572 



SCIENCE 



[N. S. Vol. XXIX. No. 745 



the atmosphere in fumes from smelters> which 

 shoiild, and probably can be, partly saved. 

 Electro-chemistry is rapidly developing a 

 large group of new industries, making such 

 metals as aluminum, magnesium and calcium 

 available for use, and it is reaching out into 

 other fields of electrometallurgy in which elec- 

 tric heat, generated by water power, will be 

 used for smelting other metals, thereby re- 

 ducing the consumption of coal. 



In forestry also, the influence of the chem- 

 ist is distinctly felt. The sprays, used for de- 

 stroying noxious insects, are chemical prepa- 

 rations. The manufacture of wood alcohol 

 is a chemical process, which may be either 

 wasteful or economical. Turpentine is now 

 produced wastefully, but the waste can be 

 diminished by careful refining, and further- 

 more, the chemist can aid in discovering sub- 

 stitutes for it. Substitutes for tan bark are 

 also to be sought for by means of chemical 

 investigations. Another distinctively chemi- 

 cal operation is the preparation of wood pulp 

 for paper making, a process which is now 

 wasteful in the highest degree. It is esti- 

 mated that for every ton of pulp now made 

 by the sulphite process more than a ton of 

 waste material is allowed to drain away into 

 our streams. How to make this material 

 useful is a chemical problem, and so also, in 

 great part, is the investigation of other, now 

 useless fibers, which may replace the more 

 valuable wood. The preservation of wood 

 from decay is still another art in which chem- 

 istry is predominant. 



In preserving the fertility of our land, 

 chemistry has an important part to play. 

 Our knowledge of fertilizers, of the food on 

 which crops can thrive, is entirely chemical so 

 far as accuracy is concerned, and must be ap- 

 plied in accordance with chemical principles. 

 A fertilizer which is useless, and therefore 

 wasted on one soil, may be needed on another. 

 Certain fertilizers, like the Stassfurt salts, 

 Peruvian guano, the Chilean nitrates, and 

 phosphate rock are limited in quantity, and 

 their future exhaustion must be considered 

 now. What shall replace them in the future? 

 Already processes have been devised for fixing 



the nitrogen of the atmosphere and rendering 

 it available for plant food. Saltpeter and 

 other nitrates can be and long have been made 

 from waste materials such as old mortar and 

 animal refuse. The phosphatic slags have 

 been mentioned in connection with metal- 

 lurgical processes. These sources of fertility 

 are important, but greater still is the source 

 found in our municipal sewage. The prob- 

 lem of its salvage has been worked out in 

 some localities, but in the United States the 

 people are only beginning to be aroused to its 

 importance. Enormous masses of material, 

 easily available for fertilizing purposes, now 

 drain into our rivers or directly into the sea. 

 Another question, now under investigation, is 

 the possibility of using our common feld- 

 spathic rocks in fine powder, to replace the 

 potassium withdrawn by plants from the soil. 

 The relations between the chemical compo- 

 sition of water and the conservation of nat- 

 ural resources are of intimate and funda- 

 mental importance and some of them have 

 been mentioned under other headings. The 

 rate at which the land surface of the United 

 States is being transported to tide water has 

 recently been estimated by means of chemical 

 analyses of river water coupled with determi- 

 nations of stream flow, and the results of the 

 computations will doubtless assist consider- 

 ably in studying soil erosion and the impover- 

 ishment of agricultural lands. In steam 

 making the chemical quality of the water 

 supply is an appreciable factor in fuel con- 

 sumption, a subject to which reference has 

 already been made. The scale that forms on 

 the boiler shell and tubes, when water con- 

 taining incrustants is used, is a poor conductor 

 of heat and, consequently, causes increased 

 expense for fuel. By detailed study of the 

 chemical composition of available boiler 

 waters, it is possible to select a supply having 

 a minimum amount of incrusting, corrosive 

 and foaming constituents, thereby effecting 

 appreciable economy in fuel. Chemical in- 

 vestigation of methods for purifying water 

 supplies, not only for boilers but for paper 

 manufacture, soap-making, and other great 

 water-consuming industries, will enable man- 



