Passageway.
To make the frame for the underground hall or passageway, first nail Q, S across the door-jambs, to form the top to the doorway, after which put in the supports Q, R and S, T. Next build the frame U, V, X, W, and join it to Q, S by the two pieces, Q, U and S, V, and put in the middle frame-support marked Z, Z, Z, Z.
Fig. 77.—The Frame.
The passageway should be about six feet long, and the front doorway (U, V, X, W, Fig. 80) of just sufficient size to enable you to creep through with comfort. The bottom-piece, W, X, can be nailed to a couple of stakes driven in the ground for that purpose. The next thing in order is the floor, and to make this firm you must lay a number of two-by-fours, parallel to B, D and F, H and see that they are level. You will need a number of shorter pieces of the same material, to run parallel to F, H and W, X for the hall floor, as may be seen in Fig. 79. Across these nail your floor securely, as shown in Fig. 79.