3*^ AGRICULTURAL ESSAYS. 



it is completely dry, and turn it over frequently, that it may be 

 ^ well mixed together. From the heap take exactly 4 ounces, 

 and pass it through a sieve, which will allow all the particles 

 of sand and gravel to escape, but hold back stones, small 

 fibrous roots, and decayed wood. WeigJi the two parts separate- 

 ly, and take a note of each. The stones and other bulky ma- 

 terials are then to be examined apart from the roots and wood. 

 If they are hard and rough to the touch, and scratch glass 

 easily, they are silicious, or flinty ; if they are without much 

 difficulty broken to pieces with the fingers, and can be scraped 

 by a knife to powder, they are aluminous, or clayey : or if 

 when put in a wine glass, and lemon vinegar poured upon 

 them, small air bubbles ascend to the top of the, liquid, they are 

 calcaraeous. The finely divided matter wliich ran through the 

 sieve, must next undergo the test of experiment After being 

 weighed, agitate the whole in water, till the earth be taken up 

 from the bottom, and mechanically suspended, adding water 

 till this efiTect be produced. Allow the mass then to settle for 

 two or tliree minutes, and in that time the sandy particles shall 

 have all sunk to the bottom. Pour off* the water, which will 

 then contain the clay in suspension, with the insoluble earth 

 arising from animal and vegetable decomposition. The sand 

 should first be attended to; and if, from inspection, it be 

 thought either silicious or calcareous in its nature, the requi- 

 site tests may be instantly applied. By this time the mixture 

 will have deposited at tlie bottom of the vessel, the clay and 

 other earths, with the insoluble animal and vegetable matter. 

 After pouring off the water, dry tlie sedeinent, and apply a 

 strong fire by placing it on the bottom of a pot heated to red- 

 ness, and the animal and vegetable matter will burn and fly off 

 in uniform products. The remainder lying in the bottom, will 

 be found to consist of clay, magnesia, and lime. To obtain 

 accuracy, another 1-4 lb. of earth should be taken from the 

 same heap, and the whole process gone over a second tune, 

 that the operator may rectify any blunders he had previously 

 committed, and be satisfied as to the result of his experiments. 

 He should provide himself with a pair of scales, and a set of 

 weights, divided at least into ounces and drachms. Although 

 vinegar will detect lime by eflTervescence, it does not dissolve 

 it so eflfectually as the nitre, or muriatic acid ; small quantities 

 of which may be procured from the druggists at no great ex- 

 pense. The importance of sometimes resorting to an analysis 

 of the soil, will appear, from the consideration that many soils, 

 apparently of good texture, are yet "barren in a high degree, 

 when, as has been observed by Sir Humphrey Davy, common 



