The caption above reads, 'Balance on one foot, raising the other leg until the knee is in a straight line with the hip. Now straighten out the leg so that the top and hip are in a straight line, gradually swing the leg from the forward position until it is directly behind you.'
Try it, and see if you can maintain the cool demeanour of the captain, in his natty hand knit, knee-highs and immaculate hair. The photography gives him a rather strange, guru-like aura.
Even more guru-like in this photo, our hero demonstrates another exercise, for when we have the first under our belts: 'Stand on one leg, push the other out in front so that the toe is in line with the hip. Hold this position and gradually sink down as near the floor as possible. From the position shown here, gradually straighten up, still holding the unemployed leg (!) straight in front, until original position is gained.' Nothing is said about the delicate hand gestures. More from 'Skating' later in the year.
(Many thanks to Caroline Holden-Hotopf, who drew my attention to this fine volume.)