Mathematics to Chemistry, 



283 



chloric acid, which Dr. Thomson says requires farther 

 investigation, and besides a small discrepancy in oil of 

 turpentine, a substance not easily obtained in a perfect 

 state; so that the rule appears to be without exception. 

 The calculations are evidently easy and simple ; all that is 

 required, is to add together the atomic weights of the simple 

 elements contained in the compound, and multiply the sum 

 by '0694 the specific gravity of hydrogen, which gives the 

 specific gravity required, when the elements combine in 

 single'groups, and half that product is the specific gravity, 

 when the combination is in double groups : but when there 

 is only a cohesive combination, the same product is to be 

 divided by the number of elements which combine. 



These three are the only varieties of chemical combination 

 which can occur. 



Fig. 2. 



ri^s. 





.'»•?. 



Fig. 5. 



Fig. 6. 



A cohesive combination is represented in fig. 3, one in 

 single groups in fig. 4, and one in double groups in fig. 5, 



