Asks JP to remember him if anything occurs to him "in regard to inheritance at corresponding or rather earlier ages". Sends JP a few examples for his "Chronometry of life". CD is sure he often met with striking facts but he disregarded them. "Deviations alone would have struck me."

Effects of different climates on breeding periods.

If only one observer is assigned to Peking, observations could not be conducted. Describes staff and expenses at other magnetic observatories. Edward Sabine's plan to adapt all instruments to photographic self-registering instruments.