Commends ARW’s papers on parrots

and on the theory of geographical distribution [see 4750].

Wild pigs in Aru Islands must have been introduced and later ran wild. Does ARW have an opinion on the subject?

Orders that one of CD’s Porto Santo rabbits be killed and sent to him.

Asks whether ADB has got young from mating these with females of other breeds.

Encloses two certificates and hopes that he will give the candidates his support. Has just received a letter from Angelo Secchi on the Herschelian prism.

Thanks for kind letter. Pamphlets should have reached him by now. Discourses on the effects of cold and heat on the spinal cord.

Origin of siliceous minerals sent by JH. Planning tenth edition of Principles of Geology. Convinced that changes in position of land and sea were principal causes of climate changes. Questions [James] Croll's theory of astronomical influences on climate, based on data from U. J. J. Le Verrier. Compares earth-pillars in Rhone valley with those in Tyrol. Wants tenth edition to include woodcut of JH's [1821?] drawings of earth-pillars.

Returns the certificates duly signed and also Angelo Secchi's letter, which he was pleased to see. Elaborates on the possible causes of James Nasmyth's 'willow leaves.'

Sends papers with comments. Convinced that the Aru pig is a species peculiar to New Guinea fauna, not a domestic animal that ran wild.

Admires CD’s paper ["Three forms of Lythrum", Collected papers 2: 106–31].

[Outline sketches of pollen from short-styled yellow primrose and from long-styled yellow and red primroses.]

Thanks for 'valuable addition' to HU's book.

JDH writes that he has no fruit of Fothergilla & asks Asa Gray whether it's Endocarp separates as coccis. Mentions Parry's seeds. Has been busy with GENERA PLANTARUM, describes the work he has been doing on various orders, genera and tribes for the book incl.: calyciflorous orders, Cucurbitaceae with input from Charles Victor Naudin, Melastomaceae, Abobreae, Elatereae, Loaseae, Passifloreae, Papayaceae, Modecca, Acharia, Begonias, Cartesia[?], Hamamelideae, Saxifrageae, Bruniaceae, Grubbia, Santalaceae & Corneae. [Letter incomplete, it bears no valediction or signature but is written in the hand of Sir Joseph Dalton Hooker].

Exchange of photographs.

Aru pigs present perplexing case, whether wild or domesticated.

Hugh Falconer’s death great loss to science.

His own health has been especially bad this last week.

Notifying him of a forthcoming meeting of the Lunar Committee of the B.A.A.S. Hopes he will attend.

Falconer’s illness and suffering. His great ability and knowledge.

CD’s paper ["Climbing plants"] went extremely well [at Linnean Society]. M. T. Masters and Bentham commented.

Is glad MTM is going to experiment on Passiflora.

Is grieved to hear that John Scott has been inaccurate but cannot think he recorded, in his paper, experiments that he never made [see 4485].

Comments on the revolution of the apsides of the earth's orbit and its effect on glacier theory; further comments on the earth pyramids of Botzen [see CL's 1865-1-31], and associated phenomena.

Having read JH's paper in Good Words on the weather he commenced a series of observations of the state of the sky during three days of each lunation. Will be pleased to continue sending his observations if JH is willing to accept them.

He has finished MEW’s work on hybrid willows [Die Bastardbefruchtung im Planzenreich (1865)] and sends his thanks. The extreme frequency of hybrid willows is new to CD, and he finds the explanation of their numbers in certain locations ingenious.

Comments on the criticism of Gärtner’s view of reversion

and the differences between MEW and Naudin.

CD now has doubts regarding his own view that hybrids are sterile from not being perfectly accommodated to their conditions of life.

Sending his paper on the causes of change of climate, and would be glad of JH's comments and opinion on its worth.

PS's results on light and magnitude of stars agree with JH's results at the Cape. Comments on PS's research on light of planets.