The solar transit This account of the solar compass, and the meridian attachment for transit instruments was written for Young & sons . by the authors of all themodern text-books on surveying commonly used in schoolsand colleges. As a consequence, the young surveyor who soon finds theuse of the solar apparatus attached to his transit indispensablein his practice, is obliged to resort to his own ingenuity to mas-ter the principles upon which the instrument is based, or dependupon the imperfect and often incorrect account to be found inthe catalogue of the instrument maker he may happen to haveo
The solar transit This account of the solar compass, and the meridian attachment for transit instruments was written for Young & sons . by the authors of all themodern text-books on surveying commonly used in schoolsand colleges. As a consequence, the young surveyor who soon finds theuse of the solar apparatus attached to his transit indispensablein his practice, is obliged to resort to his own ingenuity to mas-ter the principles upon which the instrument is based, or dependupon the imperfect and often incorrect account to be found inthe catalogue of the instrument maker he may happen to haveon hand, To attempt to adjust and use any instrument withoutthoroughly understanding its principles, can only result inunreliable work, which fact has been notably demonstrated inthe use, or rather abuse of the Solar Transit. It is the design of this paper to supply a clear and conciseaccount of the instrument and its modifications, for the use ofsurveyors, and especially of those who may not be familiar withthe astronomical problems involved in its construction, a briefexplanation of which will first be given. The Diurnal For our purpose, theearth, so infinitely small incomparison with celestialmagnitudes, may be sup-posed to be a fixed point Cin space around which re-volves the celestial sphereON HZ, Fig. i, in which Zrepresents the zenith andN the nadir of the ob-server ; PCP/ the polaraxis, about which the diur-nal motion is apparentlyperformed; O E H W thecelestial horizon whose poles are Z and N, and AEQW thecelestial equator whose poles are P and V. All circles pass-ing through Z and N are called verticals, and those throughP and P are meridians or hour circles, the one passing alsothrough Z being the meridian of the place, or simply the MERIDIAN. All the circles mentioned are great circles, that is, circleswhose planes pass through C the center of the sphere. Thecircle BSD, described by the star at S in its diurnal motion, isa less circle. The distance from P or
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Keywords: ., bookcentury1800, bookdecade1880, bookidsolartransit, bookyear1887
