Gurley Manual of Surveying Instruments ...W. & L. E. Gurley, 1857 - Surveying |
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Common terms and phrases
12 inch adjustment attached Beam Compasses bell metal bisect Bow Pens Boxwood brass instruments bring the bubble chain clamp and tangent clamp screw compass circle compass tripod correction cross-wires described direction divided circle edge error eye-piece FIGURE firmly furnished German Silver instruments glass graduated half degrees inch needle inches long instru Ivory Protractors Ivory Scales jacob staff legs Leveling Instrument leveling screws limb line of collimation magnetic magnifying power main plate main socket Morocco moved needle point object object-glass observation optical axis pinion placed Plain Compass plumb-bob position PRICE rack and pinion Rail Road Compass reading revolve the telescope right angles ring side sights slide socket spindle steel joints surface Surveying Surveyors tangent movement tangent screw Theodolite tripod head turned variation Vernier Compass vernier plate Vernier Transit vertical circle vertical direction visual angle watch telescope whole degrees wires wood box wyes zero
Popular passages
Page 59 - The telescope has at each end a ring of bell-metal, turned very truly and both of exactly the same diameter; by these it revolves in the wyes, or can be at pleasure clamped in any position when the clips of the wyes are brought down upon the rings, by pushing in the tapering pins.
Page 68 - ... and repeat the whole operation, until the reversion can be made without causing any change in the bubble. It would be well to test the lateral adjustment, and make such correction as may be necessary in that, before the horizontal adjustment is entirely completed.
Page 14 - ... during an entire revolution of the compass. THE SIGHTS may next be tested by observing through the slits a fine hair or thread, made exactly vertical by a plumb. Should the hair appear on one side of the slit, the sight must be adjusted by filing off its under surface on that side which seems the highest.
Page 8 - Troy to the purchaser are in all cases to be borne by him, we guaranteeing the safe arrival of our instruments to the extent of Express transportation, and holding the Express Companies responsible to us for all losses or damages on the way. TERMS OF PAYMENT are uniformly cash, and we have but one price. Our prices for instruments are nearly one-third less than those of other makers of established reputation. They are as low as we think instruments of equal quality can be made, and will not be varied...
Page 15 - In the surveyor's compass, he will observe that the position of the E and W letters on the face of the compass are reversed from their natural position, in order that the direction of the sight may be correctly read. The compass circle being graduated to half degrees, a little practice will enable the surveyor to read the bearings to quarters — estimating with his eye the space bisected by the point of the needle. The compass is usually divided into quadrants, and zero is placed at the north and...
Page 28 - Having in this manner moved back the vertical wire until, by estimation, onequarter of the space DE has been passed over, return the instrument to the point B, revolve the telescope, and if the correction has been carefully made, the wires will now bisect a point C, situated midway between D and E, and in the prolongation of the imaginary line, passing through the point B and the centre of the instrument. To ascertain if such is the case, turn the instrument half around, fix the telescope upon B,...
Page 31 - In order that the wires may trace a vertical line as the telescope is moved up or down, it is necessary that both the standards of the telescope should be of precisely the same height. To ascertain this and make the correction if needed, proceed as follows : Having the line of collimation previously adjusted, set up the instrument in a position where points of observation, such as the point and base of a lofty spire, can be selected, giving a long range in a vertical direction.
Page 69 - ... around, -so that the level bar may occupy the same position with respect to the leveling screws beneath. Should the bubble run to either end, bring it half way back by the Y nuts on either end of the bar; now move the telescope over the other set of leveling screws, bring the bubble again into the center, and proceed precisely as above described, changing to each pair of screws, successively, until the adjustment is very nearly perfected, when it may be completed over a single pair. The object...