300 



Mr. Robert Mallet stated that about sixteen years since a 

 gentleman named Talbot called on him, and mentioned the fact 

 that sulphur burned in air produced both sulphuric and sul- 

 phurous acids, which he proposed to take advantage of in a 

 new mode of manufacturing the sulphuric acid of commerce. 

 In conjunction with this gentleman, Mr. Mallet expended 

 a good deal of money in experiments as to the feasibility of 

 the proposed method. The apparatus, briefly, consisted in a 

 chamber in which sulphur could be burned at as high a tem- 

 perature as was consistent with the non- volatilization of much 

 of it ; this communicated with the usual lead vitriol chamber 

 by a large tube, dipping a little under the surface of the water 

 therein. By means of a powerful air-pump, or fan, a partial va- 

 cuum was now produced in the vitriol chamber, which caused 

 a draught through the chamber in which the sulphur was 

 burned, the gases from which, bubbling up through the water 

 in the vitriol chamber, were in part condensed in the water. 



Abundance of a sour liquor was obtained ; but it was 

 found that, under the best possible conditions,"the amount of 

 sulphuric acid formed was so very small in proportion to that 

 of the vast volume of sulphurous acid generated, and which 

 was all wasted, that the process was valueless. 



The higher the temperature at which the sulphur was 

 burned, the greater was the proportion of sulphuric acid 

 formed ; but the limit to this was found to be such a draught 

 through the apparatus as would blow out the feeble flame of 

 the burning sulphur ; and at this point the per centage of sul- 

 phuric acid was so small that Mr. R. Mallet had satisfied him- 

 self the process could not be advantageously adopted. The 

 communication of Professor Davy was valuable, as placing 

 upon record (he believed for the first time) a fact theoretically 

 passed over or misstated in chemical authors, but was not 

 likely to lead to a manufacturing improvement. 



