MODIFIED by COMPRESSION. 75 



fcurity of his writings. I was induced by that charm, and by 

 the numerous original facts which his fyftem had led him to 

 obferve, to liften to his arguments, in favour of opinions which 

 I then looked upon as vifionary. I thus derived from his con- 

 verfation, the fame advantage which the world has lately done 

 from the publication of Mr Playf air's Illujl rations j and, ex- 

 perienced the fame influence which is now exerted by that 

 work, on the minds of our moft eminent men of fcience. 



After three years of almoft daily warfare with Dr Hut- 

 ton, on the fubject of his theory, I began to view his funda- 

 mental principles with lefs and lefs repugnance. There is a 

 period, I believe, in all fcientific inveftigations, when the con- 

 jectures of genius ceafe to appear extravagant -, and when 

 we balance the fertility of a principle, in explaining the phe- 

 nomena of nature, againft its improbability as an hypothefis : 

 The partial view which we then obtain of truth, is perhaps the 

 moft attractive of any, and moft powerfully ftimulates the 

 exertions of an active mind. The mill which obfcured fome 

 objects diffipates by degreee, and allows them to appear in their 

 true colours ; at the fame time, a diftant profpect opens to our 

 view, of fcenes unfufpected before. 



Entering now ferioufly into the train of reafoning fol- 

 lowed by Dr Hutton, I conceived that the chemical effects 

 afcribed by him to compreflion, ought, in the firft place, to be 

 inveftigated ; for, unlefs fome good reafon were given us for 

 believing that heat would be modified by prefliire, in the man- 

 ner alleged, it would avail us little to know that they had 

 acted together. He refted his belief of this influence on ana- 

 logy j and on the fatisfactory folution of all the phenomena, 

 furnifhed by this fuppofition. It occurred to me, however, 

 that this principle was fufceptible of being eftablifhed in a di- 

 rect manner by experiment, and I urged him to make the at- 

 tempt 5 but he always rejected this propofal, on account of 



K 2 the 



