1821.] Atomic Weight of various Metals and Acids. 125 



products, we shall obtain very little short of 19 cubic iuches of 



oxygen gas. ^ 



It cannot be doubted that protoxide of antimony, which we 

 obtain by dissolving this metal in muriatic acid, and throwing it 

 down by water, is a compound of one atom antimony + one 

 atom oxygen. Of consequence, its weight must be 6-5. This 

 oxide has a grey colour, and is rather dark. The white oxide 

 must be a combination of one atom of protoxide and one atom 

 of peroxide; for 



1 atom protoxide = 6-5 



1 atom peroxide = 7-5 



2)14-0 



7-0 

 = 1 atom of white oxide. 



The composition of the different oxides of antimony may be 

 thus stated : 



Antimony. Oxygen. 



Protoxide 5*5 + 1-0 



White oxide 5-5 + 1-5 



Yellow oxide 5-5 + 2-0 



The protoxide of antimony dissolves in acids, and, therefore, 

 possesses the characters of a base. I have never been able, 

 however, to neutralize any acid by means of it. From the expe- 

 riments of Berzeluis, it appears that the peroxide combines with 

 bases, and, therefore, is entitled to the name of acid. He has 

 given it the name of antimonic acid. He gives the same account 

 of the white oxide of antimony. I do not mean to deny the 

 accuracy of his experiments, though I have not been so success- 

 ful in my attempts to repeat the in as I could wish. I did not 

 succeed in obtaining a definite compound of the white oxide of 

 antimony, though 1 have some reasons for suspecting that it is 

 this oxide that enters into the composition of tartar emetic. 



The red substance formerly distinguished by the name of 

 kermes mineral is, I find, a hydrosulphuret of antimony composed 

 of one atom sulphuretted hydrogen and one atom protoxide of 

 antimony. 



1 atom of sulphuretted hydrogen. . = 2-125 

 1 atom protoxide of antimony .... = 6*5 



8-625 



It is, therefore, composed of 2-125 of sulphuretted hydrogen 

 + 6-5 protoxide of antimony ; so that 100 parts of it con- 

 sist of 



