210 



In a second trial, after turning the peas out of the 

 jar, and again replacing them with a quantity o 

 fresh air, the difference indicated by the thermome- 

 ter plunged in the peas, amounted, in half an hour, 

 to one degree, but, at the end of another half hour, 

 k was only 0.5. The amount of this difference 

 must be expected to vary according to the more or 

 less active manner in which the process is going on ; 

 but the result seems to prove, that, during the pro- 

 cess of germination, a production of temperature ac- 

 tually takes place- The process of malting affords 

 us an example of the same thing. This is conduct* 

 ed by exciting germination to a certain extent in the 

 seed ; and, during the process, a considerable pro- 

 duction of temperature takes place ; so great, indeed, 

 that in certain circumstances, grain improperly kept 

 has even taken fire. From this fact we may con- 

 clude, that during the germination of seeds in the 

 earth, a production of temperature likewise takes 

 place *. 



168. From what source then is this increase of 

 temperature derived ? It cannot proceed from any 

 kind of action in the seed of a mechanical nature, 

 for its structure is not fitted to produce it : neither 

 can it be derived by communication from an exter- 

 nal source, for the surrounding bodies are all cold- 

 er, and are constantly drawing off the heat. Far- 

 ther, it occurs only while germination is going on ; 

 but during that process, the oxygen gas of the air is 

 constantly changing (8. 9.) into carbonic acid by uni- 

 ting with carbon (20.) furnished by the seed. In 



* Thomson's Chemistry, vol. iv. p. 238. 



