104 BOTANICAL GAZETTE [august 





quality, that is, the germinating power, of the seeds in which one 

 may be interested, a quicker method is desirable for every reason. 

 Not only is the economy of time desirable, possibly for pecuniary 

 reasons, as in the case of a seed-buyer, but also there is less danger, 

 in briefer exposure, of injury or loss from fungous or other enemies 

 of the seeds under examination. One of us has shown that, by 

 using silvered Dewar flasks as calorimeters, one may quickly deter- 

 mine that heat is liberated in the germination of seeds, and has sug- 

 gested that there may be such differences in the heats liberated by 

 seeds of different ages that one may use these as indicators of age 

 and germinating power or viability. 5 The following experiments 

 were begun in order to test this idea, and they were continued with 

 other and older seeds in order to prove its correctness. 



The material used in our experiments came to us through the 

 courtesy of Professor R. A. Moore, of the University of Wisconsin, 

 Professor E. J. Wickson, of the University of California, and 

 Professor L. H. Pammell, of the Agricultural College at Ames, 

 Iowa, whom we take this opportunity of thanking for their 

 prompt and generous response to our request for seeds of known 

 and considerable age. 



Method 



method 



Some of the details, 



however, as applied to this particular investigation, should be 

 described now. We used silvered Dewar flasks, some made by 

 Burger of Berlin, others not so good, of about 250 cc. capacity. 

 Most of the flasks were round-bottomed, but a few contained a 

 small drainage tube opening into the bottom of the flask. There 

 are differences in the efficiencies of the different flasks even of the 

 same good make and pattern, but. as will appear later, there are 

 great differences between good and bad flasks as insulators. These 

 differences can be ascertained, without destroying the vacuum of 

 the flask, only by using them under constant temperature. 



We were fortunate enough to have a convenient constant tem 

 perature chamber. This has been sufficiently described before. 6 

 A maximum-minimum thermometer was taken into the room, but 



*Peirce, G. J., A new respiration calorimeter. Bot. Gaz. 46:193-202. 19 08 ; 

 also The liberation of heat in respiration. Box. Gaz. 53:89-112. 1912. 



6 See Peirce, Bot. Gaz. 53:90, 91. 191 2. 



