60 Scientific Intelligence. 
forms of sending apparatus, all including the principle of mul- 
tiple vibrating points or surfaces of contact. This simple 
apparatus was very sensitive, and reproduced with fidelity con- 
versation in a low tone at a distance of more than thirty-five 
feet from the box; its performance suggested to me the multi- 
plication of the carbons on the re ay. 
above I may add that when the electrical current 
introduction of a pure. musical note, which often runs through 
considerable variation in pitch. This voltaic tone may be due 
to the repulsion exerted by the electrical current on itself, 
causing one of the carbon points to rise and fall with coqulanal 
in a manner analogous to the motion of the Trevelyan rocker, 
or it may be caused by rapid changes in temperature and hence 
in volume of the contact-surfaces. With fourteen small cups 
it oceurred quite frequently. 
Columbia College, June 10, 1878. 
SCIENTIFIC INTELLIGENCE. 
I. CHEMISTRY AND PuHrysics. 
1. On the Microphone of Hughes.—At the meeting of the 
ney some) on May 9th, Professor Huxley presented a paper 
E. Hughes of London, on the action of sonorous vibrations 
in varying the force of an electric current.* The results described 
were obtained in an attempt to investigate, by means of the tele- 
phone, the effect of sound vibrations on the electrical behavior of 
matter, Using a Daniell battery of three cells, with a telephone 
in circuit, the wire conductor was subjected to strain until it broke; 
ted even by sound w Ten or 
twenty nails piled up log-hut fashion, increased the effect, and a 
piece of steel watch chain worked very well. Still better results 
were bbtaiied by the Pigh8 of a metallic powder in a glass tube, the 
instrument in this fo: So sensitive as to reproduce articu: 
late speech, All finely divi ed conductors which do not readil 
oxidie as such as platinum, mercury and carbon, or still better od 
lized “carbon (willow charcoal heated to whiteness and plun 
into mercury) may be used for the purpose, a glass tube filled 
with pa substances, and provided with wires for insertion in a 
‘ = Roginmeting, xxv, 369, 384, May 10 and 17, 1878. Sci. Am. Suppl. v, 2024, 
une 8, 
