The concepts and theories of modern physics / By J.B. Stallo.

  • John Stallo
Date:
1900
Catalogue details

Licence: In copyright

Credit: The concepts and theories of modern physics / By J.B. Stallo. Source: Wellcome Collection.

    122/376 (page 72)
    absolute quantity in the popular sense (in wliicli it is, in fact, a conservation of velocities), would be possible only in a world without differences of density or struct- ure. If motion were conserved in this sense, there could be neither phenomenal diversity, nor phenomenal change. To the universe as we know it, with its inces- sant transformations, the assumed principle of the con- servation of motion can have no application. This was seen, dimlj^ at least, by Leibnitz, who denied that there was any conservation of motion in the Cartesian sense. His denial found its most pointed expression in an essay entitled “ Short demonstration of the memorable error of Descartes and others in regard to a law of nat- ure, according to which, as they claim, God always con- serves the same quantity of motion, which they also abuse in mechanics.” * To the Cartesian doctrine of the conservation of the quantity of motion he opposed the principle of the conservation of vis viva—of the product of mass into the square of its velocity. Here was the origin of the famous controversy be- tween the Leibnitians and Cartesians, respecting the true measure of the forces in the universe, which was par- ticipated in by so many mathematicians and philoso- phers, and to which, as is well known, a late and inap- posite contribution was made by Kant. This contro- versy has long since been finally settled; but it is so important for my ulterior puiiwse to clear up tlie prevalent misconceptions of the true import of the principle of the conservation of energy, that I devote a moment’s consideration to its merits. * “ Brevis dcmonstratio erroris memorahilis Cartesii et alioi'wn ci)'ca legem naturae, seeundum guam vohmt a Deo eandem sonper quantitatem nioUh eonservari, qud et in re mechanied ahutwdur. Acta Eiud., Lips., 16S6 (Leibu., opp. math., vol. vi, p. 117).