REGARD TO FILTRATION 221 II. EXTRACTS FROM DR. REINCKE’S REPORT UPON THE HEALTH OF HAMBURG FOR 1892 226 III. METHODS OF SAND-ANALYSIS 233 IV. STATISTICS OF SOME FILTERS 241 Results of Operation 241 List of Sand Filters in Use 244 List of Mechanical Filters in Use 247 Notes regarding Sand Filters in America 251 Extent of the Use of Filters 254 V. WATER-SUPPLY OF LONDON 255 VI. WATER-SUPPLY OF BERLIN 261 VII. WATER-SUPPLY OF ALTONA 265 VIII. WATER-SUPPLY OF HAMBURG 269 IX. NOTES ON SOME OTHER EUROPEAN SUPPLIES 272 X. LITERATURE OF FILTRATION 277 XI. THE ALBANY FILTRATION PLANT 288 INDEX 317 In the table of “ANALYSES OF SANDS USED IN WATER FILTRATION” the place name “Owesty” has been corrested to read “Oswestry”. On page 270 the statement “the velocity in the drain will reach 0.97 foot” should probably read “0.97 feet per second”.