Identifier: annualreportofch00unit (find matches)
Title: Annual report of the Chief of Ordnance to the Secretary of War ..
Year: 1884 (1880s)
Authors: United States. Army. Ordnance Dept
Subjects: United States. Army. Ordnance Dept United States. Army
Publisher: Washington, (D.C.) : G.P.O.
Contributing Library: Allen County Public Library Genealogy Center
Digitizing Sponsor: Internet Archive

View Book Page: Book Viewer
About This Book: Catalog Entry
View All Images: All Images From Book
Click here to view book online to see this illustration in context in a browseable online version of this book.

Text Appearing Before Image:
vels, one half the error by the opposing nuts and one-half by theelevation of the gun. Repeat until the adjustment is perfect. It maybe noted that with so sensitive a level as is on this instrument if thebubble return on reversing to within one-half a division of its originalposition rlie adjustment may be considered sufficiently accurate for thework to be done. The graduation of the elevation circle or arc may now be made. Ingeneral it will be sufficient to mark every ten minutes. These ten-minute spaces can be divided in the shop when the graduations arecut. The graduation should be checked by elevating and depressingthe gun to several specified graduations. It has been found in practicethat an approximation, in setting to a specified graduation, within thelimits plus and minus, about eight seconds is as close as can be made—i. e., in a number of attempts the extreme variation noted will be aboutas stated. The instrument is reversed for graduations in depression.(10222—Bne. 136)
Text Appearing After Image:
Ord 55 2 190 APPENDIX 18. at O gives a constant position for the instrument and prevents slippingwhen using it at the higher elevations. Cylinders are also providedfor guns of 10 inches and 12 inches caliber. The axial projection isfinished to exactly the same dimensions on all the cylinders. The instrument weighs about 4 pounds, and a neat packing case, withcarrying strap, is provided for its storage and transportation. The method of using the instrument is simple, but requires that verygreat care should be exercised; not that it is particularly delicate, buton account of the sensitiveness of the level bubble, which should befree from irregular temperature effects. The bore of the gun is first thoroughly cleaned at the muzzle for alength at least as great as that of the cylinder. The cylinder is theninserted its entire length until the stop on its face bears against themuzzle. As the fit of the cylinder is very close, care should be takento have it thoroughly clean and to avoid burri

Note About Images