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Page:Popular Science Monthly Volume 89.djvu/688

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��Popular Science Monthly

���There are no exposed levers or flywheels and the motor is enclosed in a casing

A Tiny Portable Hoisting Engine of Dual Power

ADliMIM'TIVK Init powerful hoist- ing engine that handles loads of one thousantl ixunids or less o\er distances of sc\eral hundretl feet has been de- signed recent!>'. It is ojicratet' either by steam or by com- pressed air.

This little iioist, said to be the smallest prac- tical one of its kind, has the additional fea- ture of safety, ha\ing no exposed levers or flxAvheels. 1 1 is design- ed for rough ser\ice, particularK- for use in mines and cjuarries. It is portable, and can be mounted almost anywhere — clamped to a pipe (jr cokinni or bolted to the wall.

Both for safet\- and motor is contained in brake is a band-l\pe operated by a worm — a screw with a long pilch — to constrict it, so as to give greater holding power.

��Why the Rain Follows the Thunder and Lightning

WHY does a hea\y downpour of rain often follow a clap of tiiunder? Xot, as is popularly be- lie\ed, because the thunder jostles the cioiid particles together into raindrops. In the \iolenl turmoil between the pi)siti\e and negati\e electricity in a tiiiindercloud there will be places where the production of drops, by con- densation, and their subseciucnl break- ing up proceeds more rapidly than elsewhere. Hence in these places tliere will be more drojis to fall as rain, and also more electrification, the rainfall occurring about the same time as the Hash. We have, then, starling toward the earth at the same lime, light, sound, and raindrops. The light, traveling at a speed of about i,S6,ooo miles per second, reaches us almost instantly. The sound travels far more slowK" — about 1,090 feel per second — but the rain falls much slower still. Thus we obser\e, first, the light- ning, then the thunder, and then rain.

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��A Tobacco-Can with a Roll of Cigarette Papers Attached to It

FOR the conxenience of smokers who prefer to roll their own cigarettes, Bertram .A. Rose, of Fort Worth, Texas, has invented a cigarette-paper holder attached to the under ide of a tobacco-can co\-er. When he wants to roll a cigarette the smoker jnills the paper out- ward and downward Irom its position on the roller, and then tears it oil for a long or short smoke b\' us- ing the outiT edge of I he lid as a cutter.

In pulling the paper otitward and down- ward o\er the edge of the lid the "roll" is t.iketi out. The paper m.i\' be ])erforaled to facilitate the tearing and cutting oiiera- tion, but the in\entor relies m.iinly upon the outer edge of the lid for cutting each piece of jiaper as it is pulled from the roll anil pre.sse<l against the tin.

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