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with sulphur. I have also particularly directed my attention 

 to the agency of atmospheric air on burning sulphur, and a 

 number of the sulphurets ; and the action of oxygen gas on 

 sulphur under different circumstances. The time I have de- 

 voted to these inquiries, though considerable, has not been 

 suflBcient to complete them : but as I can only pursue the 

 subject at short intervals of leisure, I trust I shall be excused 

 for bringing before the Academy results, which, though im- 

 perfect, appear to me to be both novel and important. 



" Sulphuric acid, from its vast importance to our arts and 

 manufactures, has, from time to time (as is well known), en- 

 gagedmuch scientificattention. Some of the mostdistinguished 

 chemists of Europe have made it the subject of elaborate in- 

 quiry and investigation ; yet it is a remarkable fact, that they 

 appear tome to have overlooked themannerin which it is formed 

 under different circumstances ; and their authority, it is to be 

 feared, checked inquiry, and tended to confirm and perpetuate 

 error. It is a received opinion that sulphuric acid cannot be 

 made directly from its elements, sulphur and oxygen, but is pro- 

 duced by causing sulphurous acid to unite with an additional 

 equivalent of oxygen in contact with moisture or water. That 

 opinion, however, is the result of imperfect observation, and 

 is not founded in fact. Sulphuric acid may be made with fa- 

 cility from its elements, under different circumstances. Thus, 

 if we burn sulphur in atmospheric air at the lowest possible 

 temperature, in contact with glass, porcelain, metals, &c., 

 the products will be sulphurous and sulphuric acids. If we 

 burn sulphur in air at higher temperatures, in contact with 

 the same substances, the results will be similar, but the quan- 

 tity of sulphuric acid produced will be greater than would be 

 formed at lower degrees of heat. 



" Sulphurous acid is considered to be the sole product 

 arising from the combustion of sulphur in dry oxygen gas, 

 or atmospheric air. I am satisfied this is not the fact. I have 

 repeatedly burned sulphur in oxygen gas under different cir- 



