312 



PROCEEDINGS OF THE AMERICAN ACADEMY. 



hand, manganese is undoubtedly originally in a very compressed state, 

 its large self-affinity being shown by its exceedingly high melting point ; 

 hence the contraction to be observed on forming the hydroxide is not as 

 large as one would otherwise have expected. f Many other irregularities 

 in the approximate parallelism of these four sets of data can be explained 

 on the basis of the principles explained in the present paper and those 

 preceding it, but until more exact figures are at hand, a closer compari- 

 son is not worth while. 



* Grundriss, 281 (1899). 



t Richards, These Proceedings, 37, 11 (1901). 



