DECORATIVE WINDMILLS 



at that point of four and one-third pounds a square 

 inch. A consideration of such facts will show that 

 the tank must be strengthened to resist the outward- 

 impulse, and that the strength must increase toward 

 the bottom. 



The tank may be of wood, steel, or reinforced con- 

 crete. When it is of wooden staves, the metal hoops 

 may be provided with turnbuckles, so that they may 

 be tightened at will. The hoops may be placed 

 closer and closer together toward the bottom, to give 

 additional strength. The concrete tank is the 

 favorite, where it can be placed out of danger of 

 freezing. A thin coating of ice will not matter for 

 any sort of tank ; but in cold northern climates, where 

 it is desirable to keep up a satisfactory supply of 

 water for the house throughout the winter, special 

 care must be given to the location of the tank. If 

 it is within the house, there are easy and practical 

 methods of insuring its safety from freezing; and 

 even in cooler locations it may be rendered ' ' safe ' ' 

 by surrounding it with sawdust, or tan bark, or the 

 material most recommended by the experts who have 

 given the subject special study in the locality in 

 question. 



When the tank is placed at the top of the wind- 

 mill and surrounded by a tight, warm enclosure in 



tower design, its elevation in regard to giving an 



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