This letter, on the 'Density of Nitrogen', was published in the Letters to the Editor section of 'Nature', a scientific journal. John William Strutt, third Baron Rayleigh (1842-1919), was a nobleman who divided his time between his estates and his scientific studies. He read Mathematics at Cambridge University, where in 1879 he was appointed Profesor of Experimental Physics and Head of the Cavendish Laboratory. From 1887 to 1905 he was also Profesor of Natural Philosophy at the Royal Institution. His experiments in electricity led to the establishment of the standards of resistance, current, and electromotive force. In 1904 he was awarded the Nobel Prize for Physics for his investigations of the densities of gases, and for his discovery of argon.
© Science Museum / Science & Society Picture Library