124 On Sulphur et ofBarytes as a Manure, 



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that the corn to which the sulphuret was applied, was 

 not disturbed by the ants or any other insect. 



I think sulphuret of barytes is the most powerful 

 manure hitherto discovered, and wish others to make 

 experiment with it : sulphat of barytes is the heaviest 

 of the stones, metallic stones excepted ; rather whiter 

 and harder than plaster of Paris ; roughly crystallized, 

 of no determinate form. Any person finding such a 

 mineral, can decompose some of it, and form a sulphu- 

 ret in the following manner ; powder it with about an 

 eighth of its weight of charcoal, put the powder into a 

 tobacco pipe and calcine it in a common fire, by keep- 

 ing it in a white heat for about a quarter of an hour, 

 exciting the fire with a pair of hand bellows. 



What the food of vegetables is, appears as yet some- 

 what doubtful, but the most probable conclusion is, 

 that, it consists of carbon, hydrogen and oxygen va- 

 riously combined, but principally of the two first : now 

 the sulphuret of barytes gives out great quantities of 

 hydrogen, combined with a small quantity of sulphur : 

 and as sulphurets are powerful solvents of carbon, 

 and indeed the only true solvents of that substance, 

 yet discovered, the sulphuret dissolves the carton in 

 the ground, thus we have the two principal ingredients 

 in the food of plants, prepared for their nourishment, 

 the oxygen being easily found in abundance, either in 

 the air or water. 



In calcining the sulphat of barytes and carbon, the 

 carbon unites with the oxygen of the vitriolic acid and 

 flies off, and sulphur is produced in large quantities, 

 and in a state very soluble in water, in which state it 



