84 



HEALTH AND DISEASE 



may in many cases be desirable. A town stable has, for instance, to be 

 connected with the sewerage system, for which purpose advantage is taken 

 of the sewer which is nearest to the stable, and the principal points to be 

 considered are the best method of connecting the stable drain with the 

 sewer, and whether the stable drain shall consist of an open channel or 



Fig. 470. — Wrought-iron Open Gutter 

 (St. Pancras Ironworks Co. 



Fig. 471. — Covered Surface-drain 



a closed one in the form of a pipe sunk a short distance underground, and 

 running to the outside of the stable into a trap. 



The object of trapping is to prevent the passage of gases from the sewer 

 back into the stable, and it will be understood that, in the attempt to 

 attain this very essential object, the disconnection of the stable drains by 

 this means, whatever form they may assume, should be as complete as pos- 

 sible. Undoubtedly the most simple and sanitary method is the surface- 

 drain, which may be a mere open channel 

 running from the front of the stall back- 

 wards, or it may be provided with a 

 movable cover, so as to admit of the 

 necessary cleansing and prevent obstruc- 

 tion. The two illustrations above show 

 the two systems of the open and covered 

 surface-drain (figs. 470, 471). 



hi applying the system of surface- 

 drainage, whether covered or uncovered, it is necessary that the floor 

 should be inclined in such a manner as to allow a sufficient fall for the 

 escape of the sewage. In the case of stalls the fall is necessarily from 

 before backwards. In the box it is commonly made to converge towards 

 the centre, to which all fluid matters are conveyed by grooves in different 

 parts of the flooring (fig. 472), and thence, by means of an underground 

 drain, to the outlet; but with a little ingenuity surface channels can be 

 used in boxes as well as in stalls, and are certainly better, as a drain-inlet 



Fig. 472. — Brick with Drainage Channel for 

 Stable Floor 



