United States Naval Institute Proceedings Volume 22, No. 2
This historic book may have numerous typos and missing text. Purchasers can usually download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1896 edition. Excerpt: ...The arm J is long enough to make intersection with the arm I. If then the arm J is trained directly on the object, inasmuch as the line H' J' joining the pivots of the arms I, J on the chart D corresponds to the base line F' J', extending between the distant stations, and as the angle C' H' J' equals the angle C F' J', it follows that the intersection of the arms I and J at C' indicates the position of the object C upon the chart D. The chart being drawn to scale, it is easy to recognize at a glance both the direction and the distance of the object C. The latest form of this position finder is that installed at Fort Hamilton, and represented in Figs. 41, 42 and 43. The larger of the instruments is fitted with a plotting table as well as a telescope. The resistance wire for each instrument is wrapped in a spiral around an insulating cylinder instead of being laid in the form of an arc, and differs from the new form of range finder principally in the addition of the plotting table. The operation of using it is much the same as the operation of using the earlier form of position finder just described. The observers point their telescopes so that the cross wires rest on the mast or funnel of the enemy's ship above the smoke. The reader at the plotting table, usually an officer, keeps moving the electrical contact of his instrument so as to keep the galvanometer needle always at zero, thus maintaining the corresponding pointer always in parallelism with the telescope at the distant station. The reader and the observers have telephone receivers on their heads and long distance transmitters on the telescopes, so that they are in constant communication. As soon as each observation is...
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- 13 Sep 2013
- United States
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