XIV. 



ON THE ADVANTAGES OF A SUPPLY OF SOFT WATER FOR 

 THE TOWN OF WATFORD. 



By Akthur King, M.B., CM., D.P.H. 



Read at Watford, 29th Jamiari/, 1895. 



Absoltttely pure water is a very rare if not an unknown 

 substance in nature, and has only been prepared by very careful 

 distillation in vessels constructed of silver. In this condition, as 

 is well known, it is composed of two elementary gases — oxygen 

 and hydrogen — in the proportion by volume of one of the former to 

 two of the latter. If we passed a current of electricity through 

 some water we should see the bubbles of gas come off at the two 

 poles of the battery, and if over each pole we placed an inverted 

 glass tube we should find that at all stages of the process we 

 slioukl have double the volume of hydrogen to that of oxygen. 

 Hydrogen is an inflammable gas, and oxygen is what is called 

 a supporter of combustion ; that is, it unites with bodies of the 

 nature of hydrogen to give out light and heat, a new body being 

 formed. Coal gas is largely composed of hydrogen and carbon 

 or charcoal, and we know that when we heat it to a certain 

 temperature it bursts into a flame, uniting with the oxygen of the 

 air, two new bodies being formed, namely, water and carbonic 

 acid gas. Perhaps some people do not quite appreciate the full 

 importance of water to living beings, especially human beings. It 

 forms about three-quarters by weight of the body of animals, 

 a large percentage of all our drinks, and from about 10 to 80 per 

 cent, of the different food-stuffs. It occurs largely dissolved in the 

 atmosphere in the form of vapour. In this way it moderates the 

 direct heat of the sun, and, still more important, it prevents the 

 earth from losing heat by radiation ; indeed, if it were not for this 

 watery vapour the earth would not be a tit place for us to live on, 

 for its whole surface would be frozen in a single night. I mention 

 this presence of water in the air because it is of the utmost 

 importance in connection with the question of water-supply. 



Our main reservoir for water is the ocean, covering as it does 

 nearly three-quarters of the surface of the earth. Unfortunately 

 we do not all live near the sea, and, if we did, the large quantity of 

 salts dissolved in sea-water would prevent our using it for drinking 

 or domestic pui-poses. Nature, however, comes to our rescue, and 

 by distillation and evaporation the sea gives up a large quantity 

 of its water to the atmosphere in a very pure condition, retaining 

 the salts itself. The warmer the air the more water it will absorb, 

 and when this heated air comes to colder portions of the earth it 

 cannot hold so much water ; clouds are formed, and eventually the 

 sur])lus water falls in the form of rain. In this country we are 

 chiefly supplied with water distilled from the seas which lie 



