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.

Regarding the affair of Dr. Andrew Smith, who has done good work with an expedition. Thinks it desirable that Smith should be given leave of absence to return to England and write up the expedition.

JH has no need to apologize for bringing before him the case of Dr. Andrew Smith. Heard the news from Dr. John Murray. Will press Smith's request in the appropriate quarter. JH should address his request to Benjamin D'Urban.

Many thanks for the seeds. Will record in the minutes the source of the plants. Breakfast will await JH's arrival. Has been comet hunting every morning to no purpose.

As the error of the African chronometer is only 0m 1.1s fast on Cape mean time, he sends it. James Adamson is with TM or TM would avail himself of JH's invitation. The comet was superb last night. A most interesting phenomenon last night was the motion of the comet's nucleus over a small star.

Gives measurements for the nucleus noted in his letter of 26 Jan. Regrets the delay of the last list of stars. Wind was tremendous last evening. Feared for the safety of the dome. Finds there is a quantity of sand in the box chronometer.

Many thanks for the portrait; it shall soon have a resting place. Will not rest until the comet observations are en route to England. T. G. Taylor does not observe himself. There was a beautiful occultation of three stars last night.

Would welcome changes in the nomenclature of the constellations. Hesitates to compute the observations of John Burrow.

Dr. Andrew Smith called yesterday. Has succeeded in establishing a postal system for the Observatory. The comet was faint last evening. Had a parcel from the Admiralty but no word about the tide gauge. Sends the Simon's Bay observations, also the P. P. Barraud chronometer, which loses time at a great rate.

Believes his acquaintance with the comet is drawing to a close. A 30" transit was placed in the meridian last night. Returns the Pulkova observations. Believes the bad weather may have upset Lady Herschel's journey.

Believes the wires are 0.2" thicker than the old ones. Dust has settled on the parallel wires of the telescope. Advises how adjustment may be made to JH's micrometer for parallelism.

Was necessary to reduce the whole of the sixth months' observations. More scanty than he desired but much of his time was taken up observing the comet stars. Is now busy with the comet stars. Does not send the precession as JH has them in his list.

Sends the list of comet stars; the constants will be computed at the Observatory and will send a copy. Encloses letters from [W. H.] Smyth and others. Lead is being removed from the roof of the lantern.

Intends to dispatch the packet to the Admiralty in a few days and await Francis Beaufort's instructions regarding the printing. TM's son would be grateful for the Herschels' gift could he express thanks himself. Would like the loan of the actinometer. Sends the dome observations.

Returns copies of the Comet observations and the formula for parallax and refraction. The 21st was a busy circle day. The mural circle is in better trim than ever. Sends a chronometer.

Barometer is swinging without encountering any accident. Believes there is to be a new clergyman at Rondebosch, the old Observatory housekeeper, John Fry, shortly to land from England. Hopes he is more adept at sermons than he was arranging the catalogue of instruments.

Encloses the sweeps for June 1836, which JH lent him. Not a word about printing, or the Tide gauge in the letters he received. Will forward the letters from G. B. Airy and Francis Baily. Thomas Henderson is about to be married. Cannot procure white deal without knots. Will try an old mast.

Reports on JH's actinometer observations. Explains why he subscribed to 'Col. [Harry] Smith's piece of plate.'

Cornerstone and tree answer admirably. Gives the points in the present triangulation. Lieut. John Williams of the Engineers has promised assistance. There is a French frigate in the harbor, which he intends to visit.

Definition at the Observatory last night was abominable; therefore no comparisons can be made between the stations. Much obliged for the details of the actinometer. Will call on JH later.