Regarding the advisability of purchasing a patent in the photographic process.

Complains further about French specific gravity designation [see JH's 1841-8-14 or earlier], and describes observing colored fringes on the edge of clouds.

Thanks AD for his theorems; comments on the value of such abstract speculations.

Writes to announce the birth of daughter Amelia, and to assure RA that both JH's wife, Margaret, and new daughter are doing well.

Progress on barometer curves. Invites WB to send report, to be read at B.A.A.S. meeting in July.

Sends missing barometer observations from Montreal, Flushing, and Albany. B.A.A.S meeting postponed.

Received WB's report on barometer observations. Admires perfect finish of work.

Fully examined WB's report [on barometer observations]. Agrees to combine British and Continental observations. Curves clearly show atmospheric processes. Likes WB's suggestion of tracing atmospheric wave beyond 24 hours; will propose this to B.A.A.S. Irregularity of Asiatic and South African data.

Cambridge barometer observations. Postponed WB's detailed report until 1842 B.A.A.S. meeting. This year JH will report generally on atmospheric curves and WB's notes. Hopes WB will attend to give explanations.

A testimonial on behalf of Olinthus Gilbert Gregory, deceased, to assist Mrs. Gregory in obtaining a Civil List pension.

Heard of WB's bout with typhus. Interest in atmospheric waves should ensure publication of WB's article in Athenaeum. Will write editor on WB's behalf. Awaits completion of atmospheric curves for B.A.A.S. Congratulations on recently acquired office.

It will be difficult for JH to get away to Collingwood as planned as discussions [?] are slow; some family news.

Explains 'discordances' as contraction of damp paper. Use 'Engraved Squares' to avoid this error. Possible error in barometer observations from Montreal. Diurnal 'undulation' appearing in data. American observations arrived, may fill 'missing intervals.' Keep record of expenses incurred. Postscript on color variation in stars.

Received WB's packet. Will send sheets tomorrow. Needs all 'Curves and data' before end of March for final report to B.A.A.S. JH's nerves 'shattered with night work.'

[WB's] sheets [of barometer observations] are well done. Sends European latitudes and longitudes. Will send 'Engraved Squares' soon. Notes errors in observations.

Compliments MH on her poetry; JH is trying to clarify when various friends are to visit Collingwood.

A portable magnetometer purchased by the B.A.A.S. is now available as a loan for use in magnetic survey of British Guyana.

[Composite letter written by JH, Margaret Herschel, and their daughter Caroline.] JH sends thanks to JC for gifts for the children and also sends JC some specimens of photography.

Notes interest expressed by Macedonio Melloni in meteorological observations. Urges that R.S.L. Council give its attention to the mass of meteorological observations that have accumulated.

Praises WT for invention of 'Kalotype' process; predicts it will be called 'Talbotype.' Notes excellence for photography of the weather during past year. Mentions possibility of cases of excessively rapid photographic change.