July 17, 1890] 



NA TURE 



273 



fan. Under no conditions should any but safety-lamps 

 be used in coal holds or bunkers. 



A discussion followed, and the proceedings closed with 

 a vote of thanks to the lecturer. 



A WINTER EXPEDITION TO THE 

 SONNBLICK> 



IT is not often that an Alpinist finds leisure to spend 

 a month in winter at an altitude of 10,154 feet above 

 the level of the sea. It may, therefore, interest the mem- 

 bers of the Alpine Club, to have the experiences of one 

 who, though not a member of their Society, yet was for- 

 tunate enough to make the unusual ascent, which was 

 chiefly undertaken in the interests of science. 



It is well known that since 1886, thanks to the united 

 efforts of the Alpine Club, and of the Imperial Austrian 

 Meteorological Society, and in a special manner to the 

 energy and public spirit of Herr Ignaz Rojacher, there is 

 now a thoroughly equipped Observatory on the highest 

 peak of the Sonnblick. This Observatory has been 

 established with the view of affording to students of 

 natural science, physics, astronomy, and meteorology, the 

 means of making such observations as are only practi- 

 cable at great heights ; and of providing them with 

 accommodation in a part of the building which has been 

 named by the owner " The Study." 



In carrying on certain inquiries which are only to be 

 solved on high mountains, I had for this purpose spent 

 a month in the summer of 188 1 on the Hoch Obir (6716 

 feet) in Carinthia, and I determined the first winter 

 after the erection of the Observatory on the Sonnblick 

 still further to resume the investigations in a situation 

 which afforded aclear,cold, winter atmosphere, which was 

 absolutely necessary. I was unfortunately unable to realize 

 my intention the first winter (1887), which was the more 

 to be regretted inasmuch as the winter of 1887, and 

 especially the month of February, was unusually fine, 

 whereas that of 1888 was the severest ever known. The 

 " oldest inhabitant " of those parts had no remembrance of 

 such heavy falls of snow and such dark and stormy 

 weather as we experienced in the February of 1888 — the 

 month for which I had made all my arrangements for an 

 expedition to the Sonnblick. 



My expedition was undertaken with the following 

 objects :— (i) To investigate the radiation of the earth into 

 space, and the irradiation of the atmosphere upon the 

 earth's surface, in order to ascertain, more accurately 

 than had hitherto been done, the temperature of the aerial 

 envelope of the earth. (2) To investigate the question of 

 the blueness of the sky. (3) To discover whether the 

 sparkle of the stars was altogether due to the lower strata 

 of air. Having had a grant from the Imperial Academy of 

 Sciences in Vienna for the purpose, I succeeded in enlist- 

 ing the services of Dr. Trabert, a young indefatigable man 

 of science, as assistant, to make simultaneous observations 

 on the Rauris, whilst I observed on the Sonnblick. 



We reached Lend on the morning of February 3, where 

 we handed over our seven cases of scientific instruments, 

 and my provisions for a month's sojourn on the Sonnblick, 

 to Herr Rojacher's men, who conveyed the whole on a 

 couple of sledges through Embach to Rauris ; we 

 driving to Kitzloch Rauris, where we found Herr Roja- 

 cher awaiting us, and, after a tough climb of an hour and 

 a quarter up the mountain pass of Kitzloch, we proceeded 

 by sledge to Rauris. 



^ This first day was perhaps the finest during our stay 

 in the Rauris Mountains ; on the next, it began to snow ; 

 and it was in a heavy snow-storm that I had to set out 

 for Kolm ; and so heavy was it, that it was with the 

 greatest difficulty that Rojacher and I, in our sledge, 

 followed by the Rossknccht with my baggage, were 



' By Dr. J. M. Pernter, of ihe Imperial Academy of Sciences in Vienna. 

 NO. 108 1, VOL. 42] 



enabled to reach the Bodenhaus. From thence, through 

 the woods, to Kreuzbichl, the snow fell thicker and 

 thicker, and it seemed as if we should never get to our 

 destination. Beyond Kreuzbichl there was no path of 

 any sort, and we had simply to wade through the deep 

 snow for fully an hour, before we reached Kolm, Herr 

 Rojacher's residence (5249 feet). On my arrival, I was 

 just in time to telephone to Rauris that I had reached so 

 far in safety, the telephone communication being im- 

 mediately thereafter interrupted. That journey from 

 Rauris to Kolm had given me some idea of what a snow- 

 storm in those regions meant. The avalanches caused 

 by the weight of snow, had broken down the telephone 

 wires, completely burying them, and, in one place, 

 carrying them away for a distance of over two kilo- 

 metres. 



The Rossknecht had just reached Bodenhaus, but was 

 utterly unable to push on further. It was four days 

 before all my cases could be brought on to Kolm ; and 

 then the men had to carry them on their backs. Here 

 was I, cut off from the world, snowed up at Kolm, and 

 with little apparent prospect of getting to the Sonnblick ; 

 the snow falling faster and faster for four whole days, 

 without intermission. But I was thankful enough to have 

 reached there, for the valley beneath was laid waste with 

 avalanches, making the roads impassable. However, the 

 five days in which I was blockaded at Kolm were any- 

 thing but wearisome. I could well have undergone a 

 longer imprisonment with a companion so ingenious and 

 intelligent as Rojacher. He had always some interesting 

 subject to discuss, or new problem to set concerning the 

 Tauern range. What perhaps interested me the most 

 were his descriptions of winter life in this inhospitable 

 altitude— its pleasures and difficulties, and particularly 

 his explanation of the Lahnen, the local word for 

 avalanches. 



There are two kinds of Lahnen, he explained, Wind- 

 lahnen or Windsbretter (wind avalanches), and Jauk or 

 Grundlahnen (ground avalanches). The first belong 

 exclusively to winter; the second to spring. These last are 

 the avalanches of which people who live far out of the 

 reach of avalanches have formed the one and sole idea 

 of their nature and composition, thus confounding the 

 two. They are, however, totally different. 



The action of the ground, or Jauk, lahn, as its name 

 denotes, is to break away from its base on the ground ; 

 and, as its second name denotes, mostly in consequence 

 of warmer temperature, i.e. Jauk, south wind. It is com- 

 posed of a huge mass of melting snow saturated with 

 thaw water, that, restrained by the enormous friction of 

 the earth, carries slowly along with it everything that 

 impedes its course. It is set in motion when the rnoisture 

 of the thawing ground has sufficiently diminished the 

 earth's friction which has hitherto held it back. It needs 

 no propelling medium ; its own weight causes it to slide. 

 The prevailing idea that any small particles of snow set 

 primarily rolling by a bird, or any such unimportant 

 agency, can gradually increase to the dimensions of an 

 avalanche, is a pure fallacy. The rolling is a secondary 

 matter ; the primary agent in an avalanche is its sliding. 

 They travel slowly, Rojacher said— that is, there is mostly 

 time for escape on first hearing the roar of the heavy 

 falling mass ; with the Windlahn is no such hope, as both 

 Rojacher, and all others whom I questioned, assured me. 

 The Windlahn he explained in the following manner. 

 The first falls of winter snow fill up all inequalities of the 

 surface. If it lies for a time, it consolidates and forms 

 an even, slippery surface. More snow falling upon this 

 smooth surface has a tendency, by its own weight, to slide 

 off. This is certain to occur if after a heavy fall of snow 

 the new layer has acquired such weight that its pressure 

 overcomes the slight resistance of the underlying stratum, 

 and any chance obstacles that hold it back. As soon as 

 the top pressure is great enough to start a fissure, the 



