Page:Popular Science Monthly Volume 22.djvu/96

86 plants from this source. In some cases the chlorine has also been determined. The absorptive capacity of soils and subsoils for water and ammonia has likewise been investigated.

The quantity and composition of drain age-waters under various conditions have been the subject of elaborate and extended experiments for many years, and the results obtained are of the greatest importance.

In 1870 three "drain-gauges" were made, each having an area of one thousandth of an acre, and inclosing the soil and subsoil in a natural state of consolidation to the depth of twenty, forty, and sixty inches, respectively. As the surface-soil in these gauges is kept free from vegetation, and no fertilizers are applied, their drainage represents, in effect, that of a bare, unmanured fallow. In the separate drains of the permanent wheat-plots facilities were provided for collecting samples of drain age-water from soils growing crops without manure, with barn-yard manure, and with a great variety of chemical manures.

Determinations of the nitrogen in rain-water were made at Rothamsted as early as 1846. The ammonia in the rain-fall for fifteen months, in 1853-'54, was determined in the laboratory at Rothamsted, and again in 1855-'56 by Professor Way. Dr. Frankland made analyses of the rain-fall, and also of dew and hoar-frost in 1869-'70, since which time a series of systematic investigations have been conducted in the Rothamsted laboratory.

A large number of samples of the drainage-waters from the experimental wheat-field were analyzed by Dr. Voelcker, the able chemist of the Royal Agricultural Society, and by Dr. Frankland, previous to 1875, while over thirteen hundred samples have been analyzed since that time at Rothamsted. The drainage of the "drain-gauges," from 1870 to 1874, was analyzed by Dr. Frankland, and since that date it has been systematically investigated at Rothamsted.

A full report of these drainage experiments is given in an elaborate paper "On the Amount and Composition of the Rain and Drainage Waters collected at Rothamsted," published in the last three numbers of the "Journal of the Royal Agricultural Society" (1881-'82), which, from its direct applications to questions of farm-practice, and the light it throws upon the obscure subject of soil-exhaustion and on the economy of manures, is undoubtedly the most valuable contribution to agricultural science that has appeared for many years.

Experiments were made for several years with plants representing the gramineous, the leguminous and other families, and also with evergreen and deciduous trees, to ascertain the amount of water given off during their growth.

Observations on the character and range of the roots of different plants, the relative development of leaf and stem, and their composition at various stages of growth, have been made in connection with