WIRELESS TO MAWSON.

Dominion, Volume 7, Issue 1963, 21 January 1914, Page 5

WIRELESS TO MAWSON.

' THE SERVICE IS SUSPENDED. EFFECT OF THE SUN'S RAYS, ' Much anxiety has been manifested of late in Australia by people who have relatives or friends among the members of the Alawsoii Expedition owing to the suspension of the wireless communication with Adelie Land. J?'or tho last ten -weeks the wireless station ;it Macquario Island—which is a sort of half-way station, has held a whole sheaf of otliorgrams, but all attempts to get into t-oueli with Dr. Mawson's station in Adelie Land have proved fruitless. The Sydney "Telegraph"' explains that there is, however, not tho slightest ground for- uneasiness. It- not expected by anyone who understands 'wireless telegraphy that tho 11-kilowatt station at Maequarie Island would be able to maintain communication with Adelie Land when summer set-in. The reason for that is that the ionisatioii' of the sun's rays has the effect of reducing the power of tho Hertzian waves, and thus also reducing the distance over which the wireless signals can bo detected and distinguished. During the whole of tho winter months. Dr. Mawson had the consolation of being in touch with the world. He could "speak" by wireless, with his friends with tho case that people in adjoining States of tho Commonwealth caii communicate by means of the ordinary telegram. Tho service with Adelie Land throughout tho winter months was excellent. Every student of wireless knows that wireless signals will travel five times as far at night'as m .tho. daytime, for the reason that at night there is no sunlight to diminish the strength of the Hertzian waves. In the same way the Antarctic being onvcloped in darkness during tho inter, communication, which was easily maintained over the 9-10 miles bej\\een Adelio Land and the Macciuarie lslami in the winter months, is impossible when the. messages have to travel through sunlight. At Dr. Maw son a i case at tho present time the sun is above the horizon for nearly a out ot the 24 hours, and consequently it is : impossible for the wireless waves to encompass tho distance. Had ihero been a 5-kilowatt station eteeted atAdelie Land, it would have been pos- j siblo to have maintained communica- ] tiou' throughout summer and w.mter, but. like the station at Macquane Is- j land, there is only a 11-kilowaU plant erected in the far south. It is, therefore, provable that the lt-oxt news received from Dr. MaVrson will lie that he has arrived at Adelaide, though possible the Aurora may be first sighted at Cape Borda lighthouse, which is situated on Kangaroo Island, the southernmost part of South Austialia. This nows may be expected towards the end of next month. The Aurora left Maequarie Island in tho first week of December. \\ hilo there she took on board the four,member's of the Mawson Expedition who had up till that time performed scientific work at that post Tho station at M.cquarie Island is bcii.r retained by the Commonwealth Bureau for meteorological purposes. it was expected that tho Aurora would leach Dr Mawson's headquarter* at Adelio Land on December 12: Some time would be occupied in taking on board the instruments arid. bMl<y™« ! and other specimens, and after t at the vessel would pursue scientific im<vU gations, returning to Australia about the end of February.