A story about Voltaire; arrangements to visit AD.

A letter of great sadness: someone is at death's door; not much hope is held out. [This letter may refer to the imminent death of daughter Margaret Louisa, because of its reference to poor Reginald, which was the name of MLH's husband].

Mostly taken up with JH advising AH about changing his course of studies at Cambridge, together with some family news from home.

[Responding to HS's 1859-12-31,] JH presents additional problems in the nebular hypothesis, critiques in detail HS's views of the distribution of cometary orbits, and argues against HS's theory of sunspot formation.

Please send copies for distribution to JH's friends of JH's paper ['On a New Projection of the Sphere'].

Thanks TS for TS's publication on lighthouse illumination; adds some of JH's own ideas on the subject.

Sends JH's 'On Atoms' to WP.

Comments extensively on the calculation, and elimination, of error in geodesic measurements; JH concludes with a few family news items.

Begins with a discussion of the probability of error in a series of measurements and comments on astronomical observations including the observation of a comet.

Discusses the possibility of stereoscopic photography of action scenes. Also speculates about color photography.

[It having been asserted in the Times that the Russians have not communicated about the climate at Pekin], JH notes that in fact wonderfully detailed meteorological observations for Pekin from 1850 to 1855 have been widely distributed by the Russians.

Expresses his views on how the British should select their standard of length. Also discusses John Taylor's views of the Great Pyramid.

[Following up on JH's 1860-4-23,] notes another numerical relationship between the dimensions of the Great Pyramid and those of the earth.

[Writing under the pseudonym 'Redde Suum Cuique'], JH notes that a recently published process for recovering silver from old plate was in fact anticipated by James Keir in a 1790 R.S.P.T. paper. Attacks a recent misuse of the word 'actinometer.'

Comments on the behavior of Sirius with its companion, and on the likelihood of the existence of the inter-Mercurial planet.

Asks for meteorological data that RF may have collected.

Asks for information about wrecks at sea and lives lost.

Thanks for a number of RF's writings; asks for more rainfall data to try to establish a relationship between rainfall and the solar cycle.

Thanks for all the material received; comments on some of RF's meteorological ideas.

Comments on RF's writing on drifting ice; comments extensively on RF's ideas about air circulation.