Page:Popular Science Monthly Volume 90.djvu/471

Rh fastened together and held in place by two pieces, or strips, 3 in. wide by i in. thick. One piece is nailed along the top and the other along the edge on front and sides.

The gates are made from 2-in. square material 6 ft. high, swung between posts made of studs. At the top of each gate is placed another 3 by 1-in. strip; as shown in the illustration. Each pen is provided with a running- board on each side. This is 6 in. wide and 1 in. thick, placed 5 ft. from the ground where it is carried on wooden brackets The whole fly is covered with wire netting, preferably of 1-in. mesh. The 2-in. mesh is good but it allows sparrows to get in.

This house, if properly built, will accommodate 200 pairs of breeders with ease. The cost should be very moderate and it has every good feature which could be demanded in a modern squab house.

Locating Electric Conduits in Old Walls

HEN necessary to find a conduit for repairs or removal, the tearing up of flooring or plaster is un- avoidable if the location is not marked. To do this quickly and with little trouble, use the or- dinary compass. Locate the cable as near as possible, then place the compass close and keep it on the move until the needle will not deflect in either direction. The cable will be found directly beneath the compass when the needle stands in this position. It is necessary to have a current flowing through the wires in the cable to produce the magnetic field for moving the compass needle as there is nothing in the cable sheath to cause it to turn, most sheaths being made of insulating materials and not metal.

'A Concrete Letter Box in the Form of a Post

HIS concrete letter box is like a large concrete fence post with a hole in the top and a hinged lid to cover the opening. It has been used for years. It does not leak, it looks good, and will last forever.

Make the molds of wood. The under- ground portion of the letter box should be at least two or three feet deep to a solid footing and below the frost line. The outside dimension of the square concrete is 12 in. and it need not taper. If desired, the exposed corners may be beveled with an edger. The hole in the top is 8 in. in diameter and 14 in. deep. A heavy bolt is placed in one corner of the top of the post so that the lid can be swung upon it. Reinforce the corners with ⅜-in. round steel rods running the full length of the letter box, which is about 3½ in. above the grade line.

In the mixing of the concrete, if un- screened "bank run" gravel is used, it should be mixed in the proportion of one to four. Crushed rock or screened gravel and coarse sand are better for concrete work, and if such materials are available use a one-two-four mixture for the buildings of this simple but durable letter box for the farm. Tamp the sides of the forms lightly so as to remove the air bubbles in the concrete and force the gravel towards the inside. Else an old piece of 8-in. drain tile for making the hole in the top which will hold the mail. The cover is made of concrete and is reinforced with a wire netting. A round metal pin fastened in the cover fits in a hole in the post top to provide a way for swinging it from over the hole.