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

travaux de votre observatoire, et surtout de ce que l'on aura fait pour l'observation du passage de Venus et la determination exacte de la passage.

J'ai recu deja les Proceedings de la Royal Society lesquels m'interessent vivement.

Je voudrais vous ecrire dans votre langue, mais, comme je n'en ai pas l'habitude, j'ai craigne de ne pas vous exprimer tout-a-fait les sentiments de

Votre affectionne,
D. PEDRO D'ALCANTARA.

RIO,
22 Octobre, 1872 .

* * * * *

Airy's reply was as follows:

ROYAL OBSERVATORY, GREENWICH,
1872, November 26 .

SIRE,

I am honoured with your Imperial Majesty's autograph letter of October 22 informing me that, on considering the attention which the Royal Society of London had been able to offer to your Majesty, as well as the explanation of the various parts of the establishment of this Observatory which I had the honor and the high gratification to communicate, You had been pleased to place my name in the Imperial Order of the Rose, and to present to me the Decorations of Grand Cross of that Order.

With pride I receive this proof of Your Majesty's recollection of your visit to the scientific institutions of Great Britain.

The Diploma of the appointment to the Order of the Rose, under the Imperial Sign Manual, together with the Decorations of the Order, have been transmitted to me by his Excellency Don Pereira de Andrada, Your Majesty's Representative at the British Court.

Your Majesty has been pleased to advert to the approaching Transit of Venus, on the preparations for which you found me engaged. It is unfortunate that the Transit of 1874 will not be visible at Rio de Janeiro. For that of 1882, Rio will be a favourable position, and we reckon on the observations to be made there. Your Majesty may be assured that I shall loyally bear in mind your desire to be informed of any remarkable enterprise of this Observatory, or of any principal step in the preparations for the Transit of Venus and of its results.

I have the honor to be
Sire,
Your Imperial Majesty's very faithful servant,
G.B. AIRY.

To His Majesty
The Emperor of Brazil.

* * * * *

Airy's old friend, Adam Sedgwick, was now very aged and infirm, but his spirit was still vigorous, and he was warm-hearted as ever. The following letter from him (probably the last of their long correspondence) was written in this year, and appears characteristic:


TRINITY COLLEGE, CAMBRIDGE,
May 10, 1872 .

MY DEAR AIRY,

I have received your card of invitation for the 1st of June, and with great joy should I count upon that day if I thought that I should be able to accept your invitation: but alas I have no hope of the kind, for that humiliating malady which now has fastened upon me for a full year and a half has not let go its hold, nor is it likely to do so. A man who is journeying in the 88th year of his pilgrimage is not likely to throw off such a chronic malady. Indeed were I well enough to come I am deaf as a post and half blind, and if I were with you I should only be able to play dummy. Several years have passed away since I was last at your Visitation and I had great joy in seeing Mrs Airy and some lady friends at the Observatory, but I could not then attend the dinner. At that Meeting were many faces that I knew, but strangely altered by the rude handling of old Time, and there were many new faces which I had never seen before at a Royal Society Meeting; but worse than all, all the old faces were away. In vain I looked round for Wollaston, Davy, Davies Gilbert, Barrow, Troughton, &c. &c.; and the merry companion Admiral Smyth was also away, so that my last visit had its sorrowful side. But why should I bother you with these old man's mopings.

I send an old man's blessing and an old man's love to all the members of your family; especially to Mrs Airy, the oldest and dearest of my lady friends.

I remain, my dear Airy,
Your true-hearted old friend,
his
ADAM X SEDGWICK.
mark

P.S. Shall I ever again gaze with wonder and delight from the great window of your Observatory.

The body of the above letter is in the handwriting of an amanuensis, but the signature and Postscript are in Sedgwick's handwriting. (Ed.)

* * * * *


1873

"Chronographic registration having been established at the Paris Observatory, Mr Hilgard, principal officer of the American Coast Survey, has made use of it for determining the longitude of Harvard from Greenwich, through Paris, Brest, and St Pierre. For this purpose Mr Hilgard's Transit Instrument was planted in the Magnetic Court. I understand that the result does not sensibly differ from that obtained by Mr Gould, through Valentia and Newfoundland.--It was known to the scientific world that several of the original thermometers, constructed by Mr Sheepshanks (in the course of his preparation of the National Standard of Length) by independent calibration of the bores, and independent determination of the freezing and boiling points on arbitrary graduations, were still preserved at the Royal Observatory. It was lately stated to me by M. Tresca, the principal officer of the International Metrical Commission, that, in the late unhappy war in Paris, the French original thermometers were destroyed; and M. Tresca requested that, if possible, some of the original thermometers made by Mr Sheepshanks might be appropriated to the use of the International Commission. I have therefore transferred to M. Tresca the three thermometers A.6, S.1, S.2, with the documentary information relating to them, which was found in Mr Sheepshanks's papers; retaining six thermometers of the same class in the Royal Observatory.--The Sidereal Standard Clock continues to give great satisfaction. I am considering (with the aid of Mr Buckney, of the firm of E. Dent and Co.) an arrangement for barometric correction, founded on the principle of action on the pendulum by means of a magnet which can be raised or lowered by the agency of a large barometer.--The Altazimuth has received some important alterations. An examination of the results of observations had made me dissatisfied with the bearings of the horizontal pivots in their Y's. Mr Simms, at my request, changed the bearings in Y's for bearing in segments of circles, a construction which has worked admirably well in the pivots of the Transit Circle." (And in various other respects the instrument appears to have received a thorough overhauling. Ed.)--"With the consent of the Royal Society and of the Kew Committee, the Kew Heliograph has been planted in the new dome looking over the South Ground. It is not yet finally adjusted.--Some magnetic observations in the Britannia and Conway tubular bridges were made last autumn. For this purpose I detached an Assistant (Mr Carpenter), who was aided by Capt. Tupman, R.M.A.; in other respects the enterprise was private and at private expense.--The rates of the first six chronometers (in the annual trials) are published, in a form which appears most likely to lead to examination of the causes that influence their merits or demerits. This report is extensively distributed to British and Foreign horologists and instrument-makers. All these artists appear to entertain the conviction that the careful comparisons made at this Observatory, and the orderly form of their publication, have contributed powerfully to the improvement of chronometers.--Very lately, application has been made to me, through the Board of Trade, for plans and other information regarding time-signal-balls, to assist in guiding the authorities of the German Empire in the establishment of time signals at various ports of that State. In other foreign countries the system is extending, and is referred to Greenwich as its origin.--The arrangements and preparations for the observation of the Transit of Venus occupied much attention. With regard to the photoheliographs it is proposed to make trial of a plan proposed by M. Janssen, for numerous photographs of Venus when very near to the Sun's limb. On Apr. 26th the engaging of photographic teachers was sanctioned. Observers were selected and engaged. A working model of the Transit was prepared, and the use of De La Rue's Scale was practised. There was some hostile criticism of the stations selected for the observation of the Transit, which necessitated a formal reply.--Reference is made to the increase of facilities for making magnetical and meteorological observations. The inevitable result of it is, that observations are produced in numbers so great that complete reduction becomes almost impossible. The labour of reduction is very great, and it is concluded that, of the enormous number of meteorological observations now made at numerous observatories, very few can ever possess the smallest utility.--Referring to my Numerical Lunar Theory: on June 30th, 1873, a theory was formed, nearly but not perfectly complete. Numerical development of powers of a/r and r/a. Factors of corrections to Delaunay first attempted, but entirely in numerical form."--In March of this