Report on the scientific results of the voyage of during the years 1873-76 : under the command of Captain George SNares, , Captain Frank Turle Thomson, . ? ih, Vctyng H MS Qiallengi ? ? I ?? nl i ,\!,i|, _ ISOBA 01 I HI KORTH ITHE. A.»; Dftlt- THE VOYAGE OF CHALLENGER. PHYSICS AND CHEMISTRY. REPORT on the Magnetical Results obtained by Challengerduring the years 1873-1876. By Staff-Commander E. W. Creak,, Since the year 1700, when Halley published his map of equal curves of magneticdeclination for the Atlantic and Indian Oceans
Report on the scientific results of the voyage of during the years 1873-76 : under the command of Captain George SNares, , Captain Frank Turle Thomson, . ? ih, Vctyng H MS Qiallengi ? ? I ?? nl i ,\!,i|, _ ISOBA 01 I HI KORTH ITHE. A.»; Dftlt- THE VOYAGE OF CHALLENGER. PHYSICS AND CHEMISTRY. REPORT on the Magnetical Results obtained by Challengerduring the years 1873-1876. By Staff-Commander E. W. Creak,, Since the year 1700, when Halley published his map of equal curves of magneticdeclination for the Atlantic and Indian Oceans, that method of representing the valuesof the magnetic elements for frequent reference seems to have found general favour,probably from the facility with which the information they contain can be since Halleys day the following authors have published maps of the declination :—Mountaine andDodson in 1756, Churchman in 1794, Yeatesin 1817, and Barlow in 1833. Again, in 1819, Hansteen1 added maps of the inclination to those of the declinationfor different epochs between the years 1600 and 1787, and although the angular directionof the freely suspended needle was thus known for a considerable portion of the earthssurface, it was not until the
Size: 1845px × 1354px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, bookdecade1880, booksubjectscientificexpedition
