[ 1^9 ] 



Silex, from 4362 to 4475 

 Argill — 509 — 793 



Calx — 283 — 679 



He alfo found it to contain a great deal of air (about 19 grains) 

 of which ^ was fixed, and the remainder heavy inflammable air j 

 but no volatile alkali. 



The weight of a cubic foot of this foil does not appear, nor 

 is its fpecific gravity given ; hence neither its texture, nor the 

 quantity of each ingredient, can be diredly afcertained ; yet from 

 the neceflity of its being in fome degree open, and the weights 

 of good foil found by Mr. Fabroni *, I conclude its fpecific 

 gravity cannot exceed 1,58 ; then a cubic foot of it fhould weigh 

 about i2olb. troy, or 100 avoirdupois. 



In lefs fertile foils Mr. Giobert found the proportions of 



Silex from 48 to 80 

 Argill — '7 — 22 

 Calx — 6 — II 



Hence the troy pound contained of 



Silex from 2716 to 4528 



Argill — 396 — 1245 



Calx — 339 — 622 



allowing 100 grains for moifture, as either the calx or argill exceeds 

 the proportions in more fertile lands. 



VoL.V. Y The 



♦ 8 Young's Annals, 174. 



