Sir John Herschel wrote to my father from the Cape:—
FROM SIR JOHN HERSCHEL TO MR. SOMERVILLE.
Feldhausen, near Wynberg, C.G.H., July 17th, 1830.
Since our arrival here, I have, I know in many instances, maintained or established the character of a bad correspondent; and really it is not an inconvenient character to have established. Only, in your case, I should be very sorry to appear in that, or any other negligent or naughty light; but you, I know, will allow for the circumstances which have occasioned my silence. Meanwhile, I am not sorry that the execution of an intention I had more than once formed should have been deferred, till we read in the papers of the well-judged and highly creditable notice (creditable I mean to the government pro tempore) which His Majesty has been pleased to take of Mrs. Somerville's elaborate works. Although the Royal notice is not quite so swift as the lightning in the selection of its objects, it agrees with it in this, that it is attracted by the loftiest; and though what she has performed may seem so natural and easy to herself, that she may blush to find it fame; all the rest of the world will agree with me in rejoicing that merit of that kind is felt and recognised at length in the high places of the earth. This, and the honourable mention of Airy by men of both parties in the House of Commons about the same time, are things that seem to mark the progress of the age we live in; and I give Peel credit for his tact in perceiving this mode of making a favourable impression on the public mind.
We are all going on very comfortably, and continue to like the Cape as a place of (temporary) residence as much or more than at first. The climate is so very delicious.... The stars are most propitious, and, astronomically speaking, I can now declare the climate to be most excellent. Night after night, for weeks and months, with hardly an interruption, of perfect astronomical weather, discs of stars reduced almost to points, and tranquilly gliding across the field of your telescope. It is really a treat, such as occurs once or perhaps twice a year in England—hardly more. I had almost forgotten that by a recent vote of the Astronomical Society I can now claim Mrs. Somerville as a colleague. Pray make my compliments to her in that capacity, and tell her that I hope to meet her there at some future session....
Yours very faithfully,
H.W. Herschel.
To William Somerville, Esq.
Spectrum analysis has shown that there is a vast quantity of self-luminous gaseous matter in space, incapable of being reduced into stars, however powerful the telescope through which it is observed. Hence the old opinion once more prevails, that this is the matter of which the sun and stellar systems have been formed, and that other stellar systems are being formed by slow, continuous condensation. The principal constituents of this matter are, the terrestrial gases, hydrogen, and nitrogen. The yellow stars, like the sun, contain terrestrial matter. The nebulous and stellar constituents were chiefly discovered by Dr. Huggins.
Somerville and I were always made welcome by Sir James South, and at Campden Hill I learnt the method of observing, and sometimes made observations myself on the double stars and binary systems, which, worthless as they were, enabled me to describe better what others had done. One forenoon Somerville and I went to pay a visit to Lady South. Sir James, who was present, said, "Come to the observatory, and measure the distance of Mercury from the sun; for they are in close approximation, and I wish to see what kind of observation you will make." It was erroneous, as might have been expected; but when I took the mean of several observations, it differed but little from that which Sir James South had made; and here I learnt practically the importance of taking the mean of approximate quantities.