642 EXPERIMENT STATION RECORD. 



and available knowledge regarding the medicinal value of various classes of such 

 waters is summarized. 



Descriptions are given of the analytical methods used in the following determina- 

 tions: Lithium, potassium, calcium, manganese, iodin, chlorin, sodium, magnesium, 

 iron and aluminum, arsenic, bromin, boric acid, nitric acid, sulphuric acid, carbonic- 

 acid, phosphoric acid, nitrous acid, silicic acid, bicarbonic acid, free ammonia, albu- 

 minoid ammonia, and oxygen-consuming capacity. "Besides these determinations, 

 barium, strontium, and hydrogen sulphid were determined in cases where there was 

 reason to suspect their presence." 



Tables show analyses of 42 samples of mineral waters from leading springs of the 

 United States represented in the open market, together with analyses advertised by 

 the spring owner, or, where they could not be obtained, the analyses given in Crook's 

 Mineral Waters of the United States. The hypothetical form of combination of the 

 constituents is also given in each case, and the general character of the waters as 

 shown by analysis is discussed. Analyses of 13 samples of water from springs at 

 Saratoga, New York, collected by an agent of the Department, are also reported. 



The results reported in the first case (with market waters) show "that the compo- 

 sition of waters as determined by the authors is often different from the composition 

 as given in the advertising matter. This does not necessarily mean that there has 

 been any attempt at fraud on the part of the owner of the spring. Sometimes the 

 difference between the analyses may be small and immaterial, falling within the limits 

 of error of analyses by different analysts and the natural change in the composition of 

 the water from time to time. 



"Sometimes the difference in analyses may be due to the fact that the advertised 

 analysis was made years ago and that since that time the composition of the water 

 has gradually but steadily changed. On the other hand, these differences may some- 

 times be due to poor analytical work on the part of the commercial chemist, sometimes 

 to fraud on the part of the retail dealer, and sometimes even to fraud on the part of 

 the spring owner." 



The study of the Saratoga waters collected at the springs shows that "(1) the 

 waters are in nearly all cases markedly weaker in mineral content than they were 

 about 35 years ago; (2) there is a great variation in the total mineral content of indi- 

 vidual springs from time to time; (3) the rarer elements, such as lithium and bromin, 

 seem to vary to a greater extent than the other elements present." 



Purifying- drinking water by electricity, R. Guenther (Mo. Consular Rpts. 

 [U. &], 1905, Xo. 297, p. 128). — This is a brief note on a simple apparatus devised 

 by a French engineer named Otto for generating ozone by means of electricity and 

 mixing it with the water to be purified. It is claimed that " the apparatus is capable 

 of purifying about 60 gal. of water an hour, and the cost per hour is about the same 

 as that of an ordinary electric incandescent light." 



Copper sulphate for killing green scums, S. Avery and A. Keyser (Breeder's 

 Gaz., 48 (1905), No. 19, pp. 935, 936).— Experiments at the Nebraska Station in tanks 

 supplying water for stock are briefly reported, the conclusion reached being that 

 "tanks may be kept free from green scums by treating with copper sulphate at least 

 3 times during the heated portion of the summer. Adding the copper sulphate 

 directly at the rate of \ lb. copper sulphate to 15 bbls. of water is the more effective 

 method of treatment. Where this treatment is used the copper sulphate should be 

 placed in a coarse sack and drawn back and forth through the water until dissolved." 



Estimation of Bacillus coli in potable waters, A. Gautie (Ann. Chim. Analyt., 

 10 (1905), pp. 254-257; abs. in Jour. Chem. Soc. [London], 88 (1905), No. 516, II, p. 

 660). — The author claims that correct estimates of the number of this organism pres- 

 ent in water can only be made by repeated experiments with varying amounts of 

 water (from 100 cc. to 1 drop). In other respects he follows the usual method of 

 adding peptone broth and a sufficient amount of phenol to prevent the growth 

 of a large number of saprophytic germs. 



