invaluable for the turnip crop, and on another farm they were useless, attracted his attention a good deal.' The investigations which Lawes made to discover the reason for this may fairly be regarded as the germ of the Rothamsted experiments, which subsequently became world-famous.
Observing the beneficial results upon his own turnip crops at Rothamsted by dressing them with bones dissolved in sulphuric acid, Lawes took out in 1842 a patent, in which he showed how apatite and coprolite and other mineral or fossil phosphates might be converted into a potent manure by treatment with sulphuric acid. He thus laid the foundation for what speedily became and still remains a very important industry, and he was indeed the pioneer of the now very large agricultural manure trade. The first factory for the manufacture of mineral superphosphate was started by Lawes at Deptford in 1843 ; he built a second and much larger factory at Barking Creek in 1857 (see historical description by J. C. Morton in Agric. Gazette, 2 Jan. 1888, p. 8). He sold the manure business to a company in 1872 ; but he had at that time embarked in other branches of chemical manufacture (citric and tartaric acid), and remained actively engaged in business in London up to the time of his death.
But 'all the time he was accumulating a fortune by business in London, he was at home spending a fortune in laborious scientific agricultural investigations' (R. Warington, F.R.S., in Agric. Gazette, 17 Sept. 1900, p. 180). In 1843 he started on a regular basis the Rothamsted agricultural experiment station ; and in June of that year called to his aid, as coadjutor and technical adviser, Dr. (afterwards Sir) Joseph Henry Gilbert. Together Lawes and Dr. Gilbert instituted and carried out a vast number of experiments of enormous benefit to the agricultural community at large, the details of which were recorded in the 'Philosophical Transactions of the Royal Society,' the Journals of the Chemical Society and of the Royal Agricultural Society, and other publications. Two main lines of inquiry were followed — the one relating to plants, the other to animals. In the former case the method of procedure is described in the official 'Memoranda' in which it was shown how endeavours had been made 'to grow some of the most important crops of rotation, each separately, year after year, for many years in succession on the same land, without manure, with farmyard manure, and with a great variety of chemical manures, the same description of manure being as a rule applied year after year on the same plot. Experiments on an actual course of rotation without manure and with different manures were also made : 'wheat, barley, oats, beans, clover and other leguminous plants, turnips, sugar beet, mangels, potatoes, and grass crops having been thus experimented on. The main object of the experiments on animals (commenced in 1847) was to ascertain how they could be most economically fed for human consumption ; but incidentally information of great value was obtained towards the solution of such problems as the sources in the food consumed of the fat produced in the animal body, the characteristic demands of the animal body (for nitrogenous or non-nitrogenous constituents of food), in the exercise of muscular power, and the comparative characters of animal and vegetable food in human dietaries.
In all 132 separate papers or reports on the Rothamsted experiments were published during Lawes's life, most of them in the joint names of himself and Dr. Gilbert. A full list of these is contained in the 'Memoranda of the Origin, Plan, and Results of the Field and other Experiments ... at Rothamsted,' now issued annually by the Lawes Agricultural Trust Committee. The 'Journal of the Highland and Agricultural Society of Scotland' for 1895 contains a summary (354 pages), by Sir John Lawes and Sir Henry Gilbert themselves, of several series of the experiments, with photographic portraits of both authors, and a view of the manor house.
This did not, however, exhaust Lawes's literary activity, for he was occasionally prevailed on to lecture in public to farmers' clubs, and a lengthy letter by him, estimating the produce of the wheat crop in the United Kingdom, was an annual feature of the 'Times' newspaper in every autumn from 1863 to 1899. He would often moreover write short pithy practical papers for the agricultural press on various phases of the Rothamsted experiments, or expressing in terse and forcible language his own views on some agricultural question of the day.
The unique feature of Rothamsted — which is now the oldest experiment station in the world — is the long unbroken continuity of the investigations. To provide for their permanent continuance, Lawes constituted by deed, dated 14 Feb. 1889, three trustees, to whom he leased the laboratory and certain lands at Rothamsted for ninety-nine years at a peppercorn rent, and conveyed to such trustees the sum of 100,000l. as an endowment fund. Under that deed a 'Lawes
