Kobkrtson. — Latent Heats of Fusion. 



505 



A represents Aw/Tv ^ . 



B represents percentage difference from mean. 

 C represents Crompton's 1895 relation, Aw/Tu. 

 D represents percentage difference from mean. 

 E represents Crompton's 1897 relation, 10xtt^/T. 



Thus the relationship Aw/TV^ is much the most satis- 

 factory, the mean deviation being +8 per cent., a deviation 

 of the same order as observed in the law of Dulong and Petit. 

 But it must be borne in mind that the latent heat of fusion is 

 one of the most difficult physical constants to determine, and 

 that if the densities were taken at some corresponding tempera- 

 tures, such as at the melting-points, the results would perhaps 

 bf even closer. There is a large number of wide deviations 

 in Crompton's first relation, while in the case of bromine and 

 iodine it was assumed that the valencies were 3, which 

 assumption is decidedly open to criticism. 



In the case of compounds, if A is replaced by M (mole- 

 cular weight) the values for Mw/TvM are also found to be 



constant. The following are the data for those substances 

 whose densitv in the solid state I have been able to find. 

 The values for lead-bromide and silver-chloride are from the 

 results of Weber, who deduced them from electrical experi- 

 ments. The latent heats of antimony chloride and bromide 

 and the bromides of tin and arsenic have been calculated 

 from their depression constants. The remaining numbers are 

 taken from Crompton's paper. 



Table IV. 

 A. Inorganic Compounds. 



