340 Of the Propagation of Heat 



honour of being the first to stumble on those treasures 

 which everywhere lie so slightly covered. 



In respect to the "concluding reflection " of the First 

 Edition of this Essay, — though some may smile in 

 pity, and others frown at it, I am neither ashamed nor 

 afraid to own, that I consider the subject as being of the 

 utmost importance to the peace, order, and happiness of 

 mankind, in our present advanced state of society. But to 

 return from these digressions — 



Though it appeared to me that the important fact I 

 undertook to investigate, relative to the manner in which 

 heat is propagated in Fluids, is fully established by the 

 experiments, of which an account has been given in the 

 preceding Chapters of this Essay ; yet, as a thorough 

 examination of the subject is a matter of much impor- 

 tance in many respects, I did not rest my inquiries here, 

 but made a number of experiments with a view to 

 throwing still more light upon it, and enabling us to 

 form more clear and distinct ideas respecting those curi- 

 ous mechanical operations which appear to take place in 

 Fluids, when Heat is propagated in them. 



Having frequently observed when a quantity of water 

 in one of my glass jars was frozen to a cake of ice, by 

 placing the jar in a freezing mixture, that, as the ice first 

 began to be formed at the sides of the jar, and increased 

 gradually in thickness, the portion of water in the axis 

 of the jar (which last retained its fluidity), being com- 

 pressed by the expansion of the ice, was always forced 

 upwards towards the end of the process, and formed a 

 pointed projection of ice in the form of a nipple {pa- 

 pilla\ which was sometimes above half an inch high in 

 the middle of the upper side of the cake, — I was led by 

 that circumstance to make the following interesting ex- 

 periments. 



