FABRICATION OF SULPHURIC ACIJ*. 43 



When we attentively observe the burning of the ordinary In the ordinary 

 mixture of sulphur, nitrate of potash, and wet clay, we oxid^evolved, 

 perceive, that the nitric acid is not completely decomposed, 

 and that a great deal of nitrous acid gas passes into the leaden 

 chamber with the sulphurous acid. Its colour renders it 

 very visible, and it is a fact that cannot be questioned. 



This observation affords a key to the true theory ; and in This the key t» 

 following up its consequences we find the production of sul- 

 phuric acid clearly explained. 



We are certain, that the combustion extricates a mixture Recital of the- 

 of nitrous acid gas, and sulphurous acid, with water in va- 

 pour, and nitrogen gas from the atmospheric air. We may 

 suppose too, that a portion of oxigen has escaped the ac- 

 tion of the sulphur. This supposition, which has nothing 

 in it that is not extremely probable, is the only thing on 

 which any doubt can be entertained. Now, from an ex- Nitric oxide 

 periment made purposely to ascertain this, the sulphurous p h ur0 us add 

 acid gas and nitrous acid gas cannot exist in contact, with- into sulphuric. 

 out the latter being decomposed, and converting the former 

 into sulphuric acid ; this then will take place, when such a 

 mixture of the two gases takes place in the leaden chamber. 

 Being then at a distance from the place of the combustion, 

 this mixture finds a lower temperature, which occasions the 

 condensation of part of the vapour ; the rain thus formed 

 carries with it the sulphuric acid produced, and affords a 

 vacuum to the different substances that remain ; these pre- 

 cipitate themselves into it in eddies, and present to each 

 other a thousand points of contact that favour the action of 

 their affinities. 



After the first production of sulphuric acid, there remain The nitrous ox^ 

 nitrous oxide gas, sulphurous acid, atmospheric air deprived takeToxicen 6 

 of part of its oxigen. The nitrous oxide necessarily con- from the air, 

 verts itself into nitrous acid, which will be again decom- oxIdT and thT 

 posed to the profit of a second portion of sulphurous acid ; yields its oxi- 

 and this will go on till all the nitrous acid or atmospheric Serous acid 

 oxigen, or both, are exhausted. 



The first productions of sulphuric acid must be the most Th e sulphuric 

 copious and rapid, because the condensation of the aqueous mcst co „i 0us jy 

 vapour produces a great commotion in the mixture of the atn «t. 

 different gases; and because too the abundance of the ox- 

 igen 



