CHEMICAL CHANGES DURING DECOMPOSITION. 



511 



analyses of the fresh diabase and the decomposed rock are given in columns 

 1 and 2. Supposing the alumina to have remained constant, the losses of 

 the other constituents are as given in column 3. 



Table V. — Analyses of fresh and altered diabase. a 



Survey, vol. 19, 1892, p. 357. 



i>S0 3 calculated from BaO found, as this latter probably exists as BaS0 4 . 

 c A1 2 3 is probably a little high, owing to alkali retained by titanic acid. 



