Amateur mechanics ... a book for old and young who like to make things .. (1907)
Popular mechanics magazine, Chicago. [from old catalog] · Chicago, Popular mechanics · leaf 31
of Coherer as shown in the sketch. When the elec-trical waves strike the needle the conduc-tivity of the filings is established and aclick is heard in the receiver.—Contributed3y Carl Formhals, Garfield. 111. An easy wray of making a controlling andreversing device for small motors Is as fol-lows:… … Reverse for Motor a copper brush (D) to extend <>ut about an inch. On the upper side at the same end,nail another brush (E) so that it projectsat both sides and is bent down to the levelof the end brush. Then on the board puta semi-circle of brass-headed tacks as shownat F, leaving a small…
Handicraft · Amusements
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