Untitled

Cromwell Argus, Volume XLI, Issue 2211, 5 September 1910, Page 2

FINDING A SHIP'S POSITION. Very few people ihave any idea of the process by means of which the modern navigator is enabled to accurately place the ship's position at a stated time on tb chart. The operation of finding the lati tude and longitude of observation can In performed in a num!x?r of ways, of whici the simplest and most convenient is by measuring the altitude of the sun above the horizon at noon, as indicated on thi vernier of t'he sextant. An arithmetical computation by the aid of logarithms is thus quickly made, which shows exactly Cow far tlie ship is north or souiih of the equator, or, in other words, the latitude. Finding tlhe lonaiUide, however, it i somewhat longer process. An observation is made eitllier in the forenoon or ! afternoon, the chronometer time of tihe horizon contact of the sun's image being noted. A calculation is then made which tdves the exact time at the spot where the ship happens to be, and, a-; the chronometer carried aboard .'hows tjhe exaci time at Greenwich, tihe prime meridian cf longitude the difference between tihe two expresses rn hours and minutes—easily convertible into degrees and miles—the distance cast or west of Greenwich. Having thus, roughly speaking, found the latitude ind longitude, a dot m placed on the chart at the exact ixrmt whore the lines of latitude and longitude cross denotes thf ship's exact situation.