celerity of the bullet discharged against it. The thought was simple, ingenious, and incontestably his own. He next inquired into the resistance made by the air to projectiles of rapid motion, and which he discovered to be much greater than had been supposed by any writer on the subject; and indeed so great, that it was manifest the curve described by any shot was very different from a parabola, and consequently that all the applications of the properties of that conic section to gunnery were so erroneous as to be totally useless. For by means of this pendulum, placed at different distances from the mouth of the piece, he clearly demonstrated how much a bullet, flying with a given velocity, would gradually lose of that motion by the opposition of the air: therein furnishing to the learned a signal and instructive instance of the fallacy of the most specious theories, that do not proceed hand in hand with experiments. I should too much exceed the just bounds of a discourse of this kind, were I to enter more minutely into the system founded by Mr. ROBINS, confirmed and improved, as I find, by the labours of several of the learned in foreign parts of great celebrity[21]. I shall only add, that his performance well deserves the title he gives it of _The new principles of gunnery_, since the author may more properly be said to have invented a new science than to have added to an old one. And I believe I may venture to say, that no physico-mathematical disquisition hath done more honour to this country, or to the age, than the writings of Mr. ROBINS on this subject, which have been published, partly by this Society, partly by himself, and partly since his death (in the collection of his whole mathematical tracts) by his learned friend. But though our worthy brother will ever be celebrated for being the inventor of the true principles of gunnery, yet it would be too flattering to his memory, to say he had carried the theory of this art to perfection. He himself was far from entertaining so high an opinion of his labours; nay he expressly declared, that he left some material points to be inquired into at more leisure (which other occupations and his immature death deprived him of) and he much regretted that he wanted conveniency and opportunities for making experiments on balls of a greater weight, than what he had used for ascertaining the initial velocity of them. Much therefore are we indebted to Mr. HUTTON, who, treading in the footsteps of the deceased, hath resumed and prosecuted this last _desideratum_, and hath shewn himself not unequal to so difficult an enterprize.