[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.