Van der Waals, Kamerlingh Onnes. Dutch physicists Johannes Diderik van der Waals (right) and Heike Kamerlingh-Onnes. Van der Waals (1837-1923) developed a formula which accurately predicted the behaviour of gases. This was the first gas law to take account of the gas molecules' size and inter- molecular attraction. Kamerlingh-Onnes (1853- 1926) was the first scientist to liquify helium and discovered that some metals at very low temperatures become superconductors. Both were awarded Nobel Physics Prizes: van der Waals in 1910 and Kamerlingh-Onnes in 1913. Photographed at Kamerlingh-Onnes' low temperature laboratory at Leyden in about 1919.