BAD LIGHT 



Note. — The difficulties of travelling over snow and ice in a bad 

 light are very great. When the light is diffused by clouds or mist, 

 it casts no shadows on the dead white surface, which consequently 

 appears to the eye to be uniformly level. Often as we marched the 

 sledges would be brought up all standing by a sastrugi, or snow mound, 

 caused by the wind, and we would be lucky if we were not tripped up 

 ourselves. Small depressions would escape the eye altogether, and 

 when we thought that we were marching along on a level surface, 

 we would suddenly step down two or three feet. The strain on the 

 eyes under these conditions is very great, and it is when the sun is 

 covered and the weather is thickish that snow blindness is produced. 

 Snow blindness, with which we all become acquainted during the 

 southern journey, is a very painful complaint. The first sign of the 

 approach of the trouble is running at the nose; then the sufferer 

 begins to see double, and his vision gradually becomes blurred. The 

 more painful symptoms appear very soon. The blood-vessels of the 

 eyes swell, making one feel as though sand had got in under the lids, 

 and then the eyes begin to water freely and gradually close up. The 

 best method of relief is to drop some cocaine into the eye, and then 

 apply a powerful astringent, such as sulphate of zinc, in order to 

 reduce the distended blood-vessels. The only way to guard against 

 an attack is to wear goggles the whole time, so that the eyes may not 

 be exposed to the strain caused by the reflection of the light from 

 all quarters. These goggles are made so that the violet rays are cut 

 off, these rays being the most dangerous, but in warm weather, when 

 one is perspiring on account of exertion with the sledges, the glasses 

 fog, and it becomes necessary to take them off frequently in order to 

 wipe them. The goggles we used combined red and green glasses, 

 and so gave a yellow tint to everything and greatly subdued the light. 

 When we removed them, the glare from the surrounding whiteness 

 was intense, and the only relief was to get inside one of the tents, 

 which were made of green material, very restful to the eyes. We 

 noticed that during the spring journey, when the temperature was 

 very low and the sun was glaring on us, we did not suffer from snow 

 blindness. The glare of the light reflected from the snow on bright 

 days places a very severe strain on the eyes, for the rays of the sun 

 are flashed back from millions of crystals. The worst days, as far 

 as snow blindness was concerned, were when the sun was obscured, 

 so that the light came equally from every direction, and the tempera- 

 ture was comparatively high. 



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