42 TABRICATION OF SULPHURIC ACl©. 



acid gas produced into sulphuric acid ; but the contrary to 

 this is easily proved. The quantities of the elements that 

 concur in this operation, or result from it, are not known 

 with precision ; yet those we shall assume may be considered 

 as sufficiently near the truth to refute the second hypothesis. 



Jfaewn by the Nitrate of potash contains about 0.30 of nitric acid; 



proportions of wn ich ac id according to Davy, contains 0.70 of oxigen. 



Tfceir principles. ,,..,?, - 



In this nitrate therefore there are 0.70-^0.30=0.21 of 



oxigen. In sulphurous acid there are about 0.59 of sul- 

 phur, and 0.41 of oxigen; and in sulphuric acid 0.52 of 

 sulphur, and 0.48 of oxigen. Now if we employ a very 

 large receiver, or long continuance in a small one into which 

 the air can enter, all the sulphur burnt with £ of its weight 

 of nitrate of potash will be converted into sulphuric acid. 

 Thus, if we operate with 90 parts of sulphur and 10 of 



nitrate of potash, we shall have - — — = 152 of sulphu- 

 rous acid, which will produce =173 of sulphuric 



acid, and consequently require 173—152=21 of oxigen. 

 But the 10 parts of nitrate of potash, employed in this 

 operation, could not give more than 2.1 of oxigen, or a 

 tenth of the quantity necessary to saturate the acid. Some 

 manufacturers carry the proportion of nitrate of potash to 

 the sulphur as far as 0.2 ; but in this case, which is the most 

 favourable to the hypothesis we controvert, the nitrate is 

 but || of what would suffice according to the proportions 

 admitted. The nitre therefore does not serve to produce 

 sulphuric acid, as has been supposed. If its oxigen be not 

 sufficient to convert the sulphurous acid into sulphuric, still 

 less can it suffice to saturate the sulphur with oxigen, with- 

 out the assistance of the atmospheric air ; and it is remark- 

 able, that the acid contained in the sulphate of potash, the 

 residuum of the combustion, contains more oxigen than the 

 nitrate could furnish. 



If any doubt of the solidity of this reasoning remain, 

 on account of the uncertainty of the proportions of the 

 substances operating, they will soon be dissipated, when 

 the perspicuousness of the new theory is contrasted with 

 these vague opinions. 



When 



