GLOBE FOR CANTERBURY MUSEUM

Press, Volume XC, Issue 27466, 28 September 1954, Page 8

GLOBE FOR CANTERBURY MUSEUM

Arrival About A Year From Now SIXTH OF ITS KIND IN THE . WORLD [Specially Written lor “The Press”) (By ARTHUR LUSH, 8.E.l An outstanding exhibit in the Geology Hall of the enlarged Canterbury Museum will be an “Orthographical Globe” of about six feet diameter, with the land masses shown in relief. Few globes have yet been made to this model. The first was completed in 1936, and was exhibited in the Royal Scottish Museum, Edinburgh. Others have since been supplied to the Royal Air Force College, Cranwell, Lincolnshire, to Eton College, to the Geological and Survey Museum, South Kensington, and to the Massachusetts Institute of Technology. Ours will be the sixth of its kind, the first in the Southern Hemisphere, and the first to be suspended from above, so as to give a visual impression of the globe “floating” in space.

This type of mounting is shown in a photograph of a model, prepared some years ago, when the proposal was first under consideration for our museum. An ordinary school globe had to be used for the model, instead of a globe with the surface in relief, but it shows the shaft extending to an overhead support, and the South Polar regions clear of any mechanism. In our case, this has a further advantage, besides the visual effect already mentioned. Canterbury Museum has particular associations with South Polar exploration, and exhibits include various items from the Scott Expedition. Visitors will naturally like to be able to see for themselves the part of the globe upon which Scott’s route may be traced. To provide for observation of these Antarctic areas, a stepped recess will be provided, below the globe, and a pedestal light is proposed to light up the lowest part, which would otherwise be in shadow. When the model was made, there was an idea of mounting the globe with tts centre at about six feet above floor level. It was also desired to have about seven feet clear space below the globe, for observers of the Antarctic areas, and these two conditions led to the provision, on the model, of a recess below the globe, with five steps. On the -“vised design, the scale of the flol as been modified, and the eij the centre raised to eight feet above floor level, so that fewer steps will be needed. The equatorial regions will be observable from floor level, in any case, and the Arctic areas of the globe from a cantilever platform which Is to be provided with a stairway beside a side wall of the gallery.

Relief Will Stand Out More Clearly Two scales are used for the globe, so that the relief work shall stand out clearly. The vertical scale has been made 20 times the horizontal —that is to say, the vertical scale is in the proportion of one inch to 30,000 ft. The horizontal scale is 1 to 7,197,000, or one inch to 114 miles. At sea level, the model is made spherical: no attempt has been made to show the difference between polar and equatorial diameters, as this would be only o.llBin. and so quite unnoticeable. The diameter at the surface of the oceans is 5 feet 10| inches. From this base, the height of the European Alps stands out about half an inch, and of Everest, about an inch. This is found to give quite an imposing effect, without too much over-steepening of the slopes. The axis of the globe is inclined at 23 i degrees to the ecliptic. That is to say, if the museum floor represents, to us, part of the plane upon which the earth’s orbit may be traced round the

sun, then the axis of the globe will have its correct inclination to that plane. This is important, particularly for teaching purposes. The globe is to be illuminated by projector lights set at suitable places on the walls of the loom, to give, as nearly as may be practicable, an impression of the effect of light reaching the earth from the sun, which is so far away that it gives what we may call parallel lighting: the rays on both sides of the earth are almost exactly parallel. Though we cannot readily reproduce this exact effect, we can get something like it by providing projectors in pairs, spaced at a distance apart about equal to the diameter of the globe. Thus when one pair of projectors is turned, on, the globe will show conditions of sunrise, and sunset, day and night, for the summer of the northern hemisphere and the winter of the southern hemisphere. The opposite pair of projectors will give the reverse condition, with northern winter and southern summer. The intermediate pair will show the conditions at the equinox. A simple extension of the same system of lighting could show the long days and nights within the Arctic and Antarctic circles, and the phenomenon of the Midnight Sun.

To show these changing conditions to the best advantage, it is proposed, as soon as funds allow, to add mechanism to rotate the globe once in each two and a half minutes.

The “Why” of a Navigator’s Course It is not possible, with ordinary flat maps, and particularly with those on the familiar Mercator’s projection, to give a correct idea of the relative positions of places on the earth, and of the shortest distance between certain points. The provision of a large globe will do more than show distances that are used on air routes. It will help people to understand why, for instance, a navigator setting a course from Cape Town to New Zealand'chooses a route that, goes so far south, instead of going on what Mercator’s projection seems like “straight across.” It will also show that the shortest distance from New Zealand to England is over the North Pole—a route that may conceivably be used some day. The new globe will be shipped to New Zealand, assembled in one large sphere. Although it is a large globe, the scale adopted will result in New Zealand appearing with a length of a little more than eight inches, and so we cannot expect our own mountains to be shown in any great detail. -The material of the globe, however, will be such as to permit museum craftsmen to make any alterations or additions that may result from newer dis-

coveries or more detailed exploration or surveying. Whether additional de-

tail will be shown on our New Zealand mountains will depend upon several things—whether contour plans become available, whether the modifications are considered worth-while, and whether the museum will be given the financial support that is needed for many most desirable undertakings to be put in hand. Many of these may be more urgent than extra detail upon our small area of the globe.