5i6 Reading-Course for Farmers. 



ordinary family may fairly be taken at twenty gallons per head per day. 

 In city waterworks, one of the greatest causes of excessive consumption 

 is the waste and leakage of the main pipes and house fixtures. The 

 amounts given above presuppose no leakage, and if the entire system 

 is not kept tight this amount may be doubled. 



It is further to be noted that this amount is the average quantity 

 used through the twenty-four hours, this being a convenient way of de- 

 scribing the amount. Practically, it is all used in twelve hovirs, and it 

 is a common practice to assume that the rate at which the water is used 

 during the day is twice that of the daily average. This is important, for 

 instance, if water has to be pumped and the size of the pump or the size 

 of the piping is being determined, as will be seen later. 



There is still another factor which affects the amount of water, viz. — 

 the daily and seasonal variations. Through the summer months, more 

 water is used than in winter, and on some days in the week, — for ex- 

 ample, on wash day. — more w^ater is used than on other days, so that it 

 will be wise to provide for a possible rate of flow of fifty per cent in 

 excess of the twelve-hour average. The computation for quantity would 

 then be as follows, assuming ten persons in the house : 



10 persons at 20 gallons per day 200 gallons. 



200 gallons in 12 hours means in 24 JyDurs 400 " 



And fifty per cent for excess on certain days and hours. . . .200 " 



Total maximum rate per day 600 " 



Total maximum amount per day 300 " 



This is about ten barrels, and would require a tank about four feet square 

 and three feet deep for the day's supply. This doubtless seems large, and, 

 of course, it is more water than would be used when it all has to be 

 pumped and carried by hand, but with faucets and other fixtures it is not 

 excessive and arrangements should be made to provide at least this 

 quantity." 



2. Quality of zvatcr 

 The quality of a water is, of course, only definitely known by chemi- 

 cal or other analysis, and yet common sense will be of great service in 

 aiding one to select a proper source of water supply. No water is per- 

 fectly pure, and nature does not intend man to use chemically pure w^ater, 

 for certain salts and metals in solution are necessary for the human body. 

 On the other hand, there are some kinds of pollution which are unde- 

 sirable and even dangerous. The most common forms in which this 

 pollution comes are in the form of lime or magnesia, which makes the 

 water hard. There is no great danger in drinking hard water, so far as 

 medical knowledge goes, although a person accustomed to soft water will 

 probably suffer temporary discomfort on changing to the other. The 

 chief objection to hard waters is in the large amoimt of soap needed with 



