388 EXPERIMENT STATION RECOED. [Vol.35 



cousin water supplies aud their chemical quality and describes local water sup- 

 plies by counties. The first part covers the geography and geology, conditions 

 controlling underground and artesian water, the flowing artesian wells of Wis- 

 consin, prospecting for flowing wells, springs, and mineral waters, the general 

 composition and uses of water supplies, chemical quality and factors affecting 

 the mineralization of underground water supplies, and surface water supplies 

 and their chemical quality. 



Bacteria in commercial bottled waters, Maud M. Obst (U. S. Dept. Agr. 

 Bui. 369 (1916), pp. 13). — Bacteriological examinations of bottled waters from 

 110 domestic springs are reported and discussed. 



From the results obtained it is concluded that " bottled water for table use 

 should either be actually sterile or should comply with a strict standard as to 

 the number of Bacillus coU tolerated. No water should be permitted to be sold 

 which is contaminated at the source in any manner. Inspection of springs and 

 bottling establishments, together with the analysis of official samples, indicates 

 that ignorance of proper precautions, carelessness, and neglect are fully as 

 large factors in the contaminations found as are impurities actually present in 

 the springs. 



" The numbers of B. coli in official samples collected in the market may be 

 safely assumed to be less rather than greater than the numbers in the freshly 

 bottled stock. The data . . . show the need of improvement in the bacterio- 

 logical condition of many of the brands of bottled water to be found in the 

 market. Careful consideration of cases to which special study has been given 

 shows that there are some springs used for the production of commercial bottled 

 waters which should not be so used. It is evident that the presence of serious 

 and unremovable contamination should shut the water of a spring permanently 

 from the market. . . . 



" The results clearly show that bottled waters can be made to conform to the 

 requirements of the U. S. Public Health Service for drinking water furnished 

 upon trains ; that is, that not more than one 10-cc. sample out of five should show 

 the presence of B. coli." 



Study of the purification of water by aluminum sulphate, A. A. Bado and 

 V, J. Beenaola (Boh Ohras Pub. Argentina, 12 {1915), No. 4-6, pp. 185-212, 

 pis. 4)- — Experiments on the purification of the La Plata River water with 

 aluminum sulphate led to the conclusion that the formula A=2 (p— 5) for deter- 

 mining the quantity of aluminum sulphate necessary for the purification of river 

 water gives results which are unnecessarily high. In this formula J.=the 

 necessary quantity in milligrams of aluminum sulphate and p=the milligrams 

 of calcium carbonate in the water. It is further concluded that owing to the 

 complexity of the factors affecting the action of the coagulant it is impossible to 

 determine exactly the qimntity of aluminum sulphate necessary for thorough 

 purification. The necessary quantity of aluminum sulphate is considered to 

 depend on the alkalinity of the water, the organic matter content, and the 

 matter in suspension. It is also concluded that the precipitated aluminum 

 hydrate adsoi-bs organic matter in solution. 



The filtering action of soil on water containing colloids, K. Sack (Osndhts. 

 Ingen., 38 {1915), Nos. ^6, pp. 525-528; 47, pp. 538-543, fig. 1; 48, pp. 549-555).— 

 Studies on the colloidal content of samples of several types of sewage and 

 colloid-holding waters, including domestic and industrial sewage and sewage 

 from septic and settling tanks, and experiments on the filtering and purifying 

 action of a crystalline powder composed of the important constituents of agri- 

 cultural soil, and of moor and humus soil containing much organic matter, 

 heavy and weak loam soils, and light sand soil, are reported. The method of 

 Marc for colloid determination was used. 



