I send by the carrier tonight a long paper for the Society.2 Will you have the kindness to send me one line to say that it has been received. I will write tomorrow—the post is going.3
A description of this letter was published in Correspondence vol. 13. The year is established by the reference to the ‘long paper’ sent to the Linnean Society (see n. 2, below), and by the relationship between this letter and the letter to J. D. Hooker, 19 January [1865] (Correspondence vol. 13).