274 NATURE-STUDY REVIEW [12:6-Sept., 1916 



EXPERIMENT ONE 



In this experiment we proved that air pressure was a real force 

 and that it would press in to fill a vacuum. Our apparatus was : 

 A pint milk bottle, a hard-boiled egg with the shell removed, a 

 match and some paper. The paper was lighted and then dropped 

 into the bottle. After the heat had expelled some of the air with- 

 in, we placed the egg in the mouth of the bottle. It quickly elon- 

 gated and within a few minutes had slowly dropped into the bottle. 

 It may take fifty minutes or three seconds for this experiment — 

 all depends on the flame given off by the paper. 



We believe that we showed by this experiment that air pressure 

 was an active force and that it acted most rapidly when the vacuum 

 was most perfect. 



EXPERIMENT TWO 



We sought in Experiment Two to prove the same principle as 

 in Experiment One, only by a different way. Our apparatus con- 

 sisted of a wine glass, some bits of paper and a match. We called 

 it "The Cupping Experiment." I first bared my forearm and then 

 dropped the bits of lighted paper into the wine glass. After they 

 had burned for a few seconds I suddenly inverted the glass on the 

 forearm. The bits of paper ceased burning immediately since the 

 supply of air was exhausted. While the class watched my fore- 

 arm both they and I were greatly astounded to see the flesh of the 

 forearm rise fully a half inch into the glass. Fearing the rupture 

 of a blood vessel. I attempted to pull the glass off but found that 

 it resisted my efforts. After several violent pulls I accidently 

 raised one of the edges of the glass and it came off without any effort. 

 Afterwards, I used a piece of salt pork instead of my forearm and 

 found that the results were just as good. I then explained to the 

 class that the cupping glass was formerly used to draw blood to the 

 surface and to draw pus from gangrenous wounds. 



EXPERIMENT THREE 



This is a chemical experiment. By it we proved that combus- 

 tion ceased when the supply of air was exhausted. Our apparatus 

 consisted of a pint and a quart milk bottle, a candle, and a match. 

 When the inverted pint bottle was placed over the lighted candle, we 

 found that the flame expired in ten seconds; but when the quart 

 bottle was used, the flame burned for twenty seconds. Thus we 

 established the fact that the life of the flame was proportional to 



