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

Will do all in his power to ensure that MM receives copies of the publications relating to the Fixed Observatories. Does not think MM could have seen a copy of JH's paper on photographic action when he wrote the notice in Annales de chimie. Comments on this paper and more recent experiments in this field.

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.

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.'

Requests autographed copy of WH's sister's poems, wanting to send them to an acquaintance who translated some of JH's work. Expresses a theory about cause and effect. Mentions minutes of Royal Irish Academy, a reform of the constellations, and WH's three axes of the universe.

Reports the birth of Amelia Herschel, JH's eighth child. Forwarding to CH an article describing the telescope of William Parsons.

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.

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

Has received material sent by GA [see GA's 1841-3-20]; comments on the report and JH's unavailability for meetings of the Standards Commission in the near future.

Congratulates WT on the calotype invention and the patent. Responds at some length to WT's concerns about the infinity of the universe. In postscript, provides a 4-page dialogue on the subject.

On mode of conveyance of WH's sister's verses and the autographs for JH's acquaintance.

A further two dialogues elaborating on JH's earlier arguments [see JH's 1841-3-18] on the infinity/finitude of the universe.

Has not unpacked William Herschel's letters that JH secured from the R.S.L.

Sends letter on the subject of the star maps.

Regarding the payment of John Arrowsmith's bill for the printing of the star maps, which seems excessive in relation to the low standard achieved. Would like FB's comments.

Doubts that isomerism of all elements can be verified experimentally, but notes a number of groups with similar atomic weights that might well fit. Further on vegetable colors in photography. Refers to enclosure of a further dialogue on infinity.

Further about the map printing problem [see FB's 1841-4-6].

Would like some dry prints of the star map, if no further expense is involved. Is sorry that he has caused him all the bother.

Asks WW to be godfather to JH's new daughter, Amelia. In reviewing WW's [Philosophy of the Inductive Sciences] has found many of JH's views changing, but cannot accept his dear friend's a prioristic approach.

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