The governor, which maintains a constant speed of the record cylinder anti the feed screw, consists of a light frame secured to the tattle, carrying a spindle on which the device is mounted. Loose on the spindle near the right-hand end of the frame are a disk and pulley, made in one piece ; a belt from the treadle passing over drives the governor. The driving puller which gives motion through a belt to the instni Men t, is fast on the spindle, and is formed with a boss on the inner• side. A third disk is bell in contact with the leather facing on this latter by a strong spiral spring abutting against the boss of the ndley, and a disk close to the cross arm keyed to the spindle. Pinned to the ends of this ai•m are the two weights, and two short anus project from them at the point where they are pinned to the cross arms, the end engaging in a groove formed in the boss of the disk. Two small pins pass from these arms throligh the boss on the arm, and into the disk against which the spiral spring presses. It will be seen that this spring holds the disk in close contact with the other• disk—sufficiently so that when motion is transmitted from the treadle to the pulley, the governor is caused to revolve, and a belt from the pulley to the instrument gives the desired motion to the cylinder and driving screw. So long as the speed continues normal, the instrument is driven at the rate for which the different parts are arranged, but should an extra velocity be given, t lie weights of the governor open slightly, and the pressure between the disks is reduced so that the speed falls instantly, So nicely are the various parts aljnsted that with the most ordinau•y care, the normal rate of 160 revolutions per minute. to which the instrument is speeded. need never• be exceeded by more titan one or two revolutions.
The OramophoPe.—Among the instruments for recording and reproducing speech and other sounds, the invention of Mr. Emile Berliner•, of Washington, D. C., knotvn as the gramophone, is remarkable as being distinct from the others in both form and prin ciple. The gramophone was one of the early modern talk ing machines. It was nearly perfected when the latest form of appeared. Since that time it has been improved, and we understand that recent trials of the in strument in Europe have proved very successful.
Fig. 3 shows the record ing apparatus ; Fig. 4, the reproducer ; Fig. 5, a print of a gramophone record.
In this machine a central apertured disk of zinc is used •for receiving the record. The disk, which is covered with an extremely thin 111111 of wax, is mounted on a vertical spindle within an etching trough which revolves with the spindle. The recording style, the diaphragm, and the mouth of the tube are mounted on a carriage, which is moved toward the centre of the zinc disk by a screw, taking its motion from the spindle carrying the disk. Motion is imparted to the record disk by a friction wheel on the horizontal shaft at the right of Fig. 3. This shaft is provided in the present case with a hand crank, by which the plate is revolved.
The same shaft is also pro vided with a pulley for re ceiving a belt front a snit able motor, when it k desired to operate the machine by power.
As the record disk is re volved, sounds uttered in the mouth-tube cause the dia phragm to vibrate, and the style is moved in a direction parallel with the face of the record surface, forming in the was film a sinuous line representing the sounds uttered in the mouth-tube, As the plate revolves, the style and parts connected with it are earned forward toward the centre of the disk, thus forming a spiral, sinuous line in the wax film. When the record is complete, the style is removed, and acid is admitted to the etching trough from the bottle supported at the right of the machine. As soon as the plate is sufficiently etched, the trough is removed, the acid is returned to the bottle, the wax film dissolved off, and the plate is trans ferred to the reproducing apparatus shown in Fig. 4.
In this apparatus the record plate is mounted on a vertical spindle, and revolved as in the other case. The diaphragm of the reproducing instrument carries a style which follows the spiral groove in the plate, thus cansing vibrations in the diaphragm, similar to those produced by the sounds uttered in the mouth-tube of the recording instrument. The diaphragm cell and reproducing style are carried upon the smaller end of the trumpet, which is delicately pivoted on a standard, and counterbalanced so that the reproducing stylus exerts only a slight pressure upon the record plate. The volume of sound issuing from the trumpet is great. Instrumental and vocal music are faithfully reproduced. It is obvious that the records formed by this instrument are permanent, and thd plates capable of being stored in a very small space. The possi bilities of extending the gramophonic principles are perhaps more noteworthy than its present development. The disks can be easily duplicated, and at an exhibition in Philadelphia an electro type copy of a 12-in. disk was shown which sounded precisely like the original. Since then talking copies have been made by matrice iqo molten glass, but the liability of the glass to slick in the form—the matrice being of copper—and the consequent warping of the glass copy, has proved a serious objection. Steel ma trices have been suggested as liable to overcome Ibis difficulty. Very successful copies have been made in celluloid from electrotype matrices, and such celluloid copies are particularly free from all frictional noise, provided the celluloid is pressed hard. and of well-seasoned mate rial. Gramophone records have been and such prints have been photo-engraved, and the copy thus olitained sounded precisely like the original. The important subject of good articulation has ever been kept in the foreground, and this is now in so satisfactory a shape that the inventor has carried on a vocal correspondence with friends in Europe, by means of small gramophone disks, which can be mailed in a good-sized letter envelope.