Has been invited to lecture at the Royal Institution by Spottiswoode. Discusses subjects he might deal with and his reasons for attempting it.

Tells of a complicated case of a double sale of a living.

Huxley says F. M. Balfour passed brilliantly.

Advice to GHD on whether to accept invitation to lecture at the Royal Institution.

Murray has sent the Quarterly Review issue. CD has told Murray that he is convinced Mivart is the author and what he thinks of him.

Sends index [of Descent, 2d ed.] with instructions for proof-reading.

Asks GHD questions about heat transmission; he wants to use it as an analogy to illustrate transmission of motor impulses through leaves of Dionaea.

GHD explains conduction, radiation, and convection.

His paper on political economy for Royal Institution lecture has reached 60 pages. Plans to send it to Contemporary Review.

Writes about instructions to compositor and return of proofs [of Descent]. Requests return of 2d volume of Descent, to which he may want to refer.

Thanks GHD for clear lecture on heat.

Will keep paper on proportion of sexes, in case GHD wants it again.

Wants him to translate some pages of Swedish or Norwegian sent by A. W. Malm, "a good man".

Glad to see the statistical paper ["Theory of exchange value", Fortn. Rev. n.s. 17 (1875): 243–53].