Reliability of barometer and thermometer measurements from balloons. Compares results of several European observers. Suggests new expedition to Teneriffe [Canary Islands].
CD returns a letter from Wollaston.
Although opposed to the Forbesian doctrine [of continental extension] as a general rule, CD would have no objection to its being proved in some cases. Does not think Wollaston has proved it; nor can anyone until more is known about the means of distribution of insects – but the identity of the two faunas is certainly interesting.
His health is very poor and his "everlasting species-Book" quite overwhelms him with work. It is beyond his powers, but he hopes to live to finish it.
No summary available.