WATER SOILS. 423 



The physiology of sea water, R. H. Tiu'e {Scle7ice, n. ser., 16 {1902), No. 402, 

 p. 43S). — In experiments made under tiie author's direction at the Woods Hole 

 Marine Biological Laborator}^ it appeared tiiat a syntlietic solution prepared in such 

 a manner as to contain the 6 chief substances present in sea water in the proportion 

 represented differed very markedly in its ])hysiological properties from sea water. 

 Subsequent studies failed to sustain the experiments, and it is clearly indicated that 

 through some error, perhaps due to the insufficient allowance for water present in 

 the salts used, less of these substances was introduced than necessary for making up 

 the solution. Since this correction has been made it has been possible to make syn- 

 thetically an artiticial sea water in which certain marine algje can develop, and also 

 many very sensitive marine animals may be kept for a considerable time, often carrj-- 

 ing out a large part of their development in the artificial mixture. 



Catalog'ue of publications relating to botany in the library of the U. S. 

 Department of Agriculture [V. S. Dept. Agr., Library Bvl. 42, pp. 242). — An 

 author list and subject index is given to the various books and pamphlets relating to 

 botany in the library of this Department, together with a list of the serial botanical 

 publications. 



WATER SOILS. 



A new process for purifying potable water, P. Guichard [Bui. Soc. Clvim. 

 Paris, 3. ht., 27 {1902), Xo. 1S~19, pp. 941-943).— In the method proposed a slight 

 excess of calcium permanganate is added to the water, and after a sufficient length 

 of time the excess is removed by the addition of iron, the insoluble oxids of iron and 

 manganese formed being removed by filtration. The latter is accomplished by 

 means of a simple form of filter press in which 2 thicknesses of sterilized paper.are 

 used. 



On the determination of the reducing capacity of natural waters, L. W. 

 Winkler [Ztsrlu-. Atmhjt. ('hem., 41 {1903) , pp. 419-426; ah.^. i)t. ('hem. Centhl., 1902, 

 II, Xo. 15, p. 958). — The author reports determinations of the reducing capacity of 

 a large number of samples of water as measured by means of permanganate solution 

 made with a view to determining the hmits of reduction for normal waters. 



The river irrigating waters of Arizona — their character and effects, R. II. 

 Forbes {Arizona Sta. Hal. 44, pp- 145-214, fig^- 12). — This bulletin records the results 

 of a systematic study begun in 1899 of the water of the three principal irrigating 

 streams of the Territory— the Salt, the Gila, and the Colorado rivers — and of sundry 

 samples from less important sources. 



" With reference to the quality of their waters for irrigation, the rivers of Arizona 

 are very changeable in character, varying in silt and salt content with the nature and 

 condition of the watershed, with the amount and location of rainfall, with climatic 

 effects such as evaporation and temperature, and under the influence of up-river seep- 

 age. With reference to the general character of their drainage waters, the watersheds 

 of the Salt, the Gila, and the Colorado rivers may be divided into (1) the mountain- 

 ous, more forested portions with greater rainfall and better drainage; and (2) the 

 more level, desert portions, receiving less rainfall, and less perfectly drained. . . . 



'The mountain flood waters in these rivers are less saline and usually contain less 

 silt than the desert flood waters, which, resulting as a rule from torrejitial downpours, 

 sweep immense quantities of alkaline salts and erosion sediments into the drainage. 



"Low waters in all cases contain higher than the average proportions of salts, 

 partly, especially in summer, because of concentration by evaporation, and largely 

 because of the predominance at such times in these streams of seepage waters, both 

 natural and, in some cases, from up-river irrigation. The amount of sediment in low 

 waters is very small. . . . 



