Is unable to come to London for the Standards Commission meeting and thus will also not be able to come to the dinner party. Encloses some recent photographs.

Thanks RH for his 'extensive and instructive view on the present state of photography.' Found many interesting results in experimenting with vegetable substances. Surprised by RH's discovery that bi-chromate of potash is a photographic substance; JH nearly achieved this result.

Does not expect to come to the meeting [see GA's 1841-5-18], but sends comments on altered sections of the draft report.

JDH informs his father, William Jackson Hooker, that [Ronald Campbell] Gunn has left Hobart [Tasmania, Australia]. It is winter & the only plants are Cryptogamia, the summer was hot; shrivelling vegetation & causing fires that burnt the woods, seeds have been dispersed & some plants are flowering for a second time e.g. Epacris impressa & some Acacia. Recounts a trip up D'Entrecasteaux Channell on the River Derwent to the Huon River with Captain Briggs, to see Huon Pines. The D'Entrecasteaux Channell reminded JDH of the Kyles of Bute, but surrounded by gum trees, Asters & Leucopogon richei & long cutting grass. The plants on the Huon are more alpine with tropical vegetation in deep gullies. He describes some of the ferns, which incl: Allantodia australis, Polypodium vespertilionis, Pittosporum bicolor, Anopterus glandulosus & Sassafras. Also describes some beautiful, very large tree ferns giving dimensions & describing the character of their growth in the valleys. Tree ferns are covered with Psilotum triquetrum, Asplenium laxum, Polypodium grammitidis & Grammitis australis. Mosses in the valleys abound: Hookeria pennata, H. quadrifaria, Hypnum cochleariformis & a new Anomodon. Mentions an island in the mouth of the Huon made completely of fossil shells in sandstone, & on which some Asplenium species grow. Letter also includes a coloured illustration of a new species of Hookeria. The Hookeria was found growing on Dicksonia arborea on the Banks of the Huon River opposite Port Cygnet.