[23] As the middle of the glacier moves faster than the sides, and as the line of cleavage is at right angles to the line of tension, lateral crevasses, contrary to what casual deduction might suppose, run backwards from the side of the glacier to the centre.
[24] Provided that the night has been cloudless. An overcast sky, or Föhn, will only produce a very weak crust which gives at once when the sun rises. See footnote on p. [415]. A couple of hours of a cloudless sky is, however, quite enough to produce a good firm crust at night.
CHAPTER X
MOUNTAIN PHOTOGRAPHY
BY SYDNEY SPENCER
It is somewhat superfluous to draw attention to the immense popularity attained by photography in the mountains. Among climbers very few are content to supply their requirements from the work of others, and it may safely be asserted that a camera is almost certain of its place in the outfit of at least three-fourths of the climbing parties of the present day. It is true that the majority of these confine themselves to snapshot photography. This cannot be regarded as a serious form of the art, seeing that it is practically impossible to compose a picture on the diminutive scale of the usual view-finder, and that the films generally used are too uncertain in results. Photographers, also, of this class very rarely trouble to do their own developing.
Excellent work can, however, be done with a hand camera. It has one drawback: the lens is usually a fixture, and provides only one fixed focus, a very important consideration in serious photography. But if the climber decides to use such a hand camera, the following remarks may be of service.
The Camera.
The best form for mountain work is the folding variety. There are innumerable good makes from which to choose. Reflex cameras are too bulky for mountain work. The adjustments should be as simple as possible; and for good work a focussing glass is essential. The lens, by far the most important portion of the camera, should be the very best obtainable. It should be fitted with automatic shutter for instantaneous and time exposures, and also with a lens cap. This latter I have always preferred to use for long exposures in preference to an automatic shutter. It is much easier to avoid shaking the camera in removing a lens cap than it is in pressing the lever of an automatic shutter. The use of a wooden folding tripod with a triangle top I strongly recommend in preference to the brass or aluminium tripod with telescoping legs, since such legs are not sufficiently rigid. I advocate the use of glass plates; and three dark slides, or better still, a changing box to hold six plates or twelve cut films, complete the apparatus. So far, the most satisfactory changing box I have come across is one ‘made in Germany’; of which the description is given on another page of this chapter. An adapter for a film-pack adds very little to the weight, and is a useful addition to the outfit. A hand camera such as I have described is of great service on rock climbs of difficulty, where it is not expedient to embarrass the party by taking the more complicated paraphernalia of a stand camera.
There is a type of climber to whom the merely gymnastic or, we will say, athletic side of climbing is not the sole aim and object of the sport. He is an enthusiastic lover of the marvellous beauties of the mountain recesses, and wishes to take home impressions of the peaks and glaciers as he himself has seen them; for climbers know well that the mountains are ever changing in aspect from one year to another, or even from season to season. He sees and desires to record atmospheric effects which may never be repeated during his climbing experience. He takes his photography seriously, and he is consequently prepared to put himself to a considerable amount of trouble to obtain really artistic records of the scenery amongst which he climbs.
For such a type of climber I decidedly recommend the stand camera in preference to the hand camera. It entails rather more trouble, but this is certain to be justified by the superior results.