34 



stumps, and the foot of trees, nor from spots washed by streams or rain, 

 and are thus not a fair representative of the land. Avoid spots showing 

 unusual growths, whether in kind or quality. Note carefully the normal 

 vegetation, trees, herbs, grass, &c., the general character of the laud, 

 whether hilly, rolling, flat, &c., the aspect, elevation, and such pecu- 

 liarities of the soil and subsoil, their behavior in wet and dry weather, 

 the character of the crops raised on the land, in fact, every circumstance 

 that can throw any light on their agricultural qualities or peculiarities. 

 Unless accompanied by such notes and memoranda samples of soils can- 

 not be considered as justifying the amount of time and labor involved 

 in their chemical examination. 



The li soil" is that portion of the surface of the ground which is reached 

 by ordinary tillage operations, generally being from 6 to 9 inches deep ; 

 the "subsoil" is that portion which is ordinarily not touched in plow- 

 ing, lying beneath the soil. 



It is always well to know what constitutes the nature of the founda- 

 tion of the soil to a depth of, at least, 36 inches, since the question of 

 drainage, resistance to drought, c., will be influenced by the charac- 

 ter of the substratum. 



The different samples thus procured are emptied on a clean, boarded 

 surface, and thoroughly mixed, so as to incorporate the different sam- 

 ples of the same field together. The heap is then divided into four di- 

 visions, and the opposite quarters are put one side, taking care to leave 

 the two remaining ones undisturbed; these are thoroughly mixed to- 

 gether, the heap divided into quarters, and the opposite ones taken away 

 as before. This operation of mixing, dividing into quarters and taking 

 away the opposite quarters, is continued until a sample is left weigh- 

 ing about 10 or 12 pounds. 



Thus is obtained the average sample of the soil. Of course where only 

 a single sample is taken from the field this method of quartering is not 

 resorted to, but the bottom of the box i s nailed directly on and sent to 

 the laboratory, where the soil is to be analyzed. 



PREPARATION OF THE SAMPLE. 



The sample of the soil to be analyzed, after it is received in the labora- 

 tory and given an index number, is immediately spread out in a thin 

 layer on a large shallow pan and fully exposed to the warm air of the 

 room, until it is thoroughly dried at the common temperature, or, better, 

 in an air-bath at a temperature of 60 to 100 0. When it is dry and 

 friable it is carefully sampled, by the method of quartering, until a sam- 

 ple of about 150 grams is left. This is then rubbed up in a porcelain 

 mortar, taking care to avoid grinding up any of the gravel or fragments 

 of rocks, &c., which it may contain, and which are removed and esti- 

 mated, and the fine powder is then passed through a wire sieve of 25 

 meshes to the square inch. The object of this operation is to bring 



