Memoirs of the Literary and Phylosophical Society of Manchester (Paperback)

This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1813. Excerpt: ... ON THE MEASURE OP MOVING FORCE. BY MR. PETER EWART. (Read Nov. 18,1808.) I N the theory of mechanics, forces are understood to be mathematical quantities, capable of being measured and compared with as much certainty as lines, or surfaces, or any other mathematical quantities. Respecting the principles, however, of this measurement and comparison, various doctrines have been held. A controversy on this subject, after having been long and warmly agitated by learned men in different parts of Europe, appears, about seventy years ago, to have gradually subsided; and since that period, it has been the prevailing opinion with mathematicians, Dr. Reid says," it was dropt rather than ended, to the no small discredit of mathematics, which hath always boasted of a degree of evidence inconsistent with debutes that can oe brought to no issue." Essay on Quantity.--Philosophical Transactions, 1748. O that the argument respecting the measure of the force of a body in motion, was merely a dispute about terms, and that, though the force in question may be variously estimated, according to circumstances, it is most naturally and consistently expressed by the product arising from the mass being multiplied into its velocity. Although scientific men have, for more than half a century, been generally satisfied on this question, it must nevertheless be acknowledged that considerable difficulties have occurred in the practical application of their measure of force; and, it is remarkable, that the measure which they have rejected, appears to have been first suggested to Hooke and Huygens, by their practical observations on the motion of pendulums, and was afterwards adopted by Smeaton, as a rule for the great operations in which he had so much experience. It is much to be regre...