Engineers' Surveying Instruments, Their Construction, Adjustment, and UseJ. Wiley & sons, 1893 - 391 páginas |
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Engineers' Surveying Instruments, Their Construction, Adjustment, and Use Ira Osborn Baker Sin vista previa disponible - 2015 |
Términos y frases comunes
accuracy accurate adjustment alidade altitude aneroid average error azimuth back-sight barometer barometric formulas bubble chain chain-man clamp computed correction cross hairs declination determine difference of level direction distance dumpy level edge eliminated engineering equal equation eye-piece feet field fore-sight formula gradient graduation horizontal axis hour angle inch instrument intercept intersection justment latitude length of sight lens leveling rod limb line of collimation line of sight magnetic magnifying power measured mercury meridian method motion move needle object-glass objective observations optical center ordinary parallel perpendicular plane table plumb-bob polar axis position probable error refraction scale self-reading shown in Fig side slide solar apparatus solar compass solar telescope solar transit source of error spirit level stadia hairs station Survey tangent screw target tele temperature tion transit telescope tripod tube U. S. Coast vernier vertical angles vertical axis vertical circle wyes zero
Pasajes populares
Página 289 - B by means of four large screws P and the ring R ; on the ring R screws the cap S, which covers the lower parts of the cistern, and supports at the end of the adjusting screw O.
Página 292 - ... casing screwed on, and the screw at its end screwed up. The instrument can then be hung up and readjusted. The tube and its contents having been undisturbed, the instrument should read the same as before. If a little mercury has been lost during the operation, and there is none at hand to replace it, no serious harm has been done; but if much is lost, the open end of the tube may become exposed in inverting the instrument, in which case air may enter.
Página 391 - ENGINEERING AND SURVEYING INSTRUMENTS, No. 9 Province Court, Boston, Mass. They aim to secure in their Instruments: Accuracy of Division; Simplicity in Manipulation ; Lightness Combined with Strength...
Página 299 - ... altitude, whether fixed or movable, and calculate the heights. § 60. Defects. — The aneroid is a very convenient instrument and for a stationary instrument where nice readings are not required, it does very well ; but for accurate hypsometrical results it is an inferior instrument. Its defects are: 1. The elasticity of the corrugated top of the vacuum chamber is affected by repeated changes in pressure. This will produce error in the scale readings. 2. It is usually claimed that, in consequence...
Página 390 - ... etc. Complete in one volume of about 500 pages, with 125 illustrations and eight or ten folding plates. By Ira O. Baker, CE Ninth edition, 8vo, cloth $5.00 "If you wish the best book ever published in the English language on Masonry Construction, turn with confidence to this treatise.
Página 391 - TT7HBIR instruments are in general use by the US Government Engineers, Geologists and Surveyors and the range of instruments, as made by them for River, Harbor, City, Bridge, Tunnel, Railroad and Mining Engineering, as well as those made for...
Página 289 - G, i, j and k, are of box-wood ; the other parts of brass or German silver. The screw O serves to adjust the mercury to the ivory point, and also, by raising the bag, so as to completely fill the cistern and tube with mercury, to put the instrument in condition for transportation.
Página 296 - If carried on horseback, it should be strapped over the shoulders of the rider, where it is not likely to be injured, unless the animal is subject to a sudden change of gait.
Página 144 - Observatory, so that when the mean azimuth of the line was corrected for this 15" error in latitude it agreed exactly with the stellar azimuth of the line, which might have been 10" or 15" in error. On the first day all the readings were taken without a reading glass, there being four circle readings to each result. On the second day a glass was used. " On the first day the maximum error was 4 minutes, the average error was 0.8 minute, and the 'probable error of a single observation
Página 167 - C. Then set up at C, and assuming the point c on the line dC, at an estimated distance from d, and putting the table in a position parallel to that which is occupied at D, by means of...