Pools and Cisterns 263 



of these pools to furnish water for a hundred 

 head of cattle during a long continued drought. 

 It is difficult to explain why more pools, lakes 

 and fish ponds are not constructed. Possibly 

 the reasons are that there is a prejudice against 

 them, and well there may be, since they are 

 usually so shallow that the water becomes im- 

 pure, and since it is not generally realized that 

 a substantial dam can be erected by the use of 

 earth alone. If it is thought advisable not to 

 allow the animals to go to the pool, it may be 

 fenced, since it is not expensive to lay a {)ipe 

 in the dam, when it is being constructed, on a 

 level with the bottom of the pool, the outer end of 

 the pipe being furnished with a ball and cock 

 to regulate the flow of water into the trough. 



Usually it is not advisable to build cisterns 

 for storing water for barn use, since they are too 

 expensive if built as large as needed. A cow re- 

 quires from forty to eighty pounds of water daily 

 in the summer. If sixty pounds be taken as the 

 average, it will be seen that it would require a 

 cistern of three hundred and fifty barrels ca- 

 pacity to supply a herd of fifty animals for 

 one month. In some cases the water of a stream 

 or well may be so highly charged with the pro- 

 ducts of magnesian limestone as to produce 

 goitre, in which case soft water should be sup- 

 plied for the horses. 



