Summary

Sends, with CD’s approval, a clarification of CD’s explanation of how useless organs might diminish [see 9061]. Using Quetelet’s law of normal distribution GHD shows how horns of cattle, having become useless, would gradually diminish and finally disappear.

Summary

Has decided to send the letter ["Variation of organs", Nature 8 (1873): 505].

Writes of his poor health and problems of settling in at Trinity.

Summary

Asks GHD whether he can tell him what inclination a polished or waxy leaf ought to hold to the horizon in order to let vertical rain rebound off as much as possible.

Summary

On bodies of varying elasticity bouncing off inclined planes [see 9096].

Summary

CD gives his criticisms of GHD’s essay on religion and the moral sense. Urges him to delay publishing for some months and then to consider whether it is new and important enough to counterbalance the effects of its publication. J. S. Mill would never have influenced the age as he has done had he not refrained from expressing his religious convictions. Cites John Morley’s Life of Voltaire [1872]: direct attacks produce little effect; real good comes from slow and silent side attacks. "My advice is to pause, pause, pause."

Summary

"It is a fearfully difficult moral problem about speaking out on religion, & I have never been able to make up my mind."

An Irishman, a "grand breeder" of short-horns, declared at lunch that CD’s books had been "a great help to [him] in breeding!"

Summary

Discusses his health following a visit to Dr C[lark?]. Has made an appointment for CD.

Summary

Sends table showing relative force of impact of weight dropped on a plane inclined at different angles.

Summary

Sends CD a draft of a letter to Nature [see 9087], which he thinks expresses CD’s meaning.

Summary

CD thinks GHD’s letter is an excellent clarification [of CD’s conjectural view on the elimination of useless parts in species], but does not want to publish it as his [CD’s] own. Asks GHD to think carefully before he publishes it.