Continuing his work as a mathematician, CLD published several mathematical works in 1874 using his real name.

In 1874, he spent a lot of time nursing a dying relative, Charlie Wilcox. On 18 July, he went for a walk to get a rest from nursing, and (as he later recalled in Alice on the Stage):

I was walking on a hillside, alone, one bright summer day, when suddenly there came into my head one line of verse – one solitary line – 'For the Snark was a Boojum, you see'. I knew not what it meant, then: I know not what it means, now; but I wrote it down: and, sometime afterwards, the rest of the stanza occurred to me, that being its last line: and so by degrees, at odd moments during the next year or two, the rest of the poem pieced itself together, that being its last stanza.