422 THE YARD, PENDULUM, AND METRE. 



theoretical perfection (which, I shall show, may be 

 done). We may, too, retaining, all the convenience of 

 our existing denominations (so far as they are convenient) 

 superadd to them, by permissive legislation, the addi- 

 tional convenience of a decimal system for facility of 

 calculation : relying on its holding its ground if really 

 affording such facility, or working its way into general 

 use, and ultimately driving out the old system, if found 

 by the mass of the population to be practicably pre- 

 ferable. This last is the course I would myself prefer, 

 and I think it best to say so in the outset, lest those 

 who may take a contrary view should imagine a foregone 

 conclusion to be urged upon them under the semblance 

 of free inquiry. 



(3.) It is unnecessary, of course, to observe that, the 

 measurement of length being required for almost every 

 purpose of construction as well as for every intelligible 

 statement of the sizes of material objects, the lengths 

 of journeys, the distances of places, &c. renders indis- 

 pensable the recognition, in every community, of some 

 common standard, some well-known and identifiable 

 unit t by whose repetition great, and by whose aliquot 

 subdivision small lengths, distances, sizes, &c., may be 

 expressed in words and numbers. The common sense 

 of mankind, moreover, would naturally point, in the 

 selection of such unit, to some object of common oc- 

 currence, of moderate linear dimension, and of which 

 individual exemplars differed but little, or, if possible, 

 not at all in this respect ; so that appeal might at 

 once be made to such exemplar in case of a question 



