41 
the results are most marked. It is difficult to design an appa- 
ratus which would measure the full amount of energy exerted by 
such seeds when dees but the following method will yield a 
fair conception of the 
A manometer is me an a glass tube bent into the form of 
aU. Anair tight stopcock is fitted to one arm of the tube, and 
the other i is bent again until its free end is pointed in the opposite 
other lower end of be is now thrust through a hole in the 
screw cap of a glass or metal jar, and this portion is filled with 
wi by minute metal tube. Next a st rubber 
place in the center of the jar and peas are poured in eae it 
until the jar is completely filled. The cap is screwed on the 
jar set in a larg sel of water. The liquid enters through a 
second hole in the cap and is absorbed by the e fi 
walls of the jar prevent much expansion outwardly, and the 
swelling peas can only crush the bulb driving the water which it 
contains up into the glass tube, which is already fille he 
pressure of the column of water in the b ube forces the 
mercury up into the other arm compressing the air which it con- 
tains, a state of affairs to been ni ig. 2 e actual 
amount of pressure at any time computed by Mariotte’s 
law. e volume of a gas varies inversely with the pressure 
shows the pressure directly. Thus if a column of a inche: 
long is compressed to § inches, the pressure is 10/5, or 2 atmos- 
pheres. 
An iron cylinder was filled with peas and fitted as in figure, 
No. 2 on February 23d, and the following observations made : 
Time. Length of column of air. 
9:30 AM 
10 ‘s 5.90 
