Chap. VI.] Mathematics, 77 



consideration, to fix on a universal and uniform 

 Standard of Measure, Such a standard has been 

 considered a grand desideratum, ever since men 

 began to speculate on subjects of this nature ; hut 

 probabl}^ in no former period was it ever an object 

 of so much attention, and of such diligent research, 

 as in that* which we are now reviewing. And 

 thougli none of the attempts to obtain a standard. 

 of this kind have been attended with complete suc- 

 cess, yet several of them were so ingenious, and 

 engaged so much of the inquiry of scientific men, 

 that they ought not to be passed in silence. 



Huygens, the celebrated Dutch astronomer, 

 about the middle of the seventeenth century, 

 seems to have first proposed the length of a Pen- 

 dulinn vibrating in a given time, as a standard of 

 measure. He proposed to take a pendulum that 

 should vibrate seconds, to measure it from the 

 point of suspension to the point of oscillation, and 

 to assume the third part of such a pendulum, 

 under the denomination of a horary foot, as a 

 standard to which the measure of all other feet 

 might be referred. In 1779, Mr. Hatton, of Great 

 Britain, undertook to improve on the principle of 

 Huygens, by applying a moveable point of sus- 

 pension to one pendulum, so as to produce the 

 same effect that would result from the use of two 

 pendulums, the difference of the lengths of which 

 was the intended measure*. Mr. Whitehurst con- 



* The inaccuracy to which a standard of measure derived from 

 the common pendulum is hable, arises from the difficulty o^ 



