SURVEY OF SOUTH PACIFIC.

Auckland Star, Volume XXXVII, Issue 164, 11 July 1906, Page 3

SURVEY OF SOUTH PACIFIC.

(Speuial to the "Auckland Star.") CHRISTCHURCH, this day. Mr. Heimbrod, a surveyor, whose work has been among the Pacific Islands, was chosen by the New Zealand Institute's department of terrestrial magnetism to carry out the survey of the South Pacific, and he is at present in Christchurch for the purpose of comparing and correcting his instruments with those in the Christchurch Magnetic Observatory. He explained that his observations will embrace several more branches of magnetic inquiry, than merely getting the declinations, but these arc the particulars ot the most practical importance. It is now a comparatively long time since any observations wen- made in the Pacific, and consequently a lot? of the figures now available are out of date. For instance, at Suva the declination .(the angle between the true and magnetic north) is charted as 9deg. 40min., where as it is now between lOdeg. 20 mm. and lOdeg. .OOmin. over the whole Pacific area. The declinations have altered very much since the last magnetic survey, and the ■•harts still show the old figures, though in many cases these, have been observed to be Avrong. Up till the present there has not been very much done in magnetically surveying the &reat oceanic areas, and the knowledge now possessed of the distribution of the earth's magnetism is practically confined to what has been found from observations ashore. The conditions available for this work ashore are generally somewhat disturbed, and this a.ffects the results to some extent. Only a few isolated observations have been made ho far in the great ocean areas by such expeditions as tho?e of the Challenger and Hie Gazelle and British survey ships. The Carnegie Institute, to undertake the international scheme in which the various . maritime nations had co-operated, chartered a sailing vessel, the Galilee, Which is at present cruising in the Xorth Pacific. Observations arc to be made on board this vessel every day. Mr. Heimbrod's special work is to reoccupy the stations where observations have been previously made in the Pacific Islands, so as to assess the alterations that have taken place in the forces of the terrestrial magnet during the subsequent period. Some of these prior observations date back as far as 1855. and some still earlier. As far as is known the rate of variation in the magnetic declination is roughly one minute of arc per annum. Mr. Heimbrod has completed his work in the Fiji section, and will go hence to Auckland after completing the process of testing his instruments at Christchurch. This will probably take at least a week. From Auckland Mr. Heimbrod will go to Tahiti and the Marquesas some time next month, making observations at Raratonga on the way. He will then return, via Auckland, to the Australian stations and tho New Hebrides. Nest, he will again come to Auckland, and then will go to Tonga. Samoa will be the last scene of his operations, .and is also his base station. The objects of ! the work are, he says, mainly scientific, but part of the data collected will be of great value to navigators, enabling the making of new and corrected charts. - The rate of change in the declination in this-area is not well known, and .the . set of observations being made will" be very; valuable in fixing that rafe» . . j t