AIR WATER SOILS. 289 



"It is therefore desirable that some new, cheap, harmless, and effective method 

 be devised for ridding reservoirs of these pests. 



"It has been found that copper sulphate in a dilution so great as to be colorless, 



tasteless, and harmless to man is sufficiently toxic to the alga? to destroy or prevent 

 their appearance. 



"The mode of application makes this method applicable to reservoirs of all kinds, 

 pleasure ponds and lakes, fish ponds, oyster beds, water-cress beds, etc. It is also 

 probable that the method ran be used for the destruction of mosquito larva'. 



"At ordinary temperatures 1 part of copper sulphate to 100,000 parts of water 

 destroys typhoid and cholera germs in from 3 to 4 hours. The ease with which the 

 sulphate can then be eliminated from the water seems to offer a practical method of 

 sterilizing large bodies of water, when this becomes necessary. 



"The use of copper sulphate for the prevention of disease is regarded as incidental 

 and is not designed in any way to supplant efficient preventive measures now in use. 

 It is believed, however, that up to this time no such satisfactory means of thor- 

 oughly, rapidly, and cheaply sterilizing a reservoir has been known. Since the 

 selective toxicity of copper sulphate renders it fatal to pathogenic forms peculiar to 

 water, while the saprophytic or beneficial bacteria are unaffected, the method is 

 particularly well adapted for this purpose. . 



"Definite knowledge in regard to what organisms are present, the constitution of 

 the water, its temperature, and other important facts are necessary before it is possi- 

 ble to determine the proper amount of copper sulphate to be added. A microscop- 

 ical examination thus becomes as important as a bacteriological or chemical analysis. 



"No rule for determining the amount of copper sulphate to be added can be given. 

 Each body of water must be treated in the light of its special conditions. 



"The cost of material for exterminating alga; will not exceed 50 to 60 cts. per 

 million gallons and will usually be less. The destruction of pathogenic bacteria 

 requires an expenditure of from $5 to $8 per million gallons, not -including the cost 

 of labor." 



Some refined methods in water purification, W. G. Toplis (Amer. Jour. 

 Pharm., 76 {1904), No. •/, pp. 116-121). — A general discussion of some, features of 

 bacteriological examination of water, including a description of a filter of slag and 

 sponge clippings in use at the lower Koxborough filter plant on the Schuylkill River. 



Some water analyses, J. Sebeliex {Hi r. Norges Landbr. Hoiskoles Virfcs., 1902-3, 

 pp. 171-17? ). — The paper reports and discusses the results of monthly examinations 

 of water of different origin used for various purposes at the Agricultural College of 

 Norway. — f. w. woll. 



Well waters from farm homesteads, F. T. Shttt ( Canada Expt. Farms Hj/ts. 

 1903, pp. 158-161). — The results of analyses with reference to sanitary condition of 

 55 samples of water from miscellaneous sources are reported. 



Cooperative fertilizer experiments on moor soils, 1903, H. vox Feilitzen 

 Svmsk Mosskult. Tidskr., 18 {1904), No. 3, pp. 157-170).— The report contains a brief 

 account of the fertilizer experiments conducted under the direction of the Swedish 

 Moor Culture Association during 1903. Fifty-five different trials were conducted in 

 all, in 17 different counties, with small grains, legumes, roots, and tubers. The 

 practical results of the trials are summarized at the end of the report, and brief gen- 

 eral directions for the best methods of cultivation of moor soils are given. — 1\ w. w< >u.. 



Soils, T. S. Dvmoxd and F. Hughes (Essex Education Com., Notes Agr. Anal. 

 County Tech. Labs., 1904, pp- 7-15, 32, 33). — Mechanical and chemical analyses of 24 

 samples of soil are reported and discussed with reference to their requirements for 

 the production of different kinds of crops. The analysis of a sample of the soil from 

 the celebrated potato-growing district near Dunbar, in Essex, shows the presence of 

 high percentages of organic matter, nitrogen, available phosphoric acid, and lime, 

 but only about the average amount of potash. 



