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AGRICULTURAL ENGINEERING 



side locations, as they are easier to erect and are cheaper. 

 Cypress is considered one of the best woods for tank construc- 

 tion, and may be expected to last 15 to 20 years. 



Tanks are sometimes placed in or on buildings, but great 

 care should be taken to determine whether or not the building 

 is sufficiently strong for the purpose. Water in quantity is 

 very heavy: 300 gallons will weigh 2,500 pounds, to which 

 must be added the weight of the tank. Tanks placed in 

 residences have often caused settling of the framework under- 

 neath and consequent cracking of the plastering. In barns 

 they can be supported to better advantage. 



Cement or concrete towers and tanks are coming into use 

 and, when properly built and reinforced, there is no reason 

 why they should not be economical. 



The masonry silo provides what is seemingly a good loca- 

 tion for a water tank for a farm water supply. The tanks 

 themselves may be built of masonry if properly reinforced, 

 and plastered with cement plaster on the inside. The bottom 

 of the tank can be easily constructed of concrete, if built in a 

 conical form and reinforced to prevent cracking at the base. 



The Air-Pressure System. The pressure tank, or pneu- 

 matic system, consists of an air-tight tank, a force pump, 



Fig. 305. An air pressure or pneumatic water supply system. 



