Gunnery for Non-Commissioned Officers (Paperback)

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. 1893 Excerpt: ...for 600 read 60, for 700 read 70, and so on. Having determined the base AC in the manner described, the operator sets the instrument for that base; passes to A and takes position facing O, the picket A between his toes; presses the button which operates the horizon-glass to the side marked "Range,1' and looks through the eyeholes in the end of the instrument. The object O will be seen directly, and the picket C by reflection, the latter in the direction D. He then turns the range-cylinder with the right hand, causing the image of C to travel from D to O. The distance AO will be indicated on the range-cylinder. It will be seen that from 600 to 950 on the scale of ranges the numbers are in full; beyond that range, in hundreds. Thus, 10 means ten hundred (1000); 11, eleven hundred (1100); and soon. The assistant seeing the operation completed returns and gathers up the pickets. The Weldon Rangefinder is perhaps the simplest of all the instruments yet devised for determining ranges. It is essentially a pocket-instrument, has no adjustments, and is scarcely in. Vm- Dt-A/i I susceptible of injury. If it be correct when new it will continue so. Every new instrument, therefore, should be carefully tested before being put in practical use. The Weldon range-finder consists of a small glass prism, the largest angle of which is 88 34' 3," and the smallest just half this amount. The third angle must of course be 180 minus the sum of these two. The prism is protected by a metal frame which wholly covers its upper and lower sides and the face opposite the largest angle. The face opposite the smallest angle is wholly exposed, the remaining face partially so. The wholly covered face is silvered over so as to act as a mirror. A small handle is attached to...