

ANALYSIS OF SOILS. Q$ 



The quantity of calcareous earth is however very various, 

 and in fome cafes exceedingly fmall. A very fertile corn foil 

 from Ormiflon in Eaft Lothian afforded me in an hundred 

 parts, only eleven parts of mild calcareous earth ; it con- 

 tained twenty-five parts of filicious fand ; the finely divided 

 clay amounted to forty-five parts. It loft nine in decompofed 

 animal and vegetable matter, and four in water, and afforded 

 indications of a fmall quantity of phofphate of lime. 



This foil was of a very fine texture/ and contained very few 

 Hones or vegetable fibres. It is not unlikely that its fertility 

 was in ibrtre meafure connecled'with the phofphate; for this 

 fubftance is found in wheat, oats, and barley, and may be a 

 part of their food. 



A foil from the low lands of Somerfetfhire, celebrated for 

 producing excellent crops of wheat and beans without manure, 

 I found to confift of one-nintli of fand, chiefly filicious, and 

 eight-ninths of calcareous marie tinged with iron, and contain- 

 ing about five parts in the hundred of vegetable matter. I 

 could not dete6t in it any phofphate or fulphate of lime, fo 

 that its fertility muft have depended principally upon its 

 power of attracting principles of vegetable nourifhment from 

 water and theatmofphere *. 



Mr, Tillet, in fome experiments made on the compofition 

 of foils at Paris, found that a foil compofed of three-eighths 

 of clay, two-eighths of river fand, and three*eighths of the" 

 parings of Jimeftone, was very proper for wheat. 



XIX. Of the Compofition of Soils proper for bulbous Roott 

 and for Trees. 



In general, bulbous roots require a foil much more fandy, Soils proper for- 

 and lefs abforbent than the grafTes. A' very good potatoe foiI,' bulbous roots 

 from Varfel in Cornwall, afforded me feven-eighths of filicious 

 fand ; and its abforbent power was lo fmall, that one hundred 

 parts loft only two by drying at 400 Fahrenheit. 



Plants and frees, the roots of which are fibrous and hard, 

 and capable of penetrating deep into the earth, will vegetate 

 to advantage in almoft all common foils, which are moderately 

 dry, and which do not contain a very great excels of vege* 

 table matter. 



* This foil was fentvto me by T. Poole, Efq. of Nether Stowey, 

 It is near the opening of the river Parret into the Eritifh Channel j 

 but, I am told, is never overflowed, 



I found 



