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 13
n the Rtrlng,C, which allows the weight. B, to fall amipull the brass spring against the iron |E, which closes the circuit ami rings thebell that is in the house. If desired, the Btring can bo stretchedback and forth under the roof several timesor drawn through any place that is in dan-ger of… … Automatic Circuit-Closing Device Experiment with Spool and Card shown in the sketch. Then blow throuphthe spool and it will be found that the cardwill not be blown away but will remainsuspended without any visible support. Thisis explained by the fact that the air radiatesfrom the center at a…
Handicraft · Amusements
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