SUB-ANTARCTICA.

Evening Post, Volume LXXIV, Issue 138, 7 December 1907, Page 11

SUB-ANTARCTICA.

MAGNETIC OBSERVATIONS. WORK OP THE EXPEDITION. (By H. F. Skov, B'.Se.) On Tuesday morning, 12fch November, the majority of the membeis ot the expedition left ChriDtchurch by tbo early I express en route to join U\o G.S.S. Hiriomo;i. at the Bluff. The contingent included most of the biologists and all the magnetic obrerveis for the expedition, the latter comprising Dr. C. C. FaTf, of Canterbury College, Mi. H. F. Skey,« B.Sc, of the Magnetic Observatory ;. Mr. S. Tvidson, M.Sc, and Mr. H. Cook, M.Sc., both of CanterDury College staff; and Messrs 0. A. Opie and Collyus. The magnetic party at the Auckland Islands was under the dhection of Di"Farr, while Mr. Skey directed the work at Campbell Island. Though the division into two parties was maintained', still the two parties have joined forces in making obse:vations at Pent Pegasus (Stewart Island) and at the Snares, and after our return from Campbell Island the two paitics again combined in observing at several places. A- very valuable aeries of observation's have bo;n the result, thirteen stations having been observed at. On Carnlcy Haibour, Auckland Islands, five stations wore placed, one at the' head of Musgrave inlet, or.c on Adam's Island, about the mid-point of the <northerr> shore of the. "island,, and three others at intermediate positions. To the lay mmdi the mere fact that magnetic observations have been made at those places conveys very little. It may be. then, somewhat instructive to onlar,je upon the nature of the problem, to the solution of which tlisse observations rontiibute, and upon the scientific value in future yearn of the work just accomplished, ard possibly upon' the methods adopted and the instrumental equipment. • , A VALUABLE SUPPLEMENT The Hinemoa left the Bluff at eight <i'clock on Thursday morning, aud proceeded to Port Pegasus, Stewart Island, where a scries of magnetic observations wete made. In pTuvious years observations have been made at Oban, and those at Port Pegasus will be a very valuable supplement to these. Port Pegasus was left the same afternoon, and the Snares, a set of rocky irlets to the south-west of Port Pegasus, were reached at daylight on Friday morning. Landing in the boats, the magnetic observers est up their tent on the summit of Observation Point, over a pog placed there some yea"rs ago ■by the surveyors who were surveying the island with a view to the cf a. : ite for a lighthouse. Incidentally it may be mentioned that several sea-lions and & number of skua gulls had to be evicted before work could be begun. This 'jffocted without casualty on either side, and the sun by some, strange chance happening to be visible for some ten minutes during the da}-, the 'party were n-ule to 'complete the magnetic measurements, and several of our number were enabled by taking turns at observing to take tv short peep at tho curious bird lile on the island. Our eonso of sight was, however, not needed to assure us of the presence of the penguins, and of the tact that tho spot s-elected for observation i»ad been at- no distant date occupied by thorn. A I long pull in the boats saw us safely aboard the steamer, and a start was made for the Auckland Islands, Pore Ross j being Captain Bollon's objective point, ! and our arrival was again heralded by daybreak. The castaways,, of comse, claimed our immediate *attontion and sympathy, and one of thoir number, Charles Eyre, was engaged to act 'as cook to the Campbell Island party, which position he lilted admiiablj''. Captain licllons stayed here but a. short time,, after- assuring himself that the needs of tho shipwrci&cd party weie supplied, rind promi&in™ to return for them fn rome ton or twelve days. Proceeding to th 3( southern end cf the main island, the entire Auckland Island party -was kuded at tho depot, Carnley Harbour, and proceeded to erect their camp, magnetic %york being done that day. Next day Dr. Farr and Mr. Cook, vith Mr. Collyns and the whalcboat and crew, transformed their apparatus lound the point to Camp Cove and observed thcie. discovering that the peaty and sodgy nature of the ground greatjy increased their dilliculties in observing. On Monday a set of observations was made at a iittlo bay to the northward of the depot, and just opposite Musgravo Peninsula ; this time the geologists accompanied them in the whaleboat, and making their way westwards to the mountains, which nowhere appear to exceed 2200 feet in height, the geologists discovered Lake Bennam, a small glacial lake. This day was Gunny in the intcivais of the hail and snow showers, and in the r.fternoon the observers felt the cold \ery niuoh. Nevertheless, a complete seiies of obspruvlions was obtained. .\ COMPLETE SERIES. On. Tuesday, the party proceeded to Adam's Island, and the geologists likewise. It war. a bad day, the hill tops were covered in mist,, and, though the sun was seen for a little while m the morning, in the afternoon rain feJJ continuously. On the Wednesday sun observation? *or chronometer error, i.e., of time, were tnada at tho main camp. On Thursday a third station was obtnined still further to the north on the south-western side of the entrance to Musgrave Harbour, tho day proving good, although showery, and a very complete series of observations was made. To this station Mr. Waite and Dr. Benham accompanied tho party. On Friday tho morning wns occupied in pulling up the North Arm to the fifth station on the Auckland s, a five hours' pull, and this time Mr. Hudson was the only one left at the main ,camp. At the head of the Arm tho party met the botanists and the geologists, who had camped there since Wednesday, ajid who, expecting the boat back on' Thursday, had already put themselves on halfrations. On tho way up the. paity landed on Figure Eight Island, presumably to admire the scenery. Next morning, at 6 a.m., tho magnetic party sot to work to observe, and obtained a very complete set of observations, including nn observation for latitude. ' The main camp was again reached after a long pull at 9 o'clock vhat evening. Tho next day some time observations were made at camp. Monday's plans for going down the harbour were spoiled by high wind, hut lime observations were again made on this day, as also on Tuesday, when the wind was again too fierco, and the mugncticians were absorbed in calculations, when they were interrupted by the arrival of tho Hinemoa from Campbell Island. Camp was struck as quickly as possible, and every one proceeded on board tho steamer. Meanwhile the Campbell Island party had also been busy. Arriving vii Sunday about 10 a.m., the tents and piovisions weie immediately Winded, and proved no light loadk to "swag" from tho beach to the camping place. About noon the rain commenced to fall fast, and after lunch, pitching Lamp wa? completed, cook tent and all, including an extra tent for instiuiiicnt store. On the Monday, rising early upon the genial admonition of our tent mate Charlie, "Now, gentry, rise and bhinc," a site Yias selected for our first inag-

.letic station on Campbell Island, just above Iho camp on a small cleared space well sheltered by a patch of Dracophyllum, or grass-tree. TRANSIT OF VENUS STATION. Observations were continued here the next day. and a complete s>et obtained. From this station could be seen across the harbour the station of the Fiench Transit of Venus Expedition of 1874, marked by a stone bench about 20 feet long, lying east and west. Our first station was almost due west of this Transit of Venus station. On Tuesday evening the magnetic party paid a visit lo tho homestead, about a mile lo tho northward on Tucker's Cove. Hero we were welcomed by 'Mr. Nicholson and his men, who work tho run for Captain Tucker. Tho Messrs. Jackson and Messrs. Norton and Hebeilcy, under contract to shear for Captain Tucker, 'iad not yot commenced work, and so we were «b!o to secure their services and those of two others to carry tho major part of our instruments and observing tout to the northern part of the island, whither we went next morning, arriving on tho north-eastern spur,, of Mount Faye after a fatiguing tramp of four hours in a roaring wind, over peat tussock and moss, up hills, over saddles 1500 ft high, and along ridges, disturbing numerous royal albatrosses making their nests among Iho tussocks, none as yet ha,\ing eggs. Beautiful birds they are indeed, clumsier than cwans on land, more graceful by far on the water or when sailing with stately sweep through the air. At Mount Fayo it was found impossible to finish observing rhat day, as only part of ou»; instruments were carriod back to camp that afternoon, and the observers had another long march across the isiand from camp next day to finish. That afternoon all the rest of the apparatus, chronometer and all, except the observing tent, was carried back to camp, after completing the observations. On {ho eii&uiiig clay ill" Nichoh'oa kindly placed hiß boat at om disposal, and we were able to convey our instruments to our third spot for observation, the si to of the French Transit of Venus Expedition's Observatory. Hither a number of 'the other members of the expedition accompanied us, intent upon a view of the great seaelephant which had been reported near Shoal Point by Dr. Marshall. Their hopes were realised, and ons or two snapshots obtained of the monster, which was judged to be over 20 feet in length. Dip observations, carried on in the meantime, were just concluded when rain came on, and tho party returned to camp. Next morning the magnetic observers returned and ascended Mount Honey, 185 ft, carrying theodolite and cameras to take a few angles Here the wholo island was beneath us, but the coldness and the fierce wind combined made us hasten to set up and tic . down our theodolite, and get through our work as quickly as numb lingers would allow. Thereafter I the descent was quickly made to the Transit Station, where declination and force observations were taken. Tho strong head wind blowing made our little pull back across tho harbour a strenuous one for our small crew. TIME TOO SHORT. Next day, Sunday, a visit was paid the West Bay to view the peculiar formations. Time and azimuth observations of the sun were made in tho afternoon. On Monday three of us &ct out at 4 a.m. for the northern districts with theodolite and cameras, but as soon as the top of Mount Col wan reached wo woro enveloped in thick driving fog,' and it became ovident that no theodolite work could be done that day. Halting for a consultation, we were startled by the Hinomoa's siren, which reached us easily, and sounded quite near at our altitude of loOOft. This of courses sent us back to camp at once, where wo arrived fhorlly after S a.m., nnd immediate preparations for striking camp wore made. Tho Hinemoa herself steamed into view shortly afterwards, and we wore quickly onboard. The mails having boon taicpn on, we bade adieu to our kind friends from the homestead, who long after they had reached tho shoro could be seen waving an improvised flag, consisting of a handkerchief on a whale lance, until we wero lost to sight in tho misty hazo as wo steamed away ito join our 'friends on the Ancklands. Our unanimous opinion on leaving Campbell Island was that it was a pity thai we had had to atlompt to compress sis weeks' work into eight days. Subsequent to taking on board tho, Auckland Wand parly from Carnloy' Harbour, thp captain, atter visiting the depots, decided to stay over night at Norman Inlet, a landlocked harbour some distance to the northward on' tho cast coast. The next morning it was I boats at four o'clock, and combining { foree3 a complete magnetic observation was obtained lief ore eight o'clock al tho head of this inlet. Leaving shortly after eight nnd looking into two other inlet?, j Port lloss was made that afternoon. Il>re I we woro fortunately able to land on EnI derby Island for a few hours, and to observe there. A short run was mode to Disappointment Inland, but the time was too short for any magnetic observations, and after tho interment of the unfortunate first mate, of the Dundonalcl that afternoon, the next morning was devoted to magnetic work in Terror Cove on a beach separated by a smallrocky point from the. observation spot of tho German Expedition of 1870. The piers left by these observers are still intact, though they show tho effe.cts ri thirty-seven years' exposure to the rain and frost. By noon the whole p.u-ty of voyagers wore again on the Ilinomoa, homo ward bound. Soon after leaving the Aucklands, se\eral hauls of the dredge were mado at various depths and tho temperature tit tho sea-boltom noted. Tho final haul, however, in ninety-six fathoms, at twenty miles north of Che island, failed to yield any material, owing to somo mischance. Thi'a occasionally happens in spilo of all precautions.' During the run down from Iho Bluff to the Campbells, the temperature of Iho sea surface was noted every two hours, this work being undertaken by tho magnetic party. INSTRUMENTAL EQUIPMENT. The intrumontal equipment of the Campbell Island parly included a Kew pattern magnetometer No. 1, made by the Cambridge Scientific Instrument Company, the first manufactured by that firm ; also a dip circle No. 147 of the same makers. These wero the magnetic instruments proper. For observing time and azimuth by solar observation a five-inch transit theodolite was used, and a smaller four-inch theodolite of the transit type was also taken. Besidp.'s theso, an excellent chronometer by Molyneux ot proved reliability was used, and the equipment also included an Bxß observing te.nt with a set of light poles, two observing stools of different heights for use with different apparatus, and n collection of minor but essential sundries. Tho Auckland Island parly were similarly equipped with a magnetometer N.A.B.C, of somewhat lighter construction, hitherto used in the magnetic survey, and lent by tho National Physical Laboratory to tl.c Obf>cr\alory. They had also a tacheoinpter ; a reflecting circle with artificial hori/on for time observation, a chronometer by Le\itt, a Kew di;i circle, observing tents, etc-. Thus armed, Hie magnetic parties proceeded to work, their task being to measure, with all possible accmacy, at as many spots in (ho various islands visited as time (and atmospheric conditions) permitted, the values of the nias-

netic declination, the horizontal magnetic force, and the magnetic inclination or flips. From Iho values of theso elements it is easy to calculate the three X.Y.Z. forces, i.e.. the values of tho components of the total magnetic force when resolved in the threo directions, geographical north-south, geographical west-east, and the vertical direction. Theso threo components are at right angles to ono another, and hence cacli is independent of variations in any other ; on this account it in usual in discussing the magnetic condition in any place to consider those three forces separately instead of merely treating of the declination, dip, and horizontal magnetic force, and it is the variation of these three forres according to geographical position and epoch of observation that one studies in the process of making a magnetic survey of any country or ocean area. MAGNETIC INCLINATION. The values of the declination and of the horizontal magnetic force are yielded by observations made with the magnetometer, that on the magnetic inclination is usually observed by means of Ihc dip circle. Most people nowadays arc aware that the compass needle in most places on the earth's surface does not point to the geographical north ; at somo places it points to the east of north, at others to tho west of it, and in different places its direction makes, as a rulo, different angles with the direction of true north. This angle between magnetic and true north constitutes Iho magnetic declination, and is commonly styled among navigators the variation ot the compass. To navigation and the safety of the voyager, an exact knowledge of its value in different parts of the globe is of the utmost importance, as it often nappens that a captain is prevented by cloud for clays together from obtaining those observations of llie sun or stars from which he can compute his exact position, and. also with some degree of accuracy find out his compass error. This is what happened ia the case of the Dundonald, so lamentably wrecked eight- months ago on Disappointment Island. For somo days previous to the wreck they had no sight of sun or str.r to guiclo them, and were dependent entirely upon the accuracy or otherwise of their compasses, upon their knowledge of ths change in tli3 value of the magnetic variation as they ran along the eastward, and upon the exactness of Ihoir reckoning. If any of these failed in that dangerous, rockstrewn sea road, they were, wo can hardly say dependent upon, but rather at the mercy of, good fortune or timely warning of t.ho neighbourhood of land. Their good fortune failed them, and the darkness of the night precluded tho possibility of warning, and thirteen good men lost their lives. We can but ask : Is it not possible that a better knowledge of the magnetic: conditions in those Southern seas would facilitata the navigator's ta&k? There have been ninny other wrecks o:i these islands, and is it not possible that our maptietic knowledge of those parts is defective, and than good fortune and clear weather have in many cases alone been the salvation of the ship '! AN INTERESTING PJtOBLEM. Science may be defined as organised knowledge, and the task of magneticians of the present day in to a large extent lo organise and co-ordinate the multitude of observations that have bean made over tho world. Tho earliest recorded magnetic observations in tho Aucklands were made towards Iho end of the year IGAO by ll. if. ships Erobus and Terror. Since that time, of course, Iho values havo -considerably altered, and it has been known for long that our Magnetic South Polo has been moving northwards slowly in a direction that brings it nearer Now Zealand. It is, of course, a certainty that this stato of affairs will not continue through the ages, but (ha. 1 , the direction of motion will change from time to time, so as to keep tha Alcgnoriu South P,ola probably wilhin tho limits of tho earth's South Polar ice-cap. This problem of iho motion of tho Magnetic South Polo is ono which will continue to interest lnagncliriau.i for many centuries to cc-ine, and all Southern observations lwvo tho most important beaiing upon it. Tho observations jus& macio will, of course, be useful lo the Admiralty, but, besides that, in the interests of 'purescience, they ,nll he extremely valuable as jjart of IS T o\v Zealand's contribution towards (ho magnetic survey of the globs, which magnet icians all "over the world ara striving to complete within about ta:i years. In conclusion, it is only just lo ac knowledge generally the kind way in which all who in any wny could fui-Lher our ends havo do cordially assisted.