Page:Popular Science Monthly Volume 91.djvu/745

 A Bullet That Flies Like a Comet

��Emitting a stream of sparks, it informs its senders of its direction and point of impact

ET the good rifle shot, or the officer in charge of a company, see the flight and strike of the first bullet or so — and those that follow will strike the mark because immediate correction in the sight-setting can be made. It is embarrass- ing when the enemy selects a ground that will not show bullet impact, such as turf or low weeds or damp soil from which no puff of dust will rise.

Wherefore the tracer shell for field guns and small arms. If you can make a shell or bullet display a trail of smoke by day or of fire by night like a comet, you can easily trace it to its ultimate destination and alter the sights accordingly. The shell of the field gun lends itself most readily to the installation of smoke and fire-making machinery. The trouble is that the weight and the weight distribution and the balance of such shells are quite likely to be different from the high explosive or shrapnel missile, and so the tale told by the tracer missile does not necessarily apply to the real deadly missiles you want to fire.

An Englishman, George T. Revill, patents what he terms an "incendiary bullet" for this purpose — the term has nothing to do with setting fire to the barn of a man you don't like, but merely to a bullet to display fire during flight.

This tell-tale missile has a compart- ment with a narrow bottle-neck pas- sage filled with gasoline or gunpowder. As a lighting device the inventor uses a coiled spring and a wheel with projec- tions to rub over a flint and produce sparks hot enough to ignite the powder or gasoline. The powder, confined in its chamber, is arranged to burn slowly a la sky-rocket, emitting a stream of sparks for the instruction of the firers of the missile. The gasoline is backed up by compressed air contained in a compart- ment ahead of it. The air drives out the gasoline in spray, which in turn takes fire and forms a comet-tail.

Another modification has an incandescent

���The bullet contains a pow- der chamber in which the powder burns slow- ly as in a sky-rocket

��burner to light up the course of the missile. The inventor terms these projectiles bullets, but as bullets are missiles for small arms and not over .30 inch across, the installation mentioned seems cumber- some for a bullet of this size. To in- sert all this mechanism in place is a job of microscopy worse than engraving the

��Compressed j-air chamber \ir inlet

I Powder or 'i-petrol Wheel -Powder outlet

��Cross-section of the fire-display bullet. As a lighting device, the inventor uses a coiled spring and wheel with projec- tions to rub on flint to make sparks

��Lord's Prayer on a ten-cent piece. The inventor probably means shells for artillery.

What several inventors have turned out, and what is really needed, is a practical smoke-trail bullet for rifles, to show its point of impact. The puff of smoke from shrapnel does away in day- time with any necessity for a device to show its flight ; the patent referred to here is for night-firing alone.

��The Best Night Light for

the Sick Room Is a Salted

Candle

FOR a light to be burned all night, there is noth- to the old-fashioned candle it is salted. The salting process consists simply in pouring a little salt into the hollow place around the wick after the candle has been lighted.

��ing superior especially if

��Those of us interested in science, engineering, invention form a kind of guild. We should help one another. The editor of the POPULAR Science MONTHLY is willing to answer questions.

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