144 Ejects of Heat modified ly Compression. 



we balance the fertility of a principle, in explaining the 

 phenomena of nature, ^tgainst its improbability as an hypo- 

 thesis : the partial view which we then obtain of truth is 

 perhaps the most attractive of anv, and most powerfully 

 stimulates the exertions of an active mind. The mist which 

 obscured some objects dissipates bv degrees^ and allows 

 them to appear in their true colours ; at the same time, a 

 distant prospect opens to our view, of scenes unsuspected 

 before. 



Entcrine: now seriously into the train of rcasoninrr fol- 

 lowed by Dr. Hulton, I conceived that the chemical effects 

 ascribed by him to compression, ought, in tlie first place, to 

 be investigated ; for unless some good reason were given us 

 for believing that heat would be modified by pressure, in the 

 manner alleged, it would avail us little to know that they 

 had acted together. He rested his belief of this influence on 

 analogy, and on the satisfactory solution of all the pheno- 

 mena furnished by this supposition. It occurred to me, 

 however, that this principle was susceptible of being esta- 

 blished in a direct nianner by experiment, and I urged him 

 to make the attempt ; but he always rejected this proposal^ 

 on account of the immensity of the natural agents, whose 

 operations he supposed to lie far beyond the reach of our 

 imitation; and he seemed to imagine that any such attempt 

 must undoubtedly fail, and thus throw discredit on opinions 

 already sufficiently established, as he conceived, on other 

 principles. I was far, however, from being convinced by 

 these arguments ; for, without being able to prove that any 

 artificial compression to which we couM expose the car- 

 bonate would effectually prevent its calcination in our fires, 

 I maintained, that we bad as little proof of the contrary, 

 and that the application of a moderate force might passibly 

 perform all that was hypothetically assumed in the Huttoniaii 

 theory. On the other hand, I considered myself as bound 

 m practice to pay deference to his opinion, in a field which 

 he had already so nobly occupied, and abstained, during 

 the remainder of his life, from the prosecution of some ex- 

 periments with compression which I had begun ia 1790. 



Ill 170s I resumed the subicct with eagerness, bcinu' still 



of 



