800 



Popular Science Monthly 



The Construction of a Small 

 Concrete Com- Crib 



THE roof of this corn-crib is made of 

 lumber and the side walls and floor 

 are of concrete. The walls consist of 

 concrete fence posts — the ordinary kind 

 with 3-in. tops and 6-in. bases. The 

 foundation and floor of the building are 

 of concrete mixed in the proportions of 

 I part cement, 3 parts of sand and 

 5 parts gravel or stone broken in pieces 

 not larger than 2 in. in any dimension. It 

 is a permanent crib, 

 reasonable in price. 



CONCRCTE. FLOOR & FOOTING^^ 



Corn-crib made with concrete posts for 

 the side walls and with solid concrete floor 



The posts are anchored at the bottom 

 to the concrete and at the top are 

 securely clamped together with a box- 

 plate made of three 2 by 6-in. pieces 

 bolted together every 4 ft. over the top 

 of the posts. Along the front side of 

 the crib there is a short studding about 

 2 ft. long which supports the roof and 

 makes a convenient place where the grain 

 may be thrown in the crib. The rafters 

 are spiked to the plates and are set on 

 2-ft. centers. Across the top of the posts 

 from plate to plate a cross-tie is run 

 from each rafter. This makes the crib 

 solid and will prevent the sides from 

 spreading. 



I n the ccn t cr of 1 he crib criss-crossbraccs 

 of wire should be put in, twisted taut and 

 fastened to bolts at the foundation line. 



Cover the roof with shiplap for sheathing, 

 making a tight and smooth foundation 

 for the three-ply asphalt-and-felt pre- 

 pared roofing material which is laid 

 lengthwise of the building. 



The posts should be of a l-to-3 

 mixture of cement and sand made into 

 a sloppy consistency before pouring it 

 into the forms. One sack of cement 

 will make about 8 posts, weighing 90 lbs. 

 each. There should be three )^-in. 

 round steel rods placed in the center of 

 each post to reinforce it. For an 

 8oo-l)Ushel crib of a size 9 ft. by 32 ft. 

 the following amounts of materials will 

 be required: 



13 barrels cement for floor and founda- 

 tions 

 6 cubic yards of clear sand 

 10 cubic yards of coarse gravel 

 80 concrete posts 

 2 dozen bolts 5^ by 8 in. 

 300 ft. of 2 by 6 in. material for box- 

 plates 16 ft. long 

 100 ft. of 2 by 4 in. material for cross- 

 ties 9 ft. long 

 150 ft. of 2 by 4 in. material for rafters 



12 ft. long 

 40 ft. of 2 by 6 in. material for studding 

 2 ft. long 

 450 ft. of shiplap sheathing lumber 

 4 squares of three-ply roofing felt. 



Experiments with Antennas 

 of Varying Lengths 



AT some wireless stations very inter- 

 L csting results have been secured by 

 providing a number of single-wire aerials 

 of various lengths and extending them in 

 difierent directions from the operating 

 room. By the use of single-pole, double- 

 throw switches these may be connected 

 to the receiving tuner or directly to the 

 ground, or left open-circuited. Various 

 combinations are found to give good 

 results in receiving from particular 

 stations, depending u(ion the tlirection 

 and wavelength of transmission. 



It has sometimes been found \aluable 

 to ground one wire through tuning in- 

 ductance wliile receiving on an entirely 

 separate aerial. 



Those of us interested in science, engineering, invention form a kind of guild. 

 We should help one another. The editor of The Popular Science Monthly is 

 willing to answer questions. 



