Autobiography of Sir George Biddell Airy, George Biddell Airy [best english books to read for beginners txt] 📗

however, Mr Adams has shewn that Burckhardt's Parallax is erroneous in formula and is numerically incorrect, sometimes to the amount of seven seconds. In consequence of this, every reduction of the Observations of the Moon, from 1830 to the present time, is sensibly erroneous. And the error is of such a nature that it is not easy, in general, to introduce its correction by any simple process.... The number of observations to the end of 1851 (after which time the parallax will be corrected in the current reductions) is about 2560. An expense approaching to L400 might be incurred in their reduction.' Subsequently I made application to the Admiralty, and the L400 was granted on Dec. 12th.--In the Report to the Visitors it is stated that with regard to the Transit Circle, changes are under contemplation in its reflection-apparatus: one of these changes relates to the material of the trough. 'Several years ago, when I was at Hamburgh, my revered friend Prof. Schumacher exhibited to me the pacifying effect of a copper dish whose surface had been previously amalgamated with quicksilver.......The Rev. Charles Pritchard has lately given much attention to this curious property of the metals, and has brought the practical operation of amalgamation to great perfection. Still it is not without difficulty, on account of a singular crystallization of the amalgam.'--With regard to the Chronograph, the Report states: 'The Barrel Apparatus for the American method of observing transits is not yet brought into use.... I have, however, brought it to such a state that I am beginning to try whether the Barrel moves with sufficient uniformity to be itself used as the Transit Clock. This, if perfectly secured, would be a very great convenience, but I am not very sanguine on that point.'--A change had been made in the Electrometer-apparatus: 'A wire for the collection of atmospheric electricity is now stretched from a chimney on the north-west angle of the leads of the Octagon Room to the Electrometer pole.... There appears to be no doubt that a greater amount of electricity is collected by this apparatus than by that formerly in use.'--As regards the Magnetical Observations: 'The Visitors at their last Meeting, expressed a wish that some attempt should be made to proceed further in the reduction or digest of the magnetical results, if any satisfactory plan could be devised. I cannot say that I have yet satisfied myself on the propriety of any special plan that I have examined.... I must, however, confess that, in viewing the capricious forms of the photographic curves, my mind is entirely bewildered, and I sometimes doubt the possibility of extracting from them anything whatever which can be considered trustworthy.'--Great progress had been made with the distribution of time. 'The same Normal Clock maintains in sympathetic movement the large clock at the entrance gate, two other clocks in the Observatory, and a clock at the London Bridge Terminus of the South-Eastern Railway.... It sends galvanic signals every day along all the principal railways diverging from London. It drops the Greenwich Ball, and the Ball on the Offices of the Electric Telegraph Company in the Strand;... All these various effects are produced without sensible error of time; and I cannot but feel a satisfaction in thinking that the Royal Observatory is thus quietly contributing to the punctuality of business through a large portion of this busy country. I have the satisfaction of stating to the Visitors that the Lords Commissioners of the Admiralty have decided on the erection of a Time-Signal Ball at Deal, for the use of the shipping in the Downs, to be dropped every day by a galvanic current from the Royal Observatory. The construction of the apparatus is entrusted to me. Probably there is no roadstead in the world in which the knowledge of true time is so important.'--The Report includes an account of the determination of the Longitude of Cambridge Observatory by means of galvanic signals, which appear to have been perfectly successful.--Under the head of General Remarks the following passage appears: 'The system of combining the labour of unattached computers with that of attached Assistants tends materially to strengthen our powers in everything relating to computation. We find also, among the young persons who are engaged merely to serve as computers, a most laudable ambition to distinguish themselves as observers; and thus we are always prepared to undertake any observations which may be required, although necessarily by an expenditure of strength which would usually be employed on some other work.'--Considerable work was undertaken in preparing a new set of maps of our buildings and grounds.--On Apr. 23rd there was a small fire in the magnetic observatory, which did little mischief.--In December I wrote my description of the Transit Circle.--Lieut. Stratford, the Editor of the Nautical Almanac, died, and there was some competition for the office. I was willing to take it at a low rate, for the addition to my salary: Mr Main--and I think Mr Glaisher--were desirous of exchanging to it: Prof. Adams was anxious for it. The Admiralty made the excellent choice of Mr Hind.--In October Faraday and I, at Lothbury, witnessed some remarkable experiments by Mr Latimer Clark on a galvanic current carried four times to and from Manchester by subterranean wires (more than 2000 miles) shewing the retardation of visible currents (at their maximum effect) and the concentration of active power. I made investigations of the velocity of the Galvanic Current.--I was engaged on the preliminary enquiries and arrangements for the Deal Time Ball.--With respect to the Westminster Clock; an angry paper was issued by Mr Vulliamy. In October I expostulated with Denison about his conduct towards Sir Charles Barry: on November 7th I resigned.--On Feb. 11th I was elected President of the Royal Astronomical Society.--In the Royal Institution I lectured on the Ancient Eclipses.--On Dec. 15th I was elected to the Academy of Brussels.--After preliminary correspondence with Sir W. Molesworth (First Commissioner of Works, &c.) and Sir Charles Barry (Architect of the Westminster Palace), I wrote, on May 14th, to Mr Gladstone about depositing the four Parliamentary Copies of Standards, at the Royal Observatory, the Royal Mint, the Royal Society, and within a wall of Westminster Palace. Mr Gladstone assented on June 23rd.--On Mar. 26th I wrote to Mr Gladstone, proposing to take advantage of the new copper coinage for introducing the decimal system. I was always strenuous about preserving the Pound Sterling. On May 10th I attended the Committee of the House of Commons on decimal coinage: and in May and September I wrote letters to the Athenaeum on decimal coinage.--I had always something on hand about Tides. A special subject now was, the cry about intercepting the tidal waters of the Tyne by the formation of the Jarrow Docks, in Jarrow Slake; which fear I considered to be ridiculous."

Of private history: "From Jan. 15th to 24th I was at Playford.--On Mar. 4th I went to Dover to try time-signals.--From June 24th to Aug. 6th I was at Little Braithwaite near Keswick, where I had hired a house, and made expeditions with members of my family in all directions. On July 28th I went, with my son Wilfrid, by Workington and Maryport to Rose Castle, the residence of Bishop Percy (the Bishop of Carlisle), and on to Carlisle and Newcastle, looking at various works, mines, &c.--On Dec. 24th I went to Playford."


1854

The chronograph Barrel-Apparatus for the American method of transits had been practically brought into use: "I have only to add that this apparatus is now generally efficient. It is troublesome in use; consuming much time in the galvanic preparations, the preparation of the paper, and the translation of the puncture-indications into figures. But among the observers who use it there is but one opinion on its astronomical merits--that, in freedom from personal equation and in general accuracy, it is very far superior to the observations by eye and ear."--The printing and publication of the Observations, which was always regarded by Airy as a matter of the first importance, had fallen into arrear: "I stated in my last Report that the printing of the Observations for 1852 was scarcely commenced at the time of the last meeting of the Visitors. For a long time the printing went on so slowly that I almost despaired of ever again seeing the Observations in a creditable state. After a most harassing correspondence, the printers were at length persuaded to move more actively, ... but the volume is still very much behind its usual time of publication."--"The Deal Time-Ball has now been erected by Messrs Maudslays and Field, and is an admirable specimen of the workmanship of those celebrated engineers. The galvanic connection with the Royal Observatory (through the telegraph wires of the South Eastern Railway) is perfect. The automatic changes of wire-communications are so arranged that, when the Ball at Deal has dropped to its lowest point, it sends a message to Greenwich to acquaint me, not with the time of the beginning of its fall (which cannot be in error) but with the fact that it has really fallen. The Ball has several times been dropped experimentally with perfect success; and some small official and subsidiary arrangements alone are wanting for bringing it into constant use."--The operations for the galvanic determination of the longitude of Brussels are described, with the following conclusion: "Thus, about 3000 effective signals were made, but only 1000 of these were admissible for the fundamental objects of the operation. The result, I need scarcely remark, claims a degree of accuracy to which no preceding determination of longitude could ever pretend. I apprehend that the probable error in the difference of time corresponds to not more than one or two yards upon the Earth's surface.--A careful scheme had been arranged for the determination of the longitude of Lerwick, but 'unfortunately, the demand for chronometers caused by our large naval armament has been so considerable that I cannot reckon on having at my disposal a sufficient number to carry on this operation successfully; and I have, therefore, unwillingly deferred it to a more peaceful time.'--The covering stone of Halley's Tomb in Lee Churchyard was much shattered, and I applied to the Admiralty for funds for its complete restoration: these were granted on Feb. 3rd.--In this year, under my cognizance, L100 was added to the Hansen grant.--I had much correspondence and work in connection with the printing of Maclear's work at the Cape of Good Hope. In June, all accounts, &c. about the Transit Circle were closed at the Admiralty, and the instrument was completely mounted at the Cape.--Dr Scoresby (who in his own way was very imperious) had attacked my methods of correcting the compass in iron ships: I replied in a letter to the Athenaeum on Oct. 17th.--I made enquiries about operations for determining the longitude of Vienna, but was utterly repelled by the foreign telegraph offices.--In the Royal Astronomical Society; I prepared the Address on presenting the Medal to Ruemker.--In Melbourne University: The first letter received was from the Chancellor of the University dated Jan. 26th, requesting that Sir John Herschel, Prof. Malden, Mr Lowe (subsequently Chancellor of the Exchequer), and I would select professors. We had a great deal of correspondence, meetings, examination of testimonials, &c., and on August 14th we agreed on Wilson, Rowe, McCoy, and Hearn.--On Feb. 17th I received the Prussian Order of Merit.--I had correspondence with the Treasury on the scale to be adopted for the Maps of the British Survey. I proposed 1/3000, and for some purposes 1/600.--I printed a Paper on the Deluge, in which I shewed (I believe to certainty) that the Deluge of Genesis was merely a Destructive Flood of the Nile.--Being well acquainted with