2100 Needed Inventions |
Contents
Fortunes for Inventors | 1 |
Uncle Sam Calls for WarTime Inventors 8 5 35 | 4 |
The Ten Most Needed Inventions | 5 |
Copyright | |
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airplane alloy alternating current aluminum applied attachment automatic automobile battery better carbon castings cause cheap cheaper chemical chloropicrin circuit coal color construction corrosion cost degrees F designed developed device direct current dollars drill dry cells easily effects efficient electric current electric motor electrical insulation electrolytic eliminate energy engine equipment especial military expensive fibers fountain pen frequency furnace gasoline glass handle heat high voltage idea improved industry inexpensive insulating Inventions marked inventor iron keep liquid lubricating machine machinery magnetic manufacture material means mechanical metal meter method motor needed inventions operation oxide paint paper patent permit pipe plastic plate portable possible powder metallurgy practical present problem produce radio remove resistance rubber selenium simple solder solution speed steam steel substitute surface temperature thing third rail tion typewriter vacuum cleaner vacuum tube wheels window wire withstand