Leveling: Barometric, Trigonometric and SpiritD. Van Nostrand, 1887 - 145 стор. |
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Загальні терміни та фрази
accuracy accurate adjustment air column aneroid angle approximate aqueous vapor atmosphere atmospheric refraction backsight barome barometric formula base station boiling bubble cistern cloth coefficient of refraction computed correction deduced density determined difference of altitude difference of elevation difference of level diurnal eleva eliminate ence equation equilibrium eral Errors due feet formula geodesic leveling Gilbert gradient greater Guyot's Collection heat height horizontal hygrometer hypsometric inch instru instrument ivory point justment l-log length of sight line of light lower station mean measured ment mercurial barometer meters method micrometer miles Mississippi River Commission moisture Ordnance Survey perature Plantamour's pressure scale screw servations source of error spirit level static equilibrium statical formulæ stratum strument surface tables tance target telescope temperature temperature and humidity term thermometer tical tion triangulation trigono tube ture U. S. C. S. Report U. S. Geological U. S. Lake Survey variation Williamson
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Сторінка 11 - 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.
Сторінка 11 - ... up of a glass cylinder F, which allows the surface of the mercury q to be seen, and a top plate G, through the neck of which the barometer tube / passes, and to which it is fastened by a piece of kid leather, making a strong but flexible joint.
Сторінка 19 - 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.