April 2^, 1878] 



NATURE 



511 



end of a small battery ; a wire was adjusted near to, but 

 not touching, the platinum strip ; this wire led to the 

 receiving instrument, and thence back to the other pole 

 of the battery. On speaking into the conical orifice in 

 the bung the membrane was thrown into vibration, and 



the attached metal strip coming into contact with the 

 adjoining wire, momentarily completed the electric cir- 

 cuit. The vibrations of the membrane thus sent a 

 corresponding series of intermittent currents into the 

 receiver, which, in the first instance consisted simply of 



Fig. 3. — Sketch of improved form of transmitter made by Reis in his telephonic experiment (1862). 



a knitting needle surrounded by a coil of wire, and placed 

 on a violin to serve as a sound-board. Though Reis after- 

 wards considerably improved upon his earlier instru- 

 ments, the improvements do not seem generally known, 

 and the arrangement just described is substantially that 

 usually constructed and figured as Reis's telephone (see 

 (Figs. I and 2.) 



In Dingler's Polytechnisches Journal^ vol. 169 (1863), p. 

 29, is a report on Reis's improvedtelephone by Legat, inspec- 

 tor of telegraphs in Cassel, &c. This report was originally 

 printed in they<?«r«rt:/of theEast German Telegraph Com- 

 pany for 1862. Considerable modifications are here shown 

 in both transmitter and receiver . The membrane is formed 

 of a collodion film and is not loaded with any metal 



Fig. 4.— Sketch of improved form of receiver made by Reis m his telephonic experiments (1862). 



contact-breaker. A light S -shaped arm, supported a little 

 above its centre, so as to move freely in a vertical plane, 

 abuts at the lower end against the membrane, and at the 

 upper against the contact pin (Fig. 3). The circuit is com- 

 pleted through the cross-piece which supports the S-shaped 

 lever ; the least outward motion of the membrane would 

 thus break the contact, and in this way very feeble vibra- 



tions were able to be transmitted. The receiver consisted 

 of, practically, a horse-shoe magnet fixed horizontally on 

 a sound board ; the movements of a light iron keeper, 

 adjustible by a spring before the poles of the magnet, repro- 

 duced the original sounds (Fig. 4). Here it will be noticed 

 a molar motion of the iron has replaced the molecukar 

 motion first employed. A much louder sound is thus 



