PREFACE.

IX

titities of powder, See, &c: giving a complete detail of allthe circumstances attending these very numerous and ac-curate experiments, with many useful philosophical and prac-tical inferences deduced from them; the whole forming asit were a new era in the progress of this curious and importantbranch of knowledge.

VOLUME III.

Tract xxxv, on a new Gunpowder Eprouvette; show-ing its construction and use, by means of which the strengthand quality of gunpowder may be proved and evinced,in a way far more exact and easy than by any othermachine.

Tract xxxvi, on the Resistance of the Air to bodies inmotion, as determined by the Whirling Machine : showingthe exact quantity of the air’s resistance to all forms ofbodies, moved through it with slow and moderate motions;the effects of which, combined with those of the very highmotions of cannon and musket shot, furnish us with a com-plete and uniform series of resistances to all degrees of ve-locity, from the very slowest perceptible motions, to those ofthe highest and most violent.

Tract xxxvii, on the Theory and Practice of Gunnery,as dependent on the Resistance of the Air. This tract isemployed in stating the deductions abstracted from all thepreceding experiments, and applying them in many pro-blems, to the important purposes of Artillery and projectiles.Here are given complete tables of the quantity of resistanceto balls moving with every degree of velocity; with correctrules for ascertaining those that are proper to all othersizes of balls. Here are also given general rules and alge-braic formulee, for expressing the resistance to any size ofball in terms of the velocity ; with a great variety of pro-blems for determining the motions of balls in all directions,upwards, downwards, or obliquely, touching their velocitiesand times in motion, with the ranges of projectiles in the air,