On Sulphur et of Barytes as a Manure. 125 



acts as a very powerful manure ; in confirmation of 

 which, it appears, that some soils in volcanic countries, 

 that contain considerable quantities of sulphur, are 

 very fertile ; the same soils, likewise give out sulphur- 

 eted hydrogen gas, and this gas which is given out in 

 large quantities by sulphuret of barytes, produces 

 much of the deep green in the vegetables to which it 

 is applied, as it is found that those plants which grow in 

 the dark, if surrounded with a small quantity of hydro- 

 gen gas, are changed from a white appearance to a 

 green. 



There is also reason to believe that the barytes may 

 have some agency in promoting vegetation, as in its 

 pure state it is exceedingly caustic, and when taken 

 into the stomach proves a violent poison, yet when 

 dissolved in the muriatic acid, has been given in some 

 obstinate diseases, with much advantage, particularly 

 the scrophula. 



