Thinks JT's work on polarization will lead to remarkable discovery. Discusses production of rainbow, parallels to Isaac Newton's explanation of black spot on a soap bubble, and problems in JT's undulatory theory explanation of reflection. In JT's experiments, what are nebulous particles produced by light in gas or vapor?

Continues experiments with carbonic acid and electric light [see JT's 1868-11-30], hoping to 'explode' idea that atmosphere's polarization is due to reflection by air particles.

Thanks for paper verifying JH's prediction that explanation of blue sky color carries with it that of polarization of skylight. Involves ultimate link between chemical and analytical dynamics. Notes that 'neutral points' in sky polarization have yet to be explained; offers tentative explanation based on clues in JT's work.

Thanks for paper on comets. Offers questions, problems to be resolved, particularly on termination of comet.

Surprised that JT cannot obtain heat spots [see JT's 1864-11-14]. Describes glasses and lenses used.

Thanks for lectures on heat motion theory and radiation through earth's atmosphere, and for brochure on 'conformation' of the Alps. Asks about upcoming lecture of JH's son [Alexander].

Thanks for and comments on papers on scientific history and molecular physics, particularly on a magnetic experiment and on dynamical efficiency of coal relative to motion theory of light and heat. Comments on nature of heat, 'vis viva.' Deplores laxity with which physicists use and confuse terms 'force,' 'motion,' and 'energy.'

Regrets 'stupidity' of Italian post office, which lost note sent to JH suggesting reprinting of passage from Treatise Astr. of 1833 on operations of sun in second edition of JT's book. Also wants to publish JT's 'extremely philosophical views' on muscle contraction.

Gives account of observations on lunar radiation, including detailed description of experiments.

Thanks for a gift.

Finds JH's approval incredibly gratifying. Thanks for gift of rock salt. Is sending unscientific book; trusts JH's interests are broad enough to appreciate it.

Does not believe surface of moon can radiate cold; perhaps new moon can. Explains this geometrically.

Apologizes for not having seen JH's paper on spectra of colored flames and thus having overlooked JH's prior claims [see JH's 1861-7-21]. Will try to make amends.

Is not 'at liberty' to speak of experiments on change of refrangibility of 'extra-red' rays. Discusses other experiments on extra-red regions, having used various prisms but not obtaining JH's results.

JT does not have 'luxury' of using sunshine; uses electric light. Perhaps this adds to inability to obtain heat spots [see JH's 1864-11-16].

Observations on subjecting carbonic acid to concentrated beam of an electric lamp. Records experimental result so far. Interested in ordinary dust particles under electric light.

Remarks on upcoming lecture of JH's son [Alexander], and on glacial movement.

Clarifies that JT does not believe moon radiates cold itself, but effects are 'as if' it did. Relates this to atmosphere.

JT's paper on polarization of sky light suggests that neutral points are functions of cloud density. This verifies JH's earlier explanation of blue sky color. Incomplete polarization. Cause of blue color in water. Corrects note on W. A. Miller's observations of rainbows.

No summary available.