32 Mr Sankey on the action of Caloric 



will be modified according as the number of strata is even or 

 odd, or as the one or the other of the alternate strata is the 

 lowest. From the preceding observations, it is evident that 

 the arrangement of the minute particles must considerably in- 

 fluence the effects of caloric, as manifested in the rise of fluids. 

 A knowledge of these arrangements of the atoms will proVjably 

 be much facilitated by an attention to the forms of the crys- 

 tals, and the mode of the transmission of light through the 

 fluid. The figure of the atom has here been assumed to be 

 a sphere, which will answer sufficiently for calculations made 

 in regard to such minute bodies. 



The size of these particles is also an interesting subject 

 of research, the investigation of which might perhaps be 

 aided by the comparison of different substances, in respect 

 of the expansive power which caloric is found to exert upon 

 them at the same and different temperatures. In conduct- 

 ing such inquiries, however, we should take into considera- 

 tion that the specific gravities of bodies do not give us the 

 specific weights of the ultimate atoms, but only of apparent- 

 ly equal bulks of matter. For instance, if we have two equal 

 cubes of two substances, the weight of either is equal to the 

 weight of its minute atom multiplied into the number of 

 these atoms, consequently, calling the absolute weights of 

 these equal bulks, S, 2, the weights of the ultimate atoms 

 W, w, the number of atoms in each row of each stratum 

 iV, n, then S = WN^, and ^ = w n\ Now, calling the 

 diameter of the ultimate atoms of the two bodies P, p, 

 and m the modulus of gravity, then W = m P^, and 

 w = m p^, therefore S =: m P^ JV^, and 2 = m p^ w^, •/ 



/Ss= map Nj and j.i sz mi p n, and — - =P N, also-^ =p n. 



m^ m^ 



Calling now any side of any square surface of these equal 

 cubes a, and T, t, the distance between the particles, then a 

 = N (P-{- T^-^T; a\soa = n (p -{-t)--^t :. a -^N P z=z 

 (N— 1) Ty and a — w;?, = (w — 1) ^ /. substituting for NP 



and np their values as above, a j- = (N — 1) T, and 



trt* 



