PERFECTING THE DETAILS. 203 



supporting the tilt box, so as to be stationary. As will 

 be obvious, e, a, c, li and d are movable, but /, g and i 

 are immovable. Two ordinary furniture caster wheels, 

 Fig. 112, travel on the upper side of a, and another pair 

 roll against the under surface of a, the shelf swinging 

 and rolling back by its own weight after a stroke. If 

 the shelf is one hundred and fifty feet long, or more, it 

 should be widest nearest the hammer, and as you go 

 towards the farthest end and the jar is less, each suc- 

 cessive section board should be narrower. Begin with a 

 board ten or twelve inches wide, and diminish to a width 

 of five or six inches. In case of a shelf over a line of 

 exercisers one hundred and fifty feet long or upwards, 

 the boards must not only be narrow as you approach the 

 end of the shelf furthest from the hammer, but they 

 must be hung so as to be slanting. When they are fas- 

 tened together put wedge-shaped cleats between, so that 

 each board shall be slightly steeper than the preceding 

 one. Figures 113 and 115 show these cleats and the 

 varying slants of the boards, e being a slender iron bar 

 firmly attached to the boards, the same as e in Fig. 111. 

 This bar is not absolutely indispensable unless the shelf 

 is extremely long. It is not to strengthen the shelf, 

 but, as previously remarked, to transmit the jar of the 

 hammer better than wood alone will do. In Figs. 105, 

 113 and 115, the boards, are foreshortened in the cuts 

 so as to occupy moderate space and show the idea of the 

 cleats and the slanting position, but the reader must 

 imagine them to be, in practice, ten, twelve or fifteen 

 feet long each. 



If a feed shelf is indoors it is supposed to need no 

 cover to protect the grain from pigeons, sparrows, stray 

 fowls and rain. For outdoor use, however, fasten shal- 

 low boxes upon your shelf, with lids opening upwards, 

 and a slot cut through both the shelf and the bottom of 

 the box at one side, as in Fig. 109, only the cut gives a 



