432 THE YARD, PENDULUM, AND METRE. 



and named the others in a certain order as its successors 

 in the event of its destruction or loss, omitted the clause 

 identifying its length with any numerical multiple of the 

 pendulum. In fact, then, our yard is a purely individual 

 material object, multiplied and perpetuated by careful 

 copying ; and from which all reference to a natural origin 

 is studiously excluded, as much as if it had dropped 

 from the clouds. Apart, then, from the extraordinary 

 pains taken in its construction, and from the singularly 

 fortunate but at the same time purely accidental coinci- 

 dence which I shall presently mention, it has no preten- 

 sions whatever to be regarded as a scientific unit. 



(13.) Let us now consider the claim which the pen- 

 dulum, in the abstract, as a measure of the earth's gravi- 

 tation, can advance for its reception as a fundamental 

 and universal standard of length (and here, incidentally 

 it may be remarked that, as a length, it is not more in- 

 convenient than the metre, being within about a quarter ot 

 an inch the same).* One of the reasons assigned by the 

 French Savans for their rejection of it in favour of the 

 metre, and, as would appear, the only one which 

 weighed with them (for their other reason ostensibly 

 advanced is a mere appeal to the political passions of the 

 time) was the dependence of the length of the pendulum 



* The metre has this inconvenience, as compared with the yard 

 that while the latter can he readily extemporized by a man of 

 ordinary stature (and often is so in practice) by holding the end of a 

 String or ribband between the finger and thumb of one hand at the 

 full length of the arm extended horizontally sideways, and marking 

 the point which can be brought to touch the centre of the lips 

 (facing full in front) ; the former is considerably too long to afford 

 the same facility. 



