146 



Hints on Water Supply. 



[JUNE, 



falling in, owing to the saturation of the earth near the bottom. 

 If the trench goes down to more than 5 ft. in depth it may be 

 advisable, especially in loose earths, to provide wood sheeting 

 and cross struts to preserve the sides. 



In cases where springs or streams are depended upon for 

 supplies, gauges should be fitted at a little distance below the 

 spring-point ; by this means the volume of water coming over 

 the gauge can at any time be ascertained. The simplest form of 

 gauge for small streams is the V-notch, which is formed by fix- 

 ing together, exactly at right angles, two feather-edged boards, 

 which are then set upright in the form of the letter V, in the 

 course of the stream, in such a way as to completely dam 

 it, so that all the water which comes down must fall over the 

 V. The feather-edge of the boards is to form the inside 

 of the notch. Then, on the up-stream side of the V, a peg, 

 upon which has been cut or painted inches and their halves and 

 quarters, is carefully driven in close to the edge of the stream, so 

 that the zero mark on the peg is on precisely the same level as 

 the bottom of the opening in the V. The approximate volume 

 of water in gallons per minute for the various depths up to 5 in 

 can then be seen by reference to the following table : — 



Depth of water in 

 inches above bottom 

 of V-notch. 



Fractions of an inch. 



0. 



1 



4* 



1 



2* 



:5 



4' 





2 



3 

 4 

 5 



2 

 61 



103 



3i 

 Hi 



36 

 71 



5i 

 i8| 



43i 

 8i| 



71 

 24 



52 

 94 



| Gallons per minute 

 )■ coming through 

 1 the gauge. 



J 



Thus, supposing the gauge to have been properly constructed 

 and that the water at the first gauging stands at \\ in. up the 

 peg, it indicates a flow of 8 if gallons per minute. If, at a 

 subsequent gauging, the water stands at 3^ in.'jup the peg, it 

 shows the flow to have diminished to 43^- gallons, or a dimi- 

 nution of 38^ gallons per minute since the former gauging. 



Where water from a spring or stream is required to be 

 delivered at a distance, by other than hand or animal traction, 

 the hydraulic ram will in most cases be found to meet all 

 requirements. This useful little machine is, in effect, a self- 



