| dc.description.abstract |
Sixty-eight samples were taken from the surface horizon of an apparently uniform virgin soil, at sites uniformly distributed over an area 8 ft by 3 ft 6 in. The concentrations of copper, magnesium, gallium, vanadium, molybdenum, and manganese were determined spectrographically in each sample. It was found that the sampling variations of. these elements, expressed as coefficients of variation, mere about 10 per cent., while the highest concentration found for each element was about twice the lowest. Although the chemical properties of these elements are quite different, their concentrations showed a pronounced tendency to rise and fall together. The sampling variations were the source of the greater part of the total error in a determination, except for manganese. |
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