| Designation of materials. | Diameter (Millimeters) | Velocity (Hydr. V.) | |
|---|---|---|---|
| Millimeters per sec. | (A) | ||
| Grit | 1-3 | ||
| Sand | .5-1 | ||
| .50 | 64 | 0.06 | |
| .30 | 32 | ||
| .16 | 16 | ||
| .12 | 8 | 0.08 | |
| Silt | .072 | 4 | 0.02 |
| .047 | 2 | 0.04 | |
| .036 | 1 | 0.08 | |
| .025 | 0.5 | 0.08 | |
| .016 | 0.25 | 2.00 | |
| .010 | 0.25 | 21.15 | |
| Clay | ? | 0.0023 | 74.65 |
| 98.16 | |||
| (Z) | 9.09 | ||
| Ferric Oxid | 0.13 | ||
- (B) = 248 Tallahoma Subsoil. Jasper Co.
- (C) = 165 Flatwoods Soil. Chickasaw Co.
- (D) = 206 Pine Hill Soil. Smith Co.
- (E) = 209 Pine Hill Subsoil. Smith Co.
- (F) = 397 Oxford Subsoil. Lafayette Co.
- (G) = 219 Table Lands Subsoil. Benton Co.
- (H) = 173 Prairie Subsoil. Monroe Co.
- (I) = 230 H’y Flatwoods Soil. Pontotoc Co.
- (J) = 246 Red Hills Subsoil. Attala Co.
- (K) = 196 Hog-wallow Subsoil. Jasper Co.
- (Z) = Hygroscopic Moisture (+7 = to +21°C)
| Designation of materials. | Mississippi Uplands. | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Sandy | Loam | Clay | ||||||||
| (B) | (C) | (D) | (E) | (F) | (G) | (H) | (I) | (J) | (K) | |
| Grit | 6.94 | 2.90 | 0.36 | 0.36 | 0.23 | 2.10 | 0.33 | 1.97 | 0.83 | |
| Sand | 17.65 | 6.96 | 2.98 | 0.83 | 0.35 | 1.19 | ||||
| 18.81 | 2.81 | 6.62 | 6.21 | 0.79 | 1.47 | 0.62 | 0.72 | 1.96 | ||
| 10.16 | 4.41 | 7.75 | 3.38 | 2.33 | 2.32 | 1.64 | ||||
| 2.66 | 3.13 | 3.01 | 3.85 | 1.17 | 2.09 | 0.88 | ||||
| 1.66 | 2.02 | 1.59 | 1.49 | 0.18 | 0.78 | 0.20 | 0.23 | 0.70 | 0.26 | |
| Silt | 1.02 | 2.23 | 1.19 | 0.64 | 0.78 | 0.76 | 1.26 | 0.18 | 1.29 | 0.19 |
| 0.88 | 5.06 | 3.56 | 2.63 | 3.56 | 9.79 | 2.92 | 1.61 | 1.80 | 2.49 | |
| 1.96 | 9.67 | 6.50 | 5.40 | 13.12 | 7.26 | 7.36 | 2.66 | 3.60 | 3.67 | |
| 7.89 | 14.18 | 13.97 | 7.77 | 16.64 | 13.14 | 8.81 | 9.13 | 2.73 | 5.39 | |
| 8.40 | 22.03 | 14.20 | 16.65 | 27.28 | 15.07 | 7.85 | 26.64 | 3.30 | 10.31 | |
| 15.53 | 15.62 | 29.36 | 37.75 | 18.87 | 26.50 | 35.22 | 32.35 | 25.33 | 24.18 | |
| Clay | 8.63 | 7.86 | 4.58 | 10.70 | 17.23 | 19.19 | 33.16 | 25.48 | 40.25 | 47.03 |
| 99.28 | 98.68 | 95.67 | 97.77 | 98.35 | 97.65 | 99.50 | 97.87 | 96.11 | 100.00 | |
| (Z) | 1.80 | 3.36 | 2.48 | 7.69 | 8.79 | 7.24 | 11.35 | 9.33 | 18.60 | 14.48 |
| Ferric Oxid | 1.10 | (1.45) | 1.25 | 4.45 | 2.53 | 5.11 | 5.42 | (5.90) | 10.50 | 4.00 |
- (L) = 390 Buckshot Soil. Issaquena Co.
- (M) = 237 Loess. Claiborne Co.
- (N) = 365 Tallahatchie All. Soil. Panola Co.
- (O) = 377 Frontland Subsoil. Sunflower Co.
- (P) = 395 Dogw. Ridge Soil. Coahoma Co
- (Q) = Southwest Pass. Plaquemine Par.
- (R) = Southwest Mud-lump. Plaquemine Par. La.
- (Z) = Hygroscopic Moisture (+7 = to +21°C)
| Designation of materials. | Mississippi River Bottom.. | ||||||
|---|---|---|---|---|---|---|---|
| Swamp. | River. | River Deposit.Delta | |||||
| (L) | (M) | (N) | (O) | (P) | (Q) | (R) | |
| Grit | 0.09 | 0.24 | 0.09 | ||||
| Sand | 0.05 | ||||||
| 0.37 | 0.04 | 0.32 | 0.15 | 0.18 | 0.10 | ||
| 0.36 | 0.61 | 0.05 | |||||
| 0.93 | 0.21 | 2.79 | 0.47 | ||||
| 0.31 | 1.65 | 1.30 | 2.41 | 3.75 | 7.03 | 3.68 | |
| Silt | 0.27 | 1.95 | 2.68 | 16.90 | 21.46 | 12.38 | 5.34 |
| 1.56 | 14.25 | 9.38 | 19.97 | 21.83 | 13.27 | 10.09 | |
| 2.23 | 16.20 | 9.88 | 13.90 | 14.01 | 15.87 | 5.58 | |
| 3.68 | 20.08 | 20.37 | 4.27 | 9.93 | 8.25 | 9.54 | |
| 8.97 | 5.59 | 19.79 | 1.89 | 9.58 | 7.26 | 8.01 | |
| 38.19 | 33.38 | 25.30 | 30.08 | 8.65 | 19.67 | 34.46 | |
| Clay | 44.30 | 2.51 | 9.64 | 5.51 | 10.35 | 12.20 | 18.18 |
| 100.01 | 97.74 | 98.73 | 98.04 | 99.72 | 96.58 | 100.00 | |
| (Z) | 14.31 | 4.18 | 6.12 | 5.68 | 3.95 | ||
| Ferric Oxid | (5.82) | 3.27 | 2.58 | 2.31 | 2.69 | ||
- (S) = 10 Sacramento. Sacramento Co.
- (T) = 506 Gila. San Diego Co.
- (Z) = Hygroscopic Moisture (+7 = to +21°C)
| Designation of materials. | California. | |
|---|---|---|
| River Deposit. | ||
| (S) | (T) | |
| Grit | ||
| Sand | ||
| .13 | ||
| .15 | ||
| .11 | ||
| .32 | .75 | |
| Silt | 3.16 | 2.51 |
| 10.27 | 8.32 | |
| 13.67 | 12.64 | |
| 13.11 | 11.28 | |
| 43.61 | 31.79 | |
| Clay | 12.06 | 23.97 |
| 96.20 | 91.71 | |
| (Z) | 9.18 | 9.26 |
| Ferric Oxid | ||
Number of soil grains per gram.—It is of some interest to consider the number of grains of different sizes that may be contained in, e. g., a gram of soil. If for this purpose we assume all the soil grains to be spherical, we shall obtain the minimum figures, for most other shapes will pack more closely. King (Physics of Agriculture, p. 117) calculates such figures for different grain-sizes, assuming the density to be that of quartz (2.65), with the result that while with a diameter of one millimeter (1-25 inch) the number of grains would be 720, and with one-tenth of a mm. 720,000; if made of the finest particles only, viz., one thousandth of a mm., the number would be 720,000 billions. Probably few of the clayey soils we ordinarily deal with are of this order; it is doubtless approached in certain fine plastic clays.
Surface afforded by various grain-sizes.—The amount of surface afforded by a similar amount of soil must naturally be considered in this connection, since upon it depends not only the amount of moisture which the soil may hold in the form of superficial films, but also the extent of surface upon which the weathering agencies as well as the root hairs of plants may act. Quoting again from King’s work, we find on the same premises given above for the number of grains, that their surface would in the case of grains of one mm. diameter be eleven square feet per pound (about half a pint) of material; while in the case of the finest grade we should have 110,538 square feet, or more than two and a half acres.
From actual experiments made with the flow of air through various soils, King calculates that while in ordinary loam soils the total surface is about an acre per cubic foot, in fine clay soils it rises to as much as four acres. If we imagine this large surface to be covered with even a very thin film of water, it is readily seen how large an amount may be present in a cubic foot of moist soil.