THE SOIL. 313 



5. SANDY LOAM deposits from 60 to 90 per cent, of sand. 



6. SANDY SOIL contains no more than 10 per cent, of pure 

 clay. 



To analyze the above soils with a view to classifying them. 



RULE. Weigh a portion of the soil and spread it thinly 

 on writing paper, and dry it for an hour or two in an oven, 

 the heat of which is not great enough to discolor the paper 

 the loss of weight is the quantity of water it contained. 



Weigh and then boil another equal portion, and when 

 thoroughly incorporated with the water, pour it into a vessel, 

 and allow the sandy parts to deposit until the fine clay is 

 also beginning to settle ; then pour off the water, collect the 

 sand, dry as before, and again weigh, which will give the 

 per cent, of sand it contained. 



The above classification and analysis of soils have refer- 

 ence only to the water, clay, and sand which they contain, 

 while lime is also an important constituent, of which they 

 are rarely entirely destitute. This gives rise to a further 

 classification. 



7. MARLY SOIL is one in which the proportion of lime is 

 more than 5, and not over 20 per cent, of the whole weight. 



8. CALCAREOUS SOIL, in which the lime exceeds 20 per 

 cent. 



To analyze marly and calcareous soils, with a view to 

 their classification as above. 



RULE. Mix 100 grains of the dry soil with half a pint 



14 



