Sends copy of JT's '3rd Memoir,' along with specimens of liquid mercury ethyl and mercury methyl from discoverers Edward Frankland and B. F. Duppa.

Corrects misinformation about refraction and dispersion of mercury ethyl and mercury methyl.

Describes experiment involving viewing spectrum of a light flash as it advances and recedes. [Marked 'not sent on further consideration.']

Comments on excellence of the lecture at the Royal Institution of JH's son [Alexander].

Thanks for note [see JT's 1866-5-26] on improvement of the lecturing style of JH's son [Alexander]. JH's son has studied lecture's subject deeply and loves science; JH hopes will be physics professor at a 'considerable institution.'

Asks whether Michael Faraday's work with glass resulted in improved manufacturing or if rather its main scientific value was in discovery of diamagnetism.

Believes Michael Faraday's boro-silicate of lead has not been used for telescopes, but JH and others have tried using it for other optical purposes. Describes method for producing veinless flint glass.

JT has suggested that JH's son [Alexander] be appointed to position in Royal School of Mines, but colleagues, unwisely, JT thinks, want someone more well-known.

Thanks for paper on action of solar and electric light on vapors, which should give JT further insight into blue color of sky and polarization of skylight. Comments on the latter. JH's son [Alexander] is working hard at Glasgow.

Is studying vesicles. JH's son [Alexander] may yet get Royal School of Mines appointment.

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.

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.

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], suggesting possible cause of blue cloud color and eventual whitening of light.

Asks JH to review paper on blue color of sky, polarization of skylight, and polarization of light by cloudy matter.

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.

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.

Thanks for JH's suggestions on JT's outline of comet speculations. [G. B.] Airy, too, has replied. Includes more speculations on 'envelopes' and nucleus of comet.

Suggests experiments with regard to polarization and vaporization, and comets' tails.