278 



SCIENCE 



[N. S. Vol. LII. No. 1342 



per million of CO2 and the bicartionates in parts 

 per million of CaCOs this equation becomes: 



4.0 X 10-' , 



H-ion Concentration = 



HCO3 



■ COj + 1 X 10-'. 



When both free oar'bonio acid and bicarbonates are 

 expressed in either parts per million CO2 or cc.CO. 

 the equation becomes: 



H-ion Concentration = \rr^r\ — CO2 + 1 X 10-'. 

 XIL/U3 



Preparation of ammonia-free water: G. C. 

 Baker. Ammonia free -water may be prepared by 

 passing distilled water through permutit. This 

 method has advantages over other methods in (a) 

 ease of operation and (6) production of large 

 quantities at minimum expense. Its disadvantages 

 are (a) gives a water of higher mineral content 

 and (6) does, not remove nitrate, nitrate or al- 

 buminoid nitrogen. Indications are that American 

 Permutits, except the especially prepared EoUn 

 Permutit will not quantitatively remove ammonia, 

 but the English and German Permutits seem sat- 

 isfactory. 



Sewage treatment at Fort Myer, Virginia: J. W. 

 Sale and W. W. Skinneb. Sewage at Port Myer 

 is treated by settling, septicization, and aeration. 

 The system cost about $8,000, was designed for a 

 population of 2,000 and was used a model for 

 plants at other cantonments. A chemical and bac- 

 teriological investigation extending over a period 

 of six days showed that the effluent was stable and 

 sludge inoffensive. It is believed that this type of 

 plant warrants the consideration of small towns 

 which contemplate installing sewage disposal sys- 

 tems. 



The nitrate content of five hundred waters which 

 were considered safe from a bacteriological stand- 

 point: M. Stark Nichols. Nichols reports the ni- 

 trate nitrogen findings of 767 ground waters which 

 were found to be safe bacteriologically. 81.7 

 per cent, of the waters examined had nitrate 

 nitrogen values of between and 5 parts per 

 million, and 56.8 per cent, gave nitrate nitrogen 

 values of between and 1.0 part per million. He 

 cites extracts and data of other investigators and 

 points out that hia work as well as do that of other 

 workers, show that high nitrates are not a com- 

 ponent of normal safe waters. He cites instances 

 which show that a well may be subject to pollution 

 and yet not be detected by bacteriological meth- 

 ods. The evidence indicates, so the author believes, 

 that the nitrate determination should be made in 



addition to the bacteriological examination of 

 every ground water and if found in greater quan- 

 tities than 5 parts per million the source should be 

 considered unsafe until a competent sanitary sur- 

 vey shows no possible source of pollution. 



Seasonal variations of bacterial flora during fil- 

 tration process: Harry E. Jordan. Pollowing the 

 operation of a water purification plant in the cen- 

 tral states over a period of sixteen years — a series 

 of some 50,000 examinations in a 5-year period is 

 summarized with relation to seasonal ratios and 

 variations by various types of organisms present. 

 This data shows: (1) Bacterial concentration of 

 all types studied, and the proportion of all types 

 which are of the Goli group, is inversely propor- 

 tional to the temperature. (2) Both sedimentation 

 and filtration exercise a selective action against or- 

 ganisms of the Colon group and sterilization with 

 chloruie products exercises a remarkably increased 

 selective action against these organisms. (3) Of 

 the total number of Coli type organisms present the 

 fecal subtype survives purification processes — step 

 by step — in increasingly less proportion as the 

 temperature rises. 



A study of sewage and trade wastes at Bridge- 

 port, Conn. : W. "W. Skinner and J. W. Sale. The 

 investigation covered a period of one year and was 

 made in cooperation with the Bureau of Fisheries 

 in the interests of fish and shell-fish life. Dissolved 

 oxygen data 'were obtained and the composition of 

 about twenty efBuents determined. Metals and acid 

 from copper mills and waste dyes from textile 

 miUs were the chief problems given consideration. 

 The water in the harbor is toxic to oyster larvse. 

 Eemedial measures are contemplated. 



Charles L. Parsons, 



Secretary 

 {To be continued) 



SCIENCE 



A Weekly Journal devoted to the Advancement of 

 Science, publishing the official notices and pro- 

 ceedings of the American Association for 

 the Advancement of Science 



Published every Friday by 



THE SCIENCE PRESS 



LANCASTER, PA. GARRISON, N. Y. 



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