FIG. 90. Section of charcoal ventilator used in some metropolitan districts 92. Cross section of improved patent City ventilator with side passage for 93. Longitudinal section of improved patent City ventilator showing pas- PAGE 384 381 385 386 103. Showing the angle the charcoal is laid in the patent spiral ventilator 395 104. Trap for ventilating into the sewers .... 398 105. Section showing position of ventilating pipes 401 401 107. Mode of counteracting action of induced currents 114. System of M. Flament with extracting cowl 116. Cowl head used by M. Flament 117. Cowl head used by M. Flament 120. Ventilating cowl head of Ewbank 124. Banner's patent balance trap 402 403 125. Mothe's balance trap 141. Combined sewer and subsoil drain 142. Brooke's subsoil drain .... 143. Section of sewer trench showing filling for subsoil drainage 144. Section of sewer trench showing subsoil drains 145. Longitudinal section of Mr. R. Field's small flushing tank 146. End view of Mr. R. Field's flush tank showing syphon 147. Harrison's flushing plug .. .. PAGE 467 468 469 478 478 479 479 :: :: :: INDEX TO TABLES. TABLE 1. Shows the results of sanitary works 2. Analysis of street water .... 3. Analysis of soluble matter in street water 4. Showing distribution of Croydon rainfall 1861 to 1877 5. Table for calculating the volume of rainfall per acre 6. Volume of sewage of towns .. 7. Composition of sewage of towns 8. Proper inclination of circular sewers for velocities from 2 ft. to 6 ft. per second .. .. 91 9. Proper inclination for velocities in oval sewers (old form) when running full.... 10. Proper inclination for velocities in oval sewers (old form) when running two-thirds full .. 11. Proper inclination for velocities in oval sewers (old form) when running one-third full .. 12. Proper inclination for velocities in oval sewers (new form) when running full .... .. ..... 13. Proper inclination for velocities in oval sewers (new form) when run- .... 15. Proper inclination for velocities in circular sewers 1 ft. diameter when working under various heads .. 36 388 92 96 97 98 16. Proper inclination for velocities in oval sewers (old form) 1 ft. x 1 ft. 24. Velocities in oval sewers (old form) when running two-thirds full at various rates of inclination 25. Velocities in oval sewers (old form) when running one-third full at various rates of inclination 120 TABLE PAGE 26. Velocities in oval sewers (new form) when running full at various rates of 122 27. Velocities in oval sewers (new form) when running two-thirds full at 124 28. Velocities in oval sewers (new form) when running one-third full at 126 29. Areas and hydraulic mean depths of circular sewers 134 30. Areas and hydraulic mean depths of oval sewers (old form) 135 136 138 142 .. 35. Discharge of oval sewers (old form) when running one-third full at 146 36. Discharge of oval sewers (new form) when running full at various rates 148 37. Discharge of oval sewers (new form) when running two-thirds full at 38. Discharge of oval sewers (new form) when running one-third full at 12. Bursting pressure and tensile strength of sewer pipes 45. Showing the absorption of water and strength of bricks 47. Showing crushing strain on blocks of concrete .. .... ...... 192 194 195 216 234 234 237 238 240 241 252 264 269 270 56. Showing the fever death-rates-Bristol, Plymouth, London, Croydon 60. Showing the death-rates from diphtheria and croup in Croydon 380 61. For calculation of the equal annual amount of principal and interest LIFE and health are, in a great measure, dependent upon rightly understanding and practising those laws which constitute sanitary science. Pure air, pure water, and nutritious food, are the three great agents for promoting life and health. Any one of these once used, or combining with matter of a deleterious character, loses its vital property, and becomes, as it were, poison, unfit again to fulfil its sanitary mission, until it has been exposed to those revivifying influences which will restore its vital energy. Agents promoting life and health. Use of agents destroys their vitality. Atmospheric air consists of oxygen, nitrogen, car- Composition of bonic anhydride, and other gaseous matters. The atmosphere. average composition of the air in England consists of the following proportions of gaseous matter: In the air of towns are also found traces of sulphuretted hydrogen and sulphurous anhydride. Air is inspired by the adult human subject, as stated by Professor Pettenkofer, at the rate of about 360 cubic feet in twenty-four hours, and this quantity is about three thousand times greater in bulk than the average liquid and solid food taken for the sustenance of the B Professor Pettenkofer, and the quantity of air inspired. |