Water Supply and Drainage 229 



a place should secure land enough to protect themselves against outside contamina- 

 tion. Although the first outlay may be more than the individual cares to carry 

 permanently, yet as a safeguard it is worth its price, and further disposal can be 

 planned for and consummated at such time as public service and the increase of 

 taxes and land valuation make it advisable. 



Of late years the importance of these two has been more and more realised. 

 The engineer makes them his especial study, and the inventive rnind turns more 

 and more to mechanical contrivances for their perfection. 



Water in its normal state consists of two parts hydrogen and one part oxygen 

 gas. These two gases in combination lose their gaseous form and become at 

 once a new substance. This is no sooner in existence than it loses its normal 

 condition by the absorption of foreign matter. Leaving the form of vapour and 

 changing into rain, it absorbs from the atmosphere such purity or impurity as it 

 may contain, and falling on the earth and filtering into it draws in turn from 

 this source such properties as it may dispense. Although water absorbs im- 

 purities, as we have already stated, it also purifies itself by filtration through 

 cleansing soils, which in turn take up the infectious matter. 



As the modern public service is usually constructed under the supervision of a 

 competent engineer, it is fair to assume that it will be perfected as far as knowl- 

 edge and skill can carry it. Much depends upon the natural resources, and even 

 the most skilful engineer is limited in the entire success of his undertaking. A sys- 

 tem may be complete and draw upon water that is, owing to existing conditions, 

 not of the best. With this in mind, it is well for the prospective purchaser to go 

 over the ground thoroughly and assure himself by personal inspection and expert 

 analysis that he is perfectly safe in this direction. 



No country house is desirable as a residence, either permanently or tem- 

 porarily, which has not at least a good well or an unfailing spring of pure water 

 handy, and in such a position as to be free from all danger of contamination by 

 surface water flowing into it, or by impurities reaching its source through porous 

 soil strata. 



The first action of the water falling upon the earth is, in obedience to the laws 

 of gravity, to seek a lower level. This it does by flowing over the inclined surface, 

 or by filtering through porous soil. After leaving the surface of the ground it 

 proceeds until it strikes some impenetrable strata, over which it flows seeking an 

 outlet. Commonly it is this water en route which is the source of supply for the 

 ordinary well, although springs are struck frequently in well digging and the exist- 

 ing spring is converted into a well by excavation. 



Water flowing over an impermeable stratum often reaches a pocket or basin, 

 which becomes filled and thus causes the water to seek an outlet through the surface 

 of the ground. Thus springs are formed. Large springs or small ones in suffi- 

 cient number, coming to the surface in natural land basins or valleys, form ponds 

 and streams. These also receive water from the various watersheds, much to the 

 detriment of their purity. 



It is difficult to judge of the quality of water and its fitness for drinking or 

 general domestic use from the mere facts of looks and taste. A person with no 

 knowledge of chemistry should not attempt to settle this question. It is always 



