424 



CONSERVATION 



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 phos- 

 phatic slags have been mentioned in 

 connection with metallurgical proc- 

 esses. These sources of fertility are 

 important, but greater still is the 

 source found in our municipal sewage. 

 The problem of its salvage has been 

 worked out in some localities, but in the 

 United States the people are only be- 

 ginning 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 in- 

 vestigation, is the possibility of using 

 our common feldspathic rocks in fine 

 powder, to replace the potassium with- 

 drawn by plants from the soil. 



The relations between the chemical 

 composition of water and the conserva- 

 tion of natural resources are of inti- 

 mate and fundamental importance, and 

 some of them have been mentioned un- 

 der 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 coup- 

 led with determinations of stream 

 flow, and the results of the computa- 

 tions will doubtless assist considerably 

 in studying soil erosion and the impov- 

 erishment of agricultural lands. In 

 steam making the chemical quality of 

 the water supply is an appreciable fac- 

 tor in fuel consumption, a subject to 

 which reference has already been made. 

 The scale that forms on the boiler 

 shell and tubes,, when water containing 

 incrustants is used, is a poor conductor 

 of heat and, consequently, causes in- 

 creased 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 

 investigation of methods for purifying 

 water supplies, not only for boilers but 

 for paper manufacture, soap-making, 

 and other great water-consuming in- 

 dustries, will enable manufacturers to 

 make new and greater saving in many 

 raw materials other than fuel. 



Stream pollution by industrial ref- 

 use and by sewage is a source of enor- 

 mous waste in our natural resources. 

 The subject has been for many years 

 a field of research for industrial, sani- 

 tary, and biological chemists in the 

 United States, and their investigations 

 have resulted in the improvement of 

 manufacturing processes, the utiliza- 

 tion of wastes, the purification of sew- 

 age, and the protection of domestic 

 water supplies.. When the presence of 

 deleterious substances in our river and 

 lake waters has caused loss of fish life 

 and the destruction of oyster beds, the 

 chemist and the biologist have detected 

 the harmful ingredients and have sug- 

 gested methods for their removal. 

 River silt, an important source of detri- 

 ment to navigation, is also estimated 

 by the chemist. It has been fully dem- 

 onstrated that the prevention of stream 

 pollution lies not alone through injunc- 

 tions and other legal proscriptions, 

 but also in using waste materials 

 or, when that is not possible., in ren- 

 dering them harmless. The chemist 

 has much to do in protecting and pre- 

 serving the quality of our water sup- 

 ply. Upon that., in very great measure, 

 depends the preservation of our high- 

 est resource; human life. Polluted wa- 

 ters distribute typhoid fever and other 

 dangerous diseases, and so cause losses 

 which should be,, and really are, pre- 

 ventable. 



The foregoing illustrations are 

 enough to show, for present purposes, 

 the intimate connection between chem- 

 istry and the study of conservation. 

 They also bring out the fact that the 

 classification adopted by the National 

 Commission, although admirable for 

 statistical research, is not final, and that 

 it needs to be supplemented by a dif- 

 ferent subdivision of the data. The 



