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Admiral Smyth’s - Sidereal Chromatics

PART II. (c.) (cont.)

DOUBLE STAR COLOURS CONTINUED

Colour Blindness.

In the first volume of my Cycle of Celestial Objects, pages 302 and 303 (and see ante, pp. 15, 16), I instanced what is now termed “colour blindness,” or the abnormal peculiarity of certain eyes in their being unable to distinguish colours correctly, and yet capable of proper action in every other use of them. Every one knows those violent cases of it where a person cannot scan green from red, and other such egregious contrasts, and would not admit such an individual’s observations of colours at all; but it is by no means so generally known as it should be, that a personal equation of greater or less amount exists in every ease, even without wishing to push tintism ad infinitum. The reason of the faulty colouring of so many artists by vocation is, that they really are not aware of many of the refinements of colour; their eyes not perceiving them, their fingers cannot render them. In one of the most intense examples, however, of this chromatic personal equation, although the person could not distinguish so bright a scarlet as the flower of the pomegranate from the genuine green of its leaf. I have had abundant proof that his eye was able to perceive brightness, independent of colour, as acutely, if not much more so, than the generality of men. [15] It should, however, be observed, that there is to the most normal vision a sensible presence of the red element in either violet or lilac, and the various hues indiscriminately termed purple.

The Australian telescope. [*72]

By thus calling for an increase of energy in the eye-estimation of sidereal colours, it will be seen that we are not insensible to the advantages of the instrumental method, despite all the perplexities which it now labours under; and we may hope that these advantages will not be lost sight of. If it be true that the Government is about to send a large reflector to Australia to observe the southern nebulæ, how desirable that it should also forward another to a tropical region for oh-serving the planets, and for making chromatic observations of the stars. The Australian telescope will have more time sufficient work with the nebulæ, and the planets with their faint satellites will be low down in the north there, while we have them low in the south here; but the equatorial telescope will have them in its zenith; and it may be elevated on some table-land there far higher into the atmosphere than the Australian one can be. This is a very important matter where colours rather than brightness are concerned: for a want of the latter may be corrected merely by using a larger aperture; but a distortion of the former, once introduced, is utterly irremediable under the existing theory.

The Melbourne telescope.

Since the above allusion was printed in the Speculum Hartwellian, the subject of the Southern Telescope has. been repeatedly agitated, with a prospect of eventual success, although it has unfortunately hung fire. In the meantime a very unexpected event occurred. Sir Henry Berkly, Governor of the new and energetic colony of Victoria, wrote on the 23rd of July, 1862, to the Duke of Newcastle, the Colonial Secretary of State, that a commencement had been made for the erection of an astronomical observatory at Melbourne, and that a sum of 4,500l. had been voted by the local legislature for its completion; and, as it was also resolved to employ a telescope of greater power than any previously used in the southern hemisphere, he was desirous of obtaining the advice of the Royal Society towards effecting this object.
After much correspondence on this praiseworthy proposal, it was resolved that the telescope to be recommended [*73] should be made by Mr. Grubb or Dublin, under the superintendence of Lord Rosse, Dr. Robinson of Armagh, Mr. De la Rue, and Mr. Lassell. The estimate of Mr. Grubb for the probable cost of the instrument, two four-foot specula, a polishing-machine, and a one-horse power steam-engine, was 5,000l.; but, as several things in the construction were necessarily experimental, it was put at 6,000l. as a safety valve.

Lassell’s letter.

These consultations were barely concluded when General Sabine, the President of the Royal Society, received a letter from Mr. William Lassell dated 22nd of July, 1863, couched in these terms:-

On the occasion of my temporary visit to England, I have had the opportunity of looking into some of the correspondence respecting the proposed four-foot telescope for Melbourne, and in consequence I should be glad to be allowed to state that I do not intend to continue my observations with the telescope of this size now erected in Malta, and described in this correspondence, beyond the period of twelve, or at most eighteen, months from the present time; and that, if this equatorial should meet the requirements of the Melbourne Committee, I shall then be glad to place it at their disposal.

Subsequently Mr. Lassell himself explained, answering a query, that he means to place his grand telescope at the disposal of the Melbourne Committee as a GIFT, though under certain conditions which would satisfy him that it would be wisely and usefully employed; and while it remains to be seen whether this nobly liberal overture is duly accepted, all hands ought to remember Sir John Herschel’s logical declaration, “The DAYS THAT PASS BETWEEN THIS AND WHEN THE SURVEY OF THE SOUTHERN HEAVEN BEGINS, ARE EACH AN IRRETRIEVABLE LOSS TO ASTRONOMY! ”

I’Envoy

We thus close our exhortations with a well-sounded and unmistakable charge, from one of the ablest and most zealous astronomers of the age. This awful warning would seem amply sufficient to make the sons of Urania bestir themselves, [*74] at all events; and the amateurs of the present day are not only better furnished with efficient telescopes than were their brethren of yore, but they are also stimulated and aided by trustworthy treatises available to all men — not as of erst written in noli me tangere of crabbed quodlibets in a dead language. The incurring that irretrievable loss to science pointed out by Sir John Herschel, becomes the more heinous since, as just said, the means of observing have become so easily obtainable; and, what is more, we have attained a commanding station from which the labours of our worthy predecessors have rendered a further advance comparatively easy. Indeed there is so broad a basis of former work to rely upon, that we know exactly what to aim at now; and every successive stratum will help us to raise a pyramid of knowledge, the apex of which may finally reach the summum bonum in of the cultivated mind’s expectation.

ENDNOTES

[15] Some contemporary elders may be surprized at my not having here instanced the hackneyed story of Dalton — Atomic Dalton — how he bought pink stockings in mistake for drab-coloured; how he went to the meeting arrayed in them; how he s candalized the quakers and quaquerettes ; and how the elders threatened to read him out of the Society for his gross misdemeanour. Now I made no allusion to this for the simple reason that, on inquiry, I could place no reliance on it, albeit one of my informers was a Royal Duke. It seems merely to have been a ben trovato of some wag, who was aware of the aberration of vision in my philosophical and able friend.