The next step to be taken is to verify the accuracy of the above statements regarding the grouping of the stars into lines and curves; assuming that the examiner has, like myself, been convinced of their reality. As a test of this, as well as an example let us examine Plates 2 to 9, upon which the eye readily detects many groups of stars arranged in lines and in curves, each of them containing several stars; similar configurations to these can be seen on the other plates, and if I had chosen to print hundreds of others that are in my cabinets, each covering four square degrees in the sky, similar configurations would be seen upon them.

This persistency of the lines and curves of stars on the plates leaves no room for doubt that they are the effects of physical causes, and cannot be due to coincidence only; and when the photographs of the spiral and other nebulæ are examined a reasonable explanation of the formation of the curves and lines will be made manifest.

It is not my intention to submit elaborate arguments, or mathematical formulæ, in the discussion of the photographic evidence contained in this and in the first volume of my photographs–these will in the future, when a sufficient interval of time has elapsed, occupy the thoughts of the correlators, the measurers, the computers and of the mathematicians–my aim is now to point out the evidence, and the relationships to each other of the several classes of objects that are found depicted, untouched by hand-work, upon the photographs.

A century has elapsed since Laplace suggested that the sun, and planets, might have been evolved out of nebulous matter, but his imagination did not lead him to realize the much larger idea that stellar systems might also have been evolved from matter similar in its constitution.

I now propose to submit a series of photographic copies of my original negatives from which we may obtain strong evidence, if not complete demonstration, of the evolution of stellar systems.

The first part of the series will consist of photographs of rich fields of stars, and of clusters showing various degrees of concentration; these will be followed by a series of the spiral nebulæ some of them symmetrical in form, and others less symmetrical though clearly spiral. Following these again will be a number of nebulæ of circular, annular, and irregular forms, and, lastly, nebulæ consisting of large areas of cloud-like matter having irregular structural characteristics.

The appearances to which I now wish to draw special attention in the examination of these photographs are the numerous curves and lines of stars that are associated together in separate groups. The stars are of nearly equal magnitude; of approximately equal distances apart in each group, and the groups are independent of each other and of the surrounding stars.

1866

In this year the cube of the Transit Circle was pierced, to permit reciprocal observations of the Collimators without raising the instrument. This involved the construction of improved Collimators, which formed the subject of a special Address to the Members of the Board of Visitors on Oct. 21st 1865.—From the Report to the Visitors it appears that “On May 23rd 1865, a thunderstorm of great violence passed very close to the Observatory. After one flash of lightning, I was convinced that the principal building was struck. Several galvanometers in the Magnetic Basement were destroyed. Lately it has been remarked that one of the old chimneys of the principal building had been dislocated and slightly twisted, at a place where it was surrounded by an iron stayband led from the Telegraph Pole which was planted upon the leads of the Octagon Room.”—“On consideration of the serious interruptions to which we have several times been exposed from the destruction of our open-air Park-wires (through snow-storms and gales), I have made an arrangement for leading the whole of our wires in underground pipes as far as the Greenwich Railway Station.”—“The Committee of the House of Commons, to whom the Greenwich and Woolwich Line of the South Eastern Railway was referred, finally assented to the adoption of a line which I indicated, passing between the buildings of the Hospital Schools and the public road to Woolwich.”—“The Galvanic Chronometer attached to the S. E. Equatoreal often gave us a great deal of trouble. At last I determined, on the proposal of Mr Ellis, to attempt an extension of Mr R. L. Jones's regulating principle.

1846

“On Nov. 7th I proposed a change in the form of Estimates for the Observatory. The original astronomical part was provided by the Admiralty, and the new magnetical and meteorological part was provided by the Treasury: and the whole Estimates and Accounts of the Observatory never appeared in one public paper. I proposed that the whole should be placed on the Navy Estimates, but the Admiralty refused. I repeated this in subsequent years, with no success. Meantime I always sent to the Admiralty a duplicate of my Treasury Estimate with the proper Admiralty Estimate.—Stephenson's Railway through the lower part of the Park, in tunnel about 850 feet from the Observatory, was again brought forward. On Feb. 20th it was put before me by the Government, and on March 9th I made experiments at Kensal Green, specially on the effect of a tunnel: which I found to be considerable in suppressing the tremors. On May 6th I made my Report, generally favourable, supposing the railway to be in tunnel. On May 13th I, with Mr Stephenson, had an interview at the Admiralty with Lord Ellenborough and Sir George Cockburn. The Earl appeared willing to relax in his scruples about allowing a railway through the Park, when Sir George Cockburn made a most solemn protest against it, on the ground of danger to an institution of such importance as the Observatory. I have no doubt that this protest of Sir George Cockburn's really determined the Government.

HISTORY OF HIS LIFE AFTER HIS RESIGNATION OF OFFICE.

On the 16th of August 1881 Airy left the Observatory which had been his residence for nearly 46 years, and removed to the White House. Whatever his feelings may have been at the severing of his old associations he carefully kept them to himself, and entered upon his new life with the cheerful composure and steadiness of temper which he possessed in a remarkable degree. He was now more than 80 years old, and the cares of office had begun to weigh heavily upon him: the long-continued drag of the Transit of Venus work had wearied him, and he was anxious to carry on and if possible complete his Numerical Lunar Theory, the great work which for some years had occupied much of his time and attention. His mental powers were still vigorous, and his energy but little impaired: his strong constitution, his regular habits of life, the systematic relief which he obtained by short holiday expeditions whenever he found himself worn with work, and his keen interest in history, poetry, classics, antiquities, engineering, and other subjects not immediately connected with his profession, had combined to produce this result. And in leaving office, he had no idea of leaving off work; his resignation of office merely meant for him a change of work.

FROM MARCH 15TH 1828 TO JAN. 1ST 1836.

1828

“I attended a meeting of the Board of Longitude on Apr. 3rd. And again on June 4th; this was the last meeting: Sheepshanks had previously given me private information of the certainty of its dissolution.—On Apr. 4th I visited Mr Herschel at Slough, where one evening I saw Saturn with his 20-foot telescope, the best view of it that I have ever had.—In June I attended the Greenwich Observatory Visitation.— Before my election (as Plumian Professor) there are various schemes on my quires for computation of transit corrections, &c. After Apr. 15th there are corrections for deficient wires, inequality of pivots, &c. And I began a book of proposed regulations for observations. In this are plans for groups of stars for R.A. (the Transit Instrument being the only one finished): order of preference of classes of observations: no reductions to be made after dinner, or on Sunday: no loose papers: observations to be stopped if reductions are two months in arrear: stars selected for parallax.—The reduction of transits begins on Apr. 15th. On May 15th Mr Pond sent me some moon-transits to aid in determining my longitude.—Dr Young, in a letter to me of May 7th, enquires whether I will accept a free admission to the Royal Society, which I declined. On May 9th I was elected to the Astronomical Society.—Towards the end of the year I observed Encke's Comet: and determined the latitude of the Observatory with Sheepshanks's repeating circle.—On my papers I find a sketch of an Article on the Figure of the Earth for the Encyclopaedia Metropolitana.