230 
POPULAR SCIENCE REVIEW. 
PHYSICS. 
Changes of Temperature produced by Mixing different Liquids. — MM. Bussy 
and Buignet, to whose united researches we have already directed attention 
in an earlier number of this Review, have presented a second memoir to the 
French Academy, on the above interesting phenomenon. They have arrived 
at the following conclusions : — 1. In all the cases under examination, with 
one sole exception, the calorific capacity of the mixture is a little superior 
to the mean capacity of the elements. 2. By a singular opposition, the 
liquids for which the increase of bulk is the most considerable are exactly 
those which develope most heat at the moment of their union, such as ether 
and chloroform, alcohol and water, sulphuric acid and water. Meanwhile, 
the only instance hitherto noticed of a diminution of bulk is the mixture of 
chloroform and sulphide of carbon, at the same time the decrease of tempera- 
ture taking place at the moment of the union. 3. Independently of the loss 
of heat resulting from the changes of volume, there exists a cause which 
produces alone an absorption of heat — an absorption which can be sometimes 
equal, and even superior, to the heat given out by the combination of the 
liquids. — Comptes Rendus, February 25. 
Frozen Aerated Waters. — Mr. Tomlinson, of King’s College, who is one of 
our most indefatigable students of Natural Philosophy, has written to our 
contemporary, the Chemical News, explaining the curious phenomena 
resulting from the freezing of water, saturated with carbonic acid. He 
gives the following account of one of his first experiments : — During the 
recent cold weather I impregnated with carbonic acid, distilled water con- 
tained in eight-ounce and other phials, which were then corked and exposed 
to the air at temperatures ranging between 23° and 30° F. The first action 
of the cold was to produce long needles of clear transparent ice, as thick 
as the little finger, occupying aboukthe centre of the bottle, in some cases 
parallel with the sides, in others at an angle thereto. The further action of 
the cold was to enclose these transparent crystals in opaque ice, to thrust 
out the cork and break the bottle. In one case the bottom of the bottle was 
forced out ; in others the sides were cracked, and the cracks ran in lines from 
top to bottom, nearly parallel with the long axis of the bottle. Opaque ice 
filled the neck, and even overflowed, so that the ejection of the cork, the 
fracture of the bottle, and the overflow, of the ice, were simultaneous 
acts. 
New Form of Telegraphy . — An invention for the transmission of despatches 
by an automatic electro-chemical method has been devised by MM. 
Yavin and Fribourg. Its object is to utilise all the velocity of the current 
on telegraphic lines. The Abb6 Moigno, who has called attention to it in 
England, gives the following description of it : — It consists in the distribu- 
tion of the current through as many small wires, very short and isolated, as 
there are signals to be transmitted, all the. while only employing one wire 
on the main line. Each of these small isolated wires communicates, on the 
one hand, with a metallic plate, of a particular form, fixed in gutta-percha ; 
and, on the other, with a metallic division of a disc, which is also formed of 
an insulating substance. A group of eleven of those small laminae form a 
