COUNTRY VILLAS. 



101 



carried away as it is duly fermented, there will seldom be any overflow ; but 

 nevertheless, to provide against the possibility of this occurring, there ought 

 to be a drain from the tanks continued to the boundary of the property, and 

 thence into the nearest ditch or brook. This drain, between its origin at the 

 house and the manure tanks, ought to have all the communications with it 

 furnished with proper traps, to prevent the rising of smells; and, where it 

 commimicates with the tanks, and also at its commencement and at its exit 

 into the public drain, there ought to be either cast-iron gratings, or water 

 traps, to exclude rats. 



249. Traps to prevent smells are made of cast iron, and they are generally 

 from Gin. to 1ft. square on the upper surface, according to the quantity of 

 water that is supposed likely to pass through them. The construction and 

 action of such a trap will readily be un- 

 derstood by the section, fg. 73. ; in which 

 X is the grated covering to the basin of 

 the trap, and y the funnel through which 

 the water escapes to the drain. Water 

 falling into this trap through the cover 

 (a;) escapes by the funnel {y) ; but the 

 bell-shaped cover placed over this funnel, 

 by dipping into the water all round it, 

 pi-events the escape of air upwards. In 

 order that such a trap may be protected 



from the effects of frost, it is convenient to have it sunk 1 ft. or 1 ft. 6 in. in 

 the ground, and covered with an ordinary cast-iron grating, on a level with 

 the surrounding surface. The funnel may communicate with tlie drain, 

 either through the top or sides. As the basin of the trap will be liable, after 

 being a certain time in use, to become filled up with sand or other earthy 

 matters, the grated cover to which the bell is attached is not fixed to the 

 basin, but may be lifted out at pleasure, to admit of emptying the lattei*. 



250. A water-trap, for the purpose of preventing the progress of rats along 

 a drain, is formed by sinking a pit in the 

 bottom of the drain, say 1 ft. 6 in. or 2 ft. 

 deep, and suspending a piece of flagstone 

 across it, from within half an inch of the 

 cover of the drain, to within G in. of its 

 bottom ; the flagstone being built into 

 the sides of the drain and pit. This 

 construction will readily be understood 

 by the vertical section, fig. 74., and the 

 horizontal section, fig. 75. In these 

 sections, a a represent the line of direc- 

 tion of the drain; h the flagstone which 

 forms the dip or trap; and c the flag- 

 stone which serves as a cover, and which admits of being taken off without 

 disturbing the dip-stone, in order to clear 

 out the well, or pit, of the trap. The 

 action of such a trap is sufficiently 

 obvious. No animal can pass it without 

 diving under the dip-stone ; and this, it 



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