616 EXPEEIMENT STATION RECORD. 



waters from 126 localities, and of 15 samples of deep well water, are reported 

 and discussed. A study was also made of the clilorin content of 103 of these 

 samples for the purpose of determining the normal chlorin content of the 

 waters of the peninsula. 



There were wide seasonal variations in free and albuminoid ammonia. 

 Nitrites were generally absent, especially in the spring and fall months. The 

 maximum observed during the winter was 0.003 part per million for streams 

 and 0.006 for reservoirs. Nitrates were rarely found. 



In connection with the determination of the nitrate content a study was made 

 of the efBciency of the phenolsulphonic acid and the reduction methods, from 

 which the conclusion was drawn that " for waters containing large amounts 

 of chlorids the nitrogen present as nitrate may best be determined by the 

 ' reduction method,' using the copper-zinc couple and oxalic acid. If the result 

 of the determination indicates a nitrogen content in excess of 5 parts per million, 

 the determination should be repeated, using the phenolsulphonic-acid method, 

 and standards prepared according to Mason's suggestion. With low nitrates 

 the error may be as much as 10 per cent, with 20 parts per million or over the 

 error should not exceed 3 per cent." 



An exceedingly high chlorin content was observed in the waters as com- 

 pared with those of the Eastern States. The normal values ranged from 10 

 to 50 parts per million. " This high chlorid content is characteristic of the 

 waters of the Pacific coast, and is due to the influence of two factors, namely, 

 the rainfall and the ocean winds." The results of the chlorin determinations 

 are mapped and " isochlors " are drawn. 



The waters are all very hard, as much as 250 parts per million in streams 

 and 150 in reservoirs being frequently observed. Temporary hardness varies 

 from 150 to 250 parts per million in streams and from 40 to 120 parts in 

 reservoirs. 



The sterilization of waters by ultraviolet rays (Bnl. Off. Internat. Hyg. 

 PuJ). [Paris], 2 {1910), No. 7, i)p. 1062-1078, figs. //).— Brief accounts are given 

 in this article of the various methods and processes which have been proposed 

 for this purpose. 



Sewage disposal, L. P. Kinnictjtt, C. E. A. Winslow, and R. W. Peatt (New 

 York and London, 1910, pp. XXVI+^S6, figs. 113; rev. in Science, n. ser., 33 

 (1911), No. 8'fl, pp. 222, 223). — This book attempts to discuss somewhat fully 

 the fundamental principles of chemistry and bacteriology involved in sewage 

 treatment, including also the more important engineering aspects of sewage 

 disposal works. 



" It is hoped that the book may be useful to the student of sanitary engineer- 

 ing who alms to fit himself for the construction of sewage disposal works, to the 

 engineer who after working in other lines is drawn into this growing field, and 

 to the chemist, the bacteriologist, and the public health ofiicial concerned in 

 the operation of disposal works after they are built." 



The chapters of special agricultural interest are those relating to disposal 

 of sewage sludge and purification of sewage by broad irrigation and sewage 

 farming. 



The authors accept the British Commission's conclusions as to the low fer- 

 tilizing value of sludge. Sewage farming is considered practicable under cer- 

 tain conditions, particularly where rainfall is light and a sufficient area of 

 light sandy soil is available. The difficulty in the way of using this method is 

 increased in the United States on account of the excessive use of water and 

 the resulting large volume and diluted character of the sewage. The authors 

 are of the opinion that the tendency is away from the use of this method 

 even in those countries where it has heretofore been most successfully employed. 



