Autobiography of Sir George Biddell Airy by George Biddell Airy (e reader for manga .TXT) 📕

only their Personal Equation, but also the gradual change of Personal Equation. On Sept. 30th Otto Struve formally wrote his thanks for assistance rendered.

"For the determination of the longitude of Valencia, which was carried out in this year, various methods were discussed, but the plan of sending chronometers by mail conveyance was finally approved. From London to Liverpool the chronometers were conveyed by the railways, from Liverpool to Kingstown by steamer, from Dublin to Tralee by the Mail Coaches, from Tralee to Cahersiveen by car, from Cahersiveen to Knightstown by boat, and from Knightstown to the station on the hill the box was carried like a sedan-chair. There were numerous other arrangements, and all succeeded perfectly without a failure of any kind. Thirty pocket chronometers traversed the line between Greenwich and Kingstown about twenty-two times, and that between Kingstown and Valencia twenty times. The chronometrical longitudes of Liverpool Observatory, Kingstown Station, and Valencia Station are 12m 0.05s, 24m 31.17s, 41m 23.25s; the geodetic longitudes, computed from elements which I published long ago in the Encyclopaedia Metropolitana, are 12m 0.34s, 24m 31.47s, 41m 23.06s. It appears from this that the elements to which I have alluded represent the form of the Earth here as nearly as is possible. On the whole, I think it probable that this is the best arc of parallel that has ever been measured.

"With regard to the Maine Boundary: on May 7th Col. Estcourt, the British Commissioner, wrote to me describing the perfect success of following out my plan: the line of 64 miles was cut by directions laid out at the two ends, and the cuttings met within 341 feet. The country through which this line was to pass is described as surpassing in its difficulties the conception of any European. It consists of impervious forests, steep ravines, and dismal swamps. A survey for the line was impossible, and a tentative process would have broken the spirit of the best men. I therefore arranged a plan of operations founded on a determination of the absolute latitudes and the difference of longitudes of the two extremities. The difference of longitudes was determined by the transfer of chronometers by the very circuitous route from one extremity to the other; and it was necessary to divide the whole arc into four parts, and to add a small part by measure and bearing. When this was finished, the azimuths of the line for the two ends were computed, and marks were laid off for starting with the line from both ends. One party, after cutting more than forty-two miles through the woods, were agreeably surprised, on the brow of a hill, at seeing directly before them a gap in the woods on the next line of hill; it opened gradually, and proved to be the line of the opposite party. On continuing the lines till they passed abreast of each other, their distance was found to be 341 feet. To form an estimate of the magnitude of this error, it is to be observed that it implies an error of only a quarter of a second of time in the difference of longitudes; and that it is only one-third (or nearly so) of the error which would have been committed if the spheroidal form of the Earth had been neglected. I must point out the extraordinary merit of the officers who effected this operation. Transits were observed and chronometers were interchanged when the temperature was lower than 19 deg. below zero: and when the native assistants, though paid highly, deserted on account of the severity of the weather, the British officers still continued the observations upon whose delicacy everything depended.

"Of private history: From July 3rd to Aug. 13th I was in Ireland with my wife. This was partly a business journey in connection with the determination of the longitude of Valencia. On Jan. 4th I asked Lord Lyndhurst (Lord Chancellor) to present my brother to the living of Helmingham, which he declined to do: but on Dec. 12th he offered Binbrooke, which I accepted for my brother."


1845

"A map of the Buildings and Grounds of the Observatory was commenced in 1844, and was still in progress.--On Mar. 19th I was employed on a matter which had for some time occupied my thoughts, viz., the re-arrangement of current manuscripts. I had prepared a sloping box (still in use) to hold 24 portfolios: and at this time I arranged papers A, and went on with B, C, &c. Very little change has been made in these.--In reference to the time given to the weekly report on Meteorology to the Registrar General, the Report to the Board of Visitors contains the following paragraph: 'The devotion of some of my assistants' time and labour to the preparation of the Meteorological Report attached to the weekly report of the Registrar General, is, in my opinion, justified by the bearing of the meteorological facts upon the medical facts, and by the attention which I understand that Report to have excited.'--On Dec. 13th the sleep of Astronomy was broken by the announcement that a new planet, Astraea, was discovered by Mr Hencke. I immediately circulated notices.--But in this year began a more remarkable planetary discussion. On Sept. 22nd Challis wrote to me to say that Mr Adams would leave with me his results on the explanation of the irregularities of Uranus by the action of an exterior planet. In October Adams called, in my absence. On Nov. 5th I wrote to him, enquiring whether his theory explained the irregularity of radius-vector (as well as that of longitude). I waited for an answer, but received none. (See the Papers printed in the Royal Astronomical Society's Memoirs and Monthly Notices).--In the Royal Society, the Royal Medal was awarded to me for my Paper on the Irish Tides.--In the Royal Astronomical Society I was President; and, with a speech, delivered the Medal to Capt. Smyth for the Bedford Catalogue of Double Stars.--On Jan. 21st I was appointed (with Schumacher) one of the Referees for the King of Denmark's Comet Medal: I have the King's Warrant under his sign manual.--The Tidal Harbour Commission commenced on Apr. 5th: on July 21st my Report on Wexford Harbour (in which I think I introduced important principles) was communicated. One Report was made this year to the Government.--In the matter of Saw Mills (which had begun in 1842), I had prepared a second set of plans in 1844, and in this year Mr Nasmyth made a very favourable report on my plan. A machinist of the Chatham Dock Yard, Sylvester, was set to work (but not under my immediate command) to make a model: and this produced so much delay as ultimately to ruin the design.--On Jan. 1st I was engaged on my Paper 'On the flexure of a uniform bar, supported by equal pressures at equidistant points.'" (This was probably in connection with the support of Standards of Length, for the Commission. Ed.).--In June I attended the Meeting of the British Association at Cambridge, and on the 20th I gave a Lecture on Magnetism in the Senate House. The following quotation relating to this Lecture is taken from a letter by Whewell to his wife (see Life of William Whewell by Mrs Stair Douglas): "I did not go to the Senate House yesterday evening. Airy was the performer, and appears to have outdone himself in his art of giving clearness and simplicity to the hardest and most complex subjects. He kept the attention of his audience quite enchained for above two hours, talking about terrestrial magnetism."--On Nov. 29th I gave evidence before a Committee of the House of Commons on Dover Harbour Pier.

"With respect to the Magnetical and Meteorological Establishment, the transactions in this year were most important. It had been understood that the Government establishments had been sanctioned twice for three-year periods, of which the second would expire at the end of 1845: and it was a question with the scientific public whether they should be continued. My own opinion was in favour of stopping the observations and carefully discussing them. And I am convinced that this would have been best, except for the subsequent introduction of self-registering systems, in which I had so large a share. There was much discussion and correspondence, and on June 7th the Board of Visitors resolved that 'In the opinion of the Visitors it is of the utmost importance that these observations should continue to be made on the most extensive scale which the interests of those sciences may require.' The meeting of the British Association was held at Cambridge in June: and one of the most important matters there was the Congress of Magnetic Philosophers, many of them foreigners. It was resolved that the Magnetic Observatory at Greenwich be continued permanently. At this meeting I proposed a resolution which has proved to be exceedingly important. I had remarked the distress which the continuous two-hourly observations through the night produced to my Assistants, and determined if possible to remove it. I therefore proposed 'That it is highly desirable to encourage by specific pecuniary reward the improvement of self-recording magnetical and meteorological apparatus: and that the President of the British Association and the President of the Royal Society be requested to solicit the favourable consideration of Her Majesty's Government to this subject,' which was adopted. In October the Admiralty expressed their willingness to grant a reward up to L500 . Mr Charles Brooke had written to me proposing a plan on Sept. 23rd, and he sent me his first register on Nov. 24th. On Nov. 1st the Treasury informed the Admiralty that the Magnetic Observatories will be continued for a further period.

"The Railway Gauge Commission in this year was an important employment. The Railways, which had begun with the Manchester and Liverpool Railway (followed by the London and Birmingham) had advanced over the country with some variation in their breadth of gauge. The gauge of the Colchester Railway had been altered to suit that of the Cambridge Railway. And finally there remained but two gauges: the broad gauge (principally in the system allied with the Great Western Railway); and the narrow gauge (through the rest of England). These came in contact at Gloucester, and were likely to come in contact at many other points--to the enormous inconvenience of the public. The Government determined to interfere, beginning with a Commission. On July 3rd Mr Laing (then on the Board of Trade) rode to Greenwich, bearing a letter of introduction from Sir John Lefevre and a request from Lord Dalhousie (President of the Board of Trade) that I would act as second of a Royal Commission (Col. Sir Frederick Smith, Airy, Prof. Barlow). I assented to this: and very soon began a vigorous course of business. On July 23rd and 24th I went with Prof. Barlow and our Secretary to Bristol, Gloucester, and Birmingham: on Dec. 17th I went on railway experiments to Didcot: and on Dec. 29th to Jan. 2nd I went to York, with Prof. Barlow and George Arthur Biddell, for railway experiments. On Nov. 21st I finished a draft Report of the Railway Gauge Commission, which served in great measure as a basis for that adopted next year.

"Of private history: I wrote to Lord Lyndhurst on Feb. 20th, requesting an exchange of the living to which he had presented my brother in Dec. 1844 for that of Swineshead: to which he consented.--On Jan. 29th I went with my wife on a visit to my uncle George Biddell, at Bradfield St George, near Bury.--On June 9th I went into the mining district of Cornwall with George Arthur Biddell.--From Aug. 25th to Sept. 26th I was travelling in France