Worst, Edward F. (Edward Francis), 1866-1949, Barber, Harriette, [from old catalog] joint author, Seymour, Marian, [from old catalog] joint author · Chicago, A. W. Mumford and company · leaf 254
FIGURE X.250 While the three classes of levers may be illustrated bymeans of a ruler and triangular prism for a fulcrum it isalso well to encourage older boys to construct a piece ofapparatus by which they may illustrate. In the above fig-ures the power arm may be moved to and fro by removingthe… … FIGURE XI. In the study of sound Fig. XII. will be of great assist-ance. The turning pegs may be purchased at any departmentor music store for a small sum.
Manual training · Paper work · Basket making
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