In connection with my glaciological researches in the Horung Massif in Norway,' which have been carried on for many years, the Meteorological Office of that country, under the direction of Dr. J. Bjerknes, has built a small observatory on the summit of Mount Fanaraken, which belongs to the Horung Massif. This massif is situated in Jotunheim, the greatest high-fell region in central Norway, 20 kilometers from the innermost part of the Sogne Fjord and 180 kilometers from the open sea. On June 23, 1928, I reached the observatory, 2,050 meters above sea-level, and lived there for nine days. During this period the temperature varied between + i° and -5° C., the wind was from the southwest the whole time, and, with the exception of one or two intervals lasting a few hours, the summit was covered with clouds. These climatic conditions were exceptional for the end of June and the beginning of July. They were more in accordance with the conditions prevailing in October and November. A matter of special interest during my stay on the summit was the immense formation of hoarfrost. When the weather was calm, only a slight formation took place; but as soon as the southwesterly wind began, there were deposited on the windward side of all the objects above the ground thick sprays of hoarfrost. This was especially the case on surfaces which were not previously covered with snow, such as the walls and backstays of the observatory, steeply projecting parts of the rock-ground, etc. This formation of hoarfrost increased with the rising force of wind and attained its culmination during the storm that raged from the afternoon of June 29 until the morning of July 2. The anemometer of the observatory was not in working order; but I estimated the force of the wind, when it was greatest, at about 25-30 meters per second; the mean