Hopes that JH will be able to visit Newcastle.

Is working on the correction of calculation errors [see JH's 1863-5-31]; GA and his assistants will deal with the problem of proofreading.

A letter of introduction asking GA to admit Major Robertson and his sisters to the observatory.

Saw J. B. N. Hennessey [who had just come from India] at a Greenwich visitation day, but did not have time to speak to him there. JH will invite him to Collingwood.

Responds to JH [see JH's 1863-6-2] about basic rules for admission to the observatory [for JH's future guidance]; GA discourages the visit of ladies 'who understand nothing and learn nothing.'

Asks whether JT can reprint JH's letters on the British modular standard of length, which letters were published in the Athenaeum.

Have made several of JH's actinometers but have always experienced difficulty with the fluid, ammonia sulphate of copper. Can some other fluid be used? They are now making two actinometers for a foreign observatory and would like to make them as accurate as possible.

Passes on recent reports of good news that daughter Caroline is improving, and that JH's wife, Margaret, survived the journey well. [Margaret went to Dublin to be with Caroline when she became very ill at the birth of her daughter Kathleen.]

Gives permission to reprint letters to Athenaeum on standard of length, in light of recent bill to metricize. Requests as many copies as possible.

Comments on GA's activity in correcting the calculation errors [see GA's 1863-6-2].

Correcting work is gradually drawing to a close [see JH's 1863-6-4].

Finds there is not one of JH's actinometers at Kew; would be grateful if he could inform him who has been working with one.

Will send as many copies as possible of JT's reprinting of JH's letters to the Athenaeum. Asks if JH has seen Thomas Rawson Birks's book on matter and ether.

Is sorry to hear that JH is unable to attend the B.A.A.S. meeting. Has been working on a new formula for thallium, and will forward a sample if required.

Thanks for the information. Has written to Henry Barrow, and to Negretti and Zambra. The latter can supply actinometers for 14 guineas; too expensive for him. Barrow has just replied that he can supply for 6 guineas.

As he has been absent on the continent he has been unable to accept any of JH's kind invitations. His stay in Europe has been short, but full of gratification.

Sends the appendix to the volume being printed and hopes he can quote the extract from JH's letter. Comments on James Croll's theories. Points out a mistake in the report from the Morning Post.

Seeks WW's signature for the Thomas Maclear Memorial. JH's daughter Julia has been ill.

Discusses dispersal of copies of letter against adoption of 'French metre' [see JH's 1863-6-4].

Would be pleased to receive a sample of thallium. Queries regarding the manufacture of pure nickel and cobalt.