Popular Science Monthly 



631 



A Burglar-Alarm for the Unprotected 

 Chicken-House 



CHICKEN-FANCIERS and poultry- 

 farmers will be interested in an 

 electric alarm which is set ringing by 

 thieves. The favorite means of entrance, 

 provided the door is securely locked, is 

 through the windows of the coop. The 

 installation of the usual type of burglar- 

 alarm involves an outlay for costly equip- 



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When the chicken thief breaks the thin 



wires covering the window, he opens the cir- 



cvdt, the buzzer-armature drops, and the 



alarm bell rings 



ment. The apparatus to be described is 

 inexpensive, and may be easily installed. 



A row of wire nails about 1'" apart 

 should be driven into the window-frame 

 above and below. Fine cotton-insulated, 

 magnet-wire should be strung up and 

 down over the two rovv^s of nails, as 

 shown in the diagram. The two ends 

 should be led to a gravity cell, and also 

 to the magnets of a buzzer. The arma- 

 ture of the buzzer should be disconnect- 

 ed, but not removed, as it will have an- 

 other use. By consulting the diagram of 

 connection it will be obvious that if the 

 wires over the window are intact, the 

 armature will be drawn down upon the 

 magnet-cores, away from the contact. 

 Wires connected with a bell and dry bat- 

 teries in the house — the distance makes 

 no difference — should be brought to the 

 armature of the buzzer and to the con- 

 tact that touches it. 



The operation is as follows : When a 

 marauder attempts to enter the window, 

 he breaks the wires — which he assumes 

 to be strings — with a sweep of the hand. 

 The circuit, suddenly opened, allows the 

 armature of the buzzer to fall back 

 against the contact. This closes the bell 



circuit and causes the bell to ring in the 

 house. If there are several windows in 

 the chicken-barn, the wires covering all 

 of them should be connected in series. 

 Gravity or blue vitriol batteries should be 

 used for the magnet circuit. 



How to Shingle Without Leaving 

 Nail-Holes 



THE illustration will show how a 1' 

 by 6' straightedge, or longer, can 

 be used to lay shingles 2>/-^' by 8" or 2" 

 by 7", according to the weather, on the 

 side of a building, without nailing the 

 straightedge on to the shingles and thus 

 leaving unsightly holes. Any blacksmith 

 will make four hooks out of V2'' by %" 

 iron and twist them so that the shank 

 can be screwed on the ends of the 

 straightedge, and so that the hook part 

 will extend down and under the last 

 course of shingles, as indicated in Fig. 2. 

 The iron is drawn out to 1/16'' thick- 

 ness, and the spurs on the hook part are 

 made by cutting a V in the hook while 

 it is hot and turning it back and filing 

 it down to a sharp edge. This spur holds 

 the straightedge in place. It is well to 

 have this part of the hook offset clear of 

 the ends of the straightedge (Fig. 1). 

 x\fter the straightedge is in place, a 

 slight tap of a hammer over the shingle 

 will drive the spur into the shingle under- 

 neath. No holes will be left to mar the 

 face of the work. A slight jerk will pull 

 the spur out and the straightedge is then 

 ready to be used for the next course. 



Details of a shingling device which keeps 

 the edges straight without driving nail- 

 holes into the exposed ends 



