October 4, 1895.] 



SCIENCE. 



443 



chemist are sought for the further prepara- 

 tion of foods and fabrics for the use of man. 

 It has also secured a place in the domain 

 of public and advanced instruction, and 

 even the conservatism of the great univer- 

 sities has yielded to agricultural chemistry 

 a prominent place in the curriculum of 

 studies. Both in this country and in Eu- 

 rope hundreds of special schools and ex- 

 periment stations are found devoted largely 

 to the service of agricultural chemistry and 

 its coordinate branches of science. 



The art of fertilizing the fields, at first 

 purely empirical, has become an exact sci- 

 ence. The methods of saving and recover- 

 ing waste fertilizing products, at the pres- 

 ent time, renders many great industries pos- 

 sible which otherwise would have to yield 

 to the fierce competition which every human 

 endeavor has to meet at this end of the cen- 

 tury. Further than this the paternal efforts 

 of agricultural chemistry extend and seek 

 to recover from the mine and from the sea 

 the elements of fertility apparentlj' forever 

 lost during the centuries that have passed. 



The science of agricultural chemistry ac- 

 knowledges, without stint, its indebtedness 

 to the other fields of chemical work. In 

 its very beginning it was the simple use of 

 the principles of mineral analysis, applied 

 to the soil and its products. By this means 

 the parts of the plants which were derived 

 directly from the soil were determined, and 

 the surprising fact was thus developed that 

 nearly the whole of the vast product of 

 vegetable growth is a free gift of Heaven 

 and not chargeable to the soil. This was 

 the point of union between agricultural 

 chemistry and meteorology, and the basis 

 of the science of meteorology applied to 

 agriculture. The supply of carbon dioxid 

 and water to the growing plant becomes 

 thus a problem of the profoundest interest 

 to agriculture, and the chemist and physi- 

 cist have thus been led to study the great 

 problems of precipitation, drainage and 



irrigation as affecting the products of the 

 field. The best methods of disj)Osing of an 

 excess of rainfall, with the minimum loss of 

 plant food due to percolation of water 

 through the soil, are of no less importance. 

 In connection with this, that treatment of 

 the soil by chemical and physical means 

 which will best prepare it to distribute the 

 supply of moisture available to the advan- 

 tage of the growing plant has been carefully 

 studied. 



Agricultural science has also drawn freely 

 on the resources of organic chemistry. In 

 agricultural products are presented to the 

 students some of the most complicated as 

 well as interesting organic compounds. In 

 the growth of the plant are seen the won- 

 derful resources of the vegetable cell in the 

 way of chemical activity. The most re- 

 nowned achievements of modern synthetic 

 chemistry have consisted in the reproduc- 

 tion of some of the simpler forms of vegeta- 

 ble organic compounds. It will be admit- 

 ted, without doubt, that the simple sugars 

 are the least complicated of organic vege- 

 table products, and these have been at last 

 successfully made in the laboratorjr. The 

 step from a hexose to a hexobiose seems 

 indeed a short one, and yet it has not been 

 taken. Only step by step must we expect 

 the onward progress of synthesis until, for 

 instance, a starch is reached. Yet in the 

 progress of organic synthetic chemistry 

 already accomplished, great good has come. 

 The exact chemical relations of the sugars 

 to the aldehyds, ketones and polyatomic 

 alcohols have been established and the 

 bonds which unite the organic chemistry 

 of man to that of Nati\re clearlj' distin- 

 guished. On a former occasion, in an ad- 

 dress to the Chemical Society, I have 

 pointed out the futility of the expectation 

 that synthetic organic chemistry will ever 

 be able to take the place of agriculture, but 

 the debt agriculture owes it is one of great 

 and constantljr increasing magnitude. 



