An excavation in the soil 30–50 centimeters deep, or through to the subsoil, and 30–50 centimeters square, with one side as nearly vertical as possible is made and a slice taken from this side of uniform thickness throughout, weighing 4–5 kilograms. If the subsoil is to be examined, a sample of it should be taken out in the same manner as directed for the upper soil, to the depth of about 60 centimeters. If the character of the soil varies materially in different parts of the field, samples from several spots should be analyzed separately. A small portion of the sample should be put at once in a well-stoppered bottle; the remainder may be allowed to become air-dried, by exposing it in a thin layer, in summer, to the common temperature in the shade, or, in winter, to that of a warm room, or a moderately warm drying-chamber, heated to 30°–40°; in either case it should be carefully protected from dust. At the time of taking the sample of the soil, observations should be made in regard to the following points: _a._ The geognostic origin of the soil. _b._ The nature of the underlying strata, to the depth of 1–2 meters, if practicable. _c._ The meteorology of the locality, by consulting meteorological records, if possible; otherwise, by the general opinion of the neighborhood; in this connection, the height of the locality above the level of the sea should be noted also. _d._ The management and rotation of crops in previous years. _e._ The character of the customary manuring. _f._ The amount of the crops removed in the preceding year, and, if possible, the average amount of each of the more important crops yielded by the field. _g._ The practical judgment of neighboring farmers in regard to the field. Caldwel’s method is practically identical with that of Wolff[45] which was one of the earliest of the systematic schemes for taking soil samples. =62. Wahnschaffe=[46] insists on rather a fuller preliminary statement to accompany soil samples but gives essentially the method of Wolff with some unimportant variations which add little to the value of the process. =63. Method Of Peligot.=—According to Peligot[47] the taking of samples of soil of which the physical and chemical properties are to be determined is a delicate operation. These samples should represent as nearly as possible both the good and bad qualities of a soil. In the field selected are chosen a certain number of places at least four or five per hectare. The spots selected should have a homogeneous appearance—resembling as nearly as possible the general aspect of the field. By means of a spade a few kilograms of earth are removed to the depth of the subsoil being careful to include in the sample no accidental detritus which the upper part of the soil especially may contain. The samples should be taken immediately after the crop is harvested and before any fresh fertilizer is applied. The samples are carefully mixed and placed in a glass bottle or flask.