Fuller, G. W., 118, 123, 131, 139, 140, 145, 152, 154, 161, 165. German Imperial Board of Health, 34, 51, 54, 75, 95. regulations in regard to filtration, 221. Gill, apparatus for regulation, 55. Glasgow, water-supply of, from Loch Katrine, 275. Gravel at Albany, 299. layers, 35. friction of water in, 37. screening of, for filters, 37. Grand Forks, N. D., filters at, 252. Ground-water supplies, 3. the use of, in Europe, 276. Halbertsma, H. P. N., 54, 59. Hamburg, apparatus for regulating depth of water, 59. health of, 226, 271. regulation of rate of filtration, 56. underdrains of filters at, 42. water-supply of, 269. Hamilton, N. Y., filters at, 253. Hardness, removal of, 92, 145. Harrisburg, Penn., filters at, 253. Hermany, Charles, 161. High rates of filtration without coagulant, 182. Household filters, 183. Hudson, N. Y., filters at, 251. Ice on filters, 13. Inlet regulators, 59. Impounding reservoirs, 2. Intermittent filtration, 97. application of, 111, 197. at Chemnitz, 107. at Lawrence, 100. of Pegan Brook, 110. Iron, compounds of, as coagulants, 146. in ground-waters, 186. in ground-water at Lawrence, 105. metallic, the Anderson process, 147. present as ferrous sulphate, 191. removal plants in operation, 192. Iron waters, treatment of, 189. Jewel filter, 151, 161, 162, 172, 173. Kirkwood, James P., 8, 36, 47, 51, 55, 61, 63, 67. Kümmel, 50, 51, 86. Lambertsville, N. J., filters at, 252. Lawrence City filter, description of, 100. Lawrence Experiment Station, 97. air in water filtered in winter at, 46. depth of sand removed at, 70. depth of water on filters, 46. effect of loss of head upon efficiency, 61. effect of size of sand-grain upon efficiency, 32. effect of size of sand-grain upon frequency of scraping, 32. efficiency of filters at various rates, 50. efficiency of filtration at, 86, 89. experiments with continuous filtration, 110. filters of fine sand, 31. filters of various sand-grain sizes, 32. gravel for filters at, 39. growth of bacteria in sterilized sand at, 85. intermittent filtration investigated, 97. Lawrence Experiment Station, method of sand analysis at, 20. quantities of water filtered at various losses of head, 66. wasting effluents not necessary, 75. Lawrence, typhoid fever at, 102. Leipzig, water-supply of, from wells, 276. Lime in sand, 29. sterilizing effect of, 146. as a coagulant, 145. application of, to water, 157. Lindley, 43, 51, 54, 57, 81. Literature on filtration, 277, 285.