Returns JFR’s copies of Transactions [Agric. & Hortic. Soc. India]. Has not found quite as much as he thought he might on varieties of Indian domestic animals and plants; "the attempts at introduction have been too recent for the effects, if any, of climate to have been developed". Is impressed by the work of the English in India.

Questions Mrs W on difference in flight capacity of male and female silkworm moths and asks her for results of experiments he suggested she do with silkworms to determine hereditariness of dark "eyebrows". [See Variation 1: 302.]

Discusses David Milne’s Glen Roy paper ["On the parallel roads of Lochaber", Trans. R. Soc. Edinburgh 16 (1849): 395–418]. Rejects Milne’s theory that outlet of Glen Roy is blocked by detritus. Impressed by Milne’s discovery of an outlet at the level of the second shelf. Believes this strengthens theory that lakes were formed by glacier blocking Glen Roy. Offers arguments against glacier theory.

Agrees to lease land to Mr Mason. Discusses arrangements for bank draft.

Comments on David Milne’s paper ["On the parallel roads of Lochaber" (1847), Trans. R. Soc. Edinburgh 16 (1849): 395–418]. CD still believes in marine origin. Rejects barrier of detritus at mouth of Glen Roy. If roads were formed by lake, it must have been ice-lake.

Comments on evidence of glaciers and icebergs in North Wales. Thinks pass caused by tidal channel, not river. Suggests that RC make altitude measurements at various points.

David Milne’s attack on his Glen Roy paper ["On the parallel roads of Lochaber", (1847) Trans. R. Soc. Edinburgh 16 (1849): 395–418] made CD horribly sick.

Wants Thomas Thomson to establish geographical range of erratic boulders in India.

Comments on paper by DM ["On the parallel roads of Lochaber", (1847) Trans. R. Soc. Edinburgh 16 (1849): 395–418]. "I am not in the least convinced about the Barriers … [but] I am very much staggered in favour of the ice-lake theory of Agassiz & [William] Buckland." Will "send a letter to the Scotsman, in which I give briefly my present impression".

Cites facts mentioned in South America possibly of use to DM.

Comments on article by David Milne ["On the parallel roads of Lochaber" (1847), Trans. R. Soc. Edinburgh 16 (1849): 395–418]. Refers to his paper on Glen Roy [Collected papers 1: 87–137]. Comments on Louis Agassiz’s article ["The glacial theory and its recent progress", Edinburgh New Philos. J. 33 (1842): 217–83]. Cites his own observations on glaciers in N. Wales. Discusses possibility of ice barrier creating lake. Notes objections to theory of an ice barrier. Defends his own theory that the roads are sea-beaches. Suggests questions for further investigation.