But the wireless had a darker side. The one member of the group that had not been selected by Mawson was the replacement wireless operator, Sidney Jeffryes. Jeffryes, who in 1911 had applied unsuccessfully to be an AAE wireless operator, was in the awkward situation of any new person entering an established, close-knit group with its familiar ways and unspoken communications. It was likely to be a difficult year for him.

Finding Jeffryes at Cape Denison on his return from the Far Eastern sledging journey, Mawson expressed no reservations about him. But by May he was feeling uneasy:

On evening of 26th I dozed till near midnight, then on coming out, found Jeffryes asleep – had been practically all evening … It was a great pity about the wireless as it had been a good night. After waking up he got in only a little before Sawyer [the Macquarie Island operator] went to bed. Jeffryes stops up all day – goes for tiring walks, etc, and then is not fit to keep an alert watch during the 8 to 12 hours. This is bad management … Jeffryes is certainly not the man for [scientific study of radio waves] … he appears to have no conception of scientific analysis.

Six weeks later came the first real signs that there was something amiss about Jeffryes. After breakfast on 7 July, he picked a fight with Madigan, who wrestled him to the ground and then confided to Mawson that he thought Jeffryes was ‘a bit off his head’. Mawson put it down to ‘a case of polar depression’ – ‘I trust it will go now.’

It did not. The next day Jeffryes told Bickerton that ‘he would be his second if he did any shooting’. A day later Bage reported to Mawson on the wireless operator’s manic behaviour, then next day Jeffryes asked Mawson to get McLean to treat him for venereal disease. Mawson wrote in his diary: ‘This makes me think he surely must be going off his base … Have put the matter into McLean’s hands.’

McLean administered sleeping draughts and Jeffryes eventually got some much-needed sleep, but on awakening he told Mawson that he ‘wished we would state clearly all the accusations imputed against him’. Mawson tried to pacify him, but the next day he ‘continues bad’, telling Mawson that the men seemed to be sitting in judgment on him.

During July, in the depths of the Cape Denison winter, Bickerton began to take over wireless duties. Then on 27 July Jeffryes announced his ‘resignation’ to Mawson, prompting a conference of the whole group which ended in apparent harmony. Jeffryes continued to operate the wireless in tandem with Bickerton.

But the problems persisted. Early in September. Jeffryes was discovered to have informed Macquarie Island that everyone but him at Cape Denison was insane. Mawson persisted with him, but by the middle of the month he and Bickerton were doing the work with Jeffryes used only as a back-up.

By 25 September Mawson had had enough – ‘I tell him he is in charge of wireless no longer’, and on 4 October he formally dismissed Jeffryes from his post. From then on, Jeffryes, with no formal duties, played a minor part in the life of the group.