AGRICULTURE WITH CHEMISTRY. 



deprived of the water of chrystallization, and brought to 



an equal degree of dryness, the quantity of calcareous 

 matter and magnesia in each may be ascertained by BERG- 

 MAN'S or KIRWAN-S tables of the proportion of acid, al- 

 kali, earth, and water contained in different neutral salts. 

 To those who are not provided with such tables, it may 

 suffice to say, that 



Acid Cakar. Matter Water 

 TOO parts of gypsum contain 48 34 18 



Acid Magnesia Water 



100 parts of Epsom salt contain 33 19 48 



As both clay and sand, in different proportions con- 

 stituting either a clayey or sandy soil, are distinguishable 

 by the sight and touch, there is no occasion for giving 

 any chemical test, to prove their presence. The pro- 

 portion of the coarser parts of siliceous matter or sand, 

 in soils or mould, may be ascertained by washing. 



The presence of vegetable or carbonaceous matter in sur- 

 face mould, when in any considerable proportion, is ap- 

 parent, either from its black colour, or from the vege- 



u 2 table 



