and set this over a square hole cut in the roof for this purpose. The ventilator should project at least one foot and a half above ground, and the top or vent be protected by wire-netting or cross-pieces, nailed on as shown in Fig. 82. Now spread small brush over the boards, and dry leaves or straw over the brush, then shovel the dirt back in the excavation until the club-house is entirely covered; pack the soil firmly all around the house, leaving only the top of the ventilator and the front door uncovered. [Illustration: FIGS. 79-83.--Cross-Section of House.] When all is finished to your satisfaction, conceal the ventilator by brush or transplanted weeds or shrubs, and scatter grass and clover-seed over the new earth. Make a strong door, after the plan in Fig. 81, and fasten it on the front entrance with good hinges and a padlock, and place some brush or growing shrubs in front of the door. After the Grass Begins to Grow there will be little to cause the passers-by to suspect that the green bank conceals a room well supplied with chess, checkers, boys’ books, and everything to make a boy happy. Dangerous Caves. There is an impulse implanted in all boys, which impels them to dig caves in every convenient bank, and these caves are always more or less dangerous from their liability to cave in upon the youthful miners. It not infrequently occurs that sad accidents do happen to youngsters, who, on account of lack of instruction, attempt to make underground retreats in some sandy bank, by boring a hole in the face of the hill. If, however, they make an excavation as here directed, and illustrated by Figs. 76 and 76a, their parents need feel no apprehension, for there is no more liability to accident than if they were digging in the home garden. Many of these houses have already been constructed. CHAPTER IX. A BOYS’ CLUB-HOUSE ON THE WATER. We cannot all be Robinson Crusoes, and real desert islands are scarce, but with a little work we can build artificial islands, upon which Robinson Crusoe cabins of novel designs may be erected, and by forming Crusoe-Clubs, consisting of as many members as the island homes will accommodate, we shall have plenty of company. The President of such a club may be called “Robinson Crusoe”; the Secretary, “Man Friday”; the Treasurer, “The Goat,” and the Captain, “The Parrot.” In selecting a site for the club-house, choose a bar or shallow place in some small lake or pond. Not only is the Foundation of the Club-House Submerged, but it must be built under water, and every foot of water adds to the difficulties. The following plans are made for foundations to be laid in water not much over waist-deep. For the convenience of the draughtsman, the bottom in the diagrams is supposed to be level. The Building Material