[ '58 ] 



glafs or fand were contained in pots that had no hole in the 

 bottom through which other nutritive matter might be con- 

 veyed. It is certain, at leaft from common experience, that 

 neither grafles nor corn grow well either in mere clay, fand or 

 chalk, and that in vegetables that grow moft vigoroufly, and in 

 a proper foil, three or four of the fimple earths are found. Mr. 

 Bergman, on the other hand, affures us he extraded the four 

 earths, the filiceous, argillaceous, calcareous and muriatic, in dif- 

 ferent proportions from the different forts of corn *. Mr. 

 Ruckert, who has analyzed moft fpecies of corn and grafles, found 

 alfo the four above-mentioned earths in various proportions in 

 all of them. Of his analyfis I fhall here give a fpecimen, com- 

 prehending however the calcareous and muriatic in the fame 

 column, as this laft fcarcely deferves particular notice: 



* 5 Bergman, 94, 98. SchoefFcr Worles, fee. 172. 



