AT GREENWICH OBSERVATORY FROM JANUARY 1ST, 1876,
TO HIS RESIGNATION OF OFFICE ON AUGUST 15TH,
1881.
1876
"At the door from the Front Court to the staircase of the Octagon Room
(the original entrance to the Observatory as erected by Sir
Christopher Wren), a small porch-shelter has been often desired. I
proposed to fix there a fan-roof of quadrantal form, covering the
upper flat stone of the external steps.--On a critical examination of
the micrometer-screws of the Transit Circle it was found that the
corrections, which range from -1°38" to +0°76", indicate considerable
wear in the screws; and it was found that as much as one-hundreth part
of an inch had been worn away from some of the threads. The old screws
were consequently discarded, and new ones were made by Mr Simms.--The
adjustment of the Spectroscope has occupied a great deal of
attention. There was astigmatism of the prisms; and false light
reflected from the base of the prisms, causing loss both of light and
of definition. The latter defect was corrected by altering the angles,
and then astigmatism was corrected by a cylindrical lens near the
slit. The definition in both planes was then found to be perfect.--The
number of small planets has now become so great, and the interest of
establishing the elements of all their orbits so small,--while at the
same time the light of all those lately discovered is very faint, and
the difficulty and doubt of observation greatly increased,--that I
have begun to think seriously of limiting future observations to a
small number of these objects.--All observations with the Spectroscope
have been completely reduced; the measures of lines in the spectra of
elements being converted into corresponding wave-lengths, and the
observations of displacement of lines in the spectra of stars being
reduced so as to exhibit the concluded motion in miles per second,
after applying a correction for the earth's motion. Sixteen measures
of the F line in the spectrum of the Moon as compared with hydrogen
give a displacement corresponding to a motion of less than two miles a
second, which seems to shew that the method of comparison now adopted
is free from systematic error; and this is supported by the manner in
which motions of approach and recession are distributed among the
stars examined on each night of observation. The results recently
obtained appear to be on the whole as consistent as can be expected in
such delicate observations, and they support in a remarkable manner
the conclusions of Dr Huggins, with regard to the motions of those
stars which he examined.--Photographs of the sun have been taken with
the photoheliograph on 182 days. On one of the photographs, which was
accidentally exposed while the drop slit was being drawn up, there
appears to be a faint image of a cloud-like prominence close to the
sun's limb, though the exposure probably only amounted to a fraction
of a second. A prominence of unusual brilliancy was seen with the
Spectroscope about the same time and in the same position with
reference to the Sun's limb. All groups of Sun-spots and faculae have
been numbered, and the dates of their first and last appearances
entered up to the present time. Areas of spots have been measured, and
the measures have been reduced to millionths of the Sun's visible
hemisphere.--The examination of the readings of the deep-sunk
thermometers from 1846 to 1873 has exhibited some laws which had been
sufficiently established before this time, and some which were less
known. Among the former were the successive retardations of seasons
in successive descents, amounting to about four months at the depth of
25 feet; and the successive diminutions of the annual range of
temperature. Among the latter is the character of the changes from
year to year, which the great length of this series of observations
brings well to light. It is found that from year to year the mean
temperature of the surface for the year, varying by three or four
degrees of Fahrenheit, follows in its changes the mean temperature of
the atmosphere for the year, and that the changes of annual
temperature are propagated downwards, retarded in phase and
diminishing in amount of change, in the same manner (though probably
not following the same law) as the season changes. The inference from
this is, that changes of temperature come entirely from the exterior
and in no discoverable degree from the interior; an inference which
may be important in regard both to solar action and to geology.
--Referring to the Transit of Venus observations: In the
astronomical part of the reductions, there has been great labour and
difficulty in the determination of local sidereal times; some books of
observations required extensive transcription; some instrumental
errors are still uncertain; the latter determinations have perplexed
us so much that we are inclined to believe that, in spite of the great
facilities of reduction given by the transit instrument, it would be
better to rely on the altazimuth for time-determinations.... In the
photographic part, I have confined my attention entirely to measures
of the distance between the centres of the Sun and Planet, a
troublesome and complex operation.--Referring to the progress of the
Numerical Lunar Theory: With a repetition of grant from the Treasury,
I have usually maintained four junior computers on this work. The
progress, though considerable, has not been so great as I had hoped,
by reason of the excessive personal pressure upon me during the whole
year.--I wrote a letter of congratulation to Le Verrier on the
completion of his great work of Planetary Tables.--On May 13th the
Queen was at South Kensington, and I attended to explain the
astronomical instruments, and shewed Her Majesty one of the Transit of
Venus photographs."
Of private history: He returned from his Playford visit on the 18th of
January.--In April there was a two-day trip to Colchester.--From June
13th to July 12th he was travelling in the North of Scotland and the
Orkneys with his daughters, staying for a short time with Mr Webster,
M.P., at Aberdeen, and with Mr Newall at Newcastle.--In September
there was a week's run to Birkenhead and Keswick.--In November a
week's run to Playford.--From the 13th to 15th of December he was at
Cambridge, and on the 28th he went to Playford for the usual winter
stay there.
1877
"In April of this year I was much engaged on the subject of Mr Gill's
expedition to Ascension to observe for the determination of the
parallax of Mars at the approaching opposition of that planet.--A
large Direct-vision Spectroscope has been quite recently made by Mr
Hilger under Mr Christie's direction on a new plan, in which either
great dispersion or great purity of spectrum is obtained by the use of
'Half-prisms,' according as the incident pencil falls first on the
perpendicular or on the oblique face. In this Spectroscope either one
or two half prisms can be used at pleasure, according to the
dispersion required, and there is facility for increasing the train to
three or four half-prisms, though the dispersion with two only is
nearly double of that given by the large ten-prism Spectroscope. The
definition in this form of Spectroscope appears to be very fine.--At
the end of May 1876, spectroscopic determinations of the Sun's
rotation were made by observations of the relative displacement of the
Fraunhofer lines at the east and west limbs respectively. The results
are in close agreement with the value of the rotation found from
observations of Sun-spots. A similar determination has also been made
in the case of Jupiter, with equally satisfactory results.--An
Electrometer on Sir William Thomson's plan, for continuous
photographic registration of atmospheric electricity has been received
from Mr White of Glasgow. It was mounted in December.--The computation
of the photographic records of the barometer from 1854 to 1873 has so
far advanced that we can assert positively that there is no trace of
lunar tide in the atmosphere; but that there is a strongly marked
semi-diurnal solar tide, accompanied with a smaller diurnal tide. We
are at present engaged in comparing the barometric measures with the
directions of the wind.--Regarding the distribution of the printed
observations: There is no extensive wish for separate magnetic
observations, but general magnetic results are in great demand,
especially for mining operations, and to meet this a map of magnetic
declination is furnished in the newspaper called the 'Colliery
Guardian.'--As regards the operations for the Transit of Venus: The
computing staff has by degrees been reduced to two junior computers
within the Observatory; and one or two computers external to the
Observatory, who are employed on large groups of systematic
calculations. The principal part of the calculations remaining at the
date of the last Report was that applying to the determination of the
geographical longitudes of fundamental stations. At the moment of my
writing, the last of these (the longitude of Observatory Bay,
Kerguelen) is not absolutely finished:... The method of determining
the geographical longitude of the principal station in each group by
vertical transits of the Moon has been found very successful at
Honolulu and Rodriguez. For stations in high south latitude,
horizontal transits are preferable.--As regards the Numerical Lunar
Theory: With the view of preserving, against the ordinary chances of
destruction or abandonment, a work which is already one of
considerable magnitude, I have prepared and have printed as Appendix
to the Greenwich Observations (with additional copies as for a
separate work) the ordinary Equations of Lunar Disturbance, the novel
theory of Symbolical Variations, and the Numerical Developments of the
quantities on the first side of the Equations.--At various times from
February to May I was engaged on the reduction of Malta Tides, and on
a Paper concerning the same.--In July I was awarded the Albert Medal
for my Compass corrections, and received the same from the Prince of
Wales.--In February, Campbell's instrument for the registration of
sunshine was introduced: it was mounted in July."
Of private history: "I was at Playford until Jan. 19th, in close
correspondence as usual with Mr Christie at the Observatory, and
attending to my Numerical Lunar Theory.--From Mar. 29th to Apr. 2nd I
went on a short trip to Hereford, Worcester, &c.--From June 8th to
20th I was at Playford.--From Aug. 13th to Sept. 8th Airy was on an
expedition in Ireland, chiefly in the North and West, with his
daughters. When at Dublin he visited Grubb's instrument factory. On
the return journey he stayed for some time in the Lake District of
Cumberland, and took soundings in the neighbourhood of the place of
the 'floating island' in Derwentwater."
Airy took the greatest interest in antiquarian matters, whether
military or ecclesiastical, and his feelings on such matters is well
illustrated by the following letter:
ROYAL OBSERVATORY, GREENWICH, S.E.
_1877, February 27_.
DEAR SIR,
I venture to ask if you can assist me in the following matter.
In the Parish Church of Playford, near Ipswich, Suffolk, was a
splendid brass tombstone to Sir Thomas Felbrigg. By an act of folly
and barbarism, almost unequalled in the history of the world, the
Incumbent and Curate nearly destroyed the brass inscription
surrounding the image of the Knight.
This tombstone is figured in Gough's Sepulchral Antiquities, which, I
presume, is to be found in the British Museum.
And I take the liberty to ask if you would kindly look at the
engraving, and give me any suggestion as to the way in which some
copies of it could be made, in a fairly durable form. I am connected
with the parish of Playford, and am anxious to preserve for it this
memorial of a family of high rank formerly resident there.
I am, dear Sir,
Very faithfully yours,
G.B. AIRY.
_T. Winter Jones, Esq._
To this request Mr Winter Jones immediately acceded, and the engraving
was duly photographed, and copies were circulated with a historical
notice of Sir George (not Sir Thomas) Felbrigg and a history of the
Monument. Sir George Felbrigg was Esquire-at-Arms to Edward III., and
Lord of the Manor of Playford: he died in 1400, and was buried in the
North wall of Playford Church.
1878
The Report to the Board of Visitors has this paragraph: "I continue to
remark the approaching necessity for Library extension. Without having
absolutely decided on a site, I may suggest that I should wish to
erect a brick building, about 50 feet by 20, consisting of two very
low stories (or rather of one story with a gallery running round its
walls), so low that books can be moved by hand without necessity for a
ladder.--In the month of December, 1877, the azimuthal error of the
Transit Circle had increased to 10". A skilful workman, instructed by
Mr Simms, easily reduced the error to about 2".5 (which would leave
its mean error nearly 0), the western Y being moved to the north so
far as to reduce the reading of the transit micrometer, when pointed
to the south, from 35r.500 to 35r.000. The level error was not
sensibly affected.--The Sidereal Standard Clock preserves a rate
approaching to perfection, so long as it is left without disturbance
of the galvanic-contact springs (touched by its pendulum), which
transmit signals at every second of time to sympathetic clocks and the
chronograph. A readjustment of these springs usually disturbs the
rate.--To facilitate the observations of stars, a new working
catalogue has been prepared, in which are included all stars down to
the third magnitude, stars down to the fifth magnitude which have not
been observed in the last two catalogues, and a list of 258 stars of
about the sixth magnitude of which the places are required for the
United States Coast Survey. The whole number of stars in our new
working list is about 2500. It may be here mentioned that an extensive
series of observations was made, during the autumn, of about 70 stars,
at the request of Mr Gill, for comparison with Mars, Ariadne, and
Melpomene.--On Apr. 10th last, a very heavy fall of rain took
place. Between Apr. 10d. 5h. and Apr. 11d. 2h., 2.824 inch. was
recorded, and 75 per cent. of this, or 2.12 inch., fell in the eight
hours between 13-1/2h. and 21-1/2h.; and on May 7, 1 inch of rain fell
in 50 minutes, of which 1/2 inch fell in 15 minutes.--The
supplementary compensation continues to be applied with success to
Government chronometers which offer facilities for its introduction,
and a marked improvement in the performance of chronometers returned
after repair by the makers appears to have resulted from the increased
attention now given to the compensation. Of the 29 competitive
chronometers, 25 have the supplementary compensation."--With regard to
the reduction of the observations of the Transit of Venus: After
reference to the difficulties arising from the errors and the
interpretation of the language used by some of the observers, the
Report continues thus: "Finally a Report was made to the Government on
July 5th, giving as the mean result for Mean Solar Parallax 8".76; the
results from ingress and from egress, however, differing to the extent
of 0".11.... After further examination and consideration, the result
for parallax has been increased to 8".82 or 8".83. The results from
photography have disappointed me much. The failure has arisen, perhaps
sometimes from irregularity of limb, or from atmospheric distortion,
but more frequently from faintness and from want of clear
definition. Many photographs, which to the eye appeared good, lost all
strength and sharpness when placed under the measuring microscope. A
final result 8".17 was obtained from Mr Burton's measures, and 8".08
from Capt. Tupman's.--With regard to the Numerical Lunar Theory: A
cursory collection of the terms relating to the Areas (in the
Ecliptic) led me to suppose that there might be some error in the
computations of the Annual Equation and related terms. A most jealous
re-examination has however detected nothing, and has confirmed my
belief in the general accuracy of the numerical computations. I dare
not yet venture to assume an error in Delaunay's theory; but I
remember that the Annual Equation gave great trouble to the late Sir
John Lubbock, and that he more than once changed his conclusions as to
its true value.--In February I was engaged on the drawings and
preparations for my intended Lecture at Cockermouth on the probable
condition of the interior of the Earth. The Lecture was delivered in
April.--At different times in the autumn I was engaged on diagrams to
illustrate the passage of rays through eye-pieces and double-image
micrometers.--The miscellaneous scientific correspondence, which was
always going on, was in this year unusually varied and heavy."
Of private history: He was at Playford till Jan. 26th.--In April he
went to Cockermouth to deliver his Lecture above-mentioned: the
journey was by Birmingham, where he stayed for two days (probably with
his son Osmund, who resided there), to Tarn Bank (the residence of
Isaac Fletcher, M.P.): the lecture was delivered on the 22nd: he made
excursions to Thirlmere and Barrow, and to Edward I.'s Monument, and
returned to Greenwich on the 27th.--From June 17th to 28th he was at
Playford.--From Aug. 19th to Sept. 17th he was travelling in Scotland,
visiting the Tay Bridge, the Loch Katrine Waterworks, &c., and spent
the last fortnight of his trip at Portinscale, near Keswick. On
Dec. 23rd he went to Playford.
1879
"The manuscripts of every kind, which are accumulated in the ordinary
transactions of the Observatory, are preserved with the same care and
arranged on the same system as heretofore. The total number of bound
volumes exceeds 4000. Besides these there is the great mass of Transit
of Venus reductions and manuscripts, which when bound may be expected
to form about 200 volumes.--With regard to the numerous group of Minor
Planets, the Berlin authorities have most kindly given attention to my
representation, and we have now a most admirable and comprehensive
Ephemeris. But the extreme faintness of the majority of these bodies
places them practically beyond the reach of our meridian instrument,
and the difficulty of observation is in many cases further increased
by the large errors of the predicted places.--After a fine autumn, the
weather in the past winter and spring has been remarkably bad. More
than an entire lunation was lost with the Transit Circle, no
observation of the Moon on the meridian having been possible between
January 8 and March 1, a period of more than seven weeks. Neither Sun
nor stars were visible for eleven days, during which period the
clock-times were carried on entirely by the preceding rate of the
clock. The accumulated error at the end of this time did not exceed
0s'3.--Some difficulty was at first experienced with the Thomson
Electrometer, which was traced to want of insulation. This has been
mastered by the use of glass supporters, which carry some sulphuric
acid. The instrument is now in excellent order, and the photographic
registers have been perfectly satisfactory since 1879, February, when
the new insulators were applied.--From the annual curves of diurnal
inequality, deduced from the Magnetic Reductions, most important
inferences may be drawn, as to the connection between magnetic
phenomena and sun-spots. These annual curves shew a well-marked
change in close correspondence with the number of sun-spots. About the
epoch of maximum of sun-spots they are large and nearly circular,
having the same character as the curves for the summer months; whilst
about the time of sun-spot minimum they are small and
lemniscate-shaped, with a striking resemblance to the curves for the
winter months. The connection between changes of terrestrial magnetism
and sun-spots is shewn in a still more striking manner by a comparison
which Mr Ellis has made between the monthly means of the diurnal range
of declination and horizontal force, and Dr R. Wolf's 'relative
numbers' for frequency of sun-spots.--The records of sunshine with
Campbell's Registering Sun-dial are preserved in a form easily
accessible for reference, and the results are communicated weekly to
the Agricultural Gazette.--Prof. Oppolzer's results for the
determination of the longitudes of Vienna and Berlin, made in 1877,
have now been made public. They shew a remarkable agreement of the
Chronometric determination formerly made with the Telegraphic. It may
be of interest to recall the fact that a similar agreement was found
between the Chronometric and Telegraphic determinations of the
longitude of Valentia.--For observing the Transit of Venus of 1882,
the general impression appears to be that it will be best to confine
our observations to simple telescopic observations or micrometer
observations at Ingress and Egress, if possible at places whose
longitudes are known. For the first phenomenon (accelerated ingress)
the choice of stations is not good; but for the other phenomena
(retarded ingress, accelerated egress, retarded egress) there appears
to be no difficulty.--With regard to the Numerical Lunar Theory:
Respecting the discordance of Annual Equation, I suspend my
judgment. I have now discussed the theory completely; and in going
into details of secular changes, I am at this time engaged on that
which is the foundation of all, namely, the change of excentricity of
the Solar Orbit, and its result in producing Lunar Acceleration. An
important error in the theoretical formulae for Variations of Radius
Vector, Longitude, and Latitude, was discovered; some calculations
depending on them are cancelled."--Referring to the magnitude of the
printed volume of "Greenwich Observations," and the practicability of
reducing the extent of it, the Report states thus: "The tendency of
external scientific movement is to give great attention to the
phenomena of the Solar disc (in which this Observatory ought
undoubtedly to bear its part). And I personally am most unwilling to
recede from the existing course of magnetical and meteorological
observations....The general tendency of these considerations is to
increase the annual expenses of the Observatory. And so it has been,
almost continuously, for the last 42 years. The annual ordinary
expenses are now between 2-1/2 and 3 times as great as in my first
years at the Royal Observatory.--Mr Gill was appointed to the Cape
Observatory, and I wrote out instructions for him in March: there was
subsequently much correspondence respecting the equipment and repairs
of the Cape Observatory."--In the Monthly Notices of the Royal
Astronomical Society for January an article had appeared headed "Notes
on the late Admiral Smyth's Cycle of Celestial Objects, Vol. II." by
Mr Herbert Sadler. In this article Mr Sadler had criticized the work
of Admiral Smyth in a manner which Airy regarded as imputing bad faith
to Admiral Smyth. He at once took up the defence of his old friend
very warmly, and proposed certain Drafts of Resolutions to the Council
of the Society. These Resolutions were moved, but were amended or
negatived, and Airy immediately resigned his office of
Vice-President. There was considerable negociation on the subject, and
discussion with Lord Lindsay, and on May 9th Airy's Resolutions were
accepted by the Council.--In October Airy inspected the "Faraday"
telegraph ship, then lying in the river near Messrs Siemens' works,
and broke his finger by a fall on board the vessel.--In this year Airy
wrote and circulated a letter to the Members of the Senate of the
University of Cambridge, on the subject of the Papers set in the
Smith's Prizes Examination. In this letter, as on former occasions, he
objected much to the large number of questions in "purely idle
algebra, arbitrary combinations of symbols, applicable to no further
purpose." And in particular he singled out for comment the following
question, which was one of those set, "Using the term circle as
extending to the case where the radius is a pure imaginary, it is
required to construct the common chord of two given circles." This
drew forth as usual a rejoinder from Prof. Cayley, who wrote
enclosing a solution of his problem, but not at all to Airy's
satisfaction, who replied as follows: "I am not so deeply plunged in
the mists of impossibles as to appreciate fully your explanation in
this instance, or to think that it is a good criterion for University
candidates."
Of private history: On Jan. 21st he returned from Playford.--On March
22nd he attended the funeral of his sister at Little Welnetham near
Bury St Edmunds: Miss Elizabeth Airy had lived with him at the
Observatory from shortly after his appointment.--For about a week at
the end of April he was visiting Matlock, Edensor, and Buxton.--From
June 14th to July 18th he was staying at Portinscale near Keswick.--He
was at Playford for two or three days in October, and went there again
on Dec. 23rd for his usual winter holiday.
The following letter, relating to the life of Thomas Clarkson, was
written to Dr Merivale, Dean of Ely, after reading the account in the
"Times" of October 10th of the unveiling of a statue of Clarkson near
Ware:
ROYAL OBSERVATORY, GREENWICH,
LONDON, S.E.
_1879, October 11_.
DEAR SIR,
Pardon my intrusion on you, in reference to a transaction which has
greatly interested me--the honour paid by you to the memory of Thomas
Clarkson. With very great pleasure I have heard of this step: and I
have also been much satisfied with the remarks on it in the "Times." I
well remember, in Clarkson's "History of the Abolition," which I read
some 60 years ago, the account of the circumstance, now commemorated
by you, which determined the action of his whole subsequent life.
It is not improbable that, among those who still remember Clarkson, my
acquaintance with him began at the earliest time of all. I knew him,
intimately, from the beginning of 1815 to his death. The family which
he represented must have occupied a very good position in society. I
have heard that he sold two good estates to defray the expenses which
he incurred in his personal labours for Abolition: and his brother was
Governor of Sierra Leone (I know not at what time appointed). Thomas
Clarkson was at St John's College; and, as I gather from circumstances
which I have heard him mention, must have been a rather gay man. He
kept a horse, and at one time kept two. He took Orders in the Church;
and on one occasion, in the course of his Abolition struggle, he
preached in a church. But he afterwards resolutely laid aside all
pretensions to the title of Minister of the Church, and never would
accept any title except as layman. He was, however, a very earnest
reader of theology during my acquaintance with him, and appeared to be
well acquainted with the Early Fathers.
The precise words in which was announced the subject for Prize Essay
in the University were "Anne liceat invitos in servitutem trahere."
After the first great victory on the slave trade question, he
established himself in a house on the bank of Ullswater. I have not
identified the place: from a view which he once shewed me I supposed
it to be near the bottom of the lake: but from an account of the storm
of wind which he encountered when walking with a lady over a pass, it
seemed to be in or near Patterdale. When the remains of a mountaineer,
who perished in Helvellyn (as described in Scott's well-known poem),
were discovered by a shepherd, it was to Mr Clarkson that the
intelligence was first brought.
He then lived at Bury St Edmunds. Mrs Clarkson was a lady of Bury. But
I cannot assign conjecturally any dates to his removals or his
marriage. His only son took his B.A. degree, I think, about 1817.
I think it was in 1814 that he began his occupation of Playford
Hall--a moated mansion near Ipswich, formerly of great importance
--where he lived as Gentleman Farmer, managing a farm leased
from the Marquis of Bristol, and occupying a good position among the
gentry of the county. A relative of mine, with whom I was most
intimately acquainted, lived in the same parish (where in defiance of
school rules I spent nearly half my time, to my great advantage as I
believe, and where I still retain a cottage for occasional residence),
and I enjoyed much of Mr Clarkson's notice. It was by his strong
advice that I was sent to Cambridge, and that Trinity College was
selected: he rode with me to Rev. Mr Rogers of Sproughton for
introductory examination; he introduced me to Rev. C. Musgrave
(subsequently of Halifax), accidentally doing duty at Grundisburgh,
who then introduced me to Sedgwick, Peacock, and T. Musgrave
(subsequently of York). In 1825, when I spent the summer at Keswick,
he introduced me to Southey and Wordsworth.
Mr Clarkson lived about thirty years at Playford Hall, and died there,
and lies interred with his wife, son, and grandson, in Playford
churchyard. I joined several friends in erecting a granite obelisk to
his memory in the same churchyard. His family is extinct: but a
daughter of his brother is living, first married to T. Clarkson's son,
and now Mrs Dickinson, of the Rectory, Wolferton.
I am, my dear Sir,
Very faithfully yours,
G.B. AIRY.
_The Very Reverend,
The Dean of Ely._
1880
"The Admiralty, on final consideration of the estimates, decided not
to proceed with the erection of a new Library near the Magnetic
Observatory in the present year. In the mean time the space has been
cleared for the erection of a building 50 by 20 feet.--I have removed
the Electrometer Mast (a source of some expense and some danger), the
perfect success of Sir William Thomson's Electrometer rendering all
further apparatus for the same purpose unnecessary.--Many years ago a
double-image micrometer, in which the images were formed by the double
refraction of a sphere of quartz, was prepared by Mr Dollond for
Capt. Smyth, R.N. Adopting the same principle on a larger scale, I
have had constructed by Mr Hilger a micrometer with double refraction
of a sphere of Iceland spar. Marks have been prepared for examination
of the scale, but I have not yet had opportunity of trying it.--The
spectroscopic determination of Star-motions has been steadily
pursued. The stars are taken from a working list of 150 stars, which
may eventually be extended to include all stars down to the fourth
magnitude, and it is expected that in the course of time the motions
of about 300 stars may be spectroscopically determined.--A new
pressure-plate with springs has been applied by Mr Browning to Osler's
Anemometer, and it is proposed to make such modification as will give
a scale extending to 50 lbs. pressure on the square foot. Other parts
of the instrument have also been renewed.--As regards the reduction of
the magnetical results since 1863: In the study of the forms of the
individual curves; their relations to the hour, the month, the year;
their connection with solar or meteorological facts; the conjectural
physico-mechanical causes by which they are produced; there is much to
occupy the mind. I regret that, though in contemplation of these
curves I have remarked some singular (but imperfect) laws, I have not
been able to pursue them.--The mean temperature of the year 1879 was
46.1°, being 3.3° below the average of the preceding 38 years. The
highest temperature was 80.6° on July 30, and the lowest 13.7° on
Dec. 7. The mean temperature was below the average in every month of
the year; the months of greatest deviation being January and December,
respectively 6.8° and 7.6° below the average; the months of April,
May, July, and November were each between 4° and 5° below the average.
The number of hours of bright sunshine, recorded with Campbell's
Sunshine Instrument, during 1879, was only 983.--In the summer of 1879
Commander Green, U.S.N., came over to this country for the purpose of
determining telegraphically the longitude of Lisbon, as part of a
chain of longitudes extending from South America to Greenwich. A
successful interchange of signals was made with Commander Green
between Greenwich and Porthcurno on four nights, 1879, June 25 to
29. The results communicated by Commander Green shew that the
longitude of Lisbon Observatory, as adopted in the Nautical Almanac,
requires the large correction of +8.54".--With regard to the coming
Transit of Venus in 1882: From the facility with which the
requirements for geographical position are satisfied, and from the
rapid and accurate communication of time now given by electric
telegraph, the observation of this Transit will be comparatively easy
and inexpensive. I have attached greater importance than I did
formerly to the elevation of the Sun.... I remark that it is highly
desirable that steps be taken now for determining by telegraph the
longitude of some point of Australia. I have stated as the general
opinion that it will be useless to repeat photographic observations.
--In April Mr Barlow called, in reference to the Enquiry on
the Tay Bridge Disaster. (The Bridge had been blown down on
Dec. 28th, 1879.) I prepared a memorandum on the subject for the Tay
Bridge Commission, and gave evidence in a Committee Room of the House
of Lords on Apr. 29th." (Much of the Astronomer Royal's evidence on
this occasion had reference to the opinions which he had expressed
concerning the wind-pressure which might be expected on the projected
Forth Bridge, in 1873.)--In May Airy was consulted by the
Postmaster-General in the matter of a dispute which had arisen between
the Post Office and the Telephone Companies, which latter were alleged
to have infringed the monopoly of the Post Office in commercial
telegraphs: Airy made a declaration on the subject.--In July Mr
Bakhuyzen came to England to determine the longitude of Leyden, on
which he was engaged till Sept. 9th, and carried on his observations
at the Observatory.--In July Airy was much engaged in perusing the
records of Mr Gill's work at the Cape of Good Hope.
Of private history: On Jan. 24th he returned from Playford.--From June
14th to July 4th he was again at Playford.--From September 21st to
October 20th he was staying at Portinscale near Keswick.--On Dec. 23rd
he went again to Playford for his winter holiday.
Respecting the agitation at Cambridge for granting University degrees
to women, the following extract from a letter addressed to a young
lady who had forwarded a Memorial on the subject for his
consideration, and dated Nov. 10th, 1880, contains Airy's views on
this matter.
"I have not signed the Memorial which you sent for my consideration:
and I will endeavour to tell you why. I entirely approve of education
of young women to a higher pitch than they do commonly reach. I think
that they can successfully advance so far as to be able clearly to
understand--with gratification to themselves and with advantage to
those whose education they will superintend--much of the results of
the highest class of science which have been obtained by men whose
lives are in great measure devoted to it. But I do not think that
their nature or their employments will permit of their mastering the
_severe_ steps of beginning (and indeed all through) and the
_complicated_ steps at the end. And I think it well that this their
success should be well known--as it is sure to be--among their
relatives, their friends, their visitors, and all in whom they are
likely to take interest. Their connection with such a place as Girton
College is I think sufficient to lead to this. But I desire above all
that all this be done in entire subservience to what I regard as
_infinitely_ more valuable than any amount of knowledge, namely the
delicacy of woman's character. And here, I think, our views totally
separate. I do not imagine that the University Degree would really
imply, as regards education, anything more than is known to all
persons (socially concerned in the happiness of the young woman) from
the less public testimonial of the able men who have the means of
knowing their merits. And thus it appears to me that the admission to
University Degree would simply mean a more extended publication of
their names. I dread this."
1881
"The new line of underground telegraph wires has been completed by the
officers of the General Post Office. The new route is down Croom's
Hill in Greenwich, and the result of this change, at least as regards
the earth-current wires, and probably as regards the other wires, has
not been satisfactory. It was soon found that the indications of the
earth-current wires were disturbed by a continual series of petty
fluctuations which almost completely masked the proper features of
earth currents.... If this fault cannot be removed, I should propose
to return to our original system of independent wires (formerly to
Croydon and Dartford).--The new Azimuth-mark (for the Altazimuth),
upon the parapet of the Naval College, is found to be perfectly
satisfactory as regards both steadiness and visibility. The
observations of a low star for zero of azimuth have been omitted since
the beginning of 1881; the mark, in combination with a high star,
appearing to give all that is necessary for this purpose.--All the
instruments have suffered from the congealing of the oil during the
severe weather of the past winter, and very thorough cleaning of all
the moving parts has been necessary.--The Solar Eclipse of 1880,
Dec. 31, was well observed. The first contact was observed by four
observers and the last contact by two. The computations for the
observations have been exceptionally heavy, from the circumstance that
the Sun was very low (86° 14' Z.D. at the last observation) and that
it has therefore been necessary to compute the refraction with great
accuracy, involving the calculation of the zenith distance for every
observation. And besides this, eighty-six separate computations of the
tabular R.A. and N.P.D. of cusps have been required.--Amongst other
interesting spectroscopic observations of the Sun, a remarkable
spectrum of a sun-spot shewing 17 strong black lines or bands, each as
broad as b_1, in the solar spectrum, was observed on 1880, Nov. 27 and
29. These bands to which there is nothing corresponding in the Solar
Spectrum (except some very faint lines) have also been subsequently
remarked in the spectrum of several spots.--The Police Ship 'Royalist'
(which was injured by a collision in 1879 and had been laid up in
dock) has not been again moored in the river, and the series of
observations of the temperature of the Thames is thus terminated.
--Part of the month of January 1881 was, as regards cold,
especially severe. The mean temperature of the period January 12 to
26 (15 days) was only 24.2°, or 14.7° below the average; the
temperature fell below 20° on 10 days, and rose above the freezing
point only on 3 days. The highest temperature in this period was
35.3°, the lowest 12.7°. On January 17th (while staying at Playford)
my son Hubert and I noticed an almost imperceptible movement in the
upper clouds from the South-East. On that night began the terrible
easterly gale, accompanied with much snow, which lasted to the night
of the 18th. The limiting pressure of 50 lbs. on the square foot of
Osler's Anemometer was twice exceeded during this storm.--With respect
to the Diurnal Inequalities of Magnetic Horizontal Force: Assuming it
to be certain that they originate from the Sun's power, not
immediately, but mediately through his action on the Earth, it appears
to me (as I suggested long ago) that they are the effects of the
attraction of the red end or north end of the needle by the heated
portions of our globe, especially by the heated sea, whose effect
appears to predominate greatly over that of the land. I do not say
that everything is thus made perfectly clear, but I think that the
leading phenomena may be thus explained. And this is almost
necessarily the way of beginning a science.--In the first few years
after the strict and systematic examination of competitive
chronometers, beginning with 1856, the accuracy of chronometers was
greatly increased. For many years past it has been nearly
stationary. I interpret this as shewing that the effects of bad
workmanship are almost eliminated, and that future improvement must be
sought in change of some points of construction.--Referring to the
Transit of Venus in 1874, the printing of all sections of the
Observations, with specimens of the printed forms employed, and
remarks on the photographic operations, is very nearly completed. An
Introduction is begun in manuscript. I am in correspondence with the
Commission which is entrusted with the arrangements for observation of
the Transit of 1882.--The Numerical Lunar Theory has been much
interrupted by the pressure of the Transit of Venus work and other
business."--In his Report to the Board of Visitors (his 46th and
last), Airy remarks that it would be a fitting opportunity for the
expression of his views on the general objects of the Observatory, and
on the duties which they impose on all who are actively concerned in
its conduct. And this he proceeds to do in very considerable
detail.--On May 5th he wrote to Lord Northbrook (First Lord of the
Admiralty) and to Mr Gladstone to resign his post of Astronomer
Royal. From time to time he was engaged on the subject of a house for
his future residence, and finally took a lease of the White House at
the top of Croom's Hill, just outside one of the gates of Greenwich
Park. On the 15th of August he formally resigned his office to Mr
W.H.M. Christie, who had been appointed to succeed him as Astronomer
Royal, and removed to the White House on the next day, August 16th.
His holiday movements in the portion of the year up to August 16th
consisted in his winter visit to Playford, from which he returned on
Jan. 24th: and a subsequent visit to Playford from June 7th to 18th.
* * * * *
The following correspondence relating to Airy's retirement from office
testifies in a remarkable manner to the estimation in which his
services were held, and to the good feeling which subsisted between
him and his official superiors.
10, DOWNING STREET, WHITEHALL,
_June 6, 1881_.
DEAR SIR GEORGE AIRY,
I cannot receive the announcement of your resignation, which you have
just conveyed to me, without expressing my strong sense of the
distinction you have conferred upon the office of Astronomer Royal,
and of the difficulty of supplying your place with a person of equal
eminence. Let me add the expression of my best wishes for the full
enjoyment of your retirement from responsibility.
I remain, dear Sir George Airy,
Faithfully yours,
W.E. GLADSTONE.
* * * * *
ADMIRALTY,
_June 10th, 1881_.
SIR,
I am commanded by my Lords Commissioners of the Admiralty to
acknowledge the receipt of your letter of the 4th instant, intimating
your desire to retire on the 15th August next from the office of
Astronomer Royal.
2. In reply I am to acquaint you that your wishes in this matter have
been communicated to the Prime Minister, and that the further
necessary official intimation will in due course be made to the
Treasury.
3. At the same time I am instructed by their Lordships to convey to
you the expression of their high appreciation of the remarkably able
and gifted manner, combined with unwearied diligence and devotion to
the Public Service (especially as regards the Department of the State
over which they preside), in which you have performed the duties of
Astronomer Royal throughout the long period of forty-five years.
4. I am further to add that their Lordships cannot allow the present
opportunity to pass without giving expression to their sense of the
loss which the Public Service must sustain by your retirement, and to
the hope that you may long enjoy the rest to which you are so justly
entitled.
I am, Sir,
Your obedient Servant,
ROBERT HALL.
_Sir G. B. Airy, K.C.B.
&c., &c.,
Royal Observatory, Greenwich._
* * * * *
ADMIRALTY,
_28th June, 1881_.
SIR,
My Lords Commissioners of the Admiralty have much pleasure in
transmitting copy of a resolution passed by the Board of Visitors of
the Royal Observatory on the 4th June last, bearing testimony to the
valuable services you have rendered to Astronomy, to Navigation, and
the allied Sciences throughout the long period during which you have
presided over the Royal Observatory.
I am, Sir,
Your obedient Servant,
ROBERT HALL.
_Sir George Biddell Airy, K.C.B.
&c., &c., &c.,
Royal Observatory, Greenwich._
"The Astronomer Royal (Sir George B. Airy) having announced his
intention of shortly retiring from his position at the Royal
Observatory, the following resolution proposed by Professor
J. C. Adams, and seconded by Professor G. G. Stokes, was then
unanimously adopted and ordered to be recorded in the Minutes of the
Proceedings.
"The Board having heard from the Astronomer Royal that he proposes to
terminate his connection with the Observatory on the 15th of August
next, desire to record in the most emphatic manner their sense of the
eminent services which he has rendered to Astronomy, to Navigation and
the allied Sciences, throughout the long period of 45 years during
which he has presided over the Royal Observatory.
"They consider that during that time he has not only maintained but
has greatly extended the ancient reputation of the Institution, and
they believe that the Astronomical and other work which has been
carried on in it under his direction will form an enduring monument of
his Scientific insight and his powers of organization.
"Among his many services to Science, the following are a few which
they desire especially to commemorate:
_(a)_ "The complete re-organization of the Equipment of the
Observatory.
_(b)_ "The designing of instruments of exceptional stability and
delicacy suitable for the increased accuracy of observation demanded
by the advance of Astronomy.
_(c)_ "The extension of the means of making observations of the Moon
in such portions of her orbit as are not accessible to the Transit
Circle.
_(d)_ "The investigation of the effect of the iron of ships upon
compasses and the correction of the errors thence arising.
_(e)_ "The Establishment at the Observatory and elsewhere of a System
of Time Signals since extensively developed by the Government.
"The Board feel it their duty to add that Sir George Airy has at all
times devoted himself in the most unsparing manner to the business of
the Observatory, and has watched over its interests with an assiduity
inspired by the strongest personal attachment to the Institution. He
has availed himself zealously of every scientific discovery and
invention which was in his judgment capable of adaptation to the work
of the Observatory; and the long series of his annual reports to the
Board of Visitors furnish abundant evidence, if such were needed, of
the soundness of his judgment in the appreciation of suggested
changes, and of his readiness to introduce improvements when the
proper time arrived. While maintaining the most remarkable punctuality
in the reduction and publication of the observations made under his
own superintendance, he had reduced, collected, and thus rendered
available for use by astronomers, the Lunar and Planetary Observations
of his predecessors. Nor can it be forgotten that, notwithstanding his
absorbing occupations, his advice and assistance have always been at
the disposal of Astronomers for any work of importance.
"To refer in detail to his labours in departments of Science not
directly connected with the Royal Observatory may seem to lie beyond
the province of the Board. But it cannot be improper to state that its
members are not unacquainted with the high estimation in which his
contributions to the Theory of Tides, to the undulatory theory of
Light, and to various abstract branches of Mathematics are held by men
of Science throughout the world.
"In conclusion the Board would express their earnest hope, that in his
retirement Sir George Airy may enjoy health and strength and that
leisure for which he has often expressed a desire to enable him not
only to complete the numerical Lunar Theory on which he has been
engaged for some years past, but also to advance Astronomical Science
in other directions."
* * * * *
ADMIRALTY,
_27th October, 1881_.
SIR,
I am commanded by my Lords Commissioners of the Admiralty to transmit
to you, herewith, a copy of a Treasury Minute, awarding you a Special
Pension of _£1100_ a year, in consideration of your long and brilliant
services as Astronomer Royal.
I am, Sir,
Your obedient Servant,
ROBERT HALL.
_Sir G.B. Airy, K.C.B., F.R.S., &c., &c.
The White House, Croom's Hill, Greenwich._
Copy of Treasury Minute, dated 10th October, 1881:
My Lords have before them a statement of the services of Sir George
Biddell Airy, K.C.B., F.R.S., who has resigned the appointment of
Astronomer Royal on the ground of age.
Sir George Airy has held his office since the year 1835, and has also,
during that period, undertaken various laborious works, demanding
scientific qualifications of the highest order, and not always such as
could strictly be said to be included among the duties of his office.
The salary of Sir G. Airy as Astronomer Royal is _£1200_ a year, in
addition to which he enjoys an official residence rent free, and,
under ordinary circumstances he would be entitled to a pension equal
to two-thirds of his salary and emoluments.
My Lords, however, in order to mark their strong sense of the
distinction which, during a long and brilliant career Sir George Airy
has conferred upon his office, and of the great services which, in
connection with, as well as in the discharge of, his duties, he has
rendered to the Crown and the Public, decide to deal with his case
under the IXth Section of the Superannuation Act, 1859, which empowers
them to grant a special pension for special services.
Accordingly my Lords are pleased to award to Sir George Biddell Airy,
K.C.B., F.R.S., a special Retired Allowance of _£1100_ per annum.
* * * * *
THE WHITE HOUSE,
CROOM'S HILL, GREENWICH,
_1881, October 29_.
SIR,
I have the honour to acknowledge your letter of October 27,
transmitting to me, by instruction of The Lords Commissioners of
Admiralty, copy of a Treasury Minute dated 1881 October 10, in which
the Lords Commissioners of Her Majesty's Treasury are pleased to award
to me an annual retired allowance of _£1100_ per annum.
Acknowledging the very liberal award of the Lords Commissioners of
Treasury, and the honourable and acceptable terms in which it is
announced, I take leave at the same time to offer to Their Lordships
of the Admiralty my recognition of Their Lordships' kindness and
courtesy in thus handing to me copy of the Treasury Minute.
I have the honour to be, Sir,
Your very obedient Servant,
G.B. AIRY.
_The Secretary of the Admiralty,_
* * * * *
From the Assistants of the Royal Observatory, with whom he was in
daily communication, whose faithful and laborious services he had so
often thankfully recognized in his Annual Reports to the Board of
Visitors, and to whom so much of the credit and success of the
Observatory was due, he received the following address:
ROYAL OBSERVATORY, GREENWICH,
_1881, August 11_.
DEAR SIR,
We cannot allow the official relation which has so long existed
between yourself and us to terminate without expressing to you our
sense of the admirable manner in which you have, in our opinion,
upheld the dignity of the office of Astronomer Royal during the many
years that you have occupied that important post.
Your long continued and varied scientific work has received such
universal recognition from astronomers in all lands, that it is
unnecessary for us to do more than assure you how heartily we join in
their appreciation of your labours. We may however add that our
position has given us opportunities of seeing that which others cannot
equally well know, the untiring energy and great industry which have
been therein displayed throughout a long and laborious career, an
energy which leads you in retirement, and at fourscore years of age,
to contemplate further scientific work.
We would ask you to carry with you into private life the best wishes
of each one of us for your future happiness, and that of your family,
expressing the hope that the days of retirement may not be few, and
assuring you that your name will long live in our remembrance.
We are, dear Sir,
Yours very faithfully,
W.H.M. CHRISTIE, EDWIN DUNKIN, WILLIAM
ELLIS, GEORGE STRICKLAND CRISWICK, W.
C. NASH, A.M.W. DOWNING, EDWARD W.
MAUNDER, W.G. THACKERAY, THOMAS LEWIS.
_Sir G.B. Airy, K.C.B., &c., &c.,
Astronomer Royal._
* * * * *
ROYAL OBSERVATORY, GREENWICH,
_1881, August 13_.
MY DEAR MR CHRISTIE,
and Gentlemen of the Royal Observatory,
With very great pleasure I have received your letter of August 11. I
thank you much for your recognition of the general success of the
Observatory, and of a portion of its conduct which--as you remark--can
scarcely be known except to those who are every day engaged in it: but
I thank you still more for the kind tone of your letter, which seems
to shew that the terms on which we have met are such as leaves, after
so many years' intercourse, no shadow of complaint on any side.
Reciprocating your wishes for a happy life, and in your case a
progressive and successful one,
I am,
My dear Mr Christie and Gentlemen,
Yours faithfully,
G.B. AIRY.
* * * * *
Throughout his tenure of office Airy had cultivated and maintained the
most friendly relations with foreign astronomers, to the great
advantage of the Observatory. Probably all of them, at one time or
another, had visited Greenwich, and to most of them he was well
known. On his retirement from office he received an illuminated
Address from his old friend Otto Struve and the staff of the Pulkowa
Observatory, an illuminated Address from the Vorstand of the
Astronomische Gesellschaft at Berlin signed by Dr Auwers and the
Secretaries, a complimentary letter from the Academy of Sciences at
Amsterdam, and friendly letters of sympathy from Dr Gould,
Prof. Newcombe, Dr Listing, and from many other scientific friends and
societies. His replies to the Russian and German Addresses were as
follows:
ROYAL OBSERVATORY, GREENWICH,
_1881, August 5_.
MY DEAR SIR,
I received, with feelings which I will not attempt to describe, the
Address of yourself and the Astronomers of Pulkowa generally, on the
occasion of my retirement from the office of Astronomer Royal. I can
scarcely credit myself with possessing all the varied claims to your
scientific regard which you detail. I must be permitted to attribute
many of them to the long and warm friendship which has subsisted so
long between the Directors of the Pulkowa Observatory and myself, and
which has influenced the feelings of the whole body of Astronomers
attached to that Institution. On one point, however, I willingly
accept your favourable expressions--I have not been sparing of my
personal labour--and to this I must attribute partial success on some
of the subjects to which you allude.
In glancing over the marginal list of scientific pursuits, I remark
with pleasure the reference to _Optics_. I still recur with delight to
the Undulatory Theory, once the branch of science on which I was best
known to the world, and which by calculations, writings, and lectures,
I supported against the Laplacian School. But the close of your
remarks touches me much more--the association of the name of W. Struve
and my own. I respected deeply the whole character of your Father, and
I believe that he had confidence in me. From our first meeting in 1830
(on a Commission for improvement of the Nautical Almanac) I never
ceased to regard him as superior to others. I may be permitted to add
that the delivery of his authority to the hands of his son has not
weakened the connection of myself with the Observatory of Poulkova.
Acknowledging gratefully your kindness, and that of all the
Astronomers of the Observatory of Poulkova, and requesting you to
convey to them this expression,
I am, my dear Sir,
Yours most truly,
G.B. AIRY.
_To M. Otto von Struve,
Director of the Observatory of Poulkova
and the Astronomers of that Observatory._
* * * * *
ROYAL OBSERVATORY, GREENWICH,
_1881, August 3_.
MY DEAR SIR,
With very great pleasure I received the Address of the Astronomische
Gesellschaft on occasion of my intended resignation of the Office of
Astronomer Royal: dated July 27, and signed by yourself as President
and Messrs Schoenfeld and Winnecke as Secretaries of the Astronomische
Gesellschaft. I thank you much for the delicacy of your arrangement
for the transmission of this document by the hands of our friend Dr
Huggins. And I think you will be gratified to learn that it arrived at
a moment when I was surrounded by my whole family assembled at my
_jour-de-fête_, and that it added greatly to the happiness of the
party.
I may perhaps permit myself to accept your kind recognition of my
devotion of time and thought to the interests of my Science and my
Office. It is full reward to me that they are so recognized. As to
the success or utility of these efforts, without presuming, myself, to
form an opinion, I acknowledge that the connection made by the
Astronomische Gesellschaft, between my name and the advance of modern
astronomy, is most flattering, and will always be remembered by me
with pride.
It is true, as is suggested in your Address, that one motive for my
resignation of Office was the desire to find myself more free for the
prosecution of further astronomical investigations. Should my health
remain unbroken, I hope to enter shortly upon this undertaking.
Again acknowledging the kindness of yourself and the Vorstand of the
Astronomische Gesellschaft, and offering my best wishes for the
continued success of that honourable institution,
I am, my dear Sir,
Yours very truly,
G.B. AIRY.
_To Dr Aimers
and the Vorstand of the
Astronomische Gesellschaft._