I am,
My dear Mr Vice-Chancellor,
Your very faithful servant,
G.B. AIRY.
The Rev. Dr Cartmell,
&c. &c.
Vice-Chancellor of the University of Cambridge.
1867
"In this year it was arranged that my Treasury accounts were to be transferred to the Admiralty, making the simplification which I had so long desired.—From the Report to the Visitors it appears that a relic of the Geodetic operations commenced in 1787 for connecting the Observatories of Greenwich and Paris, in the shape of an observing cabin on the roof of the Octagon Room, was shifted and supported in such a manner that the pressure on the flat roof was entirely avoided.—With regard to the Transit Circle, the new Collimators with telescopes of seven inches aperture had been mounted. When the Transit Telescope directed vertically is interposed, the interruptions in the central cube impair the sharpness of definition, still leaving it abundantly good for general use. It had been regarded as probable that the astronomical flexure of the telescope, after cutting away small portions of the central cube, would be found sensibly changed: and this proved to be the case. The difference of flexures of the two ends has been altered more than a second of arc.—Referring to a new Portable Altazimuth which had lately been tested, the Report states as follows: 'I may mention that a study of defects in the vertical circle of a small Altazimuth formerly used by me, and an inspection of the operations in the instrument-maker's work-shop, have convinced me that the principal error to be feared in instruments of this class is ovality of the graduated limb; this cannot be eliminated by two microscopes, and such an instrument should never be fitted with two only. Our instrument has four.'—'In Osler's Anemometer, a surface of 2 square feet is now exposed to the wind instead of one foot as formerly; and the plate is supported by weak vertical springs instead of rods running on rollers. Its indications are much more delicate than formerly.'—'The Meteors on Nov. 14th were well observed. Eight thousand and three hundred were registered. The variations of frequency at different times were very well noted. The points of divergence were carefully determined.'—Referring to the gradual improvement in the steadiness of chronometers from 1851 to 1866, it appears that from 1851 to 1854 the 'trial number' (which is a combination of changes of weekly rate representing the fault of the chronometer) varied from 34.8s to 52.5s, while from 1862 to 1866 it varied from 21.2s to 25.8s.—The following statement will shew the usual steadiness of the Great Clock on the Westminster Palace: On 38 per cent. of days of observation, the clock's error was below 1s. On 38 per cent, the error was between 1s and 2s. On 21 per cent. it was between 2s and 3s. On 2 per cent. between 3s and 4s. On 1 per cent. between 4s and 5s.—The Report contains an account of the determination of the longitude of Cambridge U.S. by Dr B. A. Gould, by means of galvanic currents through the Atlantic Cable, in the spring of 1867: and advantage was taken of this opportunity for re-determining the longitude of Feagh Main near Valencia in Ireland. The longitude of Feagh Main, found by different methods is as follows: By chronometers in 1844, 41m 23.23s; by galvanic communication with Knight's Town in 1862, 41m 23.37s; by galvanic communication with Foilhommerum in 1866, 41m 23.19s. The collected results for longitude of Cambridge U.S. from different sources are: By moon-culminators (Walker in 1851, and Newcomb in 1862-3), 4h 44m 28.42s and 4h 44m 29.56s respectively; by Eclipses (Walker in 1851), 4h 44m 29.64s; by occultations of Pleiades (Peirce 1838-1842, and 1856-1861), 4h 44m 29.91s and 4h 44m 30.90s respectively; by chronometers (W. C. Bond in 1851, and G. P. Bond in 1855), 4h 44m 30.66s and 4h 44m 31.89s respectively; by Atlantic Cable 1866, 4h 44m 30.99s.—After noticing that many meteorological observatories had suddenly sprung up and had commenced printing their observations in detail, the Report continues thus: 'Whether the effect of this movement will be that millions of useless observations will be added to the millions that already exist, or whether something may be expected to result which will lead to a meteorological theory, I cannot hazard a conjecture. This only I believe, that it will be useless, at present, to attempt a process of mechanical theory; and that all that can be done must be, to connect phenomena by laws of induction. But the induction must be carried out by numerous and troublesome trials in different directions, the greater part of which would probably be failures.'—There was this year an annular eclipse; I made large preparations at the limits of the annularity; failed entirely from very bad weather."—In this year Airy contributed a Paper to the Institution of Civil Engineers 'On the use of the Suspension Bridge with stiffened roadway for Railway and other Bridges of Great Span,' for which a Telford Medal was awarded to him by the Council of the Institution. And he communicated several Papers to the Royal Society and the Royal Astronomical Society.
Of private history: There was the usual visit to Playford in
January.—In April there was a short run to Alnwick and the
neighbourhood, in company with Mr and Mrs Routh.—From June 27th to
July 4th he was in Wales with his two eldest sons, visiting Uriconium,
&c. on his return.—From August 8th to Sept. 7th he spent a holiday in
Scotland and the Lake District of Cumberland with his daughter
Christabel, visiting the Langtons at Barrow House, near Keswick, and
Isaac Fletcher at Tarn Bank.
In June of this year (1867) Airy was elected an Honorary Fellow of his
old College of Trinity in company with Connop Thirlwall, the Bishop of
St David's. They were the first Honorary Fellows elected by the
College. The announcement was made in a letter from the Master of
Trinity (W.H. Thompson), and Airy's reply was as follows:
ROYAL OBSERVATORY, GREENWICH,
LONDON, S.E.
1867, June 12th.
MY DEAR MASTER,
I am very much gratified by your kind note received this morning, conveying to me the notice that the Master and Sixteen Senior Fellows had elected me, under their new powers, as Honorary Fellow of the College.
It has always been my wish to maintain a friendly connection with my
College, and I am delighted to receive this response from the
College. The peculiar form in which the reference to the Statute
enables them to put it renders it doubly pleasing.