AGRICULTURE WITH CHEMISTRY. 139 



plants ; thus rendering them unfit for the food of such 

 insects. The effecSls of soot are not confined to the de- 

 struilion of inserts alone ; for the resinous bituminous 

 oil, dissolved by the saline matters, promotes the growth 

 of plants in a very high degree, and by rapidly pushing 

 them to an advanced state of maturity, allows no time 

 for the ravages of inse»51:s on the young and tender roots 

 and leaves of plants, on which, in general, they princi- 

 pally feed. 



The quantity of soot that can be colle6led, is so incon- 

 siderable, in proportion to its uses, and the demand 

 tliere might be for it, were its powers more generally 

 known, that a method of procuring a greater supply of 

 this essential article, or of any substance that would pro- 

 duce similar good effecfls, is an objedt of very great im- 

 portance to Agriculture. This is to be accomplished by 

 different preparations, amongst which coal-tar is to be in- 

 cluded. The chemical analysis, and deieterious or poison- 

 ous effeds of coal-tar on insefts, prove its identity to soot ; 

 the only difference being, that of its containing less fuligi- 

 nous, or carbonaceous and earthy matters : in which re-' 

 spefls, as carbonaceous and earthy matters arc not soluble ' 



s 2 ill 



