28 On the Analysis of Soils, 



stance, and may be principally resolved by heat into this 

 substance, volatile alkali, inflammable aeriform products, 

 snd carbonic acid ; il is principally found in lands that have 

 been latelv manured. 



Vegetable decomposing matter is likewise very various in 

 kind ;"it contains usually more carbonaceous substance than 

 animal matter, and differs from it in the results of its de- 

 composition principally in not producing volatile alkali ; 

 it forms a great proportion of all peats ; it abounds in rich 

 mould, and is found in larger or smaller quantities in all 

 lands. 



The saline compounds found in soils are very few, and 

 in quantities so small, that they are rarely to be discovered. 

 They are principally muriate of soda (common salt), sul- 

 phate of magnesia (Epsom salt), and muriate and sulphate 

 of potash, nitrate of lime, and the mild alkalies. 



The oxide of iron is the same with the rust produced by 

 exposing iron to the air and water ; it is found in all soils, 

 but is most abundant in yellow and red clays, and in yel- 

 low and red siliceous sands. 



A more minute account of these different substances 

 would be incompatible with the object of this paper. A 

 full description of their properties and agencies may be 

 found in the elementary books on chemistry, and particu- 

 larly in the Svstem of Chemistry by Dr. Thomson (2d ed.) ; 

 and in Henry's Epitome of Ciiemistry. 



III. Instruments required for the Analysis of Soils. 



The really important instruments required for the analysis 

 of soils are few, and but litile expensive. They are a ba- 

 lance capable of containing a quarter of a pound of com- 

 mon soil, and capable of turning when loaded with a grain; 

 a series of weights from a quarter of a pound troy to a grain ; 

 a wire sieve, sufficiently coar.se to admit a pepper-corn 

 through its apertures ; an Argand lamp and stand ; some 

 glass bottles ;' Hessian crucibles ; porcelain or queen's 

 ware evaporating basons; a Wedgcwood pestle and mortar ; 

 some filters mad'c of half a sheet of blotting-paper, folded 

 so as to contain a pint of liquid, and greased at the edges ; 

 a bone knife, and an apparatus for collecting and measuring 

 aeriform fluids. 



The chemical substances or reagents required for sepa- 

 rating the co;>slituent parts of the soil, are muriatic acid 

 (spirit of salt); sulphuric acid, pure volatile alkali dissolved 

 in water, solution of prussiate of potash, soap lye, solution 

 of carbonate of aumionia, of nuirlate of ammonia, solu- 

 tion 



