The Mechanic; Containing Two Hundred and Fifteen Articles, Selected and Original. Arranged Under the Following Heads

The Mechanic; Containing Two Hundred and Fifteen Articles, Selected and Original. Arranged Under the Following Heads : I. Manufacture and Trade, II. Philosophical Apparatus and the Fine Arts, III. Rural and Domestic Economy, and Volume 2

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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. 1825 edition. Excerpt: ...which carries the whole apparatus of the eye-glass, &c. and then to draw the eyeglass out by means of its sliding work, till the threads of the micrometer are in its focus, which is known by their appearing most distinct, &, c.;" then thrust the short tube before-mentioned' into its proper place, as far as the shoulders of the brasswork will admit, and place the object-glass in its cell, and looking through the telescope at some very distinct object, slide the wooden tube in or out, till you make the object appear most distinct, or till it has the least motion upon the threads when the eye is moved to and fro; for then the threads of the micrometer will be in the common focus of both glasses, and that will be the proper distance that the object-glass ought always to be at from the threads; and there should be made some mark or ketch in the wooden tube, in order to set it always at the same distance. The proper distance of the threads from the object-glass being thus settled, the table for turning the revolutions, 8:0. 42. von. 11. 2 K ' of the screw into angles, or minutes and seconds of a degree, may be made several ways; but as good and easy a method as any is, carefully to measure how many inches and parts of an inch the object-glass is distant from the threads, and with the same scale to find also how many inches and parts of an inch, a hundred, 8L0. revolutions and threads of the screw of the micrometer are equal to: then making the first distance radius, the last will be the sine or tangent of an angle answer-" ing to 100 revolutions. And having the angle answering to 100 revolutions, the angle for any other number will be easily known and set down in the table, as also the parts of a revolution; for in small...show more

Product details

  • Paperback | 198 pages
  • 189 x 246 x 11mm | 363g
  • Rarebooksclub.com
  • United States
  • English
  • black & white illustrations
  • 1236845714
  • 9781236845719