SCIENTIFIC RECREATIONS. 



fectly reproducing the same, the inventor devised an apparatus in which a 

 plate replaces the cylinder. This plate, which is ten inches in diameter, has 

 a volute spiral groove cut in its surface on both sides from its centre to 

 within one inch of its outer edge ; an arm guided by the spiral upon the 

 under side of the plate carries a diaphragm and mouthpiece at its extreme 

 end. If the arm be placed near the centre of the plate and the latter 

 rotated, the motion will cause the arm to follow the spiral outward to the 

 edge. A spring and train of. wheel-work regulated by a friction governor 

 serves to give uniform motion to the plate. The sheet upon which the 

 record is made is of tin-foil. This is fastened to a paper frame, made by 

 cutting a nine-inch disc from a square piece of paper of the same dimensions 

 as the plate. Four pins upon the plate pass through corresponding eyelet- 

 holes punched in the four corners of the paper, when the latter is laid upon 

 it, and thus secure accurate registration, while a clamping-frame hinged to 

 the plate fastens the foil and its paper frame securely to the latter. The 

 mechanism is so arranged that the plate may be started and stopped 

 instantly, or its motion reversed at will, thus giving the greatest convenience 

 to both speaker and copyist. 



"The articulation and quality of the Phonograph, although not yet 

 perfect, is full as good as the Telephone was. The instrument, when per- 

 fected and moved by clock-work, will undoubtedly reproduce every condition 

 of the human voice, including the whole world of expression in speech and 

 song, and will be used universally. 



"The sheet of tin-foil or other plastic material receiving the impressions 

 of sound, will be stereotyped or electrotyped so as to be multiplied and 

 made durable ; or the cylinder will be made of a material plastic when used, 

 and hardening afterward. Thin sheets of papier mac/ie, or of various sub- 

 stances which soften by heat, would be of this character. Having provided 

 thus for the durability of the Phonograph plate, it will be very easy to make 

 it separable from the cylinder producing it, and attachable to a correspond- 

 ing cylinder anywhere and at any time. There will doubtless be a standard 

 of diameter and pitch of screw for Phonograph cylinders. Friends at a 

 distance will then send to each other Phonograph letters, which will talk at 

 any time in the friend's voice when put upon the instrument." (Scribner^) 



The MICROPHONE (an outcome of the Telephone) was discovered by 

 Professor Hughes, of London. It is an instrument which in its main 

 features consists of a carbon " pencil," so suspended that one end rests upon 

 a carbon " die." The instrument being connected with a Telephone by the 

 circuit wires, will reproduce faint sounds very distinctly. Once a Microphone 

 was put into a preacher's pulpit, and joined to a private telegraph wire which 

 led to a gentleman's house. The owner was thus enabled to hear the 

 sermon. So long as it is thus connected every minute sound, even a fly's 

 footstep, will be faithfully reproduced. 



