Decekuek 0, 11)04.] 



SCIENCE. 



805 



the reaction, which in their tiirn were hj'dro- 

 lyzed in a second stage with the formation of 

 the potassium salts of the fatty acids. 



The regular program of the evening was 

 then taken up, and the following papers were 

 read: 



Inactive Thorium. Charles Baskervtlle and 



Fritz Zerban. 



The authors continued the work on the com- 

 plexity of thorium, in connection with the 

 question of its radioactivity. They did not 

 succeed, however, in entirely removing the 

 activity from active thorium preparations, but 

 they found originally inactive thorium in a 

 rock from South America. This rock is gray, 

 similar to slate, and consists mainly of barium 

 carbonate. It does not show any radio- 

 activity, emitting neither + nor — radia- 

 tions. It -contains only a small percentage of 

 thorium and no uranium. The thorium from 

 this source, identified by all the characteristic 

 reactions, did not affect the photographic plate 

 through black paper within 290 hours, nor did 

 it give any evidence of radioactivity with the 

 Elster and Geitel electroscope. Further in- 

 vestigations will be made concerning the ele- 

 mentary nature of this new variety of tho- 

 rium, as no determination of its atomic weight 

 has been made. 



This work has been assisted by the Carnegie 

 Institution. 



The Use of Copper Sulphate as an Algacide 

 in the Treatment of Water Supplies. 

 Daniel T>. Jackson, 



Since the publication of the paper by 

 Drs. Moore and Kellerman, of the Bureau of" 

 Plant Industry, U. S. Department of Agricul- 

 ture, a very wide interest has been expressed 

 in the use of copper sulphate in the treatment 

 of water supplies. During the past five 

 months more than fifty different sources of 

 supply throughout the United States have 

 been treated by this method, and the results 

 obtained have exceeded all expectations. Both 

 as an algacide and as a germicide the chem- 

 ical is remarkable. Those micro-organisms 

 which cause the greatest amount of trouble 

 from tastes and odors in water supplies are 

 the ones which are most effectively acted upon 



by this treatment. Also, the bacteria which 

 are of intestinal origin are killed off with 

 much higher dilutions than the ordinary 

 germs. 



The use of covered reservoirs to prevent 

 microscopic growths will no longer be a neces- 

 sity, as the copper sulphate treatment may be 

 applied once or twice a year and prevent all 

 trouble from those sources. The dilution re- 

 quired for such treatment is usually about one 

 part of copper sulphate to eight million parts 

 of water. This dilution is so great that in 

 order to obtain a medicinal dose of the chem- 

 ical it would be necessary for an individual 

 to drink about forty gallons of water each 

 day. After two or three days the copper is 

 absolutely removed by precipitation. 



Landscape architecture is also greatly bene- 

 fited by this" discovery, as unsightly and foul- 

 smelling green growths in ponds and lakes can 

 be easily removed and prevented. The De- 

 partment of Water Supply and the Depart- 

 ment of Parks of New York City have both 

 had waters treated by the author during the 

 summer with decided success, and in each case 

 only one treatment extending for a period of 

 one hour was necessary. The sulphate is ap- 

 plied by rowing a boat over the surface of the 

 water, from the sides of which are suspended 

 bags containing the crystals of copper sul- 

 phate. These are dissolved in the water as 

 the boat is rowed over the surface. 



The use of copper sulphate as a germicide 

 is being very extensively experimented upon, 

 and it is probable that typhoid fever will be 

 entirely removed from any source of supply by 

 a dilution of one part copper sulphate to two 

 million parts water. In this case it is de- 

 sirable to treat the contaminated stream or 

 portions of supply at the source of the con- 

 tamination, the treatment being applied at 

 such a dilution that bacillus coli is removed. 



Great credit is due Drs. Moore and Kel- 

 lerman for their remarkable discovery of this 

 treatment, which marks a decided advance in 

 sanitary science and which undoubtedly will 

 modify many engineering ideas regarding 

 water supplies. 



F. H. PODGH, 



Secretary. 



