SCIENTIFIC SUMMARY. 
219 
duplication of G sharp, however, throws some doubt on the correctness of the 
scale . — Pall Mall Gazette , March 18. 
The Phonograph essentially consists of two parts, a recording instrument, 
and another for deciphering and reading aloud the record thus obtained. 
The former has a mouthpiece stopped at its inverse end by a metallic 
diaphragm carrying a point. In close approximation to the point, a metal 
cylinder covered with tinfoil is made to rotate in a spiral. The tinfoil being 
left unsupported behind by a spiral groove of similar pitch cut in the 
cylinder, is indented by the point with depressions corresponding to the 
vibrations of the metallic plate. The permanent record thus obtained re- 
quires deciphering, an end which is obtained by the other portion of the 
instrument. This consists of a similar diaphragm held in a tube on the 
opposite side of the cylinder, attached to another point pressed against the 
tracing by a delicate spring. The original vibrations are thus transferred to 
a second membrane, and reproduced in the form of sound. The machine 
has been exhibited before several London Scientific Societies with complete 
success. Mr. Preece brought it under the notice of the Physical Society on 
March 2. Two forms of the instrument were illustrated. In one, the 
receiving and emitting disks are distinct, one being of ferrotype iron, and 
the other of paper ; in the other, both functions are performed by one and 
the same disk of iron. In one, moreover, the drum is moved by hand ; in 
the other by a train of wheels and a descending weight, regulated by an 
adjustable pair of vanes. Sounds emitted by the paper disk appeared to be 
more distinct than those from the iron. Professor Fleeming Jenkin suggests 
that the Phonograph may be found of value in throwing light upon the 
nature of vowel-sounds, and confirming or correcting Helmholtz’s theory. 
A full detail of experiments made by him and Mr. Ewing on the subject is 
promised. 
Ice as an Electrolyte. — Messrs. Ayrton and Perry have forwarded to the 
Physical Society a second communication on Ice as an Electrolyte. In their 
former paper they described experiments proving that as the temperature of 
ice is allowed gradually to rise, the conductivity increases regularly, and that 
there is no sudden change in passing from the solid to the liquid state. They 
also roughly determined the specific inductive capacity of ice and water at 
— 13 0, 5 and + 8 0, 7 Cent., showing that at the latter temperature it is 2,240 
times as great as at the former; there being very little change in the 
capacity up to 0° Cent., nor after that point ; it was expected that a very 
great change must occur at the melting point. In their second paper 
approximate curves have been traced from — 12 0, 2 to + 5° Cent, by charging 
for 10 seconds, and then short-circuiting for 15 seconds. The change at the 
melting point, though quite as sudden as expected, on the whole realizes 
their anticipations. “ The important theory,” they remark, “ which Professor 
Clerk Maxwell has developed, by comparing the propagation of electro- 
magnetic disturbances through the ether with the propagation of light- 
vibration, has been illustrated only by paraffin, a non-conductor ; and he- 
lias not considered the propagation of electro-magnetic disturbances in a 
conducting medium. But according to a former paper on the “ Viscosity of 
Dielectrics,” no dielectric can be affirmed to be non-conducting, and the 
charging of any condenser whatever is always accompanied by absorption 
