6G Mr. Horapath on Elastic Fluids. 



decided by exjjerinient. According to his conclusions, die 

 march of an air tiiermometer is a correct indicator of the in- 

 crease of caloric ; and according to my theory the said march 

 is proportional to the difference of the squares of the true tem- 

 peratures. If therefore equal weights of any two bodies were 

 mixed at the Falir. temperatures 32^ and 212°, by his theory 

 the resulting temperature should be 122", the arithmetical 



mean; and by mine 118i°= ['^^'^'^^ t/^T^':)" -^.^J. 



With a greater interval of temperature, a greater difference 

 would exist. Now as far as experiments go on this subject, 

 they are unequivocally in my favour. Every philosopher 

 Avho lias tried such an experiment has, I believe, found 

 the resulting temperature beneath the arithmetical mean. 

 Even Crawford, who made experiments in a manner the most 

 unaccountable for any one who had hopes of success, found 

 his results less than M. Laplace's theory woidd give; and by 

 the only two of De Luc's experiments that I have yet seen, 

 there are variations fiom M. Laplace's theory of 3° and 2^° in 

 defect, and from mine of only f ° and Jy° in excess. I have 

 also made some experiments on this subject myself, which 

 accord with the conclusions I have drawn equally as well as 

 De Luc's ; but in consequence of being deprived of the means 

 of decidino- the value of some corrections through a material 

 accident to my apparatus, I have not yet been able to put them 

 in a condition for publication. 



It were much to be wished that some decisive experiments 

 of this kind were undertaken by those who have proper appa- 

 ratus and opportunities. A determination of the true quantity 

 of deflection from the arithmetical mean of equal weights of 

 the same body mixed at unequal temperatures, would at once 

 settle the grand point respecting the real indications of thermo- 

 meters ; and consequently establish laws of the highest inipoi'- 

 tance in science. 



Cranford, July 19th 1823. J. Hekapath. 



XIII. Notices respect i7ig New Books. 



Recentlij jmblishcd. 



T^HE First Part of the Transactions of the Philosophical 



-■- Society for 18^3 has just appeared, and the following are 



its contents : 



The Croonian Lecture. Microscopical Observations on the 

 Suspension of the muscular Motions of the Vibrio Tritici. By 

 Francis Bauer, Esq. — On Metallic Titanium. By W. IT. 

 WoUaston, M.D. — On the Difference of Structure between 



the 



