left Lyttelton on Friday 14/12/62 on U.S.S. Arneb, and arrived in McMurdo Sould on Saturday 29/12. We stayed at Scott Base until Thursday 3/1/63, waiting for gear which was not unloaded from Arneb until 2/1. Benseman and Shirtcliffe arrived at Lake Bonney p.m. 3/1 with most of the gear, Popplewell bringing the remainder in a second helicopter flight in the evening, and base was set up in a hut at the eastern end of the lake.

4/1 and 5/1 were spent overcoming initial difficulties with ice drills and measuring techniques. 6/1 was again unproductive, much of the day being spent in the hut preparing for chemical analyses and trying without success to remedy the internal disorders of potentiometer and galvanometer.

From an early start on 7/1 good progress was made using spare measuring equipment. The daily routine consisted of making measurements in 3 holes before lunch and drilling another 3 during the afternoon, thus allowing at least 12 hours to elapse after drilling a hole before any measurements were made in it. The plan was to drill an initial line of 12 holes in the eastern half of the lake, north of the centre line, followed by 1 hole in the narrow neck joining the two halves, 3 in the western half of the lake, and finally a line of 5 in the eastern half, south of the centre line. This would have taken seven days, leaving four days at the end for such additional measurements as may have been found necessary, bottom sampling, photography of ice formations etc.

This programme was based on the initial request for two weeks in the field. Owing to transport difficulties time in the field had to be cut short, and we left p.m. Wednesday 9/1.

Results.

In all, temperature profiles were measured in 11 holes. Of these the first two were shallow and of limited use, the last included readings at a few depths only, and one contained an equipment error induced by last-minute haste. The remaining 7 profiles should provide good information.

A radiation profile was measured once only, and was hampered by cloud.

While Benseman and Shirtcliffe were engaged on these measurements, Popplewell investigated and collected samples from melt streams at the eastern end of the lake, and also a valuable set of samples from one hole in the lake. Chloride analysis was completed on these samples in the field as insurance against their loss, and further analysis will be continuing for some time in the laboratory.

The initial conclusion is that the high temperatures in the lake are due to the trapping of solar energy, but the details are not yet clear.

Work yet to be done.

It would also be desirable to devote some time to a study of the ice cover and the mechanism of evaporation from it, get an estimate of the annual water inflow and salt accretion, take bottom samples, etc.

The total work remaining would probably occupy 3 men for a week from the time a routine was established - say 10 days in all.