SECT, xii.] WEIGHTS AND MEASURES. 101 



measure, which, is the ten-millionth part of that quadrant of 

 the meridian (N. 151) passing through Formentera and 

 Greenwich, the middle of which is nearly in the forty-fifth 

 degree of latitude. Should the national standards of the 

 two countries be lost in the vicissitude of human affairs, 

 both may be recovered, since they are derived from natural 

 standards presumed to be invariable. The length of the 

 pendulum would be found again with more facility than 

 the metre. But, as no measure is mathematically exact, an 

 error in the original standard may at length become sen- 

 sible in measuring a great extent, whereas the error that 

 must necessarily arise in measuring the quadrant of the 

 meridian is rendered totally insensible by subdivision in 

 taking its ten-millionth part. The French have adopted 

 the decimal division, not only in time but also in their de- 

 grees, weights, and measures, on account of the very great 

 facility it affords in computation. It has not been adopted 

 by any other people, though nothing is more desirable than 

 that all nations should concur in using the same standards, 

 not only on account of convenience, but as affording a more 

 definite idea of quantity. It is singular that the decimal 

 division of the day, of degrees, weights, and measures, was 

 employed in China 4000 years ago ; and that at the time 

 Ibn Junis made his observations at Cairo, about the year 

 1000 of the Christian era, the Arabs were in the habit of 

 employing the vibrations of the pendulum in their astrono- 

 mical observations as a measure of time. 



