Caption: Board of Trustees Minutes - 1880
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127 6. The amount of tannin in the ripe seed shows conclusively that the cane should be topped before expressing the juice, as an excess of tannin, especially in presence of lime, would tend to darken the sirup. INVESTIGATIONS IN CHEMICAL LABOKATOBY OF STUDENTS CONTAMINATION OF CISTERN AND WELL WATER BY ORGANIC MATTER. The investigation of this question was made the subject of thesis by Mr. C. F . Cook, of the class of 1880. The specimens of water were collected in the towns of Champaign and Urbana, and in all cases but one were used for drinking water. We here omit the names of the parties using the water. The organic matter was determined by what is known as Kubel's method, so modified that the amount of permanganate of potossium required to oxidize the nitrites and ferrous salts, when present, was deducted from the total quantity of potassium permanganate consumed. The organic matter in each specimen of water was determined twice, and, if the results disagreed, a third determination was made. The following tables give the results of Mr. Cook's valuable work, from which some interesting and useful conclusions can be drawn. The results are calculated for 1,000,000 parts of water: I.—WELL WATERS. Organic matter Organic matter Potassium permanganate required Potassium permanganate required Specimen of water. Specimen of water. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 1.84 17.29 14.30 1.90 1 36 7.08 3.10 1.63 1.41 0.82 0.82 1.27 1.83 2.25 4.76 1.09 | 1 1 1 9.20 86.45 71.50 9.50 6.80 35.40 15.00 8.15 7.05 4.10 4.10 6.35 9.15 11.25 23.80 5.45 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 5.03 0.42 11.98 0.54 6.53 2.31 0.68 0.98 1.00 1 1.97 1 3.54 4.23 1.12 2.25 0.84 1.41 25 15 2 10 59 90 2 70 32 65 11 55 3 40 4 90 4 75 9 85 17 70 21 15 5 60 11 25 4 20 7.05
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