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TRACT XXXVII.

THEORY AND PRACTICE OF GUNNERY, AS DEPENDENT ON THERESISTANCE OF THE AIR.

Sect. 1 . In this tract it is proposed to deduce the gene-ral conclusions, from the long series of experiments made inTracts 34 and 36, and to make applications of them to va-rious practical uses, particular^ to the theory and practiceof gunnery, as dependent on, or modified by the resistanceof the air, now that its effects have, for the first time, beenin part satisfactorily ascertained, by very numerous and ac-curate experiments.

2. In some parts of my Course of Mathematics, certainnotices are to be found concerning the subject, both as con-nected with the air’s resistance, and as independent of it.Thus, in the 2nd volume of that course, in props. 19, 20,21, 22, is delivered all that relates to the parabolic theoryof projectiles, that is, the principles and conclusions Avhichwould obtain, and regulate such projects, if they were notimpeded and disturbed in their motions, by the air in whichthey move. For, from the enormous resistance of that me.dimn it happens, that many military projectiles, especiallythe smaller balls discharged with high velocities, do not rangeso far as a 20th part of what they would naturally do inempty space. That theory then can only be useful in somefew cases of slow motions, not exceeding the velocities of200, or 300, or 400 feet in a second of time, when the pathof the projectile differs but little from the curve of a parabola.Also, at pa. 160, 8tc, are given several other practical rulesand calculations, depending partly on the foregoing parabolictheory, and partly on the results of certain experiments per-formed with cannon balls.

VOL. III.

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