.Department of CliemicaLResearch. 405 



the magnitudes of the atomic weights of the substances. "4th. 

 A general similarity of form, sufficient to show a graduated 

 degree of likeness. And 5th. A sufficient degree of difference 

 of form to characterize each individual substance. 



2. Curves o/HCl, HBr, and HI. 



a. Weak Solutions. 



Each acid was pure and colourless. The solutions were of 

 the same range of degrees of strength as those of the halogens, 

 in order to compare the effects of the two groups of sub- 

 stances ; and the curves are all drawn on the scale of magnitude 

 in each direction as those of the halogens. 



Fig. 2. 

 Curve of HC1 at 10° C.— TTmA: Solution. 



Fig. 3. 

 Curves of HBr and HI at 16° C- 



Weak Solution* 



HBr. 





