Describes exactly the route JH took to get to the point where he made his drawings of the earth pyramids at Botzen.

Comments on some of CL's writings; further argues that a canal at Suez and/or Darien would have a major effect on European climate due to the effect of ocean currents coming through such canals.

Some minor suggestions regarding CL's proofs [see CL's 1866-10-19].

Appreciates the receipt of volume one of the tenth edition of CL's Principles of Geology.

Sends a paper, which may help to clarify the effect of the Sahara Desert on certain European winds.

On the temperatures of water in the oceans, and the freezing temperature of sea water.

No summary available.

Sending this note to inform JH that he began his own serpentine paper on Friday and next Friday intends to read JH's paper on Predazzo. Would like to go over the paper with JH beforehand. Intends to publish his own paper in Brewster's Journal. Can JH meet CL here Wednesday morning?

Believes that JH is acquainted with R. I. Murchison, who is to accompany CL to see the works of M. I./I. K. Brunel's Thames tunnel, after they have gone through JH's paper. Would JH like to accompany them?

Arrived here yesterday with the Murchisons and starts tomorrow for the Vicentini. Would welcome JH's advice on what to see and read when in Sicily.

Hears that JH expressed to William Whewell great pleasure in parts of CL's book. Has been altered and improved since the 1st edition. When in Copenhagen last year [H. C.] Oersted was reading JH's paper on double stars. Murray has sold 1750 copies of CL's book.

Charles Lyell wrote letter to JH recently. Now encloses with it letters of introduction to persons in Rio and abstract of paper by Charles Babbage. [Henry] Brougham's attacks on Thomas Young.

Preparing fifth edition of Principles of Geology, using JH's facts about boiling seeds. Mathematical error in CL's climate theory. CL's first speech as president of Geological Society. Criticizes R.S.L. JH's volcanic theory was too complex; will incorporate it into later editions. Benefits to science of Charles Babbage's social parties. Latest publications in geology. P.S. Glad to learn that JH thinks origin of new species may occur through intermediate causes; Germans criticized this. CL chooses not to engage in controversies. Speculates on successive extinction of species. Notes on African hot springs.

Has been requested by Gideon Mantell to write JH a letter of introduction for a Lieut. H. I. Thomas, a friend of Davies Gilbert. Thomas wishes to be the bearer of any letter or parcel CL may have. Believes that a copy of the President's speech he sent may be lost in the post. Thinks that JH's theory of subterranean isothermal lines interesting. Dined with the Somervilles last Sunday.

Charles Babbage will publish JH's volcanic theory in Ninth Bridgewater Treatise, together with JH's letter to R. I. Murchison. William Whewell read both at Geological Society. Babbage wants to compare JH's theory with passage from Bishop [Samuel] Butler. Whewell's notion of new species. Charles Darwin's new theory of coral islands is forcing CL to give up CL's volcanic crater theory. [Letter continues 28 May.] Sends copy of Babbage's Treatise with quotes from JH. News of Charles Wheatstone's submarine telegraph and David Brewster's proof that diamond is of vegetable origin.

When he received JH's request to give a lecture on American geology he did not treat it seriously. Now R. I. Murchison has made a similar request so thinks he could work up a popular lecture on the Mississippi Delta. Will keep off his old ground.

Thanks for the valuable present, which he is reading as fast as possible. Comments on the work in the light of his own researches. Is glad he put in a note about C. R. Darwin.

Came to Florence on account of the sudden death of Mrs. [Joanna B.] Horner. Thanks for the translation of a book of the Iliad, but thinks only Greek scholars should read it. Has some queries regarding the migration of hippopotomi; can JH supply any facts or references?

Has been requested by Edward Twisleton of the Public Schools Commission to give evidence in favor of introducing the teaching of the elements of science in schools. Would like to know JH's opinion, and also if he is willing to give evidence.

Origin of siliceous minerals sent by JH. Planning tenth edition of Principles of Geology. Convinced that changes in position of land and sea were principal causes of climate changes. Questions [James] Croll's theory of astronomical influences on climate, based on data from U. J. J. Le Verrier. Compares earth-pillars in Rhone valley with those in Tyrol. Wants tenth edition to include woodcut of JH's [1821?] drawings of earth-pillars.