File:Transactions (1871) (14596942987).jpg

Identifier: transactionsmining31amer (find matches)
Title: Transactions
Year: 1871 (1870s)
Authors: American Institute of Mining, Metallurgical, and Petroleum Engineers
Subjects: Mineral industries
Publisher: New York (etc.)
Contributing Library: Gerstein - University of Toronto
Digitizing Sponsor: University of Toronto

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Text Appearing Before Image:
Hoskolds Mining and Civil Engineers Transit-Theodolite.Diagram, View from Above. upper plate shown has three small projections upwards, 1, lr, lr/,to which the fingers are applied with pressure for clamping thewhole together, including, of course, the theodolite. Fig. 11 is a sectional elevation of Fig. 10, showing the formof the fixing- or clamping-plate 1 V more clearly. At the bot-tom of the triangular leveling-plate, three conical pointed shortprojections are shown. They are steel points screwed into thetriangular plate at the angles of an equilateral triangle, and maybe used with the theodolite upon a stone pillar, or wall, or insome low position, without using the tripod-stand. Fig. 12 represents the trough magnetic compass, the needle W I MPROVBD I«;;m OF TRANSH I ill: .11 B. of which has 11t\ Bmall points; and by the use of a band-Lthe coincidence of the needle-points with the Bero of th<in:i\ l rved with greater exactitude. It will be seen in I 3, 1<i ami 11.
Text Appearing After Image:
Plan of Locking-Frame.Cross Section of Locking-Frame. Figs. 2, 4 and 8 that the long-trough magnetic compass iemounted on the top of the telescope; but there is a groove,specially made, under the horizontal divided circle, so that anobserver may place the magnetic compass in either of these 902 AN (MPROVED FORM OF TR ANSIT-T1I KODOLITE. Fig. 12. a positions, to suit convenience or clearness of vision. Thediameter of the horizontal circle is 6 in., divided upon silverto 15 niin., witli verniers subdivided to read to 1> see. of arc;and, by means of the micrometrical eye-piece attached to the telescope, angles may be measured to 1 second of arc, and byestimation to less. Traversing-Stand. When iisiiiL? the new instrument to connect the first line inan underground survey to the surface by direct telescopic sightdown a vertical shaft, a specially constructed tripod-stand, in-vented by the writer, is employed. Its legs atthe upper part are mounted with a traversing-apparatus, i.e., a tab

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