<p style='text-align: justify;'>This picture was published by David Shoenberg in his book 'Magnetism', Sigma Publishers, 1949 (Plate VIIb). Shoenberg was an expert on magnetism, particularly magnetic effects at low tempertures. He was a research student of Kapitsa's and was a pioneer of the use of the de Haas-van Alphen effect to measure the Fermi surface of materials.</p>