LIFE of Dr HU'tTON. '>jy 



ed, nor, 1 think, the juftnefs of many of his conclufions. His 

 explanations of cohefion, heat, fluidity, deferve particular atten- 

 tion. In one thing, however, he feems to have fallen into an error, 

 which runs through much of his reafoning, concerning the 

 principles of gravitation and inertia. He affirms, that " without 

 " gravity, a body endowed with all the other material qualities 

 would have no inertia ; that it would not diminiih the velo- 

 " city of the moving body by which it fhould be aduated, nor 

 " would it move a heavy body whatever were its velocity *." 

 Now, this propofition, though from its nature it cannot be 

 brought to the immediate tefl of experience, is certainly incon- 

 fiflent with the principles of mechanics ; at the fame time, it is 

 true, that we would not, in the cafe here fuppofed, have the 

 fame means of meafuring the motion lofl, or gained by collifiore, 

 which we have in the adlual flate of bodies. This is perhaps what 

 mifled Dr Hutton ; and though his remarks on the meafures 

 of motion and force are very acute, and many of them very juft, 

 the mathematical reader will regret the want of that mode of 

 reafoning, which has raifed mechanics to fo high a rank among 

 the fciences.. 



It is impofTible not to remark the a^nity of this theory with 

 that of the celebrated Boscovich, in which, as in this, all the 

 phenomena of the material, world are explained, by the fuppofi- 

 tion of forces varioufly modified, and without the afliftance of 

 folid or extended particles. Thefe forces are fuppofed to be ar- 

 ranged round mathematical points, which are moveable, and acfl 

 on, one another by means of the forces furrounding them. A 

 mofl ingenious application of this principle is made to all the 

 ufual refearches of the mechanical philofophy, and, it mufl be 

 eonfefTed, that few theories have more beauty and fimplicity to 

 recommend them, or do better affifl the imagination in the ex- 



planatign^ 



* I)SJfertations,ij(.c. p. 312. § 31, 



