New Principles of Gunnery; Containing, the Determination of the Force of Gun-Powder, and an Investigation of the Difference in the Resisting Power of
Benjamin Robins
Paperback
(RareBooksClub.com, May 14, 2012)
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. 1742 Excerpt: ...of a Screw Z going through the upper Piece. There is faften'd to the Bottom of the Pendulum a narrow Ribbon LN, which pafles between thefe Steel Edges, and which afterwards, by Means of an Opening rut in the lower Piece of Steel, hangs loofcly down, as at W. This Inftrument thus fitted, if the Weight of the Pendulum be known, and likewife the refpective Pittances of its Centre of Gravity, and of its Centre of Ofcillation, from its Axis of Sufpenfion, U will thence be known, what Motion will be communicated to this Pendulum by the Percuffton of a Body of a known Weight moving with a known Degree of Celerity, and ftriking it in a given Point; that is, if the Pendulum be fuppofed at Reft before the Percuffion, it will be known, what Vibration, it ought to make in Confequence of fuch a determined Blow-, and, on the contrary, if the Pendulum, being at Reft, is ftruck by a Body of a known Weight, and the Vibration, which the Pendulum makes after theBlow, is known, the Velocity oftheftrikingBody may from thence bedetemined. Hence then, if a Bullet of a known Weight ftrikes the Pendulum, and the Vibration, which the Pendulum makes in confequence of the Stroke, be afcertained, the Velocity, with which the Ball moved, is thence to be known. Now the Extent of the Vibration, made by the Pendulum after the Blow, may be meafured to great Accuracy by the Ribbon L N; for Jet the Preflure of the Edges U N on the Ribbon be fo regulated by by the Screw Z, that the Motion of the Ribbonbetween them may be free and eafy, tho' with fome minute Refiftance; then fettling the Pendulum at Reft, let the Part L ftf between the Pendulum and the Edges be drawn ftrait, but not trained, and fix a Pin in that Part of the Ribbon, which is then contiguous to the Edges: Let now a Ball impinge ...