Edmund Arthur Engler

“ To railroad-men and watch-makers as a matter of necessity, to manufacturers and business-men as a matter of economy, and to individuals as a matter of convenience, it has come to be highly important to know what is the exact time of day to the second, in circumstances where half a century ago it would have quite sufficed to know the minute or even the hour. ”

“ The standard clock is an astronomical regulator with mercurial pendulum and dead-beat escapement, and closes an electric circuit at the sixtieth second of each hour. Another regulator, technically called "Lobby," is for use in case of accident to "Standard." They are so connected that a single failure of "Standard" to send out a signal at the proper time brings "Lobby" into action for the next signal, and, in order that "Lobby" may always be ready for service, an intentional breakdown of "Standard" occurs automatically at eight each morning, and the nine o'clock signal is sent out by "Lobby" ”

“ The box being placed above the center of oscillation of the pendulum, the addition of a weight makes the clock go faster and the removal of a weight retards it. By repeated experiment it has been ascertained what change each weight, under given conditions of atmospheric influences, will produce in a given time; so that the operator knows how to adjust the weights in every case, and the clock can be kept running on mean time with the greatest attainable accuracy. ”

“ At a central point a steam-engine drives pumps which compress air to five atmospheres in a reservoir holding eight cubic metres. This compressed air is sent, by means of a special regulator, into a second receiver called the "distributing reservoir," where the pressure is kept constant at seventh tenths of an atmosphere, or a little less—a pressure determined empirically to be sufficient to move the dials. The "distributing reservoir" is opened to transmit an impulse into the pipes each minute, for about twenty seconds, by a distributing clock (Fig. 4) . ”

“ Of the instruments which served their purpose in the discovery of the properties of the carbon button, a brief description will be given in this paper.
Sound is known to be produced by vibrations, generally of air; differences between sounds are due to differences in vibration. There are but three essential characteristics to be noted, all dependent upon the vibrations of the air: 1. The pitch, by virtue of which a sound is called high or low, and which depends upon the number or rapidity of the vibrations; 2. The intensity or loudness, which is determined by the amplitude of the vibration ”

“ C is a piece of carbon placed between two metallic plates which are connected with the battery, B, in whose circuit is also the galvanometer G. As the current passes it must go through the carbon, the pressure on which can be varied by changing the weights placed upon it. The deflections of the galvanometer-needle indicated that the resistance of the carbon varied inversely as the pressure to which it is subjected. The best arrangement proved to be to make the resistance of the circuit 6⁄10 of an ohm, while the normal resistance of the carbon itself was three ohms. ”

“ At the Paris Observatory a very fine standard clock or astronomical regulator is kept running on correct mean time by transit observations, being provided with the most approved self-compensating apparatus, and being further corrected daily by the adjustment of weights to the pendulum. ”

“ With the telephone, as with an ordinary telegraphic instrument, there is a limit beyond which it fails to be of service, but with the telephone this limit is sooner reached than with the ordinary instruments. ”

“ The bell is an ordinary electric bell, and is rung by the regulating clock, which closes the circuit at the instant the signal is desired. The flashing-signal consists of a red vertical disk on a vertical axis, which normally shows only its edge, but is made to revolve once on its axis in four sudden jumps, by simple mechanism in connection with electro-magnets, when the regulator, by closing the circuit, sends the current. ”

“ Delicate manometers indicate the pressure at all times, and the most approved electric apparatus is used to indicate the particular point at which a defect has occurred. A skilled engineer is on the watch at all times. Provision is also made so that, in case of any interruption in the regulator, the dials may be run by hand. Accuracy of time is secured by daily comparison with the observatory clock. ”

“ That the greater delicacy of the lampblack is due to the fact that it is so finely divided has been confirmed by experiments made with gas-retort carbon, the particles of which are comparatively coarse, graphite, which is more finely divided, and lampblack, whose particles are the finest of all. The changes of resistance for a given change of pressure were found to be proportional to the number of particles in a given volume, or inversely proportional to the size of the particles. ”

“ When A speaks he depresses his push-button p connecting his primary and tertiary, which completes his local primary circuit passing through the transmitter, where the electric impulse is transformed, as it were, into electric waves of varying number and amplitude by the peculiar property of the carbon button as varying pressure is put upon it by the vibrating diaphragm actuated by the voice. ”

“ The pendulum carries a small permanent magnet which swings over a resistance-coil about 116 inch distant. The coil is connected with the commutator in the test-box (Fig. 11) , consisting of a clock commutator with plugs for "Standard" and "Lobby," a current commutator with plugs for "Fast" and "Slow," and a small time-piece, shown at the top. The time-piece has only a minute-hand, and is made so as to stop itself and break circuit at XII, but closes circuit when running. The working is thus: Suppose "Standard" is found to be slow. ”

“ Edison estimated that there could not be less than 10,000,000 points in contact in the carbon-button when used in the telephone. This must, however, be regarded only as an approximation.
The only defect in the carbon button is its friability. But, when properly armatured, it need receive no violent shock, and will last as long as necessary. Even if it should happen to become cracked, the volume of sound would not be materially lessened. Experiments have been made to harden the button by mixing various substances with the carbon, and then subjecting the mixtures to high temperatures. ”

“ A firm standard, A, holds at its upper end a screw which works against a follower, H, to which is attached the metal cup, I. At the base, between two platinum plates, a, a, is the carbon, C; the platinum plates are in a battery circuit provided with a galvanometer. Upon the upper platinum rests a metallic cup, D. Between the two cups, I and D, is placed a piece, E, of any material upon which experiment is to be made. The expansions and contractions of E cause changes of pressure upon the carbon, and thus changes of resistance in the electric circuit which are indicated by the galvanometer. ”

“ The capacity of the two instruments last described for transmitting sounds seems to depend upon the fact that the current is made to pass through an imperfect contact, which, when acted upon by the vibrations of sound, gives to the current an undulatory character. Successful experiments have been made with loose-jointed machinery used as a transmitter. Even a common nail laid loosely across two other nails, insulated from each other but connected with a battery, will make a good transmitter. ”

“ Trials were made with wires of different thicknesses, and it was found that the results improved as the thickness of the wire was increased, until finally the best results were obtained by using a piece of solid material rigidly secured to the diaphragm and ivory plate. It then occurred to Mr. Edison that, inasmuch as the working of his instrument depended upon changes of pressure only, there would be no need of having a vibrating diaphragm at all. A heavy diaphragm was therefore constructed and rigidly fastened to the carbon disk, so that the loudest tones would produce no vibration in it. ”

“ The error of the standard clock is determined daily by comparison with the Greenwich signal. An ordinary dotting chronograph is set to the standard clock, and the Greenwich signal makes a dot on the chronograph-dial which gives at once the error of the standard and can be read off at leisure. ”

“ The brass will expand more than the steel, and, the rods being bent downward, the weights will be lowered. As the pendulum swings the weights swing with it, and are continually trying to get back to a horizontal position where they would balance each other; if they were swinging alone, they would evidently swing faster than the pendulum, and therefore, being attached, they accelerate its motion. If the steel were uppermost, the weights would be raised with an increase of temperature and the pendulum retarded. ”

“ An arm projecting from this axis moves the seconds-wheel one tooth forward each second; proper gearing gives motion to the minute and hour wheels.
The mean solar standard, besides controlling other clocks, to be enumerated later, drives a seconds-relay (a, Fig. 5) , which controls a mean-time chronometer (c) .
All the clocks controlled by the mean solar standard are required to indicate exact Greenwich local time; the error can not therefore be allowed to accumulate, and the means of correction are provided. ”

“ It is but one of the evidences of the advance of civilization that exact methods of dividing and measuring time are now in demand, not only by scientists and professional men as formerly, but by persons in the most ordinary pursuits of life. ”

“ With this arrangement the articulation was perfect, and, because the comparatively large area of the inflexible plate produced a greater pressure upon the carbon for a given tone than could be obtained when only the one point of the plate or diaphragm was used, the volume of sound was so magnified that a whisper three feet from the instrument was distinctly intelligible at the other end of the line.
Besides greater simplicity of construction, the carbon telephone possesses advantages over all others. ”

“ This may be due to the increased value of time when measured by the number of events or the magnitude of operations which modern ingenuity is capable of crowding into a given interval; there can be no doubt that a second to-day records a greater stride in the world's progress than did many hours in the days of our ancestors. ”

“ MANY of the discoveries of science which at the time are regarded merely as refinements—very interesting, but without practical value—sooner or later find their special uses in supplying wants before unfelt. ”

“ The ball in falling sends a "return" signal to the observatory. The record shows that about once in two months high wind prevents the raising of the ball, about once in six weeks it fails to fall on account of some fault in the electric connections, and about once a year it drops out of time. Under such circumstances it is dropped correctly at 2 p. m.
By special arrangement with the observatory a few London jewelers receive the hourly Greenwich current on private wires. ”

“ A piece of vegetable carbon plunged when incandescent into a mercury-bath, so that it becomes impregnated with particles of mercury, when placed in the tube, works quite well; pure vegetable carbon, on the contrary, is useless on account of its high resistance. ”

“ Thus, corrections must always be made in nice work for errors in the instrument or its setting—such as the level, azimuth, and collimation corrections—for personal equation of the observer, and for aberration; these corrections, however, only aid the observer in ascertaining the exact instant when the star actually crossed his meridian and do not in any way affect the principle already given. ”

“ Besides being used as a delicate thermometer, the tasimeter also serves as a means of determining the coefficient of expansion of bodies; for, by having a micrometer screw attachment, the amount of expansion can be readily determined. By turning the screw, when the needle has been deflected, until it is brought back to zero, the increase in length can be read by the number of turns or parts of a turn the screw has been moved. ”

“ When the signal arrives, the electro-magnet attracts its armature, and the two pins are brought close together. The mechanical operation will be understood by reference to Fig. 12, where a side elevation, a plan, and a front elevation are shown. This apparatus is fastened to ordinary clocks just back of the dial-plate (Fig. 13) . A curved slot is cut through the dial for a short space on each side of XII, and through this the pins project. ”

“ It is proposed to use this instrument in determining the changes of temperature in steam cylinders, the laws of motion of a fluid whose temperature is not uniform, the rapidity of mixture when fluids of different temperatures are brought together, and the number of thermal units in any given volume of fluid. ”