RURAL ENGINEERING. 389 



coal tar. Little experience, liowever, can be quoted In support of all-tar 

 coating." 



Surface water supply of western Gulf of Mexico basins, 1914 {U. S. Geol. 

 Survey, Water-Supply Paper 388 {WIS), pp. XXXIII -{-12^, pis. 2).— This re- 

 port, prepared in cooperation with the State of New Mexico, presents the 

 results of measurements of flow made on streams in the Rio Grande River 

 and interior of New Mexico drainage basins. 



Water supplies in the Philippine Islands, II, G. W. Heise {Philippine Jour. 

 Sci., Sect. A, 10 {1915), No. 2, pp. 135-169).— This is the second report on pro- 

 viding the people of the Philippines with pure drinkng water (E. S. R., 33, 

 p. 5S7). 



It is stated that during 1914 the Bureau of Public Works drilled 120 deep 

 wells, of which 103 were successful, while Provinces and private individuals 

 drilled perhaps an equal number. The total number of deep wells in the 

 Islands is over 1,000. 



During the year about 200 chemical analyses and 2,100 biological examina- 

 tions were made, but, owing to the fact that many of the samples were not 

 properly taken and were not accompanied by sufficient data concerning their 

 sources, their sanitary analysis in a number of cases is considered of doubtful 

 value. Field investigations of the water supplies of Mindoro, Cebu. and Pauay 

 are reported, with analytical data in tabular form. In many borings, especially 

 near the coast, brackish water is encountered during the first 30 to 70 meters, 

 even though fresh water may be found at low levels. The minimum tempera- 

 ture of deep wells drilled in the lowlands is about 28° C. (82.4° F.), but the 

 temperature range is great. The deep well waters ranged in total solids content 

 from about 120 to 8,200 parts per million, and in chlorin content from 1.5 to 4,471 

 parts per million. The highest free ammonia content recorded was 32.7 parts 

 per million. " In general, the deep wells show a high degree of bacteriological 

 purity. The flowing wells, so far as known, are all sterile or very nearly so, 

 and deep-pimipiug wells seldom show any marked degree of bacterial pollution 

 except where the equipment is defective or carelessly handled." 



Of 16 surface wells examined 15 gave unmistakable evidence of pollution 

 on a single examination, while the sixteenth was so located that contamination 

 at some time seemed a foregone conclusion. " It would probably be con- 

 servative to say that the water from over SO per cent of the wells is unfit to 

 drink, and that very few of the wells are safe throughout the year. . . . The 

 surface wells, with the exception of a few located so near the ocean that they 

 were obviously contaminated by sea water, range in total solids content from 

 164 to 1,230 parts per million, and in chlorin content from 5.5 to 436 (average 

 about 150), while the highest free ammonia content noted is 0.64." 



The spring waters examined varied widely in qualitj', the total solids content 

 ranging from 24 to 6,025 parts per million and chlorin from 0.7 to 3,120 parts 

 per million, while the maximum free ammonia content was 6.2 parts per 

 million. 



The importance of the Bacterium coli in the judgement of water, E. Quantz 

 {Ztschr. Hvf/. II. Infektionskrank., 78 {19U), No. 2, pp. 193-221 ; abs. in Chem. 

 Zentbl., 1915, I, No. 11, p. 570; Centhl. Bnkt. [etc.], 2. Abt., 43 {1915), No. 17-18, 

 pp. 465, 4S6). — Tests of a large number of water supplies, mainly from wells, 

 are reported, the purpose of which was to determine the significance of 

 B. coli bacteria in judging the purity of water supplies. 



It was found that normal ground water does not contain B. coli bacteria, 

 and their presence in ground water is taken to indicate pollution from surface 

 sources. Owing to the fact that B. coli bacteria do not readily multiply nor 

 live long in water, the test is considered to be more %aluable than the total 



