ON DRAWING, WRITING, AND MEASURING. 83 



cally possible, even if it were determined what the standard ought to be. 

 " The observation of the isochronism of the small vibrations of a pendulum, 

 and the ease and certainty with which the length of a pendulum vibrating 

 seconds may be ascertained, have suggested," says Mr. Laplace,* in his 

 account of the system of the world, " the idea of employing this length 

 as a universal measure. We cannot reflect on the prodigious number of 

 measures in use, not only among different nations, but even in the same 

 country, their capricious and inconvenient divisions, the difficulty of deter- 

 mining and comparing them, the embarrassment and the frauds which they 

 occasion in commerce, without regarding, as one of the greatest benefits 

 that the improvements of the sciences, and the ordinances of civil govern- 

 ments can render to humanity, the adoption of a system of measures of 

 which the divisions being uniform, may be easily employed in calculations, 

 and which may be derived, in a manner the least arbitrary, from a funda- 

 mental magnitude indicated by nature itself. A nation that would intro- 

 duce such a system of measures, would unite to the advantage of reaping 

 the first fruits of the improvement, the pleasure of seeing its example 

 followed by other countries, of which it would thus become the benefactor : 

 for the slow but irresistible empire of reason must at length prevail over 

 national jealousies, and over all other obstacles that are opposed to a mea- 

 sure of which the convenience is universally felt. Such were the motives 

 that determined the constituent assembly to intrust the Academy of Sciences 

 with this important charge. The new system of weights and measures is 

 the result of the labours of the Committee, seconded by the zeal and infor- 

 mation of several members of the national representation.'!* 



" The identity of the calculation of decimal fractions and of whole 

 numbers, leaves no doubt with respect to the advantage of the division of 

 measures of all kinds into decimal parts : it is sufficient, in order to be 

 convinced of this, to compare the difficulty of compound multiplication and 

 division, with the facility of the same operations where whole numbers only 

 are concerned, a facility that becomes still greater by means of logarithms, 

 of which the use may also be rendered extremely popular by simple and 

 cheap instruments. The decimal division was therefore adopted without 

 hesitation ; and in order to preserve the uniformity of the whole system, it 

 was resolved to deduce every thing from the same linear measure and its 

 decimal divisions. The question was then reduced to the choice of this 

 universal measure, to which the name of metre was to be given. 



" The length of the pendulum, and that of a meridian of the earth, are 

 the two principal standards that nature affords us for fixing the unit of 

 linear measures. Both of these being independent of moral revolutions, 

 they cannot experience a sensible alteration without very great changes in 

 the physical constitution of the earth. The first method, which is of easy 

 execution, has the inconvenience of making the measuf e of length depend 

 on two elements, heterogeneous with respect to itself and to each other, 

 gravitation, and time ; besides that the division of time into small portions 



* Systeme du Monde, liv. i. c. 12. 



f Report on the choice of a unit of measure, by Borda, Lagrange, Laplace, 

 Monge, and Condorcet, Mem. de 1'Acad. Paris, 1788. H. 7-17. 



G2 



