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.

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.

At Eqe, on the western border of the Greenland Ice Cap, measurements of the crystals by Seligman’s method give a mean crystal diameter of 2.16 cm. at a place where the ice velocity is ceto m.fday. The “heterometry index” measured from granulometric curves by Cailleux’s method shows that melting, active ice crystals have reasonably homogeneous dimensions, with a mean diameter from 2 to 2.4 cm.

Penitents are observed on all the snow fields and glaciers of the Santiago Andesbetween 4000 and 5200 m. They are caused by the prolonged action of the sun in adry and cold atmosphere, The sublimation of the snow or ice allows the crests tomaintain their temperature below 0° C., while in the spaces or passagesbetween the penitents, where radiation is concentrated and removal of watervapour not so easy, melting takes place. This hypothesis is justified by a briefstudy of the climate of the high Cordillera of Santiago; this study has beenattempted for the first time with the help of meteorological informationobtained from La Cumbre (3837 m.).

The first stage of the penitents is a form of “micropenitent,”similar to that observed at the end of the winter below 3500 m. Thesemicropenitents frequently come from crusted snow which has cracked. The compactice penitents are directly formed from ice, as is proved by the existence of icemicropenitents.

The Penny Ice Cap on the Cumberland Peninsula of Baffin Island, N.W.T., Canada, was studied during the summer of 1953. This ice cap has an area of some 5900 sq. km. and rests on a 2000 m. high mountain range. It has ten major outflowing glaciers, three of which reach the sea in fjords. The progress of snow accumulation and ablation and the net annual loss or gain of water at various altitudes on the ice cap are recorded. The firn line is at about 1550 m. and the outflowing glaciers are noticeably retreating.