The heating element, formed of three tantalum coils baked into heat-resisting clay, was screwed to the end of the steel tube that was to form the lining of the hole, and a tripod was set up to suspend the drill above the hole. The element generated 2.5 kW at 330 V, and was powered by a cable that ran down the steel tube. It was connected to power at the Sphinx Observatory by a cable laid across the snow. Drilling began in July 1948, and after two weeks the hole was successfully drilled to the bed of the glacier at a depth of 137 m. There were some additional delays: twice the tube had to be hauled back out of the hole—once to remove a dropped spanner, and once because the heating element burned out. Inclinometer readings were taken in August and September 1948, and again in October 1949 and September 1950; the results showed that the borehole was curving forward as time passed, implying that the velocity of the ice decreased from the surface towards the bed.