so important for a knowledge of the natural conditions for the application of fertilisers, belongs, strictly speaking, to the province of agriculture. In Russia the first foundation of a scientific fertilisation has been laid by Dokuchaeff. As an example only, we will give the composition of four soils; (1) The black earth of the Simbirsk Government; (2) a clay soil from the Smolensk Government; (3) a more sandy soil from the Moscow Government; and (4) a peaty soil from near St. Petersburg. These analyses were made in the laboratory of the St. Petersburg University about 1860, in connection with experiments on fertilisation (conducted by me) by the Imperial Free Economical Society. 10,000 grams of air-dried soil contain the following quantities (in grams) of substances capable of dissolving in acids, and of serving for the nourishment of plants. (1) (2) (3) (4) Na_{2}O 11 5 4 4 K_{2}O 58 10 7 5 MgO 92 33 19 7 CaO 134 17 14 11 P_{2}O_{5} 7 1 7 3 N 44 11 13 16 S 13 7 7 6 Fe_{2}O_{3} 341 155 111 46 By chemical and mechanical analysis, the chief component parts per 100 parts of air-dried soil are Clay 46 29 12 10 Sand 40 67 86 84 Organic matter 3·7 1·7 0·6 4·1 Hygroscopic water 6·3 1·3 0·8 1·9 Weight of a litre in grams 1150 1270 1350 960 The black earth excels the other soils in many respects, but naturally its stores are also exhausted by cultivation if nothing be returned to it in the form of fertilisers; and the improvement of a soil (for instance, by the addition of marl or peat, and by drainage and watering), and its fertilisation, if carried on in conformity with its composition and with the properties of the plants to be cultivated, are capable of rendering not only every soil fit for cultivation, but also of improving its value, so that in the course of time whole countries (like Holland) may clearly improve their agricultural position, whilst under the ordinary _régime_ of continued exhaustion of the soil, entire regions (as, for instance, many parts of Central Asia) may be rendered unfit for any agriculture.