Page:Philosophical Transactions - Volume 096.djvu/25

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II. The Bakerian Lecture on the Force of Percussion.By William Hyde Wollaston, M.D. Sec. R. S.

 

Read November 14, 1805.

When different bodies move with the same velocity, it is universally agreed that the forces, which they can exert against any obstacle opposed to them, are in proportion to the quantities of matter contained in the bodies respectively. But, when equal bodies move with unequal velocities, the estimation of their forces has been a subject of dispute between different classes of philosophers. Leibnitz and his followers have maintained that the forces of bodies, are as the masses multiplied into the squares of their velocities, (a multiple to which I shall for conciseness give the name of impetus); while those, who are considered as Newtonians, conceive that the forces are in the simple ratio of the velocities, and consequently as the momentum or quantitas motus, a name given by Newton to the multiple of the velocity of a body simply taken into its quantity of matter.

It cannot be expected that at this time any new experiment should be thought of, by which the controversy can be decided, since the most simple experiments that have already been appealed to by either party have received different interpretations from their opponents, although the facts were admitted.