[ I70 ] 



The fpecific gravity of thefe foils is not given, but it probably 

 exceeds or falls fhort of that of the more fertile foils. 



In Barren Soils. 



The proportions of Silex from 42 to 88 



Argil — 20 — 30 



Calx — 4 — 20 



Hence the troy pound contained, allowing for water 120 grains, 

 Silex from 2368 to 4963 

 Argil — 1 1 28 — 1692- 

 Calx — 225 — 620 



The fpecific gravity of thefe foils is not given, but it pro- 

 bably is either much above or much beloxv that of the former, 

 as they are either too clofe or too open. Mr. Fabroni found that 

 of barren fandy land 2,21. 



Note alfo, that if the proportion of water be different from 

 that here fuppofed, the contents of the troy pound will alfo be 

 different, but may eafily be rectified. 



Analyfis of a fertile Soil, where the fall of Rain is 24 Inches. 



Mr. Bergman found th:;' a fertile foil, fituated on a plain, 

 where the yearly fall of rain amounts to 15 Swedifh (that is 23,9 

 Englifh inches) contained four parts clay, three of filiceous fand, 



two. 



