128 EXPERIMENT STATION RECORD. 



latter period. The figures do not show that the cannonading had been an 

 effective means of protection. 



Geology and water resources of the San Luis Valley, Colorado, C. E. Sieben- 

 THAL (C7. S. Geol. Survey, Water-Supply Paper No. 2JfO, pp. 128, pis. 13, figs. 

 15, map 1). — This report is based upon field worli done in 1904. The report 

 attempts " to present such a summary of the geologic conclusions of previous 

 workers together with the observations of the writer as would give to the 

 reader a comprehensive view of the geology of the San Luis Valley and the 

 surrounding rim and enable him to understand the relation of the artesian 

 basin to the geologic structure; to give a description of the artesian basin, its 

 development, and its prospects; finally, to make accessible to the reader such 

 information in regai'd to climate, agriculture, irrigation, and water resources 

 as is available and of general interest." 



The water supplies, sewerage, and subways of Paris in relation to the 

 present floods, H. A. Soper (Engin. News, 63 (1910), No. 5, p. m,' abs. in 

 Wasser u. Abwasser, 3 {1910), No. It, p. llfl). — This article describes the hy- 

 drology of the Seine and its course and flow with reference to the underground 

 structures, sewers, subways, etc., of the city of Paris. The two separate and 

 complete water supplies, one from spring water and filtered river water for 

 drinking purposes, and the other from the river direct for other uses, are de- 

 scribed, as are also the methods of sewage disposal with reference to the water 

 supply. The data given which are of special agricultural interest are the area 

 and efficiency of the various sewage farms maintained by the city. On these 

 farms irrigation sewage is applied at an average rate of 10,000 gal. per acre per 

 day by the furrow system of irrigation. 



On the conditions of effective filtration of subterranean waters in limestone 

 formations, E. van den Rroeck .Tud E. A. Martel (Compt. Rend. Acad. Sci. 

 [Paris], 151 (1910), No. 12, pp. 57^-576; ahs. in Rev. Sci. [Paris], J,8 (1910), 

 II, No. 11), pp. Ijlfli, Ji-'t5). — It is shown that waters from certain limestone forma- 

 tions are well filtered and potable and that improper filtration occurs only where 

 there are faults and fissures in the limestone. 



A pure water supply for the farm (Canad. Farm., 2 (1910), Nos. 17, p. 3; 

 18, p. 3, fig. 1; 19, p. 2, figs. 2; 20, p. 5, fig. 1; 21, p. 3, figs. 3; 22, p. 2, figs. 2; 

 23, p 2, fig. 1; 24, p. 2, figs. 2; 25, p. 2, figs. 2; 26, p. 2, figs. 3; 3 (1910), Nos. 

 1, p. 2, figs. 3; 2, p. 2, figs. J,; 3, p. 2, figs. 2; 1,, p. 2, figs. 3; 5, p. 2, fig. i).— This 

 is a series of popular articles on this subject by F. T. Shutt, F. C. Harrison, 

 O. J. Lynde, W. T. Conuell. 



Sterilization of polluted water by ultraviolet rays, K. C. Grant (Engin. 

 News, 6.'i (1910), No. 11, p. 275, figs. 3). — The apparatus and methods used in 

 experiments in the physiological laboratory of the Sorbonne in Paris are 

 briefly described. 



In brief, the process used consisted in exposing the water to the ultraviolet 

 rays from a quartz tube mercury arc lamp (" Westinghouse silica" type) sus- 

 pended close to (2 cm. above) the surface of the water. Two such lamps, 

 requiring 660 watts per hour, were sufficient to sterilize water containing 5,000 

 micro-organisms per cubic centimeter flowing through a trough below them at 

 the rate of 1,270 cu. ft, per hour, or 960 cu. ft. per kilowatt hour. "At a cost 

 of 1 cent per kilowatt hour, therefore, it costs about $1.40 for lamp energy to 

 sterilize 1,000,000 gal." It is stated that these experiments have demonstrated 

 the commercial possibility of purifying water in large quantities by means of 

 ultraviolet rays. 



Sewage disposal plants for private houses, A. Marston and F. M. Okey 

 (Iowa State Col. Engin. Expt. Sta. Bill., Jf (1909), No. 6, pp. U, fiffs. 6).— This 

 bulletin embodies the results of experience with four experimental plants built 



