WATEK 3 



be looked at. Although we may have few diseases among 

 animals directly attributed to an impure water supply, yet 

 physiology and experience teach us that the highest degree 

 of health is only obtained when that supply is above 

 reproach, and where this is not so it is attended, if not by 

 disease, certainly by a loss of physical fitness, and this 

 loss is especially seen amongst the working class, viz. 

 horses. 



SOURCES OF WATER. 



The original source of all water is rain. It makes no 

 difference whether the water is bubbling up from the 

 bowels of the earth, or running in a brook, it was originally 

 obtained from the clouds. Eain on reaching the earth 

 behaves as follows; — it either percolates, or depending 

 on the configuration of the ground it runs off to the 

 nearest channel and thence to streams and rivers, or it 

 evaporates. 



As a rule two, sometimes three, of these processes are 

 operating at the same time. The amount of percolation 

 depends upon the porosity of the soil and the time of year ; 

 the proportion which runs to brooks and rivers depends 

 upon the impervious nature of the soil and the slope of the 

 ground ; the amount evaporated depends upon the time of 

 year and the temperature of the air. 



In sand and gravel considerable percolation occurs, as 

 much as 90 per cent, of the rainfall may thus be disposed 

 of ; in chalk 37 per cent, may percolate, in new red sand- 

 stone 25 per cent., in magnesium limestone 20 per cent. 

 The portion which percolates is returned to the surface by 

 springs, wells and borings. 



As the water passes into the earth it is constantly moving, 

 and traversing the cracks and fissures which exist in the 

 deeper formations. It also absorbs carbonic acid, as the 

 air in the earth is many times richer in this gas than 

 water. By dissolving carbonic acid, the capacity for attack- 

 ing and dissolving much of the mineral matter it meets 

 with is greatly increased. The original water as it reached 



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