MAWSON EXPEDITION

Greymouth Evening Star, 10 December 1929, Page 11

MAWSON EXPEDITION

MUCH RESEARCH WORK. The Discovery with the Mawson Expedition, which is now on its way to 1 the Antarctic to conduct scientific research, carries highly developed instruments for oceanographic observations. With these the party can study the depths, temperatures, composition, and current movements and life of the sea traversed. The Discovery, writes Sir Douglas Mawson, in the Adelaide “Observer,” is fitted with three devices to test the depths of the seal ’ Firstly, a Kelvin sounding machine driven by electro-motor, is supplied for use in shallow water and is of special value for navigation purposes when steaming close to land. It can be operated while the ship is in motion. A glass tube sealed at the upper end and attached to a strong multiplestrand wire is carried to the bottom by a heavy weight. The depth reached is calculated from the degree of compression to which the air in the tube has been subjected owing to the pressure of the water lying above pit. For deeper water, a machine is installed on the forecastle head. The drum carries 500 fathoms of wire of 0.028 inch diameter, with a breaking strain of 2401 b. For. the. present voyage there is used a new instrument, by the use of which the depth of the ocean, even when it amounts to several thousand fathoms, can at any time be ascertained in a few seconds.

The measure of the depths depends upon the time interval taken for a sound to travel to the bottom of the sea and back again. The sound waves communicated to the water are made by an hydraulic hammer located in a sealed metal tank set in the bottom of the vessel at the forward end. The returning sound waves echoed from the flooi of the sea are recorded in a delicately constructed and carefully tuned, electrically-recording receiver synchronised with the dispatch mechanism and set in the hull near the after end of the vessel. It is anticipated that by the aid of these instruments the contour and nature of the sea-floor along the route to be traversed by the ship will be revealed.

TEMPERATURE OF SEA WATER. The body of the ocean is composed of many-layers of water, each quite distinct so far as temperature and salinity are concerned. These separate water strata have each their own independent movement, just as have the various layers of the atmosphere. The current movements in each of these layers is, therefore, a further subject for study. The temperature of the surface waters will be recorded- continuously as a graph, drawn on a chart by an electrically-operated distance thermometer set in the hull of the ship. In the case of the deeper waters, records will be obtained at as many stations as possible, observing at frequent intervals from the surface to the bottom. The water samples from various depths are examined quantitatively in regard to the more important constituents contained therein. Dr Stanley Kemp’s observations in

the neighbourhood of South Georgia have shown that, where nitrogen arid phosphorous are abundant in the surface waters these fertilising constituents are just as stimulating to plant life in' the seas as they are valuable to the farmers’ crops on the land. With the increase of microscopic plant forms in the sea waters, there results in turn a vast local increase in the small free-swimming crustacean life which constitutes the principal food of the southern whales. Therefore, waters abnormally rich in nitrogen and phosphorous are potential whaling grounds. The most interesting department of oceanography is that dealing with the living contents of the waters. This is usually considered •in two main groups, the life on the sea bottom, and the life of the surface and intermediate waters. The trawls loaded with spoil from the sea floor are landed on a special dredging platform at the stern of the vessel. The biological material captured by these various methods is dealt with in the deck laboratory. The zoologists will also have a busy and interesting, time collecting and recording the abundant sear and bird life of the far south. All these creatures support both internal and external parasites, consequently they have a secondary interest no less important than that of the hosts themselves. They are not merely subjects for the taxidermist, but offer interesting possibilities for the parasitologist. The sub-antarctic islands, besides teeming with creatures of fur and feather, also support an appreciable

amount and variety of plant life, an opportunity not afforded on the Antarctic mainland. The inclusion in the equipment of a small aeroplane greatly increases our range of observation, a provision which will be valuable in plotting the distribution of the pack ice and in locating land. By frequent ascents to heights of 10,000 ft and more, it is also expected that the aviators will ftirnish the meteorologist with valuable upper-air data. Not least in importance of the instrument equipment is the photo-

graphic section, which amply provides for the taking of moving and still pictures of all objects and incidents worthy of record. The medical officer is to conduct bacteriological studies and inquiries into problems connected with metabolism as affected by the unusual conditions of food and life in Antarctica. A useful item of the medical equipment is an X-ray apparatus, which will be invaluable should any bones be broken in the conduct of the exploration by land, sea, or air.