. A treatise on hygiene and public health . fillthe basin. It is urged as an objection to the use of water as a means oftrapping that it is apt to be evaporated. This disadvantage is readilyovercome by filling the receptacles with water from the public hydrants,a duty which may be entrusted to policemen. Street gutters will be thebetter for such flushing in dry weather. The entrances to gullies shouldbe protected by strong iron gratings. Their use is very obvious. Tidal vaIre-9. ■— Whenever sewers empty into the sea, or into atidal stream below high-water-mark, the outlets must be protected by
. A treatise on hygiene and public health . fillthe basin. It is urged as an objection to the use of water as a means oftrapping that it is apt to be evaporated. This disadvantage is readilyovercome by filling the receptacles with water from the public hydrants,a duty which may be entrusted to policemen. Street gutters will be thebetter for such flushing in dry weather. The entrances to gullies shouldbe protected by strong iron gratings. Their use is very obvious. Tidal vaIre-9. ■— Whenever sewers empty into the sea, or into atidal stream below high-water-mark, the outlets must be protected bymeans of flaps, or valves, to prevent the water from rising in the sewers,and also to exclude the wind, which, in time of storms, may force thesewer-air through badly trapped house-drains. They are usually made ofiron, and are so balanced as to yield to the slig-htest internal pressure,and close readily and tightly by the least amount of pressure from with-out. Two kinds of self-acting tide-valves are shown at Figs. 29 and 30.(Denton.).
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Keywords: ., bookcentury1800, bookdecade1870, booksubjecthygiene, bookyear1879
