368 ENGINEERING ON THE FARM 



should provide about two days' supply. A galvanized iron 

 pan under the attic tank will care for sweat and overflow 

 if provided with an outlet to the sink or the outside. As 

 water weighs 62^ pounds per cubic foot, which is equivalent 

 to 7>2 gallons, care must be taken to provide supports adequate 

 for the weight of a tank of water. Two hundred fifty gallons 

 occupy about 36 cubic feet and weigh a ton. This added 

 weight on the attic floor will cause settling in any ordinary 

 house. 



A wood or iron tank elevated in one end of a barn is 

 subject to leaks and sweating and is, therefore, not very 

 popular. A tank in either house or barn is subject to 

 freezing, and insulation makes it very difficult to locate and 

 repair leaks. Probably a reinforced concrete tank, with a 

 commercial insulation, or with a light wood jacket, pro- 

 viding space for 8 to 1 2 inches of dry mill shavings, would 

 meet the requirements. The chief objection to this is the 

 enormous weight of the tank itself. The tank is not high 

 and can be amply supported. 



A concrete, clay-block, or masonry silo offers oppor- 

 tunities for an elevated tank which is well taken care of 

 as regards support and reasonably well provided for with 

 respect to freezing from below. It does, however, need 

 protection at the sides and on top. To supply this, it 

 becomes necessary to protect the insulation from the weather, 

 which is not necessary when the tank is under the roof of 

 the barn. Any kind of insulation, other than cork, will 

 absorb moisture and when thoroughly wet is practically 

 worthless. 



Where ground-level conditions will permit, the most 

 satisfactory and cheapest installation may be made by 

 means of a concrete cistern built at an elevated point. It 

 is essential that this elevation be sufficient to force the 

 water to the highest point desired. The distance of the 

 cistern should usually not be over 300 feet, as the friction 

 in a length of pipe greater than this will be such as to reduce 



