THE UESriRATIOK OF AIM'I.KS. 



89 



Since no exact figures had been obtained showing just 

 how rapidly an apple was changed in composition when 

 stored at an ice cold temperature compared with another 

 apple at 45 degrees and another at summer temperature, it 

 seemed possible to measure the rate by determining the 

 amount of carbonic acid given off by the fruit at different 

 temperatures. The carbonic acid would not show the kind of 

 changes taking place within the cells of the apple; but it 



would be a measure of the rate at which those changes were 

 progressing since the formation of the carbonic acid must 

 be one of the reactions concerned in them. 



A simple apparatus was planned, by which the carbonic 

 acid breathed out of the apples could be collected and 

 measured. The apparatus consisted of a cylindrical copper 

 vessel supported on three legs, and large enough to hold 

 about six quarts. The top of the vessel or can was closed 

 by a circular plate of glass, that rested on a narrow shelf 

 of copper soldered around the inside of the cylinder a little 

 below the top. An inlet tube was soldered into the vessel 



