Raises with GA the likelihood of an error in a date of a transit of Mercury in a paper by F. A. Winnecke.

Replies to JH about the date of the transit of Mercury [see JH's 1864-1-[26]].

Discusses aspects of JT's new book [The Great Pyramid], especially its front matter.

Asks JH for information on the Beaufoy Clock owned by R.A.S., which is now missing. Requests JH to read R.A.S. Annual Report.

Thanks JH for solar observations. Discusses 'willow leaves' observations made at Greenwich Observatory after following JH's suggestions for solar eyepiece.

Regarding Thomas Spring-Rice (1st Baron Monteagle), the Treasury and the Commission on Weights and Measures.

Thanks for FA's star atlas series, one of which is a duplicate; reports apparent variation of a nebula.

Mistaken about seeming duplicate [see JH's 1864-1-28].

Has been asked to reweigh the damaged Parliamentary standard pound weight; thinks that W. H. Miller would be a more suitable person to do the job.

Correspondence relating to the fall of a meteorite in South Africa on 13 Oct. 1838, and the provision of samples from Thomas Maclear by way of JH. [Letter illegible in parts.]

At request of William Crookes, JS [editor of new Quarterly Journal of Science] invites JH to submit original article on sunspots. Promises liberal honorarium . See article on sunspots by C. A. F. Peters in Zeitschrift für populäre Mittheilungen aus dem Gebiete der Astronomie und verwandter Wissenchaften.

Encloses copy of C. A. F. Peters's article in Zeitschrift für populäre Mittheilungen aus dem Gebiete der Astronomie und verwandter Wissenchaften. Please submit JH's article on sunspots by February. Audience of Quarterly Journal of Science are 'intelligent students of other branches and intelligent laymen.'

Needs Zeitschrift volume; then JH may have it back [see JS's 1864-1-15]. JH's article should be 10-12 pages. Compliments JH's writings as popular without being 'popularising.'

RC's book [Observations of the Spots on the Sun] is done. First copy, exhibited at R.A.S. last week, was well reported in R.A.S.M.N. Will send copy to JH.

Formulas for determining rotation rates of sunspots relative to latitude on solar surface. Believes equatorial parts of photosphere are dragged faster than others. Speculates on rotation rate of solid body below (if such exists).

Gratitude for JH's gift of Caroline Herschel's autograph manuscripts to R.A.S.

Received JH's two letters acknowledging receipt of 'Volume of Tables of Heights' of the Great Trigonometrical Survey of India. Hopes to visit JH and discuss phenomenon of terrestrial refraction. Received valuable assistance on tables from JH's son John.

Asks that consideration be given to 'wishes of the Cadet' in selecting a regiment for him.

In response to the gift of a book, JH comments on the philosophy of knowledge, and goes on to say that JH agrees with [John Stuart ?] Mill's rejection of the syllogism as a means of argument. In the postscript, JH comments on the nature of heat.

About geodesic books and JH's encouragement to John to keep asking questions; indeed JH is almost insistent on son John's writing to JH with questions, book needs, and confidences. JH also talks about finding the arithmetical mean of a number of observations. [Also included is the 1st page of a letter to John from one of his sisters.]