Summary

Lyell wants to see JDH’s last letter [the part on glacial periods]. Lyell full of concern about astronomical causes of heat and cold on the globe.

Encloses letter from John Scott.

Summary

Reviewing C. V. Naudin’s article ["Nouvelles recherches sur l’hybridité dans les végétaux", Ann. Sci. Nat. (Bot.) 4th ser. 19 (1863): 180–203] for Popular Science Review [5 (1866): 304–13]. Requests references.

Proposes to visit Down on Easter weekend.

Summary

Thanks for explanation on relative fertility of homostyled and heterostyled crosses in Primula. Sends an intermediate form with small stamens, but stigma only slightly above stamens.

Election as Botanical Lecturer at St Bartholomew’s Hospital.

Summary

Asks botanical readers to inform him "whether in those monoecious or dioecious plants, in which the flowers are widely different, it has ever been observed that half the flower, or only a segment of it, has been of one sex and the other half or segment of the opposite sex, in the same manner as so frequently occurs with insects?"

Summary

Thanks for "Climbing plants" and other papers [as requested in 5316].

Sends specimens of a variety of Primula not mentioned by CD [in Primula paper, Collected papers 2: 45–63?].

Summary

Hildebrand’s paper on trimorphism in Oxalis ["Über den Trimorphismus in der Gattung Oxalis", Monatsber. K. Preuss. Akad. Wiss. Berlin (1866): 352–74].

Problems of explaining brightly coloured, attractive seeds.

Haeckel has visited Down.

FM’s climbing plants paper is printed [J. Proc. Linn. Soc. Lond. (Bot.) 9 (1867): 344–9].

Summary

Fertilisation in orchids: Friedrich Hildebrand’s paper.

Self-sterility.

Climbing plants.

Agassiz’s attempts to eliminate all Darwinian views.

Summary

Has forwarded FH’s paper on Fumariaceae to horticultural congress. Comments on its findings.

Discusses forms of Oxalis.

Summary

Thanks CD for supporting his application to the Royal Society.

Summary

Pleased by JDH’s success. JDH gives argument for occasional transport with perfect fairness.

W. R. Grove’s address [see 5201] good, but is disappointed that species part was so general.

Summary

Orchids.

Lyell has written to JDH about coal-plants of Melville Island.

Has glanced at first edition of Principles and has no doubt that Lyell meant the whole globe was cooler when land was massed at poles. JDH doubts this.

Summary

Lyell’s volume [Principles, 10th ed.] received.

"We must now keep him straight anent origin and development."

Some of Spencer’s new part is interesting but much is dull and ponderous.

Huxley’s Elementary physiology [1866].

Has finished his New Zealand manual [Handbook of New Zealand flora (1864–7)]. New Zealand flora [and past geological conditions] suggest islands were once connected.

Speculates on the total amount of living organised matter on the globe, and whether it varies.

Balfour Stewart on sunspots.

Summary

Discussion of Mrs Agassiz’s letter [to Mary Lyell, forwarded to CD] regarding S. American glacial action,

with comments on Bunbury’s letter on temperate plants.

Refers to opinions of Agassiz, David Forbes, Hooker, and CD on glacial period and glaciers.

Wishes he had published a long chapter on glacial period [Natural selection, pp. 535–66] written ten years ago.

Tells of death of his sister, Catherine, and other family matters.

Summary

Had Busks and Lyells to dinner.

Examines and criticises evidence for CD’s hypothesis that the glacial period was not one of universal cold. Physicists deny its possibility.

Summary

Feels sure that at times the globe must have been superficially cooler. Believes CD will turn out right with regard to migration across the equator via mountain chains, while the tropical heat of certain lowlands was retained.

Summary

Comments on cool-period MS. Still believes geographical changes principal cause of former changes of climate.