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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