35(5 DISCOURSE OX THE STUDY 



contrasted with what could be procured a few ge- 

 nerations ago, by the rude and clumsy workmanship 

 of even the early part of the last century, it will be 

 no matter of astonishment that the sciences which 

 depend on exact measurements should have made 

 a proportional progress. Nor will any degree of 

 nicety in physical determinations appear beyond our 

 reach, if we consider the inexhaustible resources 

 which science itself furnishes, in rendering the 

 quantities actually to be determined by measure 

 great multiples of the elements required for the 

 purposes of theory, so as to diminish in the same 

 proportion the influence of any errors which may be 

 committed on the final results. 



(389.) Great, indeed, as have been of late the im- 

 provements in the construction of instruments, both 

 as to what regards convenience and accuracy, it is to 

 the discovery of improved methods of observation that 

 the chief progress of those parts of science which de- 

 pend on exact determinations is owing. The balance 

 of torsion, the ingenious invention of Cavendish and 

 Coulomb, may be cited as an example of what we 

 mean. By its aid we are enabled not merely to render 

 sensible, but to subject to precise measurement and 

 subdivision, degrees of force infinitely too feeble 

 to affect the nicest balance of the usual construction, 

 even were it possible to bring them to act on it. 

 The galvanometer, too, affords another example of 

 the same kind, in an instrument whose range of 

 utility lies among electric forces which we have no 

 other means of rendering sensible, much less of 

 estimating with exactness. In determinations of 

 quantities less minute in themselves, the methods 



