Happy that JH may be leaving Mint and returning to scientific pursuits. HW resumed work on equations in finite differences. Hopes to reconcile discrepancy between JH's and P. S. Laplace's solutions. JH's solution renders only particular, not general, solutions.

Calculating small number of species in aberrant genera of insects and plants.

Joachim Barrande’s "Colonies", Élie de Beaumont’s "lines of Elevation", Forbes’s "Polarity" make CD despair, as these theories lead to conclusions opposite to CD’s from the same classes of facts.

George Bentham’s list of aberrant plant genera. JDH appended the number of species in each genus according to E. G. Steudel’s catalogue [Nomenclator botanicus (1840–1)] and according to JDH and Bentham.

JDH speculates on effect of splitting Australia longitudinally on distribution; it becomes an argument for new creations.