AN I NQUIRY • 



CONCERNING THE 



SOURCE OF THE HEAT WHICH IS EXCITED BY 

 FRICTION. 



IT frequently happens that in the ordinary affairs and 

 occupations of life, opportunities present themselves 

 of contemplating some of the most curious operations 

 of Nature ; and very interesting philosophical experi- 

 ments might often be made, almost without trouble or 

 expence, by means of machinery contrived for the mere 

 mechanical purposes of the arts and manufactures. 



I have frequently had occasion to make this observa- 

 tion ; and am persuaded that a habit of keeping the eyes 

 open to everything that is going on in the ordinary 

 course of the business of life has oftener led, as it were 

 by accident, or in the playful excursions of the imagina- 

 tion, put into action by contemplating the most common 

 appearances, to useful doubts and sensible schemes for 

 investigation and improvement, than all the more intense 

 meditations of philosophers in the hours expressly set 

 apart for study. 



It was by accident that I was led to make the ex- 

 periments of which I am about to give an account; and, 

 though they are not perhaps of sufficient importance to 

 merit so formal an introduction, I cannot help flattering 

 myself that they will be thought curious in several re- 



