Delighted to hear that JD’s research is continuing. CD has heard that JD’s paper will at last be published. He is flattered by the form [as a letter addressed to CD] of communication. [See 1651a and 1819a, published in Phil. Trans. R. S. 146 (1856): 21–9 and Proc. R. S. London 8 (1856–7): 27–33.]