'36G AcnicuLTunAL museum. 



upon soils and plants, to prpnii^e a short Irart cxplana-- 

 tovy of the fuMdamcntal laws of naturo, which are thu 

 primaiy cause of the changes and variety of so'Is, with- 

 out a knowlerlge of which, as full and clear a compre- 

 hension a-^ the subject will admit, at this time, could not 

 be had. We have also set bounds to soine of the prin- 

 cipal regions of soil, and 'jhowa that the surface, ele- 

 vation, and position grnci ally, to say nothing of other 

 causes, form material diUcrenccs in soil and protlu'-e, 

 suflicicntly distinct characteristic traits ou which to 

 bottom a system of classificatiop. 



I will now, according to the promise made in my first 

 liiimbcr, proceed to a more minute and spccitic des- 

 cription! of the soils most comiionly found, shewing the 

 analysis and composition of fertile soil, and the food of 

 plants, taken a'most wholly from Kirwan and tiie most 

 approved chymical writers. At the same time 1 will 

 shew the general position of the kinds of soils descri- 

 bed in the regions heretofore spoken of. Preparatorj* 

 to this investigation, it is necessary to settle accurately 

 the meaning of the names and distinctions of soils, ele- 

 mentary earths and manures, intended to he used ; as the 

 terms used by Agricultural writers are frequently very 

 vague, and have different meanings in different places 

 and countries. 



I shall adopt the distinctions and denominations given 

 in the first chapter of Mr. Kirvvan's treatise on manures 

 and soils, as follows: 



T I'ld considered as the basis of vegetation is called 



b <ds consist of different combinations of two or more 

 of the four primitive earths, namely, the calcareous, 

 (which sometimes he calls mild calx ) magnesia, argill, 

 and the silicious. For a more accurate description of 

 these I must refer to books of mineralogy, and 

 shall only remark that by calcareous earths, are meant 

 chalk, and all stones that burn to lime. They are easily 



