraction between two panes of 
 glass. 
 
 two small plates of glass, placed with their edges in wa- 
 ter, in contact on one side, and a little open at the 
 other side, as in fig. 16. As the faces of the plates ap- 
 proach each other, the water rises higher, forming the 
 curve, a. 
 
 Capillary attraction performs many important offices 
 in nature. The moisture of the soil depends greatly upon 
 its action. If the soil is composed of coarse sand or grav- 
 el, the interstices are large, and, like the larger glass tube, 
 will not retain the rain which falls upon it. Such soils 
 are, therefore, easily worked in wet weather, but become 
 too dry in seasons of drought ; but when the texture is 
 finer, and especially if a due proportion of clay be mixed 
 with the sand, the interstices become exceedingly small, 
 and retain a full sufficiency of moisture. If, however, 
 there is too much clay, the soil is apt to become close and 
 compact, and the water can not enter until it is broken up 
 
EARTH A DESERT WITHOUT CAPILLARY ATTRACTION. 
 
 or pulverized. It is for this reason that subsoil plowing 
 becomes so eminently beneficial, by deepening the mellow 
 portion, and thus affording a larger reservoir, which acts 
 like a sponge in holding the excess of falling rains, until 
 wanted in the dry season. For the same reason, a well- 
 cultivated soil is found to preserve its moisture much bet- 
 ter during the heat of summer than a hardened and neg- 
 lected surface. 
 
 If capillary attraction should cease to exist, the earth 
 would soon become a barren and uninhabitable waste. 
 The moisture of rains could not be retained by the parti- 
 cles of the soil, but would immediately sink 
 far down into the earth, leaving the surface 
 at all times as dry and unproductive as a 
 desert ; vegetation would cease ; brooks and 
 rivers would lose the gradual supplies which 
 the earth affords them through this influence, 
 and become dried up ; and all plants and all 
 animals die for want of drink and nourish- 
 ment. Thus the very existence of the whole 
 human race evidently depends on a law, ap- 
 parently insignificant to the unthinking, but 
 pointing the observing mind to a striking 
 proof of the creative design which planned all the works 
 of nature, and fitted them with the utmost exactness for 
 the life and comfort of man. 
 
 Apparatus ex- 
 plaining the 
 rising of sap. 
 
 ASCENT OF SAP. 
 
 The following interesting experiments serve to explain 
 the cause of the ascent of sap in plants and trees : 
 
 Take a small bladder, or bag made of any similar sub- 
 stance, and fasten it tightly on a tube open at both ends 
 (fig. 17) ; then fill them with alcohol up to the point C, 
 and immerse the bladder into a vessel of water. The al- 
 cohol will immediately rise slowly in the tube, and if not 
 
 o* 
 
34 MECHAXICG. 
 
 more than two or three feet high, will run over the top. 
 This is owing to the capillary attraction in the minute 
 pores of the bladder, drawing the water within it faster 
 than the same attraction draws the alcohol outward. One 
 liquid will thus intrude itself into another with great 
 force. A bladder filled with alcohol, with its neck tightly 
 tied, will soon burst if plunged under water. If a blad- 
 der is filled with gum-water, and then immersed as before, 
 the water will find its way within against a very heavy 
 pressure. 
 
 In this manner sap ascends through the minute tubes in 
 the body of trees. The sap is thickened like gum-water 
 when it reaches the leaves, and a fresh supply, therefore, 
 enters through the pores in the spongelets of the roots by 
 capillary attraction, and, rising through the stem, keeps 
 up a constant supply for the wants of the growing tree. 
 
 CENTRE OE GEAVITY. 
 
 The centre of gravity is that point in every hard sub- 
 stance or body, on every side of which the different parts 
 exactly balance each other. If the body be a globe or 
 Fig. 18. round ball, the centre of 
 
 gravity will be exactly at the 
 centre of the globe ; if it be 
 a rod of equal size, it will be 
 at the middle of the rod. If 
 a stone or any other sub- 
 stance rest on a point directly under the centre of gravity, 
 it will remain balanced on this point ; but if the point be 
 not under the centre of gravity, the stone will fall toward 
 the heaviest side. 
 
 Some curious experiments are performed by an ingenious 
 management of the centre of gravity. A light cylinder 
 of cork or pasteboard contains a concealed piece of lead, 
 g (fig. 18). The lead, being heavier than the rest, will 
 
CENTRE OF GRAVITY. EXPERIMENTS. 
 
 35 
 
 cause the cylinder to roll up an inclined plane, when 
 placed as shown by the lower figure on the preceding en- 
 
 graving, until it makes half a revolu- 
 tion and reaches the place of the up- 
 per figure, when it will remain sta- 
 tionary. If a curved body, as shown 
 in fig. 19, be loaded heavily at its 
 ends, it will rest on the stand, and 
 present a singular appearance by not 
 falling, the centre of gravity lying 
 between the two heavy portions on 
 the end of the stand. A light stick 
 of some length may be made to stand 
 on the end of the finger, by sticking 
 in two penknives, so as to bring the 
 centre of gravity as low as the 
 
 Fig. 19. 
 
 Body singularly balanced by 
 lead knobs. 
 
 finger-end (fig. 20). 
 
 If any body, of whatever shape, be suspended by a 
 
 hook or loop at its top, it will 
 necessarily hang so that the 
 centre of gravity shall be di- 
 rectly under the hook. In this 
 way the centre in any substance, 
 no matter how irregular its shape 
 may be, is ascertained. Sup- 
 pose, for instance, we have the 
 irregular plate or board shown 
 in the annexed Fig. 21. 
 
 figure (fig. 21) : 
 first hang it by 
 the hook a, andtf^ 
 the centre of 
 gravity will be 
 in 
 
 the dotted line a b. Then hang it by the hook c, and it 
 will be somewhere in the line c d. Now the point e, where 
 they cross each other, is the only point in both, conse- 
 
 Centre of gravity maintained by two 
 
 penknives. somewhere 
 
36 
 
 MECHANICS. 
 
 quently this is the centre sought. If the mass or body, 
 instead of being flat like a board, be shapeless like a stone 
 or lump of chalk, holes bored from different suspending 
 points directly downward will all cross each other exactly 
 at the centre of gravity. 
 
 LINE OF DIRECTION. 
 
 Fig. 22. 
 
 Fig. 23. 
 
 Centre of gravity on level and inclined 
 roads. 
 
 An imaginary line from the centre of gravity perpendic- 
 ularly downward to where the body rests is called the 
 line of direction. 
 
 Now in any solid body whatever, whether it be a wall, 
 a stack of grain, or a loaded wagon, the line of direction 
 must fall within the base or part resting upon the ground, 
 
 or it will immediately be 
 thrown over by its own 
 weight. A heavily and even- 
 ly loaded wagon on a level 
 road will be perfectly safe, be- 
 cause the line of direction falls 
 equally between the wheels, 
 as shown in fig. 22, by the 
 dotted line, c, being the centre. But if it pass a steep side- 
 hill road, throwing this line outside the wheels, as in fig. 23, 
 it must be instantly overturned. If, however, instead of 
 the high load represented in the figure, it be some very 
 heavy material, as brick or sand, so as not to be higher 
 than the square box, the centre will be much lower down, 
 or at 5, and thus, the line falling within the wheels, the 
 load will be safe from upsetting, unless the upper wheel 
 pass over a stone, or the lower wheel sink into a rut. 
 The centre of gravity of a large load may be nearly ascer- 
 tained by measuring with a rod ; and it may sometimes 
 happen that by measuring the sideling slope of a road, all 
 of which may be done in a few minutes, a teamster may 
 save himself from a comfortless upsetting, and perhaps 
 
CENTEE OP GEAVITY. LOADING WAGONS. 
 
 37 
 
 Fig. 24 
 
 heavy loss. Again, a load may be temporarily placed so 
 much toward one side, while passing a sideling road, as 
 to throw the line of direction considerably more up hill 
 than usual, and save the load, which may be adjusted 
 again as soon as the dangerous point is passed. This 
 principle also shows the reason why it is safer to place only 
 light bundles of merchandise on the top of a stage-coach, 
 while all heavier articles are to be down near the wheels ; 
 and why a sleigh will be less likely to upset in a snow- 
 drift, if all the passengers will sit or lie on the bottom. 
 When it becomes necessary 
 to build very large loads 
 of hay, straw, wool, or 
 other light substances, the 
 "reach," or the long con- 
 necting-bar of the wagon, 
 must be made longer, so as 
 
 tO increase the length of the Centre of gravity of an evenand one-sided 
 
 load ; for, by doubling the 
 
 length, two tons may be piled upon the wagon with as 
 
 much security from upsetting as one ton only on a short 
 
 wagon. 
 
 Where, however, a high load can not be avoided, great 
 care must be taken to have it evenly placed. If, for in- 
 stance, the load of hay represented by fig. 24 be skillfully 
 built, the line of direction will fall equally distant within 
 each wheel ; but a slight misplacement, as in fig. 25, will 
 so alter this line as to render it dangerous to drive except 
 on a very even road. 
 
 Thus every one who drives a wagon should understand 
 the laws of nature sufficiently to know how to arrange 
 the load he carries. It is true that experience and good 
 judgment alone will be sufficient in many cases; but no 
 person can fail to judge better, with the reasons clearly, 
 accurately, distinctly before his eyes, than by loose con- 
 jecture and random guessing. 
 
38 
 
 MECHANICS. 
 
 Zi. 
 
 Every farmer who erects a wall or building, every team- 
 ster who drives a heavy load, or even he who only carries a 
 heavy weight upon his shoulder, may learn something use- 
 ful by understanding the laws of gravity. 
 
 It is familiar to every one, that a body resting upon a 
 broad base is more difficult to upset than when the base 
 is narrow. For instance, the square 
 block (fig. 26) is less easily thrown 
 over than the tall and narrow block 
 of equal weight, because, in turning 
 the square block over its lower edge, 
 the centre of gravity must be lifted 
 up considerably in the curve shown 
 by the dotted line c y but with a tall, 
 narrow block, this curve being almost 
 on a level, very little lifting is re- 
 quired. Hence the reason that a high load on a wagon is 
 so much more easily overturned than a low one. 
 
 Of all forms, a pyramid stands the most firmly on its 
 base. The centre of gravity, c (fig. 26), being so near the 
 broad bottom, it must be elevated in a very steep curve 
 to throw the line of direction beyond the base. For this 
 reason, a stone wall, or the dam for a stream, will stand 
 better when broad at bottom and tapering to a narrow top 
 than if of equal thickness throughout. 
 
 When a globe or round ball is placed upon a smooth 
 floor, it rests on a single point. If the Fig. 27. 
 
 floor be level, the line of direction will 
 fall exactly at this resting-point (fig. 
 27). To move the ball, the centre will 
 move precisely on a level, without be- 
 ing raised at all. This is the reason 
 that a ball, a cylinder, or a wheel is rolled forward so 
 much more easily than a flat-sided or irregular body. In 
 all these cases, the line of direction, although constantly 
 
CENTRE OF GRAVITY. — EXAMPLES. 
 
 39 
 
 changing its place, still continues to fall on the very point 
 on wnich the round body rests. 
 
 But if the level floor is exchanged for a slope or inclin- 
 ed plane (fig. 28), the line of direc- Fig 28. 
 tion no longer falls at the touchinsr- 
 
 poi-nt, but on the side from it down- 
 
 ward ; the ball will therefore, by its 
 mere weight, commence rolling, and 
 continue to do so until it reaches the 
 bottom of the slope. 
 
 Wheel-carriages owe their comparative ease of draught 
 to the fact that the centre of gravity in the load is moved 
 forward by the rolling of the wheels, on a level, or paral- 
 lel with the surface of the road, just in the same way that 
 the round ball rolls so easily. Each wheel supporting its 
 part of the load at the hub, the same rule applies to each 
 as to a ball or cylinder alone. Hence, on a level road, the 
 line of direction falls precisely where the wheels rest on 
 the ground, but if the road ascend or descend, it falls else- 
 where ; this explains the reason why it will run by its own 
 weight down a slope. 
 
 Whenever a stone or other obstruction occurs in a road, 
 
 it becomes requisite to raise the 
 
 centre by the force of the team 
 
 and by means of oblique motion, 
 
 so as to throw the wheel over it, 
 
 as shown by fig. 
 
 29. One of the 
 
 reasons thus. 
 
 becomes very 
 
 plain why a 
 
 laro;e wheel will 
 
 Fig. 29. 
 
 run with more ease on a rough road than a smaller one ; 
 the larger one mounting any stone or obstruction without 
 lifting: the load so much out of a level or direct line, as 
 shown by the dotted lines in the annexed figures, (figs. 29 
 
40 
 
 MECHANICS. 
 
 A firmly- set fruit-ladder 
 
 A dangerous- 
 ly-set fruit- 
 ladder. 
 
 and 30). Another reason is, the large wheel does not 
 sink into the smaller cavities in the road. 
 
 A self-supporting fruit-ladder (fig. 31) (the centre of 
 gravity, when in use, being at or near the top) must have 
 
 its legs more widely 
 spread, to be secure from 
 falling, than if the centre 
 were lower down. Hence 
 such a position, as in fig. 
 32, would be unsafe. 
 
 The support of the 
 human body, in standing 
 and walking, exhibits 
 some interesting exam- 
 ples in relation to this 
 subject. A child can not learn to walk until he acquires 
 skill enough to keep his feet always in the line of direc- 
 tion. When he fails to do this, he topples over toward 
 the side where the line falls outside his feet. A man stand- 
 ing with his heels touching the wash-board of a room can 
 not possibly stoop over without falling, because, when he 
 bends, the line of direction falls forward 
 of his toes, the wall against which he 
 stands preventing the movement of his 
 body backward to preserve the balance. 
 
 In walking, the centre rises and falls 
 slightly at each step, as shown by the 
 waved line in fig. 33. If it were not 
 for the bending of the knee-joints, this 
 exercise would be much more laborious, 
 as it would then become needful to 
 throw the centre into an upward curve at every step. 
 For this reason, a wooden leg is more imperfect than the 
 natural one (fig. 34). Hence the reason why walking on 
 crutches is laborious and fatiguing, because at every on- 
 
 Fig. 33. 
 
 Fiff. 34. 
 
CENTRE OF GRAVITY. — EXAMPLES. 
 
 41 
 
 Fig. 35. 
 
 Fie-. 36. 
 
 ward step the body must be thrown upward in a curve, 
 like a wagon mounting repeated obstructions. 
 
 When a load is carried on the shoulder, it should be so 
 placed that the line of direction may pass directly through 
 
 the shoulder or back down to the 
 feet, fig. 35. An unskillful person 
 will sometimes place a bag of grain 
 as shown in fio\ 36. The line falling: 
 outside his feet, he is compelled to 
 draw downward with great force on 
 the other end of the bag. A man who 
 carries a heavy pole on his shoulder should see that the 
 centre is directly over his slioulder, otherwise he will be 
 compelled to bear down upon the lighter end, and thus 
 add in an equal degree to the weight upon his body. 
 
 If an elliptical or oval body, fig. 37, rest upon its side 
 a, rolling it in either direction elevates Fig. 37. 
 
 the centre, c, because it is nearest the 
 side on which the body rests. If, 
 when raised, it be suffered to fall, its 
 momentum carries it beyond the 
 point of rest, and thus it continues 
 rocking until the force is spent. The 
 course of the centre during these mo- 
 tions is shown by the curved dotted 
 line, c. If it be placed upon end, as in fig. 38, then any 
 motion toward either side brings the centre of gravity 
 
 nearer the touching-point, that is, 
 causes it to descend, and the body 
 consequently falls over on its side. 
 This may be easily illustrated with 
 an egg, which will lie at rest upon its 
 side, but falls when set on either end. 
 The rockers of chairs, cradles, 
 and cribs, are formed on the princi- 
 If so made that the centre of gravity 
 
 Fig. 38. 
 
 pie just explained. 
 
42 MECHANICS. 
 
 of the chair or cradle is nearer the middle of the rocker 
 
 than to the ends, the rocking motion will take place ; and 
 
 when the distance from the centre of gravity to the ends 
 
 _,. „ n w . ,„ of the rockers is but little greater 
 
 Fi£. 39. Fig. 40. > # to 
 
 than the distance to the middle, c, 
 as in fig. 39, the motion will be 
 slow and gentle ; but if this differ- 
 ence be greater, as in fig. 40, it will 
 be rapid. When the centre is high, 
 the rockers must have less curvature 
 than where it is low and near the floor. If the centre of 
 gravity be nearer the ends than to the middle, the chair 
 will immediately be overturned. This principle should 
 be well understood in the construction of every thing 
 which moves by rocking. 
 
 CHAPTER IV. 
 
 SIMPLE MACHINES, OR MECHANICAL POWERS. 
 ADVANTAGES OE MACHINES. 
 
 The moving forces which are applied to various useful 
 purposes commonly require some change in velocity, 
 direction, or mode of acting, before they accomplish the 
 desired end. For example, a running stream of water has 
 a motion in one direction only ; by the use of machinery, 
 we change this to an alternating motion, as in the saw of 
 the saw-mill, or to a rotatory or whirling motion, as in the 
 stones of a grist-mill. The direct or straightforward 
 power of a yoke of oxen is made, by the employment of 
 the plow, to produce a side-motion to the sod, as well as 
 to turn it through half a circle. The thrashing-machine 
 
. 
 
 SIMPLE MACHINES, OR MECHANICAL POWERS. 43 
 
 converts the slowly-acting pace of horses to the swift hum 
 of the spiked cylinder. 
 
 Any instrument used for thus changing or modifying 
 motion is called a machine, whether it be simple or com- 
 plex in its structure. Thus even a crow-bar, used in lifting 
 stones from the earth, by diminishing the motion given by 
 the hand and increasing its power, may be strictly termed 
 a machine; while a harrow, which neither alters the 
 course nor changes the velocity of the force applied, may 
 with more propriety be regarded as simply an implement 
 or tool. In common language, however, these distinctions 
 are not accurately observed, and a machine is usually con- 
 sidered to be any instrument consisting of different mov- 
 ing parts. 
 
 All machines, however complex, may be resolved into 
 two simple parts, or powers. These are, 
 
 1. The Lever ; 
 
 2. The Inclined Plane. 
 
 The wheel and axle, and the pulley are modified ap- 
 plications of the lever ; and the wedge and the screw of 
 the inclined plane, as will be shown on the following 
 pages. These six are usually termed the mechanical 
 powers. As they really do not possess any power in 
 themselves, but only regulate power, the term " simple 
 machines " may be regarded as most correct. 
 
 THE LAW OF VIRTUAL VELOCITIES. 
 
 Before proceeding to the simple machines, it may be 
 well to explain a very important truth, which should be 
 considered as lying at the foundation of all mechanical 
 philosophy, and which renders plain and simple many things 
 which would otherwise seem strange or contradictory. 
 This is, that the force required to lift any given body is 
 always in proportion to the weight of that body, taken 
 
44 MECHANICS. 
 
 together with the height to be raised. For instance, it 
 requires twice the force to raise two pounds as to raise 
 one pound, three times the force to raise three pounds, 
 and so forth. Also, twice as great a force is needed to 
 elevate any weight two feet as one foot, or three times as 
 great for three feet, and so on. Again, combining these 
 together, four times as great a force is required to raise 
 two pounds to a height of two feet as to raise one pound 
 only one foot ; eight times as great for four feet, and so 
 on. This holds true, no matter by what kind, of ma- 
 chinery it is accomplished. Now this may all seem very 
 simple, but it serves to explain many difficult questions in 
 relation to the real power possessed by all machines. 
 
 Take another example. Suppose that one wishes to 
 raise a weight of 1000 pounds to a height of one foot. If 
 his strength is equal to only 100 pounds, the weight 
 would be ten times too heavy for him. He might, there- 
 fore, divide it into ten equal parts of 100 pounds each. 
 Raising each part separately the required height of one 
 foot would be the same as raising one of them ten feet 
 high. The weight is lessened ten times, but the distance 
 is increased ten times. But there are some bodies, as, for 
 example, blocks of stone or sticks of timber, which can not 
 well be divided into parts in actual practice. He there- 
 fore resorts to a machine or mechanical power, through 
 which the same result is accomplished by raising the 
 whole weight in one mass with his single strength ; but in 
 this case as well as the other, the moving force which he 
 applies must pass through ten times the space of the 
 weight. We arrive, therefore, at the general rule, that the 
 distance moved by the weight is as much less than that 
 moved by the power as the power is less than the weight. 
 This rule is termed by some writers the " rule of virtual 
 velocities" virtual meaning not apparent or actual, but 
 according to the real effect, because the increase in 
 the velocity of the power makes up for increase in the size 
 
THE LEVEE. 45 
 
 of weight. This rule will be better understood after con- 
 sidering its application to the different simple machines. 
 
 The simplest of all machines is the lever. It consists of 
 a rod or bar, one end resting upon a prop or fulcrum, F 
 (fig. 41), near which is the weight, W, moved by the 
 hand at P. The stone may weigh 1000 pounds; yet, if it 
 is ten times as near the fulcrum as the man's hand is, a 
 force of 100 pounds will lift it ; but it will be moved only 
 a tenth part as high as the hand has been moved, as shown 
 
 Fifr41. 
 
 Lever of the second kind. 
 
 by the dotted lines. By placing the stone still nearer the 
 fulcrum, still less will be the power required to raise it, 
 but then the distance elevated would be also still less. By 
 sufficiently increasing the disproportion between the two 
 parts of the lever, the strength of a child merely might 
 be made to move more than many horses could draw. 
 
 These performances of the lever often excite astonish- 
 ment at what appears to be out of the common course of 
 things ; yet, when examined by the principles of mechan- 
 ics, instead of appearing matters of astonishment, they are 
 found to be only the natural and necessary results of the 
 laws of force. In the case of the lever just described, it is 
 often incorrectly supposed that the power itself sustains 
 the weight. But this is not the case ; nearly the whole 
 of it rests upon the fulcrum. We often see proofs of this 
 error in common practice, where fulcrums or props entirely 
 insufficient to uphold the enormous weight to be raised 
 are attempted to. be used. If the weight, for instance, be 
 ten times as near the fulcrum as to the power, then nine- 
 tenths of the weight rests upon the fulcrum, and the re- 
 
ierer of tlie first kind. 
 
 4Q MECHANICS. 
 
 maining tenth only is sustained by the lifting power. 
 The lever only allows the power to expend itself through 
 a longer distance, and thus, by concentrating itself at the 
 weight, to elevate the latter through the shorter distance, 
 according to the rule of virtual velocities already ex- 
 plained. 
 
 The fulcrum may be placed between the weight and the 
 Fig. 42. power, as in fig. 42, 
 
 or the power may be 
 placed between the 
 fulcrum and the 
 weight, as in fig. 43, 
 the same principle of virtual velocities applying in all cases. 
 Where the fulcrum is between the power and the 
 weight, as in fig. 42, it is called a lever of the first hind. 
 Where the weight is between the fulcrum and the 
 power, as in fig. 41, it constitutes a lever of the second 
 Icind. 
 
 Where the power is between the fulcrum and the 
 weight, as in fig. 43, it is termed a lever of the third 
 kind. 
 
 1. Many examples occur in practice of levers of the first 
 kind. A crow-bar, used to raise stones from the earth, is 
 an instance of this sort ; 
 so is a handspike of 
 any kind used in the 
 same way. A hammer 
 
 n ■, ., Lexer of the third kind. 
 
 tor drawing a nail 
 
 operates as a lever of the first kind, the heel being the ful- 
 crum, the nail the weight, and the hand the power; the 
 distance through which the handle passes being several 
 times greater than that of the claws, the force exerted on 
 the nail is increased in like proportion. A pair of scissors 
 consists of two levers, the rivet being the fulcrum ; and in 
 using them, as every one has observed, a greater cutting 
 force is exerted near the rivets than toward the points. 
 
THE LEVER. EXAMPLES. 47 
 
 This is owing to the power being expended through a 
 greater distance near the points, according to the rule al- 
 ready explained. Pincers, nippers, and other similar in- 
 struments are also double levers of the first kind. 
 
 A common steelyard is another example, the sliding 
 weight becoming gradually more effective as it is moved 
 further from the fulcrum or hook supporting the instru- 
 ment. The brake or handle of a pump is a lever of this 
 class, the pump-rod and piston being the weight. 
 
 The common balance is still another, the two arms being 
 exactly equal, so that one weight will always balance the 
 Pig. 44. other, and on this its usefulness 
 
 and accuracy entirely depend. 
 The most sensitive balances have 
 light beams with long arms, and 
 the turning-point of hardened 
 steel or agate, in the form of a 
 faiiiiiiiiiiiiiniiiiiiiwii)iuiimiriiiiii;iimiiiiii:iii!iii.iiii;iiimiii,wi;iiiiuiiii ! iMA thin wedge, on which the balance 
 turns almost without friction. Small balances have been 
 so skillfully constructed as to turn with one-thousandth 
 part of a grain. 
 
 2. Levers of the second kind are less numerous, but not 
 uncommon. A handspike used for rolling a log is an ex- 
 ample. A wheel-barrow is a lever of the second kind, the 
 fulcrum being the point where the wheel rests on the 
 ground, and the weight the centre of gravity of the load. 
 Hence, less exertion of strength is required in the arm 
 when the load is placed near the wheel, except where the 
 ground is soft or muddy, when it is found advantageous 
 to place the load so that the arm shall sustain a consider- 
 able portion, to prevent the wheel sinking into the soil. 
 A two-wheeled cart is a similar example ; and, for the same 
 reason, when the ground is soft, the load should be placed 
 forward toward the horse or oxen ; on the other hand, on 
 a smooth and hard, or on a plank road, the load should be 
 
48 
 
 MECHANICS. 
 
 more nearly balanced. An observance of this rule would 
 often save a great deal of needless waste of strength. 
 
 A sack-barrow, used in barns and mills for conveying 
 
 heavy bags of grain from one part of the floor to another, 
 
 Fig. 45. and in warehouses 
 
 for boxes, is a lever 
 nearly intermediate 
 between the first and 
 second kind, the 
 weight usually rest- 
 ing very nearly over 
 the fulcrum or 
 wheels. When the 
 bag of grain is 
 thrown forward of 
 the wheels, it be- 
 comes a lever of the 
 first kind ; when 
 back of the wheels, 
 it is a lever of the 
 second kind. As it 
 is used only on hard 
 and smooth floors, 
 and not, like the wheel-barrow, on soft earth, the more 
 nearly the load is placed directly over the wheels, the 
 more easily they will run. 
 
 3. In a lever of the third kind, the weight being further 
 from the fulcrum than the power, it is only used where 
 great power is of secondary importance when com- 
 pared with rapidity and dispatch. A hand-hoe is of this 
 class, the left hand acting as the fulcrum, the right hand 
 as the power, and the resistance overcome by the blade 
 of the hoe as the weight. A hand-rake is similar, as well 
 as a fork used for pitching hay. Tongs are double levers 
 of this kind, as also the shears used in shearing sheep. 
 The limbs of animals, generally, are levers of the third 
 
 Sack-bcwow. 
 
ESTIMATING THE POWEB OF LEVERS. 49 
 
 kind. The joint of the bone is the fulcrum; the strong 
 muscle or tendon attached to the bone near the joint is 
 the power; and the weight of the limb, with whatever re- 
 sistance it overcomes, is the weight. A great advantage 
 results from this contrivance, because a slight contraction 
 of the muscle gives a swift motion to the limb, so import- 
 ant in walking and running, and in the use of the arms. 
 
 ESTIMATING THE POWER OF LEVERS. 
 
 The power of any lever is easily calculated by measuring 
 
 the length of its two arms, that is, the two parts into 
 
 Fig. 46. which it is divided by 
 
 ,.&h the weisrht, fulcrum, 
 
 « v^ ; - ■ ■-■ - --- ■ •- ■ - . rg i TTi j-;^ -9^'— ~^ *f and power. In a 
 
 w\ F lever of the first kind 
 
 :--■:'''''' if the weight and 
 
 Lever of the first kind. power be equally dis- 
 
 tant from the fulcrum, they will move through equal dis- 
 tances, and nothing will be gained ; that is, a power of 
 100 pounds will lift a weight of 100 pounds only. If the 
 power be twice as far as the weight, its force will be 
 doubled; if three times, it will be tripled; and so forth. 
 In a lever of the second kind, if the weight be equidistant 
 between the fulcrum Fig. 47. 
 
 and power, the power c p-- : --r ; --__ 
 will move through ! ; ~~~~~~~~ r -~-- rr -._ r\ 
 
 twice the distance of ■ j ___j!L rgfe^^— , 
 
 the weight, and the m^ 
 
 n. . , , Lever of the second kind. 
 
 power 01 the instru- 
 ment will therefore be doubled ; if twice as far, it will be 
 tripled, and so on, as shown in the annexed figures. The 
 same mode of reasoning will explain precisely to what 
 extent the force is diminished in levers of the third kind. 
 
 These rules will show in what manner a load borne on 
 a pole is to be placed between two persons carrying it, 
 3 
 
50 
 
 MECHANICS. 
 
 If equidistant between them, each will sustain a like por- 
 tion. If the load be twice as near to one as to the other, 
 the shorter end will receive double the weight of the 
 
 longer. 
 
 For the same reason, 
 
 Fig. 48, 
 
 when three horses are 
 worked abreast, the two 
 horses placed together 
 should have only half 
 the length of arm of the 
 main w r hiffle-tree as the 
 single horse, fig. 48. 
 The farmer who has a 
 team of two horses un- 
 like in strength, may 
 thus easily know how to 
 adjust the arms of the 
 whiffle-tree so as to correspond with the strength of each. 
 If, for instance, one of the horses possesses a strength as 
 much greater than the other as four is to three, then the 
 weaker horse should be attached to the arm of the whiffle- 
 tree made as much longer than the other arm as four is 
 to three. 
 
 In all the preceding estimates, the influence of the 
 weight of the lever has not been taken into consideration. 
 In a lever of the first kind, if the thickness of the two 
 arms be so adjusted that it will remain balanced on the 
 fulcrum, its weight 
 will have no other 
 efiect than to in- 
 crease the pressure 
 on the fulcrum ; but 
 if it be of equal 
 size throughout, its longer arm, being the heavier, w T ill 
 add to its power. The amount thus added will be equal 
 to the excess in the weight of this arm, applied so far 
 along as the centre of gravity of this excess. If, for ex- 
 ample, a piece of scantling twelve feet long, a b, fig. 49, 
 
 mv 
 
COMBINATION OF LEVEES. 51 
 
 be used as a lever to lift the corner of a building, then 
 the two portions, a c, e d, will mutually balance each 
 other. If these be each a foot in length, the weight of 
 ten feet will be left to bear down the lever. The centre 
 of gravity of this portion will be at e, six feet from the 
 fulcrum, and it will consequently exert a force under the 
 building equal to six times its own weight, If the scant- 
 ling weigh five pounds to the foot, or fifty pounds for the 
 excess, this force will be equal to three hundred pounds. 
 
 In the lever of the second kind, its weight operates 
 'against the moving power. If it be of equal size through- 
 out, this will be equal to just one-half the weight of the 
 lever, the other half being supported by the fulcrum. 
 
 With the lever of the third kind, the rule applied to the 
 first must be exactly reversed. 
 
 COMBINATION OF LEVERS. 
 
 A great power may be attained without the inconven- 
 ience of resorting to a very long lever, by means of a com- 
 bination of levers. In fig. 
 50, the small weight P, act- 
 
 iA^ mg as a moving power, ex- 
 erts a three-fold force on the 
 next lever ; this, in its turn, acts in the same degree on the 
 third, which again increases the power three times. Con- 
 sequently, the moving power, P, acts upon the weight, 
 W, in a twenty-seven-fold degree, the former passing 
 through a space twenty-seven times as great as the latter. 
 A combination of levers like this is employed in self- 
 regulating stoves. It is in this case, however, used to 
 multiply instead of to diminish motion. The expansion 
 of a metallic rod by heat the hundredth part of an inch 
 acts on a set of iron levers, and the motion is increased, 
 by the time it reaches the draught-valve, to about one 
 hundred times. 
 
52 
 
 MECHANICS. 
 
 Fig. 51. 
 
 A more compact arrangement of compound levers is 
 shown in fig. 51, where the power, P, acts on the lever 
 
 A, exerting a force on the 
 lever B five times as great as 
 the power. B acts on the 
 lever C with a force increased 
 three times, and this, again, 
 on the weight, W, with a 
 four-fold force. Multiplying 
 5, 3, and 4 together, the prod- 
 uct is 60 ; hence a force of 
 one pound "at P will support 
 60 pounds at W. By gradu- 
 ating (or marking into 
 Itjwj ^ notches) the lever C, so that 
 
 Compound levers. the distance is measured as 
 
 the weight is moved along it, a compact and powerful 
 steelyard for weighing is formed. 
 
 WEIGHING MACHINE. 
 
 A valuable combination of levers is made in the con- 
 struction of the weighing machine, used for weighing cat- 
 tle, wagons loaded with hay, and other heavy articles. 
 
 Fisr. 52. 
 
 Weighing Machine. 
 
 The wagon rests on the platform A (fig. 52,) and this 
 platform rests on two levers at W, W, which presses their 
 other ends both on a central point, and this again bears on 
 
THE WEIGHING MACHINE. 
 
 53 
 
 the lever D, the other end of which is connected by means 
 
 of an upright rod with the steelyard at F. 
 
 There are two important points gained in this combina- 
 Fig. 53. tion. In the first place, the 
 
 levers multiply the power so 
 much that a few pounds' 
 weight will balance a heavy 
 load of hay weighing a ton 
 or more ; and, in the next, 
 the load resting on both the 
 levers, communicates the 
 same force of weight to the 
 central point, from whatever 
 part of the platform it hap- 
 pens to stand on : for if it 
 presses hardest on one lever, 
 Portable Platform Scale. it bears lighter, at a cor- 
 
 responding rate, on the other. In practice, there are 
 
 Fis. 54. 
 
 Large Platform Scale. 
 
 always two pairs, or four levers, which proceed from each 
 
54 
 
 MECHANICS. 
 
 Fig. 55. 
 
 corner of the platform, and rest on one point at the centre. 
 We have taken the two only, to simplify the explanation. 
 A powerful stump-extracting machine, allowing a suc- 
 cession of efforts in the use of the lever, is exhibited by- 
 fig. 55. The lever, «, should be a strong stick of timber, 
 furnished with three massive iron hooks, secured by bolts 
 
 passing through, as 
 represented in the 
 figure. Small or 
 truck wheels are 
 placed at each end 
 of the lever, merely 
 for the purpose of 
 moving it easily over 
 the ground. The 
 stump, b, used as a 
 fulcrum, has the 
 chain passing round 
 near its base, while 
 another chain passes 
 over the top of the 
 stump, c, to be torn 
 out. A horse is at- 
 tached to the lever 
 
 Lever Stump Machine. at d, and, moving to 
 
 e, draws the other end of the lever backward, and loosens 
 the stump ; while in this position, another chain is made 
 to connect g to A, and the horse is turned about, and draws 
 the lever backward to i, which still further increases the 
 loosening ; a few repetitions of this alternating process 
 tear out the stump. Very strong chains are requisite for 
 this purpose. Large stumps may require an additional 
 horse or a yoke of oxen. Where the stumps are remote 
 from each other, iron rods with hooks may be used to 
 connect the chains. 
 
 The power which may be given to this and to all other 
 
A WILD THE0EY. 
 
 55 
 
 Fi" 56. 
 
 modes of using the lever, as we have already seen, depends 
 on the difference between the lengths of its two arms. A 
 yoke of oxen, drawing with a force of 500 pounds on the 
 long arm of a lever 25 feet long, will exert a force on the 
 short arm of six inches equal to 50 times 500 pounds, or 
 25,000 pounds, on the stumj). 
 
 It was after an examination of the great power which 
 may be given to the lever by increasing this difference 
 that Archimedes exultingly exclaimed, " Give me but a 
 fulcrum whereon to place my 
 lever, and. I will move the earth !" 
 Admitting the theoretical truth of 
 this exclamation, and supposing 
 there could be a lever which he 
 might have used for this purpose, 
 its practical impossibility may be 
 quickly understood by computing 
 the whole bulk of the globe ; for 
 such is its enormous size and cu- 
 bical contents, that Archimedes 
 must have moved forward his 
 lever with the strength of a hun- 
 dred pounds and the swiftness 
 of a cannon ball for eight hundred million years to have 
 moved the earth the thousandth part of an inch ! 
 
 WHEEL AND AXLE. 
 
 In treating of the lever, it was shown to be capable of 
 exerting a force through a small distance only. Hence, 
 if a heavy body were required to be elevated to any con- 
 siderable height, it would be necessary to accomplish it 
 by a succession of efforts. This inconvenience is removed 
 by a constant and unremitted action of the lever in the 
 form of the wheel and axle. 
 
 Let the weight, w (fig. 56,) be suspended by a cord 
 
56 
 
 MECHANICS. 
 
 from the end of the lever, a &, and a, wheel attached to 
 the lever, so that this cord may wind upon it as the 
 weight is elevated ; then let the power be applied at the 
 other end by means of a cord, and a larger wheel be at- 
 tached, so that this cord too may wind upon the larger 
 wheel. These two wheels (fastened together so as to 
 form one), as they are made to revolve on their axis, will 
 now constitute, in a manner, a succession of levers, acting 
 through an indefinite distance according to the length of 
 the cords. The levers here successively acting are of the 
 " first kind," and the axis of the wheel is the fulcrum. 
 This arrangement constitutes in substance the wheel and 
 axle ; and its power, like that of the simple lever, depends 
 on the comparative velocity of the weight and the moving 
 force. If, for example, the larger wheel is four times the 
 circumference of the smaller, a force of one hundred applied 
 to the outer cord will raise a weight of four hundred 
 pounds. 
 
 The annexed figure exhibits at one view the power ex- 
 erted through the 
 wheel and axle, where 
 a small weight of C 
 pounds wall wind up 
 (or balance) other 
 w r eights separately, 
 weighing 8, 12, or 24 
 pounds, as the differ- 
 ence increases between 
 the size of the wheel 
 and of the axle, ac- 
 cording to the rule of 
 virtual velocities already explained. 
 
 The thickness of the rope has not been taken into con- 
 sideration. This is very small when compared with the 
 diameter of the outer wheel, but often considerable when 
 compared with that of the inner. To be strictly accurate, 
 
 Fig. 57. 
 
 Wheel and axle, showing the heavier weight for 
 less motion. 
 
WHEEL AND AXLE. EXAMPLES. 57 
 
 therefore, the force must be considered as acting at the 
 centre of the rope ; hence the diameter of the rope must 
 be added to the diameter of the wheel. 
 
 There are various forms of the wheel and axle. In the 
 common windlass, motion is given to the axle by means of 
 a winch, which is a lever like the handle of a grindstone. 
 The windlass used in digging wells has usually four pro- 
 jecting levers or arms. The wheel used in steering a ves- 
 sel is furnished with pins in the circumference, to which 
 the hand is applied in turning it. In the capstan (for 
 weighing anchor) the axis is vertical, and horizontal levers 
 are applied around it, so that several men may work at 
 once. The power of all these forms is easily calculated 
 by the rule of virtual velocities — that is, that the velocity 
 with which the power moves is as many times greater 
 than the velocity of the weight, as the weight exceeds the 
 power. A simple and convenient rule for computing in 
 numbers the power of wheel-work is the following : Multi- 
 ply all the numbers together which express either the cir- 
 cumferences or diameters of the large wheels, and then 
 multiply together all the numbers which express the diam- 
 eters of the smaller wheels or pinions; divide the greater 
 number by the less, and the quotient will be the power 
 sought. 
 
 BAND AND COG WHEELS 
 
 Where great power is required, several wheels and 
 axles may be combined in a man- Fig. 59. 
 
 ner corresponding with that of the 
 compound system of levers already 
 explained. In this case the axis of 
 one wheel acts on the circumference 
 of the next, producing a continued 
 slower motion, and increasing the 
 power in a corresponding degree. Combined cog-wheels. 
 The wheels are made thus to act by means of cogs or teeth, 
 3* 
 
58 
 
 MECHANICS. 
 
 Fig. 60. 
 
 or of bands (fig. 59). In ordinary practice, however, com- 
 bined wheels are made use of to multiply motion instead 
 of to diminish it, familiar instances of which occur in the 
 grist-mill and thrashing machine. 
 
 In connecting a system of w T heels, the cord or strap 
 may be used where great force is not required, the friction 
 round the circumference being sufficient to prevent slip- 
 ping. Bands are chiefly useful where motion is to be 
 transmitted to a distance ; as, for example, from a horse- 
 power without a barn to a thrashing-machine within it. 
 
 Liability of sliding is some- 
 times useful, by preventing 
 the machinery from breaking 
 when a sudden obstruction 
 occurs. Where the force is 
 great, the necessary tension or 
 tightness of the cord produces 
 too great a friction at the 
 axle. In such cases, cogs or 
 teeth must be resorted to. 
 The term teeth is usually 
 applied when they are formed 
 of the same piece as the 
 wheel, as in the case of cast- 
 iron wheels. Cogs are teeth 
 formed separately and inserted into the wheel, as with 
 wooden wmeels. Pinions are the small wheels, or, more 
 properly, teeth set on axles. 
 
 Form of cogs— a, badly formed ; 
 b, proper form. 
 
 FORM OF TEETH OR COGS. 
 
 The form of the teeth has a great influence on the 
 amount of friction among wheel-work. Badly formed 
 teeth are represented by the wheel-work at a, in the an- 
 nexed figure, consisting of square projecting pins. When 
 these teeth first come into contact with each other, they 
 
FORM OF TEETH OR COGS, 
 
 59 
 
 Fig. 61. 
 
 act obliquely together, and thus a part of their force is lost, 
 and they continue scraping together with a large amount 
 of friction so long as they remain in contact. These 
 effects are avoided by giving to them the curved form, 
 represented by b. Here, instead of pressing each other 
 obliquely, they act at right angles, that is, not obliquely, 
 and instead of scraping, they roll over each other with 
 ease. These curves are as- 
 certained by mathemat- 
 ical calculation, which 
 can not be here given ; 
 it may be enough to state 
 that they should be so 
 formed that the points 
 in contact shall always 
 work at right angles to 
 each other. For ordi- 
 nary practical purposes 
 as shown in the annexed 
 
 y-~- 
 
 Mode of giving the best form to cogs. 
 
 however, they may be made 
 tne annexed figure (fig. 61), by striking 
 circles whose diameters shall embrace just three teeth. 
 The points of the teeth thus formed are removed, leaving 
 a blunt extremity, according to the figure. 
 
 There are a few other rules that should always be ob- 
 served in constructing wheel-work, in order that the 
 wheels may run easily together, without jerking o? rat- 
 tling, the most important of which are the following : 
 
 1. The teeth must be of uniform size and distance from 
 each other, through the whole circumference of the wheel. 
 
 2. Any tooth must begin to act at the same instant 
 that the preceding tooth ceases to touch its corresponding 
 tooth on the other wheel. 
 
 3. There must be sufficient space between the teeth not 
 only to admit those of the other wheel, but to allow a cer- 
 tain degree of play, which should be equal to at least one- 
 tenth of the thickness of the teeth. 
 
 4. The pinions should not be very small, unless the 
 
60 
 
 MECHANICS. 
 
 wheels they act on are quite large. In a pinion that has 
 only eight teeth, each tooth begins to act before it reaches 
 the line of the centres, and it is not disengaged as soon as 
 the next one begins to act. A pinion of ten teeth will 
 not operate perfectly if working in a wheel of less than 72 
 teeth. Pinions of less than six teeth should never be 
 used. 
 
 5. To give strength to the teeth of wheels, make the 
 wheels themselves thicker, which increases the breadth of 
 the teeth. 
 
 6. Wheel-work is often defective when not made of 
 uniform material, in consequence of the relative number 
 
 Fig. 62. of teeth working together not being such as 
 to equalize the wear of all alike. If the 
 number of teeth on a wheel is divided with- 
 out a remainder by the number of the pinion, 
 then the same teeth will repeatedly engage 
 each other, and they will often wear uneven- 
 ly. The number should be so arranged that 
 
 every tooth of the pinion may work in succession into the 
 
 teeth of the wheel. This is best effected by first taking a 
 
 number for the wheel that will be evenly 
 
 divided by the number on the pinion, and 
 
 then adding one more tooth to the wheel. 
 
 This will effect a continual change, so 
 
 that no two shall be engaged with each 
 
 other twice until all the rest have been 
 
 gone through with. This odd tooth is 
 
 called the hunting-cog. 
 
 Cog-wheels are most usually made 
 
 with the teeth on the outside or cir- 
 cumference of the wheel ; these are termed spur-icheels. 
 If the teeth are set on one side of the wheels, they are 
 
 termed crown-wheels. When they are made so as to work 
 
 together obliquely, they are called bev el-wheels, as in fig. 62. 
 Where the obliquity is small, the motion may be com- 
 
 Bevd-icheels. 
 
 Fig. 03. 
 
 Universal joint. 
 

 THE PULLET. 
 
 Gl 
 
 municated by means of the universal joint, as shown in 
 fig. 63. This is commonly used in the thrashing-machine, 
 where there is a slight change in the direction of motion 
 between the horse-power and the thrasher. 
 
 THE PULLEY. 
 
 Pulley doubling the 
 force. 
 
 fixed at one end pass round a movable 
 grooved wheel, and be grasped by the 
 hand at the other end : then, in lifting 
 any weight attached to the wheel, by 
 drawing up the cord, the hand will move 
 with twice the velocity of the weight. 
 It will, therefore, exert double the degree 
 
 Fie. 65. 
 
 of force. This operates 
 precisely as a succession of 
 levers of the second kind, 
 the fixed cord being the 
 fulcrum, and the cord drawn 
 up by the hand, the power. 
 It thus constitutes one of the simplest kinds 
 of the pulley, fig. 64. 
 
 The wheel is called a sheave; the term 
 pulley is applied to the block and sheave ; 
 and a combination of sheaves, blocks, and 
 ropes is called a tackle. 
 
 There are various combinations of single 
 pulleys for increasing power, the most com- 
 mon of which, and least liable to become 
 deranged by the cord being thrown off the 
 wheels, is shown in fig. 65. In this and in 
 all similarly constructed pulleys, the weight 
 is as many times greater than the power as 
 the number of cords which support the low r er block. If 
 there lie six cords, as in the figure, the weight will be six 
 limes the power. 
 
 Pulley of six-fold 
 power. 
 
62 
 
 MECHANICS. 
 
 Pulley with no increase of 
 power. 
 
 Where a cord is passed over a single fixed wheel, as in 
 
 fig. 66, or over two or more wheels, no power is gained, 
 
 Fig. 66 . the moving force being the same in 
 
 17 velocity as the weight. Such pulleys 
 
 are sometimes, however, of use by 
 
 altering the direction of the force. 
 
 The latter is applied with advantage 
 
 to unloading or pitching hay by 
 
 means of a horse-power, saving much 
 
 time and labor, as explained on a 
 
 future page. 
 
 Among the many applications of 
 the pulley, one is shown in the ac- 
 companying figure (fig. 67) rep- 
 resenting Packer's Stone Lifter, for 
 raising large boulders from the soil, 
 weighing from one to four and five 
 tons, and afterwards placing them in 
 Avails. It is also employed for tearing out small or partly 
 decayed stumps. 
 
 The usefulness of the pulley depends mainly upon its 
 lightness and port- Fig. gt. 
 
 able form, and the 
 facility with which 
 it may be made 
 to operate in al- 
 most any situation. 
 Hence it is much 
 used in building, 
 and is extensively 
 applied in the rig- 
 ging of ships. In Packer's Stone Lifter. 
 the computation of its power there is a large drawback, 
 not taken into account in the preceding calculation, which 
 materially lessens its advantage; this is the friction of 
 the wheels and blocks and the stiffness of the cordage. 
 
THE INCLINED PLANE. 63 
 
 which are often so great that two-thirds of the power 
 is lost. 
 
 THE INCLINED PLANE. 
 
 The inclined plane or slope possesses a power which is 
 estimated by the proportion which its length bears to the 
 height. If, for example, the plane be twice as long as the 
 perpendicular height, then in rolling the body a up the 
 inclined plane (fig. G8), it will move through twice the 
 distance required to lift it directly from b to c. Therefore 
 only one-half the strength else required need be exerted for 
 this purpose. The same reasoning Fi g . es. 
 
 will apply to any other proportion c 
 between the height and length ; 
 that is, the more gradual or less 
 steep the slope becomes, the greater J) 
 will be the advantage gained. A familiar example occurs 
 in lifting a loaded barrel into a wagon : the longer the 
 plank used in rolling it, the less is the exertion needed. 
 
 A body, in rolling freely down an inclined plane, acquires 
 the same velocity that it would attain if dropped perpen- 
 dicularly from a height equal to the perpendicular height 
 of the plane. Thus, if an inclined plane on a plank road 
 be 100 yards long and 16 feet high, a freely running 
 wagon, left to descend of its own accord, will move 32 
 feet per second by the time it reaches the bottom, that 
 being the velocity of a stone falling 16 feet. Or, a rail- 
 car on an inclined plane 145 feet high will attain a speed 
 of 96 feet per second, or more than 65 miles an hour, at 
 the foot of the plane, which is equal to the velocity of a 
 stone falling three seconds, or 145 feet. 
 
 ASCENT IN EOADS. - 
 
 All roads not perfectly level may be regarded as inclined 
 planes. By the application of the preceding rule, we 
 
64 MECHANICS. 
 
 may discover precisely how much strength is lost in draw- 
 ing heavy wagons up hill. If the load and wagon weigh 
 a ton, and the road rise one foot in height to every five 
 feet of distance, then the increased strength required to 
 draw the load will be one-fifth of its weight, or equal to 
 400 pounds. If it rise only one foot in twenty, then the 
 increase in power needed to ascend this plane will be only 
 100 pounds. The great importance of preserving, as 
 nearly as practicable, a perfect level is obvious. 
 
 There are many roads made in this country, rising over 
 and descending hills, which might be made nearly level by 
 deviating a little to the right or to the left. Suppose, for 
 example, that a road be required to connect the two points 
 
 Ffe. 69. 
 
 Smiles b 
 
 a and b (fig. 69), three miles apart, but separated by a 
 lofty hill midway between them, and one mile in diameter. 
 Passing half a mile on either side would entirely avoid 
 the hill, and the road thus curved would be only one 
 hundred and forty-eight yards, or one-twelfth of a mile 
 longer. The same steep hill is ascended perhaps fifty to 
 five hundred times a year by a hundred different farmers, 
 expending an amount of strength, in the aggregate, 
 sufficient to elevate ten thousand tons annually to this 
 height, as a calculation will at once show — more than 
 enough for all the increased expense of making the road 
 level. 
 
 It is interesting and important to examine how much 
 further it is expedient to carry a road through a circuitous 
 level course than over a hill. To ascertain this point, we 
 must take into view the resistance occasioned by the rough 
 surface or soft material of the road. Roads vary greatly 
 
THE RESISTANCE OF ROADS. 65 
 
 in this particular, but the following may be considered as 
 about a fair average. In drawing a ton weight (including 
 wagon) on freely running wheels, on a perfect level, the 
 strength exerted will be found about equal to the follow- 
 
 ing 
 
 On a hard, smooth plank road 40 pounds. 
 
 On a good Macadam road 60 " 
 
 On a common good Lard road 100 " 
 
 On a soft road about 200 " 
 
 Now let us compare this resistance to the resistance of 
 drawing up hill. First, for the plank road — forty pounds 
 is one-fiftieth of a ton ; therefore a rise of one foot in fifty 
 of length will increase the draught equal to the resistance 
 of the road. Hence the road might be increased fifty feet 
 in length to avoid an ascent of one foot ; or, at the same 
 rate, it might be increased a mile in length to avoid an 
 ascent of one hundred and five feet. But in this estimate 
 the increase in cost of making the longer road is not taken 
 into account. If making and keeping in repair be equal 
 to three hundred dollars yearly per mile, and one hundred 
 teams pass over it daily, at a cost for traveling of four 
 cents each per mile, being four dollars daily, or twelve 
 hundred dollars per annum, then the cost of making and 
 repair would be one quarter of the expense of traveling 
 over it. Therefore the mile should be diminished one 
 quarter in length to make these two sources of expense 
 counterbalance each other. Hence a road with this 
 amount of travel should, with a reference to public 
 accommodation, be made three-fourths of a mile longer 
 to avoid a hill of one hundred and five feet. This 
 estimate applies to, loaded teams only. For light car- 
 riages the advantages of the level road would not be so 
 great. One-half to five-eighths of a mile would, there- 
 fore, be a fair estimate for all kinds of traveling taken 
 together. 
 
66 MECHANICS. 
 
 The following table shows the rise in a mile of road for 
 different ascents : 
 
 For a rise of 1 foot in 10, the road ascends 528 feet per mile, 
 do. 1 do. 13, do. 406 do. 
 
 do. 
 
 1 
 
 do. 
 
 15, 
 
 do. 
 
 352 
 
 do. 
 
 do. 
 
 1 
 
 do. 
 
 20, 
 
 do. 
 
 204 
 
 do. 
 
 do. 
 
 1 
 
 do. 
 
 25, 
 
 do. 
 
 211 
 
 do. 
 
 do. 
 
 1 
 
 do. 
 
 30, 
 
 do. 
 
 176 
 
 do. 
 
 do. 
 
 1 
 
 do. 
 
 35, 
 
 do. 
 
 151 
 
 do. 
 
 do. 
 
 1 
 
 do. 
 
 40, 
 
 do. 
 
 132 
 
 do. 
 
 do. 
 
 1 
 
 do. 
 
 45, 
 
 do. 
 
 117 
 
 do. 
 
 do. 
 
 1 
 
 do. 
 
 50, 
 
 do. 
 
 106 
 
 do. 
 
 do. 
 
 1 
 
 do. 
 
 100, 
 
 do. 
 
 53 
 
 do. 
 
 do. 
 
 1 
 
 do. 
 
 125, 
 
 do. 
 
 42 
 
 do. 
 
 
 The same kind of reasoning applied to a common good 
 road will show that it will be profitable for the public to 
 travel about half that distance to avoid a hill of one 
 hundred and five feet. In this case the whole yearly- 
 cost of the road, including interest on the land, and the 
 cost of repairs, would not usually be more than a tenth 
 part of the same cost for plank, or would not exceed thirty 
 dollars. 
 
 On rail-roads, where the resistance is only about one- 
 fifth part of the resistance of plank roads, the dispropor- 
 tion between the draught on a level and up an ascent be- 
 comes many times greater. Thus, if a single engine move 
 three hundred and fifty tons on a level, then two engines 
 will be required for an ascent of only twenty feet per 
 mile, four engines for fifty feet per mile, and six engines 
 for eighty feet per mile. 
 
 Such estimates as these merit the attention of the 
 farmer in laying out his own private farm roads. It may 
 be worthy of considerable effort to avoid a hill of ten or 
 twenty feet, which must be passed over a hundred times 
 yearly with loads of manure, grain, hay, and wood. The 
 greatly increased resistance of soft materials, also, is too 
 rarely taken into account. A few loads of gravel, well 
 applied, would often prevent ten times the labor in plow- 
 

 FORM AND MATERIALS FOR ROADS. 67 
 
 ing through deep ruts, to say nothing of the breaking 
 of harness and wagons by the excessive exertions of the 
 team. 
 
 FORM AND MATERIALS FOR ROADS. 
 
 The depth of the mud in common roads is often un- 
 necessarily great, in consequence of heaping together 
 with the plow and scraj>er the soft top-soil for the raised 
 
 F\z. 70. 
 
 Scclio7i of badly forined road. 
 
 carriage-way. When heavy rains fall, this forms a deep 
 bed of mud, into which the wheels work their way, and 
 cause extreme labor to the team. A much better way is 
 to scrape off and cart away into the fields adjoining all 
 the soft, rich, upper surface, and then to form the harder 
 subsoil into a slightly rounded carriage-way, with a ditch 
 on each side. Such roads as this have a very hard and 
 firm foundation, and they have been found not to cut up 
 
 Fig. 71. 
 
 Section of loett-formed road. 
 
 into ruts, nor to form much mud, even in the wettest sea- 
 sons. On this hard foundation six inches of gravel will 
 endure longer and form a better surface than twelve 
 inches on a raised " turnpike" of soft soil and mud. 
 
 It frequently happens that the form of the surface in- 
 creases the quantity of mud in a road, by not allowing 
 the water to flow off freely. The earth is heaped up in a 
 high ridge, but having little slope on the top (fig. 70), 
 where the water lodges, and ruts are formed, the only dry 
 portions being on the brink of the ditches, where the 
 water can escape. Instead of this form, there should be a 
 gradual inclination from the centre to the ditches, as 
 shown in fi^. 71. This inclination should not exceed 1 
 
68 MECHANICS. 
 
 foot iii 20. On hill-sides the slope should all be toward 
 the higher ground, as in fig. 72. 
 
 Hard and durable roads are made on the plan of Telford. 
 Their foundation is rounded stones, placed upright, with 
 the smaller or sharper ends upward. The smaller stones 
 
 Fig. 72. 
 
 
 Section of road for hillsides. 
 
 are placed near the sides, and the larger at the centre, 
 thus giving to the road a convex form. The spaces 
 are then filled in with small broken stone, and the whole 
 covered with the same material or with gravel. The 
 pressure of wagons crowds it compactly between the 
 stones, and forms a very hard mass. 
 
 IMPORTANCE OP GOOD ROADS. 
 
 The principles of road-making should be better under- 
 stood by the community at large. Farmers are deeply 
 interested in good roads. Nearness to market, and facili- 
 ties for all other kinds of communication, are worth a 
 great deal, often materially affecting the price of land 
 and its products. The difference between traveling ten 
 miles through deep mud, at two miles per hour, with half 
 a load, and traveling ten miles over a fine road, at five 
 miles per hour, with a full load, should not be forgotten. 
 
 " In the absence of such facilities," says Gillespie, " the 
 richest productions of nature waste on the spot of their 
 growth. The luxuriant crops of our western prairies are 
 sometimes left to decay on the ground, because there are 
 no rapid and easy means of conveying them to market. 
 The rich mines in the northern part of the State of New 
 
GOOD AND BAD ROADS. G9 
 
 York are comparatively valueless, because the roads among 
 the mountains are so few and so bad, that the expense of 
 the transportation of the metal would exceed its value. 
 So, too, in Spain it has been known, after a succession of 
 abundant harvests, that the wheat has actually been 
 allowed to rot, because it would not repay the cost of 
 carriage." Again, " When the Spanish government re- 
 quired a supply of grain to be transferred from Old Castile 
 to Madrid, 30,000 horses and mules were necessary for the 
 transportation of four hundred and eighty tons of wheat. 
 Upon a broken-stone road of the best sort, one-hundredth 
 of that number could easily have done the work." He 
 further adds, in speaking of the improvements in roads 
 made by Marshal Wade, in the Scottish Highlands, " His 
 military road is said to have done more for the civilization 
 of the Highlands than the preceding efforts of all the 
 British monarchs. But the later roads, under the more 
 scientific direction of Telford, produced a change in the 
 state of the people which is probably unparalleled in the 
 history of any country for the same space of time. Large 
 crops of wheat now cover former wastes ; farmers' houses 
 and herds of cattle are now seen where was previously a 
 desert ; estates have increased seven-fold in value and 
 annual returns ; and the country has been advanced at 
 least one hundred years." 
 
 THE WEDGE. 
 
 The wedge is a double inclined plane, the power being- 
 applied at the back to urge it forward. It becomes more 
 and more powerful as it is made more acute ; but, on ac- 
 count of the enormous amount of friction, its exact power 
 can not be very accurately estimated. It is nearly always 
 urged by successive blows of a heavy body, the momentum 
 of which imparts to it great force. 
 
 All cutting and piercing instruments, as knives, scissors, 
 
70 
 
 MECHANICS. 
 
 chisels, pins, needles, and awls, are wedges. The degree 
 of acuteness must be varied according to circumstances ; 
 knives, for instance, which act merely by pressure, may be 
 made with a much sharper angle than axes, which strike 
 a severe blow. For cutting very hard substances, as iron, 
 the edge must be formed with a still more obtuse angle. 
 
 The utility of the wedge depends on the friction of its 
 surfaces. In driving an iron wedge into a frozen or icy 
 stick of wood, as every chopper has observed, the want 
 of sufficient friction causes it immediately to recoil, unless 
 it be previously heated in the fire. The efficacy of nails 
 depends entirely on the friction against their wedge-like 
 faces. 
 
 THE SCREW 
 
 The screw may be regarded as nothing more than an 
 Fig. 74 inclined plane winding round the surface of a 
 j^t___jiifen cylinder (fig. 74). This may be easily under- 
 stood by cutting a piece of paper in such a 
 form that its edge, a b (fig. 75), may represent 
 the inclined plane ; then, beginning at the wider 
 end, and wrapping it about the cylindrical piece 
 of wood, e, the upper edge of the paper will 
 represent the thread of the screw. 
 Although the friction attending the use of the screw is 
 
 considerable, and without it it would not retain its place, 
 
 yet the slope of its in- 
 clined thread being so 
 
 gradual, it possesses 
 
 great power. This power 
 
 is multijmed to a still 
 
 greater degree by the 
 
 lever which is usually employed to drive it, a (fig. 76). 
 
 If, for example, a screw be ten inches in circumference, 
 
 and its thread half an inch apart, it exerts a force twenty 
 
 Fig. 75. 
 
THE SCREW. 
 
 71 
 
 Fig. 76. 
 
 times as great as the moving power. If it be moved 
 by a lever twenty times as long as the diameter of the 
 screw, here is another increase of twenty 
 times in force. Multiplying 20 by 20 
 gives 400, the whole amount gained by 
 this combination, and by which a man 
 applying one hundred pounds in force 
 could exert a pressure equal to twenty 
 tons. About one-third or one-fourth of 
 this should, however, be deducted for 
 friction. 
 
 When the screw is combined with the 
 wheel and axle (fig. 77), it is capable of exerting great 
 power, which may be readily calculated by multiplying 
 the power of the screw and its lever into the power of 
 the wheel and axle. 
 
 Screw and lever 
 combined. 
 
 THE KNEE-JOINT POWER. 
 
 Fig. 77. 
 
 The knee-joint or toggle-joint is usually regarded as a com- 
 pound lever, and consists of two rods connected by a turn- 
 ing joint, as represented in fig. 78. The outer end of one of 
 
 the levers is fixed to 
 a solid beam, and the 
 other connected with 
 a movable block. 
 When the joint a is 
 forced in the direc- 
 tion indicated by the 
 arrow, it produces a 
 powerful pressure 
 upon the movable 
 block, which in- 
 creases as the lever approaches a straight line. This is 
 easily understood by the rule of virtual velocities, for the 
 force moves with a velocity many times greater than the 
 
 Screw, lever, and wheel 
 cornbiiwcl. 
 
 Knee-joint power. 
 
72 
 
 MECHANICS. 
 
 power given to the block, and this relative difference in- 
 creases as the joint is made straighter. 
 
 This power is made use of in the lever printing-press, 
 where the greatest force is given just as the pressure is 
 completed. Another example occurs in the Lever Wash- 
 ing-machine (fig. 79), which is worked by the alternating 
 motion of the handle, A, pressing a swinging board, per- 
 
 Fiff. 79. 
 
 Lever Washing-machine. 
 
 forated with holes, with great force against the clothes 
 next to one side of the water-box. Like the printing- 
 press, this machine exerts the greatest power just as the 
 motion of the lever is completed, and at the time it is 
 most needed. The same principle is exhibited in Kendall's 
 Cheese-press (fig. 80), where the lever and the wheel and 
 axle are combined with the two knee-joints, one on each 
 side of the press, drawing down a cross-beam upon the 
 cheese with a greatly multiplied power. 
 
 Dick's Cheese-press (fig. 83), operates on a similar 
 principle. Figs. 81-2 show the structure of its working 
 
LEVER WASHING-MACHINE. 
 
 Pig. 80. 
 
 73 
 
 Fig. 82. 
 
 KendalVs Cheese-press. 
 
 part, the dotted lines indicating the position of the lever, 
 which is inserted into a roller or axle, and, by turning, 
 drives the movable iron blocks asunder, and raises the 
 cheese against the broad screw-head above, as shown in 
 fig. 82. In fig. 81, the raised lever shows that the blocks 
 Tip-. 81. are at ^ rs<} near together, but are 
 crowded asunder as the lever is press- 
 ed downward. This cheese-press is 
 made of cast-iron, and has great 
 power; to try it, weights were in- 
 creased upon the lever, until the iron 
 frame broke with a force equal to six- 
 teen tons. 
 
 The power exerted by a rolling- 
 mill, where bars of iron are flattened 
 in their passage between two strong 
 rollers, is precisely like that of the knee-joint. The only 
 4 
 
•74 
 
 MECHANICS. 
 
 Fig. 83. 
 
 Dick's cast-iron Cheese-press. 
 
 difference is, that the rollers, which may be considered as a 
 constant succession of levers coming into play as they re- 
 volve, are both fixed, and consequently the bar has to yield 
 between them (fig. 84). The Fig. 84. 
 
 greatest power is exerted just 
 as the bar receives the last 
 pressure from the rollers. The 
 most powerful and rapidly- 
 working straw-cutters are those 
 which draw the straw or hay 
 between two rollers, one of 
 which is furnished with knives 
 set around it parallel with its 
 axis, and cutting on the other, which is covered with un- 
 tanned ox-hide (fig. 85). 
 
 Principle of the knee-joint in the 
 rolling-mill 
 
STRAW CUTTERS. 
 Fig. 85. 
 
 75 
 
 Hide Boiler Straw Cutter. 
 
 CHAPTER Y. 
 
 APPLICATION OF MECHANICAL PRINCIPLES IN THE 
 
 STRUCTUPvE OF SIMPLE IMPLEMENTS AND 
 
 PARTS OF MACHINES. 
 
 In contriving the more difficult and complex machines, 
 the principles of mechanics must be closely studied, to 
 give every part just that degree of strength required, and 
 to render their operation as perfect as possible. But in 
 making the more common and simple implements of the 
 farmer, mere guess-work too often becomes the only guide. 
 Yet it is highly useful to apply scientific knowledge even 
 in the shaping of a hoe handle or a plow-beam. 
 
 The simplest tool, if constantly used, should be formed 
 with a view to the best application of strength. The 
 laborer who makes with a common hoe two thousand 
 
76 MECHANICS. 
 
 strokes an hour, should not wield a needless ounce. If 
 any part is heavier than necessary, even "to the amount of 
 half an ounce only, he must repeatedly and continually 
 lift this half ounce, so that the whole strength thus spent 
 would be equal, in a day, to twelve hundred and fifty 
 pounds, which ought to be exerted in stirring the soil and 
 destroying weeds. Or, take another instance : A farm 
 wagon usually weighs nearly half a ton ; many might be 
 
 Fig. 86. 
 W 
 
 C 
 
 Badly-formed fork handle. 
 
 reduced fifty pounds in weight by proportioning every 
 part exactly to the strength required. How much, then, 
 should we gain here? Every farmer who drives a wagon 
 with its needless fifty pounds, on an average of only five 
 miles a day, draws an unnecessary weight every year 
 equal to the conveyance of a heavy wagon-load to a dis- 
 tance of forty miles. 
 
 Now a knowledge of mechanical science will often ena- 
 ble the farmer, when he selects and buys his implements, 
 to judge correctly whether every part is properly adapted 
 to the required strength. We shall suppose, for instance, 
 that he intends to purchase a common pitchfork. He 
 finds them differently formed, although all are made of the 
 
 Fig. 87. 
 Os 
 
 Badly-formed fork handle. 
 
 best materials. The handles of some are of equal size 
 throughout. Some are smaller near the fork, as in fig. 86, 
 and others are larger at the same place, as in fig. 87. 
 Now, if he understands the principle of the lever, he 
 knows that both of these are wrongly made, for the right 
 hand placed at a is the fulcrum, where the greatest 
 strength is needed, and therefore the one represented by 
 fig. 88 is both stronger and lighter than the others. 
 
PRINCIPLES IN THE STRUCTURE OF IMPLEMENTS. 77 
 
 Again, hoe handles, not needing much strength, chiefly 
 require lightness -and convenience for grasping. Hence, 
 in selecting from two such as are represented in the annex- 
 ed figures, the one should be chosen which is lightest near 
 
 Fig. 88. 
 
 Well-formed fork handle. 
 
 the blade, nearly all the motion being in that direction, 
 because the upper end is the centre of motion. The right 
 hand, at «, acting partly as the fulcrum, the hoe handle 
 should be slightly enlarged at that place. Fig. 89 rep- 
 resents a well-formed handle ; fig. 90, a clumsy one. Rake 
 handles should be made largest at the middle, or where 
 the right hand presses. Rake-heads should be much 
 larger at the centre, and tapering to the ends, where the 
 stress is least, the two parts operating as two distinct lev- 
 Fig. 89. 
 a. 
 
 Well-formed hoe handle. 
 
 ers, acting from the middle. Wood horse-raJces might be 
 made considerably lighter than they usually are by ob- 
 serving the same principles. The greatest strength requir- 
 ed for plow-beams is at the junction with the mould-board, 
 and the least near the forward end, or furthest from the 
 fulcrum or centre of motion. 
 
 Now it may be that the farmer who has had much ex- 
 perience may be able to judge of all these things without 
 
 Fig. 90. 
 
 c? 
 
 Badly-formed hoe handle. 
 
 a knowledge of the science. But this scientific knowledge 
 would serve to strengthen his experience, and enable him 
 to judge more accurately and understandingly by showing 
 him the reasons ; and in many cases, where new imple- 
 ments were introduced, he might be enabled to form a 
 
78 
 
 MECHANICS. 
 
 good judgment before he had incurred all the expense and 
 losses of unsuccessful trials. 
 
 Even so simple a form as that of an ox-yoke is often 
 made unnecessarily heavy. Fig. 91 represents one that is 
 faulty in this respect, by having been cut from a piece of 
 
 Ficr. 91. 
 
 
 timber as wide as the dotted lines a c / and being thus 
 weakened, it requires to be correspondingly large. Fig. 
 92 is equally strong, much lighter, and is easily made from 
 a stick of timber only as wide as a b in the former figure. 
 In the heavier machines, it is necessary to know the de- 
 gree of taper in the different parts with accuracy. A 
 thorough knowledge of science is needed to calculate this 
 
 Fig. 92. 
 
 with precision, but a superficial idea may be given by cuts. 
 If a bar of wood, formed as in a (fig. 93), be fixed in a 
 wall of masonry, it will possess as much strength to sup- 
 port a weight hung on the end as if it were the same size 
 throughout, as b. The first is equally strong with the 
 second, and much lighter.* The same form doubled must 
 
 * The simple st} Y le of this work precludes an explanation of the mode 
 of calculation for determining the exact form. Where the stick taper8 
 only on one side, it is a common parabola ; if on all sides, a cubic 
 parabola, 
 
VARIOUS EXAMPLES. 
 
 79 
 
 be given if the bar is supported at the middle, with a 
 weight at each end, or with the weight at the middle, 
 supported at each end, as c. This form, therefore, is a 
 proper one for many parts of implements, as the bars of 
 whiffle-trees, the rounds of ladders, string-pieces of bridges, 
 and any cross-beams for supporting weights. The proper 
 form for rake-teeth and fence-posts, the pressure being 
 nearly alike on all parts, is nearly that of a long wedge, 
 or with a straight and uniform taper. Therefore a fence- 
 post of equal size throughout contains nearly twice as 
 much timber as is needed for strength only. 
 
 The form of these parts must, however, be modified to 
 suit circumstances ; as whiffle-trees must be large enough 
 
 Fig. 93. 
 
 at the ends to receive the iron hooks, wagon-tongues for 
 ironing at the end, and spade handles for the easy grasp 
 of the hand. 
 
 The axle-trees of wagons must be made not only strong 
 in the middle, or at centre of pressure, but also at the en- 
 trance of the hub ; because the wheels, when thrown side- 
 wise in a rut, or on a sideling road, operate as levers at 
 that point, a and b (fig. 94), show the manner in which 
 the axles of carts may be rendered lighter without lessen- 
 ing the strength, a being the common form, and b the im- 
 proved one. 
 
80 MECHANICS. 
 
 Sometimes several forces act at once on different parts. 
 For example, the spokes of wagon- wheels require strength 
 at the hub for stiffening the wheel ; they must be strong 
 in the middle to prevent bending, and large enough at 
 
 the outer ends, where they are soonest weakened by de- 
 cay. Hence there should be nearly a uniform taper, 
 slightly larger at the middle, and with an enlargement at 
 the outer end, as c (fig. 94). 
 
 A very useful rule in practice, in giving strength to 
 structures, is this : The strength of every square beam or 
 stick to support a weight increases exactly as the width 
 increases, and also exactly as the square of the depth in- 
 creases. For example, a stick of timber eight inches wide 
 and four inches deep (that is, four inches thick), is exactly 
 twice as strong as another onlv four inches wide, and with 
 
 O J 7 
 
 the same depth. It is twice as wide, and consequently 
 twice as strong ; that is, its strength increases just as the 
 width increases, according to the rule given. But where 
 one stick of timber is twice as deep, the width being the 
 same, it is four thnes stronger ; if three times as deep, it 
 is nine thnes stronger, and so on. Its strength increases 
 as the square of the depth, as already stated. The same 
 rule will show that a board an inch thick and twelve inch- 
 es wide will be twelve times as stronsr when edgewise as 
 when lying flat. Hence the increase in strength given to 
 whiffle-trees, fence-posts, joists, rafters, and string-pieces 
 to farm-bridges, by making them narrow and deep. 
 
CALCULATING THE STRENGTH OF PaF.TS. 51 
 
 Again, the strength of a round stick increases as the cube 
 of the diameter increases ; that is. a round piece of wood 
 
 three inches in diameter is eight tunes u strong as one an 
 inch and a half in diameter, and twenty-seven time- 
 strong as one an inch in diameter. This rule shows that 
 a fork handle an inch and a halt' in diameter at the middle 
 9 much stronger than one an inch and a quarter in 
 diameter, as seven is greater than four. Xcw this rule 
 would enable the farmer to ascertain this without break- 
 ing half a dozen fork handles in trying the experiment, 
 and it would enable the manufacturer to know, without 
 
 Kg. 95. 
 
 the labor of trying many experiments, that if he makes a 
 fork handle an inch and a half at the middle, tapering a 
 quarter of an inch toward the ends, it will enable the 
 workman to lilt with it nearly twice as much hay as with 
 one an inch and a quarter only through its whole length. 
 A mode of adding strength to light bars of wo J 
 
 means of braces, is shown in fig. 95, representing light 
 .me-trees. stiffened by iron rods in a simple manner. 
 The same method is sometimes adopted to advantage in 
 making light fruit ladders, and for other purposes, 
 
 CHAPTER VI. 
 FEICTIOX. 
 
 The subject of friction lias been postponed, or merely 
 
 alluded to, to prevent the confusion of considering too 
 
 many t *sat once. As it has an important influence on 
 
 the action of machines, it is worthy of careful investigation. 
 
 4* 
 
82 MECHANICS. 
 
 It is familiar to most persons, that when two surfaces 
 slide over each other while pressing together, the minute 
 unevenness or roughness of their surfaces causes some ob- 
 struction, and more or less force is required. This resist- 
 ance is known as friction. 
 
 ROLLING FRICTION. 
 
 The term is also applied to the resistance of one body 
 rolling over another. This may be observed in various 
 degrees by rolling an ivory ball successively over a carpet, 
 a smooth floor, and a sheet of ice ; the same force which 
 would impel it only a few feet on the carpet would cause 
 it to move as many yards on a bare floor, and a still 
 greater distance on the ice. The two extremes may be 
 seen by the force required to draw a carriage on a deep 
 sandy or loose-gravel road, and on a rail-road. 
 
 NATURE OF FRICTION. 
 
 If two stiff bristle brushes be pressed with their faces 
 together, they become mutually interlocked, so that it 
 will be quite difficult to give them a sliding motion. This 
 may be considered as an extreme case of friction, and 
 serves to show its nature. In two pieces of coarse, rough 
 sandstone, or of roughly-sawed wood, asperities interlock 
 in the same way, but less in degree ; a diminished force is 
 consequently required in moving the two surfaces against 
 each other. On smoothly planed wood the friction is still 
 less ; and on polished glass, where the unevenness can not 
 be detected without the aid of a powerful magnifying 
 glass, it is reduced still further in degree. 
 
 ESTIMATING THE AMOUNT OF FRICTION. 
 
 In order to determine the exact amount of friction be- 
 tween different substances, the following simple and in- 
 
TO ASCERTAIN THE AMOUNT OF FRICTION. 83 
 
 genious contrivance is adopted : An inclined plane, a b 
 (fig. 96), is so formed that it may be raised to any desired 
 height by means of the arc of a circle and a screw. Lay 
 a flat surface of the substance we wish to examine upon 
 this inclined plane, and another smaller piece or block of 
 the same substance upon this surface ; then raise the plane 
 until it becomes just steep enough for the block to slide 
 down by its weight. Now, by measuring the degree of 
 slope, we know at once the amount of friction. Suppose, 
 for example, the two surfaces be smoothly-planed wood : 
 it will be found that the plane must be elevated about 
 half as high as its length ; therefore we know, by the 
 
 Fig. 96. 
 
 properties of the inclined plane, heretofore explained, that 
 it requires a force equal to one-half the weight of the 
 wooden block to slide it over a smooth wooden surface. 
 Some kinds of wood have more friction than others, but 
 this is about the average.* 
 
 From the result of this experiment we may learn that 
 to slide any object of wood across a floor requires an 
 amount of strength equal to one-half the weight of the 
 object. A heavy box, for instance, weighing two hundred 
 pounds, can not be moved without a force equal to one 
 hundred pounds. It also shows the impropriety of placing 
 
 * These experiments may be made with tolerable accuracy, by hook- 
 ing a spring-balance into any object of known weight, and then observ- 
 ing the comparative force as measured by the balance, to draw it over a 
 perfectly level surface. • - - : 
 
84 MECHANICS. 
 
 a heavy load upon a sled in winter for crossing a bare 
 wooden bridge or a dry barn floor, the friction between 
 cast-iron sleigh-shoes and rough sanded plank being nearly 
 equal to one-third of the whole weight.* Hence a load 
 of one ton (including the sled) would require a draught 
 equal to more than six hundred pounds, which is too much 
 for an ordinary single team. On bare unfrozen ground the 
 friction would be still greater. On a plank bridge, with 
 runners wholly of wood, it would be equal to half the 
 load. All these facts may be readily proved by actually 
 placing the sled on slopes of plank and of earth, and by 
 observing the degree of steepness required for sliding 
 down by its own weight. 
 
 In a similar way, we are enabled easily to ascertain the 
 force required to draw a wagon upon any kind of level 
 surface. Suppose, for example, that we wish to determine 
 the precise amount of force for a wagon weighing, with 
 its load, one ton, on a plank road. Select some slight de- 
 scent, where the wagon will barely run with its own 
 weight. Ascertain by a level just what the degree of de- 
 scent is ; then divide the weight of the wagon by the de- 
 gree of the slope, and we shall have the force sought for. 
 To make this rule plainer by an example : It will be found 
 that a good, newly-laid plank track, if it possess a de- 
 scent of only one foot in fifty feet distance, will be suffi- 
 cient to give motion to an easy-running Avagon ; therefore 
 we know that the strength required to draw it on a level 
 will be only one-fiftieth part of a ton, or forty pounds. 
 
 The resistance offered to the motion of a wagon by a 
 Macadam road, by a common dry road, and by one with 
 six inches of mud, may be readily determined in the same 
 way by selecting proper slopes for the experiment. If by 
 such trials as these the farmer ascertains the fact that a 
 
 * On clean hard wood, with polished metallic shoes, the friction 
 "would be much less, or a fourth or fifth. 
 
EESULTS WITH THE DYNAMOMETEE. 85 
 
 few inches of mud are sufficient to retard his wagon so 
 much that it wiJl not run of its own weight down a slope 
 of one foot in four (and few common roads are ever 
 steeper), then he may know that a force equal to one-fourth 
 the whole weight of his wagon and load will be required 
 to draw it on a level over a similar road — that is, the 
 enormous force of five hundred pounds will be needed for 
 one ton, of which many wagons will constitute nearly one- 
 half. Hence he can not fail to see the great importance, 
 for the sake of economy, and humanity to his team, of 
 providing roads, whether public or private, of the hardest 
 and best materials. 
 
 EESULTS WITH THE DYNAMOMETER. 
 
 Another mode of determining the resistance of roads is 
 by means of the Dynamometer* It resembles a spring- 
 balance, and one end is fastened to the wagon and the 
 other end connected with the horses. The force applied 
 is measured on a graduated scale, in the same way that 
 the weight of any substance is measured with the spring- 
 balance. A more particular description of this instrument 
 will be given hereafter. 
 
 Careful experiments have been made with the dynamom- 
 eter to ascertain accurately the resistance of various kinds 
 of roads. The following are some of the results : 
 
 On a new gravel road, a horse will draw eight times as 
 much as the force applied ; that is, if he exerts a force 
 equal to one hundred and twenty-five pounds, he will 
 draw half a ton on such a road, including the weight of 
 the wagon, the road being perfectly level. 
 
 On a common road of sand and gravel, sixteen times as 
 much, or one ton. 
 
 On the best hard-earth road, twenty-five times as much, 
 or one and a half tons. 
 
 From two Greek words, dunamis, power, and metreo i to measure. 
 
 
86 MECHANICS. 
 
 On a common broken-stone road, twenty-five to thirty- 
 six times as much, or one and a half to two and a quarter 
 tons. 
 
 On the hest broken-stone road, fifty to sixty-seven times 
 as much, or three to four tons. 
 
 On a common plank-road, clean, fifty times as much, or 
 three tons. 
 
 On a common plank-road, covered thinly with sand or 
 earth, thirty to thirty-five times as much, or about two 
 tons. 
 
 On the smoothest oak plank-road, seventy to one hund- 
 red times as much, or four and a half to six tons. 
 
 On a highly-finished stone track-way, one hundred and 
 seventy times as much, or ten and a half tons. 
 
 On the best rail-road, two hundred and eighty times as 
 much, or seventeen and a half tons. 
 
 The firmness of surface given to a broken-stone road by 
 a paved foundation was found to lessen the resistance 
 about one-third. 
 
 On a broken-stone road it was found that a horse could 
 draw only about two-thirds as much w r hen it was moist 
 or dusty as when it was dry and smooth; and when 
 muddy, not one-half as much. When the mud was thick, 
 only about one quarter as much. 
 
 The character of the vehicle has an influence on the 
 draught. Thus, a cart, a part of the load of which is sup- 
 ported by the horse, usually requires only about two-thirds 
 the force of horizontal draught needed for wagons and 
 carriages. On rough roads the resistance is slightly 
 diminished by springs. 
 
 On soft roads, as earth, sand, or gravel, the number of 
 pounds draught is but little affected by the speed ; that is, 
 the resistance is no greater in driving on a trot than on a 
 walk ; but on hard roads it becomes greater as the velocity 
 increases. Thus a carriage on a dry pavement requires 
 one-half greater force when the horses are on a trot than 
 
WIDTH 0? WHEELS. 87 
 
 on a walk ; but on a muddy road the difference between 
 the two rates of speed is only about one-sixth. On a rail- 
 road, where a draught of ten pounds will draw a ton ten 
 miles an hour, the resistance increases so much at a hisfh 
 degree of speed as to require a force of fifty pounds per 
 ton at sixty miles an hour — that is, it would require five 
 times as much actual power to draw a train one hundred 
 miles at the latter rate as at the former ; but as the speed 
 is six times as great, the actual force during a given time 
 would be five times six, or thirty times as great. 
 
 WIDTH OF WHEELS. 
 
 Wheels with wide tire run more easily than narrow tire, 
 on soft roads ; on hard, smooth roads, there is no sensible 
 difference. Wide tire is most advantageous on gravel and 
 new broken-stone roads, both by causing the vehicles to 
 run more easily, and by improving the surface. For the 
 latter reason, the New York turnpike law allows six-inch 
 wheels to pass at half price, and twelve-inch wheels to pass 
 free of toll. Wheels with broad tire on a farm would pass 
 over clods, and not sink between them ; or would only 
 press the surface of new meadows, without cutting the 
 turf. But where the ground becomes muddy, the mud 
 closes on both sides of the rim, and loads the wheels. On 
 clayey soils, narrow tire unfits the roads for broad wheels. 
 For these reasons, broad wheels are decidedly objection- 
 able for clayey or soft soils, and they are chiefly to be 
 recommended for broken-stone roads, and gravelly, or dry, 
 sandy localities. They are also much better for the wheels 
 of sowing or drilling machines, which only pass over 
 mellowed surfaces. 
 
 The larger the wheels are made, the more easily they 
 run ; thus a wheel six feet in diameter meets with only 
 half the resistance of a wheel three feet in diameter. 
 
 A flat piece of wood, sliding on one of its broad sur- 
 
88 MECHANICS. 
 
 faces, is subject to the same amount of friction as when 
 sliding upon its edge. Hence the friction is the same, 
 provided the pressure be the same, whether the surface be 
 small or large.* Or, in other words, if the surfaces are 
 the same, a double pressure produces a double amount of 
 friction ; a triple pressure, a triple amount, and so on. 
 
 A narrow sleigh-shoe usually runs with least force, for 
 two reasons : first, its forward part cuts with less resist- 
 ance through the snow ; and, secondly, less force is re- 
 quired to pack the narrow track of snow beneath it. The 
 only instance in which a wide sleigh-shoe would be best, is 
 where a crust exists that would bear it up, and through 
 which a narrow one would cut and sink down. 
 
 VELOCITY. 
 
 Friction is entirety independent of velocity ; that is, if 
 a force of ten pounds is required to turn a carriage wheel, 
 this force will be ten pounds, whether the carriage is 
 driven one or five miles per hour. Of course, it will re- 
 quire five times as much force to draw five miles per hour, 
 because five times the distance is gone over ; but, measured 
 by a dynamometer or spring-balance, the pressure would 
 be the same. In precisely the same way, the weight of a 
 stone remains the same, whether lifted slowly or quickly. 
 If the friction of the wheels of a wagon on their axles be 
 equal to ten pounds, driving the horse fast or slowly will 
 not increase or diminish it. But fast driving will require 
 more strength, for the same reason that a man would need 
 more strength to carry a bag of wheat up two flights of 
 stairs than one, in one minute of time. 
 
 FRICTION AT THE AXLE. 
 
 A carriage wheel, or any other wheel revolving on an 
 
 * Generally speaking, this is very nearly correct ; but when the pres- 
 sure is intense, the friction is slightly less on the smaller surface. 
 
SIZE OF WHEELS ON EOADS. 
 
 89 
 
 Fig. 97. 
 
 axle, will run more easily as the axle is made smaller. 
 This is not owing to the rubbing surfaces being less in 
 size, as some mistakenly suppose, for it has just been 
 shown that this makes very little or no difference, pro- 
 vided the pressure is the same; but it is owing to the 
 leverage of the wheel on the friction at the axis ; and the 
 smaller the axle, the greater is this leverage ; for, if the 
 axle, a (fig. 97), be six 
 inches in circumference, 
 and the wheel, b c, be 
 ten feet in circumference, 
 then the outer part of 
 the wheel will move 
 twenty times further 
 than the part next the 
 axle. Therefore, accord- 
 ing to the rule of virtual 
 velocities (already ex- 
 plained,) one ounce of 
 force at the rim of the 
 wheel will overcome tAventy ounces of friction at the 
 axle ; or if the axle were twice as large, then, according 
 to the same rule, it would require two ounces to over- 
 come the same friction acting between larger surfaces. 
 
 For this reason, large wheels in wheel-work for multi- 
 plying motion, if not made too heavy, run with less force 
 than smaller ones, the power acting upon a larger lever. 
 Horse-powers for thrashing-machines, consisting chiefly of 
 a large, light crown-wheel, well stiffened by brace-work, 
 have been found to run with remarkable ease; a good 
 example of which exists in what is known as Talpirts 
 horse-power, when made in the best manner. 
 
 .....^Srarf**' 
 
 FRICTION-WHEELS. 
 
 On the preceding principle, friction-wheels or friction- 
 rollers are constructed, for lessening as much as possible 
 
90 
 
 MECHANICS. 
 
 Fisr. 9S. 
 
 Friction-ivheels. 
 
 Ficr. 99. 
 
 the friction of axles in certain cases. By this contrivance, 
 the axle, a (fig. 98), instead of revolving in a simple hole 
 or cavity, rests on or between the edges 
 of two other wheels. As the axle re- 
 volves, the edges turn with it, and the 
 rubbing of surfaces is only at the axles 
 of these two wheels. If, therefore, these 
 axles be twenty times smaller than the wheels, the friction 
 will be only one-twentieth the amount without them. 
 This contrivance has 
 been strongly recom- 
 mended and con- 
 siderably used for 
 the cranks of grind- 
 stones (fig. 99), but 
 it was not found to 
 answer the intended 
 purpose so well as 
 was expected, for 
 the very plain reason 
 that, in using a 
 grindstone, nearly all the friction is at the circumference, 
 or between the stone and the tool, which friction-wheels 
 could not, of course, remove. 
 
 Grindstone on Friction-wheels. 
 
 LUBRICATING SUBSTANCES. 
 
 Lubricating substances, as oil, lard, and tallow, applied 
 to rubbing surfaces, greatly lessen the amount of friction, 
 partly by filling the minute cavities, and partly by sepa- 
 rating the surfaces. In ordinary cases, or where the 
 machinery is simple, those substances are best for this 
 purpose which keep their places best. Finely-powdered 
 black-lead, mixed with lard, is for this reason better for 
 greasing carriage wheels than some other applications. 
 Drying oils, as linseed, soon become stiff by drying, and 
 
LUBRICATING SUBSTANCES. 91 
 
 are of little service. Olive oil, on the contrary, and some 
 animal oils, which scarcely dry at all, are generally pre- 
 ferred. To obtain the full benefit of oil, the application 
 must be frequent. 
 
 According to the experiments made with great care by 
 Morin, at Paris, the friction of wooden surfaces on wooden 
 surfaces is from one quarter to one-half the force applied ; 
 and the friction of metals on metals, one-fifth to one- 
 seventh — varying in both cases with the kinds used. 
 Wood on wood was diminished by lard to about one-fifth 
 to one-seventh of what it was before ; and the friction of 
 metal on metal was diminished to about half what it was 
 before ; that is, the friction became about the same in both 
 cases after the lard was applied. 
 
 To lessen the friction of wooden surfaces, lard is better 
 than tallow by about one-eighth or one-seventh; and tal- 
 low is better than dry soap about as two is to one. For 
 iron on wood, tallow is better than dry soap about as five 
 is to two. For cast-iron on cast-iron, polished, the friction 
 with the different lubricating substances is as follows : 
 
 Water 31 
 
 Soap ^ 
 
 Tallow 
 
 Lard. 
 
 7 
 
 Olive oil 6 
 
 Laid and black-lead 5 
 
 When bronze rubs on wrought iron, the friction with 
 lard and black-lead is rather more than with tallow, and 
 about one-fifth more than with olive oil. With steel on 
 bronze, the friction with tallow and with olive oil is about 
 one-seventh less than with lard and black-lead. 
 
 As a general rule, there is least friction with lard when 
 hard wood rubs on hard wood ; with oil, when metal rubs 
 on wood, or metal on metal— being about the same in 
 each of all these instances. 
 
 In simple cases, as with carts and wagons, where the 
 
92 MECHANICS. 
 
 friction at the axle is but a small portion of the resistance,* 
 a slight variation in the effects in the lubricating sub- 
 stance is of less importance than retaining its place. In 
 more complex machinery, as horse-powers for thrashing- 
 machines, friction becomes a large item, unless the parts 
 are kept well lubricated with the best materials. 
 
 Leather and hemp bands, when used on drums for 
 wheel-work, should possess as much friction as possible, to 
 prevent slipping, thus avoiding the necessity of tightening 
 them so much as to increase the friction of the axles. 
 Wood with a rough surface has one-half more friction 
 than when worn smooth ; hence moistening and rasping 
 small drums may be useful. Facing with buff leather or 
 with coarse thick cloth also accomplishes a useful purpose. 
 It often happens that wetting or oiling bands will prevent 
 slipping, by keeping their surfaces soft, and causing them 
 to fit more closely the rough surface of the drum. 
 
 ADVANTAGES OF FRICTION. 
 
 Although friction is often a serious inconvenience, or 
 loss, in lessening the force of machines, there are many 
 instances in which it performs important offices in nature 
 and in works of art. " Were there no friction, all bodies 
 on the surface of the earth would be clashing against each 
 other; rivers would dash with an unbounded velocity, and 
 we should see little besides collision and motion. At 
 present, whenever a body acquires a great velocity, it soon 
 loses it by friction against the surface of the earth. The 
 friction of water against the surfaces it runs over soon 
 reduces the rapid torrent to a gentle stream ; the fury of 
 
 * If the friction at the axle be one-twelfth of the force, and the diam- 
 eter of the wheels ten times as great as the diameter of the axle, the 
 friction at the axles will be reduced to one-twelfth of a tenth, or one 
 hundred and twentieth part of the force, according to the law of virtual 
 velocities as applied to the wheel and axle. 
 
FRICTION NECESSARY TO EXISTENCE. 93 
 
 the tempest is lessened by the friction of the air on the 
 face of the earth, and the violence of the ocean is subdued 
 by the attrition of its own waters. 
 
 " Its offices in the works of art are equally important. 
 Our garments owe their strength to friction, and the 
 strength of ropes depends on the same cause ; for they are 
 made of short fibres pressed together by twisting, causing 
 a sufficient degree of friction to prevent the sliding of 
 the fibres. Without friction, the short fibres of cotton 
 could never have been made into such an infinite variety 
 of forms as they have received from the hands of ingenious 
 workmen." * Deprived of this retaining force, the parts 
 of stone walls, piles of wood and lumber, and the loads 
 of carts and wagons, as well as the wheels themselves, 
 would slide without restraint, as if their surfaces were of 
 the most icy smoothness, and walking without support 
 would be impossible. 
 
 The tractive power of locomotives depends on the fric- 
 tion between the wheels and iron rails, which is equal to 
 about one-fifth of the weight of the engine ; that is, a 
 locomotive weighing twenty-five tons will draw with a 
 force of five tons, without producing slipping of the 
 wheels. 
 
 CHAPTER VII. 
 
 PRINCIPLES OF DRAUGHT. 
 
 An examination of the nature or laws of friction enables 
 us to ascertain the best line of draught for teams when 
 attached to wagons and carriages. If there were no fric- 
 tion whatever upon the road, the best direction for the 
 
 * Encyclopaedia Americana. 
 
94 MECHANICS. 
 
 traces would be parallel with its surface, that is, on a level ; 
 but as there is always some friction, the line of draught 
 should be a little rising, so as to tend to lessen the pressure 
 of the wheels on the road. 
 
 Now this upward direction of the draught should 
 always be exactly of such a slope, that if the same slope 
 were given to the road, the wagon would just descend by 
 its weight. The more rough or muddy the road is, the 
 steeper should be this line of draught or direction of the 
 traces.* On a good common road it would be much less, 
 and on a plank-road but slightly varied from a horizontal 
 direction. On a rail-road the line should be about level. 
 On good sleighing, some of the strength of the team is 
 commonly lost by too steep a line of draught. 
 
 The reason of this rule may be understood by the fol- 
 lowing explanation : Let the obstruction, a, in the annexed 
 Fi<>\ 100. figure (fig. 100) represent the friction the 
 
 ^ wheel constantly meets with in rolling 
 over a common road. To overcome this 
 "friction, the wheel must rise in the di- 
 rection of the dotted line. Therefore, if 
 a the force is made to pull in this direction, 
 ^fesSt^- fa w iu aC £ more advantageously than in 
 any other, because this is the course in which the centre of 
 the wheel must move. Now if a downward slope were 
 given to the road at this obstruction, the wheel and the 
 obstruction would both be brought on a level, and the 
 wheel would move with the slightest degree of force. 
 
 It will be understood from the preceding rule that a sled 
 running on bare ground should be drawn by traces bearing 
 upward in a large degree. The same remark will apply to 
 the plow, which slides upon the ground in a similar way, 
 with the pressure of the turning sod as a load. Hence 
 
 * Provided the wheels are not made smaller for this purpose, increasing 
 their resistance. 
 
PRINCIPLES OP DRAUGHT APPLIED TO PLOWS. 95 
 
 the reason that a great saving of strength results from the 
 use of short traces in plowing. An experiment was tried 
 for the purpose of testing this reasoning ; first, with traces 
 of such length that the horses' shoulders were about ten 
 feet from the point of the plow ; and secondly, with the 
 distance increased to about fifteen feet. With the short 
 traces a strength was required equal to 2^ cwt., but with 
 the long traces it amounted to 3^- cwt. 
 
 But the draught-traces may be made too short. When 
 this is the case, the Fi - 101 - 
 
 plow is necessarily ~A" 
 
 thrown too much upon ^=*^. ,*-'' \ 
 
 its point, to keep it "~""^jp ^~~fl "" j 
 
 from flying out of the >» g^^ -- — ' — i 
 
 ground, by which means it works badly in turning the fur- 
 row. In addition to this evil, the plowman is compelled to 
 bear down heavily, adding to the friction of the sole on 
 the bottom of the furrow, and greatly increasing his labor. 
 
 The line of draught should be so adjusted that the plow 
 may press equally all along on its sole or bottom, which 
 will cause it to run evenly and with a steady motion. 
 
 Fig. 102. 
 
 Line of draujht for the plmv. 
 
 This end will be effected by giving the traces or draught- 
 chain just such a length that the share of the plow (or 
 centre of resistance), the clevis, and the point of draught 
 at the horses' shoulders (or the ring of the ox-yoke) shall 
 all form a straight line. This is shown in the annexed 
 figure, where A is the place of the ox-ring or of the for- 
 ward extremity of the traces (fig. 101). 
 
 The centre of resistance will vary with the depth of 
 
9G MECHANICS. 
 
 plowing. When the furrow is shallow (as shown by the 
 lines G H, fig. 102), the centre of resistance will be at A, 
 requiring the team to be fastened to the lower side of the 
 clevis, C ; but when the depth is greater (as shown by F 
 H), the centre of resistance will be at B, requiring a 
 higher attachment to the clevis ; the point of draught, E, 
 remaining the same in both cases. 
 
 So great is the difference between an awkward and skill- 
 ful adjustment of the draught to the plow, that some 
 workmen with a poor implement have succeeded better 
 than others with the best; and plows of second quality 
 have sometimes, for this reason, been preferred to those 
 of the most perfect construction. 
 
 COMBINED DRAUGHT OF ANIMALS. 
 
 When several animals are combined together, it is of 
 great importance that they should be exactly matched in 
 gait. Much force is Fig. 103. 
 
 often wasted when fc=qf= =$ 6= 
 they draw unsteadily 
 or unevenly. It is 
 more difficult to di- 
 vide the draught equally among several animals when 
 placed one before the other, than when arrayed abreast, for 
 some may hang back, and others do more than their share, 
 unless a skillful driver is always on the watch. It also hap- 
 pens, when thus arranged, that the forward horses draw hori- 
 zontally, while the hindmost one draws in a sloping line, 
 and the line of draught between them thus beincr crooked, 
 more or less force is lost. This may be, however, remedied 
 in part by placing the taller animals forward, and the 
 smaller behind. 
 
 For these reasons, when only three horses are used, they 
 should always be placed abreast. The force required for 
 each may be rendered exactly equal by the whiffle-trees 
 
COMBINED DRAUGHT OP ANIMALS. 
 
 97 
 
 usually employed for this purpose, and represented in fig. 
 103, where two horses are attached to the shorter end, and 
 
 Fisr. 104 
 
 Whipplc-tree for three horses. 
 
 the third to the longer end of the common bar. Another 
 ingenious but more complex arrangement is shown by fig. 
 104, where also the ,.. «_ B 
 
 ' Fig. 105. 
 
 central horse has 
 only half the two 
 others, by being at- 
 tached to the longer 
 ends of the inter- 
 mediate bars. An- 
 other, and a more 
 perfect contrivance, 
 is Potters Three- 
 horse Clevis, re- 
 presented by fig. 105. It consists of two wheels to- 
 gether, one twice the diameter of the other, and each 
 having a groove in which a chain runs. The chains 
 are fastened to the respective wheels, so that the 
 single horse draws on the larger wheel, against the two 
 horses on the smaller. With common whiflle-trees, the 
 relative draught of each horse is maintained only when 
 they draw evenly ; with Potter's there is no variation at 
 any time. It is made by E. M. Potter, Kalamazoo, Mich. 
 Fig. 108 represents the mode of attaching four horses in 
 draught, their force being equalized by passing the chain 
 round the wheel in the pulley-block, «, security being pro- 
 vided that the hindmost pair shall not encroach on the 
 5 
 
98 
 
 MECHANICS. 
 Fig. 106. 
 
 forward pair, by connecting the end of the chain at the 
 same time to the plow. 
 
 wiee's single-teee. 
 
 This is used exclusively for plowing in orchards, and is 
 worthy of notice here. The leather traces are hooked at 
 Fig. 107. the rear of the wooden 
 
 bar, and, passing around 
 the ends, prevent the 
 possibility of being 
 caught in the bark of the 
 trees. The teamster may 
 therefore drive as closely as he chooses without danger of 
 injury. For this reason he is able to turn over the whole 
 surface without leaving an unplowed strip along the row. 
 
 CONSTEUCTION AND USE OF THE DYNAMOMETEE. 
 
 The dynamometer, or force-measurer, has been already 
 briefly alluded to, but a more particular description will 
 be useful. In the construction and selection of all ma- 
 chines and implements that require much power in their 
 use, the dynamometer is indispensable, although at present 
 but little known. As an example of its utility, the farmer 
 may wish to choose between two plows which, so far as 
 he can perceive, may do their work equally well ; but 
 this instrument, when applied, may show that the team 
 
THE DYNAMOMETER. 
 
 99 
 
 must draw with a force equal to 400 pounds in mov- 
 ing one of them through the soil, while 300 pounds would be 
 sufficient for the other. He would, therefore, select the one 
 of easiest draught, and by doing so would save the labor of 
 one day in four to his team, or twenty-five days in a hund- 
 red, which would be worth many times the cost of the 
 trial. The same advantage might be derived in the selec- 
 tion of harrows, cultivators, horse-rakes, straw-cutters, and 
 all other implements drawn by horses or worked by men. 
 Again, the farmer may be in doubt in choosing between 
 two thrashing-machines, which in other respects may work 
 equally fast and well ; but the dynamometer may show 
 that one requires a severer exertion from the team, and 
 consequently is less valuable for use. 
 
 The operation of this instrument may be readily under- 
 
 Dynamometer, or Force-measurer. 
 
 stood by fig. 108, where b represents the dynamometer, 
 
 Fi<?. 109. 
 
 Elliptic Dynamometer. 
 
 made precisely similar to a large and stiff spring balance, 
 
100 
 
 MECHANICS. 
 
 with one hook attached to the plow and the other to the 
 whiffle-tree. The amount of force required to draw the plow 
 is accurately measured on the scale by the index or pointer,^. 
 
 Sometimes the motion of this index is multiplied, or 
 made greater and more easily seen, by means of a cog- 
 wheel and rack- work ; but this renders the instrument, at 
 the same time, more complex. 
 
 Another form of this instrument is shown in fig. 109, 
 
 Ffff. no. 
 
 Elliptic Dynamometer, in compact form : S S, spring; F, cross-lever for moving 
 
 in.dcx. 
 
 where the ends of the oval spring, Q Q, are attached to 
 the plow and draught. The harder the force exerted by 
 the team, the closer together will the sides of this spring 
 be brought, causing the rod, E, to press against the index 
 or pointer, and showing the precise degree of force on the 
 circular scale. 
 
 An improvement, by rendering the instrument more 
 compact, is shown in fig. 110, where S S is the spring, and 
 directly over it is the graduated scale. 
 
SELF-RECORDING DYNAMOMETER. 
 
 101 
 
 An inconvenience occurs in the use of the instruments 
 now described from the rapid ! vibration of the index, re- 
 sulting from the quick changes in the force, partly from 
 inequalities in the soil, and partly from the unsteady mo- 
 tion of the horses. The vibration is sometimes so great 
 that the index can hardly be seen, rendering it difficult to 
 measure the average force. This inconvenience has been 
 removed, in a great degree, by attaching to one end of 
 the index, E (fig. 110), a piston working in a cylinder filled 
 with oil, C ; this piston has a small hole through it, through 
 which the oil passes from one side to the other as the 
 draught varies, but not fast enough to allow any sudden 
 motion. 
 
 SELF-RECORDING DYNAMOMETER. 
 
 A less simple but more perfect instrument is the Self- 
 recording Dynamometer, which marks accurately all the 
 
 Fte. 111. 
 
 -< — ^— -' 2fatio7i of /taper 
 
 320 
 
 *nn 
 
 
 1 h 
 
 260 
 
 
 „.ii j Hi iii iili 
 
 2G0 
 
 
 klllilMillii 
 
 840 
 
 I " 
 
 
 .I'!.: i:i|,!T./.T:!; 
 
 220 
 
 ,11 Jili, II 
 
 
 \ iii,j i |.,iJju |i 
 
 200 
 
 
 «l!l!l!l1IIH!lil l ii|il!iP 
 
 
 
 180 
 
 
 IHHI 
 
 
 
 160 
 
 
 j, i 
 
 
 
 140 
 
 
 ■' i 
 
 
 
 120 
 
 
 
 
 
 100 
 
 
 
 
 
 80 
 
 1 
 
 
 
 60 
 
 J 
 
 
 
 40 
 
 j 
 
 
 
 20 
 
 i ■ ■ 
 
 I 
 
 
 
 
 The markings of the Self-recording Dynamometer. 
 
 vibrations on a slip of paper while the plow is in opera- 
 tion. A pencil is fixed to the index, and presses, by means 
 of a spring, against the paper, thus giving a true register 
 
102 MECHANICS. 
 
 of the force exerted. To prevent the pencil from con- 
 stantly marking on the same line, the paper is made to 
 move slowly in a side direction, so that all the vibrations 
 are shown, as represented in fig. Ill, and they may be ac- 
 curately examined and read off at leisure, a and b repre- 
 senting the forces of two different plows, drawn through 
 a single furrow across the field. The motion of the paper 
 is effected by being placed on two rollers, one of which 
 unwinds it from the other. This roller is made to turn by 
 Fig. 112. means of a wheel running on 
 
 the ground, which gives mo- 
 tion to the roller through an 
 endless chain, working a cog- 
 wheel by means of an endless 
 screw. The cylindrical dyn- 
 
 Self -recording Dynamometer. amometer, shown ill fig. 112, 
 
 is used for this purpose, lengthwise upon which the two 
 rollers are placed for holding the paper. With this in- 
 strument a permanent register might be made of the 
 force required for different plows, with an accuracy not 
 liable to dispute. 
 
 waterman's dynamometer. 
 
 All difficulties have been completely overcome by the 
 recent invention of H. Waterman, of Hudson, N. Y. His 
 dynamometer was used with entire success at the Auburn 
 reaper trial in 1866, and at the trial of plows at Utica, in 
 1867, under the Committee of the K. Y. State Agricul- 
 tural Society. A full description of all the parts would 
 require too much space for the character of this work ; the 
 following is a brief explanation of the mode of its opera- 
 tion: 
 
 This dynamometer is furnished with a spiral spring, 
 like those we have already described, working a piston in 
 a cylinder of water. To this, two dial plates are added 
 
Fig. 113. 
 
 waterman's dynamometer. 103 
 
 one of which shows, by a slowly revolving index, the ex- 
 act distance which the horses have traveled, without 
 looking at in for a distance of more than five miles. 
 The other dial plate gives a perfectly accurate record of 
 the whole force expended from the commencement of the 
 experiment to its termination. In other words, it takes 
 all the different and varying forces, and adds them accu- 
 rately in one aggregate or whole, seen at a glance on the 
 dial plate under the eye. 
 
 We shall attempt a brief description of the modes by 
 which the indexes on these two dial plates are moved. 
 
 The mode by which the distance traveled is recorded 
 will be easily understood. A wheel one yard in circum- 
 ference runs on the ground and communicates its 
 motion by a cord, to a wheel attached to the dyna- 
 mometer. This, by means of an endless screw 
 and cog-work, moves the index slowly around the 
 face, and thus records the distance traveled. There 
 are two parts of this portion of the apparatus, which 
 deserve a description. One is the wheel around 
 which the cord passes in connection with the wheel 
 which runs on the ground. It is very important that 
 the exact number of the revolutions of this wheel should be 
 maintained, as compared with those of the ground wheel. 
 This is regulated as follows : The groove in this wheel is 
 made by screwing together two beveled edged wheels, as 
 shown in the annexed section, fig. 113. By placing thin pa- 
 per between these two wheels, the width of the groove 
 may be varied with the utmost accuracy, and the cord 
 consequently let further in towards the centre. The other 
 part wmich we desire to notice, although not original in 
 this dynamometer, is the manner in which the index is car- 
 ried around the face of the dial plate. There are two 
 cog-wheels on the same axis, one with a hundred cogs, 
 and the other with ninety-nine — both fitting into the same 
 pinion. Consequently, when one has made the entire rev- 
 
104 
 
 MECHANICS. 
 
 olution, the other has fallen one cog behind, and a hund- 
 red revolutions are required for the index, placed upon 
 one of them, to come around again so as to coincide with 
 its first position. 
 
 The endless screw attached to the band- wheel already no- 
 ticed moves one cog at every yard advanced, and the in- 
 dex passing around in a hundred revolutions, it is obvious 
 that it will show 10,000 yards, or more than five miles. 
 
 We shall now attempt to describe that part of the ma- 
 chine which furnishes an accurate record of the force. In 
 doing this, we omit most of the details and vary some of 
 the parts, in order to make the explanation simpler and 
 clearer, the object being merely to explain the principle. 
 
 The band- wheel a, fig. 114, (shown also in fig. 113,) re- 
 volves once for every yard of onward movement, as already 
 Fi 114 stated. In doing 
 
 it causes the 
 
 so, 
 arm 
 
 d 
 
 c. to vi- 
 
 brate backwards 
 and forwards, on 
 a pin at d ; the 
 connecting; rod b 
 c being set near 
 the circumference 
 of the wheel &, this vibrating movement is shown by the 
 dotted lines at f and i. The slide h moves on this vibra- 
 ting rod, by being connected with the spiral spring already 
 described, which indicates the force of the draught ; the 
 stronger the draught, the further this slide is moved toward 
 c. When there is no draught at all, the rod e remains at 
 the pivot d, and has no motion; but as the slide h 
 is moved successively along the arm, this rod e is 
 thrust backwards and forwards, more or less, accord- 
 ing to the force of the draught. This thrusting move- 
 ment turns the ratchet wheel g faster or slow T er as this 
 force varies. A self-recording index is connected with 
 
waterman's dynamometer. 105 
 
 this wheel by an arrangement similar to that already de- 
 scribed for registering the distance. 
 
 This explanation shows the principle of the self-regis- 
 tering attachment, but in one respect it must be varied in 
 order to be entirely accurate. The ratchet wheel must 
 necessarily permit some play of the click or pawl, which 
 would soon lead to serious error. This is wholly prevent- 
 ed by facing the wheel with India rubber, and causing 
 the pawls to press this India rubber surface. 
 
 It will be observed that a movement of this wheel is 
 made at every revolution of the band-wheel, or once in 
 every yard ; and in traveling a hundred yards, a hundred 
 such movements are made. Every one of these may be 
 different in amount from the others, yet the whole sum 
 will be accurately measured. 
 
 It is absolutely essential that every part be finished with 
 perfect workmanship, so that there may be no play or 
 rattling of the teeth, producing loss of motion. Its 
 measurements have been entirely satisfactory, although its 
 records must necessarily vary with the condition of the 
 cutting edge of plows, with the running order of mow- 
 ing machines, the temper or sharpness of the knives, and 
 the skill of the manager or driver. 
 
 A more general use of the dynamometer would doubt- 
 less result in important advantage to farmers as w T ell as 
 plow-makers. The trials which have been made, both in 
 this country and in Europe, have proved that a great dif- 
 ference exists in plows, as to ease of draught, — some 
 plows requiring a force more than fifty per cent greater 
 than others, to turn a furrow of equal width and depth. 
 Hence the farmer who employs the plow which runs most 
 freely may accomplish as much by the use of two horses, 
 as another can do by using one of hard draught by em- 
 ploying three horses. 
 
 k* 
 
106 
 
 MECHANICS. 
 
 DYNAMOMETER FOE ROTARY MOTION. 
 
 All these dynamometers apply only to simple, onward 
 draught, as in plowing, drawing wagons, harrowing, etc. 
 There is another, represented in fig. 115, of very ingenious 
 but complex construction, which shows the force required 
 in working any rotary machine, such as thrashers, straw- 
 cutters, and mills, and showing, at the same time, the ve- 
 locity, and recording the number of revolutions made. 
 
 The whole machine is supported by a cast-iron framer 
 
 Fie. 115. 
 
 Dynamometer for measuring the force and velocity of thrashing-machines. 
 
 work, on four small wheels with flanges, like the wheels of 
 rail-cars, that it may be conveniently run up on a temporary 
 rail-way to the thrashing or other machine to be tried. 
 
 The band-wheel /, on the shaft e, is connected with the 
 machine under trial, and the force is supposed, in this in- 
 stance, to be applied by hand to the handle a, on the fly- 
 wheel. 
 
DYNAMOMETER FOR ROTARY MOTION. 107 
 
 When the fly-wheel is turned in the direction shown by 
 the arrow, it causes the two cog-wheels to revolve, and 
 moves the band in the direction shown by the other arrow. 
 JSTow, whatever force is required to turn the wheel f con- 
 nected with the machine under trial, must be overcome by 
 a corresponding force applied to the handle a, because 
 the wheel-work is so adjusted that this handle moves with 
 the same velocity as the band on the band-wheels. 
 
 The wheel f being connected by the band to the wheel 
 d, which is on the same axis or shaft as the cog-wheel /, 
 the resistance of the machine under trial tends to keep 
 the cog-wheel I from turning, until enough force is ap- 
 plied to the handle a, to set the cog-wheel h in motion. 
 Now the greater the resistance, the greater will be the 
 power needed at the handle. This power, therefore, is 
 measured accurately in the following manner : 
 
 The axle g, of the cog-wheel I, rests at its further end 
 in an oblong hole or mortise, which allows it liberty to play, 
 or rattle up and down within narrow limits. This same 
 axle, g, passes through a hole in the lever i so that when 
 it rattles up and down, it carries this lever up and down 
 with it. The other part of the lever turns on the shaft 
 h of the other cog-wheel. 
 
 Now when the man at the fly-wheel applies his force to 
 the handle a, the resistance of the machine under trial 
 causes the cog-wheel I to refuse to turn; consequently, 
 his force, instead of turning it, lifts it up in the mortise, 
 and raises the lever with it. As he increases his force 
 against the handle, let weights be hang on the lever, until, 
 at the very moment that the wheel begins to revolve, the 
 weights shall be just heavy enough to keep the lever down' 
 in the mortise. This weight, therefore, will measure the 
 exact force needed to turn the machine : the greater the 
 resistance of the machine, the greater must be the weight. 
 
 There is another weight, J, used to balance the lever 
 and cog-wheel I, while the machine is at rest, or before 
 
108 MECHANICS. 
 
 the force is applied to it, so that the weight at m shall rep- 
 resent the force truly. The weight m is, of course, to be 
 multiplied by the power it exerts on the lever i, which 
 should be graduated like the bar of a steelyard. 
 
 There are a few other parts of this dynamometer not 
 yet described. One is the cylinder o, filled with oil, in 
 which a perforated piston works, preventing the rapid 
 vibration of the lever », as the force varies, precisely 
 similar to the cylinder of oil described in fig. 110, p. 100. 
 Another part is the pendulum p, with the wheel r, which 
 measures the time. 
 
 The use of this instrument has been already attended 
 with some important results in detecting the great amount 
 of friction existing in some thrashing-machines of high 
 reputation, which has been found to amount, in certain 
 cases, to more than one-half of the whole power applied. 
 It is only by detecting so great a waste that we are ena- 
 bled to take measures for its prevention. 
 
 CHAPTER VIII. 
 
 APPLICATION OF LABOR. 
 
 Most of the moving powers applied by the farmer to 
 accomplish labor are the exertions of animal strength. A 
 principal object of the preceding pages is to point out how 
 this strength can be applied in the most economical 
 manner, and to aid in the substitution of cheap horse- 
 power for more costly human labor. It will doubtless 
 contribute to the end to exhibit the relative efficiency of 
 each, as well as the results of strength differently applied. 
 
 The amount of work which any machine is capable of 
 performing is denoted by comparing this amount with 
 
POWER OF HORSES. 109 
 
 the power of a single horse ; hence the common expres- 
 sions of twenty, or fifty, or a hundred horse-power 
 engines. The strength of different horses varies greatly, 
 but the expression, as commonly understood, indicates a 
 force equivalent to raising or pressing with a force equal 
 to 150 pounds 20 miles a day, at the rate of two and a 
 half miles an hour. This is the same as 33,000 pounds 
 raised one foot in one minute. The results of numerous 
 experiments in different places give the actual power of 
 the average of horses at somewhat less than this ; and 
 there is no doubt that, for most of the farm-horses of this 
 country, the result would be considerably less. The 
 power of a strong English draught-horse has been ascer- 
 tained to be about 143 pounds for 22 miles a day, at 2f 
 miles an hour. Many American horses are scarcely more 
 than half as strong. The strength of a man, working at 
 the best advantage, is estimated at one-fifth that of a 
 horse. 
 
 As the speed of a horse increases, his strength of draught 
 diminishes very rapidly, till at last he can move only his 
 own weight. This is owing to three reasons : first, the 
 load moves over a greater space in a given time, and if, 
 for instance, the speed be doubled, half the load only can 
 be carried with the same quantity of power, according to 
 the law of virtual velocities ; secondly, the horse has to 
 carry the full weight of his body, whatever his speed may 
 be, and the force expended for this purpose alone must, 
 therefore, be doubled as the speed is doubled ; thirdly, a 
 very quick and unaccustomed motion of the muscles is in 
 itself more fatiguing than the ordinary or natural velocity. 
 
 The following table shows the amount of labor a horse 
 of average strength is capable of performing in a day at 
 different degrees of speed, on canals, rail-roads, and on 
 turnpikes. The force of draught is estimated at about 83 
 pounds. This is considerably less than the horse-power 
 used in estimating the force of machinery, but it is as much 
 
110 MECHANICS. 
 
 as an ordinary horse can exert without being improperly- 
 fatigued with continued service : 
 
 Velocity 
 per hour. 
 
 Duration of the 
 day's work. 
 
 Hours. 
 
 Work accomplished for one day, 
 one mile. 
 
 in 
 
 tons, drawn 
 
 Miles. 
 
 On a canal. 
 
 On 
 
 a rail-road. 
 
 On 
 
 a turnpike. 
 
 2>li 
 
 H 1 1 3 
 
 520 
 
 
 115 
 
 
 U 
 
 3 
 
 8 
 
 243 
 
 
 9. 
 
 
 12 
 
 SMa 
 
 5 9 | 10 
 
 153 
 
 
 82 
 
 
 10 
 
 4 
 
 4^ 
 
 102 
 
 
 72 
 
 
 9 
 
 5 
 
 2*1x0 
 
 52 
 
 
 57 
 
 
 7.2 
 
 6 
 
 2 
 
 . 30 
 
 
 48 
 
 
 6 
 
 7 
 
 1M 2 
 
 19 
 
 
 41 
 
 
 5.1 
 
 8 
 
 l 1 Is 
 
 12.8 
 
 
 36 
 
 
 4.5 
 
 9 
 
 3 Ik 
 
 9 
 
 
 32 
 
 
 4 
 
 
 10 sj 4 6.6 28.8 3.6 
 
 From the preceding table it will be seen that a horse, at 
 a moderate walk, will do more than four times as much 
 work on a canal as on a rail-road ; but the resistance of 
 the water increases as the square of the velocity, and 
 therefore when the speed reaches five miles an hour, the 
 rail-road has the advantage of the canal. On the rail- 
 road and turnpike the resistance is about the same, 
 whether the speed be great or little, the chief loss with 
 fast driving resulting from the increased difficulty with 
 which the horse carries forward his own body, which 
 weighs from 800 to 1200 pounds. The table also shows 
 that when it becomes necessary to drive rapidly with a 
 load, it should be continued but for a very short space of 
 time ; for a horse becomes as much fatigued in an hour, 
 when drawing hard at ten miles an hour, as in twelve 
 hours at two and a half miles an hour ; because when a 
 boat is driven through the water, to double its velocity 
 not only requires that twice the amount of water should 
 be moved or displaced in a given time, but it must be 
 moved with twice the velocity, thus requiring a four-fold 
 force. 
 
 The muscular formation of a horse is such that he will 
 exert a considerably greater force when working horizon- 
 
POWER OP MEJf. Ill 
 
 tally than up a steep, inclined plane. On a level, a horse 
 is as strong as five men, but up a steep hill he is less strong 
 than three; for three men, carrying each 100 pounds, will 
 ascend faster than a horse with 300 pounds. Hence the 
 obvious waste of power in placing horses on steeply 
 inclined tread-wheels or aprons. The better mode is to 
 allow them to exert their force more nearly horizontally, 
 by being attached to a fixed portion of the machine. For 
 the same reason, the common opinion is erroneous that a 
 horse can draw with less fatigue on an undulating: than on 
 a level road, by the alternations of ascent and descent 
 calling different muscles into play, and relieving each in 
 turn ; for the same muscles are alike exerted on a level 
 and on an ascent, only in the latter case the fatigue is 
 much greater than the counterbalancing relief. Any per- 
 son may convince himself of the truth on* this subject by 
 first using a loaded wheel-barrow or hand-cart for one day 
 on a level, and for the next up and down a hill ; bearing 
 in mind, at the same time, that the human body is better 
 fitted for climbing and descending than that of a horse. 
 
 A draught-horse can draw 1600 pounds 23 miles in a 
 day, on a good common road, the weight of the carriage 
 included. On the best plank-road he will draw more 
 than twice as much. 
 
 A man of ordinary strength exerts a force of 30 pounds 
 for 10 hours a day, with a velocity of 2|- feet per second. 
 He travels, without a load, on level ground, during 8^- 
 hours a day, at the rate of 3.7 miles an hour, 31£ miles a 
 day. He can carry 111 pounds 11 miles a day. He can 
 carry in a wheel-barrow 150 pounds 10 miles a day. 
 
 Well-constructed machines for saving human labor by 
 means of horse-labor, when encumbered with little fric- 
 tion, will be found to do about five times as much work 
 for each horse as where the same work is performed by 
 an equal number of men. For example : an active man 
 will saw twice each stick of a cord of wood in a day. 
 
112 MECHANICS. 
 
 Six horses, with a circular saw, driven by means of a good 
 horse-power, will saw five times six, or thirty cords, work- 
 ing the same length of time. In this case the loss by 
 friction is about equal to the additional force required for 
 attendance on the machine. 
 
 Again : a man will cut with a cradle two acres of wheat 
 in a day. A two-horse reaper should therefore cut, at the 
 same rate, ten times two, or twenty acres. This has not 
 yet been accomplished. We may hence infer that the 
 machinery for reaping has been less perfected than for 
 sawing wood. It should, however, be remembered, that 
 great force is exerted, and for many hours in a day, in 
 cutting wheat with a cradle, and therefore less than 
 twenty acres a day may be regarded as the medium 
 attainment of good reaping-machines when they shall 
 become perfected. 
 
 Applying the same mode of estimate, a horse-cultivator 
 will do the work of five men with hoes, and a two-horse 
 plow the work of ten men with spades. A horse-rake 
 accomplishes more than five men, because human force is 
 not strongly exerted with the hand-rake. 
 
 In using different tools, the degree of force or pressure 
 applied to them varies greatly with the mode in which the 
 muscles are exerted. The following table gives the results 
 of experiments with human strength, variously applied, 
 for a short period : 
 
 Force of the hands Force of the tool 
 
 on the tool. on the object. 
 
 With a drawing-knife 100 lbs. 100 lbs. 
 
 " a large auger, both hands 100 " about 800 " 
 
 " a screw-driver, one hand 84 " 250 " 
 
 " a bench-vice handle 73 " about 1000 " 
 
 " a windlass, with one hand 60 " 180 to 700 " 
 
 " a hand-saw , 36 " 36 " 
 
 " a brace-bit, revolving 16 " 150 to 700 " 
 
 Twisting with thumb and fingers, but- 
 ton-screw, or small screw-driver 14 " 14 to 70 " 
 
 The force given in the last column will, of course, vary 
 
BEST WAY TO APPLY STRENGTH. 113 
 
 with the degree of leverage applied ; for example, the 
 arms of an auger, when of a given length, act with a 
 greater increase of power with a small size than with a 
 large one. This degree of power may be calculated for 
 an auger of any size, by considering the arms as a lever, 
 the centre screw the fulcrum, and the cutting-blade as the 
 weight to be moved. The same mode of estimate will 
 apply to the vice-handle, the windlass, and the brace-bit. 
 Every one is aware that a heavy weight, as a pail of 
 water, is easily lifted when the arm is extended downward, 
 but with extreme difficulty when thrown out horizontally. 
 In the latter case, the pail acts with a powerful leverage 
 on the elbow and shoulder-joint. For this reason, all 
 kinds of hand labor, with the arms pulling toward or 
 pushing directly from the shoulders, are most easily per- 
 formed, while a motion sidewise or at right angles to the 
 arm is fat less effective. Hence great strength is applied 
 in rowing a boat or in using a drawing-knife, and but little 
 strength in turning a brace-bit or working a dasher-churn. 
 Hence, too, the reason that, in turning a grindstone, the 
 pulling and thrusting part of the motion is more powerful 
 than that through the other parts of the revolution. 
 This also explains why two men, working at right 
 angles to each other on a windlass, can raise seventy 
 pounds more easily than one man can raise thirty 
 pounds alone. This principle should be well understood 
 in the construction or selection of all kinds of machines 
 for hand labor. 
 
 CHAPTER IX. 
 
 MODELS OF MACHINES. 
 
 Serious errors might often be avoided, and sometimes 
 gross impositions prevented, by understanding the differ- 
 ence between the working of a mere model, on a miniature 
 
114 MECHANICS. 
 
 scale, and the working of the full-sized machine. It is a 
 common and mistaken opinion that a well-constructed 
 model presents a perfect representation of the strength 
 and mode of operation of the machine itself. 
 
 When we enlarge the size of any thing, the strength of 
 each part is increased according to the square of the 
 diameter of that part ; that is, if the diameter is twice as 
 great, then the strength will be four times as great ; if the 
 diameter is increased three times, then the strength will 
 be nine times, and so on. But the weight increases at a 
 still greater rate than the strength, or according to the 
 cube of the diameter. Thus, if the diameter be doubled 
 (the shape being similar), the weight will be eight times 
 greater ; if it be tripled, the weight will be twenty-seven 
 times greater. Hence, the larger any part or machine is 
 made, the less able it becomes to support the still greater 
 increasing weight. If a model is made one-tenth the real 
 size intended, then its different parts, when enlarged to 
 full size, become one hundred times stronger, but they are 
 a thousand times heavier, and so are all the weights or 
 parts it has to sustain. All its parts would move ten 
 times faster, which, added to their thousand-fold weight, 
 would increase their inertia and momentum ten thousand 
 times. For this reason, a model will often work perfectly 
 when made on a small scale ; but when enlarged, the parts 
 become so much heavier, and their momentum so vastly 
 greater, from the longer sweep of motion, as to fail entirely 
 of success, or to become soon racked to pieces. 
 
 This same principle is illustrated in every part of the 
 works of creation. The large species of spiders spin 
 thicker webs, in comparison with their own diameter. 
 
 i 
 
 comparison 
 
 than those spun by the smaller ones. Enlarge a gnat 
 until its whole weight be equal to that of the eagle, and, 
 great as that enlargement would be, its wing will scarcely 
 have attained the thickness of writing-paper, and, instead 
 of supporting the weight of the animal, would bend down 
 

 WORKS OP CREATION FREE FROM MISTAKES. 115 
 
 from its own weight. The larger spiders rarely have legs 
 so slender in form as the smaller ones ; the form of the 
 Shetland pony is quite different from that of the large 
 cart-horse ; and the cart-horse has a slenderer form than 
 the elephant. 
 
 The common flea will leap two hundred times the length 
 of its own body, and the remark has been sometimes made 
 that a man equally agile, with his present size, Avould 
 vault over the highest city-steeple, or across a river as 
 wide as the Hudson at Albany. Now, if the flea were 
 increased in size to that of a man, it would become a 
 hundred thousand times stronger, but thirty million times 
 heavier ; that is, its weight would become three hundred 
 times greater than its corresponding strength. Hence we 
 may infer that the enlarged flea would be no more agile 
 than a man ; or that, if a man were proportionately 
 reduced to the size of a flea, he could leap to as great a 
 distance. 
 
 All this serves to illustrate in a striking manner the 
 great difference in the working of models and of machines. 
 
 CHAPTER X. 
 
 CONSTRUCTION AND USE OF FARM IMPLEMENTS AND MA- 
 CHINES IMPLEMENTS FOR TILLAGE. 
 
 The application of mechanical principles in the struc- 
 ture of the simpler parts of implements and machines has 
 been already treated of. It remains to examine more 
 particularly those machines chiefly important to the farmer, 
 and to show the application of these principles in their 
 use and operation. 
 
116 MECHANICS. 
 
 Farm implements and machines for working the soil 
 should be, as far as possible, simple and not complex, be- 
 cause they mostly meet with an irregular resistance, con- 
 sisting of hard and soft soil and stones variously mixed 
 together. A locomotive is made up of many parts ; but 
 having a smooth surface to traverse, the machinery works 
 uniformly and uninjured; but if in its progress it met 
 with formidable obstructions and uneven resistance, it 
 would be soon racked and beaten to pieces. Hence the 
 long-continued and uniform success of the simple plow ; 
 as well as the failure of complex digging machines, unless 
 worked exclusively in soils free from stone. A complex 
 machine, that meets with an occasional severe obstruction, 
 receives a blow like that of a sledge ; and when this is 
 repeated frequently, the probability is that some part will 
 be bent, twisted, knocked out of place, or broken. If the 
 machine be light, the chances are in its favor ; but il 
 heavy, its momentum is such that it can scarcely escape 
 severe injury. If composed of many distinct; parts, the 
 derangement or breakage of one of these is sufficient to 
 retard or put a stop to its working, and men and teams 
 must stand idle till the mischief is repaired. 
 
 Hence, after the trial of the multitude of implements 
 and machines, we fall back on those of the most simple 
 form, other things being equal. The crow-bar has been 
 employed from time immemorial, and it will not be likely 
 to go out of use in our day. For simplicity nothing ex- 
 ceeds it. Spades, hoes, forks, etc., are of a similar char- 
 acter. The plow, although made up of parts, becomes a 
 single thing when all are bolted and screwed together. 
 For this reason, with its moderate weight, it moves 
 through the soil with little difficulty — turning aside from 
 obstructions, on account of its wedge form, when it can- 
 not remove them. The harrow, although composed of 
 many pieces, becomes a fixed solid frame, moving on 
 through the soil as a single piece. So with the simpler 
 

 IMPORTANCE OF SIMPLICITY IX MACHINES. 117 
 
 cultivators. Contrast these with the ditching machine 
 (Pratt's) considerably used some years ago, but ending 
 in entire failure. It was ingeniously constructed and 
 well-made, and when new and every part uninjured, 
 worked admirably in some soils. But it was made 
 up of many parts, and weighed nearly half a ton. These 
 two facts fixed its doom. A complex machine, weighing 
 half a ton, moving three to five feet per second, could not 
 strike a large stone without a formidable jar ; and con- 
 tinued repetitions of such blows bent and deranged the 
 working parts. After using a while, these bent portions 
 retarded its working ; it must be frequently stopped, the 
 horses become badly fatigued, and all the machines were 
 finally thrown aside. This is a single example of what 
 must always occur with the use of heavy complex machinery 
 working in the soil. Mowing and reaping machines may 
 seem to be exceptions. But mowers and reapers do not 
 work in the soil or among stones ; but operate on a soft, 
 uniform, slightly resisting substance, made of the small 
 stems of plants. Every firmer knows what becomes of 
 them when they are repeatedly driven against obstruc- ' 
 tions by careless teamsters. 
 
 There is another formidable objection to complex ma- 
 chines — this is, their cost. Even with some of proved 
 value, the expense is a serious item with moderate farm- 
 ers. Mowers and reapers, $130; grain drills, $80 or $90; 
 thrashing machines, $100 to $400 ; horse rakes, $45 ; hay 
 tedders, $80 to $100 ; iron rollers, $50 to $100 ; and even 
 some of the efficient new potato diggers are offered for 
 not less than $100. Placing all these sums, and many 
 others for necessary tools together, the whole will be 
 found a large outlay — more economical by far, it is 
 true, than doing without them; but greater simplicity 
 and consequent cheapness, as well as durability, would 
 facilitate progress in agricultural improvement. A single 
 machine, Comstock's spader, is offered at $250 — twenty 
 
118 
 
 MECHANICS. 
 
 Fig. H6. 
 
 times the price of the best cast-iron plow, and ten times 
 that of the most finished steel plow. And yet it is ap- 
 plicable only to land free from stone. 
 
 The object of these remarks is to caution farmers against 
 investing money in 
 newly invented con- 
 trivances of high 
 promise at first, 
 which are liable to 
 the objection point- 
 ed out ; and also in- Kool ° plow - 
 ventors and manufacturers themselves against engaging in 
 enterprises having at hand golden promises, but with 
 failure in the distance. 
 
 PLOWS. 
 
 The simplest plow, used probably in the earlier ages of 
 the world, and found at the present day only among de- 
 graded nations, is the crooked limb of a tree, with a pro- 
 jecting point for tearing the surface of the earth. The 
 above figure represents an improvement on the first rude 
 implement, and is found at the present day in Northern 
 
 Fig. 117. 
 
 Moorish Plow. 
 
 India. Fig. 116 shows the Kooloo plow, consisting wholly 
 of wood, except the iron point. Fig. 117 exhibits the 
 implement now used in Morocco, which resembles the 
 India plows, with the addition of a rude piece of tim- 
 ber as a mould-board. Both these perform very imperfect 
 
PLOWS. 
 
 119 
 
 work, and have remained with little change for centuries, 
 the owners not enjoying the benefit of agricultural read- 
 
 rig. 118. 
 
 ing and intelligence. Fig. 118 is a step in advance, and 
 represents a plow still used in some parts of Europe. In 
 the less improved portions of Germany, the Baden plow, 
 
 Fig. na 
 
 Pig. 120. 
 
 Baden Plow. 
 represented by Fig. 119, is employed, and does not differ 
 greatly from the "bull plow" commonly used in this 
 country at the beginning of the 
 present century. Great im- 
 provement has been made within 
 the past fifty years, among others 
 by the ingenuity and labors of 
 Jethro Wood, and more recently 
 by a great number of inventors 
 and manufacturers in different 
 parts of the country. Wood 
 introduced the cast-iron plow 
 
 . . , t n i Modern Improved Ploiv. 
 
 into general and successiul use, 
 
 by cheapening its construction and perfecting its form, 
 
120 
 
 MECHANICS. 
 
 and others have made important improvements, including 
 the steel mould-board now largely employed at the West. 
 Cast-iron plows have been generally used throughout 
 the Eastern States ; but for the peculiar soil of the West, 
 it has been found absolutely necessary to use steel plows 
 exclusively ; and for the purpose of keeping them at all 
 
 Fiff. 121. 
 
 Moline Plow. 
 
 times sharp for cutting the vegetable fibre and separating 
 the parts of the soil readily, the practice is common to 
 carry a large file or rasp for this purpose. These steel 
 plows are made of plate previously rolled. They are be- 
 coming partially introduced also at the East, although in 
 hard and gravelly soils the cast-iron mould-board is pre- 
 ferred by many, and Fig. 122. 
 regarded as even 
 more durable. The 
 steel plate plow is 
 lighter than the cast- 
 iron, but is more 
 expensive. The ac- 
 companying figure Woodruff &, Allen's Steek-gkna. 
 (Fig. 121,) represents the celebrated "Moline plow," made 
 by Deere & Co., of Moline, 111., one of the best and most 
 extensively introduced among the Western steel imple- 
 ments ; and Fig. 122 shows an excellent one of Eastern 
 manufacture, made by Woodruff, Allen & Co., of Auburn, 
 

 CHARACTER OF A GOOD PLOW. 121 
 
 N". Y. Good steel plows cost about double those made 
 of cast-iron. 
 
 CHARACTER OF A GOOD PLOW. 
 
 Every good plow should possess two important quali- 
 ties. The first relates to its working. It should be easily 
 drawn through the soil, and run with uniform depth and 
 steadiness. The second refers to the character of the work 
 when completed. The inversion of the sod, especially if 
 encumbered with vegetable growth, should be complete 
 and perfect ; and the mass of earth thus inverted should 
 be left as thoroughly pulverized as practicable, instead of 
 being laid over in a solid, unmoved mass. This is of the 
 greatest importance on heavy soils, and is highly useful 
 on those of a lighter character, except, it may be, clear sand 
 or the lightest gravels. The harrow, at best, is an imper- 
 fect loosener ; it pulverizes the surface, but its weight, and 
 that of the team, press down the mass below. Whatever 
 loosening, therefore, can be accomplished in plowing is a 
 gain of vital importance. 
 
 THE CUTTING EDGE. 
 
 The point and cutting edge of the plow perform the first 
 work in separating the furrow-slice from the land. It is 
 important that this edge should not only do the work well, 
 but with the greatest possible ease to the team. The force 
 required to perform this cutting is greater than many sup- 
 pose. The gardener who thrusts his sharp spade into the 
 hard earth uses more force than afterwards in lifting and 
 inverting the spit. We may hence infer that a large part 
 of the power of the team is expended in severing the fur- 
 row-slice. This inference has been proved correct by the 
 use of the dynamometer, in connection with carefully con-? 
 (lucted experiments, which have shown the force usually 
 
122 
 
 MECHANICS. 
 
 expended for cutting off the side and bottom of the furrow- 
 slice, in firm soils, to exceed all the rest of the force re- 
 quired to draw the plow. The point or share should 
 therefore be kept sharp, and form as acute an angle as 
 practicable, as shown in Fig. 123. Some plows which other- 
 
 Fig. 123. 
 
 Fig. 124. 
 
 Fig. 125. 
 
 Fig. 126. 
 
 wise work well arc hard to draw because the edge, being 
 made too thick or obtuse, raises the earth abruptly. 
 Fig. 124. 
 
 Where stones or other obstructions exist in the soil, it is 
 important that the line of the cutting edge form an acute 
 angle with the land-side, or, 
 in other words, that it form a 
 sharp wedge, (Fig. 125.) It 
 will then crowd these obstruc- 
 tions aside, and pass them 
 with greater ease than when formed more 
 obtuse, as shown in Fig. 12G, for the same 
 reason that a sharp boat moves more freely 
 through the water than one which is blunt 
 or obtuse. The gardener or ditcher proves 
 
 this advantage when he thrusts a sharj> 
 pointed shovel, Fig. 127, more easily through 
 stony or gravelly soil, than one with a square 
 edge. (Fig. 128.) 
 
 But when the soil is free from stones, or 
 obstructions, or is filled with small roots 
 which the plow should cut off, as in the 
 Western prairies, the sharpness of the edge 
 is more important than its form ; and hence 
 the reason that the use of the rasp or file becomes neces- 
 
THE CUTTING EDGE. 123 
 
 saryin the field, to keep a sharp cutting edge at all times 
 on the share. 
 
 Note. — It has been shown in the Keport of the Trial of Plows at Utica, 
 that so far as yet determined by experiment in England, about thirty-five 
 per cent of the whole required draught is expended in overcoming the 
 friction of the implement on its bottom and sides, about fifty-five for 
 cutting the furrow-slice, and only about ten per cent for turning the 
 sod. Hence the exclusive attention formerly given to forming the 
 mould-board, as a means of reducing the draught, should have been 
 directed more to lessening the force required for cutting the hard soil. 
 
 These experiments, however, do not appear to have been entirely 
 satisfactory, especially for the light plows of this country; and it may 
 be interesting to test their accuracy by calculation. The average weight 
 of hard earth is about 125 lbs. per cubic foot; and the average draught 
 of plows at the trial near Albany in 1850 was about 400 lbs. for a furrow- 
 slice a foot wide and six inches deep. If a team in turning such sod 
 moves two miles an hour, it raises a slice three feet long, equal to a 
 cubic foot and a half (weighing 187 lbs.,) six inches each second— which 
 would be the same as raising 31 lbs. three feet per second, which is the 
 velocity of the plow. The mere force required to turn the sod, not esti- 
 mating friction, would therefore be only one-thirteenth of the 400 lbs. of 
 draught force. But the friction of dry earth on smooth iron is never 
 less than one-half its weight ; and if the earth is slightly plastic, its 
 friction often is equal to, and sometimes exceeds, its weight. Taking 
 the smallest amount, the friction on the mould-board would be equal to 
 half the weight of the portion of sod resting on the mould-board, or 
 about 31 lbs. This increased weight would also add equally to the fric- 
 tion of the sole of the plow, or 31 lbs. more— making the whole friction 
 62 lbs. ; which added to the weight of the sod would amount to 93 lbs. 
 —or more than one-fifth of the whole draught. 
 
 To ascertain the amount of friction, suppose the plow weighs 100 lbs. 
 Half its weight would be 50 lbs., the friction on the sole of the plow. 
 The friction of the sides would vary greatly with plows, being very 
 small with those having a perfect centre-draught, or with no tendency 
 to press against the land on the left. The whole friction and force for 
 lifting the sod would therefore be about 150 lbs. ; leaving 250 lbs. as the 
 force for cutting the slice. A very easy running plow would leave a 
 much smaller force— some as low as 200 lbs. 
 
 This estimate is liable to great variation. A wet and clayey soil would 
 double the friction ; a very hard piece of ground would add much to 
 the force required for cutting the slice ; if loose, the force would be com- 
 paratively small; or if quite moist, this force would be also much dim- 
 ished ; while the great difference in the draught of plows would vary the 
 results still farther. The estimate, however, for soil dry enough to be 
 friable, and of medium tenacity, is probably not far from correct, for 
 plowing in this country— showing that most of the force required is for 
 
124 
 
 MECHANICS. 
 
 the act of cutting', and indicating the importance of giving special at- 
 tention to the cutting edge. 
 
 THE MOULD-BOARD. 
 
 A prominent difference between good and bad plows 
 results from the form of the mould-board. To un- 
 derstand the best form, it must be observed that the slice 
 is first cut by the forward edge of the plow, and then one 
 side is gradually raised until it is turned completely over, 
 or bottom side up. To do this, the mould-board must 
 combine the two properties of the wedge and the screw. 
 
 The position of the furrow-slice, from the time it is first 
 cut until completely inverted, may be represented by 
 placing a leather strap flat upon a table, and then, while 
 
 Fiff. 129. 
 
 holding one end, turning over the other, so as to bring 
 that also flat upon the table, as in Fig. 129. 
 
 Now, if the sole object were merely to invert the sod, 
 the mould-board might have just such a shape as to fit 
 the furrow-slice while in the act Fig. 130. 
 
 of turning over, or resemble pre- 
 cisely the twist of this leather strap. 
 All the parts of this screw will be 
 found to fit a straight-edge, if 
 measured across at right angles, as indicated by the dot- 
 ted lines in Fig. 130. 
 
 But there are two objections to this form in practice. 
 The first is that the sod is laid over smoothly and un- 
 broken, and without being at all pulverized. On heavy and 
 hard soils this is a serious fault. The other objection is 
 that the sod is elevated as rapidly at the first movement, 
 when its weight is considerable, as just before falling, 
 when its pressure on the mould-board is slight. These diffi- 
 culties are in part removed by giving the mould-board a 
 
THE MOULD-BOARD. 125 
 
 shorter twist towards its rear. This form is distinctly 
 shown in the figure of Holbrook's Stubble Plow, on 
 a future page ; and it contributes largely to that crumbling 
 movement of the sod, so important for effecting pulveriza- 
 tion. 
 
 The mould-board of a plow is capable of an almost infi- 
 nite variety of forms, and the multitude of inventors have 
 each adopted a different one. Some have made their 
 selections by repeated random trials ; while others, among 
 whom Thomas Jefferson was the first, devised a series of 
 straight lines, mathematically arranged, by which uniform- 
 ity was given to the shape. The limits of this work pre- 
 clude a full explanation. Many modifications in com- 
 bining lines have been adopted, the most successful of 
 which is that of Ex-Governor Holbrook, of Vermont, 
 whose plows made according to these rules have perform- 
 ed admirably. It is less essential that farmers generally 
 should understand these mathematical principles, provided 
 they find a plow that will do good work ; because, as al- 
 ready shown, the form of the mould-board has compara- 
 tively little to do with the required draught of the team. 
 Fi~ 1.31 ^ w *^ ^e rea dily understood, however, 
 
 that more force will be needed for draw- 
 ing a short or blunt ])low, like Fig. 131, 
 than one in the form of a longer wedge, 
 as in fig. 132, the latter, like a sharp 
 boat in water, moving more easily. Care 
 must be taken, however, that this slender wedge be not 
 too long, else the friction of the sod on the extended sur- 
 face may overbalance the advantage. Fi(r 133 
 The cutting part of the plow may be 
 improperly formed like the square end 
 of a chisel, and the sod may slide back- 
 ward on a rise, with a very slight turn, 
 until elevated to a considerable height before inversion ; this 
 must require more force of the team, and make the plow hard 
 
126 
 
 MECHANICS. 
 
 Fig. 133. 
 
 to hold, on account of the side pressure. The character of 
 this kind of plow may be quickly perceived by simply ex- 
 amining the mould-board after use ; the scratches, instead 
 of passing around horizontally, as they should do, are seen 
 to shoot upward across the face and disappear at the top. 
 
 Instead of this form, the point should be long and acute, 
 and the mould-board so shaped as to begin to raise the 
 
 left side of the sod 
 the moment it is cut, 
 and before the right 
 side is yet reached 
 by the cutting edge. 
 This turning: motion 
 being continued, the 
 Ilolbroolc' s Stubble Plow, or Deep Tiller. S0( J j g inverted bv be- 
 
 ing scarcely lifted from its bed ; and the pressure which 
 turns it being opposite to the pressure of the land-side, an 
 equilibrium of these two pressures is maintained, and the 
 plowman is not compelled to bear constantly to the right 
 to keep the plow in its place. 
 
 There is, however, an exception, in deep or trench plow- 
 ing, where it becomes necessary to throw the earth from 
 the bottom of a furrow to the top of the inverted sod. A 
 plow of this kind is represented in Fig. 133, which shows 
 Holbrook's deep tiller for stubble land, capable of plowing 
 
 a furrow a foot deep, and 
 elevating the earth, which 
 passes lengthwise over the 
 mould-board. A similar 
 Crested Furrow-dicer. f orm mus t be adopted for 
 
 the rear mould-board of the Double Michigan Plow, so 
 that the lower earth of the furrow may be thrown on 
 the sod inverted by the first or skim-plow. 
 
 The share should also be so placed as to cut the slice 
 at equal thicknesses on both sides. Some plows are made 
 
 Fi<r. 134. 
 
CRESTED FUItEOW SLICES. 
 
 127 
 
 so as to cut deepest on the land-side, forming a sort of saw- 
 teeth section to the unmoved earth below, and leavino- 
 what is termed crested or acute ridges at the top. (Fig. 
 134.) Such plowing requires as much force in cutting the 
 slice, and nearly Fig. 135. 
 
 as much in turn- 
 ing it over, as 
 when level fur- 
 rows are made, 
 and should there- 
 fore be avoided. 
 The same result . 
 
 is produced when ^ ie ^ rai 9^ Cutter, Laying Lapped Furrows. 
 
 the plow is improperly gauged, and the plowman is com- 
 pelled to press the handles to the left, to keep it from 
 running too much to land. 
 
 On heavy or clay soils, it is sometimes desirable to place 
 inverted sod in an inclined or lapping position, in order to 
 give more exposure to the crumbling action of the weath- 
 er, and to effect better drainage beneath. Fig. 135 is a 
 section of these lapped furrows. In order to be equally in- 
 clined on both sides, their thickness must be precisely two- 
 thirds their breadth ; that is, if the plow runs eight inches 
 deep, the slices should be twelve 
 inches wide. This mode of plow- 
 ing is controlled by the position 
 of the cutter, which should be 
 very nearly upright, as shown in 
 Fig. 135. It has been justly re- 
 marked that the cutter to a plow 
 (Fig. 136,) is almost as important 
 as the rudder to a ship, and if 
 its position be altered, as shown in The CuUer. 
 
 Fig. 137, so as to cut under the sod, the furrows will cease 
 to be lapped and will lie flat. This position is desirable 
 in light or loose soils where exposure to the action of the 
 
128 
 
 MECHANICS. 
 
 air is not desirable, and where it becomes more important 
 
 to bury com- 
 pletely all veg- 
 etable growth 
 on the surface. 
 If furrows are 
 cut wider in 
 proportion to 
 their depth, 
 
 The Inclined Cutter, Laying Flat Furroivs. they will be 
 
 more likely to be laid flat. For example, if the plowing 
 is six inches deep, and the furrows are a foot wide, the 
 sod will generally dispose itself in a horizontal or flat 
 position, and this result will be the more certainly secured 
 by giving the form to the cutter already described. Lap- 
 ping the furrows is the common practice in England, but 
 is less necessary for this country, where the moisture of 
 rains dries more quickly, and the severer frosts effect a 
 ready pulverization ; and especially is the practice less 
 needed in thoroughly drained land. 
 
 The Committee for the trial of implements, appointed 
 by the New York State Agricultural Society, enumerated 
 the following desirable qualities in plows, which every 
 farmer may find useful to examine when he is about to 
 purchase. 1. Pulverizing power. 2. Non-liability to 
 choke in stubble. 3. Lightness of draught, considered in 
 connection with pulverizing juower. 4. Ease of holding. 
 5. Durability. 6. Cheapness. 7. Excellence of mechani- 
 cal work. 8. Excellence of material. 9. Thorough inver- 
 sion and burial of weeds. 10. Even distribution of wear. 
 11. Regularity or trueness of turning and carrying the 
 furrow-slice in sod. 
 
 OPERATION OF PLOWING. 
 
 The expert plowman so adjusts his implement that it 
 will cut a furrow r of just such width and thickness as 
 
OPERATION OF PLOWING. 129 
 
 may be done with the least draught to the team, and the 
 least exertion to himself. " To secure this end," says 
 Todd, " the team is hitched as close to the plow as it can 
 be and not have the whiffle-trees hit their heels in turn- 
 ing at the corners. As the length of the traces is in- 
 creased, in plowing, the draught increases. Now put the 
 connecting ring, or link, or dial clevis, at the end of the 
 beam, in the lowest notch ; and if it will not run deep 
 enough, raise it another notch at a time until it will run 
 just deep enough. Now alter the clevis from right to 
 left, or from left to right, as may be necessary, until the 
 plow will cut a furrow-slice just wide enough to turn it 
 over well. If the plow crowds the furrow-slice without 
 turning it over, it shows that the furrow-slice is too nar- 
 row for its depth; and the plow must be adjusted to cut 
 a wider slice. On the contrary, if the plowman is obliged 
 to constantly push the furrow-slice over with his foot, if 
 the ground he is plowing be very smooth and even, it 
 shows that there is an imperfection or fault somewhere. 
 Sometimes by adjusting a plow to run an inch deeper, it 
 will do very bad work. And sometimes it is necessary to 
 adjust it to cut a little wider, or a little narrower, before 
 it will cut the furrow-slice as \\ r ell as it ought to be cut. 
 When a good plow is correctly adjusted, it will glide 
 along, where there are no obstructions, without being 
 held, for many rods. When a j)low is constantly inclined 
 to fall over either way, and the plowman must hold it up 
 all the while, to keep it erect, there is either an imperfec- 
 tion in the construction of the plow, or it is not adjusted 
 correctly. When a plow " tips up behind" and does not 
 keep down flat on its sole, or when it seems to run all on 
 the point, either the point is too blunt, or is worn off too 
 much on the under side, or there is not " dip enough " — 
 pitching of the plow downwards — to the point. Some- 
 times I have found that a plow could not be adjusted by 
 the clevis so correctly as all the parts were arranged ; and 
 6* 
 
130 MECHANICS. 
 
 that by shortening the traces or draught chain, or giving 
 them a little more length, it would run like another plow. 
 When a plow is adjusted to run just right, as the point 
 wears off it is necessary many times to give a little more 
 length to the draught chains, or to adjust it with the 
 clevis to run a little deeper. It is sometimes impossible 
 to adjust a plow to run just right with the style of clevis 
 which is on the end of the beam. The arrangement ought 
 always to be such that the draught can be adjusted half 
 an inch at a time, either up or down, or to the right or 
 left. Then if the beam of the plow stands as it should, so 
 that the most correct line of draught will cut the end of 
 the beam, it can be most correctly adjusted in a few 
 seconds. 
 
 " To make a plow run deeper, raise the connecting point 
 at the end of the beam one or more notches higher in the 
 clevis; or lengthen the draught chains. To make it run 
 more shallow, lower the draught a notch or more in the 
 clevis ; or shorten the draught chains ; or, which should 
 never be done, shorten the back-bands or hip-straps of the 
 harness. To make a plow take a wider furrow-slice, carry 
 the connecting point one or more notches in the clevis to 
 the right hand. A notch or two to the left hand will 
 make 'a plow cut a narrower furrow-slice. Or, which is 
 seldom allowable, a plow may be made to run more shal- 
 low by putting the gauge-wheel lower, so as to raise the 
 end of the beam. And a plow may be made to cut a nar- 
 rower furrow-slice by carrying the handles to the left 
 hand, or wider by carrying and holding them to the right, 
 beyond an erect position ; neither of which is allowable, 
 except for a temporary purpose." 
 
 PAST AND SLOW PLOWING. 
 
 It has already been shown in the chapter on Friction, 
 that the resistance is scarcely increased by velocity, when 
 one body slides over another. The same rule, nearly, ap- 
 

 FAST AND SLOW PLOWING. 131 
 
 pears to apply to force required for cutting the earth, 
 And as the friction of the plow and the force exerted in 
 cutting the earth have been found to be the greater 
 part of the whole draught, repeated experiments by the 
 dynamometer have proved that but little increased resist- 
 ance, as an average, occurs when a plow is drawn with in- 
 creased velocity; the only additional power being that of 
 doing more work in a given time. For example, if a force 
 of 400 lbs. be required to draw a plow, whether at two or 
 at four miles an hour, then twice as much power only is 
 needed to plow an hour at four miles, as at two miles per 
 hour. In other words, no more actual force in amount is 
 necessary in most instances for a team to plow an acre in 
 four hours at the faster speed than in eight hours at the 
 slower. Hence the importance on the score of economy 
 in time, of employing horses that have a naturally rapid 
 gait, provided they possess full strength to overcome the 
 required draught with ease. Fast plowing, however, is 
 better adapted to stubble land than sod. 
 
 THE DOUBLE MICHIGAN PLOW. 
 
 The Double Michigan, called also the sod and subsoil 
 plow, possesses some important advantages. The forward 
 or skim plow pares oif a sod a few inches in thickness, 
 and inverts it into the bottom of the previous furrow. 
 The second or main plow follows, and throws up the lower 
 soil, completely burying the inverted sod and giving a 
 loose, mellow surface to the field. This forms an excellent 
 preparation for all crops, particularly carrots and other 
 roots, which grow best in a deep, loose bed of earth ; and 
 where a portion of the subsoil improves the top-soil by be- 
 ing mixed with it, a permanent advantage results. A 
 greater depth may be attained by the use of this double 
 plow than with one having a single mould-board, in sod 
 ground, because the inversion will be complete even if the 
 
132 MECHANICS. 
 
 width of the furrow is only one-half the depth. But with 
 a single plow, the width must be considerably greater than 
 the depth, or the Fio , 138 
 
 sod will be thrown 
 on its side or edge 
 and cannot be in- 
 verted. There is 
 
 one disadvantage, 
 
 Double Michigan Plow. 
 however, m the 
 
 use of the double plow. A greater force is required 
 to make two cuts in the soil, one above the other, than 
 one cut with a single share.* For this reason more 
 force must be used to plow a field to a given depth, say 
 one foot, with the double than with the single plow. But 
 the single plow, in order to reach this depth, would re- 
 quire to be so large and to turn so wide a furrow that no 
 ordinary amount of team could be had to do the work. 
 And in addition to this difficulty the inverted surface would 
 not be so well pulverized as by the use of the double 
 plow. 
 
 THE SIDE-HILL PLOW. 
 
 Side-hill or Swivel plows are well known, and are so 
 constructed as to throw the furrow-slice down hill, which- 
 ever way the team may be passing. The mould-board is 
 turned to the right and left alternately for this purpose, 
 the right-hand horse walking in the furrow in one direc- 
 tion, and the left-hand horse in the other. This plow is 
 sometimes used for level land when it becomes desirable 
 to avoid dead furrows and ridges, "without plowing around 
 the field. Fig. 139 represents the swivel plow manufac- 
 
 * This result lias been proved by the use of the dyuamometer ; which 
 has also shown that a greater amount of earth, in cubic feet, may be 
 turned over with a deep-running plow than with a shallow one, as there 
 is less force expended in cutting the slice when compared with the whole 
 bulk — provided the soil is nearly uniform in hardness at different depths. 
 
THE SIDE-HILL PLOW. 
 
 133 
 
 Fig. 139. 
 Holbrook's Patent Swivel Plow. 
 
 tured by F. F. Holbrook & Co., Boston, one of the best 
 in use, and particu- 
 larly valuable for its 
 thorough pulveriza- 
 tion of the soil. One- 
 half of the double 
 mould-board shown 
 in the cut is used for 
 throwing the flllTOW Holbrookes Stvivel or Side-hUl Plow. 
 
 to the right, and the other half to the left — the change 
 being effected by passing it under the plow with a single 
 movement and hooking it in place. 
 
 THE SUBSOIL PLOW. 
 
 When the common two-horse plow alone is used by 
 farmers, it pulverizes the soil only a few inches in depth, 
 
 Fi<?. 140. 
 
 Subsoil plowing in the furrow of a common plow. 
 
 and its own weight and the tread of the horses on the 
 bottom of the furrow gradually form a hard crust at that 
 depth, through which the roots of plants and the moisture 
 of rains do not easily penetrate. Hence the roots have 
 only a few inches of good soil on the surface of the earth 
 for their support and nourishment ; and when heavy rains 
 fall, the shallow bed of mellow earth is soaked and injured 
 by surplus water. Again, in time of drought, this shal- 
 low bed of moisture is soon evaporated, and the plants 
 suffer in consequence. 
 
 But, on the other hand, when the soil is made deep, it 
 absorbs, like a sponge, all the rains that fall, and gradually 
 gives off the moisture as it is wanted during hot and dry 
 seasons. For this reason, deep soils are not so easily in- 
 
J 34 MECHANICS. 
 
 jured by excessive wetness, or by extreme drought, as 
 shallow ones. In addition to this advantage, they allow 
 a deeper range for the roots in search of nourishment. 
 
 Soils are deepened by trench-plowing and by subsoiling. 
 In trench-plowing, the common plow with a mould-board 
 is made to enter the earth to an unusual depth, and to 
 throw up a portion of the subsoil, covering with it the 
 top-soil which is thrown under. A subsoil plow, on the 
 contrary, only loosens the subsoil, but does not lift it to 
 the surface. 
 
 The Double Michigan Plow, just described, is strictly a 
 trench-plow, and is one of the best implements for this 
 purpose. 
 
 When the subsoil is of such a character that its mixture 
 with the surface tends to render the whole richer, trench- 
 plowing is best ; but when of a more sterile character, it 
 should be only loosened with the subsoil plow, and more 
 cautiously intermixed with the richer portion above. 
 
 It often happens that the subsoil plow is very useful in 
 loosening the soil for the purpose of allowing the trench- 
 plow to run more freely through it. 
 
 The operation of the subsoil plow is shown in fig. 140. 
 
 In using the subsoil plow the less the earth is raised, 
 provided it is well broken to pieces, the easier will be the 
 draught. The part which moves under the soil and per- 
 forms this loosening is of course in the form of a wedge. 
 If the subsoil is dry, hard, and not adhesive, a long and 
 acute wedge will run most easily ; but if the subsoil is 
 stony, a shorter wedge will succeed better. For general 
 purposes it should therefore be of medium length. 
 
 Different modes of connecting this wedge to the beam 
 above have been adopted, each possessing its peculiar ad- 
 vantages. Fig. 141 represents a subsoil plow with a 
 single, broad, upright shank, cutting like a wedge, with 
 
THE SUBSOIL TLOW 
 
 135 
 
 
 double edges as well as double points, and capable of be- 
 Fi »- 141 - ing reversed when 
 
 it becomes worn. 
 In light or grav- 
 elly soils this plow 
 runs well ; but 
 where the earth 
 adhesive and 
 
 is 
 
 Broad-shank SubsoUer. 
 
 rather moist, the 
 friction of the two faces of this shank in pressing the 
 
 Fig. 142. 
 
 -iC=«x^. 
 
 Subsoil plow. 
 
 compact soil apart becomes enormous, amounting in some 
 
 cases to more than triple the force required to loosen 
 
 Fig. 143. the soil below. 
 
 This plow is there- 
 fore not to be rec- 
 ommended for 
 general use. The 
 objection is in a 
 great measure ob- 
 viated in the plow 
 shown in fig. 142, 
 where the forward portion of the broad plate is made 
 thicker than the rest. The friction is still further less- 
 ened by employing two narrow shanks, as in fig. 143, 
 
 Another improvement for lessening friction might be 
 made by using narrow bars of iron or steel, braced and 
 
 Two-shanked Subsoiler. 
 
136 
 
 MECHANICS. 
 
 Fig. 144. 
 
 connected as shown in fig. 144. The ditching plow, 
 exhibited in fig. 147, is similar in the construction of 
 
 this part, and it 
 has been found 
 to work well 
 for subsoiling, 
 particularly in 
 stony land. If 
 the subsoil hap- 
 
 Brace-sJiank Subsoiler. pens to be filled 
 
 with roots, the interstices in these plows sometimes become 
 choked — a difficulty, however, which rarely occurs. In 
 such cases it may be better to employ the plow represented 
 by fig. 141. 
 
 New subsoil plows have been lately constructed at the 
 West, by which the operations of both plows are perform- 
 ed at once. A saving is thus made in the expense of the 
 implement and in the labor of one man. In one, known 
 as the Nichols' plow, a flat, triangular blade runs a few 
 inches below the common plow; in Wheatley's, a narrow 
 blade bent like the letter U beneath the plow performs 
 the work. 
 
 The benefit of subsoiling will last three or four years ; 
 but it is of great importance that land be well under- 
 drained, for if the earth becomes heavily soaked with wa- 
 ter, it settles down into one compact mass, and the advant- 
 ages of the operation are lost. 
 
 THE TAKING PLOW 
 
 consists merely of a flat blade, which runs beneath the 
 surface, shaving off the roots, but not moving the soil (fig. 
 145). A shield, shown in the cut, is placed beneath the 
 beam, to regulate the depth of the cutting blade. It is 
 used in cutting turf for burning, and for destroying this- 
 tles and other deep-rooted weeds. When made light for 
 a single horse, it is sometimes used advantageously for 
 
THE GANG PLOW. 
 
 13? 
 
 cutting the grass and weeds between rows of badly tilled 
 corn. A two-horse paring plow has been constructed, in 
 which the depth of cutting is accurately regulated by 
 wheels placed on an axle, like those of a cart. The cast- 
 
 Fisr. 145. 
 
 ^tsisz^Wi-UUVt*" 
 
 Paring plow. 
 
 iron blade, which cuts about three feet wide, is raised or 
 depressed by means of screws passing through the axle. 
 Its chief utility is in destroying grass and weeds before 
 the sowing of broadcast crops. 
 
 THE GANG PLOW 
 
 consists of three or four small mould-boards placed side 
 by side (fig. 146), and is used for shallow plowing, or for 
 
 Fi<r. 14G. 
 
 Gang plow. 
 
 burying manure or seed on inverted sod, without disturb- 
 
138 M'ECHAmCS. 
 
 ins; the turf beneath. In those of the best construction, 
 the depth is regulated by wheels, and the breadth of the 
 furrows by turning the cross-beam more or less obliquely, 
 by means of a fixed contrivance for this purpose. The 
 gang plow is liable to become impeded or clogged by 
 stubble, coarse manure, or weeds, and has not come into 
 extensive use. 
 
 DITCHING PLOWS. 
 
 In most localities where tile drains are made, two-thirds 
 of the labor of cutting is loosening the earth with the 
 pick, before shoveling it out. By means of the ditching 
 plow this laborious work is performed by horses. One 
 span, with a good plow made for this purpose, will loosen 
 the subsoil fast enough for eight or ten men shoveling, 
 and cutting about 100 rods 3 ft. deep in a day ; or an hour 
 M „ . or two each day with 
 
 Fig. 147. / 
 
 efSSS ^ the plow will keep 
 
 ..<y^^Z^=^ ^ w0 men a ^ wor ^« 
 
 ^""^^'ifr--^- J^^^^*^ ^ tne su ^ sou i s very 
 
 gj^ _ - t ^zL 1 ^--'' "t ^ SSST p hard, this work 
 
 /((K ^jKjr i'J should be done early 
 
 ^^ Jni Wsi^ ^ n summer. The 
 
 implement is drawn 
 by two horses, at- 
 tached to the ends of a main whiffle-tree about seven feet 
 long, one walking on each side of the ditch. From one 
 to three times passing will loosen the subsoil five to eight 
 inches, which is then thrown out by narrow shovels, on 
 both sides, so that it may be easily returned after the tile 
 is laid, by means of a common plow drawn by the long 
 whime-tree before mentioned. 
 
 There are several modifications of the ditching plow, all 
 accomplishing the same end. The adjustable ditching 
 ploio, (fig. 147,) admits of so great a change in the height 
 
 Adjustable Ditching rioic. 
 
DITCHING PLOWS. 139 
 
 of the beam and handles, that it may be run down in the 
 bottom of a ditch to a depth of four feet. It is, perhaps, 
 the best implement of the kind for all purposes and soils. 
 The movable portion of the beam is attached to the fixed 
 beam by a stout loop and staple, and rises on a cast-iron 
 arc, which passes through it, as shown by the dotted lines. 
 The handles rise on a stiff, wooden arc, (as the dotted lines 
 exhibit,) a piece of thick plank, shown in the small figure 
 on the right, being placed between the handles and fast- 
 ened to them, to render them more firm and steady. The 
 iron work, although light, is braced so as to impart great 
 strength and security. The point is screwed on separate- 
 ly, and is nearly the only part that wears by use. 
 
 This ditching plow may be used for common subsoiling, 
 the shortness of the share rendering it especially adapted 
 to stony land. 
 
 Several ditching machines have been constructed for 
 performing the entire operation of cutting the earth and 
 throwing it out, but nearly all of them are too complex 
 for common use. Except in land entirely free from stone, 
 some of their many parts are liable to become bent or in- 
 jured by use, and a very slight derangement of this kind 
 renders them partly or entirely useless. Any ditching 
 machine, therefore, to work well among stone, must be 
 simple and strong, so as to withstand the frequent shocks 
 met with in overcoming obstructions in the soil. 
 
 MOLE PLOW. 
 
 The Mole Plow has a wooden beam, sheathed with iron 
 on the lower side, which moves close to the ground, be- 
 low which a thin, broad coulter extends downward, and 
 to the lower end of this coulter a sharp iron cylinder is 
 attached. This moves horizontally, point foremost, through 
 the soil, producing a hollow channel beneath the plow for 
 the escape of the water, the only trace on the surface be- 
 
140 MECHANICS. 
 
 ing a narrow slit left by the coulter. It is dragged for- 
 ward by means of a chain and capstan worked by a horse, 
 the machine itself being fixed with strong iron anchors. 
 This mode of draining is only adapted to clay soil, free 
 from stone, and although cheaply performed, has been little 
 used since the introduction of tile-draining. 
 
 APPENDAGES TO THE PLOW. 
 
 Wheel Coulters. — In soils free from stones and coarse 
 gravel, and especially on the Western prairies, wheel 
 coulters are found to answer a good purpose, cutting 
 through the turf and roots of grass with great ease, and 
 making a smoother slice than the common cutter. But 
 where stones and other obstructions exist, it is necessary 
 to use the simpler, single blade coulter. A good repre- 
 sentation of the wheel coulter is seen on the figure of the 
 Moline Plow, on an early page of this chapter. 
 
 Weed-Hook axd Chaix. — In turning under large 
 weeds, grass, or other tall vegetable growth, two modes 
 are adopted. One is Fig. i^s. 
 
 the use of the weed 
 hook represented in 
 the annexed cut ; 
 and the other is that 
 of a chain. The 
 weed-hook has been 
 long known, and is 
 made in various Weed-hook. 
 
 forms. Sometimes it is bent in the form of a bow 
 with the lower point projecting forward, as in the upper 
 figure ; another form is like that shown in the lower cut, 
 pointing backwards. This is less liable to be caught by 
 obstructions. The weed-hook operates on the principle 
 of bending the tall growth forward and prostrate, so that 
 the turning sod completely buries it. The same object is 
 
WEED-HOOK AND CHAIN. 141 
 
 attained by the use of a heavy chain ; and different modes 
 are used for attaching it to the plow. One of the sim- 
 plest is to fasten one end to the right-hand portion of the 
 main whiffle-tree, and the other to the right handle. In 
 another mode, the chain forms a loop. All these modes 
 of burying vegetable growth are important in turning 
 under clover and other green crops. 
 
 The weed-hook is usually made of round rod-iron, stiff 
 enough to perform its work, and to possess some spring 
 when it meets with obstructions. Those not accustomed 
 to its use may adjust its position by bending it, until it 
 performs satisfactorily. It is secured to the plow-beam 
 by placing the forward end in a small groove cut length- 
 wise in the under side of the beam, passing a band over 
 it, and wedging until properly secured. Lighter and more 
 perfect weed-hooks may be made of steel rod, similar to 
 that used for rake teeth ; they will bend back on meet- 
 ing obstructions, and spring again into position. Such 
 weed-hooks should be made and sold with the other ap- 
 pendages of plows, now that the inversion of green clover 
 for manure has become an essential part of good farming. 
 Sometimes the weed-hook is made to extend at right 
 angles to the plow-beam, curving outwards and down- 
 wards. This form requires greater stiffness, and small bar- 
 iron is used. 
 
 No plow will cover weeds or other growth two or three 
 feet high ; but by the use of this hook, the whole is laid 
 completely under the surface. 
 
 Regulating Wheel. — It has long been a question witli 
 plow men whether the wheel under the beam for regula- 
 ting depth is really a disadvantage or a benefit. It is fully 
 shown in the able Report by J. Stanton Gould, of the Trial 
 of Plows at Utica, drawn from accurate experiments, that 
 the wheel not only gives better plowing with moderate 
 skill, but that it slightly lessens the draught. Uniformity 
 in the depth of the slice is preserved, without constant 
 
142 MECHANICS. 
 
 vigilance on the part of the attendant ; and this uniform- 
 ity, by preventing uneven running, lessens the aggregate 
 amount of draught. It is, however, quite important that 
 the wheel sustain little or no pressure ; for as soon as the 
 beam bears upon it, the line of draught becomes crooked 
 at the expense of the team. These facts were established 
 by careful experiments with the dynamometer. 
 
 PULVERIZERS. 
 
 The fine pulverization of the earth, for the ready ex- 
 tension of the roots of plants, for the action of air on the 
 soil, for the retention of moisture, and for the thorough in- 
 termixture of manure, is of great importance to the fanner. 
 It is but partially accomplished by the plow, which crum- 
 bles the soil only so far as may be done by the act of 
 turning it over. Hence additional implements are needed 
 for this purpose, among which are the harrow, the cultiva- 
 tor, and the clod-crusher. 
 
 HARROWS. 
 
 The JBrush-harroic, the original and rudest form of the 
 implement, and still used for covering grass seed, as often 
 made, is a poor implement. The 
 most projecting limbs are cut partly 
 off, that all may lie flat, but it often 
 happens that the projecting angles of 
 the larger branches plow into the 
 around and make deep furrows. This 
 
 Brush-harrow. n , , n . . 
 
 may be prevented by a caretul selec- 
 tion of the small tree which forms the brush, or still better 
 by constructing a simple rough plank frame, so that any 
 quantity of short brush may be placed between two pieces 
 of plank, to admit the tops of the brush to incline down- 
 wards and backwards, being held in place by a few spikes 
 or bolts. Fiff. 149. 
 
GEDDES AND SCOTCH HARROWS. 
 
 143 
 
 Geddes Harrow. 
 
 The Geddes Harrow is one of the best in use for rough or 
 uneven land. The teeth being situated considerably back 
 of the point of draught, its motion is even and steady, 
 
 and easy for the team. In conse- 
 quence of its wedge-form, it passes 
 obstructions more readily. The 
 center or draught-rod forms a set 
 of hinges, by which it becomes 
 adapted to uneven ground, or by 
 which it may be easily lifted to 
 discharge weeds, roots, or other 
 obstructions. Or it may be doubled 
 back, and carried easily in a wagon. 
 The accompanying figure (fig. 150) 
 renders its construction intelligible, 
 without further description. To jjrevent its 
 rising in the middle, as it has been found to do 
 when the draught traces are as short as easy 
 draught requires, the chain is attached to the 
 bar on each side, as shown in fig. 151. Ml 
 
 The Square Harrow admits of a larger number of teeth, 
 and when made in the best form, effects thorough pulveri- 
 zation on smooth land, free from obstructions. A modifi- 
 cation known as the Scotch Fig. 152. 
 harrow, represented in fig. 
 152, has forty teeth, inserted 
 in such a manner that each 
 tooth forms a separate track, 
 ? as shown by the dotted lines. 
 The hinges, as 111 all square 
 harrows, enable it to fit a 
 rolling or uneven surface, 
 and it may be folded for 
 carrying in a cart or wagon. Scotch or S( i uare harrow. 
 For the fine pulverization of a smooth surface, a still 
 greater number of teeth has been found to answer an 
 
144 
 
 MECHANICS. 
 
 excellent purpose, leaving the soil almost as smooth as a 
 garden bed. Tough and sound timber, only two inches 
 square, is used for the frame, and the teeth are five- 
 eighths of an inch square. 
 
 The Morgan Harrow is an improvement of the Scotch 
 implement, slots being made in the hinges, so that each of 
 the two portions is capable of playing freely up and 
 down, as the surface varies, and rendering the rear teeth 
 less liable to follow in the track of the preceding. The 
 draught-iron is made to slide on an iron arc, so that the 
 lines formed by the teeth are controlled at pleasure. It 
 is converted into a broadcast cultivator by inserting flat 
 teeth, the flat portion below being the same in width as 
 above, and pointing slightly forwards. These teeth pul- 
 verize the soil deeply and thoroughly. They are success- 
 fully used for digging potatoes, operating like a large 
 number of potato-hooks, drawn by horses. 
 
 The Norwegian Harrow (fig. 153) is a new machine for 
 
 Fiff. 153. 
 
 Norwegian Harrow, kept from clogging by two cylinders of teeth 
 playing into each other. 
 
 pulverizing the soil, which performs the work in a very 
 perfect manner, by turning up, instead of packing down, 
 the earth. Two rows of star-shaped tines play into each 
 other, and produce a complete self-cleaning action, pre- 
 venting clogging even in quite adhesive soils. Its com- 
 
SHARES HARROW. 
 
 145 
 
 
 Fi£.154. 
 
 plex character and cost have prevented its coming into 
 more general use. 
 
 Shares' Marrow (fig. 154) is the most perfect of all im- 
 plements for pulverizing the freshly inverted surface of 
 sward land, to a depth two or three times as great as the 
 common harrow can effect. The teeth being sharp, flat 
 
 blades, cut with great ef- 
 ficiency ; and as they slope 
 like a sled-runner, they pass 
 % over the sod, and instead of 
 tearing it up like the com- 
 mon harrow or gang-plow, 
 they tend to keep it down, 
 and in its place, while the upper surface of the sod is 
 sliced up and torn into a fine, mellow soil. The price of 
 Shares' harrow is about $20, but if furnished with steel 
 teeth, as it should be, it would cost more. 
 
 CULTIVATORS. 
 
 Shares' Harroio. 
 
 The Cultivator or Horse-hoe is used for loosening and 
 pulverizing the soil among drilled crops, and for cutting 
 and destroying weeds. A usual form is shown in fig. 155, 
 which represents 
 Holbrook's, one 
 of the best of its 
 kind. The wheel 
 in front regulates 
 the depth ; the 
 sides may be ex- 
 panded or con- 
 tracted sufficient- 
 ly to vary the 
 width from fifteen to thirty-six inches ; they are reversible, 
 so that the soil may be thrown from or towards the row ; 
 and the frame is high enough to prevent clqgging witfr 
 7 
 
 Holbrook's Horse-hoe or Cultivator. 
 
146 MECHANICS. 
 
 weeds, stubble, or manure. Various forms of teeth are 
 used, according to the nature of the work, and they are 
 made of steel or cast-iron. The steel teeth, represented 
 in fig. 152, are well adapted for cultivating the rows of 
 Indian corn and other hoed crops, where the soil is al- 
 
 Fig. 150. 
 
 Claw-toothed cultivator for hard ground. 
 
 ready moderately mellow. For harder soils, the teeth 
 should be in the form of claws, as shown in fig. 156, their 
 sharp, wedge-form points penetrating and loosening the 
 earth with comparative ease. An efficient cultivator is 
 made by using both kinds of teeth in the same implement, 
 placing the claws forward for breaking the hard earth, and 
 the broader teeth behind for stirring it. 
 
 Steel plates, with sharp or " duck-feet " edges screwed 
 at the lower ex- Fig. 157. 
 
 tremities of the 
 teeth, (fig. 157) 
 are useful for par- 
 ing or cutting the 
 roots of weeds; 
 and formed like 
 the mould-board of a plow, they are used for throwing the 
 mellow earth toward the row, or, when reversed, from it. 
 
 Aiders Thill Cultivator is furnished with fixed thills, 
 extending backwards from the handles. The whole im- 
 plement thus runs with remarkable steadiness and great 
 efficiency, and the driver, by bearing on the handles, 
 
GAKRETt's HORSE-HOE. 
 
 147 
 
 readily increases the depth of the teeth, or by bearing to 
 the right or left, guides it in the row. It is not capable 
 of being expanded and contracted in width. 
 
 Garretfs Horse-hoe, an English invention, is a modifi- 
 cation of the cultivator, and is used for cultivating car- 
 rots and other root-crops in drills, cleaning eight or ten 
 rows at once. It is furnished with sharp, horizontal 
 blades, which run beneath the surface, and shave off and 
 destroy all the weeds within an inch of the rows of young 
 plants. These rows, having been planted by means of a 
 drilling-machine, are straight, and perfectly parallel, and 
 the operator has only to watch one row, and guide the 
 blades for that row, the apparatus being so contrived 
 that the blades for the other rows shall run at the same 
 distance from them. 
 
 Fig. 158 represents an end view of this implement. It 
 exhibits the apparatus by which the length of the axle is 
 
 Fig. 158. 
 
 Garrett's Horse-hoe— End view. 
 
 altered to suit all kinds of planting ; by which each hoe 
 is kept independent of the others, so as to suit the ine- 
 qualities of the ground, and by which they can be set any 
 width, from seven inches to thirty. It shows the oblique 
 angle at which they run— this obliquity being easily al- 
 
148 MECHANICS. 
 
 tered to any desired degree : this is effected by a move- 
 ment of the upper handle, represented in the figure. By 
 the lower handle, the whole is accurately guided. It is 
 said that two men, one to lead the horse, and the other to 
 guide the implement, will dress ten acres of root-crops in 
 a single day, and that it has proved eminently a labor- 
 saving machine. It can be used only on smooth land, 
 free from stone. 
 
 TWO-HORSE CULTIVATORS 
 
 are made to run on two wheels, and the depth of the 
 teeth is regulated by raising or lowering the frame-work 
 that holds them. They have been much used for pulver- 
 izing the surface of inverted sod, and fitting it for the re- 
 ception of seed, but are likely to be superseded for this 
 purpose by Shares' harrow. Modified so as to pass the 
 two spaces between three rows of corn, they are known 
 as double cultivators, and have now come into use for cul- 
 tivating large fields, and are generally adopted for this 
 purpose at the West. They accomplish twice the work 
 of the single cultivator. They are of two kinds : those 
 called the sulky cultivators, being furnished with a seat 
 on which the driver rides, and the walking cultivators, 
 without seat, the attendant walking behind. The former 
 will accomplish more work in a day, with less fatigue to 
 the driver ; the walking cultivators are better suited to 
 rough, or sidling ground, and are cheaper. Many manu- 
 facturers make them of different forms, both at the West 
 and in some of the more eastern States. The best sulky 
 cultivators cost about $75. 
 
 comstock's rotary spader. 
 
 This new machine, which has been used to some extent 
 in the broad fields of the West, forks up the soil by means 
 of a series of revolving teeth. It is drawn by two or 
 four horses, according to its size and the strength of the 
 
comstock's rotary spader. 149 
 
 animals, the driver riding on a seat. Sometimes two ma- 
 chines are attached together, and both are driven by one 
 man. It is used only on land free from sod, such as corn, 
 or other stubble, and is not adapted to land containing 
 stones or rocks. 
 
 Its advantages are the following : Greater ease of 
 draught, when compared with the plow, the chief source 
 of friction being the thrusting of the teeth into the soil, 
 while the friction of the plow at the mould-board is usu- 
 ally equal to at least half the weight of the moving sod, 
 added to half the entire weight of both plow and sod, on 
 the sole in the bottom of the furrow, while more force is 
 required to cut with the edge of the share than with the 
 points of the rotary spader. Hence it is found to do 
 twice or three times as much work with the same team as 
 a plow. It does not form a hard crust in the bottom of 
 the furrow, like the plow; and it leaves friable soils pul- 
 verized ready for planting, without the use of the harrow. 
 
 There are some serious drawbacks to the general intro- 
 duction of this machine. Its cost exceeds ten times that 
 of a good steel plow, while its complexity renders it more 
 liable to strain or breakage, except in uniform and stone- 
 less soils. It cannot be used in wet seasons, and pulver- 
 izes such land only as is previously free from grass. It 
 may, however, prove valuable on extensive farms. 
 
 CLOD-CRUSHERS. 
 
 In clayey soils, clods are often formed in abundance 
 during the process of cultivation. These become very 
 hard in dry weather, and prevent the proper extension of 
 the fine roots of plants in search of nourishment, and also 
 the intermixture of manure with the soil, without which 
 it has been found that two-thirds, or even three-fourths, of 
 the value of manure is lost to growing crops. 
 
 Different modes of pulverizing the clods have been 
 
150 
 
 MECHANICS. 
 
 adopted. The simplest is the " drag-roller" represented 
 in fig. 159. It is made of a log, or portion of a hollow 
 tree, into which a common two-horse wagon tongue has 
 been fitted, by which it is dragged over the ground with- 
 out rolling, grinding to powder, in its progress, every clod 
 over which it passes. The greater the diameter of the 
 
 log, the less will 
 be the liability of 
 its clogging by 
 gathering the 
 clods before it. 
 It may also be 
 made of a half 
 Fig. 160 represents 
 
 Fig. 159. 
 
 Clod-crusher. 
 
 log, with the round side downward. 
 
 Fig. 100. 
 
 One-horse Clod-crusher. 
 
 Fig. 101. 
 
 a similar imple- 
 ment for one 
 horse ; this is used 
 for working be- 
 tween the rows 
 of corn in cloddy 
 ground. 
 
 The use of these simple implements, by reducing rough 
 
 fields to a condi- 
 tion as mellow as 
 ashes, has,in some 
 instances, been 
 the means of 
 doubling the crop. 
 It is necessary 
 that the soil be 
 dry when they 
 are used, to pre- 
 vent its packing 
 
 CrosskHVs Clod-crusher. together. 
 
 CrosskilVs Clod-crusher, first used in England, is a 
 more powerful and more costly implement (fig. 161). It 
 
CLOD-CRUSIIERS. 
 
 151 
 
 consists of about two dozen circular cast-iron disks, 
 placed loosely upon an axle, so as to revolve separately. 
 Their outer circumference is formed into teeth, which 
 crush and grind up the clods as they roll over the surface 
 of the field. Every alternate disk has a larger hole for 
 the axle, which causes it to rise and fall while turning 
 over, and thus prevent the disks from clogging. Fig. 162 
 represents this implement, as modified and manufactured 
 in this country. It is used only where heavy clay soils 
 prevail. 
 
 This clod-crusher can be used only where the ground 
 and the clods have become quite dry. Even then it packs 
 
 Fig. 162. 
 
 American Clod-crusher. 
 the soil, and if followed by a harrow, with scarifier teeth, 
 to loosen it again, it would prove an advantage. It is 
 only in certain seasons that it is most successfully em- 
 ployed, or when quite dry weather follows a wet spring. 
 As thorough tile-draining is generally adopted, it becomes 
 less necessary. 
 
 The best clod-crushers are sold for about $125. 
 
 THE ROLLER. 
 
 This implement, now in general use, is employed for 
 pressing in grass seed after sowing, for smoothing the sur- 
 face of new meadows early in spring, and for other similar 
 
152 
 
 MECHANICS. 
 
 purposes. On light soils, it is most valuable, and may be 
 used at nearly all times with safety. Heavy or clay soils 
 will be crusted and injured if rolled while wet. The 
 
 Fkr. 1G3. 
 
 Field Roller. 
 roller was formerly made of a single piece, or of a log of 
 wood dressed to a true cylinder ; but this scraped the 
 earth when turned to the right or left. A great improve- 
 ment was made by cutting the single roller into two 
 parts; and a still greater, by employing cast-iron, in sev- 
 eral sections, as shown in fig. 163. The cost of cast 
 rollers is about $85 to $100. 
 
 CHAPTER XI. 
 
 PLANTING AND SOWING-MACHINES. 
 
 Sowing-machines, for wheat and other grains, possess 
 great advantages over hand-sowing. All the seed being 
 deposited by them at a nearly uniform depth, and com- 
 pletely covered with earth, it vegetates and grows evenly, 
 and the plants are uniformly strong and vigorous. A 
 less quantity of seed is required, and the crop is heavier. 
 
 WHEAT DRILLS. 
 
 Several excellent grain drills are now manufactured and 
 sold in this country, having much similarity in external 
 appearance. One of the best and most widely known 
 
SOWING-MACHINES. 
 
 153 
 
 Fitf. 164. 
 
 is made by Bichford <& Huffman, of Maccdon, N. Y. It 
 is represented in 
 the accompany- 
 ing cut, showing 
 eight dropping 
 tubes. The mode 
 by which the 
 grain is dis- 
 charged from the 
 hopper down 
 
 these tubes is ex- 
 hibited in section in fig. 165 ; d being the interior of the 
 hopper, bb a revolving wheel, the projecting rims of which 
 form the bottom of the seed-holder ; 
 the axle at a causes this wheel to 
 revolve, and the small projections on 
 
 the interior of the 
 
 rim carry the seed 
 
 to c, where it drops 
 
 through an opening 
 
 in the plate which 
 
 forms the side of the 
 
 seed-holder. The 
 
 rapidity of discharge is perfectly con- 
 trolled by wheel-work, which causes the 
 axle a to revolve slowly or fast at pleasure. The 
 seed-holder is divided into two parts by the wheel 
 a b, as shown by cross section in figure 166 ; one 
 part, d, containing wheat, barley, and other medium- 
 sized grains, and the 
 other, c, for corn, peas, 
 and the larger seeds. 
 This figure shows the 
 opening in the side- 
 plates, through which the grain is discharged. As these 
 two divisions must be used on separate occasions, the 
 
 Cross-section of Seed- 
 holder. 
 
 Cross-section of Bis ■ 
 charger. 
 
 Sliding Reversible Bottom of Hopper. 
 
154 MECHANICS. 
 
 openings between them and the hopper are opened and 
 closed at pleasure by a sliding bottom, with a single 
 movement of the hand. This sliding bottom is shown in 
 fig. 167, and forms hoppers with sloping sides, down 
 which the grain passes freely. 
 
 The ends of the tubes, which are shod with steel, are 
 made to pass any desired depth into the mellowed soil, 
 and depositing the seed, it is immediately covered by the 
 falling earth, as the drill passes. This drill is furnished 
 with an attachment for sowing plaster, guano, or any 
 other concentrated manure, and also with a grass-seed 
 sower. 
 
 A great improvement has been made in the mode al- 
 ready described, of discharging the seed ; formerly, seed- 
 drills generally were furnished with a revolving cylinder, 
 in the surface of which small cavities were made, for car- 
 rying off and dropping measured portions of the grain ; 
 these often broke or crushed the seed, and were liable to 
 derangement. Others were furnished with circular, re- 
 volving brushes, for pressing the seed through holes in 
 the bottom of the hopper ; but this contrivance was im- 
 perfect, and the brushes were liable to wear out. In the 
 discharging apparatus of the drill just described, the 
 seeds are never crushed, and the whole being substantially 
 made of cast-iron, it may be run a lifetime. The best 
 grain drills are sold for $80 or $90. 
 
 seymoue's broadcast sower 
 
 is an excellent machine for sowing plaster, ashes, guano, 
 salt, or any other concentrated fertilizer, as well as com- 
 mon grain and grass seed. The disagreeable, and even 
 dangerous, as well as heavy and laborious work of sow- 
 ing these manures by hand renders such a machine de- 
 sirable on every farm. It is drawn by one horse, sows 
 
CORN PLANTERS. 
 
 155 
 
 ten feet wide, and the operator rides in a seat. Seymour's 
 Plaster Sower sows these fertilizers, whether wet or dry. 
 These machines are sold at about $70. 
 
 Fig. 1G3. 
 
 CORN PLANTERS. 
 
 Among the best one-horse corn planters, which make 
 one drill at a time, are Emery's, Harrington's, and Bil- 
 lings'. The last-named, is represented in the annexed cut. 
 It drops in hills, eleven inches apart in the row, or, if de- 
 sired, twenty-two 
 inches, the perfora- 
 tions in the slides 
 regulating the 
 
 number of grains. 
 It is so constructed 
 as to drop any 
 desired amount of 
 
 Billings' Com Planter. plaster, guano, 01" 
 
 other concentrated manure, without coming in contact with 
 the seed. This, and other one-horse drills, are well adapted 
 to planting fields of considerable size, for cultivating in 
 rows but one way. On a larger scale, two-horse drills 
 are employed. Wheat drills are often used for this pur- 
 pose, employing only two of the tubes. Another class of 
 corn planters, for planting in hills, the rows running both 
 ways, consist of hollow tubes, which contain the seed, 
 and which, by striking or pressing on the soil, drop and 
 cover a hill at one stroke. 
 
 TRUE S POTATO PLANTER. 
 
 For field culture, this implement has proved an import- 
 ant saver of hand labor. It is drawn by one horse, and 
 cuts, drops, and covers the potatoes at one operation. It 
 is usually employed, on ground which has been plowed 
 
156 MECHANICS. 
 
 and harrowed only, the driver forming the drills by the 
 eye, as the planting proceeds. Straighter rows may be 
 made by first marking the land with a good corn-marker, 
 and then employing a small boy to ride, directing him to 
 keep the horse on the line. The driver has then only to 
 
 Fig-. 1GX 
 
 Time's Potato Planter. 
 
 watch the working of the machine before him. If the 
 ground is rough, or rather dry, it is better to furrow the 
 land previously with a single horse, running the planter 
 in these furrows. 
 
 For using this machine successfully, the seed potatoes 
 must be previously assorted, so that those of nearly equal 
 size may be used at a time. It is common to assort them 
 into two sizes, which may be done in winter, or on rainy 
 days. Each potato passes the throat of the hopper sin- 
 gly ; and if one in a bushel happens to be too large, it 
 will choke the opening. After passing the hopper, each 
 potato is sliced into pieces of the desired size, which 
 then, one by one, drop down the hollow coulter, and are 
 buried. The throat of the hopper is readily contracted 
 or expanded, and adapted to any assorted size of seed. 
 One man, with a horse, will plant several acres in a day, 
 and if the ground be in good order, with nearly or quite 
 
HAND DRILLS AND SEED SOWEKS. 
 
 157 
 
 as much accuracy as by hand, and with more uniformity 
 of depth. 
 
 HAND DRILLS, OR SEED SOWERS. 
 
 These are 2Teut savers of labor for sowing the seeds of 
 ruta-bagas, carrots, 
 field beets, and 
 other farm root 
 crops, besides peas 
 and beans. One 
 of the best in use 
 is Harrington's, 
 represented by fig. 
 170, and made by 
 F. F. Holbrook & 
 
 Co., Boston. The Harrington's Hand Seed Soxver. 
 
 side chains mark the rows, and it makes its own drill 
 Ffc. 1-1. drops, and covers 
 
 the seed with ac- 
 curacy, at one 
 operation. It is 
 readily changed 
 to the hand culti- 
 vator, by remov- 
 ing the dropper, 
 and attaching the 
 Harrington's Hand Cvltivator, cultivator teeth, 
 
 shown in fig. 171. It then becomes a convenient imple- 
 ment for running between the rows, in small fields. 
 
158 
 
 MECHANICS. 
 
 CHAPTER XIL 
 
 MACHINES FOR HAYING AND HARVESTING. 
 
 MOWING AND REAPING MACHINES. 
 
 The cutting part of the mowers and reapers made at 
 the present day consists of a serrated blade, as shown by 
 
 Kniv 
 
 fig. 172, which passes through narrow slits in each of the 
 lingers, shown in fig. 173, forming, when thus united, 
 
 Fi<r. 17.3. 
 
 cutting 
 
 the 
 paratus, as 
 
 Cutter-bar. 
 
 Fisr. 174. 
 
 ap- 
 ex- 
 hibited in the an- 
 nexed figure, of 
 Wood's Mowing- 
 machine (figure 
 174). When the 
 machine is used, the motion of the wheels on wdiich it 
 runs is multiplied by 
 means of the cog- 
 wheels, imparting 
 quick vibrations, end- 
 wise, to this blade, 
 shearing oif the grass 
 smoothly as it ad- 
 vances through the 
 meadow, like a large 
 number of scissors 
 in exceedingly rapid 
 motion. Wood's Mower. 
 
 The finger-bar, the most important part, now adopted 
 
M0WEES A2sD EEAPEES. 
 
 159 
 
 in all mowing and reaping machines, was invented by 
 Henry Ogle, of Alnwick, England, in 1822, and his machine 
 was put in successful operation, after much experimenting, 
 by T. & J. Brown, of that place. But so strong was the prej- 
 udice of the working people against labor-saving machine- 
 ry, that they threatened to kill the manufacturers if they 
 persevered ; and the enterprise for a time was given up.* 
 The limits of this work permit only a brief notice of 
 some of the chief 
 points in mow- 
 ers and reapers ; 
 and a few ma- 
 chines are refer- 
 red to, out of a 
 large number of 
 kinds, which are % 
 made in the dif- 
 ferent States, ^ 
 and which have 
 
 proved them- The Kirby Machine as a Mower 
 
 selves worthy of the confidence of farmers. 
 
 n.tr. 170. 
 
 The operation of 
 mowing is shown in 
 fig. 175, which rep- 
 resents the Kirby 
 mower, one of the 
 best single -wheel 
 machines, cutting a 
 swath five feet 
 wide, as fast as the 
 horses advance. 
 Buckeye Mower with Folded Bar. Various contriv- 
 
 ances are adopted for lifting or folding the cutter-bar when 
 the machine is not in operation, or in passing from one field 
 
 * Woodcroft. 
 
160 
 
 MECHANICS. 
 
 to another. A neat and convenient form is used in the 
 Buckeye Mower, represented in the accompanying cut, 
 (fig. 176) where the bar is folded over in front of the 
 driver's feet. 
 
 In the mowing-machine, the cutting apparatus is nar- 
 Fig. 177. row, causing the 
 
 newly cut grass to 
 fall evenly behind it, 
 covering the whole 
 surface of the 
 ground. The reap- 
 in fr-machine is simi- 
 lar in construction, 
 with the addition of 
 a platform for hold- 
 Kirby Reaper, with Hand Bake. j n<T || ie <rrain as if. 
 
 falls, as shown in the annexed figure of the Kirby machine, 
 changed to a reaper (fig. 177). 
 
 This figure represents the reel, which is attached to, 
 and is worked by the machine, causing the grain, as it is 
 cut, to drop smoothly Fig. 17S. 
 
 upon the platform. 
 "When a sufficient 
 quantity has collected 
 there, it is swept off 
 by the hand rake, and 
 is afterwards bound in 
 a sheaf. The annexed 
 cut exhibits the Cayu- 
 ga Chief, (an excellent Cayuga Chief— Combined Mower and Reaper. 
 two-wheeled machine) as a reaper, in which the opera- 
 tion of hand-raking is distinctly represented. 
 
 SELF-F.AKING KEAPEES. 
 
 Mowing-machines need but one man for their man- 
 agement, who merely drives the horses that draw it. 
 
SELF-RAKING HEATERS. 
 
 161 
 
 Reapers, as usually made, require another man besides the 
 driver, to rake off the bunches of cut grain, which is se- 
 vere labor. Various self-raking contrivances have been 
 used to obviate this labor, several of which have been 
 made to do excellent work, and arc coming into general 
 use. 
 
 One of the first successful self-raking attachments to 
 the reaper was that used by Seymour & Morgan, of 
 Brockport, K Y. It was one of the kind which sweeps 
 across the platform, in the arc of a circle, delivering the 
 gavel at the side of the machine. The ordinary reel is 
 used with this class of rakes. An objection to them is, 
 that the grain is seized for throwing off at a point behind 
 the cutters. Owen Dorsey introduced an improvement in 
 the form of what are termed reel-rakes, which strike the 
 grain forward of the cutters. A series of sweeps or 
 beaters were employed, combined with one or more rakes, 
 the gavel being delivered from the platform at each cir- 
 cuit of the rake. At first, the horizontal motion of these 
 
 arms prevented the 
 driver from riding 
 on the machine. An 
 improvement was ef- 
 fected, so that the 
 arms and rakes, after 
 passing the platform, 
 were made to rise to 
 a nearly vertical posi- 
 tion, thus passing the 
 driver freely. The 
 
 Fie:. 179. 
 
 The Kirby Self-raJcer. 
 
 accompanying engraving, (fig. 179) representing the self- 
 raker used on the Kirby machine, shows the position of 
 the arms when in motion — one of them serving as a rake 
 at each revolution. There are several modifications of 
 this class of rakes, made by different inventors. Marsh's 
 machine consists of beaters and rakes combined, and de- 
 
162 
 
 MECHANICS. 
 
 livers one or more gavels at each revolution, according to 
 the number of rakes used at a time. Johnson's rake is 
 furnished with rake-heads for each of the arms, which are 
 so arranged as to dip low into the grain forward of the 
 cutters, and afterwards to rise in passing over the plat- 
 form. To discharge the grain, the driver uses a latch- 
 cord and lever, so that the path in which the rake travels 
 is changed by opening a switch or gate, permitting one of 
 the rakes to pass low enough to sweep the platform. The 
 Cayuga Chief, Buckeye, Hubbard, and other reapers, use 
 this self-raker. The JLirby machine employs a self-raking 
 attachment of its own, already represented in fig. 179. 
 Two or three of the arms, or beaters, at the option of the 
 driver, bring the grain on the platform ; the other one or 
 two carry the rake-head. The driver may throw off a 
 gavel, or two gavels, at each revolution; or the rake may 
 "be made to run continuously, at regular intervals, without 
 attention on the part of the driver. The arms, or rakes, 
 are so made as to be adjustable to the height of the grain. 
 The Dropper is a simple contrivance, (represented in 
 the annexed en- Fig. iso. 
 
 graving) consist- 
 ing of a light plat- 
 form, which holds 
 the grain until the 
 gavel is large 
 enough, when it 
 suddenly drops 
 and discharges it. 
 It is much used at 
 
 the West and al- Cayuga Chief with Dropper. 
 
 though hardly so perfect as some self-rakers, is preferred 
 by many farmers, the gavels being delivered behind the 
 machine, and thus keeping the binders up to their work, 
 in clearing the way for the next passage of the reaper. 
 
 ttlt/VMT- 
 
marsh's harvester. 
 
 163 
 
 BINDERS. 
 
 Several machines for binding grain have been invented, 
 possessing considerable merit, but so far they do not ap- 
 pear to be adapted to general introduction. 
 
 Marsh's Harvester, much used at the West, is so con- 
 structed, that two men may readily bind as fast as the 
 harvester does its work. The binders stand on a small 
 
 platform, furnished 
 with a guard or rail, 
 and the grain, as fast 
 as it is cut, is carried 
 up by an endless 
 apron to a platform, 
 where each man alter- 
 nately makes his 
 band, and receives 
 and binds his sheaf. 
 As they expend no 
 time in stooping, or 
 in passing from gavel to gavel, they are enabled to work 
 with ease and rapidity. The weight is only that of one 
 man more than on a hand-raker. 
 
 Headers are reaping-machines employed for cutting the 
 heads of wheat with a small portion of the straw, leaving 
 most of the straw standing. They are usually driven by 
 four horses, and are thrust forward ahead of the team. A 
 two-horse wagon, in addition, is driven along side, to re- 
 ceive from an endless apron the heads, as they are cut by 
 the reaper. They are only used on the extensive fields of 
 the West, and a difference of opinion prevails as to their 
 general value. 
 
 DURABILITY AND SELECTION. 
 
 Mowing and reaping-machines, being complex, or made 
 up of many parts, would soon be broken and destroyed, 
 
104 MECHANICS. 
 
 if the resistance they meet with were irregular and full of 
 obstructions, like those which the plow encounters. 
 Standing grain and grass present a soft and uniform re- 
 sistance, and hence, well-made machines will last several 
 years without much repair. The Report of the Auburn 
 trial of mowers and reapers gives five years as the aver- 
 age " lifetime " of these machines. Much will depend on 
 the amount of work performed in a season ; an extensive 
 farmer states, that he usually cuts about five hundred 
 acres with each machine before it needs renewing. Much, 
 also, depends on the care which the machines receive ; 
 such as keeping them always well sheltered from the 
 weather, and thoroughly cleaning every part, and care- 
 fully wiping the journals and bearings before they are laid 
 aside for the season. 
 
 In selecting mowers and reapers, there are several 
 points which the purchaser should carefully observe ; as, 
 for example — 1. Simplicity of construction. 2. Use of 
 best material for knives and other parts used in manufac- 
 ture. 3. Finish and perfection of gearing and running 
 parts. 4. Durability, as proved by use. 5. Ease of 
 draught. 6. Freedom from side draught. 7. Quality 
 of work. 8. Ease of management. 9. Convenience 
 and safety of driver. 10. Adaptation to uneven sur- 
 faces. A part of these points can be fully determined 
 only by thorough trial ; and it is always safest to 
 purchase of those manufacturers whose machines have 
 been long enough in general use to establish their char- 
 acter in these respects. Fortunately, there are many in 
 different parts of the country, who have secured a good 
 reputation, from whom machines, or parts for repairs, may 
 be obtained without sending long distances. The report 
 of the Auburn trial, in 1866, states, that out of twenty 
 different mowing-machines, which were tried on a rough 
 meadow, every one, with two exceptions, " did good 
 work, which would be acceptable to any farmer ; and the 
 
HAY TEDDERS. 
 
 1G5 
 
 appearance of the whole meadow, after it had been raked 
 over, was vastly better than the average hand mowing of 
 the best farmers in the State." Since that trial, a con- 
 tinued improvement in manufacture has been taking place, 
 and the machines are becoming more perfect. 
 
 The price of a good two-horse mowing-machine is 
 about $120 ; and of a combined mower and reaper, about 
 $170. 
 
 HAY TEDDIXG MACHEN~ES. 
 
 Machines for stirring up and turning the drying hay 
 have long since been known and used in England, and a 
 few were introduced into use in this country. But as 
 they were heavy and cumbersome, they never came into 
 common use. A 
 few years since, 
 Bullard'sHayTed- v 
 der was invented, 
 and has been wide- 
 ly used. It scatters 
 and turns the hay 
 with great rapidi- 
 ty, and consists of 
 several forks, held 
 nearly upright, but 
 worked by a com- 
 pound crank, so as 
 
 to scatter the hay 
 
 . ~ , . Billiard? s Hay Tedder. 
 
 in the rear ot the 
 
 machine. The close resemblance of the movement of 
 
 these forks to the energetic scratching of a lien presents 
 
 a ludicrous appearance to one who sees it for the first 
 
 time. The use of the tedder is found greatly to hasten 
 
 the drying process, especially on heavy meadows, and to 
 
 enable the farmer to secure his hay in so short a time as 
 
 frequently to avoid damaging storms. 
 
166 
 
 MECHANICS. 
 
 A new machine, remarkable for its simplicity and per- 
 fection of working, is the American Hay Tedder, made 
 by the Ames Plow Company, of Boston. It is repre- 
 Fjcr ls3 sented in the 
 
 accompanying 
 cut. It is furnish- 
 ed with sixteen 
 forks, attached 
 to a light reel in 
 such a manner 
 that they re- 
 volve rapidly, 
 with a rotary, 
 continuous, and uniform motion. It never clogs, may be 
 easily backed, and readily passes over ordinary obstruc- 
 tions, without any attention on the part of the driver. 
 
 Hay tedders should be used on the meadow about 
 three times a day, which will enable the farmer to cut his 
 crop in the morning, and draw it in the same day ; giving 
 him, also, more uniformly dried, and better hay. 
 The price of hay tedders varies from $75 to £100. 
 
 Tlie American Hay Tedder. 
 
 HOESE HAY-RAKES. 
 
 The simplest and original form of the horse-rake is 
 represented in fig. 184. It was made of a piece of strong 
 scantling, three inches square, tapering slightly toward 
 the ends, for the purpose of combining strength with 
 lightness, and in which were set horizontally about fif- 
 teen teeth, twenty-two inches long, and an inch by an 
 inch and three-fourths at the place of insertion, tapering 
 on the under side, with a slight upward turn at the 
 points, to prevent running into the ground. The two 
 outer teeth were cut off to about one-third their first 
 length, and draught-ropes attached. If these pieces were 
 
HORSE HAY-HAKES. 
 
 167 
 
 too short, the teeth were hard to guide ; if too long, the 
 rake was unloaded with difficulty. Handles served to guide 
 
 Fig. 184. 
 
 Simple Horse-rake. 
 
 the teeth, to lift the rake from the ground in avoiding ob- 
 structions, and to empty the accumulated hay. 
 
 In using this rake, the teeth were run flat upon the 
 ground, passing under, and collecting the hay. When 
 full, the horse was stopped, the handles thrown forward, 
 the rake emptied and lifted over the windrow thus formed. 
 The windrows, as in other horse-rakes, were made at 
 right angles to the path of the rake, each load being de- 
 posited opposite the last heap formed, in previously cross- 
 ing the meadow. A few hours' practice enabled any one 
 to use this rake without difficulty; the only skill required 
 was to keep the teeth under the hay, and above the 
 ground. 
 
 In addition to raking, this implement was employed for 
 sweeping the hay from the windrow, and drawing it to the 
 Istack. It was also useful for cleaning up the scattered 
 hay from the meadow, at the close of the work ; for rak- 
 ing grain-stubble, and for pulling and gathering peas. If 
 made of the toughest wood, and with the proper taper in 
 the main parts for lightness and strength, according to 
 the principles already pointed out in a previous chapter, 
 it was easily lifted, and its use not attended with severe 
 labor. 
 
1G8 
 
 MECHANICS. 
 
 This simple horse-rake has nearly gone out of use, and 
 yet, on account of its simplicity and cheapness, it is wor- 
 thy of being retained on small farms, and especially on 
 meadows with uneven surfaces. The cost need not be 
 more than three or four dollars. From twelve to fifteen 
 acres could be raked with it in a day. 
 
 The Revolving Horse-rake (fig. 185) was next generally 
 adopted, possessing the great advantage of unloading 
 
 Fi". 1S5. 
 
 Revolviyig Horse-rake. 
 
 without lifting the rake or stopping the horse. It has a 
 double row of teeth, pointing each way, which are brought 
 alternately into use as the rake makes a semi-revolution 
 at each forming windrow, in its onward progress. They 
 are kept flat upon the ground by the pressure of the 
 square frame on their points, beneath the handles ; but as 
 soon as a load of hay has collected, the handles are 
 slightly raised, throwing this frame backwards, oif the 
 points, and raising them enough for the forward row to 
 catch the earth. The continued motion of the horse 
 causes the teeth to rise and revolve, throwing the back- 
 ward teeth foremost, over the windrow. In this way, each 
 set of teeth is alternately brought into operation. The 
 cost of this rake is from $7 to $10, and twenty acres 
 or more could be raked with it in a day. 
 
 A further improvement has been made in the revolving 
 rake, by attaching it to a sulky, on which the operator 
 
REVOLVING HORSE-RAKES. 
 
 169 
 
 Fig. ISO. 
 
 Fig. 187. 
 
 rides, enabling him to do a larger amount of work with 
 less fatigue. There are several modifications, some of 
 
 which place the rake 
 in front of the sulky 
 wheels, and others, 
 in the rear. One of 
 the best and most 
 widely used is 
 " Warner's Sulky 
 Revolver," manu- 
 factured by Bly- 
 myer, Day & Co., of Mansfield, Ohio, and by others. It is 
 represented in the annexed cuts, fig. 186 showing it in 
 the operation of raking, and fig. 187, the same machine, 
 with the rake thrown 
 upon the wheels, for 
 driving: from field to 
 field. The head is 
 the same as the com- 
 mon revolving rake- 
 head — the teeth be- 
 ing tipped with mal- 
 leable iron. The 
 rake is operated by _ 
 means of a lever, at- 
 tached to a journal at the centre of the rake-head. By 
 means of cams, stop, and spring, the lever and head are 
 entirely at the will of the operator. A slight pressure, 
 equal to seven or eight pounds, on a lever, causes the 
 rake to revolve ; and it is also readily elevated for back- 
 ing, or for passing obstructions. 
 
 An important advantage of this rake is, its gathering 
 the hay free from gravel and earth ; also its cheapness 
 recommends it — the price being about $35. 
 
 8 
 
170 
 
 MECHANICS. 
 
 SPRING-TOOTH EAKE. 
 
 The original form of the spring-tooth rake is shown in 
 fig. 188. The teeth were made of stiff, elastic wire, on 
 
 the points of which 
 the rake ran, and 
 not on the flat 
 sides, as in those 
 already described. 
 They bent in pass- 
 ing an obstruction, 
 and sprung back 
 again to their place. 
 This rake was un- 
 loaded by simply 
 lifting the handles, 
 which was easily 
 done, the rake be- 
 
 Vprmj-tnth Horsc-rake. mg J^J^ and 
 
 about one-half the weight being sustained by the horse. 
 
 All the spring-tooth rakes made and used at the present 
 time are attached to wheels, and a seat is furnished for 
 the driver. There are many patented modifications, some 
 possessing advantages of greater simplicity, or ease of 
 management ; but all appear to be good and efficient 
 rakes, enabling the operator to gather about twenty-five 
 acres in a day. 
 
 Among the best of the spring-tooth rakes is that of 
 Hollingsworth, made by Wanzer & Cromwell, of Chicago, 
 and represented in the accompanying engraving. Each 
 tooth is separate, and may be readily replaced. As soon 
 as the rake is loaded with hay, the driver, by touching 
 the lever before him, drops it at the line of the windrow. 
 The cost is about $45, 
 
THE HAT-SWEEP. 
 
 Fisr. 180. 
 
 171 
 
 nollimjmoniC s Spring-tooth Bake. 
 THE HAY-SWEEP. 
 
 Where the hay is secured in stacks, or in hay-barns 
 situated contiguous to the meadow, the use of the hay- 
 sweep, in connection with the horse-fork, would probably 
 
 enable two or three 
 
 men, and two feoys, 
 
 with three horses, to 
 
 draw and pack away 
 
 thirty tons a day, or 
 
 more. The hay-sweep, 
 
 invented many years 
 
 Hay-Sweep. ago by W. R. Smith, 
 
 of Macedon, N". Y., is but little known. The accompanying 
 
 figures (190 and 191) exhibit its construction and use. It 
 
 is essentially a large, stout, coarse rake, with teeth pro- 
 
172 
 
 MECHANICS. 
 
 jecting both ways, like those of a common revolver ; a 
 horse is attached to each end, and a boy rides each horse. 
 A horse passes along each side of the windrow, and the two 
 
 Fisr. 191. 
 
 Hay-siveep in Operation. 
 thus draw this rake after them, scooping up the hay as 
 they go. When 500 pounds or more are collected, they 
 draw it at once to the stack, or barn, and the horses turn- 
 ing about at each end, causing the gates to make half a 
 circle, draw the teeth backward from the heap of hay, 
 and go empty for another load — the teeth on opposite 
 sides being thus used alternately. To pitch easily, the 
 back of each load must be left so as to be pitched first. 
 
 The dimensions should be about as follows : — Main 
 scantling, below, 4 by 5 inches, 10 feet long ; the one 
 above it, same length, 3 by 4 inches ; these are three feet 
 apart, connected by seven upright bars, 1 by 2 inches, and 3 
 feet long. The teeth are flat, lh by 4 inches, 5 feet long, 
 or projecting 2^ feet each way ; they are made tapering 
 to the ends, so as to run easily under the windrow. A 
 gate, swinging half way round on very stout hinges, is 
 hung to each end of this rake, and to these gates the 
 horses are attached. Each gate consists of two pieces of 
 scantling, 3 inches square, and 3 feet long, united by two 
 bars of wood, 1 by 2 inches, and a third, at the bottom, 3 
 inches square, and tapering upwarols, like a sled runner; 
 
HORSE HAY-FORKS. 
 
 173 
 
 these runners project a few inches beyond the gate. The 
 whiffle-trees are fastened a little above the middle of the 
 gate, and should be raised or lowered so as to be exactly- 
 adjusted. This machine may be made for $6 or $7. 
 
 In using, not a moment is lost in loading or unloading. 
 No person is needed in attendance, except the two small 
 boys that ride the. horses. If the horses walk three miles 
 an hour, and travel a quarter of a mile for each load, they 
 will draw 12 loads, or three tons an hour, or thirty tons 
 in ten hours, leaving the men wholly occupied in raising 
 the hay from the ground, by means of another horse, with 
 the pitchfork. 
 
 It will be obvious, that this rapid mode of securing hay 
 will enable the farmer to elude showers and storms, which 
 might otherwise prove a great damage. 
 
 HORSE HAT -FORKS. 
 
 Every farmer who has over pitched off from a wagon 
 in one day ten or twelve tons of hay 
 is aware that no labor on the farm 
 can be more fatiguing. The horse- 
 fork, in its various forms, which, to a 
 considerable extent, has been brought 
 into use, has afforded great relief, 
 severe labor being not only avoided, 
 but much greater expedition attained. 
 The effective force of a horse is, at 
 least, five times as great as that of a 
 stout man; and if half an hour is 
 usually required for him to unload a 
 ton of hay, then only six minutes 
 would be necessary to accomplish the 
 same result with horse-power. Actual 
 experiment very nearly accords with 
 this estimate. 
 
 Fin. 192. 
 
 Original, Horse-fork. 
 
 A simple form of the horse pitchfork was described in 
 
174 
 
 MECHANICS. 
 
 the Albany Cultivator, in 1848, from which a subscriber 
 in Bradford County, Pa., made the first used in that re- 
 gion. Some years later, he stated that there were at least 
 two hundred in use. The preceding figure represents 
 this simple and original fork. A is the head, twenty- 
 eight inches long, and two and a half inches square, made 
 of strong wood. A G is the handle, five and a half feet 
 
 long, mortised 
 into the head, 
 with an iron 
 clasp or band of 
 hoop iron fitting 
 over the head, 
 and extending 
 six inches up the 
 handle, secured 
 bv rivets. The 
 prongs of the 
 fork are made of 
 good steel, one- 
 half an inch 
 wide at the 
 head, twenty 
 inches long, and 
 eight inches 
 apart, with nuts to screw them up tight. Rivets are placed 
 on each side of the middle ones, to prevent the head from 
 splitting. The rope is attached to staples at the ends of 
 the head. The single rope D extends over a tackle-block, at- 
 tached to a rafter at the peak of the barn, about two feet 
 within the edge of the bay. The rope then passes down 
 to the bottom of the door-post, under another tackle- 
 block, and to the outside of the barn, where the working 
 horse is attached to it. A small rope or cord G is attached 
 to the end of the handle, by which it is kept level, as it 
 ascends over the mow. The cord is then slackened, and 
 
 Pitching Hay through a Window with Horse-power. 
 
gladding's hoese-foek. 
 
 175 
 
 the hay tilts the fork, discharging its load. The horse is 
 then backed up, ready for another fork load, the only labor 
 of the workman being to drive the fork into the hay and 
 keep the cord steady. An important advantage is gained, 
 besides the saving of time ; for the man on the load, being 
 relieved from the severe labor of pitching, is fresh and 
 vigorous for throwing on another load in the field. 
 
 The length of the handle made it difficult to use this fork 
 under low roofs, and an improvement was made by Glad- 
 ding, by which the head of the rake only was tilted, 
 leaving the handle in its horizontal position. A hinge- 
 joint is placed at the connection of the head and handle, 
 
 so that, at any 
 
 Gladding's Hay-fork, 
 
 moment, by a jerk 
 on the cord which 
 passes up a bore 
 in the handle, the 
 fork is dropped, as 
 shown in fig. 194, 
 and its load depos- 
 ited. This may be 
 done instantane- 
 ously, at the mo- 
 ment it happens to 
 
 be sw T ung to the most favorable spot. Its weight causes the 
 head to fly back of its own accord, and resume its former 
 position, ready for another forkful. The rope suspending 
 the fork should be fastened to the highest portion of one 
 of the rafters, over the mow, and a smooth board should 
 be placed, vertically, against the face of the mow, for the 
 hay to slide on as it ascends. By attaching this rope in 
 front of, and within a window, the hay is carried with 
 ease into the window, and thus lofts over sheds, carriage- 
 houses, etc., where the old horse-fork could not be used, 
 are filled by the use of Gladding 's improvement. This is 
 one of the best forks, adapted to all kinds of pitching, 
 
176 
 
 MECHANICS. 
 
 and has unloaded a ton of hay in about three minutes; 
 and over a beam twenty-two feet high, under a low rafter, 
 in about nine minutes. 
 
 In using horse forks, as already stated, their operation 
 is much facilitated by providing a board slide, to be 
 placed vertically against the face of the mow, or bay, on 
 which the hay moves upward. In pitching into a win- 
 dow, the bottom of this board slide should be placed out 
 a few feet from the building, and the top should rest on 
 the base of the window. When convenient, the back 
 end of the wagon load should be placed towards the win- 
 dow. There is no limit to the height at which the pitch- 
 ing may be easily performed — giving the use of the 
 horse-fork a great advantage over hand pitching ; and 
 barns, with high posts, may be built for the storage of 
 hay. 
 
 Other forms have been adopted for pitching under roofs, 
 by using shorter handles. One of the best is Palmer's 
 
 Fig. 195. Fi"r. 193. 
 
 Palmer's Fork, 
 
 Fork, made by Wheeler & Co., Albany, and Palmer & Co., 
 
DOUBLE FORKS. 
 
 177 
 
 Chicago, which is represented in the accompanying figures, 
 Fig. 197. Fig. 193. the right-hand one 
 
 showing its posi- 
 tion when ascend- 
 ing, loaded with 
 hay ; the left-hand, 
 with the knee-joint 
 brace contracted, 
 by jerking the cord 
 for emptying the 
 load. Still another, 
 known as Myers* 
 Elevator, is shown 
 in fig. 197, in its 
 
 Myers 1 Hay Elevator. position when lift- 
 
 ing the hay, and fig. 198, when dropping it. The head is 
 iron, and it is a strong and simple fork. 
 
 DOUBLE FORKS. 
 
 The double forks clasp the load of hay like the claws of 
 a bird. This class Fi s- 1CJ,J - 
 
 of forks may be 
 used for pitching 
 over a beam, with- 
 out a board facing. 
 They are better 
 adapted to pitch- 
 ing short straw, 
 especially those 
 which like Ray- 
 mond's,have sever- 
 al teeth ; but more 
 time is required for 
 thrusting in the 
 two forks than one. 
 One of the simplest is Beardslei/s Hay Elevator, (fig. 199) 
 8* 
 
178 
 
 MECHANICS. 
 
 which sufficiently explains itself. 
 
 Fi£. 200. 
 
 Raymond's Fork. 
 
 moneys Elevator, made by J. II. 
 Y., consists of two three-pronged 
 forks, connected together by a 
 hinge, (fig. 200) and is one of the 
 best double forks. Connected 
 with this fork is a ready con- 
 trivance for attaching it, in a 
 moment, to any rafter or beam. 
 The accompanying figure (fig. 
 201) represents the clamp by 
 which this attachment is effected, 
 and fig. 200 shows the elevator, 
 secured in position from two 
 points, with the forks opened, 
 when dropping their load. It is 
 raised and lowered by the double 
 ropes passing over the two fixed 
 pulleys, and the one on the 
 elevator — the horse moving twice 
 as fast as the load is raised. 
 Thus attached to two beams, the 
 
 The "Little Giant" 
 Fork resembles the 
 claws of a bird, and 
 has a fluted, tubu- 
 lar, cast head, the 
 single grasping- 
 tooth being double- 
 jointed, and per- 
 mitting it to enter 
 the grain freely. 
 On the movement 
 of the horse, it is 
 brought to its 
 place, grasping its 
 load firmly. ^ay- 
 Chapman, Clayville, N. 
 
 Fiff. 201. 
 
 Grappling Irons and Hoisting 
 TasMe. 
 
 load may be run hori- 
 
HARPOON FORKS. 
 
 179 
 
 zontally, as well as raised vertically, as more fully ex- 
 plained under the head of Stacking. By the single fasten- 
 ing? ( fi g- 201) the fork is only raised vertically. 
 
 HARPOON FORKS. 
 
 For pitching hay exclusively, or any material which 
 hangs well together, the harpoon forks do their work 
 more rapidly than any other, but they are not adapted to 
 
 Fig. 205. 
 
 Fig. 204. 
 
 Fig. 202. 
 
 Fig. 203. 
 
 Walker's Harpoon Fork. Sprout's Fork. 
 
 short straw. Walker's harpoon, made by Wheeler,Melick 
 & Co., Albany, is a straight bar of metal, appearing al- 
 most as simple as a crow-bar, (fig. 202. Its point is driven 
 into the hay as far as desired, when a movement at the han- 
 dle is made, which turns up the point at right angles, (fig. 
 203,) enabling it to lift a large quantity of hay. A modifica- 
 tion has spurs, which are thrown out on opposite sides. 
 The combined fork and knife invented by Kniffen & Har- 
 
180 MECHANICS. 
 
 rington, of Worcester, Mass., is an excellent hay-knife, 
 when folded, as in fig. 205, and an efficient elevator, when 
 opened, as in fig. 204. It is well adapted to the use of 
 farmers who have nothing but hay to pitch, and plenty of 
 room for the elevator to swing in. At the Auburn trial, 
 this fork discharged a load of hay weighing twenty-three 
 hundred pounds, over a beam, in two minutes. 
 
 The prices of horse-forks, of different kinds, vary from 
 $10 to $20. 
 
 HAY CARRIERS. 
 
 An inconvenience results from the fixed position of a 
 hay-fork, preventing the hay from being distributed over 
 different parts of a broad bay, except so far as it may be 
 swung to the right or left, and the load dropped at a sig- 
 nal. Several hands are sometimes required to spread this 
 hay evenly, as it is rapidly discharged by the horse-fork. 
 Another disadvantage is, the required narrowness of the 
 bay, which cannot well be more than twenty or twenty- 
 five feet wide. These objections are obviated, and the 
 hay carried fifty or a hundred feet horizontally, by means 
 of Hick's Elevator and Carrier, of which the following 
 clear and full description is given in the Report of the 
 Auburn Trial of Implements : — " It consists of a track, 
 made of 2 by 5-inch plank, fastened to the rafters a few 
 inches below the ridge of the barn by 1^-inch square 
 strips and twelve-penny nails. Upon this track runs a 
 car ; a rope passes through it, and through a catch pulley 
 attached to a horse hay-fork, then back to the car ; the 
 other end passes back to the end of the barn, and returns 
 through pulley wheels to the barn floor, to which end a 
 horse is attached. 
 
 By a peculiar arrangement of the car, it is held in posi- 
 tion on the track, over the load to be unloaded, until a 
 forkful of hay is elevated to it, when it is liberated from 
 
HAY CARRIERS. 181 
 
 its position, and the fork made fast to the car in one oper- 
 ation, then it moves off on the track very easily, and any 
 distance you may choose to have it carried ; the operator, 
 by pulling a cord, trips the fork, and the horse, turning 
 around, walks or trots back to the place of starting ; the 
 car is pulled back to its position by the trip cord, when 
 the fork descends for another load. 
 
 The fork comes back so easily and quickly that the 
 horse can be kept in motion continually, elevating from 
 300 to 400 pounds of hay, and carrying it forty to fifty 
 feet in a horizontal direction, and returning for another 
 load in less than a minute. 
 
 Its advantages over the old mode are : 
 
 1st. — The hay can be carried into the second, third, and 
 fourth bays from the wagon, as easily as into the first, 
 thus saving a large amount of labor in the mows. 
 
 2d. — The hay is elevated perpendicularly from the load, 
 thus obviating the friction caused by dragging the forkful 
 of hay over and against the beam ; also the danger of 
 tripping or breaking the fork as it is drawn over the beam. 
 
 3d. — The car and fork return so easily, the fork drop- 
 ping in the middle of the load, ready to be thrust into the 
 hay immediately ; whereas, in the old method, it is very 
 hard work to get the fork back, if the hay has been car- 
 ried any distance. 
 
 4th. — The horse turns around, and walks or trots back 
 to the place of starting, instead of backing, thus saving 
 much labor to both horse and driver. 
 
 5th. — The hay need be elevated only high enough to 
 clear the highest beam, when it can be carried horizon- 
 tally, until the mows are more than half full, when, by 
 shortening a rope, the fork can be made to pass along 
 only sixteen inches below the very peak of the barn. 
 
 6th. — It requires but very little force to carry the hay 
 horizontally, whereas, by the old methods, it requires 
 more force to carry it horizontally than to elevate it. 
 
182 
 
 MECHANICS. 
 
 Fig. 206. 
 
 7th. — By extending the track four feet beyond t'he end 
 of the building, hay can be elevated and carried into 
 long, low hovels, or cow barns, when no other arrange- 
 ment would work at all. 
 
 The car is small, and the track light and simple ; a 
 weight has been lifted of 1,0S0 pounds by it at one time, 
 with a pair of mules." 
 
 By using a strong car, it may be employed for unload- 
 ing coal from a boat. 
 
 Building Stacks. — Three long poles may be used for 
 this purpose, securely chained at the top, and spread in 
 the form of a tripod. The one to which the lower pulley 
 is attached should be set firmly into the ground, to pre- 
 vent displacement by the outward draught. Holes are 
 bored into the poles at convenient distances, and cross 
 
 pieces secured to them, for holding 
 the board slide, and permitting it 
 to be gradually raised, as the stack 
 goes up. The hay may be pitched 
 from the ground as well as from a 
 load, without inconvenience, to any 
 height. 
 
 Instead of chaining the poles to- 
 gether, they may be firmly secured 
 by using two stout clevises, the 
 
 bolts of which are passed through 
 Mode of Cmpling the Poles. mgQt hol ^ near the upper endg 
 
 of the poles, (fig. 206). 
 
 Palmer's Hay Stacker, represented in fig. 207, has 
 been much used at the West, where large quantities of 
 hay are deposited out of doors. It first elevates the hay, 
 and then swings it around over the stack, dropping it 
 where desired. It docs not drag the hay against the 
 side of the stack, requires no staking down to prevent 
 tipping, and is easily drawn on the sills as runners, to any 
 part of the farm. The horizontal motion of the crane is 
 
palmer's hay stacker. 
 
 183 
 
 Fte. so- 
 
 effected as follows : — Two ropes are attached to the whiffle- 
 tree, one, a strong one, to elevate the hay, running on the 
 pulleys at B, C, and D ; and the other, a smaller one, pass- 
 ing the swivel pulley at A, on the 
 end of the lever _Z?, extending from 
 the foot of the upright shaft. This 
 cord then passes up and over a 
 pulley above the weight K The 
 weight is about four pounds, and is 
 attached to the end of the smaller 
 cord. At the same time that the 
 horse, in drawing, elevates the fork 
 with its load of hay, the weight 
 E is raised until it strikes the pul- 
 ley, when the power 
 of the horse becomes 
 applied to the end of 
 the lever JB, causing 
 it to revolve, and 
 
 swing the hay over '^^ = "^^^^ e * =tx ^ J *^ 
 
 the Stack. As the Palmer's Hay Stacker. 
 
 horse backs, the weight drops again to the ground, 
 taking up the slack rope from under the horse's feet, and 
 the weight of the fork causes the arm of the derrick to 
 revolve back over the load. The intended height for 
 raising the hay, before swinging, is regulated by length- 
 ening or shortening the smaller cord, as the arm will not 
 revolve until the weight strikes the pulley under the 
 head block. T. G. & M. W. Palmer, of Chicago, own 
 this invention, and furnish the smaller parts of the ma- 
 chine, the heavier being easily made on the farms where 
 intended to be used. 
 
 Fig. 208 shows the manner in which Raymond's Ele- 
 vator is mounted for stack building. These poles need 
 not be so heavy as when three poles alone are used. They 
 are kept from being drawn over towards each other in 
 
184 
 
 MECHANICS. 
 
 elevating heavy loads, by lashing the lower end of each 
 outer pole to a strong stake, driven into the ground 
 obliquely, by first making a hole with a crow-bar. It is 
 convenient to place the two pole tripods sufficiently dis- 
 tant from each other to give room for the stack, or rick, 
 
 Fiff. 208. 
 
 Fork on Poles for Building Stacks. 
 
 and to allow the wagon to pass within them. The eleva- 
 tor first lifts its load, and then carries it along the rope, 
 till the man on the load drops it by a jerk of the cord. 
 This apparatus is made by J. II. Chapman, of Clayville, 
 N. Y. 
 
 HAY PRESSES. 
 
 Among the best Hay Presses in the country is the one 
 manufactured by L. & P. K. Dederick, Albany, and rep- 
 resented in the annexed engraving. It is worked by one 
 or two horses, operating with great force by means of 
 the arms on each side, which are connected with toggle- 
 joint levers, explained in a former part of this work. The 
 hay is thrown in from the upper platform, and when re- 
 duced to compact bales, by means of the powerful force 
 which this press gives, is taken out at the lower. In order 
 to prevent the necessity of the horses running back at 
 
pedeuick's hay pkess. 
 
 Fijr. 209. 
 
 185 
 
 DedericVs Hay Press. 
 the pressure of every bale, Dederick's patent capstan (fig. 
 210) is employed with this press. 
 The horse or horses, in passing 
 around, wind up the rope on a 
 horizontal wheel or drum. The 
 possibility of any accident by 
 slipping backwards is prevented ^ 
 by the pawl or anchor, E, at the rjjpg|gjg 
 end of the lever, When the 
 
186 MECHANICS. 
 
 pressure is completed, the driver touches the upright rod, 
 and detaches the wheel or drum, by which the rope is 
 drawn backwards, without stopping the horses, which 
 continue to walk around the circle. 
 
 This capstan answers an admirable purpose in using 
 the common horse hay-fork, by obviating the necessity of 
 backing up at every forkful. 
 
 The New York Beater Press Company, of Little Falls, 
 manufacture a press, working like a pile engine, and re- 
 ducing the hay to a degree of compactness nearly equal 
 to that of solid wood. These bales are well adapted to 
 long conveyance by land or shipment to foreign ports. 
 
 Hay Loaders. — Several of these, of different construc- 
 tion, have been tried to a limited extent, but, so far, the 
 experiments have been but partially successful, or the 
 machines have not proved themselves fully adapted to 
 general use. Their expense, when compared with the horse- 
 fork, and, to some degree, their cumbersome character, 
 have proved objections. They mostly require very smooth 
 meadows, are often difficult to work in the wind, and 
 those constructed on the endless-rake principle are found 
 to carry up small stones or gravel into barley, endangering 
 the thrashing machine. Further ingenuity and labor on 
 the part of inventors appear to be required, to place them 
 generally within the reach of farmers. 
 
 CHAPTER XIII. 
 
 THRASHING, GRINDING, AND PREPARING PRODUCTS. 
 THRASHING MACHINES. 
 
 The old mode of beating out grain with the hand flail, 
 (fig. 211,) has now nearly passed away, and thrashing 
 machines have come into general use. 
 
VALUE OF THRASHING MACHINES. 187 
 
 S. E. Todd makes the following statement relative to 
 the saving of labor effected by these machines: "I have 
 thrashed a great deal of grain of all kinds, with my own 
 
 flail; and I have talked with 
 others who have been accustomed 
 to thrash their grain with flails, 
 and I have come to the conclusion 
 thr.t the following figures rep- 
 resent a fair average as to the 
 quantity of grain that an ordinary 
 laborer will be able to thrash and 
 clean in a day, viz. : Seven bushels 
 An Old Flail. of wheat, eighteen bushels of oats, 
 
 fifteen bushels of barley, eight bushels of rye, and twenty 
 bushels of buckwheat. In order to make this more intelligi- 
 ble, it will be necessary to double the number of bushels 
 that one man is able to thrash, as two men will be requir- 
 ed to clean the grain with a fanning mill. 
 
 "In order to labor economically and advantageously 
 with a thrashing machine, two horses, at least, and three 
 men are necessary. In most instances four or five men 
 will be required, which will make a force equal to fifteen 
 men with flails. Such a gang of hands, and two good 
 horses, with such a thrasher and cleaner as Harder's, are 
 capable of thrashing and cleaning of the same kind of 
 grain to which allusion has been made, one hundred and 
 seventy bushels of wheat, three hundred and twenty-five 
 of oats, two hundred and twenty of barley, one hundred 
 and eighty of rye, and two hundred and sixty of buck- 
 wheat. Some manufacturers of thrashing machines fix 
 the average day's work higher than these figures. In 
 some instances, I will acknowledge that a span of horses 
 and five men can do much more than the amount repre- 
 sented by the foregoing figures ; yet I am satisfied that in 
 the majority of instances they will not thrash and clean a 
 greater number of bushels than I have indicated. But. 
 
188 
 
 MECHANICS. 
 
 even at the low figures that I have recorded, such a ma- 
 chine as Harder's, or Palmer's Climax, or Wheeler, Melick 
 & Co.'s, will be found to be a great labor-saving machine 
 for thrashing all kinds of grain. 
 
 "There is one consideration that should not be over- 
 looked in this estimate, which is the much greater amount 
 of labor performed, with far less fatigue. When one la- 
 borer can perform the work of two or more workmen with 
 less fatigue than has usually been required, a great point 
 is gained." 
 
 J. Stanton Gould, estimating from a large number of 
 statements that a saving of five per cent of the grain is 
 effected by using the machine, over thrashing by the flail, 
 computes the aggregate annual saving in the United States 
 to be over eight million bushels of wheat, two million 
 of rye ; eight million of oats, and nearly a million of barley. 
 
 For farms of moderate size, the endless-chain powers 
 for driving thrashing machines are most convenient, being 
 
 Fig. 212. 
 
 E?idlcss-chain horse-power, driving a thrashing-machine, 
 
 compact or requiring but little room, easily conveyed from 
 one place to another, and readily applicable to sawing 
 wood, cutting straw, and to various other purposes. Fig. 
 212 represents a single horse-power, driving a small thrash- 
 ing machine, with a simple, horizontal separator and straw 
 
TO MEASURE ENDLESS CHAIN POWER. 
 
 189 
 
 carrier; and fig. 213 shows a two-horse power, (Emery's,) 
 with the wheel-work on which the endless platform runs. 
 The power of these machines, and the amount of fric- 
 tion in running them, may be easily ascertained by the 
 rule, already given in a former part of this work, for de- 
 termining the power of the inclined plane ; for the only 
 
 Fig. 213. 
 
 Two-horse Tread Power. 
 
 difference between the endless chain and a common in- 
 clined plane is, that in one the plane is fixed, and the body 
 moves up its surface, and in the other the plane itself 
 moves downward, and the weight or animal upon it re- 
 mains stationary. The same principle applies in both cases. 
 
 First, to ascertain the friction, let the platform be placed 
 on a level, with the horse upon it; then gradually raise 
 the end until the weight of the horse will just give it mo- 
 tion. This will show the precise amount of the friction ; 
 for if the end be elevated one-twentieth of its length, 
 then the friction is one-twentieth the weight of the horse 
 and platform. 
 
 Secondly, to determine the power, when the end is still 
 further raised, measure the difference between the height 
 thus given and the length of the platform. If, for in- 
 stance, the height of the inclination is one-eighth of its 
 length, and the horse is found to weigh eight hundred 
 pounds, then the power is one hundred pounds, or one- 
 eighth the weight of the horse. 
 
190 
 
 MECHANICS. 
 
 Fig. 214. 
 
 This rule will not, however, apply, when the draught 
 of the horse is added to its weight ; for it usually happens 
 that the weight alone is not sufficient, without placing the 
 platform in too steep a position for the horse to work 
 comfortably. He is, therefore, attached to a whiffle-tree, 
 and to ascertain the power requires the use of the dyna- ^ 
 mometer, in connection with the preceding mode. 
 
 Great improvement has been made of late years in 
 
 the appendages of 
 thrashing machines. 
 The large number 
 of laborers formerly 
 employed in raking 
 and separating the 
 straw, and placing it 
 on the stack, is now 
 dispensed with, and 
 the whole done by 
 machinerv, working: 
 by the same power 
 that drives the 
 thrasher. Among the best and most widely known ma- 
 chinery for this purpose is that invented by H. A. Pitts, 
 and represented in a portable form by fig. 214. It sepa- 
 rates the grain, cleans it, and carries the straw by means 
 of the elevator, (shown folded in the cut,) to the top of 
 the highest stack. 
 
 The tread-power is successfully applied to churning, as 
 shown in the cut, (fig. 215.) The employment of a sheep, 
 of one of the larger breeds, has been found better and 
 more convenient than a dog, as it is heavier, more quiet, 
 less averse to the labor, and when the task is done, it is 
 turned into the yard or pasture, where it is readily found 
 next time. 
 
 The cost of horse-powers and thrashers combined, of 
 the different forms, varies from $225 to $400. 
 
 fsrc^e^-*-*~<~- 
 
 Pitts' Thrasher and Straw Carrier. 
 
CORN SHELLERS. 
 
 191 
 
 Fig. 215. 
 
 Chum worked by dog-potucr. 
 
 Corn Shellers arc made for both hand and horse- 
 power. One of the most convenient and compact hand 
 machines is BurralVs, made of iron, furnished with a fly- 
 wheel to equalize 
 velocity, and worked 
 by one person while 
 another feeds it, one 
 ear at a time. Or, one 
 person alone will turn 
 it with one hand, while 
 the ears are dropped 
 in with the other. 
 Several other good 
 corn shellers are made 
 mostly of wood. 
 
 Fig. 217 represents 
 a sheller, mostly of 
 cast iron, driven by 
 horses, by means of BurraCTs Corn Shdler. 
 
 the band partly seen in the cut. The corn in the ear is 
 thrown into the hopper at one end, and is separated from 
 
192 
 
 MECHANICS. 
 
 the cob by rows of teeth revolving in a concave bed and 
 
 Fig. 817. 
 
 Horse-power Corn Shelter. 
 set spirally, thus carrying the cobs along and ejecting 
 them from the opposite end. 
 
 For shelling corn in large quantities, powerful machines 
 driven by horses or steam are required. An excellent 
 sheller for this purpose is made by Richards, of Chicago. 
 The corn is shoveled directly from the wagon or crib in- 
 to the hopper, and requires no extra feeders, or hands, 
 to keep the machine from choking. It is built wholly 
 
 of iron, combining 
 strength and dura- 
 bility. The shellers 
 are made of difFerent 
 sizes requiring from 
 two to twelve horse- 
 power. The former 
 will shell one bushel, 
 ffichards' Com Shelter. an d the latter ten 
 
 bushels per minute. The cost varies from $175 to $475. 
 The following is a description of the working part. 
 
 The shelling cylinder is made of heavy rods of wrought 
 iron, placed equidistant, presenting a corrugated surface, 
 which cannot wear smooth. "Within this, a revolving iron 
 
Richard's corn sheller. 193 
 
 cylinder, with chilled teeth, thrashes the corn against the 
 surfaces of the rod cylinder. The teeth approach the 
 rods sufficiently close to keep every ear in rapid motion, 
 shelling one ear or one bushel with the same facility. A 
 regulator at the discharge end places the machine within 
 control of the operator. The spaces between the rods 
 allow the shelled corn to escape freely, thus lessening the 
 draught, relieving the cylinder from clogging and from all 
 liability to cut or grind the grain. 
 
 The cleaner consists of a cylindrical screen revolving 
 around the whole length of the sheller, and extending be- 
 yond it. A heavy fan blast passes directly through this 
 screen, and under it, subjecting the corn to two separate 
 cleanings, and delivering it in good condition for market. 
 The cleaned corn discharges upon either side desired, and 
 the cobs are delivered with the dust at the end of the ma- 
 chine. 
 
 ARCHIMEDEAN ROOT-WASHER. 
 
 The spiral principle has been successfully applied in the 
 Archimedean Root-washer, (fig. 219.) The roots to be 
 
 Fia 219. 
 
 CroskiWs Archimedean Root-washer. 
 
 Washed are first delivered into a hopper, from which they 
 
 9 
 
194 
 
 MECHANICS. 
 
 pass into an inclined cylinder made of strips of wood with 
 grate-like openings. The cylinder has two portions sepa- 
 rated by a partition, in the first of which they remain 
 while the handle is turned for washing them. As soon as 
 the washing is finished, the motion of the handle is re- 
 versed, which throws them into the other part, which has 
 a spiral partition, along which they pass until they drop 
 into a spout outside. 
 
 BOOT SLICERS. 
 
 These are mostly worked by hand. Out of a large 
 number of inventions for this purpose, two are here rep- 
 resented; — Wellington's, made of iron, the knives being 
 
 Pig. 221. 
 
 Ficr. 220 
 
 Wellington's Boot Cutter. Boot Cutter of Wood. 
 
 on a revolving cone within the hopper, and shown below 
 the machine ; the other of wood, with the knives on the 
 face of an iron wheel, which forms one side of the hopper. 
 These two machines will cut roots at the rate of about a 
 bushel per minute. 
 
VARIOUS KIXDS OF FARM! MILLS. 
 
 195 
 
 Fig. 222. 
 
 FARM MILLS. 
 
 • 
 
 These are made of iron, and with burr-stones. The 
 former are cheaper, and answer a good purpose for grind- 
 ing feed for domestic animals. The latter may be also 
 used for grinding flour. 
 
 Figure 222 represents an iron farm mill manufactured 
 by R. H. Allen & Co., of New York. The grinding sur- 
 faces are of chilled iron, 
 so arranged as to be 
 self-sharpening, and to 
 last a long time without 
 repairs. When necessary, 
 new plates are readily 
 inserted. The mill is 
 driven by horse or other 
 power, the band from 
 which is seen in the cut. 
 It will grind from five to 
 ten bushels per hour, 
 varying with the fineness 
 of the meal and the 
 amount of driving pow- 
 
 Fig. 223. 
 
 Allen's Horse Mill. 
 
 er. A two-horse railway power may be used to advantage. 
 
 This mill is about three feet 
 square, four feet high, and 
 weighs three hundred pounds. 
 Several other iron mills of a 
 similar character are made by 
 difFerent manufacturers, and 
 usually cost about $50. 
 
 Amonsj the burr-stone farm 
 ,mills, one of the best, most 
 compact, and most substan- 
 tial, is Forsmaii's^ of Chicago, 
 It will be perceived from this 
 
 Forsmmi's Mill. 
 
 represented by fig. 223. 
 
19G 
 
 MECHANICS. 
 
 figure that the spindle is horizontal, and the face of the 
 stones vertical. The frame is of iron. The diameters of 
 the stones vary from sixteen to thirty inches, and the 
 weight from 400 to 1,500 lbs. The smaller size may be 
 run with a power of one to four horses ; the larger, with 
 that of ten to thirty horses. Prices 8150 to $375. The 
 manufacturers claim that it will grind from one and a 
 half to three bushels j:>er hour, for each horse-power used 
 in driving it. 
 
 THE COTTON GIN. 
 
 Since the invention of the Cotton Gin by Eli Whitney, 
 great improvements have been made, by which the cotton 
 is cleaned with great rapidity and in a perfect manner. 
 
 Fig. 224. 
 
 Emery's Cotton Gin— Section. 
 
 The machine manufactured by H. L. Emery, of Albany," 
 is one of the best for this purpose. It is represented in 
 section in fig. 224. The hopper, at the right, is furnished 
 with what is termed a Picker Moll Svpporter, which re- 
 volves within the hopper, in the direction shown by the 
 arrow, and prevents the cotton from becoming packed. It 
 
emeey's cotton gust. 
 
 197 
 
 is then taken by the teeth of the saw cylinder, which re- 
 duce the cotton to a fine condition. These teeth are 
 swept by the brush cylinder, which, running in the same 
 direction with the teeth, and slightly faster, carries the 
 cotton off from them. Fig. 225 represents the operation, 
 the seed escaping from the bottom of the hopper and the 
 
 Fiff. 225. 
 
 Emery's Cotton Gin, with Condenser. 
 
 cotton thrown to the rear into the condenser, which fin- 
 ishes the cleaning process and packs or condenses the lint 
 cotton within a limited space. The arrows shown in the 
 section indicate the direction of the revolutions of the 
 picker, saws, and brush cylinder, and also the course 
 which the cotton takes in passing through the gin and 
 condenser. 
 
PART II. 
 
 MACHINERY IN CONNECTION WITH WATER. 
 
 GENERAL PRINCIPLES. 
 
 Htdeostatics * treats of the weight and pressure of 
 liquids when not in motion ; Hydraulics^ of liquids in 
 motion, as, conducting water through pipes, raising it by- 
 pumps, etc.; and Hydrodynamics J includes both, by- 
 treating of the forces of the liquids, whether at rest or in 
 motion. 
 
 CHAPTER I. 
 
 HYDROSTATICS. 
 UPWARD PRESSURE. 
 
 A remarkable property of liquids is their pressure in 
 all directions. If we place a solid body, as a stone, in a 
 vessel, its weight will only press upon the bottom ; but if 
 we pour in water, the water will not only press upon the 
 bottom, but against the sides. For, bore a hole in the 
 side, and the side pressure will drive out the water in a 
 stream ; or bore small holes in the sides and bottom of 
 a tight wooden box, stopping them with plugs ; then press 
 this box, empty, bottom downward, into water, allowing 
 none to run in at the top. Now draw one of the side 
 plugs, and the water will be immediately driven into the 
 
 * From two Greek words, hudor, water, and statos, standing, or at rest, 
 t From two Greek words, hudor, water, and aulos, a pipe. 
 t From two Greek words, hudor, water, dunamis, power. 
 198 
 
UPWARD PRESSURE OF LIQUIDS. 199 
 
 box by the pressure outside. If a bottom plug be drawn, 
 the water will immediately spout up into the box, show- 
 ing the pressure upward against the bottom. Hence the 
 pressure in all directions^ upward, sideways, and down- 
 ward, is proved. 
 
 The upward pressure of liquids may be shown by pour- 
 ing into one end of a tube, bent in the shape of the letter 
 U, enough water to partly fill it ; the upward pressure will 
 drive the water up the other side until the two sides are 
 level. 
 
 On this principle depends the art of conveying water 
 in pipes under ground, across valleys. The water will 
 rise as high on the opposite side the valley as the spring 
 which supplies it. The ancient Romans, who were unac- 
 quainted with the manufacture of strong cast-iron pipes, 
 conveyed water on lofty aqueducts of costly masonry, 
 built level across the valleys. Even at the present day, 
 it has been deemed safest to build level aqueducts for con- 
 veying great bodies of water, as in very large pipes the 
 pressure would be enormous, and might result in violent 
 explosions. 
 
 If the valleys are deep, the pipes must be correspond- 
 ingly strong, because, the higher the head of water, the 
 greater is the pressure. For the same reason, dams and 
 large cisterns should be strongest at bottom. Reservoirs 
 made in the form of large tubs require the lower hoops to 
 be many times stronger or more numerous than the upper. 
 
 MEASUREMENT OP PRESSURE AT DIFFERENT HEIGHTS. 
 
 The amount of pressure which any given height of wa- 
 ter exerts upon a surface below may be understood by 
 the following simple calculation : 
 
 If there be a tube one inch square (with a closed end), 
 half a pound of water poured into it will fill it to a height 
 
200 
 
 MACHINERY IN CONNECTION WITH WATER. 
 
 of fourteen inches ;* one pound will fill it twenty-eight 
 
 Fi£. 226. 
 
 2 lbs. 5Q5n. 
 
 
 iy2.lbs.Alin, 
 
 lib 28 in. 
 
 inches; two pounds, fifty-six inches; 
 ten pounds, twenty-three feet ; twenty 
 pounds, forty-six feet, and so on. 
 Now, as the side pressure is the same 
 as the pressure downward for the 
 same head of water, the same column 
 will, of course, exert an equal pressure 
 on a square inch of the side of the 
 tube. Or, if the tube be bent, as 
 shown in the annexed figure (fig. 
 226), the pressure upward on the end 
 of the tube, at a, will be the same for 
 the various heights. 
 
 Now, as the pressure of a column 
 fifty feet high is about twenty-two 
 pounds on a square inch, the pressure 
 on the four sides is equal to eighty- 
 eight pounds for one inch in length. 
 Hence the reason that considerable 
 strength is required in tubes which 
 
 have much head of water, to prevent their being torn 
 
 open by its force. 
 
 yfelb-ldin. 
 
 DETERMINING THE STRENGTH OE PIPES. 
 
 The question may now arise, and it is a very important 
 one, How thick must be a lead tube of this size to prevent 
 danger of bursting with a head of fifty feet, or of any 
 other height ? To answer it, let us turn to the table of 
 the Strength of Materials in a former part of this work, 
 where we find that a bar of cast lead one-fourth of an 
 inch square will bear a weight of fifty-five pounds. If the 
 
 * This is nearly correct, for a cubic foot (or 1,728 cubic inches) of 
 water weighs 62 lbs. Consequently, one pound will be 27.9 cubic inch- 
 es, and will fill the tube nearly 28 inches high. 
 
CALCULATING TIIE STRENGTH OF TUBES. 201 
 
 tube be only one-sixteenth of an inch thick, one inch of 
 one of its sides will possess an equal strength, that is, 
 will bear fifty-five pounds only, and the tube would conse- 
 quently burst with fifty feet head. If one-tenth of an 
 inch thick, the tube would just bear the pressure, and, to 
 be safe, should be about twice as thick, or one-fifth of an 
 inch. Half this thickness would be sufficient for twenty- 
 five feet of water, and would require to be doubled for 
 one hundred feet. A round tube, one inch in diameter, 
 having less surface to its sides, would be about one-third 
 stronger. A tube twice the diameter would need twice 
 the thickness ; or if less in diameter, a proportionate de- 
 crease in thickness might take place. If, instead of cast 
 lead, milled lead were used, the tube would be nearly four 
 times as strong, according to the table of the strength of 
 materials already referred to. 
 
 SPRINGS AND ARTESIAN WELLS 
 
 result from the upward pressure of water. Rocks are 
 usually arranged in inclined layers (fig. 227), and when 
 
 Fig. 22?. 
 
 rain falls upon the surface, as at c d, it sinks down in the 
 more porous parts between these layers, to c. If the lay- 
 ers happen to be broken in any place below, the water 
 finds its way up through the crevices by the pressure of 
 the head above, and forms springs. If there are no open- 
 ings through the rocks, deep borings are sometimes made 
 9* 
 
202 
 
 MACHINERY IX CONNECTION WITH WATER. 
 
 artificially, through which the water is driven up to the 
 surface, as at <?, forming what are termed Artesian Wells. 
 The head of water which supplies them may be many 
 miles distant, the place of discharge being on a lower 
 level. It has sometimes been found necessary to bore 
 more than a thousand feet downward before obtaining 
 water which will flow out freely at the surface of the earth. 
 
 ifi 
 
 
 1=4=1 
 
 
 1=1=== 
 
 
 
 = —< 
 
 DETERMINING THE PRESSURE ON GIVEN SURFACES. 
 
 The pressure of liquids upon any given surface is always 
 exactly in proportion to the height, no matter what the 
 Fig. 228. shape of the vessel may be. If, 
 
 for instance, the vessel a (fig. 
 228), be one inch in diameter, 
 and the vessel b be three inches 
 in diameter, the water being 
 equally high in both, the press- 
 ure on the whole bottom of b 
 will be nine times as great as on 
 the bottom of a ; or any one inch of the bottom of b will 
 receive as great a pressure as the bottom of a. Again, if 
 the vessel c, broad at the top, be narrowed to only an 
 inch in diameter at bottom, the press- Fig. 229. 
 
 tire upon that inch will still be the 
 same, most of the weight of its con- 
 tents resting against the sides, d d. 
 If the vessel, A (fig. 229), be filled 
 with water to a height of fourteen 
 inches, the pressure will be half a 
 pound on every square inch of the 
 bottom, or upon every square inch 
 of the sides fourteen inches below the surface. If the 
 tube, C, be an inch square, the water will be driven into 
 it with a force of half a pound, and will press with that 
 force against the one-inch surface of the stop-cock, C. If 
 
A PUZZLE EXPLAINED. 
 
 203 
 
 the tube, B, be now filled to an equal height, the same 
 force will be exerted against the other side. To prove 
 this, let the stop-cock be opened, when the two columns 
 of water will remain at an exact level. 
 
 If enough water be now poured into the tube, B, to fill 
 if to the top, it will immediately settle down on a level 
 with the water in A, raising the whole surface in the lat- 
 ter. This result has seemed strange to many, who can 
 not conceive how a small column of water can be made to 
 balance a large one, and it has been therefore termed the 
 Hydrostatic Paradox. But the difficulty entirely vanish- 
 es, and ceases to appear a paradox, when we remember 
 that the water in the larger vessel rises as much more 
 slowly than it descends in the smaller, as the large one 
 exceeds the smaller ; thus acting on the principle of vir- 
 tual velocities in precisely the same manner that a heavy 
 weight on the short end of a lever is upheld by a small 
 weight on the long end. The great mass of water is sup- 
 ported directly by the bottom of A, in the same way that 
 nearly all the weight on the lever is supported by the 
 Fig. 230. fulcrum. A man who was seeking a solu- 
 
 tion to the absurd mechanical problem of 
 perpetual motion, and who supposed that 
 the large mass in A would overbalance the 
 small column in B, and drive it upward, 
 constructed a vessel in the form shown in 
 fig. 230, so that the small column, when 
 forced upward, would flow back into the 
 larger vessel perpetually.. He was, how- 
 'Motion.' ever, greatly surprised to see the fluid in 
 both divisions settle at the same level. 
 
 This principle may bo further explained by the following 
 experiment : A B (fig.231) represents the inside of a metallic 
 vessel, with a bottom, C, which slides up and down, water- 
 tight. If water be poured in to fill the lower or larger 
 part only, it will be found to j^ress on the sliding bottom 
 
 Attempted Perpetual 
 
204 
 
 MACHINERY IN CONNECTION WITH WATER. 
 
 with a force exactly equal to its own weight ; that is, if 
 there is a pound of water, it will press on the bottom with 
 a force equal to one pound. Now, if the bottom be pushed 
 rig. 231. upward, so as to drive the water into the 
 
 narrow part of the vessel, the pressure upon 
 the bottom becomes instantly much greater, 
 or equal to many pounds, the water being 
 the same in quantity, but with a much 
 higher head than before. Suppose the nar- 
 row part of the vessel is twenty times 
 smaller than the larger part, then, in pushing 
 the bottom up one inch, the water is driven 
 twenty inches upward in the tube. So then, 
 according to the rule of virtual velocities, it will require 
 twenty times the force, because it moves upward twenty 
 times faster.* This, then, is precisely similar to the in- 
 stance where a pound on the longer end of a steelyard 
 balances twenty pounds on the shorter ris# 232# 
 
 end. In this instance, the upper parts, <gH^0 
 
 T) D, of the vessel operate as the fulcrum 
 of a lever, and offer resistance to the slid- 
 ing part as soon as the water begins to 
 ascend the tube. ^ 
 
 HYDROSTATIC BELLOWS. 
 
 This principle is shown in the Hy- 
 drostatic Bellows (fig. 232), which con- 
 sists Of tWO round pieces Of board, Hydrostatic Bellows. 
 
 connected by a narrow strip of strong leather ; into it is 
 inserted a long, narrow tube, B, with a small funnel, e, at 
 the top. When water is poured into this tube, it will 
 raise a weight as much greater than the weight of the 
 
 * The pressure will be as great upon tue bottom as if tlie vessel con- 
 tinued a uniform size all tue way up. 
 
HYDEOSTATIC PKESS. 205 
 
 water in the tube as the surface of the upper board ex- 
 ceeds the cross-section of the tube. Thus, if a pound of 
 water fills a tube half an inch in diameter, and the bellows 
 are two feet in diameter, then this pound will raise more 
 than two thousand pounds on the bellows (if it be strong 
 enough), because the surface of the bellows is more than 
 two thousand times greater. 
 
 In the same way, a strong, iron-bound hogshead may 
 be burst with the weight of a single gallon of water by 
 pouring it into a long and narrow tube set upright in 
 the bung of the filled hogshead. If, for instance, the inner 
 surface of the hogshead be 20 square feet, or 2,880 square 
 inches, a tube of water 23 feet high will press with a force 
 of 10 pounds on every square inch, or equal to a force of 
 28,800 pounds, or 14 tons, on the whole surface. 
 
 HYDEOSTATIC PEESS. 
 
 The Hydrostatic Press owes its extraordinary power to 
 a similar principle ; but, instead of a bellows, there is a 
 moving piston in a strong metallic cylinder ; and instead 
 of being worked by the mere weight of the water, it is 
 driven into the cylinder by means of the lever of a pow- 
 erful forcing-pump. An instrument of this sort, possess- 
 ing enormous power, was used to elevate the great tubular 
 iron bridge in England. It was found necessary to make 
 the sides of the cylinder into which the water was driven 
 no less than eleven inches thick, of solid iron ; and so 
 great was the pressure given to the confined water, as 
 to have forced it up through a tube higher than the 
 summit of Mont Blanc. I'n the port of New York, ves- 
 sels of a thousand tons' burden have been lifted by the 
 hydrostatic press. 
 
 This machine has been applied in compressing hay, cot- 
 ton, and other bulky substances into a compact form, so 
 that they may occupy but little space, for conveyance to 
 
206 
 
 MACHINERY IN CONNECTION WITH WATER. 
 
 distant markets. The following figure (fig. 233) exhibits 
 the different parts of this powerful machine. A is a cis- 
 tern to supply water, which is raised by working the han- 
 dle, B, of the forcing-pump ; the water passes through the 
 valve, C, opening upward, and through the spring valve, 
 
 Fig. 233. 
 
 Hydrostatic Press. 
 
 D, opening toward the large cylinder, E. Being thus 
 driven into the space, E, it raises the piston, F, and exerts 
 a prodigious pressure upon the mass of hay or cotton, G. 
 The piston is lowered by turning the screw, H, which al- 
 lows the water to pass back into the cistern at I. In the 
 figure the hay or cotton is shown as visible to the sight, 
 in order to represent the whole more plainly ; but in prac- 
 tice it is thrown into a square box or chamber of strong 
 plank, of the size of the intended bundle. One side is 
 
HYDROSTATIC PEESS. 20? 
 
 hung upon stout hinges, and is opened for the removal of 
 the bale when the pressing is completed. 
 
 To estimate the power of this machine, divide the 
 square of the diameter of the piston, F, by the square of 
 the diameter of the piston of the forcing-pump, and multi- 
 ply the quotient by the power of the lever, B. For ex- 
 ample, suppose the piston, F, is 16 inches in diameter, and 
 the piston of the forcing-pump is 2 inches in diameter. 
 The square of 16 is 256 ; divide this by 4, the square 
 of 2, and the result will be 64. If the lever, B, increases 
 the power five times, the whole power of the machine will 
 be 320; that is, a force of one pound applied to the lever 
 will raise the large piston with a force equal to 320 pounds ; 
 or, if a force of 100 pounds be given to the lever, the 
 power will be 32,000 pounds, or 16 tons. Reducing the 
 diameter of the smaller piston to half an inch, and in- 
 creasing the force of the lever to twenty times, the whole 
 power exerted will be thirty-two times as great, or equal 
 to 960 tons. In ordinary practice, it is more convenient 
 and economical to reduce the diameter of the larger piston 
 to a few inches only, making the forcing-pump correspond- 
 ingly small, the power depending entirely on the dispro- 
 portion between them. Such presses may be worked rap- 
 idly by horse, water, or steam power. 
 
 One great advantage which the hydrostatic press pos- 
 sesses over those worked by screws results from the little 
 friction among liquids, nearly the only friction existing in 
 the whole machine being that of the two pistons, which is 
 comparatively small. Another is the smallness of the 
 compass within which the whole is comprised ; for a man 
 might, with one not larger than a tea-pot, standing before 
 him on a table, cut through a thick bar of iron with as 
 much ease as he could chip pasteboard with a pair of 
 shears. 
 
208 
 
 MACHINERY IN CONNECTION WITH WATER. 
 
 SPECIFIC GRAVITIES. 
 
 Fig. 2*4. 
 
 In connection with Hydrostatics, the subject of the 
 specific gravities of bodies is one of importance. The 
 specific gravity of a substance is its comparative weight 
 with some other substance, an equal bulk of each being 
 taken. Water is usually the standard for comparison. 
 
 To ascertain the specific gravity, weigh the body both 
 in and out of water, and observe 
 the difference; then divide the 
 whole weight by this difference, and 
 the quotient will be the specific 
 gravity sought. For example, if a 
 stone weighs 12 lbs. out of water 
 and 7 lbs. in water, divide 12 by 
 5, and the quotient is 2.4, which 
 shows that the stone is 2 4 | J0 times 
 heavier than water. Figure 234 
 shows the mode of weighing the 
 body in water, by suspending it be- 
 neath a balance on a hair or thread. 
 
 It was in a similar way that Archimedes is said to have 
 succeeded in detecting the suspected fraud in the manu- 
 facture of the golden crown of the ancient king of Syra- 
 cuse. He first weighed it, and then found that it dis- 
 placed more water when plunged in a vessel just filled, 
 than a piece of pure gold, and also that it displaced less 
 than silver, whence he inferred the mixture of these two 
 metals. 
 
 When the specific gravity of a substance lighter than 
 water is to be ascertained, it is loaded down by a weight, 
 so as to sink in water, for which allowance is made in the 
 calculation. A very simple way to determine this in dif- 
 ferent kinds of wood is to form them into rods or sticks 
 of uniform size throughout, and then to observe what 
 portion of them sink when placed endwise in water. 
 
 Instrument for taking Specific 
 Gravities. 
 
TABLE OF SPECIFIC GRAVITIES. 
 
 209 
 
 A knowledge of the specific gravities of various sub- 
 stances becomes useful in many ways, among which is 
 ascertaining the weight of any structure, machine, or im- 
 plement, by knowing that of the material used in its man- 
 ufacture ; determining the cost, by the pound, of such 
 material ; or knowing the bulk or size of any load for a 
 team. The latter may often be of great use in ordinary 
 practice, by enabling the teamster to calculate beforehand 
 the amount of load to give his horses, whether in timber, 
 plank, brick, lime, sand, or iron, without first subjecting 
 them to overstraining exertions in consequence of error in 
 random guessing. 
 
 Tables of specific gravities, for this purpose, and weights 
 of a cubic foot of different substances, are here given. 
 
 TABLE OP SPECIFIC GRAVITIES. 
 
 Metals. 
 
 Gold, pure. 19.36 
 
 " standard 17.16 
 
 Mercury 13.58 
 
 Lead 11.35 
 
 Silver 10.50 
 
 Copper 8.83 Zinc 
 
 Iron 7.78 
 
 " cast 7.20 
 
 Steel 7.82 
 
 Brass, common 7.82 
 
 Tin 7.29 
 
 6.86 
 
 Stones and Earths. 
 
 Brick 1.90 
 
 Chalk 2.25 to 2.66 
 
 Clay 1.93 
 
 Coal, anthracite, about 1.53 
 
 Coal, bituminous 1.27 
 
 Charcoal 44 
 
 Earth, loose, about .' 1.50 
 
 Flint 2.58 
 
 Granite, about 2.65 
 
 Gypsum 1.87 to 2.17 
 
 Limestone 2.38 to 3.17 
 
 Lime, quick 80 
 
 Marble 2.56 to 2.69 
 
 Peat 60 to 1.32 
 
 Salt, common 2.13 
 
 Sand 1.80 
 
 Slate 2.67 
 
 Woods — dry. 
 
 Green wood often loses one-third of its weight by seasoning, and 
 sometimes more. The same kind varies in compactness with soil, 
 growth, exposure, and age of the trees. 
 
210 
 
 MACHINERY IN CONNECTION WITH WATER. 
 
 Apple 68 to .79 
 
 Ash, -white 73 to .84 
 
 Beech - 73 to .85 
 
 Box 91 to 1.32 
 
 Cherry 71 
 
 Cork .21 
 
 Elm 58 to .67 
 
 Hickory 84 to 1.00 
 
 Maple 65 to .75 
 
 Pine, white 47 to .56 
 
 Pine, yellow 55 to .66 
 
 Oak, English 93 to 1.17 
 
 " white 85 
 
 " live 94tol.l2 
 
 Poplar, Lombardy 40 
 
 Pear 66 
 
 Plum 78 
 
 Sassafras 48 
 
 Walnut 67 
 
 i Willow 58 
 
 Miscellaneoits. 
 
 Beeswax 96 
 
 Butter 94 
 
 Hone)' 1.45 
 
 Lard 94 
 
 Milk 1.03 
 
 Oil, linseed 94 
 
 Oil, whale 92 
 
 " turpentine 87 
 
 Sea water 1.02 
 
 Sugar 1.60 
 
 Tallow 93 
 
 Vinegar 1.01 to 1.08 
 
 Weights of a Cubic Foot of various Substances, from which the Bulk of a 
 Load of one Ton may be easily calculated. 
 
 Cast Iron 450 pounds. 
 
 Water 62 
 
 White pine, seasoned, about 30 
 
 White oak, " " 52 
 
 Loose earth, about 95 
 
 Common soil, compact, about 124 
 
 Clay, about 135 
 
 Clay with stones, about 160 
 
 Brick, about 125 
 
 Bulk of a Ton of different Substances. 
 
 23 cubic feet of sand, 18 cubic feet of earth, or 17 cubic feet of clay, 
 make a ton. 18 cubic feet of gravel or earth before digging make 27 
 cubic feet when dug ; or the bulk is increased as three to two. There- 
 fore, in filling a drain two feet deep above the tile or stones, the earth 
 should be heaped up a foot above the surface, to settle even with it, 
 when the earth is shoveled loosely in. A cubic foot of solid half-rotted 
 manure weighs about 56 lbs., requiring about 36 cubic feet to the ton. If 
 coarse or dry, more will be required. Hay varies much in specific grav- 
 ity with the kind, and the degree of pressure in the bay or stack ; but 
 good timothy hay, under medium pressure, requires about 500 cubic 
 feet to the ton ; clover, variable, — about one-half more. 
 
VELOCITT OF WATEK. 211 
 
 CHAPTER n. 
 
 HYDRAULICS. 
 VELOCITY. OP FALLING WATEK. 
 
 Liquids in motion are subject to the same laws as solids 
 in motion. Falling water increases in velocity at the 
 same rate that the motion of falling solids is accelerated, 
 as already explained under the head of Gravitation. Thus 
 a perpendicular stream of water descends one foot in a 
 quarter of a second, four feet in half a second, nine 
 feet in three-fourths of a second, and sixteen feet in one 
 second. Like falling solids, the velocity at the end of 
 the first quarter will be eight feet per second ; at the end 
 of the second quarter, sixteen feet; at the end of the third 
 quarter, twenty-four feet ; and at the end of the fourth 
 quarter, thirty-two feet per second. 
 
 Now, if there be an orifice made in the side of a vessel 
 of water, the water will spout out with the same swiftness 
 as if it fell perpendicularly from an equal height, were it 
 not retarded a little by friction. For example, if the 
 head of water is one foot above the orifice, the velocity 
 would be at the rate of eight feet per second, but for fric- 
 tion, which reduces it to about five and a half feet. The 
 velocity for any other height of head may be easily found 
 by deducting the same proportionate rate from the veloc- 
 ity of a falling body. Thus, for example, if the head be 
 sixteen feet, the speed would be thirty-two feet (as shown 
 under Gravitation), from which, deducting the friction, 
 the real velocity would be about twenty-two feet per 
 second. 
 
 It has been already shown that the velocity of a falling 
 body increases at the same rate as the increase in the time 
 of falling ; for instance, the speed is twice as great in two 
 seconds as in one ; three times as great in three seconds ; 
 
212 
 
 MACHINERY IN CONNECTION WITH WATER. 
 
 four times as great in four seconds, and so on. But the 
 distance fallen through increases as the square of the time ; 
 that is, it is four times as great in two seconds, nine times 
 as great in three seconds, sixteen times as great in four 
 seconds, etc. Thus we see that, jn order to produce a 
 twofold velocity, a fourfold height is necessary, etc. So 
 also in the escape of water under a head : to double the 
 velocity of the stream, the head must be four times as 
 high ; to triple it, the head must be nine times as high, etc. 
 
 DISCHARGE OF WATER THROUGH ORIFICES AND PIPES. 
 
 Fig. 235. 
 
 Fig. 236. 
 
 Fig. 237. 
 
 The discharge of water from a vessel is greatly influ- 
 enced by the nature of the orifice through which it flows. 
 
 If, for example, a 
 vessel or cistern 
 have a thin bottom 
 of tin, with a 
 smooth, circular 
 hole, we might natu- 
 rally suppose that 
 the discharge would 
 be as easy as it 
 could be made, and 
 that water would 
 pass as rapidly 
 through it as 
 through any orifice 
 of an equal size. But this is not the fact. 
 As the particles approach this orifice, their 
 motion throws them across, and they 
 partly obstruct the opening; it will be 
 seen that they converge toward a point 
 just under the orifice, where the stream will be consider- 
 ably contracted (Fig. 235). If a short tube be inserted 
 into the hole (the head being the same), this crossing of 
 
DISCHARGE OF WATER THROUGH PIPES. 213 
 
 particles will be partly prevented, and the liquid will flow 
 more rapidly. The greatest effect is produced when the 
 tube is twice as long as its diameter (fig. 236). If the 
 tube be enlarged at its upper and lower end, similar to the 
 form of the contracted stream of water in fig. 237, the 
 quantity discharged is greatly increased. 
 
 When water flows down an inclined plane, the same law 
 applies as to the motion of a solid body rolling down a 
 plane. The velocity increases as the square of the distance, 
 and is the same as the velocity of a body falling freely 
 downward from a height equal to the perpendicular height 
 of the plane. Unless the stream, however, is very large, 
 its speed is quickly diminished by the friction of its chan- 
 nel,* until this friction becomes as great as the descending 
 force, after which the motion becomes uniform. Hence 
 the reason that large streams, with an equal degree of de- 
 scent, flow so much more rapidly than small ones, the 
 gravitating force being so much greater that friction has 
 a less retarding effect upon them. 
 
 In pipes which wholly surround the flowing stream, the 
 friction becomes still greater, and the difficulty is only ob- 
 viated by making the pipe of larger dimensions than 
 would otherwise be necessary, so as to allow a free passage 
 of a sufficient quantity of water through the centre of the 
 tube, while a ring or hollow cylinder of water is nearly at 
 rest all around it. The tables in the Appendix exhibit 
 this decreased velocity in tubes of various sizes. 
 
 Lead pipes, for conveying the water of springs under- 
 ground, should commonly be three-fourths of an inch in 
 diameter. Five-eighths will answer where the distance is 
 short and the descent considerable. But with a half-inch 
 pipe, the friction of the sides is so great, compared with 
 the small force of the current, that but little water will 
 flow through it. 
 
 * Which increases as the square of the velocity. 
 
214 MACHINERY IN CONNECTION WITH WATER. 
 
 VELOCITY OF WATER IN DITCHES. 
 
 It is often of great practical utility to know what 
 amount of water may be carried off in draining, or sup- 
 plied in irrigation, by channels of any given size and 
 descent. The following rule will apply to all cases, from 
 the plow-furrow to the mill-race, or even to the large 
 river, and may be used by any boy who understands 
 common arithmetic, and which is illustrated and made 
 plain by the example that follows the rule. 
 
 To ascertain the mean (or average) velocity of water in 
 a straight channel of equal size throughout : 
 
 Let j^the fall in two miles in inches ; 
 
 Let d=th.e hydraulic mean depth ; 
 
 Let -y=the velocity in inches per second ; 
 then the rule is thus expressed : v=0.91 \/fd, or, in plain 
 words, the velocity is equal to the hydraulic mean depth, 
 multiplied by the fall, with the square root of this prod- 
 uct extracted, and then multiplied by 0.91. 
 
 The " hydraulic mean depth-" is found by dividing the 
 cross-section of the channel by the perimeter, or border. 
 The perimeter is the aggregate breadths of the sides and 
 bottom of the channel. 
 
 The rule will be rendered quite plain by an example. 
 Suppose a smooth furrow is cut six inches wide and four 
 inches deep, with perpendicular sides, and that it descends 
 one inch in a rod ; to find the quantity of water that will 
 flow through it. One inch fall in a rod is 320 inches in a 
 mile, or 640 in two miles. The perimeter in contact with 
 the water will be six inches on the bottom and four 
 inches in each side = 14 inches. The area of the cross- 
 section will be six times 4 = 24, which, divided by 14, 
 the perimeter, gives 1.7 = the hydraulic mean depth. 
 Then, by applying the preceding rule : 
 
 v =0.91 V 640 x 1.7, or v=0.91 x 33=30 inches, is the ve- 
 
LEVELING INSTRUMENTS. 215 
 
 locity per second, which -would be about three gallons per 
 second, or three hogsheads per minute. 
 
 An open ditch, therefore, with smooth sides, conveying 
 a stream of this size, would carry off, in one hour, from 
 an acre of land, all the water which might fall by half an 
 inch of rain, during the wet season ; for half an inch of 
 rain would be one hundred and eighty hogsheads per 
 acre, which would pass off in one hour ; or it would sup- 
 ply in one hour, by the process of irrigation, as much 
 water as a heavy shower of half an inch. Where the 
 descent is greater, the increased quantity may be readily 
 calculated by the rule given. The capacity of smooth- 
 sided underground channels may be determined in the 
 same way ; but if built of rough stones, great allowance 
 must be made, as they will retard the flow of water. 
 
 In common practice, too, even with straight, open 
 ditches, the velocity will be much diminished by the 
 rough sides. 
 
 LEVELING INSTRUMENTS. 
 
 The simplest mode of leveling, or ascertaining the slope 
 for ditches, is to cut a few yards of the ditch, so that wa- 
 ter may stand in it, and then to set two sticks perpendicu- 
 larly, both rising to an equal height above the surface. 
 
 Fig. 238. 
 
 * Simple Method cf Talcing Levels. 
 
 The sticks should be measured at equal distances from 
 the top downward, and marked, and then pressed into 
 the earth, till the water reaches the mark. The level may 
 then be determined with much accuracy by " sighting " 
 over the tops of these sticks. Fig. 238 exhibits this ar- 
 rangement. The shorter the sticks, and the longer the 
 piece of water, the less will be the liability to error. 
 
216 
 
 MACHINERY IN CONNECTION WITH WATEE. 
 
 A leveling instrument for general use, sufficiently ac- 
 curate for all common purposes, may be made in the fol- 
 lowing manner : — Pro- 
 
 ■jjgh 
 
 Fig. 239. 
 
 a 
 
 I 
 
 i 
 
 ^r 
 
 cure a mason s or car- 
 penter's spirit-level, (a, 
 fig. 239) fasten it to the 
 upper side of a straight 
 bar of wood, and on the 
 ends of this bar secure 
 small, upright pieces of 
 tin plate, 5, b, having 
 openings cut in the 
 centre. Horizontally 
 across these openings, 
 draw very fine wire, 
 which shall be exactly 
 f at equal heights above 
 
 each end of the bar of wood, to adjust which, one should 
 be capable of sliding, and be screwed or wedged to its 
 place at pleasure. The bar is placed on a common com- 
 pass staff, as shown in 
 the cut, turning at the 
 ball and socket, below 
 the spirit level. A tripod 
 (fig. 240) is better, if it 
 can be had. A small 
 spirit-level should be se- 
 cured across the bar, so 
 that it may be adjusted 
 both ways. When the 
 bar is made perfectly 
 level, as shown by the air-bubble, by sighting through at 
 the two wires, the levelness or descent of the land may be 
 determined. 
 
 To ascertain whether these threads are both of equal 
 heights above the bar, let a mark be made where they in- 
 
 Fig. 240. 
 
ARCHIMEDEAN SCREW. 
 
 21? 
 
 tersect some distant object ; then reverse the instrument, 
 or turn it end for end., and observe whether the threads 
 cross the same mark. If they do, the instrument is cor- 
 rect ; but if they do not, then one of the sights must be 
 raised or lowered until it becomes so. 
 
 In laying out canals and rail-roads, where extreme ac- 
 curacy is needed, the spirit-level, attached to a telescope, 
 is used. So great is the perfection of this instrument, 
 that separate lines of levels have been run with it for six- 
 ty miles, without varying two-thirds of an inch for the 
 whole distance. 
 
 The use of a cheap and simple instrument to determine 
 the position and descent of ditches with ease and preci- 
 sion, before commencing with the spade, will save a vast 
 amount of the trouble and expense which those often 
 meet with whose only method is to " cut cmd try" 
 
 HYDRAULIC MACHINES. 
 
 ARCHIMEDEAN SCREW. 
 
 Machines for raising water are of frequent use on every 
 farm. One of the simplest contrivances, in principle, for 
 this purpose, is the Screw of Archimedes. It may be 
 
 Fig. 241. 
 
 The Screw of Archimedes 
 
 easily made by winding a lead tube around a wooden 
 cylinder or rod (fig. 241), in the form of a screw. 
 1Q 
 
 When 
 
218 
 
 MACHINERY IN CONNECTION WITH WATER. 
 
 placed iii an inclined position, with one end in water, and 
 made to revolve, the water resting at the lower side of 
 each turn of the screw is gradually carried from one end 
 to the other, and discharged at the upper extremity. Its 
 simplicity and small liability to get out of order render 
 the Archimedean screw sometimes useful where water is 
 to be raised from an open stream to a short distance, as 
 for irrigation, the motion being easily imparted to it by 
 means of a small water-wheel, driven by the stream. 
 
 PUMPS. 
 
 Great improvement has been made in the common 
 
 Tie:. 242. 
 
 Common Pump : b, lower or fixed 
 valve, G, piston with valve, a, 
 opening upward; D d } piston- 
 rod ; F, spout, 
 
 pump for farms within a few years. 
 The best cast-iron pumps, made 
 almost wholly of this metal, ex- 
 ceed in durability and ease of 
 working those formerly con- 
 structed of wood, and excel others 
 in cheapness. Fig. 242 exhibits 
 the working of the common pump, 
 the water first passing through 
 the fixed valve below, and then 
 through the one in the piston ; 
 both opening upward, it cannot 
 flow back without instantly shut- 
 ting them. The water is driven 
 up by the pressure of the at- 
 mosphere, explained in the next 
 chapter. 
 
 Fig. 243 is an iron cistern pump, 
 showing; the mode of bolting it to 
 the floor or platform, and rep- 
 resenting, also, its neat and com- 
 pact form, occupying but little 
 space at one side, or in the corner 
 of a kitchen, over the cistern. 
 
PUMPS. 
 
 219 
 
 Fisr. 244. 
 
 Fig. 244 represents a cistern or well pump, so constructed 
 that the working parts are about 20 inches below the plat- 
 form, or base of the pump, and it is therefore well adapt- 
 ed for outdoor work. If the well 
 or cistern is kept covered tight, 
 the pump will not freeze below 
 the platform. It will succeed 
 in any well not over twenty feet 
 deep, and by means of its 
 various couplings may be made to 
 draw water in a horizontal or in- 
 clined position, provided the whole 
 height is not much over twenty feet. 
 
 Fig. 243. 
 
 Cistern Pump. 
 
 Non-freezing Pump. 
 
 An excellent deep-well pump, made by Cowing & Co., 
 of Seneca Falls, N". Y., is represented by fig. 245 ; the 
 working part, being placed at the bottom of the well, is 
 adapted to any depth of water, the rod working safely 
 within the pipe. The lower part of the cylinder is fur- 
 nished with a strainer, and is plugged at the bottom, to 
 
220 MACHINERY IX CONNECTION WITH WATER. 
 
 Fig. 246. Fijr. 245. 
 
 Drive Pump. 
 
 prevent the ingress of sand and i 
 mud. The connecting pipe between & 
 the cylinder at the bottom and the 
 standard at the top is wrought or , 
 galvanized iron. The pump, of *$0. 
 course, needs bracing, to prevent 
 swinging when worked. 
 
 Drive Pumps. — Fig. 246 rep- 
 resents the new mode of making 
 wells, by simply driving into the 
 earth common iron gas-pipe, pointed -jSSljIjfl 
 at the lower end, and perforated at x5r?8 
 the sides, near the lower extremity, Deep-wen ramp. 
 
DRIVE PUMPS. 
 
 221 
 
 for the ingress of water — thus obviating entirely the cost 
 and labor of digging wells. If driven through a subter- 
 ranean spring, a stratum of water, or a wet layer of sand or 
 gravel, it is obvious that the water will immediately flow 
 through the perforations into the pipe ; and, by attaching a 
 good pump to the pipe and pumping for a time, all the par- 
 ticles of sand and fine gravel will be drawn out ; and the 
 cavity thus formed around the perforations will remain filled 
 with pure water. These tubes and pumps are admirably 
 adapted to localities where large beds of wet gravel exist 
 fifteen or twenty-five feet below ; and, in fact, to all soils 
 where large stones are not abundant. Where these occur, 
 the pipe must be withdrawn, and tried in a new place, 
 until success is attained. 
 
 In the Chain Pump, a partial cross-section of whioh is 
 
 Figr. 247. 
 
 Fie:. 24S. 
 
 Chain Pump 
 Section. 
 
 liotary Pump, for Barrels, etc. 
 here shown, (fig. 247), the chain is made to revolve rapid- 
 ly on the angular wheel by means of a winch attached to 
 
222 
 
 MACHINERY IN CONNECTION WITH WATEK. 
 
 
 
 Fig. 249. 
 
 
 ■TO 
 
 
 g 
 
 i 
 
 1 11 
 
 the upper one, and being furnished with a regular succes- 
 sion of metallic discs, which 
 nearly fit the bore in the tube, 
 «, the water is carried up in 
 large quantities. When the 
 motion is discontinued, the 
 water settles down again into 
 the well, and consequently 
 this pump is not liable to 
 accident by freezing. By 
 sweeping rapidly through the 
 water, it preserves it in better 
 condition, and prevents stag- 
 nation. The friction being 
 very small, it will last a long 
 time without wearing out. 
 
 Rotary Pumps. — A succes- 
 sion of cavities made in the 
 exterior of a short cylinder 
 receive the water from the 
 pump-tube below, and force 
 it away into the elevating 
 tube. When driven fast, it 
 pumps with great rapidity. 
 It possesses this advantage 
 over the common pump, that 
 the motion being continuous, 
 no force is lost by repeatedly 
 checking the momentum. In 
 the figure on the preceding 
 page, the pump is represented 
 as inserted in a barrel of oil, 
 which is to be emptied into 
 the reservoir above, and is 
 Suction and Forcing-pump. worked by hand. Larger 
 
 rotary pumps are driven by horse and steam power. 
 
TURBINE WATER-WHEELS. 
 
 223 
 
 Suction and Forcing-Pump. — The accompanying cut (fig. 
 249) represents a suction and forcing-pump combined in one, 
 for the purpose of drawing water from a well or cistern, 
 and forcing it to tanks in upper stories, or throwing water 
 into upper rooms in case of fire. By lengthening the rod, 
 the working parts may be placed at the bottom of a deep 
 well, and the whole used as a deep well pump. 
 
 TURBINE WATER-WHEELS. 
 
 The large wooden wheels formerly used for the appli- 
 cation of water power to mills and other machinery are 
 rapidly giving place to iron Turbine wheels. Overshot 
 wheels, the best kind formerly employed, were turned by 
 the weight of the water, the whole of which was held in 
 the slowly descending buckets of the wheel. Turbine 
 wheels do not hold the water, but merely receive and im- 
 part the force of the rushing current, the water being 
 held by the flume above. Hence, a turbine wheel of 
 quite small size may impart to machinery nearly the 
 whole force of a powerful current of water. 
 
 Turbine wheels are placed in a horizontal position, with 
 
 vertical axes. Being 
 under water, they never 
 freeze ; and they are not 
 impeded by back-water 
 when a flood occurs. 
 There are two principal 
 kinds among those in 
 common use, — those, 
 like the Reynolds wheel, 
 which have a single 
 opening at the side, 
 through which the wa- 
 ter is admitted; and such as the Leffel and Van de Water 
 wheels, into which the water is admitted through several 
 openings around them. 
 
 Fisr. 250. 
 
 Section of Reynolds' Wieel. 
 
224 
 
 MACHINERY IX CONNECTION WITH "WATER. 
 
 Fig. 252. 
 
 View of Reynolds' Turbine =S? 
 Wheel. 
 
 Fig. 250 is a section of the Reynolds wheel ; (r, the 
 Fig. 251. gate for admitting the 
 
 water through the hori- 
 zontal shute from the 
 flume ; A, A, the circu- 
 lar passage for the water, 
 which is gradually di- 
 minished in volume as it 
 strikes the buckets or 
 blades, B,B^ and escapes 
 through the bottom and 
 top of the wheel. The 
 arrows show the currents, and the curved dotted lines the 
 openings through which the Fig. 253. 
 
 water escapes — the curved 
 arrows exhibiting the re- 
 bounding of the current 
 against the blades, before 
 passing out through the is- 
 sues. Fig. 251 is an exterior 
 view of the wheel, showing 
 the gate for the admission 
 of the water ; and fig. 252 
 
 represents the shaft and 
 
 Fig. 254. Section of Van de Water Wheel. 
 
 buckets separate. 
 
 Fig. 253 is a section of 
 the Yan de Water wheel, 
 6r, 6r, 6r, 6r, being the 
 gates for admitting wa- 
 ter, and J?, _Z?, the buck- 
 ets — the arrows rep- 
 resenting the entering 
 currents. H shows, by 
 dotted lines, the position 
 Van de Water wheel. of one of the gates when 
 
 closed. The water, after entering the buckets, passes out 
 
TURBINE WATER-WHEELS. 225 
 
 below, where the blades are curved backwards, to receive 
 all the force of the escaping water. Fig. 254 is a view of 
 this wheel, showing the admission gates, and the wheel at 
 the top, for opening and shutting the gates at one movement. 
 
 The Reynolds wheel is placed under water, outside the 
 flume, and the current admitted at the side, as already 
 stated. The Van de Water wheel is placed within, and 
 on the bottom of the flume, in the floor of which a circu- 
 lar hole is cut, through which the water escapes. Both 
 are excellent wheels, and are among those most exten- 
 sively manufactured in the country — the former by George 
 Tallcot, of New York, and the latter by the inventor, H. 
 Van de Water, of Attica, 1ST. Y. 
 
 Turbine wheels, of the best construction, do not lose 
 more than one-seventh or one-eighth of the whole descend- 
 ing force of the water. Hence, the power of any stream 
 may be determined beforehand with much accuracy, if 
 the descent or head and the number of cubic feet of wa- 
 ter per minute are known. It has been already shown in 
 this work, that a single horse-power is equal to lifting 
 33,000 lbs. one foot, per minute. This is equivalent to 
 raising 530' cubic feet of water to the same height, or 53 
 cubic feet, ten feet high. A stream, then, which falls 10 
 feet, and discharges 53 cubic feet in a minute, or nearly 1 
 per second, has an inherent force of one horse-power. 
 Add one-seventh, making it about 60 cubic feet, and we 
 have the size of a stream for one horse-power, at ten feet 
 fall. Twenty feet descent would double the power, forty, 
 quadruple it, and so on; and a similar increase result 
 from employing a larger stream. As examples, a small 
 wheel, seven or eight inches in diameter, will be sufficient 
 for such a purpose. One of this size, with 20 feet head, 
 and discharging 70 or 80 cubic feet of water per minute, 
 will possess about three horse-power ; and with forty feet 
 head, requiring over 100 cubic feet per minute, it will 
 have a power of eight or nine horses. 
 10* 
 
226 MACHINERY IN CONNECTION WITH WATER. 
 
 The simple rule given in the second paragraph of the 
 present chapter, for determining the velocity of a current 
 of water spouting out under any given head, will enable 
 any one who understands arithmetic to calculate the 
 proper speed of a turbine wheel, which varies with the 
 head and the diameter of the wheel. It is found that the 
 buckets or blades should move with about two-thirds the ve- 
 locity of the current as it rushes from the flume ; hence, 
 as an example, under a head of 16 feet, which drives out 
 a stream about 22 feet per second, the exterior of the 
 turbine wheel should move about 14 or 15 feet per second. 
 If 1 foot in diameter, it should therefore revolve five 
 times per second ; or, if 2-^- feet in diameter, only twice 
 per second. Other examples may be readily computed. 
 
 There are occasional opportunities for employing water 
 power for driving farm machinery — as thrashing ma- 
 chines, mills for grinding feed, corn shellers, wood saws, 
 straw cutters, etc., by bringing streams along hill-sides, 
 or over bluffs ; in which cases, turbine wheels would be 
 cheaper than steam-engines, and require neither food nor 
 fuel. The water of small streams might be saved in dams 
 or ponds, giving a power of five or six horses for 
 one day in each week for grinding, thrashing, and other 
 purposes. 
 
 THE WATER-RAM. 
 
 One of the most ingenious and useful machines for ele- 
 vating water is the Water-ram. It might be employed 
 with great advantage on many farms, were its principle 
 and mode of action more generally understood. By means 
 of a small stream, with only a few feet fall, a current of 
 water may be driven to an elevation of 50 feet or more 
 above, and conveyed on a higher level to pasture-fields 
 for irrigation, to cattle-yards for supplying drink to 
 domestic animals, or to the kitchens of dwellings for cu- 
 linary purposes. 
 
THE WATER- RAM. 
 
 227 
 
 Fijr. 255. 
 
 Its power depends on the momentum of the stream. 
 Its principal parts are the reservoir, or air-chamber, A, 
 (fig. 255), the supply pipe, J5, and the discharge pipe, C. 
 The running stream rushes down the drive, or supply- 
 pipe, _Z?, and, striking the waste valve, i>, closes it. The 
 stream being thus suddenly checked, its momentum opens 
 the valve, J£, upward, and drives the water into the reser- 
 voir, A, until the air within, being compressed into a 
 smaller space by its elasticity, bears down upon the water, 
 and again closes the valve, E. The water in the supply- 
 pipe, _Z?, has, by this 
 time, expended its mo- 
 mentum, and stopped 
 running ; therefore the 
 valve, D, drops open 
 again, and permits it to 
 escape. It recommences 
 running, until its force 
 again closes the waste 
 valve, D, and a second 
 portion of water is driven into the reservoir as be- 
 fore, and so it repeatedly continues. The great force of 
 the compressed air in the reservoir drives the water up 
 the discharge-pipe, C, to any required height or distance. 
 
 The mere weight of the water will only cause it to rise 
 as high as the fountain head ; but like the momentum of 
 a hammer, w T hich drives a nail into a solid beam, which a 
 hundred pounds would not do by pressure, the striking 
 force of the stream exerts great power. 
 
 The discharge pipe, (7, is usually half an inch in diame-" 
 ter, and the supply-pipe should not be less than an inch 
 and a fourth. A fall of three or four feet in the stream, 
 with not less than half a gallon of water per minute, with 
 a supply-pipe forty feet long, will elevate water to a 
 height as great as the strength of common half-inch lead 
 
 Water-ram. 
 
228 MACHINERY IN CONNECTION WITH WATEE. 
 
 pipe will bear.* The greater the height, in proportion to 
 the fall of the stream, the less will be the quantity of wa- 
 ter elevated, as compared with the quantity flowing in 
 the stream, or escaping from the waste valve. 
 
 H. L. Emery gives the following rule for determining 
 the quantity of water elevated from a stream : — Divide 
 the elevation to be overcome by the fall in the drive-pipe, 
 and. the quotient will be the proportion of water, (passing 
 through the drive-pipe), which will be raised, — deducting, 
 also, for waste of power and friction, say one-fourth the 
 amount. Thus, with 10 feet fall, and 100 feet elevation, 
 one-tenth of the water would be raised if there were no 
 friction or loss ; but, deducting, say one-fourth for these, 
 seven and a half gallons in each hundred gallons 
 would be raised, the rest escaping, or being required to 
 accomplish this result. Or, if the fall of the water in the 
 supply-pipe be 3 feet, and the elevation required in the 
 discharge-pipe be 15 feet, about one-seventh part of all 
 the water will be elevated to this height of 15 feet. But 
 if the desired height be 30 feet, then only about one-four- 
 teenth part of the water will be raised ; and so on in 
 about the same ratio for different heights. A gallon per 
 minute from the spring would elevate six barrels five 
 times as high as the fall, in twenty-four hours, and at the 
 same rate for larger streams. With a head of 8 or 10 
 feet, water may be driven up to a height of 100, or even 
 150 feet, provided the machine and pipes are strong 
 enough. The best result is obtained when the length of 
 the drive-pipe and the momentum it produces are just suf- 
 ficient to overcome the reaction caused by the closing of 
 
 * When water is raised to a considerable elevation by means of the 
 water-ram, the reservoir must possess great strength. If the height be 
 100 feet, the pressure, as shown on a former page, is about forty-four 
 pounds to the square inch. With an internal surface, therefore, of only 
 2 square feet, the force exerted by the column of water, tending to 
 burst the reservoir, would be equal to more than twelve thousand 
 pounds. 
 
THE WATER-RAM. 229 
 
 the waste valve at each pulsation, and prevent the current 
 of water from being thrown backward or up the drive- 
 pipe ; hence, the greater the disproportion between the 
 foil and the required elevation, the longer or larger must 
 be the drive-pipe, in order to obtain sufficient momentum. 
 A descent of only a foot or two is sufficient to raise water 
 to moderate elevations, but the drive-pipe should be of 
 large bore. This pipe should always be very nearly 
 straight, so that the water, by having a free course, may 
 acquire sufficient momentum to compress the air in the 
 ram, and push the water up the discharge-pipe. Water 
 may be carried to a distance of a hundred rods or more, 
 but as there is some friction in so long a discharge-pipe, 
 a greater force is required than for short distances. The 
 discharge-pipe should, therefore, be larger, as the length 
 is increased. Half an inch diameter is a common size, 
 but long pipes may be five-eighths or three-fourths ; and, 
 when practicable, it is more economical to reach an eleva- 
 tion with a short and strong pipe, and to use a lighter 
 and weaker one for the upper part. A pit, lined with 
 brick or smooth stone, for placing the ram, protects it 
 from freezing ; and both pipes should be under ground 
 for the same reason. The supply or drive-pipe is usually 
 40 to 50 feet long ; but where the fall is 8 or 10 feet, it 
 should be sixty or seventy feet. 
 
 Unlike a pump, there is no friction or rubbing of parts 
 in the water-ram, and, with clean water, it will act for 
 years without repairs, continuing through day and night 
 its constant and regular pulsations, unaltered and unob- 
 served. A small quantity of sand, or of dead grass or 
 other fibre, in the water, will be liable to obstruct the 
 valves, and render frequent attention necessary. 
 
 WATER-ENGINES, 
 
 including those for extinguishing fires and for irrigating 
 gardens, are constructed on a principle quite similar to 
 
230 MACHINERY IN CONNECTION WITH WATEK. 
 
 Fiff. 25G. 
 
 Fig. 257. 
 
 Garden-engine 
 that of the water-ram. In- 
 stead, however, of compress- 
 ing the air, as in the ram, 
 by the successive strokes of 
 a column of running water, 
 it is accomplished by means 
 of a forcing-pump, driving 
 the water into the reservoir, 
 from which it is again ex- 
 pelled with great power, by 
 means of the elasticity of 
 the compressed air. Fig. 256 
 represents a garden-engine, 
 movable on wheels, which 
 may be used for watering 
 gardens, washing windows, 
 or as a small fire-engine. Fig. 
 257 is another, of smaller 
 size, for the same purposes, 
 
 and in a neat and compact cylindrical Garden-engbie. 
 
 form, the working part being within the cylindrical case. 
 
THE FLASH-WHEEL, FOIi IIAISING WATER. 
 
 2S1 
 
 THE FLASH-WHEEL 
 
 is employed with great advantage where the quantity of 
 water is large, and is to be raised to a small height, as in 
 draining marshes and swamps. It is like an undershot 
 wheel with its motion reversed; in iig. 258 the ar- 
 rows show the direction of the current when driven up- 
 ward. It must, of course, be made to fit the channel 
 closely, without touching and causing friction. In its best 
 form, its paddles incline backward, so as to be nearly up- 
 
 Fiff. 258. 
 
 Flash or fen wheel for raising water rapidly short distances. 
 
 right at the time the water is discharged from them into 
 the upper channel. It has been much used in Holland, 
 where it is driven by wind-mills, for draining the surface- 
 water off from embanked meadows. In England, it has 
 been driven by steam-engines ; and in one instance, an 
 eighty-horse-power engine, with ten bushels of coal, raised 
 9,840 tons of water six feet and seven inches high, in an 
 hour. This is equal to more than 29,000 lbs. raised one 
 foot per minute by each horse-power, showing that very 
 little force is lost by friction in the use of the flash-wheel. 
 
232 MACHINERY IN CONNECTION WITH WATER. 
 
 WAVES. 
 
 NATURE OE WAVES. 
 
 An inverted syphon, or bent tube, like that shown in 
 fig. 259, may be used to exhibit the F >s- 259. 
 
 principle on which depends the motion 
 of the waves of the sea. The action of 
 the waves on shores and banks, and the 
 inroads which they make upon farms 
 situated on the borders of lakes and 
 large rivers, present an interesting sub- 
 ject of inquiry. 
 
 If the bent tube (fig. 259) be nearly filled with water, 
 and the surface be driven down in one arm by blowing 
 suddenly into it, the liquid will rise in the other arm. 
 The increased weight or head of this raised column will 
 cause it to fall again, its momentum carrying it down below 
 a level, and driving the water up the other arm. The 
 surfaces will, therefore, continue to vibrate until the force 
 is spent. The rising and falling of waves depend on a 
 similar action. The wind, by blowing strongly on a por- 
 tion of the water of the lake or sea, causes a depression, 
 and produces a corresponding rise on the adjacent surface. 
 The raised portion then falls by its weight, with the add- 
 ed force of the wind upon it, until the vibrations increase 
 into large waves. 
 
 THE WATER NOT PROGRESSIVE. 
 
 The waves thus produced have a progressive motion 
 (for reasons to be presently shown), as every one has ob- 
 served. A curious optical deception attending this ad- 
 vancing motion has induced many to believe that the 
 water itself is rolling onward ; but this is not the fact. 
 The boat which floats upon the waves is not carried for- 
 ward with them 5 they pass underneath, now lifting it on 
 
WATER OF WAVES NOT PROGRESSIVE. 233 
 
 their summits, and now dropping it into the hollows 
 between. The same effect may be observed with the wa- 
 ter-fowl, which sits upon the surface. It often happens, 
 indeed, that the waves on a river roll in an opposite di- 
 rection to the current itself. 
 
 If a cloth be laid over a number of parallel rollers, so 
 far apart as to allow the cloth to fall between them, and a 
 progressive motion be then given to them, the cloth remain- 
 ing stationary, a good representation of waves will be 
 afforded, and the cloth will appear to advance ; or if a 
 strip of cloth be laid on a floor, repeated jerks at one end 
 will produce a similar illusion. 
 
 It is only the form of the wave, and not the water 
 which composes it, which has the onward motion. Let 
 the dark line in fig. 260 represent the surface of the water. 
 
 Fig. 2G0. 
 A 
 
 B 
 
 A is the crest of one of the waves, and being higher than 
 the surface at i?, it has a tendency to fall, and B to rise. 
 But the momentum thus acquired carries these points so 
 far that they interchange levels. The same change takes 
 place with the other waves, and the dotted line shows the 
 newly formed surface as the water thus sinks in one place 
 and rises in another. The same process is again repeat- 
 ed, and each wave thus advances further on, and its pro- 
 gressive motion is continually kept up. 
 
 BREADTH AND VELOCITY OF WAVES. 
 
 Each wave contains at any one moment particles in all 
 possible stages of their oscillation ; some rising, and some 
 falling ; some at the top, and some at the bottom ; and 
 the distance from any row of particles to the next row 
 that is in precisely the same stage of oscillation is called 
 
234 MACHINERY IN CONNECTION WITH WATER. 
 
 breadth of the wave, that is, the distance from crest to 
 crest, or from hollow to hollow. 
 
 There is a striking similarity between the rising and 
 falling of waves and the vibrations of a pendulum, and it 
 is a very interesting and remarkable fact, that a wave al- 
 ways travels its own breadth in precisely the same time 
 that a pendulum, whose length is equal to that breadth, 
 performs one vibration. Thus, a pendulum 39|- inches 
 long beats once in each second, and a wave whose breadth 
 is 39J inches travels that breadth in one second. The 
 length of a pendulum must be increased as the square of 
 the time for its vibrations ; that is, to beat but once in 
 two seconds, it must be four times as long as for one 
 second ; to beat once in three seconds, it must be nine 
 times as long, and so on. In the same way, waves which 
 travel their breadth in two seconds are four times as wide 
 as those traveling their breadth in one second ; and thus 
 their breadth, and consequently their speed, increases as 
 the square of the time. Large waves, therefore, roll on- 
 ward with far greater velocity than small ones. If only 
 thirty-nine inches wide, they move about two and a quar- 
 ter miles an hour, and pass once each second ; if 
 
 13 feet wide, they move 4% miles an hour, passing once in 2 seconds. 
 
 52 do. do. 9 do. do. 4 do. 
 
 209 do. do. 18 do. do. 8 do. 
 
 830 do. do. 36 do. do. 16 do. 
 
 Although the water itself does not advance where there 
 is much depth, yet when it reaches a shore or beach, the 
 hard and shallow bottom prevents it from falling or sub- 
 siding, and it then rolls onward with a real progressive 
 motion from the momentum it has acquired, breaks into 
 foam, and lashes the earth and rocks. The sea billows 
 are sometimes twenty-five feet in elevation,* and when 
 these advance upon a stranded ship on a lee shore, with 
 
 * No authentic measurement gives the perpendicular height of waves 
 more than twenty-five feet. 
 
PREVENTING THE INROAD OF WAVES. 235 
 
 the speed of a locomotive, their effects are in the highest 
 degree appalling; and iron bolts are snapped, and massive 
 timbers crushed beneath their violence. 
 
 PREVENTING THE INROAD OP WAVES. * 
 
 To prevent the inroads of lake waves upon land, the 
 remedies must vary with circumstances. The difficulty 
 would be small if the water always stood at the same 
 height. The greatest mischief is usually -done when they 
 rise over the beach of sand and gravel which they have 
 beaten for centuries. Wooden bulwarks soon decay. 
 Where loose stones can be had in large quantities, form- 
 ing sloping rip-rap walls, they may be cheapest ; but they 
 are not unfrequently placed too near low-water mark to 
 protect the banks. Substances which offer a gradual im- 
 pediment to the waves are often quite effectual, though 
 not formidable in themselves. It is curious to observe how 
 so slender a plant as the bulrush, growing in water several 
 feet deep, will destroy the force of waves. If it grew 
 only near the shore, where the water has progressive mo- 
 tion, it would soon be dashed in heaps on the beach. 
 Parallel hedge-rows of the osier willow, protected by a 
 wooden barrier until well grown and established would, 
 
 in many cases, prove efficient. 
 
 Stones and timber bulwarks are often made needlessly 
 F .„ 261 liable to injury by 
 
 being built nearly 
 perpendicular, and 
 the waves break 
 suddenly, and w T ith 
 full force, like the 
 blows of a sledge against them. A better form is shown 
 in fig. 261, where a slope is first presented, to weaken their 
 force without imposing a full resistance, and their 
 strength is gradually spent as they rise in a curve. A 
 
236 MACHINERY IN CONNECTION WITH WATER. 
 
 more gradual slope than the figure represents would be 
 still better. It is on this principle that the stability of the 
 world-renowned Eddystone light-house depends. The 
 base spreads out in every direction, like the trunk of a 
 tree at the roots ; and although the spray is sometimes 
 dashed over its lofty summit by the violence of the storm, 
 it has stood unshaken on its rocky base far out in the sea, 
 against the billows and tempests, for nearly a century. 
 
 An instance occurred many years ago in England, where 
 the superiority of knowledge over power and capital 
 without it was strongly exemplified. The sea was mak- 
 ing enormous breaches on the Norfolk and Suffolk coast, 
 and inundated thousands of acres. The government com- 
 missioners endeavored to keep, it out by strong walls of 
 masonry and breakwaters of timber, built at great ex- 
 pense ; but they were swept away by the fury of the bil- 
 lows as fast as they were erected. A skillful engineer 
 visited the place, and, with much difficulty, persuaded 
 them to adopt his simple plan. Observing the slope of 
 the beach on a neighboring shore, he directed that suc- 
 cessive rows of fagots or brush be deposited for retaining 
 the sand, which was carted from the hills, forming an em- 
 bankment with a slope similar to that of the natural 
 beach. Up this slope the waves rolled, and became grad- 
 ually spent as they ascended, till they entirely died away. 
 The breach was effectually stopped, and this simple struc- 
 ture has ever since resisted the most violent storms of 
 the German Ocean. 
 
 CONTENTS OF CISTERNS. 
 
 Connected with the subject of hydraulics is the collec- 
 tion and security of water falling upon roofs, in all cases 
 where a deficiency is felt by farmers in the drought of 
 summer. The amount which falls upon most farm-build- 
 ings is sufficient to furnish a plentiful supply to all the 
 
CONTENTS OP CISTERNS. 237 
 
 domestic animals of the farm when other supplies fail, if 
 cisterns large enough to hold it were only provided. 
 Generally speaking, none at all are connected with barns 
 and out-buildings, and even when they are furnished, 
 they are usually so small as to allow four-fifths of the 
 water to waste. 
 
 If all the rain that descends in the Northern States of 
 the Union should remain upon the surface, without sink- 
 ing in or running off, it would form, each year, a depth 
 of about three feet. Every inch that falls upon a roof 
 yields two barrels for each space ten feet square; and 
 seventy-two barrels a year are yielded by three feet of 
 rain. A barn thirty by forty feet supplies annually 
 from its roof eight hundred and sixty-four barrels, or 
 enough for more than two barrels a day for every day in 
 the year. Many farmers have in all five times this 
 amount of roof, or enough for twelve barrels a day, year- 
 ly. If, however, this water were collected, and kept for 
 the dry season only, twenty or thirty barrels daily might 
 be used. 
 
 In order to prevent a waste of water on the one hand, 
 and to avoid the unnecessary expense of too large cisterns, 
 their contents should be determined beforehand by calcu- 
 lation. 
 
 RULE FOR DETERMINING THE CONTENTS. 
 
 A simple rule to determine the contents of a cistern, 
 circular in form, and of equal size at top and bottom, is 
 the following :— Find the depth and diameter in inches; 
 square the diameter, and multiply the square by the deci- 
 mal .0034, which will give the quantity in gallons* for one 
 inch in depth. Multiply this by the depth, and divide by 
 
 * This is the standard gallon of 231 cubic inches. The gallon of the 
 State of New York contains 221.18-i cubic inches, or 6 pounds at its 
 maximum density. 
 
238 MACHINERY IN CONNECTION WITH WATER. 
 
 31^-, and the result will be the number of barrels the cis- 
 tern will hold. 
 
 For each foot in depth, the number of barrels answer- 
 ing to the different diameters are, 
 
 For 5 feet diameter 4.66 barrels. 
 
 6 " 6.71 " 
 
 7 " 9.13 u 
 
 8 " 11.93 " 
 
 9 " 15.10 " 
 
 10 " 18.65 " 
 
 By the rule above given, the contents of barn-yard 
 cisterns and manure tanks may be easily calculated for any 
 size whatever. 
 
 The size of cisterns should vary according to their in- 
 tended use. If they are to furnish a daily supply of 
 water, they need not be so large as for keeping supplies 
 for summer only. The average depth of rain which falls 
 in this latitude, although varying considerably with season 
 and locality, rarely exceeds seven inches for two months. 
 The size of the cistern, therefore, in daily use, need never 
 exceed that of a body of water on the whole roof of the 
 building, seven inches deep. To ascertain the amount of 
 this, multiply the length by the breadth of the building, 
 reduce this to inches, divide the product by 231, and the 
 quotient will be gallons for each inch of depth. Multiply- 
 ing by 7 will give the full amount for two months' rain 
 falling upon the roof. Divide by 31^-, and the quotient 
 will be barrels. This will be about fourteen barrels for 
 every surface of roof ten feet square when measured hori- 
 zontally. Therefore, a cistern for a barn 30 by 40 feet 
 should hold one hundred and sixty-eight barrels ; that is, 
 as large as one ten feet in diameter, and nine feet deep. 
 Such a cistern would supply, with only thirty inches of 
 rain yearly, no less than six hundred and thirty barrels, 
 or nearly two a day. 
 
 Cisterns intended only for drawing from in times of 
 drought, to hold all the water that may fall, should have 
 about three times the preceding capacity. 
 
PART III. 
 
 MACHINERY IN CONNECTION WITH AIR. 
 
 CHAPTER I. 
 
 PRESSURE OF AIR. 
 
 Pneumatics treats of the me- 
 chanical properties of the air. 
 
 The actual weight of the air 
 may be correctly found by weigh- 
 ing a strong glass vessel furnished 
 with a stop-cock, a (fig. 262), after 
 the air has been withdrawn from 
 it by means of an air-pump. Let 
 it be accurately balanced by 
 weights in the opposite scale; 
 then turn the stop-cock and admit 
 the air, and it will immediately 
 descend, as shown in the figure. 
 The weight of the admitted air 
 may be ascertained by adding 
 weights until it is again balanced. 
 
 Fi<r. £02. 
 
 Balance for Weighing Air, 
 
 HEIGHT AND WEIGHT OF THE ATMOSPHERE. 
 
 The atmosphere which covers the earth extends upward 
 
 to a height of about fifty or sixty miles. At the surface 
 
 of the earth the air is about eight hundred times lighter 
 
 than the water, and the higher we ascend, the rarer or 
 
 239 
 
240 
 
 MACHINERY IN CONNECTION WITH AIR. 
 
 lighter it becomes, from the diminished pressure of the 
 weight above. At seven miles high, it is four times light- 
 er than at the surface ; at twenty-one miles, it is sixty- 
 four times lighter ; and at fifty miles, about twenty thou- 
 sand times lighter. At this height it ceases to refract the 
 rays of the sun so as to render it visible at the earth's sur- 
 face ; but if it decreases at the same rate upward, at a 
 hundred miles high it must be nearly a thousand million 
 times rarer than at the earth. 
 
 If the atmosphere were uniformly of the same density, 
 with its present weight, it would reach only five miles 
 high. Although so much lighter than water, yet, from 
 its great height, it presses upon the surface of the earth 
 as heavily as a depth of thirty-three feet of water. This 
 is nearly equal to fifteen pounds on every square inch, or 
 more than two thousand pounds to the square foot. This 
 enormous weight would instantly crush us, did not air, 
 like liquids, press in every direction, so that the upward 
 exactly counterbalances the downward pressure, and the 
 air within the body counteracts that without. 
 
 The weight of the atmosphere is strikingly shown by 
 
 means of an air- 
 pump, which pumps 
 the air from a glass 
 vessel, placed mouth 
 downward upon the 
 brass plate of the 
 machine (fig. 263). 
 When the air is 
 pumped out, and the 
 upward or counter- 
 balancing air remov- 
 ed, so heavy is the 
 load upon the glass 
 
 Air-pump. vegselj that a gtr0Dg 
 
 man could scarcely remove it from the plate, although it 
 
 Fig. 263. 
 
"WEIGHT OF THE ATMOSPHERE. 241 
 
 be no larger than a small tumbler. A glass jar with a 
 mouth six inches across would need a force equal to nearly 
 four hundred pounds to displace it. If Fig. 264. 
 
 there be a glass vessel open at both ends, 
 the hand placed on the top may be so 
 firmly held by the pressure that it can not 
 be removed until the air is again admit- 
 ted below (fig. 264). If a thin plate of 
 glass be placed on the top of this open T h e mZTfdcned 
 vessel, on pumping out the air, the ty4w. 
 
 weight will suddenly crush it with a noise like the report 
 of a gun. 
 
 Some interesting instances occur in nature of the use 
 of atmospheric pressure. Flies walk on glass by means 
 of the pressure against the outside of their feet, the air 
 having been forced out beneath. In a similar way, some 
 kinds of fishes cling to the sides of rocks under water, so 
 as not to be swept off by the current. Dr. Shaw threw a 
 fish of this kind into a pail of water, and it fixed itself so 
 firmly to the bottom, that, by taking hold of the tail, he 
 lifted up the pail, water and all. 
 
 It is the pressure of the atmosphere upon water that 
 drives it up the barrel of a pump as soon as the air is 
 pumped out from the inside. Hence the reason that 
 pumps can never be made to draw water more than thirty- 
 three feet below the piston, a height corresponding to the 
 weight of the atmosphere. In practice they never draw 
 water even to this height, as a perfect vacuum can not be 
 made by pumping. 
 
 THE BAROMETER. 
 
 On the same principle the Barometer is made. It con- 
 sists of a glass tube, nearly three feet long, open at one 
 end, and which is first filled with mercury, a liquid nearly 
 fourteen times heavier than water, The open end is then 
 11 
 
242 MACHINERY IN" CONNECTION WITH AIE. 
 
 placed downward in a cup of mercury. The weight of 
 the mercury in the tube causes it to descend until the 
 pressure of the atmosphere on the mercury in the cup 
 preserves an equilibrium, which takes place when the col- 
 umn in the tube has fallen to about two feet and a 
 half high, the upper part of the tube being left a 
 perfect vacuum, as no air can enter (fig. 265). N*ow, 
 as the height of the column of mercury depends 
 alone upon the weight of the atmosphere, then, 
 whenever the air becomes lighter or heavier, as it 
 constantly does during the changes of the weather, 
 the rising or falling of the column indicates these 
 changes ; and, what is very important, it shows 
 the approaching changes of the weather several 
 hours before they actually take place. Hence 
 it becomes a valuable assistant in foretelling 
 the weather. When the mercury falls, showing that 
 the atmosphere is becoming lighter, it indicates the 
 approach of storms or rain ; when it rises, a settled or fair 
 sky follows. These are often foreshown before there is 
 any change in the appearance of the sky. For this rea- 
 son the barometer is sometimes called a weather-glass. It 
 is of the greatest value to navigators at sea. Long 
 voyages, which formerly required a year, have been made 
 in eight months by means of the assistance afforded by 
 the barometer, admitting a full spread of canvas by night 
 as well as by day, from the certainty of its predictions. 
 On land its indications are not so certain, and at some 
 places less so than at others. Sometimes, and more com- 
 monly during autumn and winter, the sinking of the mer- 
 cury is followed only by wind instead of rain. There is, 
 however, no doubt that its use would be of much advant- 
 age in large farming establishments, more especially dur- 
 ing the precarious seasons of haying and harvesting. 
 
 The barometer is an instrument of great value in de- 
 termining with little labor, and with considerable accuracy, 
 
THE BAROMETER. 243 
 
 the heights of mountains, hills, and the leading points of 
 an extensive district of country. In rising above the level 
 of the sea, the weight of the air above us becomes less ; 
 that is, the pressure of the air upon the barometer de- 
 creases, and the column of mercury gradually falls as we 
 ascend. To determine, therefore, the height of a mount- 
 ain, we have only to place one barometer at its foot while 
 another stands at the top, and then, by observing the 
 difference in the height of the mercury, we are enabled to 
 calculate the height of the mountain. The following ta- 
 ble shows how much the barometer falls at different alti- 
 tudes, thirty inches being taken for the sea-level:* 
 
 At 1,000 feet above the sea, the column falls to 28.91 inches. 
 
 2,000 " " " " " 27.86 " 
 
 3^000 « " " " " 26.85 " 
 
 4,000 " " " " " 25.87 " 
 
 5^000 " " " " " 24.93 " 
 
 lmile " " " " 24.67 " 
 
 2 u u « « « 20.29 " 
 
 3 « " « " " 16.68 " 
 
 4 « « « " " 13.72 " 
 
 5 » " " " " 11.28 " 
 10 " " " " " 4-24 " 
 15 « " " " " 1.60 " 
 20 " " " " " 0.95 " 
 
 At the level of the sea, the barometer falls about one 
 hundredth of an inch for a rise of nine feet, or a little 
 more than the tenth of an inch for a rise of one hundred 
 feet. At a height of one mile it requires about eleven 
 feet rise to sink the mercury a hundredth of an inch. 
 
 In selecting land in mountainous districts of the coun- 
 try, where degrees of frost increase with increased alti- 
 tudes, and where the height of one portion above another 
 has an important relation to the cost of drawing loads up 
 
 * The mercury rarely stands as high as 30 inches at the level of the 
 sea, the mean height being about 29.5 inches. But this does not affect 
 the measurement of heights, which is determined, not by the actual 
 height, but by the difference in heights. 
 
244 
 
 MACHINERY IN CONNECTION WITH AIR. 
 
 and down hill, the barometer might become of much 
 practical value. 
 
 THE SYPHON. 
 
 The syphon operates on a principle quite similar to that 
 of the pump ; but, instead of pumping out the air of the 
 tube through which the water rises, a vacuum is created 
 Fig. 266. by the weight of a column of water, in 
 
 the following way : Fig. 26G represents a 
 syphon, which is nothing more than a 
 tube bent in the form of a letter U in- 
 verted. Now, if this be filled through- 
 out with water, and then placed with the 
 shorter arm in the vessel of water, A, 
 the weight of the column of water in the 
 longer arm, Avhich is outside, will over- 
 balance the weight of the other column, 
 and will therefore run out in a stream. This tends to cause 
 a vacuum in the tube, which is instantly filled by the water 
 rushing up the shorter arm, being driven up by the press- 
 ure of the atmosphere. A stream will consequently con- 
 tinue running through the syphon until the vessel is 
 drained. 
 
 The syphon may sometimes be very usefully employed in 
 emptying pools or 
 ponds of water on 
 high ground, with- 
 out the trouble of 
 cutting a ditch for 
 
 this purpose. For 
 instance, let a (fig. 267) represent a body of water which 
 it is desirable to drain off; by placing the lead tube, b c, 
 so that the arm, c, may be lowest, and apjuying a pump 
 at this arm to withdraw the air and fill the syphon with 
 water, it will commence running, and continue until the 
 
WINDS. 245 
 
 water has all been drawn off. Difficulties, however, some- 
 times occur. If the tube is small and very long, and the 
 descent is trifling, the friction of the water in the tube 
 may prevent success. "Water usually gives out small 
 quantities of air, which collects in the higher part of the 
 syphon, and after a while fills it, causing the stream to 
 cease running ; but syphons for this purpose, when only a 
 few rods in length, with several feet descent, are usually 
 found to succeed well. If the discharging orifice is sev- 
 eral times smaller than the tube, it is frequently of material 
 use, by causing a slow and steady current through the 
 syphon. 
 
 CHAPTER II. 
 
 MOTION OF AIR. 
 WINDS. 
 
 Wind is air in motion. Its force depends on its speed. 
 When its motion is slow, it constitutes the soft, gentle 
 breeze. As the velocity increases, the force becomes 
 greater, and the strong gale sweeps around the arms of 
 the wind-mill with the strength of many horses, and huge 
 ships are driven swiftly through the waves by its press- 
 ure. By a still greater velocity of the air, its power be- 
 comes more irresistible, and solid buildings totter, and 
 forest trees are torn up by the roots in the track of the 
 tornado. 
 
 The force of wind increases directly as the square of 
 the velocity. Thus a wind blowing ten miles an hour ex- 
 erts a pressure four times as great as at five miles an hour, 
 and twenty-five times as great as at two miles an hour. 
 
246 
 
 MACHINERY IN CONNECTION WITH AIR. 
 
 The following table exhibits the force of wind at different 
 degrees of velocity : 
 
 Description. 
 
 Hardly perceptible. 
 
 Just perceptible. 
 
 Miles an 
 hour. 
 
 1 
 
 2 
 
 3 
 
 4 
 
 5 
 
 6 
 
 7 
 10 
 15 
 20 
 25 
 30 
 35 
 40 
 45 
 50 
 60 
 80 
 100 
 
 Pressure in lbs. on 
 a square foot. 
 
 .005 
 .020 
 .045 
 .080 
 .125 
 .180 
 .320 
 .500 
 
 1 
 f 
 
 L80 ) 
 
 }2oy 
 
 .500 ) 
 1.125 \ 
 
 \ 
 \ 
 
 000 ) 
 125 f 
 
 2.000 
 
 3.125 
 
 4.500 
 
 6.125 
 
 8.000 
 
 LO 
 
 12.500 
 
 18.000 
 
 32.000 
 
 50.000 
 
 Light breeze. 
 Gentle, pleasant wind. 
 Pleasant, brisk wind. 
 Very brisk. 
 Strong, bigb wind. 
 
 Very high. 
 
 Storm or tempest. 
 Great storm. 
 Hurricane. 
 
 Tornado, teariug up trees, and sweeping off 
 buildings. 
 
 These forces may be observed at a time when the air is 
 still, by a forward motion equal to that of the wind. Thus 
 walking moderately gives the faint breeze against the 
 face ; riding in a wagon at six miles an hour causes the 
 sensation of a pleasant wind ; the deck of a steam-boat at 
 fifteen miles produces a brisk blow ; while an open rail-car 
 at forty miles an hour occasions a sweep of the air nearly 
 resembling a tempest. 
 
 The preceding table will enable any one to calculate 
 with considerable accuracy the amount of draught which 
 a horse must constantly overcome in traveling with a 
 covered carriage against the wind, adding, of course, the 
 speed of the horse to that of the wind. For example, 
 suppose a horse with a covered carriage is driven against 
 what we term " a very brisk wind," blowing 24 miles an 
 hour, and pressing 3 lbs. on the square foot. The carriage 
 top offers a resisting surface four feet square, or with six- 
 
MOTION AGAINST THE WIND. 247 
 
 teen square feet. Three times sixteen, or 48 lbs., are con- 
 sequently required to be overcome with every onward 
 step of the horse. Now, we have already seen, when 
 treating of " application of labor," that a horse traveling 
 three miles an hour for eight hours will overcome only 83 
 lbs. with ordinary working, which is not double the resist- 
 ance of the wind. Hence we perceive that more than 
 half the horse's strength is lost by driving against such a 
 current. At six miles an hour, all his strength, without 
 over-driving, would be expended in overcoming the force 
 of the wind, and the power required for moving the car- 
 riage would be so much excess of labor. For simplifying 
 the operation, the increased motion of the wind occasion- 
 ed by driving against it has not been taken into account. 
 Even with a small pressure, the loss in power is consid- 
 erable for an entire day. When, for example, the air is 
 perfectly still, traveling six miles an hour will cause a con- 
 stant resistance of 3 lbs. on the carriage, or one-fourteenth 
 of the power exerted for a full day's work. The same 
 speed against a " gentle wind " of six miles an hour, add- 
 ed, would increase the resistance fourfold, or equal to 12 
 lbs. ; more than one-fourth of the horse's strength at six 
 miles an hour through the day. 
 
 WIND-MILLS. 
 
 The power possessed by the sails of a wind-mill may be 
 nearly ascertained in the same way, the area of the sails 
 being known, and first deducting their average velocity. 
 
 In all wind-mills, it is important that the sails should 
 have the right degree of inclination to the direction of the 
 wind. If they were to remain motionless, the angle 
 would be different from that in practice. They should 
 more nearly face the wind ; and as the ends of the sails 
 sweep around through a greater distance and faster, they 
 should present a flatter surface than the parts nearer the 
 
248 
 
 MACHINERY IX CONNECTION WITH AIR. 
 
 centre. The sails should, therefore, have a twist, to give 
 them the most perfect form, so that the parts nearest the 
 centre may form an angle of about 68 degrees with the 
 wind, the middle about 72 degrees, and the tips about 83 
 degrees. 
 
 In order to produce the greatest effect, it is necessary to 
 give the sails a proper velocity as compared with the ve- 
 locity of the wind. If they were entirely unloaded, the ex- 
 tremities would move faster than the wind, in consequence 
 of its action on the other parts. The most useful effect is 
 ]3roduced when the ends move about as fast as the wind, 
 or about two-thirds the velocity of the average surface. 
 
 The most useful wind is one that moves at the rate of 
 eight to twenty miles per hour, or with an average press- 
 ure of about one pound on a square foot. In large wind- 
 mills, the sails must be lessened when the wind is stronger 
 
 than this, to prevent the 
 arms from being broken ; 
 and if much stronger, it 
 is unsafe to spread any, 
 or to run them. 
 
 The force of wind may 
 be usefully applied by al- 
 most every farmer, as it 
 is a universal agent, pos- 
 sessing in this respect 
 great advantages over 
 water-power, of which 
 very few farms enjoy 
 the privilege. 
 
 Wind may be applied 
 to various purposes, such 
 as sawing wood by the 
 aid of a circular saw, 
 turning grindstones, and particularly in pumping water. 
 One of the simplest contrivances for pumping is represented 
 
 Wind-mill for pumping water on farms , 
 A, wind-mill; B,vane; 1, pump-rod. 
 
WIND-MILL FOR TUMPING WATER. 
 
 249 
 
 by fig. 268, where A is the circular wind-mill, with a number 
 of sails set obliquely to the direction of the wind, and al- 
 ways kept facing it by means of the vane, B. The crank of 
 the wind-mill, during its revolutions, works the pump-rod, I, 
 and raises the water from the well beneath. In whatever di- 
 
 Flg; 2G0. 
 
 Barn surmounted with wind-mill for pumping water t 
 cutting straw, t{C. 
 
 rection the wind may blow, the pump will continue work- 
 ing. The pump-rod, to work steadily, must be immediately 
 under the iron rod on which the vane turns. If the di- 
 ameter of the wind-mill is four feet, it will set the pump 
 in motion even with a light breeze, and with a brisk wind 
 will perform the labor of a man. Such a machine will 
 pump the water needed by a herd of cattle, and it may be 
 placed on the top of a barn, with a covering, to Avhich may 
 be given the architectural effect of a tower or cupola, as 
 shown in fig. 269. 
 
 A more compact machine, but of more complex con- 
 struction, is shown in fig. 270, where the upper circle 
 moves around with the wheel and vane on the fixed lower 
 circle, to which it is strongly secured so as to admit of 
 turning freely. In other respects it is similar to the pre- 
 ceding. 
 
 11* 
 
250 MACHINERY IN CONNECTION WITH AIR. 
 
 Fte. 270. 
 
 Wind-mills, like the preceding, which have fixed sails, 
 should not be more than three or four feet in diameter ', 
 and even then will require care in storms. If larger, 
 they will become broken by severe winds. The remedy is 
 either to move the sails by hand at every considerable 
 change in the. force of the current, which would require 
 nearly constant attention ; or to use the self-regulating ma- 
 chines, of which there have been several invented, some 
 of which have proved useful and durable. 
 
 Halliday's wind-mill has been much used for several 
 years, and is made of various sizes, the larger possessing 
 the power of several horses. It is self-regulated, in the 
 following manner : When the mill begins to run too fast, 
 it pumps water rapidly into a chamber or cylinder, and 
 this increase of water moves an arm which turns the fans 
 
•BROWN S WIND-MILL. 
 
 251 
 
 edgewise to the wind. When the wind slackens, a re- 
 verse movement takes place. 
 
 Brown's wind-mill, made by the Empire Wind-mill Com- 
 pany, of Syracuse, is a more recent invention, and has 
 proved very successful. The annexed figure (fig. 271), rep- 
 rig. 271. 
 
 Brown's {or Empire) Wind-mill. 
 
 resents one of the smaller sizes, adapted to farm jmrposes 
 and pumping water for cattle. It is regulated in part by 
 the centrifugal force of weights, and partly by the direct 
 pressure of the wind. This regulating contrivance ren- 
 ders the mill safe, even in a gale of wind. The larger 
 
252 MACHINERY IN CONNECTION WITH AIR. 
 
 sizes, which are fifty feet or more in diameter, possess 
 much power, and are used for grinding grain, and other 
 purposes. 
 
 The work which a wind-mill is capable of doing de- 
 pends very much on the site. If placed where the wind 
 has a long, uniform, and steady sweep, it will accomplish 
 much more, and to better satisfaction, than if among hills 
 or other obstructions, where the blasts are uncertain and 
 changing. 
 
 Wind-mills of large size are peculiarly adapted to pump- 
 ing water into reservoirs, or from mines or quarries, w T here 
 a few days of calm weather will not result in inconven- 
 ience ; but they are not suited to manufactories where a 
 constant power is required to furnish employment to men, 
 but can be used for work w r hich may be intermitted or 
 changed. 
 
 Brown's wind-mill is sold at $75 dollars for the small 
 size, with increase of prices up to $1,200 for large ones. 
 
 CAUSES OF WIND. 
 
 The motion of air, in producing wind, is explained by 
 the action of heat, although there are many irregular cur- 
 rents whose cause is not well understood. The simplest 
 illustration of the effect of heat in causing currents is fur- 
 nished by the land and sea-breezes in warm latitudes. 
 The rays of the sun during the day heat the surface of 
 the land, and the air in contact with it, also becoming 
 heated, and thus rendered lighter, flows upward ; the air 
 from the sea rushes in to fill the vacancy, and causes the 
 sea-breeze. During the night, the radiation of heat from 
 the land into the clear sky above cools the surface to a 
 lower temperature than that of the sea ; consequently, 
 the air in contact with the sea becomes heated the most, 
 and rising, causes the wind from the land to flow in and 
 supply the place. Trade-winds are caused in a similar 
 
CHIMNEY CURRENTS. 253 
 
 way, but on a much larger scale, by the greater heat of 
 the earth at the equator, which produces currents from 
 colder latitudes. These currents assume a westerly tend- 
 ency, in consequence of the velocity of the earth being 
 the greatest at the equator, and which, outstripping the 
 momentum which the winds have acquired in other lati- 
 tudes, tends to throw them behind, or in a westerly di- 
 rection. 
 
 CHIMNEY CURRENTS. 
 
 Chimney Currents are produced by the heat of the fire 
 rarefying the air, which rises, and carries the smoke with 
 it. The taller the chimney is, the longer will be the 
 column of rarefied air tending upward ; and, as a conse- 
 quence, the stronger will be the draught. In kindling a 
 fire in a cold chimney, there is very little current till this 
 column becomes heated. The upward motion of heated 
 currents is governed by laws similar to the downward mo- 
 tion of water in tubes, where the velocity is increased 
 with the height of the head. But as air is more than 
 eight hundred times lighter than water, slight causes will 
 affect its currents, which would have no sensible influence 
 on the motion of liquids. For instance, a strong wind 
 striking the top of a chimney may send the smoke down- 
 ward into the room ; and a current can not be induced 
 through a horizontal pipe without connecting with it an 
 upright pipe of considerable height. 
 
 CONSTRUCTION OF CHIMNEYS. 
 
 In constructing chimneys to produce a strong draught, 
 the throat immediately above the fire, which should have 
 a breadth equal to that of the fireplace, should be con- 
 tracted to a width of about four inches, so that the column 
 
254 
 
 MACHINERY IN CONNECTION WITH AIR. 
 
 ''V, 
 
 of rising air above may draw the air up through the 
 Fig. 2T2. throat with increased velocity, as 
 
 shown in fig. 272. This arrange- Fi m 
 raent also allows the fire to be built 
 so as to throw the heat more fully 
 out into the room. By leaving the 
 shoulder at b square or flat, it will 
 tend to arrest any reversed or 
 downward current in a better man- 
 ner than if built sloping, as shown 
 by the dotted line at a, which 
 would act like a funnel, and throw 
 the smoke into the room. The 
 throat should be about as high as 
 the extreme tip of the flame ; if 
 much higher, the chimney will not 
 draw so well, and if lower, too 
 much of the heat will be lost. 
 Fig. 273 shows a fireplace without a contracted throat, 
 the current of which is comparatively feeble. Many 
 chimneys draw badly by being made too large for the fire 
 to heat sufficiently the column of air they contain. 
 
 A well-built 
 Chimney. 
 
 A badly-built 
 Chimney. 
 
 CHIMNEY-CAPS. 
 
 When wind sweeps over the roof of a high part of the 
 building, or over a hill, it often strikes the Fig. 274. 
 tops of chimneys below, and drives the smoke 
 downward. This may be often prevented 
 by placing a cap over the chimney, like that 
 represented by fig. 274, which is supported at 
 its corners, the smoke passing out at the four 
 sides just under the eaves of this cap. But 
 it sometimes happens that there is a confusion of currents 
 and eddies at the top of the chimney, over which this cap 
 
CHIMNEY-CAPS. 
 
 255 
 
 Fisr. 275. 
 
 has no influence. In this case, the cap represented by fig. 
 275 furnishes a complete remedy, and is, in- 
 deed, perfect in its operation under any cir- 
 cumstances whatever, for the chimney sur- 
 mounted by it will always draw when there 
 is wind from any quarter, with or without a 
 fire. It has effected a perfect cure in some 
 chimneys which before were exceedingly 
 troublesome, and were regarded as incurable. Fig. 276 is 
 intended to show the mode of its Fig. 276. 
 
 operation ; the wind, as shown by 
 the arrows, being deflected for a 
 considerable distance on the lee 
 side, so as to form a vacancy at a, 
 which the wind from the other end 
 and from the chimney both rush in to supply. Being 
 fixed on without turning in the chimney, it is both simpler 
 and less noisy than any caps furnished with a vane. 
 
 Emersorfs Chimney-cap is different in construction, 
 Fig. 277. but quite simi- Fig. 278. 
 
 lar in principle 
 to the preced- 
 ing. It is shown 
 bf fig. 277. A 
 sheet-iron pipe 
 is set in the top 
 of the chimney, 
 furnished with 
 the conical rim, and a plate 
 or fender on the top, which ex- 
 cludes the rain. Between the 
 plate and rim is a space quite 
 similar in form or section to 
 that represented by fig. 276. 
 In exposed situations, chim- 
 neys are found to draw more uniformly by contracting 
 
256 
 
 MACHINERY IN CONNECTION WITH ATE. 
 
 the top about a third less than the rest of the flue. The 
 Fig. 279. current at the moment of escape is swifter 
 than below, and less acted upon by any down- 
 ward blast of the wind, at the same time 
 that the surface is smaller on which the wind 
 can strike the current, as shown in fig. 278. 
 A chimney of this character may be very 
 easily made by contracting the tiers of brick, 
 thus giving to it an ornamental appearance, 
 as seen in fig. 279.* 
 
 * Where different fires communicate with the same chimney, separate 
 flues should be built for each fire, ana kept separate in the same chim- 
 ney-stack, carried up independently of each other. But even with this 
 precaution, smoky rooms will not be avoided, unless the termination of 
 the chimney is of the right form, of which the following illustration is 
 given in Allen's Rural Architecture : 
 
 "Fifteen years ago we purchased and removed into a most substantial 
 and well-built stone house, the chimneys of which were constructed 
 with open fireplaces, and the flues carried up separately to the top, 
 where they all met upon the some level surface, as chimneys in past times 
 usually were built thus (fig. 2S0). Every fireplace in the house (and some 
 of them had stoves in) smoked intolerably; so much so, that when the 
 wind was in some quarters, the fires had to be put out in every room 
 but the kitchen, which, as good luck would have it, 6moked less — al- 
 though it did smoke there — than the others. After balancing the mat- 
 ter in our own mind some time whether we would pull down and re- 
 build the chimneys altogether, or attempt an alteration — as we had 
 
 Fig. 281. 
 
 Tis. 2so. 
 
 given but little thought to the sub- 
 ject of chimney draught, and to try 
 an experiment was the cheapest — 
 we set to work a bricklayer, who, 
 under our direction, simply built 
 over each discharge of the several 
 flues a separate top of fifteen inches 
 high, in this wise : Fig. 281. The / 
 remedy was perfect. We have had no smoke in the house since, blow 
 the wind as it may, on any and on all occasions. The chimneys can't 
 smoke ; and the whole expense for four chimneys, with their twelve 
 flues, was not twenty dollars ! The remedy was in giving each outlet a 
 distinct current of air all around, and ou every side of it." 
 
VENTILATION OF ROOMS. 
 
 257 
 
 Fie:. 282. 
 
 VENTILATION. 
 
 Impure air may be breathed for a short time without 
 any serious detriment, but to live in it and respire it for 
 years can not fail to produce permanent injury to the 
 health. During the heat of summer, open doors and win- 
 dows will usually furnish plenty of fresh air, so long as 
 this season lasts, which in the Northern States is not one 
 half the year. During the rest of the time, rooms are 
 heated with close stoves, and unless special care is taken 
 to secure fresh air, pale or sickly inmates wilt be the most 
 
 likely results. 
 
 Even with a common open fireplace, which causes more 
 circulation of the air in a room than stoves, the ventila- 
 tion is very imperfect. The following figure (fig. 282) 
 
 represents the fresh air 
 as passing in from an 
 open window opposite 
 the fire, producing a 
 direct current from the 
 window to the chim- 
 ney, and leaving all the 
 upper portion of the 
 room filled with bad 
 air, unaffected by the 
 chancre. The cold air 
 can not rise, nor the 
 a badhj-vudiiaud Room. -j^t air descend. This 
 
 difficulty may be easily removed by placing a register 
 (which may be closed or opened at pleasure) at a, in the 
 upper corner, so that the confined air may escape into the 
 chimney. Without this provision, it is nearly impossible 
 to preserve the air in proper condition for breathing, for 
 the upper part, being warmest and lightest, remains un- 
 changed at the top. In rooms heated by stoves, registers 
 for the escape of the foul air are still more important, where 
 
258 
 
 MACHINERY IX CONNECTION "WITH AIK. 
 
 the thermometer frequently indicates twenty degrees dif- 
 ference in the heat above and at the floor, the lower 
 stratum of air resting like a cold lake about the feet, 
 while the head is heated unduly. 
 
 When the draught of the chimney-fire is not strong, 
 the smoke may, however, escape through the ventilating 
 register into the room. To avoid this difficulty, it is best 
 to provide separate air-flues in the walls when the house 
 is built, for effecting perfect ventilation. In rooms strong- 
 ly heated by fires, the fresh air should be admitted near 
 
 the ceiling, producing descending 
 
 currents, and effecting a complete 
 
 circulation in the air of the room. 
 
 But in sleeping apartments, and in 
 
 closets, not heated artificially, and 
 
 where the descending currents will 
 
 not take place, the fresh air should 
 
 Mode of ventilating Garrets. \)Q admitted through a register or 
 
 small rolling blind near the floor, and discharged near the 
 
 ceiling into an air-flue. 
 
 The excessive warmth of garrets in midsummer may 
 
 Fisr. 283. 
 
 Fig. 2S5. 
 
 Fig. 284. 
 
 Mode of Ventilating half-story Bod- 
 rooms. 
 
 Griffith's Ventilator. 
 
 be avoided by placing a ventilator at the highest part, 
 
Griffith's patent ventilator. 259 
 
 and admitting air at windows or openings near the eaves 
 (fig. 283), thus sweeping all the hot air out by the cur- 
 rent produced ; or the oppressive heat of half-story bed- 
 rooms may be similarly avoided, by creating a current of 
 air between the roof and the plastering (fig. 284). Two 
 modes may be adopted, as represented on each side of the 
 figure. 
 
 Fig. 285 represents Griffith's patent ventilator, for chim- 
 neys, and for giving a current of air through apartments. 
 It is made of iron, working as a screw fan, the slightest 
 wind causing it to revolve and establish a current through 
 the pipe which it surmounts. 
 
PART IV. 
 
 HEAT. 
 
 CHAPTER I. 
 
 CONDUCTING POWER OF BODIES. 
 
 When any substance or body has become heated, it 
 loses its heat in two different ways, by conduction and by 
 radiation. When conducted, heat passes off slowly or 
 gradually through bodies, as when a pin is held by the 
 hand in a candle, the heat advances from, one end to the 
 other till it burns the fingers ; or, when an iron poker is 
 thrust into the fire, the heat gradually passes through it 
 till the whole becomes hot. Iron and brass are, there- 
 fore, said to be good conductors of heat. The end of a 
 pipe-stem may, however, be heated to redness, and a 
 wooden rod may be set on fire without even warming the 
 other extremity, because the heat is very slowly conducted 
 through them. Wood and burned clay are, therefore, 
 poor conductors. 
 
 The comparative conducting power of different sub- 
 stances may be shown by placing short rods of each with 
 one of their ends in a vessel of hot sand, the others to be 
 tipped with wax. The different periods of time required 
 to melt the wax indicate the relative conducting powers. 
 It will speedily melt on the copper rod ; soon after, on 
 the rod of iron ; glass will require longer time ; stone or 
 earthenware, still longer; while on a rod of wood, it 
 will scarcely melt at all. These rods should be laid hori- 
 zontally, that the hot air rising from the sand may not 
 260 
 
UTILITY OF THE CONDUCTING POWER OP BODIES. 261 
 
 affect the wax. The conducting powers may be judged 
 of, likewise, with considerable accuracy in cold w r eather, 
 by merely placing the hand upon the different substances. 
 The best conductors will feel coldest, because they with- 
 draw the heat most rapidly from the hand. Iron will feel 
 colder than stone ; stone colder than brick ; wood, still 
 less so ; and feathers and down, least of all, although the 
 real temperature of all may be precisely the same. 
 
 UTILITY OF THIS PRINCIPLE. 
 
 A knowledge of this property is often very useful. For 
 instance, it is found that hard and compact kinds of wood, 
 as beach, maple, and ebony, conduct heat nearly twice as 
 rapidly as light and porous sorts, like pine and bass-wood. 
 Hence, doors and partitions made of light wood make a 
 warmer house than those that are more heavy and com- 
 pact. Pine or bass-wood would, in this respect, be better 
 than oak or ash. 
 
 Porous substances of all kinds are the poorest conduct- 
 ors ; sawdust, for example, being much less so than the 
 wood that produced it. For this reason, sawdust has 
 been used as a coating around the boilers of locomotives, 
 to keep in the heat, and for the walls of ice-houses, to ex- 
 clude it. Sand, filled in between the double walls of a 
 dwelling, renders it much warmer in winter, and cooler 
 in summer, than if sandstone were made to fill the same 
 space. Ashes, being more porous, are found to be still 
 better. Tan, which is similar to sawdust, is well adapted 
 to filling in the walls of stables and poultry -houses, where 
 more than usual warmth in winter is required. Confined 
 air is a very poor conductor of heat ; hence the advantage 
 of double walls and double windows, provided there are 
 no crevices for the escape of the confined air. This prin- 
 ciple has been lately applied in the manufacture of hollow 
 brick for building the walls of dwellings. 
 
2G2 
 
 HEAT. 
 
 The light and porous nature of snow renders it eminent- 
 ly serviceable as a clothing to the earth in the depth of 
 winter, preventing the escape of the heat from below, and 
 protecting the roots of plants from injury or destruction. 
 Hence the very severity of the cold of the Northern re- 
 gions, by producing an abundance of those beautiful 
 feathery crystals which form snow, becomes the means of 
 protecting from its own effects the tender herbage buried 
 beneath this ample shelter. 
 
 CONDUCTING POWER OF LIQUIDS. 
 
 Fi?. 28fi 
 
 Liquids are found to conduct heat very slowly, and 
 they were for a long time considered perfect non-conduct- 
 ors. Some interesting experiments have been performed 
 in illustration of this property. A large glass jar may be 
 filled with water (fig. 286), in which may be fixed an 
 air thermometer, which is always quickly sensitive to 
 small quantities of heat. A shallow cup of ether, floating 
 
 just above the bulb, may be set on 
 fire, and will continue to burn for 
 some time before any effect can be 
 seen upon the thermometer. The 
 upper surface of a vessel of water 
 has been made to boil a Ions: time 
 with a piece of unmelted ice at the 
 bottom. Liquids are found, how- 
 ever, to possess a conducting power 
 in a very slight degree. 
 
 When a vessel of water is heated 
 in the ordinary way over a fire, 
 the heat is carried through it merely by the motion 
 of its particles. The lower portion becomes warm, 
 and expands; it immediately rises to the surface, and 
 colder portions sink down and take its place, to ascend in 
 their turn. In this way, a constant circulation is kept up 
 
EXPANSION BY HEAT. 
 
 26; 
 
 among the particles. These rising and descending cur- 
 rents °are shown by the arrows in fig. 287. This result 
 may be easily shown by filling a flask with water into 
 which a quantity of sawdust from some green hard wood 
 has been thrown, which is about as heavy as water. It 
 will traverse the vessel in a manner precisely as shown 
 in the figure. 
 
 These results indicate the importance of applying heat 
 directly to the bottom of all vessels in which water is in- 
 tended to be heated. A considerable loss of heat often 
 occurs when the flame is made to strike against the sides 
 only of badly arranged boilers. 
 
 EXPANSION BY HEAT. 
 
 An important effect of heat is the expansion of bodies. 
 Among many ways to show it, an iron rod may be so fit- 
 ted that it will just enter a hole made for the purpose in 
 a piece of sheet-iron. If the rod be now heated in the 
 fire, it expands and becomes larger, and can not be thrust 
 
 Fipr. 288. 
 
 into the hole. The expansion may be more visibly shown 
 and accurately measured by means of an instrument called 
 the Pyrometer (fig. 288). The rod a b, secured to its 
 
264 HEAT. 
 
 ])lace by a screw at «, presses against the lever c, and this 
 against the lever or index d, both of which multiply the 
 motion, and render the expansion very obvious to the eye 
 when the rod is heated by the lamps. If the rod should 
 expand one-fiftieth of an inch, and each lever multiplies 
 twenty times, then the index (or second lever) will move 
 along the scale eight inches ; for 20 times 20 are 400, and 
 400-50ths of an inch are 8 inches. 
 
 Many cases showing the expansion of heated bodies oc- 
 cur in ordinary practice. One is afforded by the manner 
 in which the parts of carriage wheels are bound together. 
 The tire is made a little smaller than the wooden part of 
 the wheel; it is then heated till, by exjmnding, it be- 
 comes large enough to be put on, when it is suddenly 
 cooled with water, and, by its powerful contraction, binds 
 every part of the wheel together with great force. Hogs- 
 heads are firmly hooped with iron bands in the same way, 
 with more force than could ever be given by driving 
 with blows of the mallet. 
 
 This principle was very ingeniously applied in drawing 
 together two expanding brick walls of a large building in 
 Paris, which threatened to burst and fall. Holes were 
 drilled in the opposite walls, through which strong iron 
 bars across the building projected, and circular plates of 
 iron were screwed on these projecting ends. The bars 
 were then heated, which increased their length ; the plates 
 were next screwed closely against the walls. On cooling, 
 they contracted, and drew the walls nearer together. The 
 process was repeated on alternating bars, until the walls 
 were restored to their perpendicular positions. 
 
 All tools, where the wooden handles enter iron sockets, 
 will hold more firmly if the metal is heated before insert- 
 ing the wood. 
 
 The metallic parts of pumps sometimes become very 
 difficult to unscrew, and a case has occurred where two 
 strong men could not start the screws, until a bystander 
 
EFFECTS OF SUDDEN EXPANSION. 
 
 265 
 
 suggested that the outer piece "be heated, keeping the in- 
 ner cool, when a force of less than ten pounds quickly 
 separated them. In other cases, where the large iron nuts 
 have been thoughtlessly screwed, while warmed with the 
 hands, on the cold metallic axles of wood-sawing ma- 
 chines in winter, they have contracted so that the force 
 of two or three men has been insufficient to turn them. 
 
 The sudden expansion of bodies by heat sometimes 
 causes accidents. Thick glass vessels, when unequally 
 heated, expand unequally, and break. Heated plates of 
 cast-iron or cast kettles are liable to be fractured by 
 suddenly pouring cold water upon them. The same ef- 
 fect has been usefully applied in splitting the scattered 
 rocks which encumber a farm, and which are too large to 
 remove while entire. Fires are built upon them ; the up- 
 per surface expands while the lower remains cold, and 
 large portions are successively separated in scales, and 
 sometimes the whole rock is severed. The only care 
 needed is to observe attentively and remove with an iron 
 bar any parts which may have become loosened by the 
 heat, and which would prevent the heat from passing to 
 other portions. One man will thus attend to a large 
 number of fires, and will split in pieces ten times as many 
 rocks in a day as by drilling and blasting. 
 
 Fijr. 389. 
 
 THE STEAM-ENGINE. 
 
 The Steam-engine owes its power to 
 the enormous expansion of water at the 
 moment it is converted into steam, which 
 is about 1,600 times its bulk when in 
 a liquid state. The principle on which 
 the steam-engine acts may be understood 
 by a simple instrument, represented 
 in fi>. 289. A fflass tube with a small 
 bulb is furnished with a solid, air- 
 tight piston, capable of working up and 
 12 
 
266 HEAT. 
 
 down. The water in the bulb, «, is heated with a 
 spirit-lamp or sand-bath ; the rising steam forces up the 
 piston. Now, immerse the bulb in cold water or snow, 
 and the steam is condensed again into water, the tube is 
 left vacant, and the pressure of the atmosphere forces 
 down the piston. By thus alternately applying heat and 
 cold, it is driven up and down like the piston of a steam- 
 engine. The only difference is, the steam-engine is fur- 
 nished with apparatus so that this application of heat and 
 cold is performed by the machine itself. The bulb repre- 
 sents the boiler, and the tube the cylinder ; but in the 
 steam-engine, the boiler is separate, and connected by a 
 pipe with the cylinder ; and instead of applying the cold 
 water directly to the cylinder, it is thrown into another 
 vessel, called the condenser, connected with the cylinder. 
 
 When IsTewcomen, who made the first rude regularly 
 working engine, began to use it for pumping water, he 
 employed a boy to turn a stop-cock connected with the 
 condenser, every time the piston made a stroke. The 
 boy, however, soon grew tired of this incessant labor, and 
 endeavored to find some contrivance for relief. This he 
 effected by attaching a rod from the piston or working- 
 beam to the cock, which was turned by the machine itself 
 at every stroke. This was the origin of the first self- 
 acting engine. 
 
 The different parts ot a common steam-engine may be 
 understood from the following figures, one representing 
 the boiler, and the other the working machinery. 
 
 The boiler, JB (fig. 290), contains water in the lower 
 part, and steam in the upper ; F JB is the fire ; v o is the 
 feed-pipe y v, a valve, closed by the lever b c a, whenever 
 the boiler is full enough, by means of the rising of the 
 float, S, and opened whenever the float sinks from low 
 water. _3f, barometer gauge, to show the pressure of the 
 steam ; w, weight on the lever, e b, for holding down the 
 safety-valve : this lever being graduated like a steelyard, 
 
THE STEAM ENGINE. 
 
 267 
 
 the force of the steam may be accurately weighed. £7" is 
 a valve opening downward, to prevent the boiler being 
 crushed by atmospheric pressure, by allowing the air to 
 pass in whenever the steam happens to decline. Two 
 
 Fig. 290. 
 
 Boiler of Steam-engine. 
 
 tubes, with stop-cocks, c and. d, one just below the water- 
 level, and the other just above it, serve to show, by open- 
 ing the cocks, whether the water is too high or too low. 
 
 The working part of the engine is represented in the 
 figure on the following page (fig. 291). The steam enters 
 by the pipe, s, from the boiler on the other side of the 
 brick wall, as shown in fig. 290. The steam passes through 
 what is called a four-way-cock, a, first into the lower, then 
 into the upper end of the cylinder, C, as the piston, P, 
 moves up and down ; this is regulated by the levers, y y. 
 The piston-rod, E, is attached to the working-beam, JB 
 F, turning on the centre, A. The rod, F 7?, turns the fly- 
 wheel, H H, and drives the mill, steam-boat, or machinery 
 to be set in motion. 
 
268 
 
 HEAT. 
 
 The condenser,^', shown directly under the cylinder, re- 
 mains to be described. It is immersed in a cistern of cold 
 water, and is connected by pipes with the upper and lower 
 end of the cylinder. Through these pipes the steam 
 
 Through 
 
 Fi.2\ 291. 
 
 Low-pressure Steam-engine, 
 
 passes out of the cylinder, first from one end and then 
 from the other, and is condensed into water by a jet of 
 cold water thrown into it by the injection-cock. When 
 condensed, it is pumped out by the pump, 0, into the well 
 or reservoir, W, and then again into the feed-pipe of the 
 boiler. Warm water is thus constantly supplied to the 
 boiler, and effects a great saving of fuel. 
 
 The supply of steam and the motion of the engine are 
 regulated by the governor, G. When the motion is too 
 fast, the two suspended balls, which revolve on a vertical 
 or upright axis, and which hang loosely like pendulums, 
 are thrown out from the axis, producing the movement of 
 a rod which shuts the steam-valve. When the motion 
 
QUALITIES OF THE STEAM-ENGINE. 269 
 
 is too slow, the balls approach the axis, and open the 
 valve. 
 
 In high-pressure engines, the steam is not condensed, 
 but escapes into the open air at every stroke of the piston, 
 which produces the loud, successive puffs of all engines 
 of this kind. 
 
 The steam-engine, in its most perfect form, is a striking 
 example of human ingenuity, and its qualities are thus 
 described by Dr. Arnott : "It regulates with perfect ac- 
 curacy and uniformity the number of its strokes in a given 
 time, arid records them as a clock does the beats of its 
 pendulum. It regulates the quantity of steam ; the brisk- 
 ness of the fire ; the supply of water to the boiler ; the 
 supply of coals to the fire. It opens and shuts its valves 
 with absolute precision as to time and manner ; it oils its 
 joints; it takes out any air accidentally entering parts 
 which should be vacuous; and when any thing goes 
 wrong which it can not of itself rectify, it warns its at- 
 tendants by ringing a bell ; yet, with all these qualities, 
 and even when exerting a force of six hundred horses, it 
 is obedient to the hand of a child. Its aliment is coal, 
 wood, and other combustibles. It consumes none while 
 idle. It never tires, and wants no sleep. It is not sub- 
 ject to any malady when originally well made, and only 
 refuses to work when worn out with age. It is equally 
 active in all climates, and will do work of any kind ; it is 
 a water-pumper, a miner, a sailor, a cotton-spinner, a 
 weaver, a blacksmith, a miller, a printer, and is indeed of 
 all occupations ; and a small engine in the character of a 
 steam pony may be seen dragging after it, on an iron rail- 
 way, a hundred tons of merchandise, or a thousand per- 
 sons with the speed of the wind." 
 
 Steam-engines have been much used on large farms in 
 England for thrashing, grinding the feed of animals, cut- 
 ting fodder, and for other purposes. A successful English 
 farmer has used a six-horse steam-engine to drive a pair 
 
270 
 
 HEAT. 
 
 of mill-stones, for thrashing and cleaning grain, elevating 
 
 and bagging it, pumping water for cattle, cutting straw, 
 
 Fig. 292. turning a grindstone, 
 
 and driving liquid ma- 
 nure through pipes 
 for irrigating his fields, 
 employing the waste 
 steam in cooking 
 food for cattle and 
 swine. In this country, 
 where horse labor is 
 cheaper, steam-engines 
 have not come into so 
 general use; but on 
 large farms, where a 
 Wood's Farm Engine. ten - horse - power or 
 
 more is required, they have been employed to much 
 advantage, consuming no food, and requiring no care 
 
 Fie. 203. 
 
 Wood's Engine on WJieels, with Pipe Folded Down. 
 when idle. Excellent steam-engines for this purpose 
 are manufactured by A. N. Wood & Co., of Eaton, 
 
wood's steam-engine. 271 
 
 Madison Co., N. Y., a representation of which is given 
 in the accompanying figure (fig. 292.) When intended to 
 move from place to place, these engines are furnished ready 
 mounted on wheels (fig. 293). The twelve-horse-power 
 engines cost about $1,000, and have thrashed over a hund- 
 red bushels per hour, using half a cord of wood, or 300 
 or 400 lbs. of coal for ten hours. A Western farmer 
 thrashed 14,250 bushels of wheat in five consecutive weeks, 
 working five and a half days each, with one of these en- 
 gines. The smoke-pipe is guarded, so that straw placed 
 within a few inches cannot be set on fire. 
 
 More difficulty obviously exists in adajDting the steam- 
 engine to plowing than for stationary purposes. In order 
 to possess sufficient power, when used as a locomotive, 
 the engine must be made so heavy as to sink in common 
 soft soil even with large and broad wheels ; and this 
 tendency is increased by the jar of the machinery which 
 these wheels support. For this reason, all locomotive 
 plows have failed. Better success has attended the use 
 of stationary engines, employed for drawing gangs of 
 plows, by means of wire rope, across the fields. In Eng- 
 land, wiiere much of the soil is tenacious, and where fuel 
 and manual labor are cheap, and horse labor expensive, 
 this mode of plowing has been found profitable when em- 
 ployed on an extensive scale, and is now much used. 
 
 EXCEPTION TO EXPANSION BY HEAT. 
 
 A striking exception to the general law of expansion by 
 heat occurs in the freezing of water.* During its change 
 to a solid state, it increases in bulk about one-twelfth, and 
 this expansion is accompanied with great force. The 
 bottoms of barrels are burst out, and cast-iron kettles are 
 split asunder, when water is suffered wholly to freeze in 
 
 * There are a very few other substances which expand on passing 
 from a liquid to a solid state. 
 
272 HEAT. 
 
 them. Lead pipes filled with ice expand ; but if it is 
 often repeated, they are cracked into fissures. A strong 
 brass globe, the cavity of which was only one inch in di- 
 ameter, was used by the Florentine academicians for the 
 purpose of trying the expansive force of freezing water, 
 by which it was burst, although the force required was 
 calculated to be equal to fourteen tons. Experiments 
 were tried at Quebec, in one of which an iron plug, nearly 
 three pounds in weight, was thrown from a bomb-shell to 
 the distance of 415 feet ; and in another, the shell was 
 burst by the freezing of the water which it contained. 
 
 This expansion has a most important influence in the 
 pulverization of soils. The water which exists through 
 all their minute portions, by conversion to frost, crowds 
 the particles asunder, and when thawing takes place, the 
 whole mass is more completely mellowed than could pos- 
 sibly be effected by the most perfect instrument. This 
 mellowing is, however, of only short duration, if the ground 
 has not been well drained to prevent its becoming again 
 packed hard by soaking with water. 
 
 But this is not the most important result from the ex- 
 pansion of water. Much of the existing order of nature 
 and of civilized life depends upon this property ; without 
 it the great mass of our lakes and rivers would become 
 converted into solid ice ; for, as soon as the surface became 
 covered, it would sink to the bottom, beyond the reach of 
 the summer's sun, and successive portions being thus add- 
 ed, the great body of all large rivers and lakes would 
 become permanently frozen. But instead of this disas- 
 trous consequence, the ice, by resting upon the surface, 
 forms an effectual screen from the cold winds to the wa- 
 ter below. 
 
 LATENT HEAT. 
 
 If a vessel of snow, which has been cooled down to 
 several degrees below freezing by exposure to the severe 
 
LATENT HEAT. 273 
 
 cold of winter, be placed over a steady fire with a ther- 
 mometer in the snow, the mercury will rise by the increas- 
 ing heat of the snow until it reaches the freezing point. 
 At this moment it will stop rising, and the snow will be- 
 gin to melt ; and although the heat is all the time passing 
 rapidly into the snow, the thermometer will remain per- 
 fectly stationary until it is all converted to water. The 
 heat that goes to melt the snow does not make it any hot- 
 ter ; in other words, it becomes latent (the Latin word for 
 hidden), so as neither to affect the sensation of the hand 
 nor to raise the thermometer. Now it has been found that 
 the time required to melt the snow is sufficient to heat the 
 same quantity of water, placed over the same fire, up to 
 172 degrees, or 140 degrees above freezing ; that is, 140 
 degrees have become latent, or hidden, in melting the 
 snow. 
 
 This same amount of heat may be given out again by 
 placing the vessel of water out of doors to freeze. A 
 thermometer will show that the water is growing colder 
 by the escape of the heat, until freezing commences. Af- 
 ter this it still continues to pass off, but the water becomes 
 no colder until all is frozen, as it was only the latent heat 
 of the water that was escaping. 
 
 A simple and familiar experiment exhibits the same 
 principle. Place a frozen apple, which thaw T s a little be- 
 low freezing, in a vessel of ice-cold water. The latent 
 heat of the water immediately passes into the apple and 
 thaws it, and in an hour or two it will be found like a 
 fresh apple and entirely free from frost ; but the latent 
 heat having escaped from the water next the apple, a thick 
 crust of ice is found to encase it. 
 
 The amount of latent heat may be shown in still an- 
 other way. Mix a pound of snow at 32 degrees, or at 
 freezing, with a pound of water at 172 degrees. All will 
 be melted, but the two pounds of water thus formed will 
 12* 
 
274 HEAT. 
 
 be as cold as the snow, showing that for melting it the 
 140 degrees in the hot water were all made latent. 
 
 ADVANTAGES OF LATENT HEAT. 
 
 If no heat became latent by the conversion of ice and 
 snow to water, no time would, of course, be required for 
 the process, and thawing would be instantaneous. On 
 the approach of warm weather, or at the very moment 
 that the temperature of the air rose above freezing, snow 
 and ice would all dissolve to water, and terrific floods and 
 inundations would be the immediate consequence. 
 
 LATENT HEAT OF STEAM. 
 
 A still larger amount of latent heat is required for the 
 conversion of water into steam ; for, again place the ves- 
 sel of water with its thermometer on the fire, it will rise, 
 as the heat of the water increases, to 212 degrees, and 
 then commence boiling. During all this time it will now 
 remain stationary at 212, until the water is all boiled away. 
 This is found to require nearly five times the period need- 
 ed to heat from freezing to boiling ; that is, nearly one 
 thousand degrees of heat are made latent by the conver- 
 sion of water into steam. 
 
 When the steam is condensed again to water, this heat 
 is given out. Hence the use made of steam conveyed in 
 pipes for heating buildings, and for boiling large vats or 
 tubs of water, by setting free this large amount of latent 
 heat which the fire has imparted to it. 
 
 GREEN AND DRY WOOD FOR FUEL. 
 
 A great loss is often sustained in burning green wood 
 for fuel, from an ignorance of the vast amount of latent 
 heat consumed to drive off the water the wood contains. 
 When perfectly green, it loses about one-third of its weight 
 
GREEN AND DRY WOOD FOR FUEL. 275 
 
 by thorough seasoning, which is equal to about 25 cubic 
 feet in every compact cord, or 156 imperial gallons. Now 
 all this water must be evaporated before the wood is burn- 
 ed. The heat thus made latent and lost, being five times 
 as great as to heat the water to boiling, is equal to enough 
 for boiling 780 imperial gallons in burning up every cord 
 of green wood. The farmer, therefore, who burns 25 
 green cords in a winter, loses heat enough to boil more 
 than fifteen thousand gallons of water, which would be 
 saved if his wood had been previously well seasoned un- 
 der shelter. 
 
 The loss in using green fuel is, however, sometimes 
 overrated. It has been found by experiment that one 
 pound of the best seasoned wood is sufficient to heat 27 
 lbs. of water from the freezing to the boiling point.* 
 This will be equal to heating and evaporating four pounds 
 of water by every pound of wood. The 25 cubic feet of 
 water, therefore, in every cord of green wood, weighing 
 about 1,500 pounds, would require nearly 400 pounds of 
 wood for its evaporation, or about one-seventh or one- 
 eighth of a cord. Hence we may infer that seven cords 
 of dry wood are about equal to eight cords of green. 
 This imperfect estimate will apply only to the best hard 
 wood, and will vary exceedingly with the different sorts 
 of fuel ; the more porous the wood becomes, the greater 
 will be the necessity for thorough seasoning. 
 
 * The following results show the heating power of several combust- 
 ibles : 
 1 lb. of wood (seasoned, but still holding 20 per cent of water) 
 
 raised from 32° to 212° 27 lbs. water. 
 
 lib. ofalcohol 68 " 
 
 1 lb. of charcoal 78 " 
 
 1 lb. of oil or wax 90 " 
 
 1 lb. of hydrogen 216 " 
 
 It should be remembered that by ordinary modes of heating water, a 
 very large proportion of the heat is wasted by passiDg up the chimney 
 and into surrounding bodies, and the air. 
 
276 HEAT. 
 
 Superficial observation often leads to very erroneous 
 conclusions. Seasoned wood will sometimes burn with 
 great rapidity, and, producing an intense heat for a short 
 time, will favor an overestimate of its superiority. Green 
 wood, on the other hand, kindles with difficulty, and 
 burns slowly and for a long time; hence, where the 
 draught of the chimney can not be controlled, it may be the 
 most economical, because a less proportion of heat may 
 be swept upward than by the more violent draught pro- 
 duced from dry materials. Where the draught can be 
 perfectly regulated, however, seasoned wood should be 
 always used, for convenience and comfort, and for economy. 
 
 Where wood is to be drawn to a distance, the preceding 
 estimate shows that the conveyance of more than half a 
 ton of water is avoided in every cord by seasoning. 
 
 CHAPTER II. 
 
 RADIATION OF HEAT. 
 
 The passage of heat through conducting bodies has 
 been already explained. There is another way in which it 
 is transmitted, termed radiation, in which it is thrown off 
 instantaneously in straight lines from hot bodies, in the 
 same way that light is thrown off from a candle. A 
 familiar instance is furnished by the common or open fire- 
 place, before which the face may be roasted with the 
 radiated heat, while the back is chilled with cold. A 
 screen held in the hand will intercept this radiated heat, 
 showing that it flies in right lines like the rays of light. 
 
 Radiated heat is reflected by a polished metallic surface, 
 
RADIATION OF HEAT. 277 
 
 in the same way that light is reflected by a looking-glass. 
 A plate of bright tin held near the fire will not for a long 
 time become hot, the heat being reflected from it without 
 entering and heating it. But if it be blackened with 
 smoke, it will no longer reflect, but absorb the heat, and 
 consequently will speedily become hot. This experiment 
 may be easily tried by placing a new tin cup containing 
 water over a charcoal fire, which yields no smoke. The 
 heat will be reflected into the fire by the tin, and the wa- 
 ter will scarcely become warm. But if a few pine shav- 
 ings be thrown on this fire, to smoke the surface of the tin, 
 it will then absorb the heat rapidly, and soon begin to 
 boil. This explains the reason that bread bakes more 
 slowly in a new tin dish, and that a polished andiron be- 
 fore a fire is long in becoming hot. 
 
 A concave burning-mirror, which throws the rays of 
 heat to a focus or point, may be made of sheet-tin, by 
 
 Fi£. 294. 
 
 beating it out concave so as to fit a regularly curved 
 gauge. If a foot in diameter, and carefully made, it will 
 condense the rays of heat so powerfully at the focus, when 
 held several feet from the fire, as to set fire to a pine stick 
 or to flash gunpowder (fig. 294). 
 
 The reflection of radiated heat may be beautifully ex- 
 hibited by using two such concave tin mirrors. Place 
 them on a long table several feet apart, and ascertain the 
 focus of each by means of the light of a candle. Then 
 place in the focus of one a red-hot iron ball, or a small 
 chafing-dish of burning charcoal. In the focus of the 
 
278 
 
 HEAT. 
 
 other place the wick of a candle with a small shaving of 
 phosphorus in it. The heat will be reflected, as shown by 
 
 Fig. 295. 
 
 the dotted lines (fig. 295), and, setting fire to the phos- 
 phorus, will light the candle. 
 
 If a thermometer be placed in the focus of one mirror 
 while the hot iron ball is in the other focus, it will rise 
 rapidly ; but if a lump of ice be substituted for the ball, 
 the thermometer will immediately sink, and will continue 
 to do so until several degrees lower than the surrounding 
 air ; because the thermometer radiates more heat to the 
 
 mirrors 
 
 , and then to the ice, than the ice returns. 
 
 DEW AND FROST. 
 
 All bodies are constantly radiating some heat, and if an 
 equal amount is not returned by others, they grow colder, 
 like the thermometer before the lump of ice. Hence the 
 reason that on clear, frosty nights, objects at the surface 
 of the earth become colder than the air that surrounds 
 them. The heat is radiated into the clear space above 
 without being returned ; plants, stones, and the soil thus 
 become cooled down below freezing, and, coming in con- 
 tact with the moisture of the air, it condenses on them 
 and forms dew, or freezes into white frost. Clouds return 
 or prevent the passage of the heat that is radiated, which 
 is the reason there are no night-frosts in cloudy weather. 
 A very thin covering, by intercepting the radiated heat, 
 will often prevent serious injury to tender plants. Even 
 
FEOST IN VALLEYS. 279 
 
 a sheet of thin muslin, stretched on pegs over garden 
 vegetables, has afforded sufficient protection, when those 
 around were destroyed. 
 
 FROST IN VALLEYS. 
 
 On hills, where the wind blows freely, it tends to re- 
 store to plants the heat lost by radiation, which is the 
 reason that hills are not so liable to sharp frosts as still 
 valleys. When the air is cooled it becomes heavier, and, 
 rolling down the sides of valleys, forms a lake of cold air 
 at the bottom ; this adds to the liability of frosts in low 
 places. The coldness is frequently still fuither increased 
 by the dark and porous nature of the soil in low places 
 radiating heat faster to the clear sky than the more com- 
 pact upland soil. 
 
 A knowledge of these properties teaches us the import- 
 ance of selecting elevated places for fruit-trees, and all 
 crops liable to be cut off by frost ; and it also explains 
 the reason that the muck or peat of drained swamps is 
 more subject to frosts than other land on the same level. 
 Therefore, corn and other tender crops upon such porous 
 soils must be of the earliest ripening kinds, so as to escape 
 the frosts of spring by late planting, and those of autumn 
 by early maturity. 
 
 REMARKABLE EFFECTS OF HEAT ON WATER. 
 
 The effects of heat and cold on water are of a very in- 
 teresting character. "Without its expansion in freezing, 
 the soil would not be pulverized by the frost of winter, 
 but would be found hard, compact, and difficult to culti- 
 vate in spring ; without its expansion into steam, the 
 cities which are now springing up, and the continents that 
 are becoming peopled, through the influence of rail-ways, 
 steam-ships, and steam manufactures, would mostly re- 
 
280 HEAT. 
 
 main unbroken forests ; without the crystallization of wa- 
 ter, the beautiful protection of plants by a mantle of snow, 
 in northern regions, would give place to frozen sterility ; 
 without the conversion of heat to a latent state in melt- 
 ing, the deepest snows would disappear in a moment from 
 the earth, and cause disastrous floods ; without its con- 
 version to a latent state in steam, the largest vessel of 
 boiling water would instantly flash into vapor. All these 
 facts show that an extraordinary wisdom and forethought 
 planned these laws at the creation ; and even what appears 
 at first glance as an almost accidental exception in the 
 contraction of bodies by cold, and which causes ice to 
 float upon water, preventing the entire masses of rivers 
 and lakes from becoming permanently frozen, furnishes 
 one out of an innumerable array of proofs of creative de- 
 sign in fitting the earth for the comfort and sustenance of 
 its inhabitants. 
 
APPENDIX. 
 
 SIMPLE APPARATUS FOR ILLUSTRATING MECHANICAL ' 
 
 PRINCIPLES. 
 
 For the assistance of lecturers, teachers, and home students, the fol- 
 lowing list is given of cheap and simple apparatus and materials for 
 performing most of the experiments described in the first part of this 
 work. These experiments, although simple, exhibit principles of much 
 practical importance. 
 
 1. Inertia apparatus, p. 12. The concave post or stand is sufficient, 
 the snapping being done by the finger, although a spring-snap performs 
 the experiment more perfectly. 
 
 2. "Weight with two hooks and fine thread, p. 13. 
 
 3. The inertia of falling hodies may be simply shown, and the pile- 
 engine illustrated, by placing a large wooden peg or rod upright in a 
 box of sand, and then dropping a weight upon its head at different 
 heights, which will drive the rod into the sand more or less, according 
 to the distance passed through by the falling weight. 
 
 4. A straw-cutter, so made that the fly-wheel can be easily taken off, 
 will show in a very striking manner the efficacy of this regulator of 
 force. 
 
 5. Two lead musket balls will exhibit the experiment in cohesion, 
 p. 27. Balls or lead weights with hooks may be separated by sus- 
 pending weights, to show the amount of force required to draAv them 
 asunder. Metallic buttons or plates an inch in diameter, with hooks, 
 will show the great strength needed to separate them when coated with 
 grease, p. 27. 
 
 6. Capillary tubes of different sizes, two straight small panes of glass, 
 and a vessel of water, highly colored with cochineal or other dye, to ex- 
 hibit capillary attraction. 
 
 7. Glass tube, piece of bladder, and alcohol, for experiment described 
 on p. 33. 
 
 8. The cylinder for rolling up the inclined plane, represented by 
 fig. 18, p. 34, may be very easily made by using a round pasteboard 
 box a few inches in diameter, and securing a piece of lead inside by 
 loops made with a needle and thread. The object shown by fig. 19 
 may be cut in one piece out of a pine shingle, the centre rod being 
 lengthwise with the grain ; the two extremities are shaved small, and 
 wound with thick sheet-lead, and the whole then colored or painted a 
 
 281 
 
282 APPENDIX. 
 
 dark hue, to render the lead inconspicuous. The experiment with the 
 penknives, p. 35, is very simple, care being taken to insert them low 
 enough in the stick. 
 
 9. Irregular pieces of board, variously perforated with holes, and fur- 
 nished with loops to hang on a pin, may be used to determine the centre 
 of gravity, according to the principle explained by fig. 21, p. 35. 
 
 10. Portions of plank and blocks of wood, with the centre of gravity 
 determined as in the last experiment, may have a plumb-line (which 
 may be a thread and small perforated coin) attached to this centre, and 
 then be placed on differently inclined surfaces, to show their upsetting 
 just as this line of direction falls without the base. Toy-wagons, bought 
 at the toyshops, may be variously loaded and used in experiments of 
 this sort. 
 
 11. Experiments with the lever of the first kind may be easily per- 
 formed by the use of a flat wooden bar, two or three feet in length, 
 marked into inches, and placed on a small three-cornered block as a 
 fulcrum. Weights, such as are used for scales, may be variously 
 placed upon the lever. Levers of the second and third kind, which are 
 lifted instead of borne down, may have a cord attached to the point 
 where the power is to be applied, running up over a pulley or wheel, 
 with a weight suspended to the other end. 
 
 12. An axle, furnished with wooden wheels with grooved edges, of 
 different sizes, may be used to exhibit the principle of the wheel and 
 axle, in connection with scale-weights that are furnished with hooks. 
 The power of combined cog-wheels may be shown by a combination 
 like that represented on p. 57, using weights for both cords. 
 
 13. Interesting experiments with the inclined plane, at different de- 
 grees of slope, by a contrivance similar to that represented by fig. 96, 
 p. 83, with the addition of a small wheel at the upper side for a cord to 
 pass over. This cord is fastened at one end to a light toy-wagon, run- 
 ning up and down the plane, and at the other to a weight suspended 
 perpendicularly just beyond the upper edge of the plaue. The wagon 
 is variously loaded with weights, to counterpoise the suspended weight 
 at different degrees of inclination. 
 
 14. A lecturer may quickly demonstrate before a class the small in- 
 crease in the length of a road, in consequence of a considerable curve 
 to one side of a straight line (as shown by fig. 69), by using a cord for 
 measuring, the diagram being marked on a board or the wall. 
 
 15. A round stick of wood, and a long, wedge-shaped slip of paper, 
 easily show the principle of fig. 75, p. 70. 
 
 16. A cog-wheel with endless screw and winch (fig. 77, p. 71), exhibits 
 distinctly the great power of the screw in this combination. 
 
 17. Pine sticks, two feet long, and one-fourth to one-half inch through, 
 of different shapes and sizes, supported at each end, and with weights 
 hung at the middle till they break, may be made to illustrate the princi- 
 ples described on pp. 80, 81. 
 
 18. Some of the manciples of draught may be shown, and especially 
 
APPARATUS FOR EXPERIMENTS. 283 
 
 those in relation to the different angles of inclination for hard and soft 
 roads, by using a common spring-balance as a dynamometer, attached 
 to a hand-wagon, and also to a sliding block of wood. 
 
 19. Bent glass tubes, with arms of different sizes, to indicate the up- 
 ward pressure of liquids, may be procured cheaply at glass-works. The 
 experiment described by fig. 231, p. 204, may be rendered easy and inter- 
 esting by purchasing a large and perfectly-working syringe, and attach- 
 ing to its nose, by means of sealing wax, a slender glass tube two or 
 three feet long. Fill the syringe with water, leaving the tube empty ; 
 then, with the tube upright, drive the water up through it with the pis- 
 ton of the syringe, and the increased weight felt on the piston as the 
 column of water rises will be very evident. 
 
 20. A hydrostatic bellows a foot in diameter, made by any good 
 mechanic, will answer the purpose well, and exhibit an important prin- 
 ciple! 
 
 21. Specific gravities may be shown before a class by a common 
 balance and a fine cotton or silk thread. 
 
 22. A tin pail, with a hole half an inch or an inch in diameter at the 
 bottom, will show the contracted stream which pours from it, p. 212. 
 A short tin tube, with a slight flange at the upper end (quickly made 
 by any tin-worker), fitted into this hole, will increase the discharge, as 
 shown by figs. 236, 237, and the difference in time for emptying the ves- 
 sel may be measured by a stop-watch. 
 
 23. Archimedes' screw is readily made by winding a lead pipe rouud a 
 wooden cylinder. 
 
 24. A glass syphon, filled with cochineal water, shows distinctly the 
 theory of waves, by blowing with the mouth into one end. 
 
 25. Any vessel, filled with saud which has been heated over a fire, 
 with rods of different substances, nearly of an equal size and length, 
 and thrust with one end into the hot sand, in an inclined or nearly hori- 
 zontal position, will exhibit the various conducting powers of these 
 rods b) r melting pieces of wax or tallow placed on the ends most remote 
 from the sand. 
 
 26. The expansion by heat may be demonstrated by fitting an iron 
 rod to a hole in sheet-iron ; on heating the bar it can not be made to 
 enter. Or, if a hot iron ring be slipped on a tapering cold iron rod, it 
 will contract on cooling so that the force of a man can not withdraw the 
 rod. 
 
 27. The rising and descending currents in a vessel of heating water 
 are easily rendered visible by throwing into a glass vessel, or flask, over 
 a lamp, particles of sawdust from any hard, greeu wood, whose specific 
 gravity is about the same as that of water. 
 
 28. Instrument figured on p. 265, for showing the principle of the 
 steam-engine. 
 
 29. Experiments in latent heat may be easily exhibited with the as- 
 sistance of a common thermometer. 
 
 30. Tin mirrors for showing radiation, p. 278. 
 
284 APPENDIX. 
 
 DISCHARGE OF WATER THROUGH PIPES. 
 
 Table showing the amount of water discharged per minute through 
 an orifice one inch in diameter ; also through a tube one inch in diame- 
 ter "and two inches long, according to experiment. To ascertain the 
 amount in gallons, divide the cubic inches by 231. 
 
 Height of head Amount discharged Amount discharged 
 
 of water. through Orifice. through Tube. 
 
 1 Paris foot* 2,722 cub. in. 3,539 cub. in. 
 
 2 " 3,846 " 5,002 " 
 
 3 " 4,710 " 6, 6 " 
 
 4 " 5,436 " 7,070 " 
 
 5 " 6,075 " 7,900 
 
 6 " 6,654 " 8,654 
 
 7 " 7,183 " 9,340 " 
 
 8 " 7,672 " 9,975 " 
 
 9 " 8,135 " 10,579 " 
 
 10 " 8,574 " 11,151 " 
 
 11 " 8,990 " 11,693 " 
 
 12 " 9,384 " 12,o 5 " 
 
 13 " 9,764 " 12,699 " 
 
 14 " 10,130 " 13,177 " 
 
 15 " 10,472 " 13,620 " 
 
 VELOCITY OF WATER IN PIPES. 
 
 The following table shows the height of a head of water required to 
 overcome the friction in horizontal pipes 100 feet long, and to produce a 
 certain velocity, according to Smeaton : 
 Bore of 
 
 Pipes. 
 
 6 Inches. 
 
 lfOOt. 
 
 IVzfeet. 
 
 2/eet. 
 
 Zfeet. 
 
 4feet 
 
 5 feet. 
 
 in. 
 
 in. 
 
 in. 
 
 in. 
 
 ft. 
 
 in. 
 
 ft. in. 
 
 ft. 
 
 in. 
 
 ft. in. 
 
 K 
 
 4.5 
 
 16.7 
 
 35.1 
 
 4 
 
 9.7 
 
 10 1.0 
 
 17 
 
 10.0 
 
 28 0.2 
 
 % 
 
 3.0 
 
 11.1 
 
 23.3 
 
 3 
 
 2.5 
 
 6 8.6 
 
 11 
 
 10.6 
 
 18 8.1 
 
 l 
 
 2.2 
 
 8.4 
 
 17.5 
 
 2 
 
 4.9 
 
 5 0.5 
 
 8 
 
 11.0 
 
 14 0.0 
 
 IK 
 
 1.8 
 
 6.7 
 
 14.0 
 
 1 
 
 11.1 
 
 4 0.4 
 
 7 
 
 1.6 
 
 11 2.5 
 
 IK 
 
 1.5 
 
 5.6 
 
 11.7 
 
 1 
 
 7.2 
 
 3 4.3 
 
 5 
 
 11.3 
 
 9 4.1 
 
 1% 
 
 1.3 
 
 4.8 
 
 10.0 
 
 1 
 
 4.5 
 
 2 10.6 
 
 5 
 
 1.1 
 
 8 0.1 
 
 2 
 
 1.1 
 
 4.2 
 
 8.7 
 
 1 
 
 2.4 
 
 2 6.2 
 
 4 
 
 5.5 
 
 7 0.0 
 
 2U 
 
 1.0 
 
 3.7 
 
 7.8 
 
 1 
 
 0.8 
 
 2 9.9 
 
 3 
 
 11.6 
 
 6 2.7 
 
 2K 
 
 0.9 
 
 3.3 
 
 7.0 
 
 
 
 11.5 
 
 2 0.2 
 
 3 
 
 6.8 
 
 5 7.2 
 
 3 
 
 0.7 
 
 2.8 
 
 5.0 
 
 
 
 9.6 
 
 1 8.2 
 
 2 
 
 11.7 
 
 4 8.0 
 
 3K 
 
 0.6 
 
 2.4 
 
 5.0 
 
 
 
 8.2 
 
 1 5.3 
 
 2 
 
 6.6 
 
 4 0.0 
 
 4 
 
 0.6 
 
 2.1 
 
 4.4 
 
 
 
 7.2 
 
 1 3.1 
 
 2 
 
 2.7 
 
 3 6.0 
 
 * A Paris foot is about 12 4-5 U. S. inches, and 15 Paris feet are about 
 16 U. S. feet. 
 
RULE FOR THE DISCHARGE OF WATER. 285 
 
 Look for the velocity of the water per second in the pipe, in the up- 
 per line ; and in the column beneath it, and opposite the given diameter 
 of the pipe, is the height of the columu or head required to obtain the 
 required velocity. 
 
 To find the quantity of water discharged each minute, multiply the 
 velocity by 12, which will give the inches per second ; then multiply 
 this product by 60, which will give the inches per minute ; then, to 
 change these cylindrical inches into cubic inches, multiply by 4 and 
 divide by 5.* Divide the cubic inches by 231, and the result will be 
 gallons. 
 
 Bj T comparing this table with the next preceding, we shall perceive 
 that the water flows from three to four times as fast through the tube 
 two inches long, as through a tube one hundred feet long, the diameter 
 of the tube and the head of water being the same. 
 
 RULE FOR THE DISCHARGE OF WATER. 
 
 The following general formula or rule, applicable to different cases, 
 has been furnished by a practical engineer. It may be useful in ascer- 
 taining the quantity required to fill the driving pipe of a water-ram, and 
 for various other purposes occasionally occurring in practice. 
 
 Let A represent the fountain or reservoir from which water is to be 
 conveyed to the trough B through the pipe L. Let // be the height of 
 the surface of the water in the reservoir, above the place of discharge, 
 L the length of the tube in feet, and let D be the diameter of the tube 
 in the smallest part. It is required to find the quantity, §, which will 
 be discharged in a second of time. The length and height being given 
 in feet, and the diameter of the tube in inches, the formula, when the 
 quantity is required in gallons, is as follows : 
 
 Q = 0.608 V^ D l) 
 
 • This gives the cubic inches very nearly ; but, to be more accurate, multiply 
 the decimal .7854, which represents the difference between the area of a square 
 and of a circle. 
 
286 
 
 APPENDIX. 
 
 In order to make the above formula more intelligible : 
 Let L = SO rods or 1320 feet. 
 " H = 50 feet, 
 " D = 2 inches. 
 " Q = gallons. 
 
 Then Q =0.60S i / (32x-,f|o) = 0.67; or, the same maybe thus ex- 
 pressed in words : 
 
 Divide the height (50) by the length (1320) ; multiply the quotient by 
 the fifth power of the diameter (fifth power of 2 = 32) ; extract the 
 square root of the product, which, being multiplied by 0.608, will give 
 (0.67) the number of gallons the tube will discharge in one second ; 
 which, in this case, is 40 gallons in one minute. 
 
 VELOCITY OF WATER IN TILE DRAINS. 
 
 An acre of laud in a wet time contains about one thousand spare 
 hogsheads of water. An underdrain will carry oft' from a strip of land 
 about two rods wide, and one eighty rods long will drain an acre. The 
 following table will show the size of the tile required to drain an acre in 
 two days' time, (the longest admissible), at different rates of descent, or 
 the size for any larger area : 
 
 Rate of Descent. 
 
 1 foot in 100 
 
 1 foot in 50 
 
 1 foot in 20 
 
 1 foot in 10 
 
 1 foot in 100 
 
 1 foot in 50 
 
 1 foot in 20 
 
 1 foot in 10 
 
 1 foot in 100 
 
 1 foot in 50 
 
 1 foot in 20 
 
 1 foot in 10 
 
 A deduction of one-third to one-half must be made for the roughness 
 of the tile or imperfection in laying. The drains must be of some 
 length, to give the water velocity, and these numbers do not, therefore, 
 apply to very short drains. 
 
 iameter of Bore 
 
 2 iuches. 
 
 2 inches. 
 
 2 inches. 
 
 2 inches. 
 
 3 inches. 
 
 3 inches. 
 
 3 inches. 
 
 3 inches. 
 
 4 inches. 
 
 4 inches. 
 
 4 inches. 
 
 4 inches. 
 
 Velocity of 
 
 Hogsheads 
 
 Current per 
 
 discharged 
 
 second. 
 
 in 24 hours. 
 
 22 inches. 
 
 400 
 
 32 inches. 
 
 560 
 
 51 inches. 
 
 900 
 
 73 inches. 
 
 1290 
 
 27 inches. 
 
 1170 
 
 38 inches. 
 
 1640 
 
 67 inches. 
 
 3100 
 
 84 inches. 
 
 3600 
 
 32 inches. 
 
 2500 
 
 45 inches. 
 
 3500 
 
 72 inches. 
 
 5600 
 
 100 inches. 
 
 7800 
 
GLOSSARY 
 
 OF TERMS USED IN MECHANICS AND FARM MACHINERY. 
 
 Axis, a real or imaginary line, passing through a body, on which it is 
 supposed to revolve. 
 
 Axle or axle-tree, the bar of metal or timber, on the ends of which 
 the wheels of a carriage or wagon or other wheels revolve. 
 
 Babbett metal, an alloy, usually of tin and copper, for casing the 
 supports of journals, either for repair, or for easier running. 
 
 Back furrow, to throw the earth from two plow -furrows together. 
 
 Ball-cock, a self-regulating stop-cock, closed or opened by the rising 
 or falling of a floating hollow ball. 
 
 Ball-valve, a valve consisting of a loose ball, fitting closely, pre- 
 vented from moving beyond a certain limit. 
 
 Band-wheel, a wheel in machinery on which a band or belt runs. 
 
 Beam, the main lever of a steam-engine, turning on the centre, with 
 the piston rod at one end, and the working-rod at the other. Also, the 
 main timber or bar of a plow. 
 
 Bearing, the part of a shaft or spindle which is in contact with the 
 supports. 
 
 Bed, the foundation on which a fixed machine rests, as "the bed of an 
 engine." 
 
 Bell-crank, a crank resembling that by which the direction of a bell- 
 wire is changed. 
 
 Bevel-gear, the gearing of cog-wheels placed obliquely together, or 
 with the two axes forming an angle. 
 
 Bolster, the cross-bar of a wagon, resting on the axle, holding the 
 box, and through which the king-bolt passes. 
 
 Brake, a lever or other contrivance used for retarding the motion of 
 a wheel by friction against it. 
 
 Breast-wheel, a water wheel where the current is delivered upon it 
 about one-half or two-thirds its height, which distinguishes it from un- 
 dershot and overshot wheels. 
 
 Bridle, the forward iron on the beam of a plow, to which the team 
 is attached. 
 
 Brush-weeel, a wheel in light machinery, turned by friction merely, 
 instead of cogs ; bristles or brushes being often fixed to them to increase 
 the friction of their pressing surfaces. 
 
 Bush, the hollow box fitted into the centre of a wheel to take the 
 bearing of an axle or journal. 
 287 
 
288 GLOSSAET. 
 
 Cam, the projecting part of an eccentric or wavy wheel, to produce 
 alternate or reciprocating motion. 
 
 Cant-hook, a wooden lever with an iron hook near one end, used for 
 moving heavy articles, particularly saw-logs, etc. The end of the lever 
 is usually placed on the fulcrum, and the hook is fixed into the weight, 
 making it a lever of the second kind. 
 
 Capillary attraction, the attraction which causes liquids to rise in 
 very small tubes, or which retains water among sand and the particle? 
 of soil. 
 
 Centre of gravity, that point in a body or mass of matter, arouno 
 which all parts exactly balance each other. 
 
 Centrifugal force, tending to fly from the centre, as the stone from 
 a sling. 
 
 Centripetal force, drawing towards the centre, like the cord of a 
 sling. 
 
 Chamfer, a slope, channel, or groove, cut in wood or metal. 
 
 Chase, a wide groove. 
 
 Chilled, applied to cast-iron rendered harder by casting the melted 
 metal against cold metal in the mould, for rendering certain parts harder 
 which are most liable to become worn. 
 
 Chine, the ends of the staves of a barrel, outside the heads. 
 
 Clamp, a cross-bar used to give additional strength, or to prevent 
 warping. Also, a piece of metal or wood, generally resembling in shape 
 the letter U, furnished with a screw, to fasten objects to a table or other 
 fixed bodies, or to each other. 
 
 Cleat, a piece of wood nailed across, to give strength or security. 
 
 Clevis, a draught iron, usually somewhat in the form of a bow or let- 
 ter U, placed on the forward end of a plow-beam for draught, or for 
 similar purposes. 
 
 Click, a pawl, a latch, or the ratchet of a wheel. 
 
 Cog, the tooth or projection of a cog-wheel. 
 
 Collar, a metal ring around the end of a cylinder of wood to prevent 
 splitting, or a ring around a piston or a journal, for securing tightness 
 or steadiness. 
 
 Colter or Coulter, the upright cutting iron of a plow. 
 
 Compass, an instrument for describing circles, measuring distances^ etc. 
 
 Counter-sink, a cavity made to receive the head of a screw. 
 
 Coupling-box, a contrivance for connecting shafts, or throwing 
 wheels in and out of gear. 
 
 Crab, a small portable crane. 
 
 Cradle, a scythe with fingers, for cutting grain by hand. 
 
 Crane, a machine for raising weights and then swinging them side- 
 wise ; generally made by attaching a pulley to a swinging bar or frame. 
 
 Crank, an axle with a crooked portion for changing a rotary to an 
 alternate motion, or the reverse. A three-throw crank has three bends, 
 for driving three pumps, each stroke separated from the others by the 
 
GLOSSARY. 289 
 
 third of a revolution, thus making a regular and uniform application of 
 the force. 
 
 Cross-cut Saw, a large saw worked by a man at each end, for cutting 
 logs. 
 
 Cutter-bar, the cutting apparatus of a mowing or reaping machine. 
 
 Cycloid, a curve made by any point in a circle rolling on a straight 
 line, and marking the curve on a plane surface at the side of the circle. 
 A rail driven in the rim of a wagon-wheel, driven through a snow bank, 
 will mark a cycloid on the snow. An epicycloid is made by a similar 
 revolution of a circle, rolling on the circumference of another circle, 
 externally or internally. 
 
 Dead centre, a centre which does not revolve. 
 
 Dead furrow, the furrow where the plow throws the earth in oppo- 
 site directions, or where the furrows meet in plowing a strip of land. 
 
 Derrick, a pole or upright timber for supporting a crane, used in lift- 
 ing heavy materials in building and for other purposes. 
 
 Dog, an iron catch or clutch, driven into the end of a saw-log, to hold 
 it in a fixed position while sawing. 
 
 Double-tree, the central wbiffle-tree of a two-horse set. 
 
 Dowel, a short iron or wooden pin to join two pieces of timber, pro- 
 tecting from one timber into a hole in the corresponding one. A 
 familiar example occurs in the manner in which a cooper secures two or 
 more boards in forming the head of a cask. 
 
 Draught, Angle of, the angle made by a line of draught with a line 
 drawn on ,he surface over which the body is drawn. 
 
 Dredge, or Dredging Machine, a machine for scooping up mud or 
 earth from under water; for clearing the channels of canals, rivers, and 
 harbors. 
 
 Drill, a furrow for the reception of seed, or a row of growing plants ; 
 also a machine for sowing seed in continuous rows. 
 
 Driving-wheel, the wheel of a mowing or reaping machine, which 
 runs on the ground, and propels the gearing. 
 
 Drum, a revolving cylinder, around which belts or endless straps are 
 passed, to communicate motion. 
 
 Dynamics, the science of motion and forces. 
 
 Dynamometer, an instrument for measuring forces, applied to plows, 
 mowing machines, thrashing machines, etc., to show the amount of 
 force required to work them. 
 
 Eccentric, out of centre; applied to wheels, discs, or circles, with 
 the axle out of centre, to create reciprocating motion. Eccentric rod is 
 the rod that transmits the motion of the eccentric wheel. 
 
 Elevator, an endless revolving leather strap, set with sheet-iron 
 boxes or cups, for raising grain. The term is also applied to buildings 
 into which grain is thus elevated and stored. 
 
 Emery wheel, a wheel set with emery at the circumference, for 
 grinding or polishing metals. 
 
 Endless chain, a chain with the ends connected together, running on 
 
 in ' 
 
290 GLOSSARY. 
 
 two drums or cylinders ; as in the endless chain or tread-powers to 
 thrashing machines. 
 
 Endless screw, a screw working in a toothed wheel or cog-wheel, 
 and imparting a motion to the wheel equal to the advance of one tooth 
 to each revolution of the screw. 
 
 Epicycloid, see Cycloid. 
 
 Epicycloidal wheel, a wheel with cogs on its interior rim, fitting 
 into another cog-wheel precisely one-half its diameter, for converting 
 circular into alternate motion ; any point in the circumference of the 
 smaller wheel, while in motion, describing a straight line. 
 
 Evener, the central or larger whiffle-tree of a set of whiffie-trees for 
 two horses, called also a double-tree. 
 
 Fan, the vane of a wind-mill, to keep the sails facing the wind. 
 
 Feather, the thin cutting part of a plowshare, on the right-hand side. 
 
 Felloe, or Felly, the circumference or rim of a wheel, or a segment 
 of it, into which the spokes are inserted. 
 
 Ferrule, a ring or hand on the end of a wooden rod or bar, to pre- 
 vent splitting. 
 
 Female screw, a hole cut with the threads of a screw, into which a 
 screw fits. 
 
 Finger-bar, that portion of the cutting-bar of a mowing or reaping 
 machine, in which the knife-bar works. 
 
 Flange, a projection from the end of a pipe or from any piece of 
 mechanism, so as to screw to another part ; a term also applied to the 
 projection of a car-wheel to keep it from running off the rail. 
 
 Flash- wheel, a water-wheel used for elevating water, resembling a 
 breast-wheel with a reversed motion. 
 
 Float-board, one of the boards forming the exterior of a water- 
 wheel, against which the stream of water dashes. 
 
 Flume, the water passage of a mill, usually a box of plank. 
 
 Fly-wheel, a wheel with a heavy rim, for retaining inertia and equal- 
 izing the motion of machinery. 
 
 Foot-valve, a valve in a steam-engine, opening from the condenser 
 towards the air-pump. 
 
 Force-pump, or Forcing-pump, a pump with a solid piston, which 
 drives instead of sucking water. 
 
 Friction-wheel, made by two wheels overlapping each other, and 
 bearing between them the axle or journal of another wheel, thus dimin- 
 ishing the friction of the latter. 
 
 Fulcrum, a support ; applied to the support used for the lever, in 
 raising weights. 
 
 Furrow slice, the strip of earth thrown out by the plow at a passing. 
 
 Furrows, plat and lapping; when the slice is laid flat or level, and 
 when the edge of one overlaps the preceding, respectively. 
 
 Gang-plow, a compound plow made of a series of plows running side 
 by side. 
 
 Gavel, a sheaf of grain reaped but not bound. 
 
GLOSSARY. 291 
 
 Gearing, a series of cog-wheels working together. 
 
 Governor, a self-regulator of a steam-engine, so constructed that 
 centrifugal force throws up weights When the engine runs too fast, and 
 partly closes the admission pipe of steam ; and, dropping again when it 
 runs too slow, opens the steam pipe. 
 
 Gravitation, the attraction between bodies in mass, as distinguished 
 from cohesion between the particles; the force which causes bodies to fall 
 by the attraction of the earth. 
 
 Guard, one of the fingers in the cutting apparatus of a mowing or 
 reaping machine, for protecting the knives from injury from external ob- 
 jects. Open Guard has an opening above the knives, to prevent clog- 
 ging. 
 
 Hat-tedder, a niachiue for spreading and turning hay. • 
 
 Header, a reaping machine which cuts the heads of the grain and 
 leaves most of the straw standing. 
 
 Head-land, the strip or border of unplowed land left at the ends of 
 the furrows. 
 
 Hound, the forward portion of a wagon, to which the tongue is at- 
 tached. 
 
 Hydraulic Ram, see Ram. 
 
 Hydraulics, the science of water in motion, or the laws of motion 
 and force as applied to running water, and to machinery driven by it. 
 
 Hydrodynamics, the laws of motion and force, as applied to liquids, 
 both in motion and at rest, and embracing Hydraulics and Hydrostatics. 
 
 Inclined plane, a plane or surface deviating more or less from a 
 level. if 
 
 Inertia, the property or force of matter by which it retains its state 
 of motion or rest, — requiring force to start a body at rest or to stop one 
 in motion. 
 
 Jack, an engine or machine for raising heavy weights. 
 
 Jack-screw, a strong iron screw for raising timbers, buildings, etc. 
 
 Journal, the portion of a shaft or axle which revolves on a support. 
 
 Kerf, the opeuing or slit made by the passage of a saw. 
 
 Key, a wedge of wood or metal driven iuto a mortise or opening, to 
 secure two parts together. 
 
 Knee-joint, or Toggle-joint, a contrivance for exerting power or 
 pressure, by straightening a double bar with a joint like that of the knee. 
 
 Land, a term applied to the oblong portion of a field around which 
 the team passes in plowing, the field being usually divided into several 
 lands for this purpose. The term is also applied to the side of a plow 
 opposite the mould board, and a plow is said to run to land when it takes 
 too wide a furrow-slice. 
 
 Land-side, the side of that portion of a plow which runs in the 
 soil, opposite the mould-board, and next the unplowed portion of ground. 
 
 Lantern-wheel, a pinion made of two small wheels connected by 
 parallel rods which form the teeth. 
 
292 GLOSSARY. 
 
 Lever, a bar or rod for raising weights, resting on a point called a 
 fulcrum. 
 
 Lever-power, see Sweep-power. 
 
 Male screw, a screw with a spiral thread, fitting into a hole with cor- 
 responding threads called a female screw. 
 
 Mechanical powers, the simple machines or elements of machinery, 
 consisting essentially of the Lever and Inclined Plane ; the lever com- 
 prising the Wheel and Axle and the Pulley, and the inclined plane com- 
 prising the Wedge and the Screw. 
 
 Mash, or Mesh, to interlock, as the teeth of cog-wheels. 
 
 Mechanics, the science that treats of forces and powers, and their 
 action on bodies, and particularly as applied to the construction of ma- 
 chines. 
 
 Mitre, to cut to an angle of 45 degrees, so that two pieces joined 
 shall make a right angle. 
 
 Momentum, impetus ; the force of a moving body. 
 
 Monkey, an apparatus for disengaging and securing again the ram of 
 a pile-engine. 
 
 Mortise, a hole cut to receive the end or tenon of another piece. 
 
 Nut, a piece of iron furnished with a screw-hole, used on the end of a 
 screw for securing the parts of machinery. 
 
 Overshot wheel, a water-wheel, the circumference of which is fur- 
 nished with cavities or buckets, into which the stream of water is deliv- 
 ered at the top, turning the wheel by its weight. 
 
 Pall, or Pawl, the catch of a ratchet-wheel ; a click. 
 
 Pent-stock, an upright flume. 
 
 Perambulator, a measurer of distances, consisting of a wheel, and 
 index to show by wheelwork the number of its turns. 
 
 Percussion, Centre op, that point of a moving body at which its im- 
 petus is supposed to be concentrated. 
 
 Pile-driver, or Pile-engine, an engine for driving piles into the 
 ground, effected by repeatedly dropping a heavy weight on the heads of 
 the piles ; used mostly in swamp or water when the bottom is mud. 
 
 Pinion, a small-toothed wheel, working in the teeth of a larger one. 
 
 Pitch, the distance between the centres of two contiguous cog-wheels. 
 
 Pitch line, the circle, parallel with the circumference, which passes 
 through the centres of the teeth of a wheel. 
 
 Pitman, a rod connected with a wheel or crank, to change rotary to 
 reciprocating motion, or the reverse. 
 
 Planet-wheels, two elliptical wheels connected by teeth running 
 into each other, and revolving on their foci. 
 
 Plow-beam, the main timber of a plow, by which it is drawn. 
 
 Plow-share, the front part beneath the soil, which performs the cut- 
 ting — sometimes called plow-s7we, or plow-point. 
 
 Plunger, the piston of a forcing pump. 
 
 Pneumatics, the science treating of the mechanical properties of air. 
 
 Pole, the tongue of a reaping or other machine. 
 
GLOSSARY. 293 
 
 Power, the moving force of a machine, as opposed to the weight, 
 load, or resistance of the substance wrought upon ; also called prime 
 mover. 
 
 Projectile, a body thrown through the air. 
 
 Pulley, one of the mechanical powers, consisting of a grooved wheel 
 called the sheave, over which a rope passes ; the box in which the wheel 
 is set is called the block. The term is also applied to a fixed wheel over 
 which a band or rope passes. 
 
 Pump, a hydraulic machine for raising water; or one for withdrawing 
 air. The handle is called the brake. 
 
 Quantity of motion, the velocity of a moving body multiplied by its 
 mass. 
 
 Rabbet, to pare down the edge of a board or timber. 
 
 Rack, a straight bar cut with teeth or cogs, wprking into a correspond- 
 ing cog-wheel or pinion which drives or follows it. 
 
 Rag-wheel, a wheel with teeth or notches, on which nn endless or re- 
 volving chain usually runs. Also applied to a ratchet wheel. 
 
 Rake-head, the cross-bar of a rake, which holds the teeth. 
 
 Ram, Hydraulic ram, or Water-ram, a hydraulic machine or engine 
 for raising water to a height several times greater than that of the head 
 of water, by employing the momentum of the descending current in 
 successive beats or strokes. 
 
 Ratchet-wheel, a wheel cut with teeth like those of a saw, against 
 which a click or ratchet presses, admitting free motion to the wheel in 
 one direction, but insuring it against reverse motion. 
 
 Reach, the bar which connects the forward and rear axles of a wagon 
 or carriage. 
 
 Rea.m, to bevel out a hole. 
 
 Reciprocating motion, alternate motion, or a movement backwards 
 and forwards in the same path. 
 
 Reel, the revolving frame of a reaping machine, to throw the stand- 
 ing grain towards the knives. 
 
 Resolution of forces, dividing a force iuto two or more forces act- 
 ing in different directions ; rendering a compound force into its several 
 simple forces. 
 
 Resultant, a force produced by the combination of two or more 
 forces. 
 
 Safety valve, a valve opening outwards from a steam boiler, and 
 kept down by a weight, permitting the escape of steam when the press- 
 ure reaches a certain point, regulated by the degree of weight. The 
 term also applies to a valve opening inwards, and similarly regulated, to 
 prevent the pressure of the atmosphere from crushing in the boiler when 
 the steam cools and leaves a vacuum. 
 
 Scoop- wheel, a water-wheel with scoops or buckets around it, against 
 which the current dashes. 
 
 Screw-bolt, a bolt secured by a screw, or with a screw cut upon it. 
 
 Screw-propeller, an instrument for driving a vessel, by means of 
 
294 GLOSSAEY. 
 
 blades twisted like a screw, revolving beneath the water, the axis being 
 parallel with the keel. 
 
 Section, one of the knives or blades on the cutter-bar of a mowing 
 machine. 
 
 Self-raker, a contrivance attached to a reaping machine, to throw 
 off the cut grain in gavels, to obviate raking off by hand. 
 
 Shears, or Sheers, two poles lashed together like the letter X, for 
 placing under heavy poles, etc., in raisiug them; also to single vertical 
 poles supporting pulleys, for a similar purpose. 
 
 Sheave, the wheel of a pulley set in a block. 
 
 Shoot, or Shute, a passage-way down which grain, hay, or straw, is 
 slid or thrown. 
 
 Side-draught, the side pressure of a machine on the team which 
 draws it, as distinguished.from centre draught. 
 
 Single-tree, a single whiffle-tree, the cross-bar to which the traces of 
 a horse are attached, as distinguished from a double-tree, or two-horse 
 whiffle-tree. 
 
 Siphon, or Syphon, a bent tube for drawing off liquids ; the column 
 of liquid in the outer or longer leg overbalancing the inner column, 
 and producing a current. 
 
 Skein, the iron casing of a wagon-axle on which the wheel runs. 
 
 Skim-coulter, a coulter of a plow so constructed as to pare the sur- 
 face before the mould-board. 
 
 Skim-plow, the small forward mould-board of a double Michigan or 
 Sod-and-subsoil plow. 
 
 Slide-rest, the rest or support of the chisel in a turning lathe, made 
 to slide along the frame for cutting successively the different parts of the 
 work. 
 
 Slot, a slit or oblong aperture in any part of a machine, to admit an- 
 other part. 
 
 Snath, the handle or bar to which the blade of a scythe is attached. 
 
 Sod, the slice of earth cut by the passing of a plow. 
 
 Sole, the bottom plate under a horse-shoe tile, in draining. 
 
 Spindle, a small axle in machinery, as distinguished from a shaft or 
 large axle. 
 
 Spirit-level, a glass tube containing alcohol with an air-bubble, her- 
 metically sealed at both ends, the position of the bubble at the middle 
 showing the tube to be level. 
 
 Spur-wheel, or pinion, a cog-wheel with teeth parallel to the axle. 
 
 Standard, an upright supporting timber ; the front upright bar in a 
 plow to which the mould-board is fastened. 
 
 Steam chest, a box attached to the c} 7 linder of a steam-engine, in 
 which the sliding valves work. 
 
 Stirrup, an iron band encasing a wooden bar, for attaching to some 
 other part. 
 
 Stud, a short, stout support. 
 
GLOSSARY. 295 
 
 Subsoil-plow, a plow running below the furrow of a common plow, 
 for breaking up or loosening the subsoil or lower soil of a field. 
 
 Swage, to give shape to a substance by stamping with a die. 
 
 Sweep-power, a horse-power for driving thrashing and other ma- 
 chines, where the horses arc attached to a pole and walk in a circle. 
 
 Swingle-tree, also called" swing-tree, single-tree, whipple-tree, 
 and whiffle-tree ; the cross-bar to which traces are attached. 
 
 Swing-plow, a plow with no wheel under the beam. 
 
 Swivel, a ring and axis in a chain, to admit of its turning. 
 
 Swivel bridge, a bridge which turns round sideways on its centre. 
 
 Swivel plow, a side-hill plow, or a plow with a reversible mould-board. 
 
 Tackle, a pulley, or machine with ropes and blocks for raising heavy 
 weights. 
 
 Tail-race, the channel which carries off the water below a water 
 wheel. 
 
 Tedder, a machine for turning and spreading hay. 
 
 Thill, one of the shafts of a wagon between which the horse is put 
 — often corrupted to Fill. 
 
 Throttle- valve, a valve which turns at its centre on an axis — gener- 
 ally used to regulate the supply of steam to the cylinder of a steam-en- 
 gine. 
 
 Thumb-screw, a screw with its head flattened in the direction of its 
 length, so as to be turned with the thumb and finger. 
 
 Tide- wheel, a wheel adapted to currents flowing both ways — the float- 
 boards pointing from the centre. 
 
 Tine, the tooth or prong of a fork. 
 
 Tire, the iron band which binds together the fellies of a wheel. 
 
 Toggle-joint, or knee-joint, a mechanical power exerted by straight- 
 ening a double bar with a hinge at the middle or connection. 
 
 Torsion, the act of twisting by the application of lateral force. The 
 force of torsion is the elasticity of a twisted body, 
 
 Track-cleaner, an attachment to a mowing machine, to throw the 
 cut grass away from that which is uncut. 
 
 Traction, Angle of, the angle between the line of draught and any 
 given plane, as that of the earth's surface. 
 
 Trammel, an instrument used by carpenters for drawing an ellipse. 
 
 Tread-power, a machine on which the horse or other animal working 
 it walks. It may be either a horizontal or slightly inclined wheel ; or 
 an endless-chain power, the term being more frequently applied to the 
 latter. 
 
 Trench-plow, a plow cutting deep furrows and bringing the subsoil 
 up to the surface; as distinguished from a subsoil plow, which only 
 loosens the subsoil and leaves it below the surface. 
 
 Trundle-head, a wheel turning a mill-stone. 
 
 Tub-wheel, a horizontal water-wheel, driven by the percussion of the 
 stream against its floats, and not submerged in water. 
 
296 GLOSSARY. 
 
 3 the 
 
 Tumbler, a latch in a lock, which, by means of a spring, detains 
 bolt in its place until lifted by the key. 
 
 Tumbling rod, the rod which connects the motion of a horse-power 
 with that of a thrashing or other machine. 
 
 Turbine wheel, a horizontal water-wheel, so constructed that the 
 current strikes all the floats or buckets around the circumference at the 
 same time, thus imparting to it great power for its size. It is sub- 
 merged, the water escaping towards the centre and below, or above and 
 below together. 
 
 Undershot wheel, a water-wheel moved by the current striking 
 against the lower portion of its circumference. 
 
 Universal joint, a connecting joint between two rods, consisting of 
 a sort of double hinge, admitting motion in any direction. 
 
 Valve, a lid for closing an aperture or passage, so as to open only in 
 one direction. 
 
 Velocity, speed or swiftness; which may be uniform, or equal 
 throughout ; accelerated, or increasing ; or retarded, or rendered slower. 
 
 Virtual velocities, Principle of, that by which certain powers are 
 equal to each other, where the force and space moved over, whatever 
 these may be, are the same when multiplied together. 
 
 Washer, a circular piece of metal, pasteboard, or leather, placed be- 
 low a screw-head, or nut, or within a linch-pin, for protection. 
 
 Water-ram, see Ram. 
 
 Whiffle-tree, or Whipple-tree, the cross-bar to which the traces 
 of a horse are attached ; see Single-tree. 
 
 Whip-saw, a large saw, worked by a man at one end, with a wooden 
 spring at the other ; a cross-cut saw. 
 
 Winch, a bent handle or right-angled lever, for turning a wheel or 
 grindstone, or producing rotary motion for other purposes. 
 
 Windlass, a machine for raising heavy weights, by the winding of a 
 rope or chain on a horizontal axle, and turned by a winch or by levers. 
 
 Winrow, or Windrow, the ridge of hay raked up on a meadow. 
 
 Wrest, a partition which determines the form of the bucket in an 
 overshot wheel. 
 
INDEX 
 
 Air, Pressure of 239 
 
 u Mode of weighing 239 
 
 " Pump 240 
 
 " Hand fastened, by 241 
 
 " Motion of. 245 
 
 " Resistance of. 247 
 
 Alden's Cultivator 14G 
 
 Allen's Farm Mill 195 
 
 Altitudes measured by the Barome- 
 ter 243 
 
 American Hay-tedding Machine 165 
 
 Appai-atus for Experiments 281 
 
 Aqueducts of the Romans 199 
 
 Archimedean Root Washer 193 
 
 " Screw 217 
 
 Archimedes, would move the earth 
 
 with a lever 55 
 
 Artesian Springs and wells 201 
 
 Atmosphere, Height and Weight 
 
 of 239, 241 
 
 B 
 
 Bags, How to carry 41 
 
 Balance, a lever 47 
 
 Balls, Why they roll easily 38 
 
 Barometer 241 
 
 Bars of wood, Strength of. 79 
 
 Beardsley's Hay Elevator 177 
 
 Bellows, Hydrostatic 204 
 
 Bevel Wheels or Bevel Gear GO 
 
 Billings' Corn Planter 155 
 
 Binders for Reaping Machines 163 
 
 Boat, Compound motion of. 20 
 
 Broadcast Sower, Seymour's . .154 
 
 Brown's Wind-mill 251 
 
 Brush Harrow 142 
 
 Buckeye Mower 159 
 
 Bullard's Hay-tedding Machine 165 
 
 Bulk of a ton of different substances. 210 
 Burrairs Corn-sheller 191 
 
 C 
 
 Capillary attraction 31 
 
 " " its great import- 
 ance 32 
 
 Cayuga Chief Mower 160 
 
 " " Dropper 162 
 
 Cements, Effects of. 28 
 
 Centre of Gravity 34 
 
 " " curious examples 
 
 of ) 35 
 
 " how determined 35 
 
 Centrifugal Force 21 
 
 Chain Pump 221 
 
 Cheese Press 72 
 
 ." " Dick's 74 
 
 11 " Kendall's 73 
 
 Chimney Currents 253 
 
 " Caps 254 
 
 Chimneys, Construction of 254 
 
 " To prevent smoking 256 
 
 Churn with fly-wheel 17 
 
 " worked by dog-power 191 
 
 Cistern Pumps 219 
 
 Cisterns, To calculate contents of. .237 
 
 " Proper sizes for 238 
 
 Clod Crusher .149 
 
 " " Croskill's and Ameri- 
 can 150,151 
 
 Cog, Hunting 60 
 
 Cogs, Form of 58 
 
 " and Cog-wheels 58 
 
 Cohesion, Attraction of 27 
 
 " between lead balls 27 
 
 " weak in liquids 31 
 
 Complex Machines, objectionable.. 116 
 
 Compound motion 19 
 
 " " How to calculate. 20 
 
 Comstock's Rotary Spader. . . .148, 117 
 
 Conducting power of bodies 260 
 
 " " liquids 261 
 
 Corn Planter, Billings' 155 
 
 " Shelter, 'Burrairs 191 
 
 297 
 
 Q* 
 
298 
 
 INDEX. 
 
 Corn Sheller, Horse-power 192 
 
 Richards' 192 
 
 Corn Planters 155 
 
 Cost of Implements and Machines. 117 
 
 Cotton Gin, Emery's 196 
 
 Coulter for Plows 127 
 
 Crested Furrow-slice 126 
 
 Crosskill's Clod-crusher 150 
 
 Crow-bar, a simple power 43 
 
 Crown Wheels 60 
 
 Cubic foot of different substances, 
 
 Weight of 210 
 
 Cultivator, or Horse-hoe 145 
 
 Claw-toothed 146 
 
 Alden's Thill 146 
 
 " Duck-foot 146 
 
 " Two-horse 148 
 
 " Harrington's 157 
 
 Cutter for the Plow 127 
 
 " Bar in Mowers and Reapers. 158 
 
 B 
 
 Dederick's Hay-press 185 
 
 " Capstan 185 
 
 Deep-tiller Plow, Holbrook's 126 
 
 Deep Wells, Pump for 220 
 
 Dew and Frost 278 
 
 Discharge of water through pipes.. 284 
 
 " " Rule for 2S5 
 
 Ditches, Velocity of water in. .214, 286 
 " Leveling instruments for.. 115 
 
 Dog-power Churn 191 
 
 Draught, Combined 96 
 
 Draught of wheels, explained 37 
 
 " Line of 95 
 
 " Principles of 93 
 
 " How to measure 94 
 
 " of Plows 95 
 
 Drilling wheat 153 
 
 Drills, Hand 157 
 
 Drive-pump 220 
 
 Dropper, attachment to reapers 162 
 
 Dynamometer, applied to roads S5 
 
 " Construction and use 
 
 of 98 
 
 " Self-recording 101 
 
 " Waterman's 102 
 
 ■ " for rotary motion... 106 
 
 E 
 
 Elevators for Hay 173 
 
 Emerson's Chimney Cap 255 
 
 Emery's Horse-powers 1S8 
 
 Cotton Gin 196 
 
 Empire Wind-mill 251 
 
 Endless-chain power 1S8, 189 
 
 Engine, Garden. . : 230 
 
 Experiments, apparatus for 281 
 
 F 
 
 Falling Bodies, Velocity of 23 
 
 " " Resistance of air on 25 
 
 " " in vacuo 25 
 
 Farm, Seventy-thousand-acre 8 
 
 " implements, Construction 
 
 and use of. 115 
 
 " implements, Cost of 117 
 
 " mills 195 
 
 Finger-bar in mowers and reapers.. 15S 
 
 Flail, Old sort 187 
 
 " Estimate of comparative work 
 
 with 187 
 
 Flash-wheel 231 
 
 Flea, power of leaping 115 
 
 Fly-wheel 16 
 
 " used on horse-pump 16 
 
 Forcing-pump 223 
 
 Fork Handles, Proper form of 76 
 
 Forsman's Farm Mill .195 
 
 Friction '. 81 
 
 " Nature of 82 
 
 " How to Measure 83 
 
 " not influenced by velocity. 88 
 
 " of axles 89 
 
 " of wheels . 90 
 
 " Lubricating substances for. 91 
 
 " Advantages of 92 
 
 Frost and Dew 278 
 
 " in valleys 279 
 
 Fuel, Green wood for 275 
 
 Furrow-slice, Crested 126 
 
 Furrows, Lapping and flat 127 
 
 G 
 
 Galileo's experiment on falling bod- 
 ies 26 
 
 Garden Engine 230 
 
 Garrett's Horse-hoe 147 
 
 Geddes' Harrow 143 
 
 Gladding's Hay -fork 175 
 
 Glossary of terms 287 
 
 Gravitation 23 
 
 Gravity, Centre of. 34 
 
INDEX. 
 
 299 
 
 Gravity, Specific, how measured.. .208 
 " "of different sub- 
 stances 200 
 
 Green wood for fuel , 274 
 
 H 
 
 Hand-drills 157 
 
 " rakes, sulky 160 
 
 Harrington' s Seed sower 157 
 
 " Cultivator 157 
 
 Harrow, Norwegian 144 
 
 " Morgan 144 
 
 " Scotch, or square 143 
 
 Harvester, Marsh's 163 
 
 Hay-forks, Horse. 173 
 
 " carriers 180 
 
 " loaders 186 
 
 " rake, Revolving 168 
 
 " " Warner's 169 
 
 " rakes 166 
 
 " Simple 167 
 
 " stacking machine 184 
 
 " tedder, Bullard's 165 
 
 " " American.. 166 
 
 " presses 184 
 
 " sweep 171 
 
 Headers 163 
 
 Heat, Properties of. 260 
 
 " Expansion by 263, 271 
 
 " Latent 273 
 
 " Radiation of 276 
 
 Hicks' Hay -carrier 180 
 
 High pressure steam-engines 269 
 
 Hoe-handle, Proper form of 77 
 
 Holbrook's Plow 125 
 
 " Swivel or side-hill Plow.133 
 Horse, day's work at different de- 
 grees of speed 110 
 
 " hoe, Garrett's 147 
 
 " power, Estimating 109 
 
 " Hay-forks, Operation of 174 
 
 fork, Gladding's 175 
 
 " " Palmer's 176 
 
 " " Myers' 177 
 
 " " Beardsley's 177 
 
 " " Raymond's 178 
 
 " " Harpoon 179 
 
 " Walker's 179 
 
 " Sprout's 179 
 
 Hydraulic Ram 226 
 
 " " Regulating 227 
 
 Hydrostatic Paradox 203 
 
 Hydrostatic Bellows 204 
 
 " Press 203 
 
 Hydrostatics , 198 
 
 I 
 
 Implements required for the farm. . 7 
 
 9,117 
 
 " Construction and use 
 
 of 115 
 
 Improvements in Farm Machinery. 8 
 
 Inclined Plane 63 
 
 Inertia 11 
 
 " apparatus 12 
 
 M Effects of, on wagons 13, 17 
 
 J 
 
 Joint, Universal 60 
 
 K 
 
 Kirby Mower and Reaper 159 
 
 " Reaper, Hand-rake for 160 
 
 " " Self-raking 161 
 
 Knee-joint, or Toggle-joint 71 
 
 Knives in mowers and reapers, 
 
 Form of 158 
 
 Kooloo Plow 118 
 
 I< 
 
 Labor, Application of 108 
 
 " of men and horses 110 
 
 Ladders, Self-supporting 40 
 
 Lapping and flat furrows 127, 128 
 
 Latent heat 273 
 
 " " Advantages of. 275 
 
 Law of virtual velocities 43 
 
 Leveling Instruments 215 
 
 Levers 45 
 
 " of the second kind 45 
 
 " " first kind 46 
 
 • « " third kind 46 
 
 " Calculating power of. — 49,50 
 
 " Examples of. 46 
 
 " Combination of 50 
 
 Line of direction 36 
 
 Liquids, Velocity of, in falling 211 
 
 " Discharge through pipes. .212 
 
 Loads on sideling roads 37 
 
 Lubricating substances 90 
 
300 
 
 INDEX. 
 
 M 
 
 Machinery iu connection with water.198 
 
 Machines, Advantages of 42 
 
 11 Models of 113 
 
 " Complex, objectionable. .116 
 " Construction and use of. .115 
 " Required for the Farm. 7, 
 
 9,117 
 
 Marsh's Harvester 163 
 
 Materials, Measuring strength of. .. 29 
 
 Mechanical powers 42 
 
 " principles, Advantages 
 
 of 10 
 
 Mechanical principles, Application 
 
 of 75 
 
 Models of machines 113 
 
 Moline Plow 120 
 
 Momentum 14 
 
 " Calculating quantity of.. 18 
 
 " of railway trains 18 
 
 Moorish Plow 118 
 
 Morgan's Harrow 144 
 
 Motion, Compound 19 
 
 Mouldboard of the Plow, Form of. .124 
 Mountains, Height of, measured by 
 
 barometer 243 
 
 Mowing Machine, Wood's 158 
 
 " " Kirby's 159 
 
 " " Buckeye 159 
 
 " " Cayuga Chief.... 160 
 
 Mowing Machines, Construction of.158 
 
 " " How to select... 164 
 
 Myers' Horse-fork 177 
 
 N 
 
 Norwegian Harrow 144 
 
 O 
 
 Ogle, inventor of the Finger-bar.... 159 
 Ox-yokes 78 
 
 P 
 
 Packer's Stone Lifter 62 
 
 Palmer's Horse-fork 176 
 
 ' ' Hay-stacking Machine 183 
 
 Paradox, Hydrostatic 203 
 
 Pile Engine or Driver 15 
 
 Pinions, Operation of 60 
 
 Pipes, To determine strength of 200 
 
 " Discharge of water through, 
 213, 2S4 
 
 Pitts 1 Straw-carrier and Thrasher. . . 190 
 Plank roads, Amount of resistance 
 
 on 84,86 
 
 Planting Machines 152 
 
 Plaster Sower, Seymour's 155 
 
 Platform Scales 52, 53 
 
 Plow, Kooloo 118 
 
 " Moorish , 118 
 
 " German 119 
 
 " Modern improved 119 
 
 " Moline Steel ...120 
 
 " Woodruff & Allen's 120 
 
 " Double Michigan 131 
 
 " Mole 139 
 
 " Ditching 138 
 
 " Side-hill or Swivel 132 
 
 " Subsoil 133, 135 
 
 ' l Trench 134 
 
 " Paring 137 
 
 " Gang 137 
 
 " Defects in 122 
 
 " Character of a good one 121 
 
 " Cutting edge of. 121 
 
 " Resistance of different parts. .122 
 
 " Form of the mouldboard 124 
 
 " Appendages to 140 
 
 " Wheel coulter and Weed-hook 
 
 on 140 
 
 Plowing, Operation of. 128 
 
 " Fast and slow 130 
 
 " Requisites for success in.. 129 
 
 Potato Planter, True's 156 
 
 " Digger 144 
 
 Power of a horse, Estimating 110 
 
 Press, Hydraulic 205 
 
 Presses for hay 184 
 
 Pressure of liquids, Determining. . . 202 
 
 " Upward, Measuring 199 
 
 " " in liquids 198 
 
 Pulley 61 
 
 Pulverizers 140 
 
 Pump, Cistern : 219 
 
 " Non-freezing 219 
 
 " Drive 220 
 
 " for deep wells 220 
 
 " Chain 221 
 
 11 Rotary 222 
 
 " Suction and Forcing 223 
 
 Pumping water by wind 248 
 
 Pumps, Construction of 218 
 
 Pyramids, Firmness of 38 
 
 Pyrometer, how made 26« 9 
 
INDEX. 
 
 301 
 
 R 
 
 Rake, Simple form of. 167 
 
 " Revolving 108 
 
 " " Warner's 10!) 
 
 " Spring-tooth 170 
 
 " " " Hollingsworth's.171 
 
 Ram, Hydraulic 226 
 
 Raymond's Hay Elevator 17S 
 
 Reaping Machines during the war. . 8 
 Self-rakers for.. 161 
 
 11 " Headers 163 
 
 " " How to select... 161 
 
 Revolving Hay Rake 168 
 
 Roads, importance of good ones.... 6S 
 
 " How to form the bed of 67 
 
 ** Measuring the friction on. . . 81 
 
 " Amount of resistance on 86 
 
 " Goodandbad 69 
 
 " Ascent in 63, 66 
 
 " Cost of going up and down 
 
 hill 65 
 
 Rocks, Machines for removing 62 
 
 Rockers, How to make 41 
 
 Rogers 152 
 
 Rolling Mill, Principle of 74 
 
 Root Washer 193 
 
 " Slicers 194 
 
 Rotary Spader, Comstock's 148, 117 
 
 " Pump 222 
 
 S 
 
 Sack-barrow, a lever 48 
 
 Sap, Ascent of. 33 
 
 Scotch or Square Harrow 143 
 
 Screw 70 
 
 " Archimedean 217 
 
 " Estimating power of.. 71 
 
 Seed Sower 153 
 
 " " Harrington's 157 
 
 Self-raking Reapers 161 
 
 Seymour's Broadcast Sower 154 
 
 Shares' Harrow 145 
 
 Side-hill or Swivel Plow 132 
 
 Single-tree, Wier's 98 
 
 Sowing Machines 152 
 
 Specific gravities, how determined. 208 
 
 " " Table of. 209 
 
 Springs of water 201 
 
 Stacks, Building by machinery 182 
 
 Steam engine, Construction of. 265, 267 
 " " for farm purposes..,. 270 
 
 Steel Plows... 120 
 
 Steelyard 47 
 
 Stone-lifter 62 
 
 Straw-cutters 16, 75 
 
 " carrier, Pitts' 190 
 
 Strength of materials 29 
 
 " " wood, iron, and ropes. 30 
 
 " " rods and bars 79,80 
 
 " " pipes, To determine... 200 
 
 Stubble Plow, Holbrook's 126 
 
 Stump-puller 54 
 
 Subsoil plowing 133 
 
 " Plows 135 
 
 Swivel Plow 132 
 
 Syphon 244 
 
 " used for draining 243 
 
 T 
 
 Teeth of wheels 58 
 
 Thill-cultivator, Alden's 146 
 
 Thrashing by machinery 187 
 
 " machine, Comparative 
 
 cheapness of. 188 
 
 Thrashing machine, Endless-chain 
 
 power for 188 
 
 Thrashing machine, Pitts' 190 
 
 Toggle-joint power 71 
 
 Tread horse-powers 1S8 
 
 " " " To determine 
 
 work of 188 
 
 Turbine Water-wheel 223 
 
 " " " Reynolds' 224 
 
 " " " Van de Wa- 
 ter's 224 
 
 U 
 
 Universal joint 60 
 
 Upward pressure of liquids 198 
 
 V 
 
 Vacuum, Machine running in 11 
 
 Velocity affects friction but slightly. 88 
 
 " of falling water 211 
 
 " of water in ditches .... 214, 286 
 
 " " through pipes 284 
 
 Ventilation 257 
 
 " through walls and gar- 
 rets 258 
 
 Ventilator, Griffith's 258 
 
 " Emerson's 255 
 
 Virtual velocities, Law or rule of. . . 43 
 
302 
 
 INDEX. 
 
 W 
 
 Wagon springs, Advantages of 17 
 
 " wheels, Proper width for. . .-. 87 
 
 Warner's Revolving Rake 169 
 
 Washing Machine 72 
 
 Water, Remarkable effects of heat 
 
 on 279 
 
 Water, Velocity of 211, 213 
 
 " Discharge of, through pipes. 212 
 
 " in ditches .„ 214 
 
 " wheels, Turbine. 223 
 
 " ram 226 
 
 " engines 230 
 
 Waves, Nature of. 232 
 
 " Velocity of 234 
 
 " Breadth and height of 233 
 
 4 ' To prevent inroads of . . 235, 236 
 
 Weather glass 243 
 
 Wedge 69 
 
 Weed hook on plows 140 
 
 Weighing machine, or platform 
 
 scales. 52, 53 
 
 Wheat drill 152 
 
 " " Bickford & Huffman's, 
 
 Construction of 153 
 
 Wheel and axle. . 55 
 
 " " " Modifications of ... . 57 
 
 Wheelbarrow, Operation of 47 
 
 Wheel-cutter to plows 140 
 
 Wheels, large ones run best 39 
 
 " for wagons Proper width 
 
 for 87 
 
 Whiffle-tree? for three horses 50, 97 
 
 Wind, Causes of 252 
 
 " Velocity of. . . . 246 
 
 " mill 247 
 
 " " Pumping water by 248 
 
 " "Brown's 251 
 
 Wooden legs, why hard to walk on. 40 
 
 Wood's Plow 119 
 
 Work of men and horses, Estima- 
 ting 110 
 
 3477