520 Reading-Coltrse eok Farmers. 



Or, the ordinary field stone picked up on the farm may be dumped 

 year after year into the brook at the point where it is decided to form the 

 dam and the result will be a solid structure, which, if not tight at first, will 

 soon become so from the accumulation of fine silt which will wash into 

 the pile of stones. It may be made tight at once by planking the up 

 stream side. 



The earth dam is best made with a core wall, — a thin stone or con- 

 crete wall, eighteen inches thick, running in a trench well down into the 

 foundation and extending along the center of the dam well into the banks 

 on each side. If the core wall is not built, special care must be taken to 

 tamp the dirt well and to avoid any possibility of erosion by water flowing 

 over the top. The question of overflow is very important, for if a flood 

 comes over the top of such a dam it is almost sure gradually to eat it all 

 away. If possible, then, the overflow of such a dam ought to be taken 

 around the dam in a new channel cut through the solid bank siJeways, 

 either back into the same stream or even into another valley. Otherwise 

 a special provision for the waterfall must be provided. This may consist, 

 if it is a. core wall, of paving with cobble stones up and down both slopes 

 a sluice-way for the running water. This paving must be well laid, the 

 stones well set into the bank and the sides as carefully protected as the 

 bottom. The size of this opening left for the flood water may be roughly 

 calculated from the old rule to make the opening two feet deep and three 

 feet long for every loo acres of the area draining to the reservoir. 



Timber also may be used for the dam and to form the sluice-way. 

 However, unless the timber is to be always under water, it will decay in 

 a few years so that unless both labor and time are very cheap, it is more 

 economical in the long run to use either masonry or earth. 



The pipe line from the spring or reservoir to the house may be of 

 iron pipe, lead pipe, or wood pipe or sewer pipe. If the height of the 

 spring is loo feet above the highest fixture, then a three-fourth inch pipe 

 would be sufficient, and this is the sm.allest size that should be used in any 

 case. If, however, there is only ten feet above the fixture, the pipe ought 

 to be larger and it may be that a sewer pipe four inches in diameter can 

 be used to advantage. Wood pipe made of bored logs was used in years 

 gone by, but now it costs more than iron pipe. If the ground slopes 

 gradually from the spring at the start, then the sewer pipe is particularly 

 well suited, and it can be bought for about six cents per running foot, the 

 same price as three-fourth inch wrought pipe. If the joints of the sewer 

 pipe are carefully made with good cement and the dirt is well tamped 

 back around the pipes, it will stand an internal pressure of about twenty- 

 five pounds per square inch, and, with care, it might be used for an entire 

 line; but it is always safer to have the lower end, where the pressure is 



