Scientific Intelligence. 113 
4 SCIENTIFIC INTELLIGENCE. 
I. Puysics, 
: 1. On the Expansion of certain substances by Cold ; by W. 
_ Macquorn RaNnkINE, Civil Engineer, F.R.SS., Lond. and Edinb. Ge. 
(Phil. Mag., [4], viii, 857.) —During the discussion which followed the 
reading of the Rev. Prof. Powell’s Report on Radiant Heat, at the 
meeting of the British Association i in Ia54, it appears, from the report 
the means reconciling the dynamical theory of heat with the 
fact of the expansion of water, antimony, cast iron, wilis Lectin ls 
cold, at and near their freezing points; and t me 
servations were made in reply by Professor Powell and Prof. “Williams, 
i) 
The question is one’of much importance, and oe for the onion 
_ of every one who has been instrumental in maintaining the gills 
_ theory of heat. Having been prevented by test from attending the 
__ meeting of the Association, I beg leave to offer t ing remarks 
pa 
The theory of thermo-dynamics, strictly speaking, is a system of 
ey eed all of which are deducible from a following tis laws : 
al p 
q airy of heat which disap- 
els otaal’ change (dV) of the vol- 
sive pressure (P) with temperature at constant volume; that is 
d 
to say, tT, 0. 
When this product is Basile it represents heat which disappears ; 
when negative, heat w 
Neither of those eng indicates ‘any particular relation between the 
pressure, iolume, and temperature of a given mass of a given sub- 
stance as more probable than any other. ‘Ibe nature of such relations 
must be dcieivnigen for each substance by pseedainale before the two 
ed to 
f matter (such as the hypothesis of molecular vortices), so as to de- 
duce the two laws of thermo-dynamics from those of ordinary mechan- 
ics, that hypothesis must lead to many consequences besides those two 
laws ; and it is necessary that those consequences i gould not be incon- 
istent with any of the phenomena of the relations between the tem- 
f those consequences was ted by Mr. James Thomson, and 
“Ac antsy @ by. Professor William Ties at a time when the e theory A ther- 
10-dynamics was in a yery imperfect state, viz. that the freezing-point of water is 
lowered by pressure 
Szconp SERIEs, Vol XX, No. 58.— July, 1855, 15 
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