The occurrence of isolated ice- or snow-covered summits is reviewed. Their existence appears in the first place to be a function of their breadth in relation to the altitude of the firn line on adjacent glaciers; other factors remain to be discussed. Light may thus be thrown on questions of past glaciation of rounded summits in critical areas, and notably on the amount of precipitation then prevailing.

Deep, partly snow-filled gullies cutting the sea cliffs of part of the Vestspitsbergen strandflat are noted. They do not appear to have been cut by streams, and it is suggested that a process of frost action and snowpatch erosion has been largely responsible for their formation.

A short note on glacial recession in part of Vestspitsbergen is added.

Sea ice research has reached a critical point in its development. In place of a geographical statistical trend there is now a geophysical approach. Whereas the main problem has been the explanation of the phenomena of sea ice in space and time, more and more attention is being devoted to the connexion between the state of the ice and the changing conditions in the water and the air.

The Coleman Glacier on Mt. Baker in the State of Washington began to advance about 1949 after a long period of rapid retreat. Since that year the terminus has advanced continuously a total of about 300 m. and considerable thickening of the entire glacier has occurred. The continued advance of the Coleman Glacier and other evidence are interpreted as manifestations of a trend during the last decade towards a slightly cooler and moist climate in the north-west of the United States.

It is well known that an empty hole in a glacier will fill in if it is more than some 15 to 20 m. deep, due to the rapid variation of strain rate with shear stress. It is pointed out that a water-filled hole or lake will tend to enlarge itself by the same mechanism, if it is more than 150 to 200 m. deep. This phenomenon is believed to be responsible for the periodical and complete emptying of some glacier lakes, such as has been reported for the Tulsequah Lake in British Columbia, and Graenalón and Grilmsvötn in Iceland.

A mixture of approximately one part of water to two parts of kaolin (china clay) has proved suitable for making model glaciers on scales between 1 : 1000 and 1 : 10,000. The kaolin “glaciers” crevasse and flow realistically, and slide on their beds. They serve well for qualitative demonstrations, and some simple preliminary quantitative experiments suggest that they may also be useful for this purpose.

Firn and ice thickness measurements were carried out by seismic refraction and reflection methods on a flat col of the highland snowfields of the Penny Ice Cap and on a medium-sized valley glacier (Highway Glacier). The longitudinal wave velocities were found to vary from some 1000 m./sec. (3280 ft./sec.) in firn to 3810 m.,/sec. (12,500 ft./sec.) in ice and approximately 6000 m.% sec. (20,000 ft./sec.) in the bedrock (gneiss). The thickness of firn and ice at the firn col was found to be 254 m. (834 ft.). On Highway Glacier some 80 reflections were evaluated, giving position, dip and strike of the bedrock surface. A longitudinal profile of Highway Glacier from the junction of three main tributary glaciers to the tongue is given; the ice thickness slowly decreases. At the junction, the bedrock is 400 m. (1310 ft.) deep, there is no deep basin as might be expected from the surface features. The mean slope of the glacier surface is about 3° of arc and of the bed about 1°.

Snow crystals were received on the collodion film of the holder of an electron microscope, and made to sublimate without melting. These specimens were investigated under an electron microscope. One solid nucleus was always observed in the central portion of a snow crystal. These centre nuclei were of sizes between 0.5 and 8μ. Most of them were presumed to be kaolin, clay or carbon particles; some were considered to be micro-organisms. In the other parts of snow crystals numerous smaller nuclei were observed, whose dimensions were of the order of those of condensation nuclei. These condensation nuclei were found to be of two kinds, the larger ones most frequently having a diameter of about 0.15μ, the smaller ones of about 0.05μ. A new theory was proposed from the data of the electron microscopic studies and those of the conditions of formation of snow crystals. In this theory it is proposed that minute water droplets of 1μ or so play an important rôls in the process of snow crystal growth.

It has been found that in the cold firn of the Greenland Ice Sheet a direct relationship exists between the specific gravity of a layer and its “resistance to penetration” as measured with a Rammsonde. Corrections which should be applied to the measured “resistance” to allow for the frictional resistance of the walls of the hole on the Rammsonde tube are discussed. In certain circumstances these corrections can be estimated with reasonable accuracy for tube lengths up to three metres. The statistical method of obtaining the relationships between “resistance” and specific gravity is briefly outlined, and the effect of the size of the snow grains is also considered. It is shown that under these particular conditions it is possible, from measurements of “resistance”, to estimate the specific gravity of a firn layer with a standard error of 0.04, when the specific gravity of the sample is in the range 0.3 to 0.57.

Ernst Sorge, a member of Wegener’s Greenland Expedition 1930–31, discovered an important law on the densification of snow in high polar glaciers. It is here given a simple mathematical form and some of its implications are formulated and discussed. Apart from its significance to glaciology and snow mechanics, Sorge’s law should also be useful in the study of consolidation of accumulating fine-grained lacustrian and oceanic sediments.

The wave of cold temperature, which begins to propagate into a snow field during the winter, may be considerably enhanced by the thermal blanketing of snow accumulating on the surface. This effect is discussed theoretically by means of calculations based on the mathematical theory of the conduction of heat in solids. The results of these calculations show that for an assumed steady velocity of accumulation at the rate of 4 meters/year or 8 meters/year, the winter cold wave should assume significantly larger proportions than in the absence of accumulation.

Planimetry of the 15 maps of scale 1:1,000,000 of the World Aeronautical Chart, U.S.A.F., gives 1.726 × 106 km.2 for the surface area of the Greenland Ice Sheet. The hypsometric curve obtained by measuring the area between contours at 1000-ft. (305 m.) intervals with a planimeter gives 2135 m. for the mean height of the ice sheet. The normal area distribution curve of the ice sheet shows that is certainly in the “Inland Ice” type in Ahlmann’s classification. The mean firn line of the ice sheet is at a height of 1390 m. The discharge from the glaciers in the form of icebergs is estimated to be 215 km.3 of water per year, and the nett balance of the ice cap is negative and about 100 km.3 of water per year.