Sends a short résumé of his trip on the chance that it will arrive in England earlier than longer letter [158] which he hopes to send by surer means.

He is "incessantly occupied by new and most interesting animals" and thinks he will be able to do some original work in natural history.

Writes with great happiness about the first part of the voyage, after his misery from seasickness passed. He finds himself well prepared, the ship quiet, comfortable, and compact; he has already a "rich harvest" and finds the natural history (especially geology) exceedingly interesting. The tropics are full of great beauty.

CD’s enjoyment of the beauty of the tropics is worth all the misery of seasickness. His mail gave him great pleasure. For two weeks he will visit a large estate in the country, and on return live at Botofogo for some weeks, collecting and learning to know the tropics.

His trip to the interior was full of interest, but exhausting physically. Expects to stay at least a fortnight at Botofogo, because the Beagle returns to Bahia to correct a difference in the longitude measurements. Writes of his companions, of FitzRoy, and of his journal – which he has sent home.

Lists letters received and those sent; comments on family happenings.

The Beagle is back [from Bahia]; two sailors and "little [Charles] Musters" died of fever. In 14 days they sail for Montevideo, then to Rio Negro, then on to where no man is known to have been before.

Writes of voyage and his work in natural history: geology, collecting insects (freshwater beetles and spiders at Botofogo Bay); life at sea, sublime views ashore.

His first letter to JSH since December. Recounts his seasickness, geologising and marine collecting at St Jago [Santiago, Cape Verde Is.]; his first tropical forest. Collecting small insects from the tropics. His Welsh trip with Sedgwick has been extremely valuable.

Summarises experiences since leaving England. "How intimately what may be called the ""moral part"" is connected with the enjoyment of scenery." The loneliness of the voyage.

Sailing next day to Montevideo. He has taken many hitherto undescribed animals. Describes the glories of the Brazilian forest.

Mentions his concern over the Reform Bill.

Regrets leaving the tropics, despite interest in a land where Europeans have never been. They have experienced political turmoil at Montevideo. Natural history going well.

Specimens being sent off. Describes his collection of rocks, plants, and insects. Some particularly interesting specimens.

Brief summary of the voyage so far. His delight in the Brazilian forest; his trip into the interior; the turbulence at Rio; has grown a beard.

During the past two months CD has been lucky with fossil bones, and he is also finding new specimens of living animals.

He describes an ostrich hunt.

Has received several letters from home.

He enjoys Buenos Aires and admires the señoritas. Tierra del Fuego is next.

A French collector [Alcide d’Orbigny] has been at the Rio Negro and will probably have "taken the cream". CD’s luck with fossil bones, among them a large extinct armadillo-like animal. Describes some birds, toads, Crustacea, and other marine specimens. Nearly all plants flowering at Bahia Blanca were collected. Is sending two large casks of fossil bones by packet.

Sketches the Beagle’s travels – Rio de Janeiro, Montevideo, cruise to the south and return – and what the future holds. Writes with nostalgia of England and says he sees no end to the voyage.

He enjoys and has been lucky principally in geology and among pelagic animals; has found remains of large extinct animals.