Sends a sample picture fixed by use of iodine [potash].

More photography comments. Problems with use of hyposulfite fixer. Superiority of English over Daguerreotype in being able to make copies.

Confused by an 'unfixed' photo from JH in which the image shows different effects from different colors of the spectrum. Also other comments on photography.

Sends JH a positive copy and a transparency. Remarks on JH's use of muriate of lead and asks JH to explain chemistry of it.

Advises JH not to publish any new processes in photography as there are patent problems. Comments on the Daguerreotype, and on the difficulty of preserving images in some circumstances.

Sends some samples of photography made with a solar microscope, and comments briefly on the Daguerreotype.

Cannot accept JH's invitation to dinner. HL and Edward Sabine depart tomorrow for [Batind?].

[Letter appears to be a response to some criticisms by JH of BV's paper on Encke's comet submitted to the R.A.S.] Deals with the density of the comet's nebulosity and with the effect of the comet's approach to perihelion, gives estimates of the comet's magnitude, and comments on the behavior of gases.

Returns reports on Cape Observatory and reform of star nomenclature. FB was not included in committee to report reduction of stars in N. L. Lacaille's Coelum australe stelliferum, but sends FB's own report on it, which JH may send in.

Read JH's letter to [Felix] Booth regarding magnetic observations in Europe. Describes WB's building and instruments for magnetic observations. Wants information about German observations.

Will visit C. R. Fox at Ordnance to speed up official letter to Treasury requesting additional officer on magnetic expeditions. Will inform JH when letter reaches [S. H.] Christie [at Royal Military Academy, Woolwich].

Sent wrong paper to JH in Nov. 1838. Now sends complete meteorological journal from Mr. Lees, HD's stepson. [JH annotation: Answered 18 Jan. 1839.]

Asks JH to comment on draft of letter from H.E.I.C. court of directors to Marquis of Northampton in response to R.S.L.'s request for support of magnetic survey.

In R.S.L.'s request to H.E.I.C. court of directors for support for magnetic survey in India, Lord Northampton omitted to stress need for training TJ and other officers in use of special instruments.

Attended [French] Institute and heard D. F. J. Arago read account of L. J. M. Daguerre's process, which is very different from those of JH and W. H. F. Talbot. Has not yet visited Francesco Carlini to give him JH's letter. Introduces J. T. Boileau, who will participate in magnetic survey.

J. T. Boileau and L. E. O. Ludlow were appointed by H.E.I.C. to direct Indian observatories. R.S.L. is concerned that it has no choice in selecting directors. Instruments for H.E.I.C. observatories. Should JL request additional staff for all 16 observatories, or only for nine permanent ones?

[Marked 'Private.'] Encloses letter from Alexander von Humboldt containing suggestions to R.S.L. regarding J. C. Ross's expedition.

Lord Melbourne [William Lamb] will meet next Wednesday at 4 o'clock with deputation [from R.S.L. regarding Antarctic expedition]. Duke of Sussex is willing to meet with R.S.L. council next Saturday at SC's house.

Lord Melbourne [William Lamb] changed meeting [with R.S.L. deputation] to 4:30.

The report by G. B. Airy, Thomas Henderson, and JH on N. L. Lacaille's stars will be brought forth at the next meeting of the B.A.A.S. JP requests a copy in advance of the meeting.