LETTERS TO DR ROMNEY ROBINSON, 1875–1879 AND 1880–1881.

The first group of the following letters have been selected from a series belonging to the period 1875-9, carefully arranged in years evidently by Dr Robinson himself. The remaining part is printed from duplicate typewritten copies preserved among Prof. Stokes’ manuscripts.

A long correspondence on anemometers of the year 1877 is omitted: reference may be made to Dr Robinson's memoir, Phil. Trans. 1878, also to Math, and Phys. Papers, Vol. v. pp. 73–99.

Cambridge, 4th Jan. 1875.

…I heard to-day from Mrs Harcourt. The instrument she referred to is a finely graduated circle, with telescopes for measuring refractive indices, which she gave to me for my life time, leaving the ultimate destination yet to be settled. I was not aware this had been sent to you, and I am not sure that it was. When I was at Nuneham shortly after Mr Harcourt's death, she expressed a wish to give us each some instrument of his. She may have mentioned the refractometer as for you (I cannot now recollect), and I may have suggested that you had an equivalent instrument already, and that it might be very valuable to me as I did not possess one. If she had thought of giving it to you she may have recollected the intention and supposed it had been actually sent. I could not suppose that she meant to offer to me an instrument she had already given to you.

I am not sure whether I mentioned that the Chances have made an experiment on a silico-titanic glass. Hopkinson, Senior Wrangler in 1871, who is their scientific adviser, had the superintendence of it. He sent me a specimen of the glass.