8 July, 1907.] 



Use of Concrete for Silos. 



407 



strengthening was made. Two strands of No. 12 gauge hard steel wire 

 were laid on the top of each ring at every course — four wires to each course 

 — and built in with the blocks. This method of reinforcement is preferable 

 as the wires are not subject to contraction and expansion to such an extent 

 as the hoops in their exposed position. Apart from the chance of cracks, 

 neither of these precautions appears necessary, the concrete being strong 

 enough to v/ithstand the pressure of the silage. It is advisable all the 

 same tO' reinforce the silo as described. Such a course is even more essen- 

 tial in the case of a brick silo. 



In the Orphanage silo, about 13 cubic vards of gravel and sand to- 

 gether, 13 barrels of cement, and 250 feet of hoop iron with the necessary 

 lugs and bolts, were used; about 2,000 feet of No. 12 gauge steel wire 

 might be used in preference to the latter. The wire will weigh about 



THE CONCRETE SILO SHOWING HOOPS AND PORTHOLE. 



3 cwt. The porthole doors will require two sheets of 6 by 3 iron (No. 24 

 gauge), and 50 feet of 6 by i timber. The roof may be of any suitable 

 design. About the cheapest roof in iron will need 16 sheets of 8-feet 

 galvanized corrugated iron and 100 feet of 4 by 2 timber. Timber for 

 scaffolding, put up inside the siloi as work progresses, is necessary, but is 

 available for uise elsewhere on completion. With these quantities and 

 the rates of work quo.ed abo\e, the cost on a farm of a concrete silo mav 

 be estimated. 



The silo has not } et been filled ; the past summer was an unfortunate one 

 for fodder crops and the maize relied upon to fill it turned out badly. 

 It will, however, be easily filled next spring. Lime washing is essential 

 in the concrete as well as in the iron silo. 



