1 66 DOMESTIC WATER SUPPLIES FOR THE FARM 



A rough test for organic matter may be made by adding to a 

 bottle (previously washed and rinsed in the water to be tested), 

 containing 8 ounces of the water, a teaspoonful of a solution 

 (obtained from the druggist) made by dissolving two grains of 

 permanganate of potash in an ounce of distilled water in a glass 

 stoppered bottle. A half teaspoonful of a 25 per cent solution of 

 chemically pure sulphuric acid, also kept in a glass stoppered 

 bottle, is then added. The water, which should now be a bright 

 pink, is to be allowed to stand for several days. If organic 

 matter is present the solution will fade; if absent it will remain 

 pink. 



Another important test is that made for the nitrites, the 

 presence of which indicates organic matter still in the process of 

 decomposition, or, in other words, of recently added pollution. 

 The average druggist will probably have to send away for the 

 materials required in this test. Two solutions are first made up 

 in a glass stoppered bottle: No. I, made by dissolving 16 grains of 

 sulpanillic acid in 10 ounces U.S. P. acetic acid; and No. 2, by 

 dissolving 4 grains of a-naphthylamine in 10 ounces of U.S. P. 

 acetic acid. To eight ounces of the water to be tested, add half a 

 teaspoonful of solution No. I, followed by the same amount of 

 solution No. 2. Stir and allow to stand ten minutes. The pres- 

 ence of nitrites will be indicated by a rich pink color. 



The determination of the presence of dangerous bacteria will 

 usually require a laboratory examination. Certain forms of sew- 

 age bacteria may, however, be recognized, if present, by the fol- 

 lowing test. To a thoroughly washed and rinsed glass stoppered 

 bottle holding about eight ounces of the water to be tested, add 

 eight grains of granulated sugar and set in a warm place in the 

 bright sunlight. If the bacteria are present, the solution should 

 take on, within eight hours, a milkiness due to the presence of 

 minute cells and strings of one of the sewage algae. 



Although the reactions outlined above may be given by sub- 

 stances other than those causing dangerous pollution, the fact 

 that they are obtained is sufficient ground for looking on the 



