| | [No title] (Site not responding. Last check: ) |
 | | The liquid at one end is brought to the level at that point, and the vertical distance of the point at the other end of the tube is the difference between the level of the liquid (the same level as the first point) and the end of the tube. |
 | | Determining differences of elevation by indirect means, e.g., (a) vertical angles and horizontal distances (trigonometric leveling), (b) deriving altitudes from values of atmospheric pressure measured with a barometer (barometric altimetry), or (c) deriving altitudes from values of the boiling point of water determined with a hypsometer (thermometric altimetry). |
 | | A leveling instrument in which the line of sight is kept horizontal (to within several minutes of the vertical), regardless of the orientation of the vertical axis of the instrument by having the line of sight reflect from the free surface of a pool of mercury within the instrument. |
| www.ngs.noaa.gov /PUBS_LIB/GEOID/Droman_papers/glossary/xml/L.xml (7312 words) |