It is sometimes desirable to take samples of the subsoil to a greater depth than eighteen inches. A post-hole auger or large wood auger will be found very useful for this purpose. It is rarely necessary to take samples of subsoil to a greater depth than six feet. In taking samples the geologic formation and the general topography of the field should be noted, also the character of the previous crops, kind and amount of fertilizers employed, character of drainage and any other data of a nature to give a more accurate idea of the forces which have determined the physical and chemical properties of the sample. =56. Method Of Hilgard.=—Hilgard[39] recommends that samples should not be taken indiscriminately from any locality you may chance to be interested in, but that you should consider what are the two or three chief varieties of soil which, with their intermixtures, make up the cultivable area of your region, and carefully sample these first of all. As a rule, and whenever possible, samples should be taken only from spots that have not been cultivated, or are otherwise likely to have been changed from their original condition of virgin soils and not from ground frequently trodden over such as roadsides, cattle paths, or small pastures, squirrel holes, stumps, or even the foot of trees, or spots that have been washed by rains or streams, so as to have experienced a noticeable change, and not be a fair representative of their kind. He further suggests that the normal vegetation, trees, herbs, grass, etc., should be carefully observed and recorded, and spots showing unusual growth be avoided whether in kind or quality, as such are likely to have received some animal manure or other outside addition. Specimens should be taken from more than one spot judged to be a fair representative of the soil intended to be examined as an additional guarantee of a fair average. After selecting a proper spot pull up the plants growing on it, and scrape off the surface lightly with a sharp tool to remove half-decayed vegetable matter not forming part of the soil. Dig a vertical hole, like a post-hole, at least 20 inches deep. Scrape the sides clean so as to see at what depth the change of tint occurs which marks the downward limit of the surface soil, and record it. Take at least half a bushel of the earth above this limit, and on a cloth (jute bagging should not be used for this purpose, as its fibers, etc., become intermixed with the soil) or paper break it up and mix thoroughly, and put up at least a pint of it in a sack or package for examination. This specimen will, ordinarily, constitute the soil. Should the change of color occur at a less depth than six inches the fact should be noted, but the specimen taken to that depth nevertheless, since it is the least to which rational cultures can be supposed to reach.