Board of Longitude will meet at TY's home on Saturday.

Repeat computation for Jupiter's satellite IV [see TY's 1824-4]. Explains W. H. Wollaston's 'blue bow.' See figure 422 of TY's [Lectures on Natural Philosophy].

As R.S.L. vice president, JH should reconsider his report favoring Eilhard Mitscherlich over W. H. Wollaston. This may be last opportunity to pay Wollaston a 'just compliment.' Agrees with JH that much in R.S.L. 'nicknamed science [is] sleight of hand,' and that 'great injustice is done to men of science.' But TY expects a short life and tries not to be concerned about approval of others.

TY would rather have JH's labor made useful another year. W. H. Wollaston does not want [Royal] medal, but medal wants Wollaston. One council member felt that TY's remarks offended JH. Assures JH it was not intended.

Thanks TY for books and for taking charge of [G. A. A.] Plana's plates. JH mentioned Eilhard Mitscherlich only when no other proposals came forth. Matter was left hanging. Assures TY that JH was not offended [see TY's 1824-11-21, i.e., #1075]. Regrets 'dilapidated state of scientific matters' in R.S.L.

Math is flimsy in John Dalton's theory of vapor dispersion, but physical grounds are firm. Sends copy of TY's volume on sound. Modules of elasticity and tension are analogies to explain TY's doctrine. Presently studying modules of elasticity that do not apply to chimney pipes investigated by Daniel Bernoulli and J. H. Lambert.

Edward Sabine declares that R.S.L. is hostile to ES's interests. If ES makes future claim for compensation, JH wants TY's opinion in writing. Need to order four night glasses for Fairlight Station. Encloses letter from [Richard] Copeland.

Ask Charles Babbage to send tables of logarithms to TY, who will compare them to [Brook] Taylor's. Bets that five errors will be found. Did JH order mountain barometer from [J. F.] Newman? Will inquire about [W. E.] Parry's instruments. Admiralty, not us, should order sextants.

Questions JH's conclusion that Board of Longitude has power to interfere in Admiralty operations. Disagrees that Nautical Almanac errors are serious. Compares them to tables of Charles Hutton, F. X. von Zach, and H. C. Schumacher. When will TY receive Charles Babbage's table?

Encloses note from Sir John Barrow refusing scientific instruments and objecting to using barometers. Supplying cameras and sextants to Admiralty's marine survey is not interference by Board of Longitude. Sent JH's expenses to Edward Sabine; has no further word on subject. Encloses Mr. Stewart's note about damages at Wrotham.

[Board of Longitude] must answer to Parliament, not to public opinion. Do not contest the system. Order pocket sextants; they and barometer will be sent to Captain [Richard] Copeland. Knows how JH feels about expenses sent to Edward Sabine, but please write receipt and send it to TY within week. Will write directly to Charles Babbage for tables.

Suggests change in JH's table of refractions. Possible error in John Pond's reductions [illustration].

'Our volume is nearly ready.' Problem dating vernal equinoxes before Christ's birth.

T. M. Brisbane is in town. Can JH meet him? JH's computations of definite integrals are simpler, more direct than P. S. Laplace's and more conclusive than Leonhard Euler's. Comments on W. H. F. Talbot's letters demonstrating Josef Fraunhofer's theorem.

Board of Longitude will accomplish nothing by meeting before T. M. Brisbane comes to town, but TY suggests informal discussion, either at TY's or Henry Kater's.

Henry Kater not well [enough to travel] and requests committee meet at Kater's house. TY urges JH to verify W. H. Wollaston's measurement of refraction before republishing JH's essay. Diagrams Christiaan Huygens's principle of refraction. TY is making forms of aplanatic lenses.

Hopes JH will stay for Sunday dinner at TY's before JH visits Dr. Litten. If so, please invite T. M. Brisbane and Francis Baily to join them. Writes formula TY discovered for discontinuous spectra. TY can now communicate with H. W. M. Olbers and T. J. Seebeck via H. C. Schumacher.

Abandons TY's argument on Mr. Roberts's object glass. Asks JH's help in understanding A. J. Fresnel's calculations of diffraction and Josef Fraunhofer's discontinuous functions.

Sudden demolition of Board of Longitude. TY is left as superintendent [of Nautical Almanac]. Notes quality of J. F. Encke's almanac for 1830. Should English compete with German astronomers, or discontinue almanac supplements? TY's paper on 'Astronomical Chronology' in W. T. Brande's [Quarterly Journal of Science and Art] illustrates JH's equatorial time.

Encourages TY to publish 1829 supplement to Nautical Almanac. JH originally proposed supplement to introduce improvements that would bring N. A. to be like Encke's Ephemeris. That is all ended now. English are dropping behind French and Germans in science. JH refuses to accept money from government 'which treats its agents so cavalierly.' Reduction of Parramatta [Australia] observations. Did not see TY's paper in W. T. Brande's [Quarterly Journal of Science and Art], but objects to substitution of true for mean equinox.