Author : C. L. Berger & Sons
Release : 2013-09
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Kind : eBook
Book Rating : 618/5 ( reviews)

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Book Synopsis Engineering Surveying and Mining Instruments by : C. L. Berger & Sons

Download or read book Engineering Surveying and Mining Instruments written by C. L. Berger & Sons. This book was released on 2013-09. Available in PDF, EPUB and Kindle. Book excerpt: 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. 1916 edition. Excerpt: ...then, if a meridian mark is used (which is not absolutely necessary), the transit should be set up in the meridian by the main telescope and the pointing on the sun or star may be made with the auxiliary telescope with or without the prism, as conditions may require. In observing transits the auxiliary telescope should be mounted on top and ranged into line with the vertical wire of the main telescope by using the two opposing screws as explained. In making solar and stellar observations with the main telescope and prism attachment, the telescope should always be reversed through the standards with the objective down instead of up. Cross Section Showing Our Edge-bar Needle and Compass-Likewise the watertight needle lifter combined with the toothed variation ring and pinion motion for instantaneously changing the graduation to any declination East or West. The needle shown in the cross section of our Transit compass also in the top view on opposite page, represents the form adopted and preferred by us for all of our compass instruments, because it has its greatest dimensions in the vertical direction; hence its name. At the ends, where it is read, it is quite thin, but increases in thickness symmetrically towards the central part to give it the rigidity necessary to retain the true longitudinal shape and yet be very light of weight to minimize the dulling of the pivot on which it swings. The point of suspension in the steel cap and the two ends of the needle are in a straight line, thereby forming the geometric axis. The advantage derived from the edge-bar form, therefore, is that its magnetic axis must be contained in the geometric axis of the needle, whence it follows that there is no index error at its reading ends. This cannot be...