. Annual report of the Chief of Ordnance to the Secretary of War ... levels, 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 the 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 wdl be sufficient to mark every ten minutes. These ten-minute spaces can be divided in th
. Annual report of the Chief of Ordnance to the Secretary of War ... levels, 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 the 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 wdl 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—Euc. 136). ffl J*£a:£e .T.
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Keywords: ., bookcentury1800, bookdecade1880, bookpublisherwashi, bookyear1884
