April 21, 1905.] 



SCIENCE. 



605 



and this was applied to the algal mass in 

 hopes that it would accomplish the desired 

 result. In a very short time all of the algal 

 growth was exterminated, and although the 

 first application was made in the fall of 

 1901, it has never been necessary to apply 

 copper more than once a year to these beds. 

 Naturally, the degree of success attained in 

 this work, while not in any way demon- 

 strating that a similar method would be 

 efficacious in large reservoirs, seemed to 

 warrant a more thorough investigation of 

 the subject. 



In June, 1903, our attention was called 

 to the condition of the reservoir at Win- 

 chester, Ky. This supply was constructed 

 in 1890, and after the first three years a 

 strong odor and taste were noticeable in the 

 water during the hot summer months. 

 This condition gradually increased until 

 the water attained such a degree of offen- 

 siveness as to make its use for any purpose 

 almost intolerable. Aeration and mechan- 

 ical filtration were tried without effect, and 

 it seemed that the only hope for relief was 

 to abandon the entire reservoir and go ten 

 miles to the Kentucky River for the source 

 of a new supply. The cost, however, was 

 too great to be considered, and for this 

 reason the difficulty was considerably in- 

 creased. A microscopical examination of 

 the water showed that the odor and taste 

 were due to the presence of one of the blue- 

 green alg£e, and it was believed that the 

 application of copper sulphate at the rate 

 of about 1 to 5,000,000 would be sufficient 

 to destroy these forms; consequently, there 

 being no objection on the part of either the 

 water board or the health authorities, a 

 treatment was made, and the results have 

 been everything that could be desired. 

 "Within three or four days the odor disap- 

 peared and the water was perfectly clear. 

 This summer at about the same time it -was 

 feared that the algal growth was reappear- 

 ing, and for this reason another slight 



treatment was made, but with this excep- 

 tion, no copper has been added to the water 

 since the original treatment in June, 1903, 

 and it has remained perfectly clean and 

 sweet. 



In 1892 the Butte (Montana) City Water 

 Company began the construction of a large 

 impounding reservoir for the purpose of 

 storing the water of a mountain stream 

 having its source in the summit of the 

 Rocky Mountains. The next year the 

 stored water became badly contaminated 

 and was unfit for domestic use on account 

 of its disagreeable odor and taste. In 1894 

 the dam was increased so that the capacity 

 of the reservoir was 180,000,000 gallons, 

 but the same trouble was experienced as 

 during the previous year, and further work 

 was stopped on the dam until some remedy 

 could be discovered. An extensive study 

 of the conditions to discover the cause and 

 find a remedy for the trouble was under- 

 taken, and, besides a resident chemist and 

 bacteriologist, consultations were held with 

 water engineers of note in all parts of the 

 country. It was finally decided to increase 

 the water supply flowing into the reservoir 

 and more thoroughly clean the bottom of 

 all organic matter which might contain 

 vegetable organisms. Notwithstanding the 

 efforts made in this line, the water was so 

 infected with algae as to be absolutely nau- 

 seating in odor and taste, and it became so 

 offensive that the odor was continually 

 present in the city on account of the water 

 being used in sprinkling carts. On July 7 

 of this year copper sulphate was added to 

 this reservoir in the proportion of 1 part 

 to 8,500,000 parts of water. During the 

 first twenty-four hours the water in the 

 reservoir gave off a most pronounced and 

 disagreeable odor, and at the end of the 

 second and third days changes were noticed 

 in the color and taste of the water, particu- 

 larly in the lower depths. By the end of 

 the fifth day the water assumed a natural 



