442 Doctor Clark to Professor Mitsckerlich, 



(Sn) Accordingly, the differences of constitution that ap- 

 pear in the foregoing formulas, between, on the one side, 

 barytes, and on the other the salts of soda formed from 

 the sulphate, and the manganate, and the oxymanganate of 

 the same acids, are precisely such as would occur between 

 the proto and per salts that these acids would respectively 

 produce, when combining with the protoxide and the per- 

 oxide of tin. Thus far then of discrepancy, there is none. 

 But, on comparing . „ 



The oxymanganate of barytes . . Ba Mn Mn 

 And the waterless sulphate of soda . So S* 

 disoreoancv appears; for here we are presented with two 

 SET inform 'and in the number of their ultimate 

 opponents, but having these components combined tog - 

 ther so as to form intermediate compounds quite unlike in 

 constitution. The base of the first salt contains one atom 

 of oxvgen-the base of the second, two atoms of oxygen 

 the acid of the first contains seven atoms of oxygen-the 

 acid of the second, * atoms of oxygen. One of two alter- 

 natives therefore, is forced on our adoption. Either le 

 aln nl-'the fo-oo ng formula for sulphate of soda, we must 

 Tssimtte thereto the one for o^angan^of ^es, or 

 retaining the formula for oxymanganate of ba ytes we 

 must assimilate thereto the one for sulphate of soda. Now, 

 2 we adopt either alternative? You shall judge, after 

 rnnsiderin°- the following attempt : 



I Raining the formula for the sulphate of soda and 

 adopting a corresponding one for the oxymanganate of ba- 

 les we must likewise alter the formula for oxymanganate 

 of soda; but the other formulas do not need to be altered 

 When thus modified, the list of the salts already given will 

 stand as follows : 



Sulphate of barytes . . . Ba S 

 v Manganate of barytes • . Ba Mn 

 Oxymanganate of barytes . Ba Mn 2 

 Sulphate of soda ... So S s 

 Manganate of soda • • * ?° ~ n * 

 Oxymanganate of soda . • So Mu 4 



