Is obliged for GM's letter and for the trouble he has taken over JH's paper on musical scales. Object in writing this paper was to clear the ground as it were. Elucidates some of the points in his own paper and comments on parts of GM's paper.

Regarding the inventor of the compensation bars. Would not attribute their invention to Thomas Drummond in the light of J. E. Portlock's evidence. Thanks for the paper on ancient Greek kinship.

Regrets delay in answering letter but has been away from Collingwood and letter was not forwarded. Is unwilling to write article for another journal as he is already producing articles for an editor. Would editor of Good Words be interested in printing three lectures he gave at Hawkhurst on volcanoes, comets, and the sun? Could work this up for an article.

Will not be able to produce his article in time for the January issue, but could write a much better article on meteorology if given longer, till July.

Does not think Mr. Thornton's pamphlets solve the problem of squaring the circle as the circle is 3/4 of the circumscribed square. Comments further on these theories.

Is fully satisfied with the objections in WM's letter regarding the individual records of barometric pressure. Gives advice on how the records should be shown.

Is honored by DM's letter and proposal to dedicate his book [Traité général de photographie] to JH. Points out some errors of attribution he would like incorporated if not too late. Pass on his good wishes to J. A. F. Plateau.

Thanks for the receipt of the Radcliffe catalogue of stars, but wishes observations had been equatorial rather than circumpolar.

Suggests an observational program for RM's newly purchased transit circle [see RM's 1861-10-21].

Declines the opportunity of writing an article on the Great Pyramid for Good Words, especially as he disagrees significantly with Charles Piazzi Smyth's views. Might write an article on another subject.

Thanks RM for the double star observations he has sent.

Sends RM a copy of Angelo Secchi's double star observations pointing to a very large number of calculation errors.

Seems to JH to be some systematic error in some of RM's observations; JH includes examples.

Thanks RM for his offer [see RM's 1869-1-26]; wishes astronomers would develop an accepted system of indicating the quality of observations.

Cannot supply testimonial as he has no knowledge of any other of JM's writings, nor does he know him personally.

Health makes it impossible for JH to travel to Glasgow.

Agrees that a large part of the hills and valleys are due to tidal action. Comments further on this, especially relating to parts of France. The Hawkhurst lectures have ceased and are not likely to be resumed.

Reasons why he is unable to sign the Memorial to the bishops regarding their attitude to Essays and Reviews.

Requesting information as to where he can find details of the principle that regulates the application of the Greek accents.

Outlines the early life of his father, Sir William Herschel, and shows that the cutting received from the Stroud Journal was inaccurate. [Marked 'not sent.']