12 EXPERIMENT STATION RECORD. 



which can be used for detecting the presence of formaldehyde in the atmosphere is 

 described. 



Evaporation observations in the United States, II. II. Kimball ( V. S. Dept. 

 Agr., Weather Bur. Doc. 327, pp. 8, figs. 2). — Reprinted from Monthly Weather 

 Review for December, 1904 (E. S. R., 16, p. 954). 



Copper as an algicide and disinfectant in water supplies, G. T. Mooke and 

 K. F. Kellekman (U. S. Dept. Agr., Bur. Plant Indus. Bui. 76, pp. -55). — This bulle- 

 tin is supplementary to Bulletin 64 of the Bureau of Plant Industry (E. S. R., 16, p. 

 238) , and gives the results of treatment under the direct supervision of representa- 

 tives of the Laboratory of Plant Physiology of a number of lakes and reservoirs dur- 

 ing the summer of 1904. Definite recommendations are given regarding the methods 

 of procedure, for the guidance of those having to deal with the question of contami- 

 nated water. 



The results are summarized as follows: 



"During the summer of 1904 over 50 reservoirs were successfully treated for the 

 removal of alg?e. From these results and from further experiments in the labora- 

 tory and elsewhere the following facts have been developed: 



"Much less copper is required to eradicate alga* from reservoirs than would be 

 necessary to destroy alga' under laboratory conditions. 



"The effect of this metal upon fish is of considerable importance and requires 

 more study. 



"The physical and chemical constitution of a water are factors to be considered in 

 determining the quantity of copper sulphate to use in a water supply. 



"The elimination of polluting forms sometimes makes possible the development 

 of other species, but so far these species hase never been the cause of complaint. 



"As a result of the sudden destruction of great numbers of polluting algae for a 

 few days immediately after treatment of a water supply there is sometimes an 

 increase in odor and taste. 



"The use of copper is an efficient emergency method for sterilizing water con- 

 taminated with the bacillus of typhoid fever. 



"Metallic copper offers a convenient and efficient means of sterilizing small 

 amounts of water. 



"Copper may be useful in the proper disposal of sewage. 



"Copper is of great value as a supplement to filtration in case of accident or 

 mismanagement. 



' ' Fnder certain conditions copper may be used to great advantage in connection 

 with filtration. 



"There is no authentic record of fatal copper poisoning, and many of the best 

 authorities do not consider copper a true poison; they hold that it is a natural con- 

 stituent of the body, and in minute quantities has no effect upon man. 



"The suggested medicinal use of copper in cholera, typhoid, and related diseases 

 seems important." 



The copper sulphate treatment for algae at Middletown, N. Y. , J. M. Caird 

 (Fngin. News, 53 (1905), No. 2, jjp. 33, 34). — The successful treatment of three reser- 

 voirs is reported. 



Interpretation of a water examination, W. P. Mason (Science, n. ser., 21 

 (1905), No. 539, pp. 648-653). — A general discussion of this subject in which " blind 

 adherence to cut and dried standards" is cautioned against, as is also the hasty 

 adoption of the copper method of purifying water. 



The softening- of hard water by heating- it under pressure, N. Knight 

 (Evgin. News, 53 (1905), No. 12, pp. 311, 312, fig. 1). — The results of comparative 

 tests of the effect on hardness of boiling water under normal pressure and under 

 pressure of 6 or 7 atmospheres are reported. 



