74 jDT' Wollaston on a Method, (^c. 



tion of cold, and the vacuum produced by this condensation 

 gives opportunity for a fresh quantity to arise from the oppo- 

 site ball, with proportional reduction of its temperature. 



According to a theory that does not admit of positive cold, 

 we should represent the heat of the warmer ball to be the 

 agent in this experiment, generating steam as long as there 

 remains any excess of heat to be conveyed. But if we would 

 express the cause of its abstraction, we must say that the cold 

 mixture is the agent, and may observe, in this instance, that 

 its power of freezing is transferred to a distance, by what may 

 be called the negative operation of steam. 



The instrument, by which this is effected, may aptly be 

 called a Cryophorus, which correctly expresses its office of 

 frost-bearer. 



