LARD AND LARD ADULTERATIONS. 435 



Although it appears to mo that the formula as follows would be more correct 



Do Do' 



(t 

 or, still better: 



Do - Do' 



Great confusion exists iu chemical literature in the expression of specific gravities. 

 I have referred all my results to water at 4 C., believing that eventually all specific 

 gravities will be stated in these terms, as is the custom in continental Europe. 



The absolute densities are calculated from the formula A = S -j-/c, in which 



A = Co-efficient of absolute expansion. 



S = Co-efficient of apparent expansion in glass. 



K = Co-efficient of cubical expansion of glass =.000025. 



The weights -were not reduced to a vacuum, and no correction was made for the 

 thread of mercury projecting above the bulb. The specific gravities of the different 

 samples at various temperatures are also given in the the last columns of the table, 

 these having been calculated by means of the co-efficients of expansion. 



