SCIENTIFIC SUMMARY. 
105 
are circular, or of their homologous diameters if they have any other form. 
— Comptes-Rendus, Nov. 2 and 30. 
Mode of Conduction of Heat hy Bodies. — M. Magnus has read an important 
paper before the Berlin Academy of Sciences, furnishing the proof of the 
proposition already asserted by him, that heat is propagated in bodies by 
transverse vibrations like light, or, at the very least, that transverse vibra- 
tions play a most important part in the transmission. M. Magnus had 
shown in a previous memoir that heat radiating at an angle from a red-hot 
and polished plate of platinum proceeds both from its surface and from its 
interior, this being a consequence of the polarisation of the heat which 
radiates from this surface. The plane of polarisation has the same situation 
as that of light refracted at a certain angle. It must therefore be admitted 
that a portion at least of the rays is refracted at the surface ; but for this re- 
fraction to be possible the heat must come from the interior of the platinum. 
This polarisation is effected according to the same laws as those of light, 
and therefore the interior propagation must be performed, like that of light, 
by transverse oscillations. M. Magnus had asserted his proposition on the 
grounds that the motion called heat cannot be double, and that its pro- 
pagation when made through air, through a vacuum, or through any other 
diathermanous substance by means of transverse oscillations, must be of 
the same kind as in the interior of athermanous bodies which we call 
conductors. But this conclusion was not a certain one j the only point of 
it made out was that heat was polarisable. But if it is proved that heat 
radiating at an angle at any temperature whatever, and therefore at a 
very low one, is also polarised in part, it will be established, even for opaque 
bodies, that the heat radiated by them proceeds partly from their interior, 
and is propagated in them by transverse oscillations. It would then be 
proved, M. Magnus believes, that the conductibility of heat, or its propaga- 
tion in athermanous bodies, rests on transverse oscillations. In his present 
communication M. Magnus has furnished this part of the proof required, by 
experiments which establish that bodies heated to 100° radiate polarised 
heat. — I! Institute Nov. 18. 
A nev) Exciting Liquid for Galmnic Batteries. — A French chemist sug- 
gests the following compound liquid for electro-galvanic batteries : Twenty 
parts of protosulphate of iron in thirty- six parts of water, seven parts of sul- 
phuric acid, and one part of nitric acid. He declares this to be the most 
powerful and exciting liquid, attacking iron, zinc, and other metals, without 
any evolution of hydrogen or binoxide of nitrogen. — Nev) York Medical 
Record, Dec. 1. 
A neio way of Detecting the Discordance of Diapasons. — A means of dis- 
covering a want of accordance between two diapasons has been pointed out 
by M. Lissajous, in a note to the French Academy. They are to be made 
to vibrate, and then put in connexion wdth a bath of mercury. When they 
are in accordance the surface of the mercury remains perfectly calm. If 
there is discord between them waves are produced on the surface directed 
towards that instrument of which the vibrations are the less in number. — 
Elnstitut, Dec. 16. 
