FOOTNOTES:
[1] The American gallon is 231 cubic inches or 0.8333 of the imperial gallon. In this work American gallons are always used, and English quantities are stated in American, not imperial, gallons.
[2] Filtration of River Waters. Van Nostrand & Co., 1869.
[3] Annual Report of Albert F. Noyes, City Engineer for 1891.
[4] Rept. Mass. State Board of Health, 1892, p. 541. See Appendix III.
[5] The method of calculating the size is given in Appendix III.
[6] A full table of frictions with various velocities and gravels was given in the Rept. of Mass. State Board of Health, 1892, p. 555.
[7] Frühling, Handbuch der Ingenieurwissenschaften, II. Band, VI. Kapitel.
[8] The American gallon is used throughout this book; the English gallon is one fifth larger.
[9] Piefke, Zeitschrift für Hygiene, 1894, p. 177.
[10] Zeitschrift für Hygiene, 1891, page 38.
[11] Journal für Gas- u. Wasserversorgung, 1891, 208 and 228.
[12] Journal für Gas- u. Wasserversorgung, 1893, 161.
[13] Samuelson’s translation of Kirkwood’s “Filtration of River-waters;” Lindley, Die Nutzbarmachung des Flusswassers, Journal für Gas- u. Wasserversorgung, 1890, 501; Kaiserlichen Gesundheitsamt, Grundsätze für die Reinigung von Oberflächenwasser durch Sandfiltration; Journal für Gas- u. Wasserversorgung, 1894, Appendix I.
[14] Lindley, Journal für Gas- u. Wasserversorgung, 1890, 501; Grahn, Journal für Gas- u. Wasserversorgung, 1890, 511; Halbertsma, Journal für Gas- u. Wasserversorgung, 1892, 686; Piefke, Zeitschrift für Hygiene, 1894, 151; and others.
[15] Appendix I.
[16] The Water Supply of Towns. London, 1894.
[17] A special species of bacteria artificially added to secure more precise information in regard to the passage of germs through the filter.
[18] Zeitschrift für Hygiene, 1894, p. 173.
[19] Report Mass. State Board of Health for 1891, p. 438; 1892, page 409.
[20] Appendix IV.
[21] Piefke, Zeitschrift für Hygiene, 1894, p, 177.
[22] Journal für Gas- und Wasserversorgung, 1887, p. 595.
[23] Zeitschrift für Hygiene, 1894, p. 172.
[24] Appendix IV.
[25] Appendix I.
[26] Glaser’s Annalen, 1886, p. 48; Zeit. f. Hygiene, 1889, p. 128.
[27] Vierteljahresschrift für öffentliche Gesundheitspflege, 1891, p. 59.
[28] Journal für Gas- und Wasserversorgung, 1891, 108.
[29] Zeitschrift für Hygiene, 1894, 182.
[30] I am informed that several other filters upon the same principle have been more recently built.
[31] Report on Water Purification at Cincinnati, page 378.
[32] Translation in German in Dingler’s Polytechnical Journal, 1832, 386.
[33] Water Purification at Louisville, page 378.
[34] Special Report Mass. State Board of Health 1890, Purification of Sewage and Water, page 747.
[35] Water Purification at Cincinnati, p. 485.
[36] Jour. of the New England Water Works Assoc., Vol. VIII, page 183.
[37] Report of the Pittsburg Filtration Commission, 1899, page 55.
[38] Rhode Island State Board of Health Report for 1894.
[39] Report of the Rhode Island State Board of Health for 1894.
[40] Report on the Investigations into the Purification of the Ohio River Water at Louisville, Kentucky. D. Van Nostrand & Co., 1898.
[41] Ohio State Board of Health Report, 1897, page 154.
[42] Report of the Pittsburg Filtration Commission, City Document, 1899.
[43] Fuller, Water Purification at Louisville, page 425.
[44] Warren, Feb. 9; June 1; July 6. Jewell, July 1; Feb. 9, 16, 17.
[45] “Removal of Iron from Ground Waters,” Journal of the New England Water Works Association, Vol. xi, 1897, page 277.
[46] Journal of the New England Water Works Association, Vol. ii, page 294. Description of plant by Supt. Lewis M. Bancroft.
[47] This number was the result of numerous counts made from fæces from persons suffering with typhoid fever in the Lawrence City Hospital in 1891 and 1892. Mr. G. W. Fuller afterward made at the Lawrence Experiment Station some further investigation of fæces from healthy people in which the numbers were considerably lower, usually less than 200,000,000, per gram and sometimes as low as 10,000,000 per gram.
[48] These experiments, so far as they have come to the notice of the author, have been made with water sterilized by heating, usually in small tubes stoppered with cotton-wool or other organic matter. In this case the water, no matter how carefully purified in the first place, becomes an infusion of organic matters capable of supporting bacterial growths, and not at all to be compared to natural waters.
In experiments often repeated under my direction, carefully distilled water in bottles, most scrupulously clean, with glass stoppers, and protected from dust, but not sterilized, has uniformly refused to support bacterial growths even when cautiously seeded at the start, and the same is usually true of pure natural waters. Some further experiments showed hardly any bacterial growth even of the most hardy water bacteria in a solution 1 part of peptone in 1,000,000,000 parts of distilled water, and solutions ten times as strong only gave moderate growths.
[49] The Water-supply of Chicago: Its Source and Sanitary Aspects. By Arthur R. Reynolds, M.D., Commissioner of Health of Chicago, and Allen Hazen. American Public Health Association, 1893. Page 146.
[50] Journal für Gas- u. Wasserversorgung, 1893, 694.
[51] Journal für Gas- u. Wasserversorgung, 1894, 185.
[52] The method of making this determination was given in the American Chemical Journal, vol. 12, p. 427.
[53] Some of the companies secure some ground water which they mix with the filtered water, and this is included in the quantities for the separate companies, but is excluded from the totals for all the companies by years.
[54] Exclusive of gravity supplies.
[55] Not in use.
[56] Under construction.
[57] Not in use.
[58] Under construction.
[59] Not in use.
[60] Under construction.
[61] Not in use.
[62] Under construction.
[63] In the Centralblatt für Bakteriologie, 1895, page 881, Reinsch discusses at length the cause of the inferior results at Altona in winter, and has apparently discovered a new factor in producing them. Owing to defective construction of the outlets for the sedimentation-basins they have failed to act properly in presence of excessive quantities of ice, and the sediment from the basins has been discharged in large quantity upon the filters, and a small fraction of the many millions of bacteria in it have passed through the filters. He has experimented with this sediment applied to small filters, and has become convinced that to secure good work under all conditions a much deeper layer of sand than that generally considered necessary must be used, and his work emphasizes the importance of the action of the sand in distinction from the action of the sediment layer, which has often been thought to be the sole, or at least the principal, requirement of good filtration.
[64] Licht- u. Wasserwerke, Zürich, 1892, page 32.
[65] Descriptions of some of the leading European ground-water supplies were given by the author in the Jour. Asso. Eng. Soc., Feb. 1895, p. 113.
[66] “Arbeiten aus dem Kaiserlichen Gesundheitsamte,” vol. xiv. p. 260.