jmONTHLiY, FIVE DOLLARS PER YEAR. SINGLE NUMBERS, FIFTY CENTS. Ipliia in accordance with Section 19i» of the Postal Laws and Regulations ^ JOURJV4, OF the pRANKLiN Institute DEVOTED TO HSsSsiense and the Meahani® EDITED BY Dr. H. W. Jayne, Chairman, Mr. Edwin S. Baixh, Dr. Persifor Frazer, Mr. Louis E. Lew, Prof. Coleman Sellers, E.D., Committee on Publications ; with the Assistance of Dr. Wm. H. Wahl, Secretary of the Institute. VoL CLX, No. 4 80th YEAR OCTOBER, igos CONTENTS. Electrical Section : The Alternating Current Generator. David B. Ruslimore 253 Chemical Section : Mica and the Mica Industry. George Wetinore Colies, {to be continued) 275 ■^Sanitary Protection of Water Supplies. Kenneth Allen . . 297 Discussion : Dr. Henry Leffman 323 Notes and Comments ; The Value of Theory 251 German Shipbuilding in 1904 251 Reinforced Concrete Railway Ties 252 Smoke-Preventing Device 252 Allaying the Dust Nuisance on Highroads. . -274 Effect of High Temperature on the Strength of Steel 274 Healing Qualities of Egg Membrane 296 Preparation of Railway Cross-ties • • 296 The Disposition of the Boston “Franklin Fund” 296 Artificial Silk'. . 323 Book Notices : . , ' 325 The Franklin Institute: The Telautograph. H. L. English 241 Proceedings of the Stated Meeting held Wednesday, September 20, 1905 . 326 Committee on Science and the Arts 326 PUBLIS lED BY THE FRANKLIN INSTITUTE, Philadelphia. (B) Addres*! business correspondence, remittances, etc., to The ACTUARY ; editorial communi- cations to 1 HE Secretary. HouisoH 8t HOCUS Counsellors at Law SOLICITORS OF PATENTS PHILADELPHIA OFFICE REMOVED TO West End Building, 32 South Broad Street NEW YORK, 38 Park Row WASHINGTON, 918 F Street METALLOGRAPHY TAUGHT BY CORRESPONDENCE IN SEVENTEEN LESSONS I The Microstructure of Pure Metals II The Microstructure of Pure Iron III The Microstructure of Commercial Wrought Iron IV The Microstructure of Commercial Wrought Iron (Continued) V The Microstructure of Low-Carbon Steel VI The Microstructure of Medium High-Carbon Steel VII The Microstructure of High-Carbon Steel VIII The Influence of Carbonupon the Structure of Steel IX The Microstructure of Cast Iron X The Microstructure of Malleable Cast Iron XI The Thermal Critical Points of Steel XII The Thermal Critical Points of Steel (Continued) XIII The Thermal Critical Points ofSteel (Concluded) XIV The Structure of Steel Castings and the Influence of Hot and Cold Work upon the Structure of Steel XV The Influence of Heat and of Rate of Cooling upon the Structure of Steel XVI The Annealing of Steel XVII The Hardening and Tempering of Steel For farther p^^rHculars goStOH Tcstillg LabOfatieS ALBERT SAUVEUR, Hanager 446 Tremont Street BOSTON, HASS. Journal of the Franldin Institute — Advertisements. 1 CHEMICAL APPARATUS We carry in stock and have always ready for prompt shipment a ver)^ large and complete assort- ment of the best Chemical Glassware and general apparatus. We are now supplying many large laboratories, to which we shall be pleased to refer on request, and shall be pleased to send our catalogs to and correspond with others. Our line of CHEMICALS is drawn from the best manufacturers at home and abroad and is selected with special reference to analytical work. The fact that we supply many of the largest college laboratories vouches for its com- pleteness. Catalog on request. Estimd^tes Cheerfully Furnished. Bausch & Lomb Optical Co. Incorporated 1866 ROCHESTER, N. Y. NEW YORK CHICAGO BOSTON FRANKFORT a m, GERMANY 11 Journal of the Franklin Institute — Advertisements. INDEX TO ADVERTISERS PROFESSIONAL CARDS, PAGE XVIII Page American Gas Furnace Co v Association of Engineering So- cieties Journal x Barnett, G. & H. Co., File Works, Philadelphia, Fourth cover page Bausch & Lomb Optical Co i Borgner, Cyrus, Fire Bricks, etc., Philadelphia xi Boyden Premium, The, Frank- lin Institute viii Chester Steel Castings Co., Phil- adelphia V Harrisburg Foundry and Ma- chine Works, Engines, Third cover page Harrison Safety Boiler Works, Heaters Third cover page Hartford Steam Boiler Inspec- tion and Insurance Com- pany, Hartford, Conn xi Page Morse, Williams & Co., Eleva- tors, Phila. and New York.xiii Niles-Bement-Pond Co iv Olsen, Tinius & Co., Testing and Hydraulic Machinery., .xiii Penn Mutual v Phila. Commercial Museum, Third cover page Reeves, Paul S. & Son, Manga- nese Bronze xii Riehle Bros. Testing Machine Co XVIII Rue Manufacturing Co xiii Schutte & Koerting Co., En- gineers and Machinists, Phil- adelphia XI Scott Legacy Medal and Pre- mium, John, The Franklin Institute xx Sellers, Wm. & Co., Machinists, Philadelphia vi Howson & Howson, Patent So- licitors, Phila. and Washing- ton Second cover page Link-Belt Engineering Co., Ele- vators, etc X Living Age xiv Lonergan, J. E. & Co., Oilers, etc., Philadelphia xiii Southwark Foundry and Ma- chine Co V Spon & Chamberlain, Publish- ers, New York ix Standard Steel Works, R. R. Tires xvii Standard Typewriter Exchange. xvii Stern, Edward & Co., Inc., Print- ers, Philadelphia vii McCaffrey File Co., Fourth cover page Metallography. . .Second cover page Moore & White Co., The, Pa- per-Making Machinery xii Morris, I. P. Co., Machinery Back cover Tabor Mfg. Co., Molding Ma- chines xii Troemner, Henry, Scales xvii United Gas Improvement Co xv Weston, Chas. J., Scientific In- struments XIII Williams Typewriter xix Please mention this Journal in correspondence with advertisers. Journal of the Franklin Institute — Advertisements. Ill The Franklin Institute 15 South Seventh Street OFFICERS FOR 1905 PRESIDENT, JOHN BIRKINBINE VICE-PRESIDENTS, JAMES M. DODGE, HENRY HOVVSON, WASHINGTON JONES SECRETARY, WILLIAM H. WAHL TREASURER, SAMUEL SARTAIN ACTUARY, H. L. HEYL LIBRARIAN, ALFRED RIGLING CURATORS, WASHINGTON JONES, THOS. P. CONARD STANDING COMMITTEES OF THE INSTITUTE Library, LOUIS E LEVY, Chairman Science and the arts, E. GOLDSMITH, Chairman MEETINGS, WASHINGTON JONES, Chairman STANDING COMMITTEES OF THE BOARD INSTRUCTION, WILLIAM H. WAHL, Chairman Membership, ALEX. KRUMBHAAR, Chairman Stocks and finances, HORACE PETTIT, Chairman PUBLICATIONS, H. W. JAYNE, Chairman Exhibitions, HENRY HOWSON, Chairman Sections, JAMES CHRISTIE, Chairman Endowment, James M. dodge. Chairman MEETINGS Committee on Science and the arts, First Wednesday of each month, 8 P. M. (except July and August) . Board of managers, Second Wednesday of each month, 1.30 P. M. Institute, Third Wednesday of each month (except July and August) at 8 P. M. Section Meetings, Thursday Evenings of each week, 8 P. M. (excent July, August and September), "Commemorative Exercises of the Seventy-fifth Anniver*/'ary OF The Franklin In./'titute” has been published. It contain*/' an account of the proceedings, the addresses delivered with portraits of the speakers, and of Pre*/'idents of the Institute, and much matter of historic interest. NIL[S-B[M[NT-POND CO 136 Library St., New York, 1 1 Crane Works, Philadelphia iv Journal of the Franklin Institute — Advertisements. Bound in cloth; 272 pages; price $ 1 , 00 , Journal of the Franklin Institute — Advertisements. V Southwark Foundry & Machine Ca PHILADELPHIA, PA. SOLE BUILDERS OF THE ADAPTED JO EVERY CLASS OE SERVICE BLOWING ENGINES. WEISS CONDENSING PLANTS. The Fuel Gas System of the AMERICAN GAS FURNACE CO.” Includes Automatic Qas Generators Gas Blast Furnaces Automatic Heating Machines Positive Pressure Blowers, Etc., Etc. And every requisite for a thoroughly effective, Systematic and Economical Use of Heat in all kinds of work. Hundreds of first-class factories have it in use. Catalogues and pamphlets on application to AMERICAN OAS FURNACE CO., 23 John Street, New York City, STEEL CASTINGS OPEN HEARTH description, for Electrical Machinery ; Dredging Rolling and Sugar Mill Machinery , Eocomolive, Rail- road and Bridge Work, ete. Steel Castings of all shapes and sizes, from I lb. up. Superior for Crankshafts, Gearing and other pnrpo'^es where great wearing results are required. Correspondence Solicited. McHAFFlE Chester S.eel Castings Co. WORKS. CHESTER. PA. OFFICE, 407 SANSOM ST., PHILA., PA- Comfort in Old Age IS SECURED BY THE PENN MUTUAL LIFE INSURANCE COMPANY’S ENDOWMENT POLICIES Write for Booklet, stating your age PHILADELPHIA vi Journal of the Franklin Institute — Advertisements. PHlliADELiPHlA. PA. MODERN MACHINE TOOLS TOOL GRINDING MACHINES DRILL GRINDING MACHINES High-Speed Traveling Cranes Swing Cranes, etc. GORING AND TURNING MILL DRILLING AND BORING MACHINES IMPnOYED INJECTORS FOR BOILERS SHAFTS, HANGERS, COUPLINGS, PULLEYS, ETG., FOR TRANSMITTING POWER Journal of the Franklin Institute — Advertisements. vii WE GIVE SPECIAL ATTENTION TO THE PRINTING OF CHTBLOfiDES, PBICE-LlliTli B ClDLiIRS Our Designs are tasteful. Our prices are moderate. Our facilities for promptly filling all orders, whether large or small, are unsurpassed. Printing aiso in German, French, Spanish or Itaiian (Including Translation) Edward Stern & Co. (INCORPORATED) BOOK, NEWSPAPER AND JOB PRINTERS 1 12 and 1 14 NORTH TWELFTH STREET, PHILADELPHIA WORK OF THE HYDROGRAPHIC BRANCH OF THE UNITED STATES GEOLOGICAL SURVEY IN NEW ENGLAND and A DISCUSSION OF THE METHODS USED FOR ESTIMA- TING STREAH FLOW, H. K. Barrows. Boston Society of Civil Engineers. GRADE CROSSING PROBLEMS IN ST. LOUIS. WITH DIS- CUSSION. Carl Gayler. Engineers’ Club of St. Louis. FORCES DUE TO ECCENTRIC WEIGHTS ATTACHED TO ROLLING WHEELS. Calvin M. Woodward. Engineers’ Club of St. Louis. JOURNAL OF THE ASSOCIATION of ENGINEERING SOCIETIES 30 Cents per copy July, 1905 $3.00 per Annum FRED. BROOKS, Secretary 31 ^ilk Street BOSTON, HASS. Vlll Journal of the Franklin Institute — Advertisements. The Boyden Premium URIAH A. BOYDEN, ESQ., of Boston, Mass., has deposited with the FRANKI.IN Institute: the sum of one thousand dollars, to be awarded as a premium to “Any resident of North America who shall determine by experiment whether all rays of light, and other physical rays, are or are not trans- mitted with the same velocity.”* The following conditions have been established for the award of this Premium : 1. Any resident of North America, or of the West India Islands, may be a competitor for the Premium; the Southern boundary of Mexico being considered as the southern limit of North America. 2. Each competitor must transmit to the Secretary of the Franklix Institute a memoir, d escribing in detail the apparatus, the mode of experimenting, and the results ; and all memoirs received by him before the first day of January, one thousand nine hundred and six will, as soon as possible after this date, be transmitted to the Committee of Judges. 3. The Board of Managers of the Franklin Institute shall, before the first day of January, one thousand nine hundred and six, select three citizens of the United States of competent scientific ability, to whom the memoir shall be referred; and the said Judges shall examine the memoirs and report to the Franklin Institute whether, in their opinion any, and, if so, which of the memoirs is worthy of the Premium. And, on their report, the Fr.a.nklin Institute shall decide whether the Premium shall be awarded as recommended bj' the Judges. 4. Every memoir shall be anonymous, but shall containsome motto or sign by which it can be recognized and designated, and shall be accompanied bj' a sealed envelope, endorsed on the outside with some motto or sign, and containing the name and address of the author of the memoir. It shall be the duty of the Secretary of the Franklin Institute to keep these envelopes securely and unopened until the Judges shall have finished their examination ; when, should the Judges be of opinion that any one of the memoirs is worthy of the Premium, the corresponding envelope shall be opened, and the name of the author communicated to the Institute. The sealed envelopes accompanying unsuccessful memoirs, will be destroyed unopened, in the presence of the Board of Managers. 5. Should the Judges think proper, they may require the experiments described in any of the memoirs to be repeated in their presence. 6. The memoirs presented for the Premium shall become the property of the Franklin Institute, and shall be published as it may direct. The problem has been more specifically defined by the Board of Managers, as follows “ Whether or not all rays in the spectrum known at the time the offer was made, namely, March 23, 1859, and comprised between the lowest frequency known thermal rays in the infra-red, and the highest frequency known rays in the ultra-violet, which in the opinion of the Committee lie between the approximate frequencies of 2 x lo’ ^ double vibrations per second in the infra-red, and 8 x 10^ ^ in the ultra-violet, travel through free space with the same velocity,” JOURNAL OF THE Franklin Institute OF THK STATK OF PENNSYLVANIA FOR THE PROMOTION OF THE MECHANIC ARTS VoL. CLX, No. 4 8oth YEAR OCTOBER, 1905 The Franklin Institute is not responsible for the statements and opinions advanced by contributors to the Journal. FRANKLIN INSTITUTE. Stated Meeting, held Wednesday, MareJi 15, 1905. The Telautograph* By H. I. English. [This paper includes a brief account of the invention and development of the Graj" telauto- graph, and deals specially with the instrument in its present commercial form.— The Editor.] Electrical transmission of handwriting has engaged a certain amount of attention ever since telegraphic transmission or printed characters was successfully carried out. As early as 1886 Cowper and Robertson brought the writing telegraph into a fairly operative form. This instrument was adapted to operate several receivers in series in “reporting” service, where the regular news ticker service was unobtainable or too expensive. The system was put to some use, chiefly in Pittsburgh and vicinity. The writing was received on a paper tape, advanced at con- stant speed by clockwork. No pen-lifting device was provided VoE. CLX. No. 958. 16 242 IJ.F.I., English: and the woials were connected tog'ether l)y a mark of the j^en, making- hgnrework poor. As the characters were formed l)y the coml)ination of the ])en motion and the ta})e motion, a cer- tain amoimt of ])ractice and skill was required to ])roduce a legi- ble message. The electrical features were as follows: Two indei)endent va- riable currents were obtained from the transmitter ;these passed over lines to the receiver where they traversed two electromag- nets set at right angles to each other, and so influenced their ef- fect upon a common armature as to cause the receiver-])en rod to ])roduce the motion of the transmitter pencil. It will be noted that this ])rinciple is nearly identical with that of Gruhn’s Telechirograph, recently described in the tech- nical press, the main differences being that the telechirograph writes upon a larger field and uses a beam of light, and photo- gra])hic record instead of a pen with ink record. Following the writing telegraph. Professor Elisha Gray con- structed. at his Chicago laboratory, an instrument which wrote upon stationary paper, and which he called a telautograph. It recjuired four line wares and operated as follow-s : By means of cords and drums the motions of the transmitting stylus were resolved into tw-o mechanical interrupters in the primary cir- cuits of tw^o induction coils. The relations of the parts were such that a motion of the transmitting stylus amounting to one-fortieth of an inch caused a complete make-and-break at one or both of the interrupters. The line currents w^ere the impulses produced in the secon- dary circuits of the induction coils. These impulses passed over lines to tw^o electromechanical escapements in the re- ceiver. By means of cords and drums their motions were com- bined and caused to act upon the receiver pen. By the use of relays and condensers and a local battery at each receiver the ])a])er w-as advanced when necessary and the pen lifted from and low^ered to the paper. The mechanical difficulties met w-ith in perfecting' this instrument w'ere very great, and in the apparatus exhibited at the A\Trld's Fair, in Chicago, in 1893, the escapement mechanism w^as brought to a perfection thought impossible of attainment only a short time before. The w-riting show'ed a saw'-tooth or step-by-step character, due to the action of the escapements. The instrument w'as aband- October, 1905. J 243 The Telautograph. oned on account of the number of line wires required, limited speed, numerous fine adjustments, and cost and difficulty of manufacture. In 1893, while still working at the escapement device. Pro- fessor Gray patented a variable-current instrument, using two line wires, which worked, in a general way, like the present telautograph. The motions of the transmitter pencil were re- solved into two components which were used to vary two line currents, the variable resistances being carbon rods dipped into tubes of mercury. The receiver contained two D'Arsonval movements, to the moving elements of which the pen-arms were attached. Professor Gray never developed this instru- ment much beyond the laboratory stage, probably on account of his firm belief in the escapement type. Foster Ritchie, at that time an assistant to Professor Gray, gave considerable attention to this patent and perfected an instrument based on it. He obtained a patent for improve- ments and has produced an instrument that operates in a fairly satisfactory manner under certain favorable conditions. The telautograph has been brought to its present state chiehy through experimental work done by, or under the per- sonal direction of Mr. George S. Tiffany, to w'hom several pat- ents for improvements have been granted. Mr. Tiffany’s in- strument operates on the variable-current principle and in- cludes a number of interesting features, among them what may he called a straight-line D'Arsonval movement, which is used to operate the receiver. The operation may be briefly described thus : At the trans- mitter a pencil is attached by rods to two lever-arms which carrv contact-rollers at their ends. These rollers bear against the surface of two current-carrying rheostats, connected to a constant-pressure source of direct current. The writing cur- rents pass from the rheostats to the rollers and from them to the line wires. When the pencil is moved, as in writing, the positions of the rollers upon the rheostats are changed and currents of varying strength go out upon the line wires. At the receiver these currents pass through two vertically movable coils, suspended by springs in magnetic fields, and the coils move up or down according to the strength of the line surrents. The motions of the coi^^ are communicated to levers similar to [J. F. L, ^244 English: those at the transmitter, and on these levers is mounted the receiver pen, which, l)y the motion of the coils, is caused to du- plicate the motions of the sending pencil. Many of the principles and devices in the instruments are of considerable interest. The method by which the variable cur- rents are obtained is the laboratory arrangement for securing a variable pressure from a direct current, constant pressure cir- cuit; that is, the line circuit (of constant resistance) is con- nected as a shunt around that part of the rheostat between the moving roller and the ground or return. ^Motion of the roller varies the amount of resistance in series with the line and also the amount in parallel with it and fine graduations are easily obtained, giving smooth motion of the receiver pen. In this way a variable pressure is impressed on the line circuit, giving a variable current. In all the other variable-current instru- ments, a constant pressure was impressed on line and a resist- ance in series with the line varied to give the desired variations in current. One result of the shunting method is a better form of rheostat, more easy of construction and handling, in which, also, the heating is better distributed. The rheostats are wound upon castings of I cross-section, with the turns of wire lying close together on the inner or con- tact-face. After winding, the insulation on this face is sat- urated with glue, which is allowed to harden and is then scraped off, taking the insulation with it, and giving a surface where contact is possible on every turn of the wire. This gives a rheostat of a large number of small steps, of good mechanical construction, and of low cost. The receiver operates with what may be called a straight-line D'Arsonval movement. The moving element or coil is wound upon a copper shell for damping effect. The magnetic cir- cuit is so arranged that one pole surrounds the other, forming an annular air-gap of short length and large cross-section in which the direction of the flux is radial. The field is electro- magnetic and is highly excited, to secure uniformity. The coil suspended in the annular space, moves up or down with little friction, as it touches the sides of the space of the core very lightly, if at all. The principle is the well-known one that a circuit-carrying coil, in a magnetic field, tends to place itself October, 1905.] Tlic Telautograph. 245 with respect to the held so that the flux enclosed by the coil shall be a maximum. The current for operating is taken from the ordinary lighting mains, preferably at about 115 volts. Satisfactory operation has resulted with pressures from 80 up to 250. At 115 volts, receiver and transmitter each require about one ampere while in operation. Fairly steady pressure is necessary as the re- ceiver, being in effect a voltmeter, is rather sensitive to sudden changes, the effect being slight distortion of the message. A master-switch at the transmitter is provided to do all nec- essary switching of line and power circuits, to make needed changes in connections and to cut off current when not writing. A relay in one of the lines closes the power circuit of the re- ceiver whenever the transmitter at the distant station is switched on, and serves to prevent waste of current when not in operation. Attached to the master-switch is a mechanical device which shifts the transmitter paper the space of one line of ordinary writing for each stroke of the switch. The relay mentioned controls the electrical receiver paper shifter and, as each stroke of the switch causes a stroke of the relay, the receiver paper is shifted an amount equal to that at the transmitter. The writ- ing is about two inches long and five inches wide, allowing for three or four lines of writing. When filled by messages a few strokes of the switch serve to bring fresh paper into position at both receiver and transmitter. To prevent switching on of the transmitter while its home receiver is receiving a message from the distant station, an electromagnetic lock is connected in the receiver power circuit, controlled by the relay, and locks the home transmitter in the “off” position until the distant transmitter is switched off. If both transmitters were switched on at once neither station would receive any message; the lock is provided to render this condition impossible. The ink supply is most important and is arranged for as fol- lows : At the left of the receiver platen is a bottle with a hole in the front near the bottom. When filled with ink and tightly corked the ink does not run out of this hole because of the pressure of the atmosphere. The ink is accessible for the pen 246 [J.F.I., English: at the hole and the surface of ink ex])osed to e\'aporation is small. The pen is made of a ])iece of (derman silver bent double, after the manner of a ruling pen, and makes a uniform line in any direction over the paper. It takes up its supply by capil- lary attraction, from the hole in the front of the bottle. When the receiver is switched off, retractile springs draw the i)en- arms to stops so arranged as to bring the pen exactly in front of the hole in the bottle, and when the ])en-lifter armature is released the pen is caused to insert its ti]) in the opening. Thus a fresh fflling of ink is obtained each time the paper is shifted. W'hen not in use the pen rests in the ink, always ready to write. For the prevention of mechanical shocks to the necessarily ligdit moving system of the receiver, it has been necessary to supply means to prevent the switching on or off of the trans- mitter, and by that action of the receiver, when the transmitter ])encil is ‘‘out in the field;” that is, at a position other than that corresponding to the opening in the receiver ink-bottle ; as in that case the receiver pen would instantly jump to a similar position. This position is called the “unison point," a term having its origin in the days of the “self-propellor" escapement telautograph. By placing a catch, released only by pressure of the pencil-point upon it, at the transmitter unison point the desired result is accomplished and the transmitter master- switch cannot be switched either “off" or “on" unless the pen- cil be placed at the unison point and held there until the stroke of the switch is completed. In this case, as everywhere, the apparatus is made strong enough to stand any possible shocks, and then every precaution is taken to prevent their occurrence. Aside from shock to the moving system, these jumps might shake the ink supply out of the pen and prevent the recording of the message. The pen-lifter is a magnet ])laced back of the receiver writing ])laten, and carrying upon its armature a rod adapted to engage with the pen-arm rods and raise the pen clear of the paper when the magnet is energized. This magnet is controlled from the transmitter as follows: Beneath the transmitter platen is a spring contact, opened bv pressure of the pencil upon the ])aper, and closed by a spring when the pencil is raised. An in- duction coil having an interrupter iu its primary circuit is so October, 1905. J 247 The Telautograph. connected to this spring-contact that when the pencil is raised the primary winding is short circuited. The induction coil has two independent secondary windings through which the two variable line currents pass before leaving the transmitter. The effect of the induction coil and its interrupted primary current is to induce in the two-line current superimposed vibrations or “ripples” when the pencil is pressed down on the paper and the spring-contact is open. When the contact is closed, by its spring, and the primary winding is cut out, no vibrations are produced in the line currents. In one of the line wires, at the receiver, is placed a relay, upon whose sheet-iron diaphragm armature is mounted a loose contact, consisting of two plati- num-silver contacts in series, sealed in a glass tube, to prevent oxidation. A local circuit contains the winding of the pen- lifter magnet and this loose contact. When the vibrations are present in the line current, due to the pressure of the pencil upon the paper and consequent opening of short circuit of the primary of the induction coil, the diaphragm of the relay is shaken, the loose contact opened and the pen-lifter de-energized, its armature is drawn back by a spring and the pen is allowed to rest against the paper. When there are no vibrations in the line currents due to the raising of the pencil from the paper, the relay diaphragm is at rest and the pen-lifter is energized and the pen is lifted clear of the paper. The superimposed vibrations used for operating the pen- lifter have another minor effect. The suspended coils, and through them the entire moving system of the receiver, are kept in a state of very slight mechanical vibration while the pen is on the paper. This aids the flow of ink from the pen-point, assists the pen in passing over any roughness or irregularity in the surface of the paper, and materially reduces friction in the joints and pivots of the moving system, and results in better writing. In some of the later instruments the two relays, that for pen-lifting and that for paper-shifting and power switching, are combined in a single piece of apparatus. For signalling, a push-button is placed upon the transmitter and a call-bell or buzzer is mounted on the receiver. This cir- cuit is disconnected by the master-switch while a message is be- ing written. Spring reels are attached when needed to roll 248 [J. F. I., English: up the received messages for preservation and future reference. The ordinary arrangements for operation are as follows : The instruments may be operated singly, upon a private line having an instrument at each end, or on an exchange system where a switchboard provides for connection. Working in this way, satisfactory writing has been obtained with a resistance in each line wire of 1600 ohms and an operating pressure of no. Multiple operation can be carried out to a limited extent, three receivers being at present the maximum number that can be operated at once, in multiple, using no volts. This allows of placing a supervisory machine upon a line. Instances in actual commercial use of the arrangements of instruments in Philadelphia are: Provident Life and Trust Co., Corn Exchange National Bank, West End Trust, Tradesmen's Trust Co., Girard Trust Co., who use the Telautograph to con- nect from paying teller to book-keeper to ascertain a deposi- tor’s balance. C. J. WTbb & Co., 116 Chestnut Street, have a line which connects to their warehouse, 148 X. Eront Street, for giving orders for shipment of wool. Philadelphia Electric Co. have a line to connect from loth and Sansom to Second and Arch Streets; this line is used mainly for sending the read- ings of meters to the book-keeping department. Strawbridge & Clothier use the instrument to connect from the Superintendent’s office to the Auditing Department, for as- certaining a customer’s credit. Einley Acker Co. have lines October, 1905.] 249 The Telautograph. which connect their three stores, Twelfth and Chestnut, Twelfth and Market and 128 N. Eighth Street, to their book-keeping department, to ascertain the reliability of a customer's credit. Multiple operation may be resorted to when a third station upon a line desires a record accessible at any time, of what is being sent, as for instance, when one of the officers of a bank desires to know what passes between his book-keepers and paying tellers. On such a line the third station receives all messages and can write to either or both of the other stations should the necessity arise. Such an installation can be seen at the North American Trust Co., New York. Series operations may be used when several stations are to receive the same message and no response except a bell signal is required, as in sending orders in a hotel or club from dining room to kitchen, pantry, or wine room; in “reporting” or news service, or for bulletin work, such as the announcement of ar- rival and departure of trains to a number of stations in a large railway station or freight depot. Recently two such installations, one at the St. Louis Term- inal, St. Louis, Mo., the other at the Pittsburgh Terminal of the Pennsylvania Railroad Company, at Pittsburgh, Pa., have been made, and a similar installation at Broad Street Station is plan- ned in the near future. One of the most important uses for series systems has been found in the U. S. Coast Defense .Service, in sending ballistic data, such as range and azimuth of target, or character of pro- jectile, from position-finding stations to the gunners. This is called “fire-control communication,” and is installed in the forts of the U. S. Signal Corps. In a paper presented by Col. Samuel Reber on “Electricity in the Signal Corps,” will be found a description of the position-finding system and the de- sired characteristics of a system of communication for sending this data to the guns are stated as follows: “The system that will successfully solve this problem must be simple in construc- tion, mechanically strong so as not to be affected by the blast, as the receivers are placed close to the guns, rapid in operation, and give a character of record that can be read without liability of error.” Since that paper was prepared it has been decided that the receivers must be mounted directly on the gun-car- riage and can have no shelter other than that afforded by their 250 LJ. F. [., English: own cases. Add to these recjuirements the facts that the in- struments must he cared for l)y ])ost electricians, and operated by enlisted artillerymen, messages must he visible at night ; and the operation must he independent of rain, salt mists, cold, heat, or tropical insects, and it is apparent that no easy ])roh- lem is presented. A special type of telautograph has been designed for this service, and has been adopted l)y the U. S. Signal Corps for fire-control communication. In this ‘‘service telautograph” the pen-lifter controlling the relay is eliminated and the receiver pen-lifters are operated over a third line wire by the transmitter platen switch directly. Each gun receiver is enclosed in a water-tight brass case, sus- pended by springs from the gun carriage directly in front of the g'unner. The parts are, as far as possible, made “brutally strong,” and the construction is as simple as possible. The desired rapidity of operation is inherent to the telauto- graph, and accuracy of record is ensured by careful writing and by the use of a “home” receiver, mounted at the transmitter, where the operator can see plainly, which is connected in series with the gun receivers and records the messages as actually sent over the line. Freezing of ink is prevented by the addition of alcohol; and rain, mists, and insects, as well as the effects of the blast, are shut out by the metal case. A heavy glass window is placed in the case so that messages can be read without opening the case. A small incandescent lamp inside the case lights automati- cally when the receiver is writing and may be lighted by press- ing a button at other times, thus providing for visibility at night. On warships there is a somewhat similar service to be ren- dered and the performance of this should fall to the army type of telautograph. Commercial service has given opportunity for the installa- tion of a considerable number of private, line telautographs in actual use, and at least three of each of the other typical in- stallations are in operation at the present time. Much of the improvement in details of construction and re- liability in operation has resulted from experience gained in October, 1905.] Notes and Coninicnts. 251 efforts to perfect service of these commercial plants. The ex- perience leading up to the special arm type of telautograph has extended over a period of about five years, and in the present instrument all the requirements, unusually severe as they are, have been successfully fulfilled. THE VALUE OF THEORY. That the electron hypothesis is weakening faith in some of onr most cherished theories of electrical action cannot be denied; and the time-hon- ored tenets of magnetism are now subject to challenge as a consequence of the researches in non-ferric alloys by Fleming and Hadfield, In view of this condition, which may be disturbing to the minds of those who do not properly recognize the real function of theory, it is well to remember that established theory should never be held as an article of faith — as is too often done when connected with names of high authority — but considered only as an acceptable generalization on all the facts in existence coming within the range of the theory. To hold any theory as an ultimate explanation of any set of phenomena implies that every fact relating to the phenomena is known — that nature has nothing more to reveal. It is, more- over, a condition of the growth of human knowledge in any department of science, that whereas the advance never ceases in the acquisition of facts, yet the interpretation placed upon series of facts may vary markedly from time to time. The wealth of acquired material does not shrink, but always advances, sometimes rapidly and at other times more slowly. Nevertheless, the theories embracing the facts, and attempting to explain them, often wax and wither in a single decade. It might really be questioned whether in view of the history of mortality in theories it were worth while attempt- ing to find a theory to fit observation, and whether it would not be better to go on accumulating new materials of facts, heedless of their theoretical relations. The value of theory is, however, that it co-ordinates, or at least seeks to co-ordinate, the facts so as to permit of their proper grouping and presentation in natural sequence. Without the aid of theory, knowledge would constantly become more difficult, by accumulation; whereas, with the aid of theory, knowledge may actually grow easier to acciuire, from age to age, in spite of the constant accumulation of material . — Electrical World. GERMAN SHIPBUILDING IN 1904. One of the most important lines of Germany’s industrial expansion has been in shipbuilding. Figures transmitted by United States Consul-General Richard Guenther, Frankfort, Germany, show that in 1904 the German shipyards turned out 278 steamships of 210,999 gross registered tons and 256 sailing vessels of 49,712 gross registered tons. At the beginning of 1905 they had under construction 152 steam vessels of 285,539 gross tons, of which 9 were men-of-war of a total of 69,640 tons. The production for 1904 includes 22 steamers and some sailing vessels, of about 20,000 tons in all, built for foreign account. 252 Azotes and Comments. [J. F. L, REINFORCED CONCRETE RAILWAY TIES. An interesting use of cement is a method of manufacturing railroad ties recently introduced on the Elgin, Joliet & Eastern Railway. These ties are manufactured under a design originated by R. B. Campbell, general mana- ger of the company, Joliet, 111 . The tie is 8 feet 6 inches long and 6x7 inches in section, with beveled edges, except under the rails, where it widens to 10 inches for a distance of SV2 inches on either side of the center of the rail. The corners of this widened portion are also beveled to meet the body of the tie. Reinforce- ment is furnished by two-inch wrought-iron pipe, scran boiler tubes being utilized for the purpose. Two-seven-foot lengths of these tubes are used for each tie, placed side by side. The tubes are surrounded, sides and ends, by a single thickness of poultry netting. On the center line of the tie be- low each rail, and parallel thereto, is a 6x8 inch plate of heavy wire netting inserted through specially-punched openings in the pipes. The rail is held to thel tie by beveled clip washers and a single U-bolt placed obliquely to the longitudinal center line. A metal plate is imbedded in the tie under the rail. Very satisfactory tests were made with a number of these ties on a testing machine, and 140 were placed in use, which have been in service from nine to thirteen months. Of these ties nineteen failed in service, but investigation showed that the defects were caused through imperfect mix- ture, there having been considerable loam mixed with the sand in making the concrete. The results, however, were regarded as sufficiently satis- factory to warrant the manufacture of icoo more of the ties, which are to be placed in the track of the Chicago, Lake Shore & Eastern Railroad, where the traffic is very heavy. Mr. Campbell states that the ties can be manu- factured and sold at a cost of $1.50 to $1.75 each. — Iron Age. SMOKE-PREVENTING DEVICE. A new smoke-preventing device for boiler furnaces has been invented by Air. J. S. Pearson, of Glasgow. The system consists of discharging a com- bination of steam, air and producer gas into the furnace. The three ele- ments are combined and discharged through nozzles fitted to short pipe connections. The resulting chemical action releases the hydrogen in the steam, and combines the oxygen with the carbon in the fuel. The decom- nosition of the supplied gases is thus completed, and. by combining with the fuel gases and the resulting new gases thus produced, creates great heating power, emitting heavy smoke. The latter, however, decreases in volume toward the tubes, in which there are only fiames, and is completely con- sumed before it reaches the chimney. The steam pressure does not vary with the stoking or cleaning of the furnace, and no ashes or clinkers are formed. The system can be applied to any type of boiler. — Scioitific American. October, 1905.] Alternating Current Generator. 253 ELKCTRICAI^ SECTION. (Stated Meeting, held Thursday, March yo, ipoy.) The Alternating Current Generator, By David B. Rushmore. [This article is suhstautially a historical sketch of the origin, development and present status of this important class of electric generators.— The Editor.] The dynamo dates from the discovery by Faraday, in 1831, of the law of electro magnetic induction. The previous discov- eries of Oersted, in 1820, regarding the relative positions of a permanent magnet and an electric current, and of Arago and Sturgeon of the possibility of making magnets from pieces of soft iron by passing an electric current around them, led Fara- day, in an unparalleled series of experiments, to discover that important law, and on September 4th, of that year, was first coined the expression “lines of force.” Faraday's disc generator, constructed in 1831, was an experi- mental unipolar and is of interest as being the first dynamo electric machine. The early development of the dynamo con- sisted of many modifications of magneto generators, and it was aliout 1856 that the first commercial use was made of such ap- paratus, when the embryo of our present arc lamp was supplied by current from a machine built by the Campagnie de TAlli- ance, which had been developed by VanMalderen and Nollet. This installation was in the lighthouse. Until 1876 there was a large amount of work done in the development of dynamo machines, most of which were, however, for the generation of •direct current and concerned with the work in which are asso- ciated the familiar names of Siemens, Wheatstone, Pacinotti, Wilde, Gramme, Lontin, de Meritens, Brush, Weston, Edison, Hefner- Altenech, Ganz and Schuckert. What might justly be called the first practical alternators were those built by Gramme, between 1876 and 1880. These are 254 Rush more: IJ.F I.. interniil revolving;- field c^enerators with direct-connected ex- citers, and were demanded l)y the desire to have l)oth carbons of the Jal)lochkoff candles l)nrn evenly, which could not be done with the direct current machines then in use. The armature winding- is stationary and external, but is the same as the ])reviously well-known Gramme ring construction. The arm- ature is wound with four sei)arate phases and the earlier ma- chines have eight j^oles on the field and eight sections on the armature. The corres])onding coils in the different sections were connected in parallel or series, as was desirable. It was with these machines that the term “exciter” was first used. The special interest of these machines to-day is the fact that they were of the internal revolving field type with a ])olyphase armature winding* and having direct connected exciters. Following the Gramme machines we have a development of alternators by de Meritens, Hefner-Alteneck, Ganz, Schuckert, Zipernow^ski & Deri, and, in more recent years, such machines as designed by Kapp, Mordey and Ferrenti. The first machine used to any extent in this country was de- veloped about 1886-7. It consisted of a stationary external field with inwardly projecting pole pieces, the cast-iron pole pieces and yoke being cast together. The pole face was beveled slightly at the armature surface, but was. not extended beyond the pole core. The internal revolving armature consisted of discs built up directly on the shaft. There were six ventilating holes running lengthwise on the shaft but none at right angles thereto. Wooden pieces w*ere secured to the ends over which the flat pancake coils were wound, the ends being bent back at right angles from the cylindrical surface. AToden pieces were also placed in the center of the flat pancake coils, and later the same were placed between the adjacent coils. The core was covered with insulating material on which these wooden strips were fastened, being held by screws, which passed through the insulation into the iron core. After the coils were wound by hand on the surface of these machines, another cov- ering of insulation was placed aroinul the armature, which was held in place by bands of piano wire, and on the ends by end bells. These machines possessed excellent regulating c|uali- ties, good wave form, and good alfility to radiate heat. They were, however, very easily injured, and the entire winding October, 1905.] 255 AUcniating Current Generator. could be stripped from the armature by a piece of metal falling thereon or by the wear of the bearings, allowing the armature to strike the pole pieces. These early machines were all for 15,000 or 16,000 alterna- tions and were, of course, single phase. The pulsating arma- ture reaction from these alternators caused the pole pieces to heat, and the first change was to cast laminated poles into the field yoke. The next change was to make a toothed armature with one tooth per pole and one armature coil per tooth. These armature coils were machine wound and were insulated sepa- rately from the core. They were drawn beneath the project- ing top of the teeth and were held in place by a wooden wedge driven between the adjacent coils. Brass shields fitted over the projecting ends of these coils, completly protecting them from the possibility of external injury. These iron-clad arma- tures were a great improvement mechanically, and it was pos- sible to subject them to very rough handling without injury. The concentrated winding gave poor regulation, a bad wave form and poorer heating qualities than the smooth core type. The considerable pulsation of magnetic reluctance caused heat- ing. The quickness and ease of repair, however, made these machines a decided improvement over the old ones. There were a considerable number of modifications of both the smooth core and toothed machine with regard to com- pounding. In some cases an auxiliary winding was placed on the armature and the current therefrom taken through a two- part commutator to either the main or auxiliary field. In other cases, the main current passed through a series trans- former, either consisting of the arms of the machine itself or a separate transformer external to the armature. From the toothed form, a polyphase machine was developed known as the Plus 2 type, in which the revolving armature had two teeth more than were poles on the field. Taps led into the armature at points 90° apart and gave the desired quarter-phase relation of the current. The next step was to distribute the winding- in many small slots, as is now done. This allowed the use of machine-wound coils, which were easily placed on the arma- ture, and were held in place by wedges passing over the slot. With this winding, better regulation and better wave form were obtained, as well as improved ventilating qualities. The sup- 256 Riislunore: [J. F. L, porting arms of these armatures were used for series transform- ers and by means of a two-part commutator, the machines were compounded. Radial ventilating ducts were also introduced, and about this time the use of oil rings instead of the oil drip became general. The revolving armature with a distributed winding was built in many sizes and with a considerable varia- tion of mechanical construction. The demand for higher voltages led to the practice of build- ing the armature external to the field and revolving the field. This allowed the armature circuit to remain unbroken, the only sliding contacts being those for the low voltage field ex- citation with carbon brushes on cast-iron rings. It also al- lowed the armatures to be wound directly for voltages as high as 13,200. The field coil is made of copper strip wound on edge, making a large saving in the amount of material neces- sary for this part, and so making the field coil practically inde- structable by heat. Simultaneously with these improvements, a great change has taken place in the insulation used for arma- tures and the use of oil in some form having become the best practice. NIAGARA FALLS GENERATORS. The recent development of alternator design is well shown in the different types of machines which have been furnished the various power stations at Niagara Falls. These machines have been so frequently described that only the points of particular interest will be touched upon. The original design consisted of the umbrella type external revolving field supported from the top of the shaft. This gave the advantages of combining the fly-wheel with the revolving field and with having the centrifugal force of the poles in oppo- site direction to the magnetic pull. It also relieved the bolts holding the poles of any strains due to centrifugal force. The revolving field ring was forged from an ingot of compressed nickel steel without a weld, and the poles were solid steel cast- ings held to the rim by bolts. The field coils were held in place by the projecting tips of the pole. A rectangular wire was used in the field coil, which was wound up in solid form and was not ventilated. The collector was placed on the upper end of the shaft and a bridge structure ran over the machine in October, 1905.] 257 Alternating Current Generator. order to give access to the collector and bearings. The arma- ture slots were nearly enclosed with two conductors per slot and insulated with material, which was largely mica. The bolts clamping the armature iron passed through the laminations which were ventilated with six one-inch ducts. The ends of the armature winding were left unsupported. On these ma- chines thrust bearings were used as the direction of the press- ure on the vertical shaft varied with the load. The second lot of machines were made by the same manufac- turers as the first, but a number of changes were introduced which experience had shown to be desirable. The nuts on the field ring were sunk into the metal. The field coil was very much changed, being wound with a number of layers of copper strip wound on edge, and the whole being well ventilated with ducts through the winding and holes cored into the bobbin. The field coil insulation was largely mica and shellac. In the armature twelve half-inch ventilating spaces were used instead of six one-inch, as in the first machine. The bolts clamping the iron did not pass through the laminations and much better work was done on the punchings, so that less finishing of the slots by filing was required and in this way the heating consid- erably reduced. The slots were made more numerous and smaller, so that there was l3ut one conductor per slot and the armature winding was reduced 15 per cent. AVith this reduc- tion came also a reduction in length of, air gap from one inch to three-quarters of an inch. Like the first machine, the second had also very bad regulation, which was at that time considered advisable as giving the small cross currents and also as placing an automatic limit to the current output of the machine. The ventilation of the first machine had not taken place as expected and drag hoods were placed on the revolving part of the second machine. The armature was also cooled by means of circulat- ing water in heavy copper tanks placed back of the laminations. The third machines were built by a different manufacturer, and were considerably changed in design. The purchasing com- pany, however, demanded that in general appearance and ar- rangement that they conform to the previous types. The collec- tor rings were placed below the armature and the bridge over the machine was omitted. The regulation was made very much better than in the old machines. The armature coils were ma- Vor. CIvX. No. 958 17 258 Rushmore: [J. F. I., chine wound and consisted of rectangular cable placed in open slots with two coils per slot. The poles, instead of being solid, were laminated and the load losses thus materially reduced. The method of ventilating was also entirely changed, so that the air was drawn into the center of the machine from below and forced out at holes in the upper part of the revolving ring. The fourth type of Niagara machine was made by the same manufacturer as the third but the type of machine was entirely changed. In this generator, the internal revolving field was used and while this choice was due to the development which had taken place in this style of machine it was allowable in par- ticular because of the improvements made in water wheel gov- ernors, which necessitated a smaller fly-wheel capacity. Nu- merous ventilating ducts were placed in the armature. The slots were open and contained two conductors of standard cop- per cable. The ring of the revolving field is built up of laminated steel sheets and the poles are built up separately of the same material. These are then held in place in the field ring by dove-tails and keys. The armature coils are supported on the ends outside of the laminated iron to prevent any bind- ing effects due to short circuits or heavy currents. In other respects, the generators are all standard revolving field type of construction. The fifth Niagara machines are double the output of the previous ones, or 7,500 K.W. each. The mechanical structure of the armature frame differs somewhat from the previous ma- chine, but in general the variation is simply one of size. In this machine the solid bar is used for the conductor in the bot- tom of the slot and a stranded cable, which is passed through the vacuum japan treatment, for the conductor at the surface. In this country modern types of alternators are divided into two distinct classes, the inductor type and the revolving field type. The revolving armature with external field is still used to some extent. Descriptions will be given of the inductor type alternator as developed and manufactured by the Stanley Elec. Mfg. Co., and of revolving field generators made by the same concern, illustrating the engine type and coupled or water-wheel type. Also, a brief description of modern forms of turbo-alternators. Prankiin insi., VoL CLX, October, igd^. {Xushmore) k 4 I" S. K. C. inductor alternator, engine type, 300 KW.— 182 R.P. M. 8000 alts. Winding on aiinature not shown. Details of slot, field bobbin, inductor punching, and hub. 26 o Riislujwrc: [J. F. I., the conditions. A consideralde variation in mechanical con- struction exists in each type. The armature frame may either be made of cast-steel shell or tie-bar construction, depending upon the size of the machine and the output per pole. \Miere kilowatts per pole exceed a certain figure, a limited peripheral velocity may necessitate the use of a cast-steel shell. In the standard tie bar construction, the external stationary armature Fig. 2. Xo. 1(! machine. .S4:i. C'oil clamps and connections. INDUCTOR ALTERNATOR. The inductor alternator was developed in this country about twelve years ago, and was at that time decidedly superior to any other machine on the market. The mechanical construc- tion is clearly illustrated in Figs, i, 2, 3 and 4. These machines are made either engine type, coupled or belted, depending upon washer which fixes the distance between these rings. The out- side rings in some cases have the shields to protect the arma- ture coils cast in one piece with the ring. In other cases the shields are separate and are fastened by screws. It is seen that the space between the two center rings is but partially occupied by the magnet bars and that a large amount of space, affording easy egress for the air circulated by the revolving inductor is offered, thus giving excellent opportunities for ventilation of field coils and inner ends of the armature winding. The laminated iron in these machines consists of the best obtain- October, 1905.] Alternating Current Generator. 261 is supported by four cast-iron rings which are parted in either an horizontal or vertical plane. The armature laminations are held between the bars on outside rings and are supported on tie bars which connect the cast-iron rings as shown, while sup- porting the active iron, and, also, act as part of the magnetic cir- cuit of the armature, although the magnetism of these bars un- dergoes no variation. Half of the bars butt against the out- side rings, as shown. Between the two metal rings is a pipe Fig. 3. S. K. C. inductor alternator showing method of removing armature coil. 262 Rush more: [J. F. I., able quality of sheet steel, made according' to rigid specifica- tions, which is afterwards punched out at the shop and thor- oughly annealed and japanned by special processes, the de- velopment of which is the result of many years of experience. On the ends of each section of laminated iron are sheets of much heavier rolled plate, called stiffeners. These keep the laminated sheets in shape and ])revent their spreading apart. Fit?. S. K. V. Indicator Alternator Coinjilete. The inductor alternator has but a single field coil and this is supported on the inside of the armature structure and does not revolve. The coil consists in the larger machines of a flat cop- per strip wound inside a brass bobbin, the sections of winding being separated from each other by a wide ventilating duct passing radially through the center of the coil. The strips are insulated from each other by means of oil cloth and the whole winding is insulated from the bobbin hy means of specially pre- October, 1905.] 263 Alternating Current Generator. pared insulating material. The winding of the field coil is thus seen to be well protected from any possible mechanical injury and to be exposed to excellent ventilation on the sides of the coil and also through the center by a current of air set up by the skeleton revolving mass known as the inductor. The arm- ature winding is placed in slots in the laminated iron and is held by either clamps on the ends of the coil, as in some of the old machines, or by wooden wedges across the top of the slot in the latest types. The armature winding is in almost all cases what is known as the concentrated winding. This gives a firm coil with very short ends, needing no support on the ends of the coils to prevent a bending effect from short circuits. In the larger machines, the armature coils can be removed without disturbing the machine in any way. It is usual to wind the armature with two coils per slot, although certain cases arise in which the one coil per slot arrangement is necessary. The entire armature winding is accessible for inspection when the machine is not in operation and in a way not possible with any other type of machine. The armature winding consists of either wire, strip or stranded cable wound on suitable forms and properly insulated. Where stranded copper cable is used and in all other cases where it is advisable, the winding is given 264 RusJimorc: [J. F. I., a vacuum compound treatment which completely fills the in- terstices of the coil with an insulating japan. This is then pressed into shape and baked so that a uniform solid structure results which cannot be injured by vibration, and which is prac- tically indestructible under such conditions of operation as should exist. These machines may be wound for one, two or three phases, and in the latter case the winding may be for either a star or delta connection. In the insulation of the arm- ature coils, the best and most recent type of oil cloth insulation is -used, no micanite being permitted in any part of the coil. Such oil insulation if not subjected to too great a temperature remains for years in practically the same condition as when first placed on the coils. The revolving part, known as the in- ductor, consists of a skeleton steel casting on which are mounted pole and projections of laminated steel. The ex- ternal magnetic part of this structure is mounted upon arms and held in the usual manner, and the castings are sub-divided in a variety of ways as best suited to the particular machine as regards the convenience of handling. The central part of the revolving casting is cored out at intervals around the circum- ference giving one-third of the space in ventilating holes and about two-thirds of solid metal, which arrangement affords the best possible ventilation for the field coil, allowing a blast of air to be thrown against the three sides and forced through the center ventilating space. The rims on which are mounted the pole laminations are cut away between the polar projections in October, 1905.] Alternating Current Generator. 265 the later machines. This style of construction, known as the skeleton inductor, allows the armature coils to be easily re- moved from the larger machines, affords the best possible ven- tilation and considerably improves the electrical characteristics of the machine with regard to exciting power and regulation, the actual leakage in this type of machine being reduced to approximately 5 per cent. The pole is so formed as to give a magnetic field varying as a sine function of the angle from the center of the pole, which, with the concentrated winding, gives a sine wave of E.M.F. This is an important feature of the in- ductor alternator and is very difficult to obtain in the revolving field types except with distributed windings. The peculiar electrical operation of this machine is that the flux through the armature pulsates through the armature coils and swings through a certain angle with respect to the armature iron. This allows the use of high densities in the laminated iron with- out causing heating of the same. Thq regulation of the inductor alternator can, of course, be made anything desirable, and, in comparing this type of ma- chine with that of the revolving field alternator, any slight dif- ference in weights may not necessarily mean a similar differ- ence in cost. In comparison with revolving field machines, the inductor alternator possessing the same efficiency will have a higher armature copper loss and a lower iron and field copper loss. This accounts for high efficiencies at light loads and the fact that the iron in the inductor alternator armature heats but little prevents local rise of temperature in the armature coils. The characteristic points of this type of machine are as fol- lows : No revolving wire; no sliding contacts; a single field coil ; the field coil entirely protected from mechanical injury ; the possibility, in larger sizes, of removing the armature coil without disturbing the machine ; the small exciting power nec- essary; the sine wave of E.M.F. with concentrated winding; the proportionately short length of idle conductor in the arma- ture ; the unequaled ventilation of armature winding ; the ab- sence of any necessity for supporting the armature coils at the end, and, in general, the machine demanding the minimum of care and attention. 266 Rushnwrc: IJ. F. L, REVOLVING FIELD ALTERNATORS. A tyi)ical modern revolving field alternator is shown in Fig. 5. The active material of the external stationary armature is supported by a cast-iron box frame. Armature frames are made in a large variety of styles and sections abroad, but in this country the section shown may be taken as standard. The frame may be divided either horizontally or vertically, and in some of the larger machines is divided into a greater number of parts to facilitate shipment and erection. The box form used gives the best utilization of the material and affords an easy means for ventilating the armature laminations. These laminations are held by dovetails cut into ribs cast on the armature frame, which ribs run parallel with the shaft of the machine. There are also numerous methods for supporting the laminations but this method of dovetail suspension is the most substantial and best. The laminations are divided lengthwise of the machine by many ventilating ducts which allow the free passage of air from the revolving field and are held together by retainers at each end, clamped by bolts pass- ing entirely back of the laminations. This laminated iron is punched, annealed and japanned in the same way as previously described, and its proper manufacture is one requiring great knovdedge and skill to obtain the best results. The armature coils are machine-wound and are completely Most revolving field alternators have a distributed winding giving two or more slots per phase and by proper beveling of the pole a sine wave of E.M.F. is obtained. The greater the sub-division of the winding, the better the wave form, and the better the opportunities for dissipation of heat. The proportionally large amount of space occupied by insula- tion in high voltage machines limits the possibilities of winding distribution from both mechanical and commercial considera- tions. Open slots allow the coils to be machine wound and be subjected to vacuum compound treatment and completely in- Fig. 8. Upper half of ar.natare frame without enh shields sho ving method of supporting end connections. October, 1905.] Alternating Current Generator. insulated before being placed in the open slots. The use of open slots is of great advantage in machines wound for high voltages, as it allows the complete insulation of the coil before it is placed on the machine, and with the oil cloth insulation used where the oil is brushed on each wrapping of cloth and separately baked, the insulation of the entire coil consists of a large number of coatings of an oil film, each complete in itself. Stationary armatures allow the electrical circuit to be un- broken, which is of great advantage in high voltage machines. 268 Riishmorc: [J.F.I., siilated l^efore being placed in the machine. W'ith cal^le con- ductors this is almost a necessity in order to o1)tain firm coils and to properly insulate the strands. Hig'h voltage machines necessitate good insulation between the conductors in a coil, as well as between the conductors and iron, a matter not always sufficiently emphasized. By com- pletely insulating the coil before placing it in the slot, this may be accomplished, and in high voltage machines, especially those used as synchronous motors, it is a very important factor. Fig. 10. Stationary armatures for turbine-generators. Open slots in general necessitate laminated pole pieces, which are, however, of advantage both from a standpoint of symmetrical construction and in preventing an increase of iron loss under load, even though there may be no Focault losses in a solid pole piece on open circuit. Laminated poles allow a quicker response in voltage to any change of excitation. Poles are fastened to revolving field rings in a large variety of ways. Where the poles are separate from the ring, they are usually held by bolts which enter keys running lengthwise October, 1905.] Alternating Current Generator. 269 through the laminated poles in machines of comparatively low peripheral speed, and where the speed is high the laminated pole is dove-tailed and keyed into the ring. The development of the revolving field alternator brought with it the edge wound copper strip field coils, one of the great advantages of this type of machine, and the manufacture of which illustrates a high development of machine-shop practice. This strip-wound field coil is of excellent mechanical structure, which cannot get out of shape and which is in very little danger of injury from over-heating*, the external surface of the coil being entirely exposed to the air, it being impossible for any local rise of temperature to take place. The proximity of the field coil to the armature surface acts as a damping device and is in most cases sufficient preventive against hunting troubles. Fig. 9. Revolving Held showing details of mechanical construction, illustrating careful considera- tion of stresses due to centrifugal force. 270 Ritshmorc: [J. F. L, Solid field rings are in this country universally made of steel and made cast in one piece with the arms and hub, or the latter may be made of cast-iron 1)olted to the field ring. The ventilation of the revolving field alternator is somewhat inferior to that of the inductor, and to overcome this a number of methods of construction are used. One of these consists in casting holes in the field ring between the poles and by suitable end rings and cross-webs which act as fans. Fig. 6. Engine-driven revolving field alternators of large output. Fig. 11. Kevolving field for a 5000 KW. alternating current turbine generator. especially for the higher frequencies, are often of such dimen- sions that the revolving field and fly-wheel can \'ery suitably be combined. In such cases the fly-wheel is usually built up of steel plates. WATER WHEEL GENERATORS. The use of heads ranging from 1,500 to 2,300 ft., and the demand for units of large output, in many cases K.W., October, 1905.] Alternating Current Generator. 271 has led to the development of a water-wheel type of generator, machines and the standard revolving held generators is princi- Such generators must be built to stand an increase of speed of Fig. 12. 5000 KW. Curtis steam turbine direct connected to 5000 KW. three-phase alternating current generator. something less than 100 per cent., and for this reason the me- chanical design takes precedence over the electrical. The difficulty of hauling these machines for distances up to forty miles to inaccessible power house locations and over bad Jour. Franklin Inst., Vol. CLX, October, 1903. {Rnshmore) :i. .■)()(»• K' .W .( 'iirt IS 1 iirhiiic H(‘l w itli iiuxiliarics. October, 1905.] 273 Alternating Current Generator. roads often influences the mechanical design. An illustration of a machine designed for such conditions is shown in Figs. Nos. 7, 8, 9. This machine was built by the Stanley Elec- tric Mfg. Co. for the California Gas and Electric Corporation, and is a 5,000 K.W. three-phase revolving field generator, run- ning at 400 revolutions and giving 2,400 volts, which voltage is raised by transformers to 60,000. The stationary armature is a more or less standard construc- tion, except that the weight is reduced to a minimum and the' details of every part are most carefully designed in order to make the structure as light as is consistent with necessary strength. The revolving field is of novel construction. The ring and poles are built up of laminated steel sheets, each punching covering two poles and the section between them. In one punching the pole part on one end extends to the air gap; on the other to the bottom of the pole tip. These punch- ings, thick, are built up in pairs. In this way the resultant structure gives a solid pole while the space between the poles consists of alternate spaces of air gap and the same amount of laminated iron. The field coils are cemented into one solid structure and each individual coil, as well as every separate part of the revolving field, is carefully weighed and balanced. The revolving field ring, built up of laminations, is mounted on the hub by steel end plates, as shown, and is divided into two parts to facilitate transportation by the insertion of two plates in the center, which are similar to the end plates, except for the con- nection to the hub. After the field coils are placed on the pole, the tips, which are inserted between the alternate laminations, are then put in place and bolts running lengthwise through these tips and the alternate projecting pole pieces, passing also through retainers over the ends of the field coils and holding same in place. TURBO-ALTERNATORS. ^ In turbo-alternators, the considerations of the mechanical design are of first importance, and the difference between these machines and the standard revolving field generators is princi- pally one of comparative output and speed, and of methods and devices for supporting the structure under the necessarily great mechanical strains. Vor. CLX. No. 958 18 274 Notes and Comments. [J. F. I., Laminated steel is a material of known strength which can be relied upon, and, therefore, is largely used in the construc- tion of the revolving field for turbo alternators. The central ring is built up of these steel sheets and so arranged that the poles are built up and riveted separately, and introduced end- wise into the ring structure through proper dovetails and are held firmly in place by keys. The unbalanced component of centrifugal force at right angles to the side of the field coil is taken into consideration by placing proper wedges between adjacent coils. Straps passing over the coil ends securely hold these parts in place. Other types of turbo alternator construc- tion are used, but that shown in Figs. lo, ii, 12, 13, may be taken as representative of the vertical type used in this country in connection with the Curtis turbine. ALLAYING THE DUST NUISANCE ON HIGHROADS. For some time past experiments have been carried out in England with several media such as westrumite, and so forth, for overcoming the dust nuisance on the high roads, which is created more especially by automo- biles. These materials, however, have proven only partially successful. The results of some later experiments in this direction which have been carried out in Liverpool were recently described by Mr. A. Lyle Rathbone. deputy- chairman of the Liverpool Health Committee m a lecture at Liveipool. The surface of a selected roadway was coated with creosote oil mixed with resin. This mixture gave the cleanest and nicest appearance, while the sur- face coated with ordinarv petroleum was the least lasting. Next in order came mixtures of creosote oil with tallow, and hot creosote oil. Heavy coal tar waste oil lasted rather longer than the creosote oil, and was very much cheaper. Considering the experiments as a whole, the result would seem to point to eventual success with the use of some classes of oil in tne place of water on macadam roads . — Scienfitic American. EFFECT OF HIGH TEMPERATURE ON THE STRENGTH OF STEEL. Professor Bach has made some experiments to determine the effects of high temperature on the strength of steel, using groups of four bars each. The temperature of the testing of the several groups were: Atmospheric, 390, 570, 750, 930 and 1020 degrees F. On one bar the test at ordinary tem- perature showed a strength of 54,000 pounds per square inch and an elonga- tion of 26,3 per cent. The strength appeared to increase with rise of tem- perature, until at 750 deg. the figure stood at 60,300 pounds, while above this temperature the strength decreased rapidly until at 1020 degrees it was only 26,000 pounds per square inch. October, 1905.] Mica and the Mica Industry. 275 CHEMICAL SECTION *Mica and the Mica Industry. By George Wetmore CoLLES.f [The subject is treated in eight principal captions: Mineralogy, geology, geographical distribu tion, history, mining, uses, statistics and conclusions. Tne treatment is industrial rather than theoretical or scientific, and aims at setting forth the present, past and probable future of mica- mining in this and other countries. The first instalment dealt with the characteristics of the various species of mica. The present part deals with the geology of the micas,— Thk Editor.] IL GEOLOGY. Micas of the perissad class (as above indicated), are found in or derived from igneous, that is to say, intrusive or meta- morphic rocks. They are the commonest of minerals, common in the sense of being widely distributed, though constituting but a relatively small proportion of the rocks in which they occur. These micas constitute the most conspicuous element in granites, and in most schists and gneisses, as well as in that form of intrusive rock known as pegmatite. The artiad micas, on the contrary, do not occur (unless possi- bly in minute crystals of the ferrous kinds) in igneous rocks, but are found associated principally with crystalline lime and magnesian rocks, such as calcite and pyroxene. The origin of these two classes will therefore be considered independently. In addition to these sources of mica, it is a very common constituent of many fragmental rocks, ordinary quartz-sand, etc. Whenever a mica-bearing rock is eroded by water, parti- cles of the mica which it contains are carried with it and depos- ited in beds somewhere in the course of the stream. Al- though mica is a heavy mineral (sp. gr. 2.6 to 3.2) its flaky nature causes it to be carried along or floated with an equal facility to lighter materials, such as sand, and when deposited with the latter in large quantities, the flakes falling naturally into a horizontal position, and the strata being afterwards con- solidated, a schistose rock is formed, which easily splits by rea- son of the lack of cohesion between the mica plates. *Read by title, f Copyright, 1905, by George Wetmore Colies. 276 Colies: [J. F. I., THE GRANITIC MICAS. Such is doubtless the origin of most micaceous schists; but there are other rocks of a similar class and quality, which are to be classed rather as metamorphic, that is to say, rocks of a sedi- mentary or fragmental origin, but which, when deposited, con- tained no mica, and in which the mica has been developed by a process of slow crystallization under the continued application of heat. We pass thus gradually from the fragmental schists to gneiss, and go still further on the same lines from gneiss to granite, in which the bedding of the material has been entirely lost ; and finally from granite to pegmatite, which latter may be described roughly as a kind of gigantic granite — a rock formed of the same materials but in very much larger crystals.* Now, granite is a rock composed of three principal constitu- ents, namely, mica, feldspar and quartz, and these minerals, as such, are not necessarily present in the rocks from which they have been formed. Their common occurrence, and more par- ticularly that of mica, in rocks which have been altered by heat from rocks which did not contain them, is an evidence that, given the materials — alumina, potash, silica and water — and the necessary conditions, these materials will come together and crystallize out into mica of their own accord. That this is what happens, when a rock of sedimentary origin is altered to gneiss, is readily shown to be the case by the examination of a region of local metamorphism ; that is, by examining the nature of the ground adjacent to a dike of igneous rock, for example, when what has been changed to gneiss close to the dike is, on following it back, found to pass gradually into sandstone, etc., the mica and other crystals making their appearance increas- ingly as we approach the dike. Proceeding a step further from gneiss to granite, we have rock which results from a still further heating of the gneiss to at least a plastic condition, in which the materials have so rear- ranged themselves that the bedding is completely lost. The heat has been sufficiently continued and evenly maintained to permit the materials to group themselves into larger crystals. *There are several differences between granite and pegmatite besides the mere size of the crystals, that point to a difference in kind as well as one of degree. One of these is the different character of the mica crystals. October, 1905.] Mica and the Mica Industry- 277 It is a well-understood principle that the size of the crystals formed increases with the slowness of the action, and this prin- ciple is clearly illustrated throughout the igneous rocks, and as- sists us in explaining the manner of their formation. The same rock, for instance, in a volcanic vent, which will on the surface form a close-grained, amorphous or aphanitic lava, will be found to pass downwardly into a more crystalline form until we reach the condition of granite. The pegmatic dikes in which the commercial mica occurs are, as before stated, composed of the same three body-miner- als as in granite; but the crystals are often enormous, weigh- ing several thousand pounds. The mica in these dikes is al- ways in the form of more or less perfect crystals, called by miners blocks or ‘‘books.” The feldspar is also more or less perfectly crystallized, but much of it is massive, and the bulk of the quartz is also massive. It is deserving of note, further, that while quartz veins* are of common occurrence, and while dikes of feldspar and quartz occur together without the mica — in fact about as frequently as with it — the mica itself, which constitutes the least bulk of the vein, is never found without both the feldspar and quartz. It is also important to note in this place that the mica crystals as taken from the dike, are of rough, opaque and irregular ex- terior, and have rounded ends and angles. The outermost plates, and the edges of all the plates, are valueless, and have obviously either (i) suffered alteration from their original form, or (2) never quite reached the constitution of mica, strictly speaking. With these preliminary considerations we are in: position to consider, first the age of the dikes, and afterward the origin of the mica. Age and Origin of the Pegmatite Dikes. The mica-bearing dikes in New Hampshire, North Carolina, South Dakota and India, and probably in all other places where *The net-work of coarse and fine quartz veins which commonly traverse the dikes and country rocks are merely an aqueous filling of cracks formed by the folding and faulting of the rocks, and must not be confounded with dikes of igneous origin. 278 Colies: [J. F. L, mica has been mined, occur in rocks of the Archaean age, the first age known to geological history. The rocks of this age are not, however, either wholly or mainly igneous, but, like those of subsequent ages, are principally bedded or seni- mentary rocks, which were once deposited at the bottom of a body of water. All, or nearly all, the rocks of the Archaean series, so far as known, have undergone metamorphic action, and become more or less crystallized. Into and through these rocks, which themselves contain mica in large quantities, but in minute scales, have been injected the dikes in question and take the form of sheets more or less continuous and irregular, cutting across or between the strata which they intersect. Now, it does not fol- low, because these are found in Archaean rocks, that they have been formed in Archaean time, as it is clear that, if no reasons to the contrary exist, they might have been formed at any subsequent epoch ; but I believe that such reasons do exist, and that they show quite clearly that these dikes were formed shortly after the formation of the rocks themselves, at least in the case of the North Carolina series, to which the following remarks have application more particularly, although I believe in a general way they will apply to other regions where mica dikes are found. These dikes, generally speaking, follow the strike and dip of the country rock ; that is to say, are interposed rather between the layers than across them, though frequently breaking from one to another, besides branching out and becoming divided, and being of very irregular width. A single outcrop may ex- tend several hundred feet on the surface of the ground, and may be as much as 50 to 100 feet in width (still wider ones have been found), or may have any dimensions less than these. The outcrop being “nipped” at any point (that is, tapering down to nothing), may begin again a little further on or at one side of the point of nipping. (See Fig. 20.) The distribution of the mica in the vein is not uniform, nor is it entirely irregular. It has a tendency to gather into bunches, or in strings of crystals. It may be found ranged along either or both walls of the dike, or bunched in the recesses thereof, or in branches and pockets of the dike, or again, packed in bunches in the center at inter- vals. Fig. 17 illustrates some of these peculiarities. October, 1905.] Mica and the Mica Industry • 279 The influence of the wall rock on the material of the enclosed dike is often distinctly noticeable. Mica-bearing dikes predominate especially where they interpenetrate schists and micaceous gneisses ; but not necessarily so, as good mica-bearing dikes also penetrate strata containing little mica. In India, how- Fig. 17. Section of Point Fizzle evcr, tliis peculiarity secuis to bc very (Cioudland) mine, a, dike; ^ mica. (After Kerr.) StrOUgly brOUgllt OUt, aild SO inucll SO that one writer on the subject assumes it as a proof of the aqueous rather than the igneous origin of the dikes.* The boundaries of the dikes are usually well defined and in close contact with the wall-rock, though a clay selvage has been ob- served at the juncture. This is undoubtedly formed by the decomposition of the dike-material through the action of water in the usual manner of feldspar. Fragments of wall rock are occasionally found in the dike, and Figure 18 is an example of a horse of wall rock running parallel to the dike, the only example known in North Carolina of this structure. Fig. 18. Section in Silvers Mine (after Kerr). a, country rock; J), horse of same; c, dike mate- rial; cl, quartz vein; e, mica. In considering the origin of these dikes it seems to have been generally assumed that the dike-material was projected up- wards while they lay in their present position. I cannot see any reason for adopting this view, while, on the contrary, there appear to me to be strong reasons for believing them to have been formed while the rocks were horizontally bedded. More- over, with a few possible exceptions, there is nothing to show *A, Mervyn Smith in “Mica Mining in Bengal, India.” Trans. Inst. Min. and Met., Vol. vii, p. 170. This theory is referred to later, (See discussion on p. 282 et seq. 28 o Colies: []. F. L, that the fissures, in which they lie, were ducts which led the ^material in a stream from some heated source below to the sur- iface;but,on the contrary, they are distinctly of a laccolithic char- acter; in other words, they were the mere filling of cracks which extended laterally from the source of molten material, probably ramifying from this source and ending in a cul de sac. Figures 19 and 20 represent graphically the general manner in which the dikes may be supposed to have been formed. A Figure 19 shows a vertical cross-section of a part of the bedded rocks and a column of fluid or semi-fluid rock-material injected upward into them by pressure from below, and naturally raising the strata above it. The rocks are supposed to be deeply bur- ied under overlying strata, and the heat to increase down- wardly until at their lower portion they become sufflciently fluid to be forced upwardly in the manner indicated, raising the overlying rocks. For the force to accomplish such an injection, we would only need to look as far as the difference in specific gravity between the solid and fused material, and the expan- sion of the water contained in the latter — I will not say steam, as is done by some writers, for it is clear that steam could hardly — at any rate did not — exist under this pressure and the comparatively low temperature which must be assumed. Whether the fissures were made by the pressure of the material which filled them or by some other agency, or by both acting to- October, 1905.] Mica and the Mica Industry ^ 281 gether, is a question which need not here be answered. After the material filled the fissures an excessively slow cooling rate is demanded by the condition of the dikes, as we find them, by reason of the immense size of the crystals. Supposing, then, dikes to have been thus formed and cooled, and subsequently the rocks to have been tilted through an angle a. Fig. 19, and ■erosion taken place until the surface of the ground lies on the plane AB, the appearance of said surface would then be as shown in Fig. 20, which represents the dikes as we actually find them. The reasons for the conclusions above adopted are as fol- lows : (i) The country rock shows a regional and not merely local metamorphism, as it would if it had been near the surface Avhen the dikes were intruded, and such metamorphism were caused by the heat of the dike-material itself. In other words, the metamorphism of the rocks is comparatively uniform throughout the entire area under consideration. Such meta- morphism implies that the rocks must have been buried very deeply in the earth, at least several miles below the surface. Now, that there has been an enormous denudation of the Archaean rocks, — greater, perhaps, than that of any subse- quent series, — is clear when we consider that the rocks of all subsequent formations have been made from them. We must suppose, then, that the existing rocks were formerly overlaid by a thickness of several miles of the same system, and it is very improbable that much folding could have taken place before these subsequent rocks were laid down, or yet while they were very deeply buried, because we know that much folding has taken place since then, which, of course, tends to tilt the rocks always more steeply and never to return them to their horizon- tal position. The same holds good even if the strata overlying them were of a later age, for example, the Silurian or Carbon- iferous.* 2. The material of the dikes had no outlet to the surface, as it would, have had if the rocks had been tilted (because the pressure would have been exerted to split a passage open in- stead of to raise the rocks) ; because (a) we find no deposits of material which would indicate such outflow ; (b) the vein would have been banded, which it is not, or crystallized normal to the 282 Colles: [J. F. I., surface, indicating a cooling from the exterior inwardly, which it is not ; and (c) because the continued or interrupted flow through the fissure would have prevented the formation of any large crystals. With a few possible exceptions, like that illus- trated in Fig. i8, the dikes are of a simple structure, that is to say, show that like conditions existed throughout, and no bands nor orientation of the crystals (unless it be that of the mica crystals inter se) can be observed. 3. To permit the slow rate of cooling demanded by the large- sized crystals and the other conditions just specified, the coun- try rock must have been raised to a temperature approximating, if not equal, to that of the fused material, thus constituting a mass perhaps several miles thick, which would require centuries to cool down to the condition of complete solidification. This of itself indicates horizontal strata for the reason above indicated, viz., that the metamorphism took place before the tilting of the strata. The aqueous theory of these dikes deserves mention here as it has been seriously put forward by at least one writer. The reasons given for this theory are as follows : (i) “in many places the veins die out in depth and in length;” (2) “the vein matter partakes of the quality of the including rock, — quartz, feldspar, and mica predominating, as the lode traverses rocks containing these minerals in excess;” (3) “the crystallization of the vein matter varies within very short distances, not being at all homo- geneous as one would expect in an igneous dike. In places the crystals of mica are two feet long, eighteen inches wide and nine *From a consideration of the positions of the strata, J. D. Dana con- cludes that “no upturning took place over the Appalachian ^Mountains south- east (sic) of New England until the Carboniferous Age was approaching, or had reached its end.” A like conclusion is reached by J. A. Holmes, who has shown that the pegmatite dikes intersect the Archaean of Arizona, where it is cut through by the Colorado River in the Grand Canyon, coming up to the base of the Algonkian (the series next following the Archaean), which overlies these rocks, and consequently that the dikes were formed before the Algonkian period. In this case, however, the tilting of the rocks must have taken place during the Archaean itself, and consequently the intrusion of the dikes at a period long preceding even that comparative!}" early epoch. October, 1905.] Mica and the Mica Industry. 283 inches thick. Within a few hundred feet on either side of this spot the mica books are small and worthless.”* Not only are the reasons so given to support this theory quite inadequate and inconclusive, but the theory is open to other objections which appear to me quite insuperable. Ap- parently it is based on the assumption of open fissures formed in the rock, into which ground waters carrying dissolved con- stituents of the country rock have flowed and evaporated, thus leaving behind the dissolved matter as a crystalline residue. To answer first the three reasons supposed to support the theory : (i) The fact that the veins die out in depth and length does not necessarily imply this theory more than another, as we have seen. (2) The influence of the substances of the wall-rocks can be explained equally well on the igneous theory ; in fact such influence is commonly felt in igneous dikes. It is frequent for the materials of intrusive and intruded rocks to become interchanged through metamorphism, — not, however, that this has been the case here. Such influence is readily explained, more particularly where the wall rock is a fi'able mica schist or the like, on the assumption that the fissure produced by the Assuring forces was not a clean one, but that much of the rock- material was pulverized and mingled with the vein-material and subsequently dissolved therein and recrystallized. Besides, sup- posing the vein material to be merely melted wall-material from further down, it would naturally have a similar constitution. (3) That the constitution of an igneous magma should be not strictly homogeneous, but should vary within distances of a few hundred feet, is really no stranger than that an aqueous solu- tion should do the same thing. The most obvious objection to the aqueous theory is, that it presupposes fissures or voids in the rock which could hardly have existed. Either (i) such fissures must be formed while the rocks are still horizontal, or (2) after the rocks had been tilted, in which case they must have extended from the surface downward. The first assumption, in view of the great weight of overlying rock, is obviously untenable. The second is almost if not quite equally as untenable, by reason of the lateral press- ure on the earth’s crust which would close the fissures. Such *A. Mervyn Smith, loc. cit. 284 Colles: [J. F. I., fissures are indeed formed in the course of mountain-making upheavals l;ut they are of a temporary nature, and are quickly filled with debris from the surface, which could not fail to show in the vein. Besides, as we have seen, the dikes have, in many cases at least, been formed before the rocks were tilted. I con- sider this reason alone conclusive against the aqueous theory. Further, however, it may be said that (i) the constituents of such veins, if formed, would be banded and would show a crys- tallization normal to the surface, and this as we have seen really never happens; (2) the water would evaporate too quickly to produce large crystals ; (3) the mica portion of the vein-constituents is insoluble in water, and in fact in any other liquid, at surface temperatures and pressures. To suppose them to have dissolved out of the rocks and recrystallized by the action of water, is no more reasonable than to suppose that the mica had been conveyed there bodily. This fact also ap- pears to me conclusive against the aqueous theory. In fact, the crystallization of mica, in the present state of our knowl- edge, implies the presence of heat. Origin of the Mica. Having thus determined the age and manner of formation of the dikes, it remains to consider how the mica was formed and reached its present position. Three views have been pro- posed: (i) that the mica crystals were formed in the fused rock-mass before the latter was injected into the fissures to form dikes; (2) that the mica existed separately as such in the fused mass at the time of intrusion, having been formed further down ; and (3) that the mica, quartz and feldspar all existed to- gether in a homogeneous solution both before and after the in- trusion of the dike material, and that the several materials crys- tallized out one after the other in the same manner, as for ex- ample, salt crystallizes out as a result of mixing soda and hydro- chloric acid ; the several materials being brought together by chemical attraction in either case. That the third theory, or rather a modification of it, is the only rational one of the three can, I think, be readily shown to be the case. First, however, we must consider which of the three princi- pal materials of the dike reached the solid condition first. Under conditions as we know them in the laboratory, the feld- October, 1905.] Mica and the Mica Industry- 285 spar has about the lowest and quartz the highest melting point of the three, the mica occupying an intermediate though some- what variable position; but under conditions of high pressure and temperature, and added to these the elements of water, these conditions may be widely different. That water must have been present is to be taken for granted, both because it is diffi- cult to assume a high enough temperature to have produced the effects without it, and also because it is present in the mica ; as well as from the fact that steam is always given off in vol- canic action. The mica and feldspar are in fact both crystallized in a mas- sive quartz matrix. The mica plates have left their marks both on the feldspar and on the quartz. It is clear that the mica could not have crystallized after the other two had solidified around it, therefore it is tolerably clear that the mica crystal- lized first, or at least concomitantly with the feldspar. We may assume that the feldspar and quartz together formed a ve- hicle for the mica. The crystalline form of the feldspar would seem to indicate that it separated out from the magma after the mica, leaving the quartz behind to solidify last. If the quartz still contained water (which would have made it more soluble) this has been subsequently driven off. If the mica had been carried up in solid crystals mixed with the magma, we should here find it (i) all arranged on the hang- ing wall, to which it would have floated as soon as the magma came to rest, supposing it to have been lighter than the latter ; or (2) it would have sunk to the bottom and we should And it all on the foot-wall of the dike, had it been heavier than the magma. Furthermore, it is utterly impossible that small branches of the dike could have been found packed full of mica crystals ; in short, this theory is obviously untenable. That mica may have existed as such in solution in the magma may well be admitted, but the question as to whether it existed in any special combination apart from the other elements, is about as futile as a like question with regard to all chemical solution. Suffice it to say that the arrangement of the crystals does not admit of any general theory, which does not presup- pose that all the elements of the dike were uniformly mixed and tolerably homogeneous at the time they entered the Ass- ures in which they cooled. Formed as they were from rocks 286 Colles: []. F. I., containing the same materials, and, indeed, the same minerals only in different form, they could not have recrystallized in larger crystals had they not been dissolved and recombined. It has been shown that wherever the materials of mica are present in such a mixture, even though it be not fully fluid, they tend to be drawn together and to crystallize out as mica. The fact that chemical affinity exists sufficient to segregate them, even in a sulDstantiall}^ solid rock, is shown by com- mon local metamorphism, and is rather strikingly illustrated by the parallel case of crystallization or recrystallization of hard steel under long-continued vibration. In this case it requires a jarring movement to bring the molecules together; in the case where they are held in a partially or wholly melted state, for a sufficient length of time, chemical attraction alone seems necessary. The force that will explain the building up of a large mica crystal by the drawing together to one point of the elements of such a solution, seems absolutely identical with that causing a crystallization of any chemical substance from solution, more particularly if it be assumed that as the solution cools the mica becomes more and more insoluble therein. That, moreover, the mica did so crystallize is plainly indi- cated by its local position in the dike, from its having, as afore- said, a tendency to cling to one wall or to the other, or to cling together in aggregates precisely as in the case of other crystal- lization from solution, and the same reasoning pursued will ex- plain equally the separation of the feldspar and quartz in great masses instead of in small particles as in other rocks. Much has been said and somewhat has been written on a pos- sible rule for finding the mica, and although miners themselves pretend to have rules and principles for finding it, it is pretty safe to state that no such rule exists, and that ’aside from the principle of crystallization which is alluded to, mica crystallized at random on one wall or the other, according to where chance happened to start the process. It was stated above that the dike material in the fused form was substantially homogeneous, but of course this does not necessarily apply to very exten- sive areas, and from place to place it would naturally vary in its contents of mica materials, thus g'iving rise to barren spots in the dike, and in some cases to dikes which were altogether free from mica ; but the causes and order of such events would be as October, 1905,] Mica and the Mica Industry- 287 difficult to define or regulate by rule as the movements of old Mother Earth herself. The question as to what causes the rough, scaly exterior of mica crystals is one of considerable interest, and no doubt hav- ing an important bearing on the question of origin, but one which, so far as I know, has never been discussed. That it is not a result of secondary alteration or at any rate of the action of air and water penetrating from the surface, is, I think, all but certain. It has been shown that ordinary watering processes have little effect on ordinary muscovite, and if weathering were the cause, the effect would be limitd to mica dikes which have been partially disintegrated by weathering, and not extend into the solid rock itself. Moreover, there is no indication in the incasing matrix of any such alteration. Perhaps it has been due to the fact that when the mica was formed there was insufficient water taken up by the exterior portions to form perfect mica. This, however, is merely a speculation. There is, so far as I know, no published chemical analysis of the scaly exterior in comparison with the interior of the mica- blocks, and until we have such analysis, it is impossible to reach any definite conclusion. As previously noted, the action of water penetrating through the material of the dike produces an alteration in the feld- spathic contents, dissolving out the alkalies and leaving be- hind a hydrated aluminum silicate in the form of clay, while the mica and quartz are left untouched. Occasional Minerals. The pegmatite dikes, both of North Carolina and elsewhere, are noted for the number and variety of unusual minerals which they contain as accessories. A list of those occurring in the North Carolina dikes as prepared by W. C. Kerr, and cor- rected by F. A. Genth, is as follows :* *Notwithstanding the revision, it seems very doubtful if this list is com- plete. Rutile (titanium dioxide) is a common inclusion in micas. Pyrite is almost always found m granitic rocks, though I do not remember having seen it in the Carolina dikes. Common emerald occurs in some mica dikes, as that of Villeneuve, Quebec. Probably also ultramarines. Cassiterite (tin- stone) probably occurs here, as it certainly does in the dikes in South Da- kota and elsewhere. Kaolinite is, of course, often present as a derived product. Spodumene (hiddenite), corundum, cyanite, and topaz also are mentioned as occurring with mica in North Carolina. 288 Colies: [;. F. I., Albite Allanite Amazon stone( ?) Fluorapatite Autunite Beryl Magnetite Menaccanite Monazite Alnscovite Phosphuranylite Pyrochlore Rogersite wSamarskite Thulite Tourmaline Uraninite Uranocher Uranotil Y ttrogummite( ?) Columbite Fergusonite Fluorite Glassy feldspar( ?) Garnet Gummite Hatchettolite Limonite Many of these minerals are ores of the rare earths and ele- ments, like cerium, thorium and lanthanum, etc., used in incan- descent lamp mantels; uranium, used in the manufacture of fluorescent glass ; niobium, tantalum and other rare metals, in- cluding, perhaps, the now famous radium ; semi-precious gems, like beryl and tourmaline. These have formed from time to time a certain inconsiderable addition to the earnings of some of the mines. The question as to their source and meaning is certainly an interesting one, to which, however, so far as I know, no answer has ever been attempted. THE PYROXENIC MICAS. Whatever may be the origin of the micas in pyroxenic rocks, it is certain that it is very different from that of the micas just discussed. The difference is not only one of chemical compo- sition, but also of geologic structure and character. Magnesian micas are found associated with calcite (carbon- ate of lime) apatite (phosphate of lime), pyroxene (silicate of iron and magnesia), and hornblende (ditto). Although found in various parts of the earth’s surface, they are unique in being known to occur in workable commercial deposits apparently only in the Laurentian of Canada. The mode of occurrence of the Canadian mica deposits points to a more complicated mode of origin than that above assigned to the pegmatite likes. The magnesian micas do not loiirnal Franklin fnsL, Vol. CLX, October, igos {Colics) October, 1905.] 289 Mica and the Mica Industry- occur in normal pegmatite, although dikes of this material con- taining white mica are found in occasional deposits in their im- mediate neighborhood. The deposits of the magnesian micas and their associated minerals appear to be more in the nature of veins deposited through the principal agency of water, aided by some degree of heat. The country-rock consists principally of gneisses and metamorphosed and crystalline limestones. We find these country-rocks largely intersected by the veins of the associated mica-minerals, principally calcite and pyroxene, and these, as in the case of the pegmatite dikes, largely follow planes of the strata, but also cut across them both horizontally and vertically. The contacts between the vein material and the gneiss is often indefinite, indicating a widely extended impreg- nation of the latter by the former. These vein: instrusive masses appear to l^e true fissure veins in many respects, indicat- ing that the filling material was not under pressure, (i) The veins are frequently banded, and successive fillings alternating as pyroxene, calcite, etc., may be indicated. (2) The apatite and mica deposits are found in irregular pockets in the pyrox- ene, and the segregation of mica in shoots is common. (3) Void spaces forming chimneys and druses containing free crys- tals are of common occurrence. These could hardly occur under conditions of external pressure unless we suppose the presence of large quantities of gas or vapor. The presence of hot gases, moreover, is indicated in some places by the burnt condition of the chimneys. The veins do not die out in length or in depth, but they extend as far down as mining has yet been carried, amounting to from 300 to 400 feet in Quebec. The most important geological feature to note about these magnesian mica veins is that the mica occurs nea^'lv always on or near the contact surface between the pyroxene and one of the other rocks, especially calcite or gneiss. Dr. R. W. Ells, of the Canadian Geological Survey, has classified these deposits into three principal heads:* (i) Deposits between the pyrox- ene dike and gneissic country-rock ; (2) in pyroxene near the *“Mica Deposits of Canada,” by R. W. Ells, Bulletin C. G. S., 1904. A fourth class is given, defined as dikes of pyroxene cut by both calcite and pegmatite, but this variety does not seem to be either frequent or well de- fined, and is admitted by the author himself to be a form of class 2, hence it is omitted above. Voi,. CEX. No. 958 19 290 Colics: [J. F. L, contact of cross dikes of diorite or pegmatite (the mica of this class is ])ockety) ; (3) in pyroxene on and near a fissure plane. Though ai)parently inse])arable from pyroxene to any great distance, the matrix of the crystals is often actually one of cal- cite of apatite, which is interpolated between the pyroxene and the country rock. The calcite and apatite do not always occur, as the pyroxene does, but the best mica appears to be usually found in the deposits containing these minerals — best both in quality and size. From their nature, deposits of this class are very much more concentrated than in the case of the granitic micas. Instead of concentarted than in the case of the granitic micas. Instead of occurring in isolated crystals, it occurs in densely packed crys- talline masses, which form a vein in themselves without much Fig. 21. Ideal section of Magnesian mica vein. access of other material. These crystals are as a rule of small diameter and of very great length, but plates of immense size are common in some of the mines. These plates, like those of white mica, are frequently bent, twisted and flawed, but the rea- son appears to lie in the crow^ding of the crystals among them- selves rather than in the bending and folding of the strata in wdiich they occur. The crystals lie with their axes in all direc- tions, haphazard, and wdthout any observable arrangement ; and the sides of the crystals, that is, the edges of the plates, are for the most part not rough and ragged as in the case of the granitic micas, but are smooth, clean and polished. As might be expected from the solid interpacking of the material, voids in the interspace are of frequent occurrence. (See Fig. 21.) It is obvious that the contactual nature of the micas and their immediate association wdth pyroxene form the most important indices to the origin of the mica. Whether segregated from October, 1905.] 291 Mica and the Mica Industry- the elements of pyroxene alone, or whether formed by a new ehemical combination from these jointly with those of some other rock, it seems impossible to say with certainty, because an explanation that would do for one deposit would fail for another. The most probable theory seems to be that the mica is a surface crystallization upon the pyroxene and ■from materials contained in it while the latter was still in a plastic condition. That it could have been formed after the rocks solidified is clearly impossible. Age of the Canadian Deposits. The Laurentian hills, in which these deposits occur, belong’ not only to the Archaean age, but to the oldest recognized period of that age. It is generally held among geologists, fol- lowing the original theory of J. D. Dana, that this portion of the earth’s surface has been out of water nearly all the time since the strata were first raised, which raising is supposed to have taken place before the beginning of the Cambrian epoch. There are doubtless indications that this may have been the case, and also it may not be too much to state that proofs are lacking.* *In drawing his “Archaean Map of North America,” Prof. Dana simply drew in the Archaean areas of the present day as land, and everything else as water, stating that these areas formed the nucleus of the continent; which iorms a part of the argument for the semi-religious thesis on which his views of geology were based; and subsequently geologists seem to have simply adopted Dana’s views. In other words, the continent began with the present Archaean areas and continued in a general way evolving from this as a base to its present extent. As all subsequent formations have been derived from the Archaean this necessarily supposes that the material which went to form all the other deposits of the continent, from the Cam- brain to the Quaternary, were at one time heaped up on the present Archaean areas. So stated, the theory appears in its true light as nothing less than ridiculous. Besides, to suppose that the present Archaean areas constituted the first land is nothing less than impossible, for these rocks are stratified, and consequently, in the nature of fragmental rocks, were derived from other land, either by means of rivers or ocean currents, which other land must have existed before these Archaean areas were formed. Inasmuch, then, as other land than the present Archaean constituted the brst land of the continent, and the nucleus has been changed at least once, we may as well admit that it has been changed a hundred times. We do not know what is under the earth more than a few thousand feet, and if, dor example, some point in Arizona were subjected to a continuous rais- ing and denudation for a sufficiently long time, washing away one formation -after another until the Archaean was reached, it would offer a very similai condition to that of the Laurentian Hills, and no doubt ancient beaches, etc., would be found which would bear up the theory that this point formed the beginning or nucleus of the continent. 292 Colics: []. F. L, But the present area was, at all events, at one time covered with many thousand feet of superposed strata of some age. The question is, (i) were the mica deposits, etc., made during the Arcluean age and prior to the general metamor])hism of the rocks in which they occur ; or (2) were they deposited in subse- quent ages when overlain by rocks of later periods, and then metamorphized — being perhaps derived by infiltration from aqueous solutions bearing material from these latter rocks; or (3) have they been formed by aqueous deposits since the meta- morphism of the rocks, and never undergone any metamorphic action ? These questions are much more difficult to answer than the questions as to the origin of the granitic micas, and, in fact, a definite answer cannot yet be given. Certain con- siderations, however, point to the last of these three views as the most probable. The manner in which the veins intersect the strata of gneiss and each other, and the presence of chim- neys and voids, appear to indicate with tolerable clearness that the strata had been metamorphized and upturned before the veins were formed. For the same reasons the veins were prob- ably formed near the surface, and extended perhaps but a short distance (several thousand feet) below it. Expanding gases may have opened the rock-fissures and a heated magnesian- aqueous magma followed to fill them. This agrees tolerably well with the theory of Dr. R. W. Ells, of the Canadian Geolog- ical Survey, that the material was derived from igneous sources as submarine injections. This must have been prior to the laying down of the Cambrian and Silurian, which immediately overlie the Laurentian series and limit the exploitable area ; for no mica dikes are found in any of these. Rclaiion of ^ Mica Deposits to Archaean Age. Existing commercial mica formations appear to be exclusively confined to the Archaean rocks — though there may be excep- tions. We are naturally inclined to ask. Was there some peculiar geological condition acting in the Archaean, which produced these rocks, and which does not now exist ? I believe there is no need for such a hypothesis. A'e know that mica in small crys- tals occurs in crystalline rocks of all ages, and that such crystals are produced naturally in these rocks wherever the materials Black mica (biotite) from Gracofield, Ottawa County, Que. The plate measures 20x9 in. Jour. Fra7iklin Inst., Vol. CLX, October, ipoj 294 Colics: [J.F.I. for its formation are at hand, and the heat is continuously main- tained. \\- Q know that the Arcluean rocks differ from all later rocks in being universally metamor])hized ; but this is obviously ex])lainable in the same manner as the greater extent of meta- morphism among the i)rimary or secondary than among the tertiary rocks ; namely, that they have been more deeply buried tlian others ; and not hy invoking an extraordinary terpera- ture on the earth's surface in the earlier time.* As previously explained, the pegmatite dikes imply the burial of the rocks in which they occur beneath several, perhaps many miles of over- lying strata, a condition which could have been attained only by the Archaean rocks; or, if attained by others which exist to- day beneath the earth’s surface, the time has been insufficient to raise them and denude them sufficiently to expose the de- posits. This does not, indeed, explain the Laurentian micas^ unless we assume them also to have been formed at a great dis- tance from the surface ; but it should be remembered that these are the only deposits of magnesian micas of importance that have as yet been commercially worked, and that little as to their day or manner of origin can be certainly predicated at the present time. *The fact should be emphasized here, that the Archaean age was an age of land and water, of building up and of laying down, in every way similar to the present so far as concerns any evidence to the contrary, and was em- phatically not an “age of fire,’’ as it is frequently thought of as being. I have heard Archaean rocks tajked of, by persons who ought to know better,, as “plutonic,” meaning rocks which originated through cooling from a state of incandescence at the time that the globe first solidified from this state. The stratified condition of the rocks shows emphatically that this is not the case. If there was an “age of fire,” no evidence of it can be ob- tained from the rocks themselves, and it must have preceded the Archaean Age by at least as long a time as has elapsed since its close. Another common assumption is that the Archaean preceded the origin of life on this planet, and it has been called the “Azoic,” or lifeless age — because the Archaean rocks contain no recognizable fossils. Xo assumption could be more gratuitous. It would be, of course, a bootless task to search for fossils in granite, calcite and pyroxene, but fortunateh' there is abundant evidence for the existence of life of a varied and comparatively complex character in the Archaean. ( To be conthiued) Fig. 23. Normal amber mica (mottled), from Lacey mine, Sydenham, Ontario. This plate measures 23x17 inches lower edges are lines of natural ruling, hence the plate is but a fraction of the size of the entire crystal. four. Fra7iklin Inst., Vo/. CLX, October, /goj 296 Notes and Comments. [J. F. L, HEALING QUALITIES OE EGG MEMBRANE. At a recent session of the 'I'herapentical Association of Paris, Doctor Amat lectured on the use of membrane of eggs in the treatment of wounds. He has observed for some time the good results of placing these mem- branes upon the surface of wounds, and reports two new cases, that of a young girl suffering from a burn on her foot, and a man, forty years old, with a large ulcer on his leg. Both wounds are in process of healing, and were covered with healthy granulations. The surgeon overspread them with six or eight pieces of the membrane of eggs, which was covered with tin foil and fastened with dry antiseptic bandages. After four days the bandages and tin foil were removed, and it was shown that the membrane of the egg had partly grown into the tissues and had caused the growing of a good skin. That the egg membrane had contributed much to the healing process was demonstrated in the further course of treatment. It seems, however, that the membrane does not always adhere. The process of cicatrization is not only hastened but the wound heals exceptionally well and leaves but few perceptible traces. As these membranes are procurable everywhere their use should attract more attention. — Richard Guenther Consul- General, Frankfort, Germany. May 13. 1905. PREPARATION OF RAILWAY CROSS-TIES. The Revue Gcnerale des Chcniins de For describes the preparation of cross- ties by the Compagnie de I’Ouest by means of the injection of creosote. Works for the purpose are established at Surdon in the department of Orme, about the center of the railway system. The yard occupies more than eight hectares. The ties, on arrival at the yard, are classified accord- ing to their comparative resistance to the penetration of creosote, and are piled up so as to dry by means of a free circulation of air. This requires from six months to a year, after which they are placed in hot-air driers for twenty-four hours and afterward in large hermetically sealed injection cylin- ders. heated by steam worms, under a pressure of two kilogrammes, which allows of maintaining a uniform temperature of 80 deg, C. for the creosote. A vacuum is produced in the cylinders, which are put in- communication with the creosote vats. When filled with the liquid, an inside pressure of seven kilogrammes is caused by means of pumps for thirty-five or fort\--five min- utes. The annual production at Surdon is 297.COO cross-ties, and 200.0CO posts, stakes and other pieces. — Seimtific American. THE DISPOSITION OF TPIE BOSTON "FRANKLIN FUND." The Board of Aldermen of Boston. iMass.. has formally accepted the offer of Andrew Carnegie of an endowment fund of $400,000 to be used for the maintenance of a trade school to be established by the Benjamin Frank- lin Fund, which is the accumulation of a bequest by that eminent American made a century ago. The condition of Mr. Carnegie's gift is that the in* stitution be patterned after the Cooper Union, New York. October, 1905.] Sanitary Protection of Water Supplies- 297 Stated Meeting, held Thursday, April i8th, ipoy. The Sanitary Protection of Water Supplies* By Kenneth Allen. Chief Engineer Water Department Atlantic City, N. J. [Unsanitary conditions may be detected by analysis of water, by inspection of watershed or by mortality statistics. Knowledge of the life history of the typhoid germ and registration of vital statistics are important. Presumptive tests for B. Coli valuable. Corrective treatment may be applied by the individual but should be applied to the entire sup- ply. It may consist in: 1. Prevention of pollution; 2. Adoption of a pure supply; IL Purification of an inferior supply. Control by Boards of Health, with Federal control as a last resort, is sug- gested. In any case ample power and funds should be provided. In selecting method of securing pure water with limited resources do not strive for ideal results in some detail at expense of greater general benefit.— The Emtok.] It is with a feeling of diffidence that I approach the subject of sanitation with relation to \vater supplies in a city where it has been uppermost in the minds of the people for a genera- tion, where most eminent advice has been given with regard to the betterment of its own supply and where, finally, monumen- tal works to alleviate the intolerable conditions of the past are approaching completion. But it is one of those matters con- cerning which eternal vigilance is the price of safety, and, moreover, it is one in which a marked development is taking place ; and these are perhaps sufficient reasons for speaking on this subject to you to-night. It has been said that the three great evils to mankind in the past have been war, pestilence and famine. In spite of the in- creased efficiency of modern arms and the recent activity in the East this great evil is becoming less and less. This, as pointed out by Bloch, is partly on account of the fearful destructive- ness of scientific warfare from an economic point of view, but perhaps more on account of the rapid development of the humanitarian instincts since the first of the last century. Famine, too, is a thing of the past in all civilized countries on accunt of the ample facilities for transport of supplies and the transfer of news, due to the use of steam and electricity. And, compared with the Middle Ages, modern society may be said to be free from the horrors of pestilence. With ordinarily decent modes of living those terrible scourges the plague and typhus have become practically extinct ; with the general practice of Allen: [J. F. L, 298 vaccination smallpox is not to be feared as in the past; more recently the ])ro])hylactic pro])erties of specific serums are re- ducing' the mortality due to diphtheria and other diseases and by the extermination of the stegomyia fasciata and anopheles mosquitoes the spread of yellow fever and malaria in Cuba and Panama is being controlled. But in spite of all this progress in the prevention of disease the mortality from typhoid fever remains about 45* for each 10,000 inhabitants in the United States, and 52.8 in the case of Philadel]:)hia ; while it has been recognized for some years that this disease is due to a specific bacterium, that it is usually con- veyed by drinking water, and that it is what is termed a “pre- ventable” disease. Growth in our knowledge of the causes of disease and its prevention have kept pace with growth in general sanitation. At the beginning of the 19th century conditions and customs were tolerated in English towns that to us seem inconceivable, while the simplest means of avoiding infection were neglected in those cases where the direct relation of filth to disease was not evident. The case of the Broad vStreet pump, in London, whose clear, sparkling water caused in 1854 the deaths of 616 persons, is well known, yet even to-day it is hard to convince many that the danger in polluted water is generally invisible. Neverthe- less, especially during the past thirty years, the early years of bacteriology, appreciation of the relation between water sup- ply, filth, infection and disease has made rapid advances, and there is a marked demand for purer and safer supplies. What I wish to point out is the fact that the present attitude regard- ing this subject, as that regarding electricity, corporations, transportation, organized charity and prison reform, is essen- tially modern — so modern that as yet there is need of much edu- cational work and much effort to utilize the knowledge we al- ready possess. The problem confronting the sanitarian is two-fold: the deteetion of nnsanifary eonditions and their remedy. In the matter of public water supplies we wish to avoid in particular ingredi- *Estimated at 46.27 by Dr. Osier in 1890. who also estimated a rate of 17.9 for England and Wales, 65.8 for Italy, 47 for Austria and 20.4 for Prussia. October, 1905,] Sanitary Protection of Water Supplies- 299 ents prejudicial to health. Mineral poisons are seldom found but living organisms or theih products may be the vehicles by which most dangerous diseases are transmitted, and it is the detection of these that most concerns the sanitarian. And right here it will generally be necessary for him to call to his aid the expert services of the chemist, the bacteriologist and the biologist. But a few years ago, when it was found that the potability of a water could not be affirmed by its appearance, it was sup- posed that a chemical analysis would completely reveal its character. This is true in a general way only. Gross pollution is readily detected by analysis and water of high chemical purity is sel- dom to be feared ; but we now know that, in the dissemination of disease, bacteria, which are not discoverable by the methods of the chemist, play an essential roll. And while a public water supply should be free from sediment, color, objectionable tastes or odors, excessive amounts of iron, lime, magnesia or constit- uents that are capable of dissolving lead or other service pipes or fittings, the infection of a water supply by pathogenic bac- teria, as the most important phase of the question, is the one I shall dwell upon in particular detail. THE DETECTION OF UNSANITARY CONDITIONS. Unsanitary conditions regarding a water supply may be de- tected by an examination of the water itself, by making a sani- tary inspection of the watershed, or it may be revealed by the health and mortality statistics of the community served — espe- cially those due to intestinal disorders such as diarrhoea, ty- phoid fever and cholera. The first of these complaints is not often fatal and is generally readily controlled by ordinary care in diet ; cholera, although a most fatal disease, does not often obtain a foothold in well-regulated communities ; but typhoid is always with us. It is, then, to the suppression of this dis- ease more than any other that particular effort should be di- rected, and we may do this confident of success now that the cause of the disease and many of its characteristics are known. Typhoid fever is the result of the lodgment and development of the typhoid bacillus on the walls of the intestinal canal to which it is conveyed by our food or drink; and while cases and 300 Allen: [J.F.I., sometimes epidemics have l)een caused by infected shell fish, milk and other food stuffs that have become contaminated — perhaps by flies or by careless handling — the use of impure water is the most common source of the disease. It behooves us, then, to learn how our water supplies may become infected, how to detect such infection, what remedies to ap]:)ly and what precautions to take to guard against further infection. Prof. Sedgwick has said* that the germs “of typhoid fever are so few that all search for them by competent observers is usually in vain * * * . In comparison with the whole number of bacteria, those of typhoid fever are probably as rare as planets are among the stars, while, unlike the planets, they have no marked features of size or motion which enables them to be readily distinguished.’’ Although it may be said that the typhoid bacillus “has been found but by two or three competent o1)servers so far in ty- phoid-producing natural waters”! we have been made some- what familiar with its characteristics by recent studies by bac- teriologists of cultures derived from infected sewage or dejecta. From the standpoint of the sanitarian it is most important to ascertain the longevity of the typhoid bacillus under differ- ent conditions, especially in water, and the following are results that have been found by several observers : Frankland experimented on the life of the typhoid bacterium in the polluted surface water of the Thames, the soft, peaty water of Lock Katrine and hard water from a deep well with the following results : Days when last bacterium was observed. Thames. L. Katrine. Deep well. When placed in raw water. . . 9 19 33 Water sterilized by steam . . . 32 51 20 Filtered water II 39 II Mr. George W. Fuller has found that the “typhoid bacterium continues to live in the waters of the Merrimac river at Law- rence, in greatly diminished numbers, for a period of at least twenty-four days.:j: Another authority states that “in sterilized water typhoid ^Sources of typhoid fever in Pittsburgh — 1898. tRep. John A. Amyot, ALD.. San. Jour. Provincial Bd. Hlth., 1904. tinternational Public Health Congress — 1893. 301 October, 1905.] Sajiitary Protection of Water Supplies- bacilli do not multiply, but perish iu from one to three mouths, lu water where there is much organic matter they may live longer, but the ordinary water bacteria seem to destroy them speedily.” Perhaps the most reliable data regarding the longevity of the typhoid bacillus have been obtained by Messrs. E. O. Jordon, H. L. Russell and F. R. Zeit’ in a series of elaborate experiments made at the request of the Sanitary District of Chicago about a year ago. These are of particular interest from the fact that natural conditions or environment, including change of water, were employed by enclosing the organisms in permeable sacs of parchment or celloidin and immersing these at various points in Lake Michigan, the Chicago River, the Drainage Canal and the Illinois River. The soluble products of organisms existing in these waters were therefore brought into contact with the typhoid bacilli by osmosis while the bacilli themselves could not escape.* These gentlemen found that under these conditions ‘‘the vast majority of typhoid bacilli * * * perished within three or four days,” although “it is theoretically possible that specially resistant cells may occur which are* able to withstand for a longer period the hostile indnences evidently present in the water.” And they further conclude: I St. “That typhoid bacilli die out more readily in imsterilized water than in the same water sterilized by heat ;” and 2d. “That when typhoid bacilli are introduced into nnsteriliz- ed water containing little organic matter, their longevity is more prolonged than in water charged with considerable organic matter.” As to their survival during low temperatures. Professor Wm. T. Sedgwick says if “The latest and most trustworthy investigatigns on this sub- ject do not support the idea that any considerable number of cases, even in a large city using a comparatively impure ice sup- ply, can be traced to this source, and it is a remarkable and important fact that no epidemic or other excess of typhoid has ever yet been undisputably traced to infected ice.’” *Some doubt as to this last point has been recently raised by the results of experiments by W. R. Copeland at Columbus, Ohio. K. A. t“Source of Typhoid Fever in Pittsburgh.” — 1898. 302 Allen: [J. F. I., It ap])ears, however, tliat this l^acterium persists longer in cold weather than in summer. As a rule deep-seated soils are sretile; but sewage bacteria have been found at considerable depths when forced through a porous soil by continuous dosing on the surface. Mr. Fuller states that the typhoid bacillus has been found .alive in the soil after five and a-half months, and that it has been found at a depth of nine and a-half feet. Dr. Martin, of England, finds that “‘in certain virgin soils * * * the typhoid bacillus does not grow nor live under .any condition of the soil, sterilized or unsterilized,'’ but that “in' cultivated soils, /. c. those containing organic matter, that Fave been sterilized, the bacillus lives for a prolonged period and spreads through the soil. If, however, the bacillus be -added to a cultivated soil, sterilization of which has been omit- ted, the micro-organism cannot be obtained from such soil after twelve days or so.” Mr. George C. Whipple found, in examination of the sands ■of Long Island containing from 136,130 to 200,000 bacteria per c.c. at the surface, that at a depth of two feet there were but from 2,850 to 35,870 ; at a depth of 4 feet from 280 to 2,240, and .at a depth of 7 feet from o to 170. “These results,” he says, “indicate that below a depth of five feet the sand never contains more than a very small number of bacteria.” The longevity of this organism has a most important bearing -on the transmission of typhoid by flowing water and has ‘brought out elaborate arguments in testimony before the L". S. -Supreme Court concerning the effect of Chicago's Drainage •Canal on the water supply of St. Louis. Between the tendency •of this organism to die out and the eff*ect of dilution by the comparatively pure water of Lake Michigan it is argued that the waters of the lower Illinois and of the ^lississippi at St. Louis are actually rendered safer and more pure than before.* In fact, from a large number of analyses of the waters of the Illinois and Mississippi Rivers extending over the years 1897-1902, Prof. A. \V. Palmer finds that “‘although the quan- *AIr. John W. Alvord, assuming an average of 100,000 persons for every "twenty deaths on the various drainage areas determines “effective popula- “tions contributing pollution” of 3.750,000 at Chicago, about 2,000.000 at IPeoria after flowing five days and but 100,000 after flowing fourteen days. October, 1905.] Saiiiiary Protection of Water SnppHcs^ 3^3 titles or organic matters in the sewage now discharged into the Desplaines and Illinois Rivers are 30 per cent, greater than be- fore, the proportions of organic matters contained in the w^aters discharged by the Illinois River into the Mississippi are very considerably smaller than they were prior to 1900; and that the decrease of the proportions is not a mere dilution, is shown by the fact that the actual quantities of organic matters discharged are less than they were formerly.”* According to Messrs. Zeit and Flitters :t The Seine at 70 kilometers below Paris, the Oder 32 kilome- ters 1 )elow Breslau, the Isar 33 kilometers below Munich and the Limmat 14 kilometers below Zurich, are each as pure as before entering these respective towns. These gentlemen, after much experimental study, arrived at the following conclusions, the first of which, however, should be accepted with caution as not entirely in accord with the con- sensus of opinion among sanitarians, viz. : “A seriously polluted water becomes pure again after flowing a certain distance. Pathogenic bacteria and sewage bacteria decrease as organic matter decreases. At the same time water bacteria increase. The presence of saprophytes hastens the re- moval of organic matter and the death of pathogenic bacteria. “The quantitative bacteriological examination must give w'ay to the qualitative, because a few infectious bacteria per c.c. •constitute a more severe water pollution than a very great r.umber of water l^acteria.” According to Mr. Whipple, “The soil is the great repository ■of bacterial life, and every rainfall that washes the surface of the •ground carries countless millions of bacteria into the streams. Hence, after every rain the number of bacteria in the water ■supply increases. The heavier the rainfall the larger in general will be the number of bacteria found. * * * Speaking gen- erally, * * the numbers of bacteria in the Croton water measures the amount of surface wash into the stream, and Fence the chance of infection.”! Contrary to public opinion it will be seen that, so far as trans- mission of disease goes, the infection of a small rapidly-flowing^ *Chemical Survey of the Waters of Illinois — 1903. tSanitary Investig. of 111 . River. 111 . St. Bd. of Hlth., 1901. $Rep. Com. on Add. Water Supply for the City of New York, p. 378. Allen: [J. F. I., 304 stream is more to 1)e feared than that of a sluggish stream or reservoir. The great lakes receive untold polluting material, and yet furnish a wholesome water supply, except in the vicin- ity of towns. According to Whip])le, “A water ten days after infection is perhaps one-sixth as likely to cause disease as that water one day after infection, while in one month it is perhaps one-hftieth as great. The value of large storage reservoirs is thus evident.”* Moreover, as infecting material received by a small stream will be conveyed in a concentrated form, these require more vigilant inspection than large ones — other things being equal. The characteristics of large rivers are more permanent. In recent investigations into the filtration problem at Xew Or- leans it was found that the Mississippi River at this point, al- though receiving the drainag'e from the vast population on its drainage area, was comparatively free from bacteria and or- ganic pollution. It is partly on account of the use of small streams, although more particularly from the careless location of wells and the lack of supervision over water supplies and drainage, that ty- phoid is often spoken of as a rural disease. And from its pre- valence in the country on areas utilized, perhaps, for the collec- tion of public water supplies, the need of efficient sanitary in- spection of such areas is evident. Conceding that typhoid may be derived from polluted oys- ters, dust containing the typhoid germ or polluted milk; that cases may be imported from other cities or induced by careless nursing, it remains a fact that the typhoid mortality of a town is perhaps the best single test of the quality of its water supply. Why is it that Philadelphia, Pittsburgh, Allegheny, Troy, Albany and Washington have had typhoid rates in the past of from 65 to no per 100,000? And why is it' that Bos- ton, New York, St. Louis, Buffalo, Jersey City and Providence have had but 19 to 29 deaths per 100,000? while in Berlin, Hamburg, Munich, Dresden, Hanover, Leipsic and Cologne the mortality is but from 4.6 to 9 per 100,000? L^nquestionably because the first-named cities have had polluted water supplies, the second set supplies from good natural streams or lakes, *Report on Quality of the Present Water Supplies of Xew York City — 1904. 305 October, 1905.] Sajiifary Protection of Water Supplies- while the third set have supplies raised above suspicion. This opinion is confirmkl when we come to study the epidemics of typhoid such as those at Plymouth and Butler in this State, Lowell and Lawrence in Massachusetts, Ithaca, N. Y., and many others, where there is abundant evidence of the contam- ination of the water supply by typhoid dejecta. In the first of these 1104 cases and 114 deaths were directly traced to one typhoid patient, although the water had first passed through three storage reservoirs having a combined capacity of 5,- 000,000 gallons. Further confirmation is found in the relative typhoid mortality before and after the purification of the supply as has just been illustrated in your own city, Lawrence, Albany and Chicago. In Berlin, before 1883, the mortality from this cause was i in 9,000. After the introduction of filtration works the rate was reduced so that since 1893 it has been but i in 10,- 000, or half as many as in New York. In 1876 it was i in 10,850 in Philadelphia, while now it is but i in 1890. Yet another evidence that water is the chief cause of typhoid is mentioned l)y Dr. A. Seibert,* who attributes its prevalence in New York during warm weather — as has also been ob- served in the Prussian army — to the fact that more water is drunk at this time of the year, and that bacterial life is then more active and abundant. y Turning now to the lives sacrificed annually by typhoid, these probably aggregate in the United States about 50,000; in New York 425; in Chicago (previous to 1900) 900; in Philadelphia (1890-1900) 600, while the loss in dollars and cents to the State of Connecticut alone in 1902 has been estimated at twenty-five million dollars. Mr. John W. Hill, of your filtration bureau, has estimated the annual loss from typhoid in the United States at $278,000,000.1 It would seem only necessary to bring. the intelligent busi- ness men of the community to a realization of such losses and the possibility of their control to ensure every safeguard over our water supplies. It is most important that accurate statistics be kept of all *New York Medical Journal. tThe N. Y. Sun states that of 6,000 cases per annum in New York, half, occur in the fall and one-fourth in the summer. IThe Relation of Water to Typhoid Fe.ver, 1898. Vol. CIvX. No. 958 20 typhoid cases as well as deaths, for it is by noting an abnormal increase in these that we can best receive warning of an epi- demic, and by properly interpreting a comparison with corres- ponding figures for other towns, that we may be in possession ■of one of the most valuable factors required in forming an esti- mate of the potability of a given supply. Dr. A. C. Abbott, Chief of the Philadelphia Bureau of Health, has said that “of the data relating to suspicious water supplies, those which are most trustworthy and constant in their indications are the regu- larly recorded vital statistics of the community using such w'ater." For this reason it is most unfortunate that the registration of vital statistics is not compulsory in this State although there .are indications that this may be remedied before long. The pollution of a water supply may be indicated by the ex- amination of a sample of the water. Turbidity, color, odor and taste are sometimes indicative of its quality, but a chemical an- alysis is required to give quantitative results and to enable the expert to make a good guess as to the cause of pollution, if such be found, and whether it is recent or of long standing.* Zeit and Futterer state that “To establish the normal impur- ity of a river, the water level should be falling and no rains to increase the normal pollution * * * Bacterial purifica- tion of a river can be judged by the gradual disappearance of pathogenic and sewage bacteria with falling water level. f As a water used for drinking purposes should be judged when at its worst, however, samples should be taken both dur- ing a drought, or at least during a low stage of the stream, when impurities will be in a state of greater concentration, and immediately after a hard rain, when impurities will have been washed into the stream from the surface of the ground. Pollution is indicated by the amount of nitrogenous matter *Mr. X. H, Goodnoiigh states among numerous similar examples. (Re- port of Commission on Charles River Dam, 1903) “The waters of the Con- necticut River * * * not show any evidence to the senses of the pollution they receive after the sewage has entered the river at Holyoke, Chicopee, Springfield or West Springfield, excepting floating matters, chiefly from manufacturing wastes.” fReport to 111 . St. Bd. of Hlth. on Examinations of the Waters of the 111 . River, 1901. October, 1905.] Sanitary Protection of Water Supplies- 307 in a sample of water, by the decomposable organic matter as in- dicated by the oxygen into which it will enter into combina- tion and by the colorine above that found normally in the nat- ural unpolluted streams of the neighborhood.* None of these constituents is necessarily harmful, being rather indicative of pollution — past or present, vegetable or ani- mal. As to the interpretation of the analysis, this should be done with great care and only considered final after confirma- tion by ah expert. Even then the chemist may fail to discover the direct cause of disease — pathogenic bacteria, and it is nec- essary to turn to the bacteriologist for aid. Bacteria are present in surface waters in countless numbers. The limit for a good drinking water has been placed at from 100 to 300 per c.c. Those ordinarily found are called saphro- phytes, and are generally considered harmless, while others — pathogenic bacteria — are known to cause specific disease.** Sewage may contain as many as thirty-five million per c.c. ; rivers vary greatly, but may contain from several hundred* to as many thousand; ordinary wells four or five hundred, while the waters of Lake Superior contain but from twenty to thirty per c.c. and artesian wells none.f Now, although the dejecta of a typhoid patient may contain *Rough limits of these several constituents for a drinking water may be taken as the following in parts per million: Chlorine 10 above normal Albuminoid Ammonia 0.02 Nitrates oo 5 Nitrites None Oxygen consumed 4 **Bacteria are also classed as aerobic (normally requiring oxygen) and anaerobic and as liquefying (those which liquefy solids) and non-liquefying bacteria. Of 440 varieties known, 196 are liquefying bacteria. In sewage there have been found, per cubic inch (cc?): 5 million anaerobic liquefying bacteria 12 “ “ non-liquefying bacteria 8 “ aerobic liquefying bacteria 77 “ “ non-liquefying bacteria •or about 100 million in all. fAs to their size it has been estimated that it would take about 53,000 to weigh a grain. The tvohoid bacillus, which was discovered by both Eberth and Koch but 25 years ago, is about 50600 inch in thickness and several times as long. Allen: [J. F. 1., 308 as many as 2,000,000,000 typhoid bacilli per gram* it has been pointed out that by dispersion or death these are not readily found in even a grossly polluted water. Fortunately a more persistent bacterium universally found in the intestines of man and animals, known as the Bacillus Coli, affords an excellent means by which we may infer pollution from animal sources and hence danger as a conveyor of disease germs. Presump- tive tests are therefore usually made for this bacterium. So universally is this’ found in surface waters, however, that per- fectly good supplies may give positive tests with 10 c.c.f Mr. Whipple suggests the following provisional scale by which the character of surface water may be judged according to the B. Coli it contains : If found in 100 c.c. the water may be assumed as safe ‘‘ “ 10 c.c. “ “ “ “ reasonably safe “ “ I c.c. “ “ “ “ questionable “ “ o.i c.c. “ “ “ “ probably unsafe. “ “ o.oic.c. “ “ “ “ unsafe With regard to well waters the presence of this organism “is an almost infallible indication of the presence of contamination with surface water. J The identification of other forms of bacteria in the examina- tion ofl water supplies is as a rule deemed superfluous and not attempted in this country, although it is recognized of much importance* in studies of sewage purification. Of several characteristic sewage bacteria it may be said, how- ever, that strepococci survive in the soil but a short time; B. Coli disappear as a rule rapidly, but certain ‘‘strains” may sur- vive for weeks or months, while B. enteriditis sporogenes ma}^ persist for long periods. The first two, therefore, indicate re- cent pollution — the latter, if alone, pollution in the past.** In general, it may be said that chemical and bacterial exam • illations are mutually supporting, that the former are of great- est value in detecting conditions liable to cause offense to the senses, while bacterial examinations are of greatest value in de- termining the safety of a drinking water. *Hazen, Filtration of Public Water Supplies, 1898. tGeorge C. Whipple. “Quality of the Present supply of Xew York City.” — 1904. :i;Technology Quarterly, March, 1903. **See report of Royal Com. on Sewage Disposal, 1905. October, 1905.] Sanitary Protection of Water Supplies- 3^9 Examination of water supplies is regularly made now by most cities of importance. Chemical analyses are made by Baltimore, Brooklyn, Buffalo, Chicago, Newark and New York; bacterial examinations by Albany, Buffalo, Denver, Hartford, Lawrence, Newark and New York; and biological examinations by Albany, Brooklyn, Boston, Lynn, Pittsburgh, Buffalo and Wilkesbarre. There remains a third way in which the contamination of a water supply may be detected, which consists in a sanitary survey, or at least an inspection, of the gathering area. In- deed, in all surface supplies a vigilant oversight of possible sources of contamination should be 'regularly maintained. Where the area drained is of great extent this may be limited to a careful examination of premises within a few miles of the reservoir or intake and a knowledge of the character of the drainage area — whether cultivated, wooded, rocky and hilly, or otherwise — the population and the general features of the sewerage systems of towns draining thereto. Although a water once contaminated cannot be considered safe even after flowing a great many miles, yet the further the source of con- tamina-tion the less the danger : first, because in almost all nat- ural streams the effect of dilution will be to decrease the pro- portion of impurities ; secondly, organic matters will, by natural processes become mineralized and pathogenic bacteria die out, and thirdly, because by the sedimentation that is going on more or less at all times organic matter is entrained with the rest and carried to the bottom. Baumeister has determined the impurities received by sewers (in Europe) to vary from 4.2 to 8.1, averaging 6.7, ounces per capita, about half of which is from human sources ; and in order to compare the probable conditions of streams into which sys- tems of sewers discharge he has deduced a formula for what he terms its “coefficient of pollution,” which in English measures may be expressed as follows : Let E = the population on area drained C = proportion of population tributary to sewers. Q = discharge of stream in cubic feet per twenty-four hours. V = mean velocity of stream in feet per second. P = coefficient of pollution. O V Then P E(i+C) 310 Allen: [J. F. L, He has used this in arriving at the relative pollution of vari- ous European rivers and various points in the same river. Careful investigations have been made on the sanitary condi- tion of watersheds now utilized for the supplies of Boston, Xew York, Philadelphia and Pittsburgh. In that of the Delaware watershed made by Mr. Rudolph Hering under the administra- tion of Col. Ludlow, twenty years ago, a map was prepared containing a red dot for every looo persons, which illustrated in a very graphic w^ay the relative density of population found in the valleys of the Schuylkill and Lehigh Rivers as compared with those found on the area draining to the Upper Delaware. The following are the results obtained in several instances : Total Area Sq. Mi. Popula’n per Sq. Mi. Ohio River(Cincinn: ati) 1898 75,700 4.56 Croton River 1904 338.8 52 Monongahela “ 1900 7,600 24 Allegheny “ 1900 11,400 24 Nashua “ 1894 118 58* Mahoning Cr., (Youngstown, O) 967 77 As already stated, the character of a drainage area and that of the stream itself have great influence on the amount and character of its pollution. In a general' way, however, it may be said that where the population exceeds 300 per square mile the water wdll be so contaminated that the supply will not be satisfactory,t while, with a population exceeding 125 per sq. mile, the water is open to suspicion.** In the absence of available records of population we may assume for every o. i part per million of chlorine above the nor- mal, a population of twenty-one persons per square mile of watershed! — a relation calculated some years ago by ^Ir. F. P Stearns, now Chief Engineer of the Metropolitan Water Board of Boston. The intimate relation between density of population and typhoid fever has been shown very clearly and graphically with reference to the Hudson River, by Messrs. Burr, Hering and Freeman in their recent report on a future supply for Xew *Excliisive of site of proposed reservoir. fRep. Mass. State Board of Health, 1890. **Dr. S. W. Williston in Rep. Conn. State Board of Health. ^Examination of Water Supplies Mass. St. Board of Health, 1890. October, 1905.] Sanitary Protection of Water Supplies- 31 1 York by plotting the total population and deaths from typhoid as positive and negative ordinates, respectively, with corres- ponding abscissas in miles. The typhoid mortality on the drainage area is, therefore, an important factor in the contam- ination to be expected in a stream. In a sanitary survey note should be taken of the character and volume of trade wastes, as from tanneries, wool and dye works, breweries, sugar refineries, paper mills, etc. ; of the drainage from barn yards, cesspools, fertilized lands and swamps ; especially in the vicinity of the intake. In some cases deterioration of a supply is caused by deposits of organic matter — sludge, sawdust, etc. — in the bed of the stream or reservoir from which it is drawn. But such de- posits, the inspector should remember, are not always cumula- tive, decomposition tending to balance the increment, so that a stable condition of such deposit is no proof that deposition is not constantly taking place. Several centuries ago the Thames was so clogged in this way that large vessels were un- able to reach the city of London. The investigations of Dr. George W. Soper of the possible sources of contamination of the Ithaca supply during the epi- demic of 1903 is of interest in this connection as illustrating the grossly unsanitary conditions that can exist on the very out- skirts of a University town of above the average character, im- perilling the lives of the inhabitants. Of some 14,000 inhab- itants 1350 were taken sick and (S2 died within about three months. In repeated cases privies were noted draining di- rectly to the water supply of the city. Had these premises been under competent inspection possibly the Water Company would have more fully realized in advance the terrible risks being taken. The three chief sources of information from which we may form an intelligent opinion of a water supply are, then : 1. The typhoid rate among consumers. 2. Examination of the water itself. 3. Inspection of the watershed with reference to possible sources of pollution. The first of these should always be watched, the second should be applied at such regular intervals as appear desirable, and the third is of especial value in cases where possible sources 312 Allen: [J. F.I., of pollution — especially those of a temporary nature — may ex- ist within several miles of the reservoir or intake. With full information from these three sources those in authority will be enabled to intelligently select and apply such measures to remedy the situation as are proper. THE REMEDY FOR UNSANITARY CONDITIONS. Corrective treatment in the case of a polluted water supply may be applied by the individual consumer. He may attach a Pasteur or Berkefeld filter to his faucet, which, if carefully at- tended to, will remove unwelcome bacteria. He may boil or distill the water, which is safer yet, and then, by adding drops of muriatic acid diluted to lo per cent, strength and two grains bicarbonate of soda to each gallon, make it again palatable. Or, finally, he may sterilize it by contact with copper — a very sim- ple remedy recently described by Prof. Henry Kraemer in the American Journal of Pharmacy, consisting merely in the im- mersion in the water of a piece of copper foil about 3^ inches square to each quart tobe purified for from six to eight hours.* Prophylactic measures left to the option of the individual are always evaded by a large proportion of those most in need of them and are impracticable to enforce. The remedy must be applied on a large scale — to the water supply as a whole. In the remedy, as in the detection of unsanitary conditions, there are three general courses that may be pursued, viz. : 1. The prevention of pollution. 2. The adoption of a pure source of water supply. 3. Purification of an inferior supply. The question of stream pollution is becoming* a very pressing one in the thickly settled parts of this country as it* has been for some time abroad. It is one requiring broad and judicial treatment. The questions of a legal and scientific nature that are involved cannot be safely left to popular opinion, even if free from bias. Experience would seem to indicate that re- sponsibility in the preparation and enactment of laws and in their execution should be vested in a competent board or com- *Sterilization after infection has taken place has been tried successfully by Dr. J, E. Woodbridge b}' the administration of specific medicines and is of much interest but hardly pertinent to this discussion. October, 1905-] Sanitary Protection of Water Supplies- 313 mission, but there is considerable diversity in the ways by which it is sought to control the pollution of water supplies in different states. This is, and should be, undertaken by those directly in charge of water works without dependence on out- side aid. Every corporation supplying water to a community should satisfy itself as to its original quality and take meas- ures to avoid any subsequent deterioration that may occur. In the application of such measures not only sewage but storm water effluents should be diverted from the supply. The anomaly may be noted that, while the activity of its contained bacteria tends to purify water percolating to lower strata the percolation of a good water through a considerable distance of the top soil may cause its deterioration, and that long contact with surface moulds, as in overflowed swamps, is liable to injure a water ; so that in constructing reservoirs the top soil is often removed at considerable expense ; that very shallow reservoirs, exposing a large surface to both the underlying soil and the heating effect of the sun, are to be avoided, while very deep reservoirs are also objectionable, as the deeper portions cannot avail of the sunlight and air for their purification. If the area is not too great a regular patrol of the watershed and examination of samples should be maintained, as is done in Brooklyn, Providence and Baltimore. Unfortunately there are water works where these matters, not being compulsory, are neglected. In this case the value of a competent Health Board becomes apparent, having power to formulate and execute such measures, however drastic, as are required for the public safety. There is a very great diversity in the composition and au- thority granted health officials in this country, and much legis- lation governing these matters is antiquated. In spite of marked diff'erences the State Boards of Health of Massa- chusetts, Connecticut, New York, New Jersey and Ohio may perhaps be selected as those taking the lead to-day in securing effective results. In Massachusetts, New York and Ohio the local authorities are required to consult with and may receive advice from the State Board, while in the latter, at least, such advice may be mandatory. In the above States and New Jer- sey and Connecticut the Board is expected to investigate all new supplies and in the case of Ohio this is mandatory. 314 Allen: [J. F. I., It is believed that in minor matters the local health officers, or, at most, these and the water works officials by cooperation, will be able to secure proper conditions if given adequate au- thority. But in matters so vitally related as the sanitary condi- tions on a watershed and the health of a city’s population there should be some central authority in control of both; and this generally takes the form of a State Board of Health, which, as has been remarked, has proven very satisfactory in several States. In those cases where a supply is taken from a stream head- ing in or flowing to another State, new complications arise, and so serious may these become that a great city like Xew York is forced to abandon as a source of supply the one recom- mended by Mr. John R. Freeman) as that having the greatest advantages — Ten-Mile River in Connecticut — from fear of legislation. The following opinion rendered on this point by the Com- mittee on Legislation to the Engineering Committee of the Merchants’ Association of New York in their comprehensive investigation of the question about five years ago is of inter- est :* ‘Tn our opinion the City of New York has no right to divert the flow of the Ten-Mile River from the State of Connecticut, nor to divert the flow of the Rampo River from the State of New Jersey, and in case of such diversion of the Ten-iMile River a lower riparian owner on the river in Connecticut could enjoin the proposed diversion in an action either in the United States Courts or in the Courts of New York State.” Also, “We are of opinion that the City of New York cannot acquire any power of preserving drainage basins from pollution in the State of New Jersey, except by purchase.” It is a question whether the difficulties in the case might not have been overcome by compensation to riparian owners or else resort to the Federal Courts if a strong sentiment in favor of this plan had existed among those in authority. Nevertheless this suggests the desirability of providing in- terstate regulation in order that an important city may avail itself, if necessary, of far-lying water supplies, though naturally *The Water Supply of New York, 1900, pp. 452, 476. October, 1905.] Sanitary Protection of Water Supplies- 3^5 tributary to other nearby towns without resort to litigation. The inadequacy of artificial political boundaries is to a certain extent recognized in Great Britain, where officials in control of matters pertaining to stream pollution are given jurisdiction over certain drainage areas instead of a county or other arbi- trary area. In the matter of water supplies this plan may in certain cases fail to be quite perfect because areas draining to surface streams and those draining to underground supplies may be far from identical. In a general way, however, juris- diction extending over drainage areas would appear most feasi- ble and desirable ; and in order to adjust questions arising where this area lies in two or more States it is evident that, un- less unconstitutional, general control should be vested in some central authority. In discussing this matter Mr. J. S. Haring has said :* ‘The only way to make the purification of water supplies effective is to first prevent, by Federal laws, the pollution of rivers and streams. Too many of our rivers are in the jurisdiction of more than one state to make the state control of these matters effective. * * * Only a general law, irrespective of State or city, can prevent effectually what will be in a few years, if it is not in some places already, an evil of great magnitude.” Interstate legislation would fail to overcome difficulties promptly and without friction. It is suggested that, inasmuch as the U. S. Geological Survey contains a most efficient body of engineers, who have already done a large amount of valuable work in studies pertaining to hydrology, stream flow, stream pollution and artesian well sup- plies, and is now taking up extensive constructive work in con- nection with irrigation, it would provide admirably the cen- tral authority sought; while interstate disputes could be re- ferred by the Survey to the Federal courts, and matters con- cerning local pollution left, as at present, to state or local boards of health. For the application of such a system of control some plan such as the following, suggested several years ago,t might be adopted. This provided : *Trans. Am. Soc. C. E., Dec., 1899. tTrans. Am. Soc. C. E., Dec., 1899. 3i6 Allen: [J- F. I., First, that all streams should be classified according to their permissible contamination as follows : Class L Streams far from populous centers and not likely to be used for manufacturing or domestic purposes. Class’ II. Streams likely to be used for other than domestic purposes. Class III. Streams likely to be used for domestic purposes. And second, a responsible officer should then be selected who should supervise and control all sources of pollution throughout the drainage area of every stream in which pollu- tion is restricted by law. The Survey or the officer in charge should, according to some well-considered plan, fix the limits of contamination in each case. It should also act as referee in questions relating to the appropriation of water supplies by different municipalities so as to secure the most efficient and equitable -results, including those relating to the rights to underground supplies. For condemnation of water rights lying outside the district in which the town or corporation seeking it is located, power would have to be obtained from the central authority. The present Royal Commission on Sewage Disposal has had this question of the rights to natural supplies referred to it, and has suggested placing all necessary powers with proposed Rivers Boards, each Board to have jurisdiction over a group of drainage areas. It may be said here that Speaker Nixon of the New York State Assembly has recently proposed a plan quite similar to that mentioned, allotting certain definite areas to each city in its search for water ; while Governor Higgins suggests a State Commission to have jurisdiction over all water supplies, their apportionment and protection. Whether power is vested in a special commission, a Health Board, or otherwise, it should be granted ample authority with funds to enable it to carry out its provisions effectively. It should be brought into close relations with its local agents, and these, in turn, should cooperate so as to secure the best results. Referring to this State, which has suffered in the past from typhoid in both epidemic and endemic form, the Engineering News says “to put matters plainly . (Pennsylvania) is well known among sanitarians to be notably backward in all mat- October, 1905.] Sanitary Protection of Water Siipphies. 317 ters concerning the protection of the public health” and this is attributed, not to the character of its officers, but to want of liberality in' the legislature in granting adequate power to the State Board of Health, to local authorities and to water com- panies.* According to Dr. Chapin, of Providence, it is desirable that the township should constitute the unit of sanitary control; that where, is in New England and Ohio, the township is well developed sanitary control is most successful ; but that where this is weak — more dependent upon the county organization — as in Pennsylvania and the South — sanitary control is apt to be feeble and ineffective. As to the personnel of the controlling body I quite agree with Prof. Sedgwick, who says: “The appointment of an engineer of distinction to membership in the State Board of Health (of Massachusetts) * * * 1886 marked a new epoch in san- itary administration and has been followed by the happiest re- sults. Other States have since followed the example of Massa- chusetts and with uniform advantage. * * * A good board of health should be very carefully chosen, should include in its membership one or more expert physician, at least one good engineer, and one good business man. Nothing less will answer for any progressive city in which health and decency are rated at their full value.” A reasonable control over the pollution of natural water sup- plies may be secured by/ invoking the common law, but statu- tory legislation is necessary to ensure purity sufficient for do- mestic purposes. Some of the more usual and important statu- tory laws prohibit the direct fouling of a supply by excrementi- cious or other decomposing organic matter, the discharge therein of sewage or other foul liquors, presence of privies, stables, manure heaps, cemeteries, etc., within a certain dis- tance of the shore, or bathing in the waters of a stream or lake used for a wacer supply. Thorough disinfection of all dis- charges from those suffering from typhoid on the watershed should be required. Lack of this simple measure is no doubt the cause not only of much typhoid derived from drinking water, but of a considerable dissemination of the disease by *The State Board of Health has, since writing this, been reorganized' with enlarged power, promising effective results in the future. Allen : [J. F. L, 318 means of flies and dust in the rural districts; and each addi- tional case there is an additional menace to the water supply. Quite as important but more difficult to control is the dis- semination of typhoid by those who have the disease in so light a form that they are not confined to bed, by the many cases that are not recognized as typhoid or are incorrectly diagnosed, and by convalescents who may unconsciously continue to spread the germs for many weeks after recovery.* Attention should be directed to the water served in railroad trains. Unfortunately many towns are supplied with water that is positively dangerous to use. If the tanks in a train are filled in such a town travelers over many miles of territory may unwittingly place their lives in jeopardy by drinking it, and if sickness ensues the cause may never be suspected. To provide the greatest protection to surface supplies some cities have gone so far as to buy up entire watersheds at great cost. In England, Manchester has secured 11,000 acres in this way, Liverpool has obtained authority to buy 22,000 acres and Birmingham 45,000. In Scotland, Glasgow has secured an agreement from the landowners that on 20,000 acres no leases* shall be made for building purposes, while nearer at home,. Bal- timore has been considering the question of acquiring the watershed of its supply from the Gunpowder River. But aside from legislative control much may be done by those in charge of water supplies by securing possession of and fencing in marginal areas of streams and reservoirs; diverting or even purifying storm water effluents (which are sometimes very foul), by providing and maintaining a suitable depth in reservoirs, by removing vegetation from the water and its shores, draining swamps on the watershed, removing muddy deposits from the bottom and by providing ample storage. Surface waters undergo a marked improvement in storage under proper conditions, as impurities settle out and bacteria — especially pathogenic bacteria — diminish rapidly in number. As an illustration examinations of the Croton supply have shown an average reduction in bacteria in passing through the Central Park reservoirs of 45 per cent., while a further reduc- *172 million germs per c.c. have been found in the urine of a typhoid con- valescent. See Petruschky in Centralblatt fur Bakteriologie, 1898. October, 1905.] Sanitary Protection of Water Supplies. 319 tion of 29 per cent, takes place in the mains before reaching City Hall Square. The reduction found in the numbers of Bacilli Coli was even more marked.* To prevent pollution, then we should seek the aid of the State through legislation and Boards of Health and those in direct charge of water supplies should take such measures as will not only prevent deterioration of such water after taken over into their hands, but, if possible, improve its quality. With increasing density of population it becomes imprac- ticable to avoid such contamination of surface supplies that they are unfit for domestic purposes. At such a time a stream of Class HI (as proposed) would be placed in Class H, and towns depending thereon for a supply would be forced to one of two courses of action — either to seek some new and unpol- luted source or to adopt some method of purifying the exist- ing source ; and it is believed that the time will come when all large cities will be forced to accept one of these alternatives. Consequently the development of ground water supplies will be more actively and scientifically carried out than heretofore. Already they are utilized to a considerable extent along the coastal plain between New York and Florida and in the Missis- sippi Valley. The difficulty of securing an artesian supply in- creases rapidly with its extent so that, although Brooklyn, Cam- den, Savannah, Galveston, Memphis and other towns obtain a great part of their supply in this way, it is in smaller towns that we find its greatest development. Serious objections sometimes met with are excess of iron, requiring its removal, as at Red Bank, N. J. ; excess of soda, which discolors starch so that the water is unsuitable for culinary and laundry purposes, as at Charleston ; excess of carbonic acid, by which lead service pipes are attacked, making tin-lined pipe necessary, as at Atlantic City, and a decrease in capacity frequently occurring from the clogging of the strainers. These may all be of so serious a na- ture as to render recourse to a distant surface supply prefer- able. London proposes a water supply from Wales, and Liverpool, Manchester, Glasgow, Boston and New York have gone many miles to secure satisfactory surface supplies. *Rep. of Com. on Add’l Water Supply, 1904, p. 380. 320 A lien : [J. F. I., A pure natural source is always to be desired, but failing in these there remains the possibility of purifying a polluted sup- ply, usually by filtration. Within the last fifteen years filtra- tion has been placed on a correct scientific basis and is gener- ally accepted as safe and satisfactory if only the works are prop- erly designed and operated. While Europe has taken the lead in the introduction of filtra- tion, we have probably surpassed her in excellence of design in our most recent works, and in magnitude those of Philadelphia will head the world’s list. The adoption of filtration by Albany, Jersey City, Philadelphia, Pittsburgh, New Orleans and Louis- ville would be a sufficient guarantee of its efficiency if its re- sults in reducing typhoid were not already known. As alternatives there are boiling, distillation, deration, sedi- mentation, treatment with ozone and with sulphate of copper. The first two of these are not applicable to a city’s supply on account of cost. Either sedimentation seriation — at one time in use here for the Schuylkill water — may improve the appear- ance and taste, but will not make a polluted water safe. There are several ozone processes, one of which has been in use by the city of New York in, sterilizing sewage efffuents on one or two of the Croton watersheds for a number of years. It is believed to do this effectively, but that its applicability in any given case will depend on the cost. The very simple and inexpensive method of sterilization by the use of copper sulphate, suggested by ^Messrs. iMoore and Kellerman, of the Department of Agriculture, and applied with success at Baltimore and elsewhere appears to be of particular value when used judiciously to, remove contamination of a tem- porary character — either for offensive algae or bacterial impur- ity. Its effects are marked and rapid. Dr. ’^loore cites a case* where “a spring, which was accidentally polluted, and which gave rise to over fifty cases of typhoid in less than a week (in which) the use of copper sulphate completely sterilized the water, and it was possible to continue using the spring within five hours.” One part to ten thousand parts of water, it is said, will de- stroy typhoid and cholera organisms in three to four hours. Eng. News, Feb. 9, 1905. 321 October, Sanitary Protection of Water Supplies. while one part in two million is generally sufficient. A 1 ai e destroyed by one part of the salt dissolved in from 100,000 parts of water in the case of Beggiatoa to twenty-five million parts in the case of Spirogyra. Some very noteworthy results were obtained from its use in the polluted water of the Scioto River, supplying Columbus, Ohio. Previous to treatment the colon bacillus was rarely absent from the water. From August 19th till December 30th, 1904, daily tests showed the samples to be free from this organism. January 5th, owing to alarm caused by the newspapers, treat- ment was discontinued. The consequent result as shown by the following tabular statement is strong testimony to the value of this method of treatment — at least as a temporary ex- pedient — for the sterilization of an infected water:* June, Water not treated 24 July, “ “ '■ 33 August “ treated after the 19th 52 September, “ “ 16 October, “ “ 16 November, “ “ 8 December, “ “ 4 t January, “ not treated after the 5th 91 February, “ “ 376 To March 27, “ “ 279 So far, the Massachusetts State Board of Health has failed to recommend this method for general application, probably through fear that by carelessness so large an amount of copper might be used as to be prejudicial to health, and for this reason it has been recently unfavorably reported in connection with the supply of New York City.| To decide whether to adopt a new supply or to improve the *Copper as an Algicide and Disinfectant in Water Supplies, Bulletin 76, Bureau of Plant Industry, 1905. fSeventeen cases reported, but only four used city water. More recent investigations indicate limits to the efficiency of this treat- ment, depending on temperature, quality of water, etc. K. A. $‘‘If this process be carefully conducted such growths (of algae) may be safely prevented in this way, but this Commission is decidedly opposed to the use of copper sulphate in the Croton supply, because, remaining in the water, if carelessly introduced, it might endanger the health of consumers. The report of Messrs. Hazen and Whipple contains similar conclusions. Report on Filtering the Croton Water. Burr-Hering-Freeman, January i6th, 1905. 322 Allen : [J. F. I., present one is often a serious question, and one that usually re- quires the services of the expert engineer. If the present source is not seriously contaminated, and if an artesian supply is avail- able, there is the choice between purification of the former, the development of a ground water supply or of securing a new sur- face supply. Either may be entirely satisfactory as to quality, and it is probable that a comparative estimate will eliminate one or possibly two from the question. While a surface supply may be said to be always in need of inspection, this is-no less of a filter plant ; and although artesian wells be considered the safest of all, yet these have been known to receive serious pol- lution by hidden channels tapping contaminated surface water. It is noticable that while English towns generally depend on protected surface supplies, in Germany filtration is general and in France there is a marked tendency to secure underground supplies. We cannot always secure the ideal supply but must do the best under existing circumstances. It may be said that no amount of dilution will make a stream once contaminated absolutely safe for drinking purposes ; but we must bear in mind that all surface supplies are open to this criticism and, while the trend of public opinion is setting strongly toward filtered or underground supplies it will neces- sarily be many years before we can hope even to approximate such ideal conditions. We should, however, throw such safe- guards about our surface supplies as will ensure the greatest practicable protection. In striving toward our ideals it is wise to consider the cost -of each and then secure the greatest possi- ble good with our available funds, leaving if necessary their ab- solute fulfillment to future generations. In the meantime we need not allow our ideals to fade or be lowered. While placing matters of greatest moment on a monetary basis — if you will — this way of securing the greatest good to the greatest number is, after all, both the scientific one and good common sense; and if a town with but $10,000 to spare can save more lives by providing a pest house or by introducing sewers than by per- fecting its water supply, I would say build the pest house or sewers first by all means, and defer the desired improvements to the water supply. It is a business question — a matter of estimate. ( )ctober, \go=. | Notes and Comments. 323 DISCUSSION. Dr. Henry Leffmann : — The many difficult problems that confront the municipal hydraulic eng-ineers have been so well presented in the paper that further discussion is unnecessary. I desire to express strongly my approval of the author’s en- dorsement of the value of chemical analysis of water intended for drinking purposes. When, about a quarter of a century ago, bacteriology took a sudden lurch into prominence, it was claimed that it would set aside chemical analysis. Koch said that such analysis is mere ethics. Naturally, it was thought that water-borne diseases are most likely to be due to minute organisms, the detection of which would be possible and suffi- cient. It soon appeared, however, that these organisms are very elusive, and, after many mistakes and some untruthful- ness, bacteriologists are prepared to admit that the most im- portant water-borne disease germ, that of typhoid fever, is practically not discoverable in ordinary waters. For the val- uation of well and spring waters, chemical analysis is still essen- tial. The data, chlorine, nitrates and nitrites give us infor- mation as to where the water has been and how long ago, points of great sanitary moment. I have long regarded the analysis, bacteriologic or chemical, of surface waters as of little practical value. It seems that each community must learn the lesson for itself, that unfiltered surface water that has been col- lected or has flowed through even a sparsely-settled district, is unfit for drinking purposes. In discussing the biology of the typhoid bacillus, it must be borne in mind that the researches are made with organisms that have been obtained from human viscera or discharges and not from water. I think that great caution should be observed in applying the biologic data ob- tained in this way to practical problems in water sanitation. ARTIFICIAL SILK. In the Consular Reports issued by the Department of State there has recently appeared an interesting note on the production of artificial silk by Mr. Richard Guenther, Consul-General at Frankfort, Germany, from which the following extract is made: “For more than one hundred and fifty years efforts have been made to find a cheap substitute for genuine silk. At last cellulose has been found to be suitable fdr producing brilliant threads of silk-like appearance. The best 324 Notes and Cofuments [J. F. I., kind for the purpose is carded cotton, which was used by Count Hilairede Chardonnet, the first manufacturer of large quantities of artificial silk. German chemists, among them Dr. Lehner, of xA.ugsburg, also have ■solved the problem of making artificial silk. The chief difference between the processes of Chardonnet and Lehner is that the collodion from which the product is made is of a different character, and that in the process of Chardonnet the collodion is spun dry. Dr. Lehner spins his collodion wet and then lets it dry. The associated factories of artificial silk of Frankfort-on-the-Main. com- prising two factories in Germany and two in Switzerland, which have a com- munity of interest with the Chardonnet factory at Besancon, in France, use the process of Chardonnet and Lehner. There is also a company at Elber- feld under the name ‘Vereinigte Glanzstoff-Fabriken in Elberfeld/ which •owns several factories in Germany and uses the processes of Dr. H. Pauly, Dr. M. Fernery, J. Urban, and Dr. E. Bronnert. The last process differs from the other decidedly. Cellulose is dissolved in ammoniated oxide of copper and is then directly separated from this solution by means of an acid in the form of threads. In order to arrive at a conclusion as to how far artificial silk can replace natural silk in the manufacture of silk goods, it is necessary to compare the physical and chemical qualities of the natural and artificial product. Under the microscope all artificial silks differ from the natural in their greater thicknesses. Tussah silk alone resembles artificial silk. Artificial silks, without exception, possess the quality of at once distending largely in water, which increases their thickness one-third to one-half, while natural silk does not distend perceptibly. This distending seems to be the reason that artificial silk, in a wet state, loses so much in firmness. The artificial silk manufactured by the two associations named shows qualities which come very close to those of natural silk and excels it in some respects. The product is of an even white color, of a silky touch, and when pressed together has even some of the characteristic crackle of genuine silk, the so-called silky cry. It greatly excels natural silk in brilliancy. The chief use of artificial silk is in the passementerie industry. For passe- menterie goods and for trimmings it has proven so suitable that for such purposes it is even preferred to natural silk. For embroidering it is the ideal material; its high luster and adaptability to the form of the embroid- ery add a most brilliant look to such work. In the manufacture of straw hats artificial silk takes the place of straw. The hats made of it excel the ordinary straw hats in brilliancy. A separate branch is that of imitating hu- man hair, called ‘meteor,’ made of artificial silk. Such imitation hair is as soft as the natural growth and cannot be distinguished from it; it is, further- more, cleaner and cheaper. The price of natural human hair is often twenty-five times as high as the artificial article, besides the latter is not as heavy as the former. Artificial silk finds to-day an increasing market even in the silk-producing countries.” October, 1905.] Book Notices. 325 Book Notices. Die Darsicllung dcs Zinks auf elektrolytischem Wege. Von. Dr.-ing. Emil Guenther, Hiietten-Ingenieur, Aachen. ]\Iit 59 in den Text gedruckten Abbildungen. (8 vo. pp. xii A 243). Halle a. S. Driick und Verlag von Wilhelm Knapp. 1904. (Price, 10 marks.) The foregoing volume constitutes the sixteenth of the series of Mono- graphs of Applied Electricity issued by this publisher, nearly all of which have received notice in the Journal. The profitable production of electrolytic zinc has thus far proven to be a most troublesome problem to solve, and much more study and experiment will be required before it is satisfactorily solved. This volume here noticed will be found most useful in giving the investigating reader a complete re- sume of the processes thus far proposed for the solution of the zinc prob- lem, and of the results actually accomplished. The profitable solution of this problem would be one of the most important economic achievements in the field of metallurgy. W. PUBLICATIONS RECEIVED. Hydrology of the State of New York. By George F. Rafter (New York State Museum, John M. Clarke, Director. Bulletin 85. Economic Geology 12.) Albany: New York State Education Dept. 1905. 8vo., pp. 902. (Price, $1.50.) Locomotive Testing Plant at the Louisiana Purchase Exposition, St. Louis, Mo. 1904. (Penna. Railroad Co.) Schiff and IVasser. J. F. Becker, Schiffbauteschnisches Bureau, Hamburg. 1905. Report of a Fire, Sand and Water Test made upon a 20x22 foot span, hollow tile, grooved arch floor, constructed by the National Fireproof Company at Pittsburgh, Pa. By Ira H. Woolson, M. E. (Price, 25 cts.) Renold Roller Chain. Booklet No. 54, 1905. Link Belt Engineering Co., Philadelphia 12 pages, illustrations, 8vo. Armour Institute of Technology Year Book for igo 5 -igo 6 . Chicago, Armour Institute of Technology Press, 1905. 195 pages, portrait, plan, 8vo. Geological Survey of Kentucky, Charles J. Norwood, Director. Bulletin No. I. Preliminary part. The Oil and Gas Sands of Kentucky, by J. B. Holing, Lexington, Survey 1904. 233 pages, illustrations plates, maps, quarto. Proceedings of the Nineteenth Annual Meeting of the Conference of State and Provincial Boards of Health of North America, Washington, D. C., June 3 and 4, 1904. Providence: Snow & Farnham, 1904. 78 pages, 8vo. School of Industrial Art of the Pennsylvania Museum. Circular of the School of Applied Art. Twenty-ninth season, 1905-6, Philadelphia. 56 pages, 8vo. 326 Proceedings— Committee on Science and the Arts. [J- F. I., Concrete Steel. A treatise on the theory and practice of reinforced concrete construction. By W. Noble Twelvetrees. With numerous illustra- tions, designs and tables. 8 vo. pp. xii, 218. Whittaker & Co., London and New York. 1905. (Price, 6 shillings.) The use of reinforced concrete has, within recent years, worked some- thing of a revolution in engineering construction. This development has received its most active and successful impulse in this country, and it is accordingly a notable circumstance that one of the few contributions relat- ing to the subject should come to us from the press of an English publisher. ' W. Franklin Institute. (Abstract of Proceedings of the Stated Meeting held Wednesday, September 20th, 1905.) Hall of the Franklin Institute, Philadelphia, September 20th, 1905. President John Berkinbine in the chair. Present, 43 members and visitors. Additions to membership since last report, 13. Mr. Lindon W. Bates, of New York, described and illustrated with the aid of models several modifications of the present plans for the construc- tion of the Panama Canal, for which he claimed special advantages. (The communication will appear in the Journal.) Mr. Andrew Wright Crawford and Mr. Frank Miles Day, representing the organizations allied for the acquisition of a comprehensive park system for Philadelphia, presented some interesting data with lantern photographs, exhibiting the present status of the work. The President expressed the thanks of the meeting to the speakers ol the evening, and adjourned the meeting. Wm. H. Wahl, Secretary. Committee on Science and the Arts* (Abstract of Proceedings of the Stated Meeting held Wednesday, September 6th, 1905.) Mr. Samuel Sartain in the chair. Present, nine members. The following reports were presented and passed first reading: (No. 2339.) The Walter Szvitch. Dr. B. W'alter. (No. 2366.) Piiel Saving Piirnace and Method. The Fuel Saving Co., Utica, N. Y. These reports were held under advisement until the next stated meeting. The resignation of Mr. Daniel Eppelsheimer. Jr., as a member of the Cimmittee, was ])resented and accepted, with a vote of regret. On motion of Mr. L. E. Levy, the Chairman was authorized to appoint a special committee to prepare a memorial of the late John Carbutt, one- time member of the Committee. W^i. H. Wahl, Secretary. Journal of the Franklin Institute — Advertisements. ix WE ARE OFFERING A LIMITED NUMBER OF SETS OF A Special 3 Vol. Edition Handsomely Bound in Half florocco, Cloth, Marbled, for $ I 5 Net (F- O. B. N. Y.) SPON’S ENCYCLOP/BDIA —OF THE— Industrial Arts, Manufactures and Products EDITED BY Q. Q. ANDRE, F, Q. S., Asso=IVl. Inst. C. E. AND C. Q. WARNFORD LOCK, F.L.S., F.Q.S., M.I.M.M. Assisted by many prominent flanufacturers. Chemists and Scientists The encyclopaedia is written by practical men for practical men. 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' The Tay or-Newbold Saw street, ch.cago in Inserted Cutters treated by the Taylor- White process, under exclusive rights. 30 cutters in 36 ins. Saw may be changed in 12 minutes. A set of Cutters hardly dulled in tw^o weeks’ con- tinuous cutting night and day. !£ MOOBE il WHITE CO. PHILADELPHIA PA., U. S. A. BCJIL-DCRS OR R3per=making Mschinery Friction Clutch Pulleys Cut=off Couplings, Etc. PHlLA'DELPH rAl ' MAN GAN ES E B R O N Z E, ::^/; 5 :pH‘ 0 SPHOR b rctnze; ■?■; ^^cAND; BAB B IT# M ETAtS . ..O? c i.Brass';and Phosphor Bronz^e Casfings ;v ; : - from y^lbL.To 10000 lbs. in' vyreighT. Journal of the Franklin Institute — Advertisements. xiii Morse, Williams & Co. Philadelphia EhEVflTORS BRKNOHES: NEW VORK RITTSBURO NEW HT^IZEN B7^:i-TI7V^ORE BOSTON MTL-KNTJq: J. E. LONERGAN c£ CO. 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TIRES STEEL TIRED WHEELS SOLID FORGED ROLLED WHEELS FORGINGS CASTINGS SPRINGS THE STANDARD STEEL WORKS HARRISON BUILDING PHILADELPHIA, PA. The Williams New Model Improved Enlarged A Writing Machine Made to Meet the Requirements of tuese Modern Times STRICTLY VISIBLE WRITING DIRECT INKING PRINTS LIKE A PRESS STANDARD TYPEWRITER EXCHANGE General Agents 1022 Arch Street, Philadelphia, Pa. SPECfALisTS IN Factory Building WILLIAM STEELE & SONS CONTRACTORS and BUILDERS 1600 Arch Street Telephone Connections PHILADELPHIA No.e xviii Journal of the Franklin Institute — Advertisements. THE JOHN SCOTT Cegacy IDedal and Preminm The City of Philadelphia holds in trust under the legacy of JoKn Scott, of E-dinbur^K t a sum of money, the interest of which is to be used for the encour- agement of “ingenious men and women who make useful inven- tions.” The legacy provides for the distribution of a Medal, inscribed “TO THE MOST DESERVING,” and Money Premium in the sum of $20 to such ..persons whose inventions shall merit the same. The examination of the inven- tions submitted for the Medal and Premium has been delegated by the Board of City Trusts, of the City of Philadelphia, to the Franklin Institute, and the Institute, under the competent as- sistance of its Committee on Science and the Arts undertakes to make the investigations free of charge and to rec- ommend for the award all meritorious inventions. Application should be addressed to the SECRETARY OF THE FRANKLIN INSTITUTE, from whom all information relative thereto may be obtained. Pursuant to the regulations for the award of the John Scott Legacy and Medal Premium THE FRANKLIN INSTITUTE, OF THE STATE OF PENNSYLVANIA has under consideration favorable reports upon accompanying ap- plications. Any objection to the proposed awards, or evidence of want of originality of the invention, may be communicated to the Secretary of the Institute within three months of the date of notice. COCHRANE FEEDWATER HEATERS There are more than enough Cochrane Heaters in present service to equip looo H. P. plants at every mile post between New York and San Francisco. We could not have sold .so many “Cochranes” but for the fact that these appliances have been ap* proved, adopted and recommended by the leading consulting and mechanical engineers and the lead- ing steam users, who use them because these heaters give the desired results. HARRISON SAFETY BOILER WORK^ 3142 NortU ITtli St., Philadelphia, Pa. Gold Medal Louisianna Purchase Exposition HARRISBURG ENGINES 6 TO 3,000 HORSE POWER HIGH SPEED, MEDIUM SPEED AND CORLISS Harrisburg Foundry and Machine Works HARRISBURG, PA. The Philadelphia Commercial Museum DR. WILLIAM P. WILSON. Director Supplies DETAILED, SPECIFIC INFORMATION concerning the TRADE CONDITIONS of the WORLD’S MARKETS. It tells WHERE THE MARKETS ARE and by whom supplied. Who the RESPONSIBLE BUYERS ARE, and HOW TO REACH THEM. It can ascertain FOR YOU the particular REQUIREMENTS of any or all the markets in THE LINE OF GOODS YOU MAKE. It has inaugurated a most valuable method of REGISTERING AMERI- CAN BUSINESS HOUSES IN FOREIGN COUNTRIES by means of Card Index Files placed in the CHAMBERS OF COMMERCE in FORTY-FIVE of the PRINCIPAL COMMERCIAL CENTERS OF THE WORLD. This is a movement in the Interest of American Commerce with which YOU SHOULD BE IDENTIFIED. Write for particulars to THE PHILADELPHIA COMMERCIAL MUSEUM 233 SOUTH F=iOURTH STREET, F=HIL-7=CDEL.RHIK Established 1828 Incorporated 1876 I. P. MORRIS CO. Port Richmond Iron Works PH I LAD EILPH I A Manufacturers of Machinery, Boilers and Tanks Heavy Machinery a Specialty BLACK DIAMOND FILE WORKS Twelve Medals Awarded at International Expositions Special Prize Gold Medal at Atlanta, Ga. 1895 G. & H. BARNETT CO., Philadelphia, Pa. See our exhibit in the Bourse, Fifth near Market St., Philadelphia UNIVERSITY OF ILLINOIS-URBANA Copy of Catalogue will be seut free to any interested file user upon application