Page:Popular Science Monthly Volume 28.djvu/713

Rh prosecuted at Rothamstead, as a practical chemist; and together they undertook a series of agricultural investigations in the field, the feeding-shed, and the laboratory. The laboratory was at first located in an old barn; but in 1854, when the friends of Mr, Lawes proposed to present him a service of plate in recognition of their appreciation of his work, he suggested that a new laboratory building would be a more appropriate and enduring as well as useful testimonial, and the money was applied for the purpose of erecting one.

The place, identified with Mr. Lawes's experiments, Rothamstead, the patrimonial estate of the investigator, is situated some twenty-five miles from London, in Herts, and is easily accessible to visitors from the Harpenden Railway station. The manor-house is described as being a remarkably fine specimen of Old English architecture, while the domain surrounding it contains some magnificent timber, including an avenue of lindens, which, for size and regularity of dimensions, are perhaps unsurpassed in the south of England. Around the family mansion lie the five hundred acres that form the experimental station, which is entirely maintained by Sir John. For the benefit of the large number of laborers whose services are required in the management of the station, Mr. Lawes many years ago formed an allotment club through which small gardens of about an eighth of an acre each can be rented. For this purpose, in 1882, sixteen acres of land had been allocated, and the whole number of allotment gardens then in cultivation was one hundred and seventy-four. The allotment area is furnished with a club-house.

The scientific discovery, says an English biographer, around which all Mr, Lawes's subsequent work centered was the disprovement of Liebig's mineral-ash theory. It was generally supposed at the time his experiments were begun that certain saline bodies; so-called mineral constituents, were essential to the growth and development of the plant, and that such substances must be furnished to it by the soil. The necessity of a certain quantity of nitrogen was recognized; but it was imagined, since wild plants could thrive without any artificial supply of nitrogen, that a sufficient amount of that element existed in the atmosphere to render it unnecessary to take any steps for increasing the supply. The cardinal discovery made by Mr. Lawes of the absolute necessity of the presence of nitrogen in the soil in order to maintain its fertility was a contradiction of this view, and led to the opening of a new field of agricultural investigation. In connection with the belief in the sufficiency of the atmospheric sources of nitrogen, it was supposed that the fertility of a soil might be maintained for an indefinite period if the different mineral constituents carried off by the crop were annually returned in duo quantity as mineral manure to the soil. Respecting these two points, and regarding the sources of nitrogen, Mr. Lawes has said: "I maintain that the amount of nitrogen supplied to our crops from the atmosphere, whether as combined