Volume 1
A course of lectures on natural philosophy and the mechanical arts / by Thomas Young.
- Thomas Young
- Date:
- 1845
Licence: Public Domain Mark
Credit: A course of lectures on natural philosophy and the mechanical arts / by Thomas Young. Source: Wellcome Collection.
Provider: This material has been provided by King’s College London. The original may be consulted at King’s College London.
117/670 page 83
![cally possible, even if it were determined what the standard ought to he. “ The observation of the isoclironism 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 ]\Ir. Laplace,* in his account of the system of the world, “ tire idea of employing this lengtli 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 countr}’, 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 unifonn, 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 wei’e 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.t “ 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 Avhere whole numbers only are concerned, a facility that becomes still greater by means of logarithms, of Avhich the use may also be rendered extremely popular by simple and cheap instruments. The decimal division Avas therefore adopted Avithout 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 Avas then reduced to the choice of tlris universal measure, to Avhich the name of metre Avas to be giA'en. “ The length of the pendulum, and that of a meridian of the earth, arc 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 Avithout very great changes in the physical constitution of the earth. Tlie first method, Avhich is of easy execution, has the inconvenience of making the measure of length depend on tAvo elements, heterogeneous with respect to itself and to each other, gravitation, and time ; besides that the division of time into small portions * Systemc du Monde, liv. i. c. 12. t Report on the choice of n unit of measure, hy Borda, Lng-ranjre, T.aplncc, Monge, and Condorcet, Mdm. de I’Acad. Paris, 1788. 11. 7-17.](https://iiif.wellcomecollection.org/image/b21301840_0001_0117.jp2/full/800%2C/0/default.jpg)
