THE IRRIGATION AGE. 187 



ity than the water supply will be put in to work on a drive well point, 

 with the result that an unusually heavy load will be put on the mill, 

 especially when the mill is working in high winds. As soon as it has 

 become apparent that the cylinder is too large for the water supply, 

 stop the mill and change the stroke from a longer to a shorter one. 

 Should this not be enough to bring the demand of the cylinder to an 

 amount as small as the supply of water, then regulate the mill to run 

 at a slower speed, and thus avoid injury to the pump and wind mill. 



RESERVOIRS SLOPE OF EMBANKMENTS AND PUDDLING IN SANDY 



SOIL. 



Reservoirs should have embankments 8 feet high, measuring from 

 the outside, arid be of such measurements in length and width as will 

 give capacity enough for 24 hours' pumping, when the mill is working 

 at its maximum. 



Mistakes are often made by trying to use a reservoir spread over 

 too much ground, and having the embankment too low. Smaller res- 

 ervoirs with higher embankments are the best. The inner walls 

 should have a slope of 30 degrees, or about 3 foot raise in 5, and the 

 outer walls a slope of 60 degrees, or about 4 foot raise in 3. 



When the material used for making reservoirs contains a large 

 proportion of sand, it is necessary to obtain good black soil or the de- 

 posit from ditches to use for surfacing the bottom and inside slope of 

 embankments, so that when puddled the reservoir will not leak. There 

 should in all such cases be enough good black soil or deposit from 

 ditches to cover the surface 6 inches in depth. 



To puddle reservoirs where there is a large proportion of sand in 

 the material used, the best way is to follow instructions given in 

 our January issue, but instead of using teams with drags or barrows 

 after water has been turned into reservoir and the surface thoroughly 

 wet down, then turn water off and allow the surface to dry to that de- 

 gree that a horse when led into it will sink to the top of the hoofs in 

 the mud. Then employ as many horses or other animals as conveni- 

 ent to tramp the mud into a solid floor, which will cause the reservoir 

 to hold water very well. 



COAL TAK AND PITCH. 



A correspondent of the Country Gentleman gives the following 

 method for cementing reservoirs with coal tar and pitch: 



After the embankment is made, it and the bottom of the tank 

 should be tramped down hard and allowed to settle some days. Then 

 the surface should be smoothed off with hoes and brushed out with 

 brooms until it is as smooth and clean as possible. The inside surface 

 is now to be covered with common coal tar and pitch one barrel of 

 tar and fifty pounds of pitch will be needed for every 300 square feet, 

 or nine barrels of tar and 450 pounds of pitch for a 40 foot tank, four- 



