Copy letter from Francis Alexander Towle, Assistant Secretary of the Royal Society; to Professor [Heike] Kamerlingh Onnes, FRS Apologises for forgetting to add a statement to the proof copy of L. C. Jackson's paper, 'Investigations on Paramagnetism at Low Temperatures, sent to Professor [Heike] Kamerlingh Onnes. The statement is that the paper was a communication from the Laboratory of Physics of the University of Leiden. 16 October 1923