Withy. — On Sanitation and Ventilation. 465 



air which we wish to remove, but to prevent the entrance of 

 the disease-germs which it carries with it. Foul air requires 

 constantly diluting with pure air, and at the same time carry- 

 ing away to a distance from our houses and our lungs. 

 Disinfectants, when used in connection with drainage, are 

 mere useless sbams. If there is any foul air entering our 

 houses we had better know of its presence by the smell, and 

 then take effectual measures to stop its entrance. Do not 

 let us be guilty of the folly of allowing it to come in and 

 then using mere palliatives to drown the voice with which it 

 warns us. 



The foregoing pages may serve to describe, and to explain 

 the reasons for adopting, an improved design for our systems of 

 sanitation; and I will now deal with details of construction, 

 and offer criticisms upon some of the appliances in common 

 use. It will be self-evident that the very best design may fail 

 from the outset if the details of construction are faulty. 



House-drain. 



The drainpipes leading from a house, whether to a cesspit 

 or to a public sewer, should be constructed of earthenware 

 socket-pipes glazed inside and out. They should never be 

 built of brick or stone, for the following reasons : (1) It is 

 almost impossible to make them tight, and (2) quite im- 

 possible to keep them so ; (3) their inner surfaces are always 

 more or less rough, and, as a consequence, they retain portions 

 of the discharges and become very foul ; (4) they cannot be 

 made, when of a small size, of the best sectional form for 

 allowing a good flushing effect to the liquids discharged into 

 them. 



An error in laying drains, and one formerly very common, 

 is to make them too large in diameter. It is now considered 

 better to make them as small as possible consistent, of course, 

 w T ith their ability to carry off the discharges. The reason is 

 that the flush of w T ater, being more concentrated, goes through 

 with greater speed and force. It thus keeps the drain cleared, 

 and also comparatively clean. If a 4in. pipe will do the w 7 ork, 

 a 6in. should never be used. In most ordinary dwelling- 

 houses the best authorities agree that the former is ample. 

 The area of a Gin. pipe is two and a quarter times that of a 4in., 

 and is only necessary in a large house having more than two 

 water-closets. 



The next important matter is the jointing of the pipes. 

 The first point to attend to is to keep the socket end uphill, 

 and the second to see that the next pipe lies fair and straight 

 in it. If a sharp turn is required, a bend exactly suiting it 

 should be used. If a gradual curve is necessary, probably a 

 little care in selecting those pipes which have not been made 

 30 



