AT GREENWICH OBSERVATORY--1866 TO 1876.
1866
In this year the cube of the Transit Circle was pierced, to permit
reciprocal observations of the Collimators without raising the
instrument. This involved the construction of improved Collimators,
which formed the subject of a special Address to the Members of the
Board of Visitors on Oct. 21st 1865.--From the Report to the Visitors
it appears that "On May 23rd 1865, a thunderstorm of great violence
passed very close to the Observatory. After one flash of lightning, I
was convinced that the principal building was struck. Several
galvanometers in the Magnetic Basement were destroyed. Lately it has
been remarked that one of the old chimneys of the principal building
had been dislocated and slightly twisted, at a place where it was
surrounded by an iron stay-band led from the Telegraph Pole which was
planted upon the leads of the Octagon Room."--"On consideration of the
serious interruptions to which we have several times been exposed from
the destruction of our open-air Park-wires (through snow-storms and
gales), I have made an arrangement for leading the whole of our wires
in underground pipes as far as the Greenwich Railway Station."--"The
Committee of the House of Commons, to whom the Greenwich and Woolwich
Line of the South Eastern Railway was referred, finally assented to
the adoption of a line which I indicated, passing between the
buildings of the Hospital Schools and the public road to
Woolwich."--"The Galvanic Chronometer attached to the S. E. Equatoreal
often gave us a great deal of trouble. At last I determined, on the
proposal of Mr Ellis, to attempt an extension of Mr R. L. Jones's
regulating principle. It is well known that Mr Jones has with great
success introduced the system of applying galvanic currents
originating in the vibrations of a normal pendulum, not to drive the
wheelwork of other clocks, but to regulate to exact agreement the
rates of their pendulums which were, independently, nearly in
agreement; each clock being driven by weight-power as before. The same
principle is now applied to the chronometer.... The construction is
perfectly successful; the chronometer remains in coincidence with the
Transit Clock through any length of time, with a small constant error
as is required by mechanical theory."--"The printed volume of
Observations for 1864 has two Appendixes; one containing the
calculations of the value of the Moon's Semi-diameter deduced from 295
Occultations observed at Cambridge and Greenwich from 1832 to 1860,
and shewing that the Occultation Semi-diameter is less than the
Telescopic Semi-diameter by 2"; the other containing the reduction of
the Planetary Observations made at the Royal Observatory in the years
1831-1835; filling up the gap, between the Planetary Reductions
1750-1830 made several years ago under my superintendence, and the
Reductions contained in the Greenwich Volumes 1836 to the present
time: and conducted on the same general principles."--"Some trouble
had been found in regulating the temperature of the Magnetic Basement,
but it was anticipated that in future there would be no difficulty in
keeping down the annual variation within about 5° and the diurnal
variation within 3°.--Longitudes in America were determined in this
year by way of Valencia and Newfoundland: finished by Nov. 14th."
Of private history: In April he made a short visit to Ventnor in the
Isle of Wight.--From June 15th to July 23rd he was on an expedition in
Norway with his son Osmund and his nephew Gorell Barnes.--There was
probably a short stay at Playford in the winter.
In this and in the previous year (1865) the free-thinking
investigations of Colenso, the Bishop of Natal, had attracted much
notice, and had procured him the virulent hostility of a numerous
section. His income was withheld from him, and in consequence a
subscription fund was raised for his support by his admirers. Airy,
who always took the liberal side in such questions, was a subscriber
to the fund, and wrote the following letter to the Bishop:
ROYAL OBSERVATORY, GREENWICH, S.E.,
_1865, July 24_.
MY LORD,
With many thanks I have to acknowledge your kind recollection of me in
sending as a presentation copy the work on Joshua, Judges, and
especially on the divided authorship of Genesis; a work whose
investigations, founded in great measure on severe and extensive
verbal criticism, will apparently bear comparison with your Lordship's
most remarkable examination of Deuteronomy. I should however not do
justice to my own appreciation if I did not remark that there are
other points considered which have long been matters of interest to
me.
On several matters, some of them important, my present conclusions do
not absolutely agree with your Lordship's. But I am not the less
grateful for the amount of erudition and thought carefully directed to
definite points, and above all for the noble example of unwearied
research and freedom in stating its consequences, in reference to
subjects which scarcely ever occupy the attention of the clergy in our
country.
I am, My Lord,
Yours very faithfully,
G.B. AIRY.
_The Lord Bishop of Natal_.
* * * * *
Here also is a letter on the same subject, written to Professor
Selwyn, Professor of Divinity at Cambridge:--
ROYAL OBSERVATORY, GREENWICH,
LONDON, S.E.,
_1866, May 5_.
MY DEAR SIR,
The MS. concerning Colenso duly arrived.
I note your remarks on the merits of Colenso. I do not write to tell
you that I differ from you, but to tell you why I differ.
I think that you do not make the proper distinction between a person
who invents or introduces a tool, and the person who uses it.
The most resolute antigravitationist that ever lived might yet
acknowledge his debt to Newton for the Method of Prime and Ultimate
Ratios and the Principles of Fluxions by which Newton sought to
establish gravitation.
So let it be with Colenso. He has given me a power of tracing out
truth to a certain extent which I never could have obtained without
him. And for this I am very grateful.
As to the further employment of this power, you know that he and I use
it to totally different purposes. But not the less do I say that I owe
to him a new intellectual power.
I quite agree with you, that the sudden disruption of the old
traditional view seems to have unhinged his mind, and to have sent him
too far on the other side. I would not give a pin for his judgment.
Nevertheless, I wish he would go over the three remaining books of the
Tetrateuch.
I know something of Myers, but I should not have thought him likely to
produce anything sound on such things as the Hebrew Scriptures. I
never saw his "Thoughts."
I am, my dear Sir,
Yours very truly,
G.B. AIRY.
_Professor Selwyn_.
* * * * *
The following letter has reference to Airy's proposal to introduce
certain Physico-Mathematical subjects into the Senate-House
Examination for B.A. Honors at Cambridge. On various occasions he
sharply criticized the Papers set for the Senate-House Examination and
the Smith's Prize Examination, and greatly lamented the growing
importance of pure mathematics and the comparative exclusion of
physical questions in those examinations. His proposal as finally
submitted in the letter that follows was somewhat modified (as regards
the mode of introducing the subjects) from his original draft, in
deference to the opinions of Whewell, Adams, Routh, and other friends
to whom he had submitted it. His proposal was favourably received by
the Mathematical Board, and recommendations were made in the
direction, though not to the extent, that he desired, and he
subsequently submitted a Memorandum on those recommendations:
ROYAL OBSERVATORY, GREENWICH,
_1866, May 11_.
MY DEAR SIR,
You will perceive, from perusal of the enclosed paper, that I have
acted on the permission which you kindly gave me, to transmit to you
my proposal for extension of the mathematical education of the
University in the Physical direction.
It is an unavoidable consequence of the structure of the University
that studies there will have a tendency to take an unpractical form
depending much on the personal tastes of special examiners. I trust
that, as a person whose long separation from the daily business of the
University has enabled him to see in some measure the wants of the
external scientific and practical world, I may be forgiven this
attempt to bring to the notice of the University my ideas on the
points towards which their attention might perhaps be advantageously
turned.
I am, my dear Sir,
Very faithfully yours,
G.B. AIRY.
_The Rev. Dr Cartmell,
Master of Christ's College
and Vice-Chancellor._
ROYAL OBSERVATORY, GREENWICH,
_1866, May 11_.
MY DEAR MR VICE-CHANCELLOR,
About two years ago, by the kindness of the University, an opportunity
was presented to me of orally stating what I conceived to be
deficiencies in the educational course of the University as regards
mathematical physics. Since that time, the consideration of those
deficiencies, which had long been present to me, has urged itself on
my attention with greater force: and finally I have entertained the
idea that I might without impropriety communicate to you my opinion,
in a less fugitive form than on the occasion to which I have alluded:
with the request that, if you should deem such a course appropriate,
you would bring it before the Board of Mathematical Studies, and
perhaps ultimately make it known to the Resident Members of the
Senate.
I will first give the list of subjects, which I should wish to see
introduced, and to the prosecution of which the generally admirable
course of the University is remarkably well adapted: and I will then,
without entering into every detail, advert to the process by which I
think it probable the introduction of these subjects could be
effected.
In the following list, the first head is purely algebraical, and the
second nearly so: but they are closely related to observational
science, and to the physical subjects which follow. Some of the
subjects which I exhibit on my list are partially, but in my opinion
imperfectly, taught at present. I entirely omit from my list Physical
Optics, Geometrical Astronomy, and Gravitational Astronomy of Points:
because, to the extent to which Academical Education ought to go, I
believe that there is no teaching on these sciences comparable to that
in the University of Cambridge. (It is, of course, still possible that
improvements may be made in the books commonly used.) It might,
however, be a question, whether, as regards the time and manner of
teaching them, some parts of these subjects might ultimately be
associated with the other subjects included in my list.
I. _List of subjects proposed for consideration_.
(1) Partial Differential Equations to the second order, with their
arbitrary functions: selected principally with reference to the
physical subjects.
(2) The Theory of Probabilities as applied to the combination of
Observations.
(3) Mechanics (including Hydraulic Powers) in the state which verges
upon practical application, and especially including that part in
which the abstract ideas of _power_ and _duty_ occur.
(4) Attractions. This subject is recognized in the existing course of
the University: but, so far as I can infer from examination-papers, it
appears to be very lightly passed over.
(5) The Figure of the Earth, and its consequences, Precession, &c. I
believe that the proposal is sanctioned, of adopting some part of this
theory in the ordinary course; but perhaps hardly so far as is
desirable.
(6) The Tides.
(7) Waves of Water.
(8) Sound (beginning with Newton's investigation); Echoes; Pipes and
Vibrating Strings; Acoustics; the Mathematical part of Music.
(9) Magnetism, terrestrial and experimental, and their connection.
(I omit for the present Mineralogy and Mathematical Electricity.)
This list of subjects appears formidable: but they are in reality
easy, and would be mastered in a short time by the higher Wranglers.
II. _Mode of introducing these subjects into the University_.
After much consideration, and after learning the opinions of several
persons whose judgment claims my deepest respect, I propose the
gradual introduction of these subjects into the Examination for Honors
at admission to the B.A. Degree, as soon as the preparation of Books
and the readiness of Examiners shall enable the University to take
that step. I conceive that, by a judicious pruning of the somewhat
luxuriant growth of Pure Algebra, Analytical Geometry, and Mere
Problems, sufficient leisure may be gained for the studies of the
undergraduates, and sufficient time for the questions of the
examiners. I do not contemplate that the students could advance very
far into the subjects; but I know the importance of beginning them;
and, judging from the train of thoughts, of reading, and of
conversation, among the Bachelors with whom I associated many years
ago, I believe that there is quite a sufficient number who will be
anxious to go deep into the subjects if they have once entered into
them. If six Wranglers annually would take them up, my point would be
gained. The part which these gentlemen might be expected, in a short
time, to take in the government of the University, would enable them
soon to act steadily upon the University course: the efficiency of the
University instruction would be increased; and the external character
of the University would be raised.
The real difficulties, and they are not light ones, would probably be
found in providing Examiners and Books. At present, both are wanting
within the University. Where there is a great and well-founded
objection to intrusting examinations to persons foreign to the
University, and where the books have to be created with labour and
with absolute outlay of money (for their sale could never be
remunerative), the progress must be slow. Still progress would be
certain, if the authorities of the University should think the matter
deserving of their hearty encouragement.
Requesting that you and the Members of the University will accept this
proposal as an indication of my deep attachment to my University,
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.
As the Statute is new, I should be obliged by a copy of it. And, at
any convenient time, I should be glad to know the name of the person
with whom I am so honorably associated.
I am, My dear Master,
Very faithfully yours,
G.B. AIRY.
* * * * *
Consequent on Airy's proposals in 1866 for the introduction of new
physical subjects into the Senate-House Examination and his desire
that the large number of questions set in Pure Mathematics, or as he
termed it "Useless Algebra," should be curtailed, there was a smart
and interesting correspondence between him and Prof. Cayley, who was
the great exponent and advocate of Pure Mathematics at Cambridge. Both
of them were men of the highest mathematical powers, but diametrically
opposed in their views of the use of Mathematics. Airy regarded
mathematics as simply a useful machine for the solution of practical
problems and arriving at practical results. He had a great respect for
Pure Mathematics and all the processes of algebra, so far as they
aided him to solve his problems and to arrive at useful results; but
he had a positive aversion to mathematical investigations, however
skilful and elaborate, for which no immediate practical value could be
claimed. Cayley on the contrary regarded mathematics as a useful
exercise for the mind, apart from any immediate practical object, and
he considered that the general command of mathematics gained by
handling abstruse mathematical investigations (though barren in
themselves) would be valuable for whatever purpose mathematics might
be required: he also thought it likely that his researches and
advances in the field of Pure Mathematics might facilitate the
solution of physical problems and tend to the progress of the
practical sciences. Their different views on this subject will be
seen from the letters that follow:
ROYAL OBSERVATORY, GREENWICH,
LONDON, S.E.
_1867, Nov. 8_.
MY DEAR SIR,
I think it best to put in writing the purport of what I have said, or
have intended to say, in reference to the Mathematical Studies in the
University.
First, I will remark on the study of Partial Differential Equations.
I do not know that one branch of Pure Mathematics can be considered
higher than another, except in the utility of the power which it
gives. Measured thus, the Partial Differential Equations are very
useful and therefore stand very high, as far as the Second Order.
They apply, to that point, in the most important way, to the great
problems of nature concerning _time_, and _infinite division of
matter_, and _space_: and are worthy of the most careful study. Beyond
that Order they apply to nothing. It was for the purpose of limiting
the study to the Second Order, and at the same time working it
carefully, philosophically, and practically, up to that point, that I
drew up my little work.
On the general question of Mathematical Studies, I will first give my
leading ideas on what I may call the moral part. I think that a heavy
responsibility rests on the persons who influence most strongly the
course of education in the University, to direct that course in the
way in which it will be most useful to the students--in the two ways,
of disciplining their powers and habits, and of giving them scientific
knowledge of the highest and most accurate order (applying to the
phenomena of nature) such as will be useful to them through life. I do
not think that the mere personal taste of a teacher is sufficient
justification for a special course, unless it has been adopted under a
consideration of that responsibility. Now I can say for myself that I
have, for some years, inspected the examination papers, and have
considered the bearing of the course which they imply upon the
education of the student, and am firmly convinced that as regards men
below the very few first--say below the ten first--there is a
prodigious loss of time without any permanent good whatever. For the
great majority of men, such subjects as abstract Analytical Geometry
perish at once. With men like Adams and Stokes they remain, and are
advantageous; but probably there is not a single man (beside them) of
their respective years who remembers a bit, or who if he remembers
them has the leisure and other opportunities of applying them.
I believe on the other hand that a careful selection of physical
subjects would enable the University to communicate to its students a
vast amount of information; of accurate kind and requiring the most
logical treatment; but so bearing upon the natural phenomena which are
constantly before us that it would be felt by every student to possess
a real value, that (from that circumstance) it would dwell in his
mind, and that it would enable him to correct a great amount of flimsy
education in the country, and, so far, to raise the national
character.
The consideration of the education of the reasoning habits suggests
ideas far from favourable to the existing course. I am old enough to
remember the time of mere geometrical processes, and I do not hesitate
to say that for the cultivation of accurate mental discipline they
were far superior to the operations in vogue at the present day. There
is no subject in the world more favourable to logical habit than the
Differential Calculus in all its branches _if logically worked in its
elements_: and I think that its applications to various physical
subjects, compelling from time to time an attention to the elementary
grounds of the Calculus, would be far more advantageous to that
logical habit than the simple applications to Pure Equations and Pure
Algebraical Geometry now occupying so much attention.
I am, my dear Sir,
Yours very truly,
G.B. AIRY.
_Professor Cayley_.
* * * * *
DEAR SIR,
I have been intending to answer your letter of the 8th November. So
far as it is (if at all) personal to myself, I would remark that the
statutory duty of the Sadlerian Professor is that he shall explain and
teach the principles of Pure Mathematics and apply himself to the
advancement of the Science.
As to Partial Differential Equations, they are "high" as being an
inverse problem, and perhaps the most difficult inverse problem that
has been dealt with. In regard to the limitation of them to the second
order, whatever other reasons exist for it, there is also the reason
that the theory to this order is as yet so incomplete that there is no
inducement to go beyond it; there could hardly be a more valuable step
than anything which would give a notion of the form of the general
integral of a Partial Differential Equation of the second order.
I cannot but differ from you _in toto_ as to the educational value of
Analytical Geometry, or I would rather say of Modern Geometry
generally. It appears to me that in the Physical Sciences depending on
Partial Differential Equations, there is scarcely anything that a
student can do for himself:--he finds the integral of the ordinary
equation for Sound--if he wishes to go a step further and integrate
the non-linear equation (dy/dx)²(d²y/dt²) = a²(d²y/dx²) he is simply
unable to do so; and so in other cases there is nothing that he can
add to what he finds in his books. Whereas Geometry (of course to an
intelligent student) is a real inductive and deductive science of
inexhaustible extent, in which he can experiment for himself--the very
tracing of a curve from its equation (and still more the consideration
of the cases belonging to different values of the parameters) is the
construction of a theory to bind together the facts--and the selection
of a curve or surface proper for the verification of any general
theorem is the selection of an experiment in proof or disproof of a
theory.
I do not quite understand your reference to Stokes and Adams, as types
of the men who alone retain their abstract Analytical Geometry. If a
man when he takes his degree drops mathematics, he drops geometry--but
if not I think for the above reasons that he is more likely to go on
with it than with almost any other subject--and any mathematical
journal will shew that a very great amount of attention is in fact
given to geometry. And the subject is in a very high degree a
progressive one; quite as much as to Physics, one may apply to it the
lines, Yet I doubt not thro' the ages one increasing purpose runs, and
the thoughts of men are widened with the progress of the suns.
I remain, dear Sir,
Yours very sincerely,
A. CAYLEY.
CAMBRIDGE,
_6 Dec., 1867_.
* * * * *
ROYAL OBSERVATORY, GREENWICH,
LONDON, S.E.
_1867, December 9_.
MY DEAR SIR,
I have received with much pleasure your letter of December 6. In this
University discussion, I have acted only in public, and have not made
private communication to any person whatever till required to do so by
private letter addressed to me. Your few words in Queens' Hall seemed
to expect a little reply.
Now as to the Modern Geometry. With your praises of this science--as
to the room for extension in induction and deduction, &c.; and with
your facts--as to the amount of space which it occupies in
Mathematical Journals; I entirely agree. And if men, after leaving
Cambridge, were designed to shut themselves up in a cavern, they could
have nothing better for their subjective amusement. They might have
other things as good; enormous complication and probably beautiful
investigation might be found in varying the game of billiards with
novel islands on a newly shaped billiard table. But the persons who
devote themselves to these subjects do thereby separate themselves
from the world. They make no step towards natural science or
utilitarian science, the two subjects which the world specially
desires. The world could go on as well without these separatists.
Now if these persons lived only for themselves, no other person would
have any title to question or remark on their devotion to this barren
subject. But a Cambridge Examiner is not in that position. The
University is a national body, for education of young men: and the
power of a Cambridge Examiner is omnipotent in directing the education
of the young men; and his responsibility to the cause of education is
very distinct and very strong. And the question for him to consider
is--in the sense in which mathematical education is desired by the
best authorities in the nation, is the course taken by this national
institution satisfactory to the nation?
I express my belief that it is _not_ satisfactory. I believe that many
of the best men of the nation consider that a great deal of time is
lost on subjects which they esteem as puerile, and that much of that
time might be employed on noble and useful science.
You may remember that the Commissions which have visited Cambridge
originated in a Memorial addressed to the Government by men of
respected scientific character: Sabine was one, and I may take him as
the representative. He is a man of extensive knowledge of the
application of mathematics as it has been employed for many years in
the science of the world; but he has no profundity of science. He, as
I believe, desired to find persons who could enter accurately into
mathematical science, and naturally looked to the Great Mathematical
University; but he must have been much disappointed. So much time is
swallowed up by the forced study of the Pure Mathematics that it is
not easy to find anybody who can really enter on these subjects in
which men of science want assistance. And so Sabine thought that the
Government ought to interfere, probably without any clear idea of what
they could do.
I am, my dear Sir,
Yours very truly,
G.B. AIRY.
_Professor Cayley_.
* * * * *
DEAR SIR,
I have to thank you for your last letter. I do not think everything
should be subordinated to the educational element: my idea of a
University is that of a place for the cultivation of all
science. Therefore among other sciences Pure Mathematics; including
whatever is interesting as part of this science. I am bound therefore
to admit that your proposed extension of the problem of billiards, _if
it_ were found susceptible of interesting mathematical developments,
would be a fit subject of study. But in this case I do not think the
problem could fairly be objected to as puerile--a more legitimate
objection would I conceive be its extreme speciality. But this is not
an objection that can be brought against Modern Geometry as a whole:
in regard to any particular parts of it which may appear open to such
an objection, the question is whether they are or are not, for their
own sakes, or their bearing upon other parts of the science to which
they belong, worthy of being entered upon and pursued.
But admitting (as I do not) that Pure Mathematics are only to be
studied with a view to Natural and Physical Science, the question
still arises how are they best to be studied in that view. I assume
and admit that as to a large part of Modern Geometry and of the Theory
of Numbers, there is no present probability that these will find any
physical applications. But among the remaining parts of Pure
Mathematics we have the theory of Elliptic Functions and of the
Jacobian and Abelian Functions, and the theory of Differential
Equations, including of course Partial Differential Equations. Now
taking for instance the problem of three bodies--unless this is to be
gone on with by the mere improvement in detail of the present
approximate methods--it is at least conceivable that the future
treatment of it will be in the direction of the problem of two fixed
centres, by means of elliptic functions, &c.; and that the discovery
will be made not by searching for it directly with the mathematical
resources now at our command, but by "prospecting" for it in the field
of these functions. Even improvements in the existing methods are more
likely to arise from a study of differential equations in general than
from a special one of the equations of the particular problem: the
materials for such improvements which exist in the writings of
Hamilton, Jacobi, Bertrand, and Bour, have certainly so arisen. And
the like remarks would apply to the physical problems which depend on
Partial Differential Equations.
I think that the course of mathematical study at the University is
likely to be a better one if regulated with a view to the cultivation
of Science, as if for its own sake, rather than directly upon
considerations of what is educationally best (I mean that the best
educational course will be so obtained), and that we have thus a
justification for a thorough study of Pure Mathematics. In my own
limited experience of examinations, the fault which I find with the
men is a want of analytical power, and that whatever else may have
been in defect Pure Mathematics has certainly not been in excess.
I remain, dear Sir,
Yours sincerely,
A. CAYLEY.
CAMBRIDGE,
_10th Dec., 1867_.
* * * * *
_1867, December 17_.
MY DEAR SIR,
Since receiving your letter of 9th I positively have not had time to
express the single remark which I proposed to make on it.
You state your idea that the educational element ought not to be the
predominating element in the University. "I do not think that every
thing should be subordinated to the educational element." I cannot
conceal my surprise at this sentiment. Assuredly the founders of the
Colleges intended them for education (so far as they apply to persons
in statu pupillari), the statutes of the University and the Colleges
are framed for education, and fathers send their sons to the
University for education. If I had not had your words before me, I
should have said that it is impossible to doubt this.
It is much to be desired that Professors and others who exercise no
control by force should take every method, not only of promoting
science in themselves, but also of placing the promoted science before
students: and it is much to be desired that students who have passed
the compulsory curriculum should be encouraged to proceed into the
novelties which will be most agreeable to them. But this is a totally
different thing from using the Compulsory Force of Examination to
drive students in paths traced only by the taste of the examiner. For
them, I conceive the obligation to the nation and the duty to follow
the national sense on education (as far as it can be gathered from its
best representatives) to be undoubted; and to be, in the intensity of
the obligation and duty, most serious.
I am, my dear Sir,
Yours very truly,
G.B. AIRY.
_Professor Cayley_.
* * * * *
1868
"In the South-East Dome, the alteration proposed last year for
rendering the building fire-proof had been completely carried out. The
middle room, which was to be appropriated to Chronometers, was being
fitted up accordingly.--From the Report it appears that 'our
subterranean telegraph wires were all broken by one blow, from an
accident in the Metropolitan Drainage Works on Groom's Hill, but were
speedily repaired.'--In my office as Chairman of successive
Commissions on Standards, I had collected a number of Standards, some
of great historical value (as Ramsden's and Roy's Standards of Length,
Kater's Scale-beam for weighing great weights, and others), &c. These
have been transferred to the newly-created Standards Department of the
Board of Trade."--In the Report is given a detailed account of the
system of preserving and arranging the manuscripts and correspondence
of the Observatory, which was always regarded by Airy as a matter of
the first importance.--From a careful discussion of the results of
observation Mr Stone had concluded that the refractions ought to be
diminished. 'Relying on this, we have now computed our mean
refractions by diminishing those of Bessel's Fundamenta in the
proportion of 1 to 0.99797.'--The Magnetometer-Indications for the
period 1858-1863 had been reduced and discussed, with remarkable
results. It is inferred that magnetic disturbances, both solar and
lunar, are produced mediately by the Earth, and that the Earth in
periods of several years undergoes changes which fit it and unfit it
for exercising a powerful mediate action.--The Earth-current records
had been reduced, and the magnetic effect which the currents would
produce had been computed. The result was, that the agreement between
the magnetic effects so computed and the magnetic disturbances really
recorded by the magnetometers was such as to leave no doubt on the
general validity of the explanation of the great storm-disturbances of
the magnets as consequences of the galvanic currents through the
earth.--Referring to the difficulty experienced in making the
meteorological observations practically available the Report states
thus: 'The want of Meteorology, at the present time, is principally in
suggestive theory.'--In this year Airy communicated to the Royal
Astronomical Society a Paper 'On the Preparatory Arrangements for the
Observation of the Transits of Venus 1874 and 1882': this subject was
now well in hand.--The First Report of the Commissioners (of whom he
was Chairman) appointed to enquire into the condition of the Exchequer
Standards was printed: this business took up much time.--He was in
this year much engaged on the Coinage Commission.
Of private history: There was the usual winter visit to Playford, and
a short visit to Cambridge in June.--From about Aug. 1st to Sept. 3rd
he was travelling in Switzerland with his youngest son and his two
youngest daughters. In the course of this journey they visited
Zermatt. There had been much rain, the rivers were greatly flooded,
and much mischief was done to the roads. During the journey from Visp
to Zermatt, near St Nicholas, in a steep part of the gorge, a large
stone rolled from the cliffs and knocked their baggage horse over the
lower precipice, a fall of several hundred feet. The packages were all
burst, and many things were lost, but a good deal was recovered by men
suspended by ropes.
In this year also Airy was busy with the subject of University
Examination, which in previous years had occupied so much of his
attention, as will be seen from the following letters:
ROYAL OBSERVATORY, GREENWICH,
LONDON, S.E.
_1868, March 12_.
MY DEAR MASTER,
I have had the pleasure of corresponding with you on matters of
University Examination so frequently that I at once turn to you as the
proper person to whom I may address any remarks on that important
subject.
Circumstances have enabled me lately to obtain private information of
a most accurate kind on the late Mathematical Tripos: and among other
things, I have received a statement of every individual question
answered or partly answered by five honour-men. I have collected the
numbers of these in a small table which I enclose.
I am struck with the _almost_ nugatory character of the five days'
honour examination as applied to Senior Optimes, and I do not doubt
that it is _totally_ nugatory as applied to Junior Optimes. It appears
to me that, for all that depends on these days, the rank of the
Optimes is mere matter of chance.
In the examinations of the Civil Service, the whole number of marks is
published, and also the number of marks gained by each candidate. I
have none of their papers at hand, but my impression is that the
lowest candidates make about 1 in 3; and the fair candidates about 2
in 3, instead of 1 in 10 or 1 in 13 as our good Senior Optimes.
I am, my dear Master,
Very truly yours,
G.B. AIRY.
_The Rev. Dr Cookson,
Master of St Peters College,
&c. &c._
The Table referred to in the above letter is as follows:
Number of Questions, and numbers of Answers to Questions as given by
several Wranglers and Senior Optimes, in the Examination of
Mathematical Tripos for Honours, 1868, January 13, 14, 15, 16, 17.
Number of Questions and Riders in the Printed Papers.
Questions. Riders. Aggregate.
In the 10 Papers of the 5 days 123 101 224
NUMBER OF QUESTIONS AND RIDERS ANSWERED.
Questions. Riders. Aggregate.
By a Wrangler, between the
1st and 7th 69-1/2 25-1/2 95 1 in 2.36
By a Wrangler, between the
12th and 22nd 48-1/2 12-1/2 61 1 in 3.68
By a Wrangler, between the
22nd and 32nd 36 12-1/2 48-1/2 1 in 4.62
By a Sen. Opt. between the
1st and 10th 17-1/2 5 22-1/2 1 in 9.95
By a Sen. Opt. between the
10th and 20th 14-1/2 2 16-1/2 1 in 3.60
G.B. AIRY.
_1868, March 12_.
* * * * *
ST PETER'S COLLEGE LODGE, CAMBRIDGE,
_March 13th, 1868_.
MY DEAR SIR,
I am much obliged by your letter and enclosed paper.
Anything done in the last five days by a Junior Optime only shews
(generally) that he has been employing some of his time
_mischievously_, for he must have been working at subjects which he is
quite unable to master or cramming them by heart on the chance of
meeting with a stray question which he may answer.
The chief part of the Senior Optimes are in something of the same
situation.
I think that the proposed addition of a day to the first part of the
Examination, in which "easy questions in physical subjects" may be
set, is, on this account, a great improvement.
Our new Scheme comes on for discussion on Friday next, March 20, at 2
p.m. in the Arts School. It is much opposed by private tutors,
examiners and others, and may possibly be thrown out in the Senate
this year, though I hope that with a little patience it may be
carried, in an unmutilated form, eventually.
The enclosed Report on the Smith's Prize Examination will be discussed
at the same time.
I will consider what is best to be done on the subject to which your
note refers, without delay. With many thanks,
I am,
Very faithfully yours,
H.W. COOKSON,
_The Astronomer Royal._
* * * * *
In this year certain Members of the Senate of the University of
Cambridge petitioned Parliament against the abolition of religious
declarations required of persons admitted to Fellowships or proceeding
to the degree of M.A. The document was sent to Airy for his signature,
and his reply was as follows:
ROYAL OBSERVATORY, GREENWICH,
LONDON, S.E.
_1868, March 18_.
MY DEAR SIR,
Though I sympathize to a great extent with the prayer of the petition
to Parliament which you sent to me yesterday, and assent to most of
the reasons, I do not attach my signature to it, for the following
considerations:
1. I understand, from the introductory clause, and from the
unqualified character of the phrase "any such measures" in the second
clause, that the petition objects to granting the M.A. degree without
religious declaration. I do not see any adequate necessity for this
objection, and I cannot join in it.
2. It appears to me that the Colleges were intended for two collateral
objects:--instruction by part of the Fellows, on a religious basis;
and support of certain Fellows for scientific purposes, without the
same ostentatious connection with religion. I like this spirit well,
and should be glad to maintain it.
3. I therefore think (as I have publicly stated before) that the
Master of the College ought to be in holy orders; and so ought those
of the Fellows who may be expected to be usually resident and to take
continuous part in the instruction. But there are many who, upon
taking a fellowship, at once lay aside all thoughts of this: and I
think that such persons ought not to be trammelled with declarations.
4. My modification of existing regulations, if it once got into shape,
would I dare say be but a small fraction of that proposed by the
"measures in contemplation." Still I do not like to join in
unqualified resistance to interference in the affairs of the
Established Colleges, with that generality of opposition to
interference which the petition seems to intimate.
I agree with articles 3, 4, and 5; and I am pleased with the graceful
allusion in article 4 to the assistance which has been rendered by the
Colleges, and by none perhaps so honourably as Trinity, to the
parishes connected with it. And I could much wish that the spirit of 3
and 5 could be carried out, with some concession to my ideas in _my_
paragraph 3, above.
I am, my dear Sir,
Yours very truly,
G.B. AIRY.
_Rev. Dr Lightfoot._
* * * * *
1869
From the Report to the Board of Visitors it appears that application
had been made for an extension of the grounds of the Observatory to a
distance of 100 feet south of the Magnetic Ground, and that a Warrant
for the annexation of this space was signed on 1868, Dec. 8. The new
Depôt for the Printed Productions of the Observatory had been
transferred to its position in the new ground, and the foundations for
the Great Shed were completed.--"The courses of our wires for the
registration of spontaneous terrestrial galvanic currents have been
entirely changed. The lines to Croydon and Deptford are abandoned; and
for these are substituted, a line from Angerstein Wharf to Lady Well
Station, and a line from North Kent Junction to Morden College
Tunnel. At each of these points the communication with Earth is made
by a copper plate 2 feet square. The straight line connecting the
extreme points of the first station intersects that connecting the two
points of the second station, nearly at right angles, and at little
distance from the Observatory.--The question of dependence of the
measurable amount of sidereal aberration upon the thickness of glass
or other transparent material in the telescope (a question which
involves, theoretically, one of the most delicate points in the
Undulatory Theory of Light) has lately been agitated on the Continent
with much earnestness. I have calculated the curvatures of the lenses
of crown and flint glass (the flint being exterior) for correcting
spherical and chromatic aberration in a telescope whose tube is filled
with water, and have instructed Mr Simms to proceed with the
preparation of an instrument carrying such a telescope. I have not
finally decided whether to rely on Zenith-distances of gamma Draconis
or on right-ascensions of Polaris. In any form the experiment will
probably be troublesome.--The transit of Mercury on 1868, Nov. 4th,
was observed by six observers. The atmospheric conditions were
favourable; and the singular appearances usually presented in a
planetary transit were well seen.--Mr Stone has attached to the
South-East Equatoreal a thermo-multiplier, with the view of examining
whether heat radiating from the principal stars can be made sensible
in our instruments. The results hitherto obtained are encouraging, but
they shew clearly that it is vain to attempt this enquiry except in
the most superb weather; and there has not been a night deserving that
epithet for some months past.--The preparations for observing the
Transits of Venus were now begun in earnest. I had come to the
conclusion, that after every reliance was placed on foreign and
colonial observatories, it would be necessary for the British
Government to undertake the equipment of five or six temporary
stations. On Feb. 15th I sent a pamphlet on the subject to Mr Childers
(First Lord of Admiralty), and in April I wrote to the Secretary,
asking authority for the purchase of instruments. On June 22nd
authority is given to me for the instruments: the Treasury assent to
_£10,500_. On August 9th I had purchased 3 equatoreals.--I have given
a short course of Lectures in the University of Cambridge on the
subject of Magnetism, with the view of introducing that important
physical science into the studies of the University. The want of books
available to Students, and the novelty of the subject, made the
preparation more laborious than the duration of the lectures would
seem to imply."--In this year there was much work on the Standards
Commission, chiefly regarding the suggested abolition of Troy Weight,
and several Papers on the subject were prepared by Airy.--He also
wrote a long and careful description of the Great Equatoreal at
Greenwich.
Of private history: There was the usual visit to Playford in the
winter. Mrs Airy was now becoming feebler, and did not now leave
Greenwich: since April of this year her letters were written in
pencil, and with difficulty, but she still made great efforts to keep
up the accustomed correspondence.--In April Airy went to Cambridge to
deliver his lectures on magnetism to the undergraduates: the following
passage occurs in one of his letters at this time: "I have a mighty
attendance (there were 147 names on my board yesterday), and, though
the room is large with plenty of benches, I have been obliged to bring
in some chairs. The men are exceedingly attentive, and when I look up
I am quite struck to see the number of faces staring into mine. I go
at 12, and find men at the room copying from my big papers: I lecture
from 1 to 2, and stop till after 3, and through the last hour some men
are talking to me and others are copying from the papers; and I
usually leave some men still at work. The men applaud and shew their
respect very gracefully. There are present some two or three persons
who attended my former lectures, and they say that I lecture exactly
as I did formerly. One of my attendants is a man that they say cannot,
from years and infirmity and habit, be induced to go anywhere else: Dr
Archdall, the Master of Emmanuel. I find that some of my old
lecturing habits come again on me. I drink a great deal of cold water,
and am very glad to go to bed early."--From June 10th-30th he was
travelling in Scotland, and staying at Barrow House near Keswick (the
residence of Mr Langton), with his son Hubert.--Subsequently, from
Aug. 17th to 31st, he was again in the Lake District, with his
daughter Christabel, and was joined there by his son Hubert on the
24th. The first part of the time was spent at Tarn Bank, near
Carlisle, the residence of Mr Isaac Fletcher, M.P. From thence he made
several expeditions, especially to Barrow in Furness and Seascale,
where he witnessed with great interest the Bessemer process of making
steel. From Barrow House he made continual excursions among the
Cumberland mountains, which he knew so well.
1870
"In this year Mr Stone, the First Assistant, was appointed to the Cape
of Good Hope Observatory, and resigned his post of First Assistant. Mr
Christie was appointed in his place.--From the Report to the Visitors
it appears that 'A few months since we were annoyed by a failure in
the illumination of the field of view of the Transit Circle. The
reflector was cleaned, but in vain; at last it was discovered that one
of the lenses (the convex lens) of the combination which forms the
object-glass of a Reversed Telescope in the interior of the
Transit-axis, and through which all illuminating light must pass, had
become so corroded as to be almost opaque.'--The South-East Equatoreal
has been partly occupied with the thermo-multiplier employed by Mr
Stone for the measure of heat radiating from the principal stars. Mr
Stone's results for the radiation from Arcturus and alpha Lyrae appear
to be incontrovertible, and to give bases for distinct numerical
estimation of the radiant heat of these stars.--In my last Report I
alluded to a proposed systematic reduction of the meteorological
observations during the whole time of their efficient
self-registration. Having received from the Admiralty the funds
necessary for immediate operations, I have commenced with the
photographic registers of the thermometers, dry-bulb and wet-bulb,
from 1848 to 1868.--Our chronometer-room contains at present 219
chronometers, including 37 chronometers which have been placed here by
chronometer-makers as competing for the honorary reputation and the
pecuniary advantages to be derived from success in the half-year's
trial to which they are subjected. I take this opportunity of stating
that I have uniformly advocated the policy of offering good prices for
the chronometers of great excellence, and that I have given much
attention to the decision on their merits; and I am convinced that
this system has greatly contributed to the remarkably steady
improvement in the performance of chronometers. In the trial which
terminated in August 1869, the best chronometers (taking as usual the
average of the first six) were superior in merit to those of any
preceding year.--With the funds placed at my disposal for the Transit
of Venus 1874 I purchased three 6-inch equatoreals, and have ordered
two: I have also ordered altazimuths (with accurate vertical circles
only), and clocks sufficient, as I expect, to equip five stations. For
methods of observation, I rely generally on the simple
eye-observation, possibly relieved of some of its uncertainty by the
use of my colour-correcting eyepiece. But active discussion has taken
place on the feasibility of using photographic and spectroscopic
methods; and it will not be easy for some time to announce that the
plan of observations is settled.--There can be no doubt, I imagine,
that the first and necessary duty of the Royal Observatory is to
maintain its place well as an Observing Establishment; and that this
must be secured, at whatever sacrifice, if necessary, of other
pursuits. Still the question has not unfrequently presented itself to
me, whether the duties to which I allude have not, by force of
circumstances, become too exclusive; and whether the cause of Science
might not gain if, as in the Imperial Observatory of Paris for
instance, the higher branches of mathematical physics should not take
their place by the side of Observatory routine. I have often felt the
desire practically to refresh my acquaintance with what were once
favourite subjects: Lunar Theory and Physical Optics. But I do not at
present clearly see how I can enter upon them with that degree of
freedom of thought which is necessary for success in abstruse
investigations."
Of private history: There was a longer visit than usual to Playford,
lasting till Jan. 27th.--In April he made a short excursion (of less
than a week) with his son Hubert to Monmouth, &c.--From June 14th to
July 2nd he was staying at Barrow House, near Keswick, with his son
Hubert: during this time he was much troubled with a painful
skin-irritation of his leg and back, which lasted in some degree for a
long time afterwards.--From Sept. 25th to Oct. 6th he made an
excursion with his daughter Christabel to Scarborough, Whitby, &c.,
and again spent a few days at Barrow House.
1871
"In April 1870 the Assistants had applied for an increase of salary, a
request which I had urged strongly upon the Admiralty. On Jan. 27 of
this year the Admiralty answered that, on account of Mr Childers's
illness, the consideration must be deferred to next year! The
Assistants wrote bitterly to me: and with my sanction they wrote to
the First Lord. On Jan. 31st I requested an interview with Mr Baxter
(secretary of the Admiralty), and saw him on Feb. 3rd, when I obtained
his consent to an addition of _£530_. There was still a difficulty
with the Treasury, but on June 27th the liberal scale was
allowed.--Experiments made by Mr Stone shew clearly that a local
elevation, like that of the Royal Observatory on the hill of Greenwich
Park, has no tendency to diminish the effect of railway tremors.--The
correction for level error in the Transit Circle having become
inconveniently large, a sheet of very thin paper, 1/270 inch in
thickness, was placed under the eastern Y, which was raised from its
bed for the purpose. The mean annual value of the level-error appears
to be now sensibly zero.--As the siege and war operations in Paris
seriously interfered with the observations of small planets made at
the Paris Observatory, observations of them were continued at
Greenwich throughout each entire lunation during the investment of the
city.--The new Water-Telescope has been got into working order, and
performs most satisfactorily. Observations of gamma Draconis have been
made with it, when the star passed between 20h and 17h, with some
observations for adjustment at a still more advanced time. As the
astronomical latitude of the place of observation is not known, the
bearing of these observations on the question of aberration cannot be
certainly pronounced until the autumn observations shall have been
made; but supposing the geodetic latitude to be accordant with the
astronomical latitude, the result for aberration appears to be
sensibly the same as with ordinary telescopes.--Several years since, I
prepared a barometer, by which the barometric fluctuations were
enlarged, for the information of the public; its indications are
exhibited on the wall, near to the entrance gate of the Observatory. A
card is now also exhibited, in a glass case near the public barometer,
giving the highest and lowest readings of the thermometer in the
preceding twenty-four hours.--Those who have given attention to the
history of Terrestrial Magnetism are aware that Halley's Magnetic
Chart is very frequently cited; but I could not learn that any person,
at least in modern times, had seen it. At last I discovered a copy in
the library of the British Museum, and have been allowed to take
copies by photolithography. These are appended to the Magnetical and
Meteorological Volume for 1869.--The trials and certificates of
hand-telescopes for the use of the Royal Navy have lately been so
frequent that they almost become a regular part of the work of the
Observatory. I may state here that by availing myself of a theory of
eyepieces which I published long since in the Cambridge Transactions,
I have been able to effect a considerable improvement in the
telescopes furnished to the Admiralty.--The occurrence of the Total
Eclipse of the Sun in December last has brought much labour upon the
Observatory. As regards the assistants and computers, the actual
observation on a complicated plan with the Great Equatoreal (a plan
for which few equatoreals are sufficiently steady, but which when
properly carried out gives a most complete solution of the geometrical
problem) has required, in observation and in computation, a large
expenditure of time.--My preparations for the Transit of Venus have
respect only to eye-observation of contact of limbs. With all the
liabilities and defects to which it is subject, this method possesses
the inestimable advantage of placing no reliance on instrumental
scales. I hope that the error of observation may not exceed four
seconds of time, corresponding to about 0.13" of arc. I shall be very
glad to see, in a detailed form, a plan for making the proper measures
by heliometric or photographic apparatus; and should take great
interest in combining these with the eye-observations, if my selected
stations can be made available. But my present impression is one of
doubt on the certainty of equality of parts in the scale employed. An
error depending on this cause could not be diminished by any
repetition of observations."--After referring to the desirability of
vigorously prosecuting the Meteorological Reductions (already begun)
and of discussing the Magnetic Observations, the Report concludes
thus: "There is another consideration which very often presents itself
to my mind; the waste of labour in the repetition of observations at
different observatories..... I think that this consideration ought not
to be put out of sight in planning the courses of different
Observatories."--In this year De Launay's Lunar Theory was
published. This valuable work was of great service to Airy in the
preparation of the Numerical Lunar Theory, which he subsequently
undertook.--In the latter part of this year Airy was elected President
of the Royal Society, and held the office during 1872 and 1873. At
this time he was much pressed with work, and could ill afford to take
up additional duties, as the following quotation from a letter to one
of his friends shews: "The election to the Presidency of R.S. is
flattering, and has brought to me the friendly remembrances of many
persons; but in its material and laborious connections, I could well
have dispensed with it, and should have done so but for the respectful
way in which it was pressed on me."
Of private history: There was the usual winter visit to Playford.--In
April he made a short trip to Cornwall with his daughter Annot.--In
June he was appointed a Companion of the Bath, and was presented at
Court on his appointment.--Mrs Airy was staying with her daughter, Mrs
Routh, at Hunstanton, during June, her state of health being somewhat
improved.--From August 1st to 28th he was chiefly in Cumberland, at
Barrow House, and at Grange, Borrowdale, where his son Osmund was
staying for a holiday.
1872
"From the Report to the Board of Visitors it appears that 'The Normal
Siderial Clock for giving sidereal time by galvanic communication to
the Astronomical Observatory was established in the Magnetic Basement
in 1871, June; that locality being adapted for it on account of the
uniformity of temperature, the daily changed of temperature rarely
exceeding 1° Fahrenheit. Its escapement is one which I suggested many
years ago in the Cambridge Transactions; a detached escapement, very
closely analogous to the ordinary chronometer escapement, the pendulum
receiving an impulse only at alternate vibrations.... The steadiness
of rate is very far superior to any that we have previously
attained.'--The aspect of railway enterprise is at present favourable
to the Park and to the Observatory. The South-Eastern Railway Company
has made an arrangement with the Metropolitan Board of Works for
shifting the course of the great Southern Outfall Sewer. This enables
the Company to trace a new line for the railway, passing on the north
side of London Street, at such a distance from the Observatory as to
remove all cause of alarm. I understand that the Bill, which was
unopposed, has passed the Committee of the House of Commons. I trust
that the contest, which has lasted thirty-seven years, is now
terminated.--The observations of 7 Draconis with the Water-Telescope,
made in the autumn of 1871, and the spring of 1872, are reduced, the
latter only in their first steps.... Using the values of the level
scales as determined by Mr Simms (which I have no reason to believe to
be inaccurate) the spring and autumn observations of 1871 absolutely
negative the idea of any effect being produced on the constant of
aberration by the amount of refracting medium traversed by the
light.--The great Aurora of 1872 Feb. 4 was well observed. On this
occasion the term Borealis would have been a misnomer, for the
phenomenon began in the South and was most conspicuous in the
South. Three times in the evening it exhibited that umbrella-like
appearance which has been called (perhaps inaccurately) a corona. I
have very carefully compared its momentary phenomena with the
corresponding movements of the magnetometers. In some of the most
critical times, the comparison fails on account of the violent
movements and consequent faint traces of the magnetometers. I have not
been able to connect the phases of aurora and those of magnetic
disturbance very distinctly.--The Report contains a detailed account
of the heavy preparations for the observation of the Transit of Venus
1874, including the portable buildings for the instruments, the
instruments themselves (being a transit-instrument, an altazimuth, and
an equatoreal, for each station), and first class and second-class
clocks, all sufficient for the equipment of 5 stations, and continues
thus: I was made aware of the assent of the Government to the wish of
the Board of Visitors, as expressed at their last meeting, that
provision should be made for the application of photography to the
observation of the Transit of Venus. It is unnecessary for me to
remark that our hope of success is founded entirely on our confidence
in Mr De La Rue. Under his direction, Mr Dallmeyer has advanced far in
the preparation of five photoheliographs.... The subject is recognized
by many astronomers as not wholly free from difficulties, but it is
generally believed that these difficulties may be overcome, and Mr De
La Rue is giving careful attention to the most important of them.--I
take this opportunity of reporting to the Board that the Observatory
was honoured by a visit of His Majesty the Emperor of Brazil, who
minutely examined every part."--After referring to various subjects
which in his opinion might be usefully pursued systematically at the
Observatory, the Report proceeds thus: "'The character of the
Observatory would be somewhat changed by this innovation, but not, as
I imagine, in a direction to which any objection can be made. It would
become, pro tanto, a physical observatory; and possibly in time its
operations might be extended still further in a physical
direction.'--The consideration of possible changes in the future of
the Observatory leads me to the recollection of actual changes in the
past. In my Annual Reports to the Visitors I have endeavoured to
chronicle these; but still there will be many circumstances which at
present are known only to myself, but which ought not to be beyond the
reach of history. I have therefore lately employed some time in
drawing up a series of skeleton annals of the Observatory (which
unavoidably partakes in some measure of the form of biography), and
have carried it through the critical period, 1836-1851. If I should
command sufficient leisure to bring it down to 1861, I think that I
might then very well stop." (The skeleton annals here referred to are
undoubtedly the manuscript notes which form the basis of the present
biography. Ed.)--"On Feb. 23rd in this year I first (privately) formed
the notion of preparing a numerical Lunar Theory by substituting
Delaunay's numbers in the proper Equations and seeing what would come
of it."
Of private history: There was the usual visit to Playford--in this
year later than usual--from Feb. 4th to Mar. 4th. The letters written
during this visit are, as usual, full of freshness and delight at
finding himself in his favourite country village.--On June 5th he went
to Barrow House, near Keswick, to be present at the marriage of his
second son Hubert to Miss S. C. Langton, daughter of Z. Langton Esq.,
of Barrow House.--After the wedding he made a trip through the
Trossachs district of Scotland with his daughter Annot, and returned
to Greenwich on June 17th.
On the 26th June 1872 Airy was appointed a Knight Commander of the
Most Honourable Order of the Bath: he was knighted by the Queen at
Osborne on the 30th of July. In the course of his official career he
had three times been offered Knighthood, and had each time declined
it: but it seemed now as if his scruples on the subject were removed,
and it is probable that he felt gratified by the public recognition of
his services. Of course the occasion produced many letters of
congratulation from his friends: to one of these he replied as
follows: "The real charm of these public compliments seems to be, that
they excite the sympathies and elicit the kind expressions of private
friends or of official superiors as well as subordinates. In every way
I have derived pleasure from these." From the Assistants of the Royal
Observatory he received a hearty letter of congratulation containing
the following paragraph. "Our position has naturally given us peculiar
opportunities for perceiving the high and broad purposes which have
characterized your many and great undertakings, and of witnessing the
untiring zeal and self-denial with which they have been pursued."
* * * * *
On the 18th of March 1872 Airy was nominated a Foreign Associate of
the Institut de France, to fill the place vacant by the death of Sir
John Herschel. The following letter of acknowledgment shews how much
he was gratified by this high scientific honour:
ROYAL OBSERVATORY, GREENWICH,
_1872, March 23_.
_À_ Messieurs
Messieurs ELIE DE BEAUMONT,
_et_ J.B. DUMAS,
_Secrétaires perpetuels de l'Académie
des Sciences, Institut de France._
GENTLEMEN,
I am honoured with your letter of March 18, communicating to me my
nomination by the Academy of Sciences to the place rendered vacant in
the class of Foreign Associates of the Academy by the decease of Sir
John Herschel, and enclosing Copy of the Decree of the President of
the French Republic approving the Election.
It is almost unnecessary for me to attempt to express to you the pride
and gratification with which I receive this announcement. By universal
consent, the title of _Associé Etranger de l'Académie des Sciences_ is
recognised as the highest distinction to which any man of science can
aspire; and I can scarcely imagine that, unless by the flattering
interpretation of my friends in the Academy, I am entitled to bear
it. But in any case, I am delighted to feel that the bands of
friendship are drawn closer between myself and the distinguished body
whom, partly by personal intercourse, partly by correspondence, and in
every instance by reputation, I have known so long.
I beg that you will convey to the Academy my long-felt esteem for that
body in its scientific capacity, and my deep recognition of its
friendship to me and of the honor which it has conferred on me in the
late election.
I have the honor to be
Gentlemen,
Your very faithful servant,
G.B. AIRY.
* * * * *
On the 20th November 1872 Airy was nominated a Grand Cross in the
Imperial Order of the Rose of Brazil: the insignia of the Order were
accompanied by an autograph letter from the Emperor of Brazil, of
which the following is a transcript.
MONSIEUR,
Vous êtes un des doyens de la science, et le Président de l'illustre
Société, qui a eu la bienveillance d'inscrire mon nom parmi ceux de
ses associés. La manière, dont vous m'avez fait les honneurs de votre
Observatoire m'a imposé aussi l'agréable devoir d'indiquer votre nom à
l'empereur de Brésil pour un témoignage de haute estime, dont je suis
fort heureux de vous faire part personellement, en vous envoyant les
décorations que vous garderez, an moins, comme un souvenir de ma
visite à Greenwich.
J'espère que vous m'informerez, quand il vous sera aisé, des travaux
de votre observatoire, et surtout de ce que l'on aura fait pour
l'observation du passage de Vénus et la détermination exacte de la
passage.
J'ai reçu déjà les _Proceedings de la Royal Society_ lesquels
m'intéressent vivement.
Je voudrais vous écrire dans votre langue, mais, comme je n'en ai pas
l'habitude, j'ai craigné de ne pas vous exprimer tout-à-fait les
sentiments de
Votre affectionné,
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 year Airy was consulted by Mr
W.H. Barlow, C.E., and Mr Thomas Bouch (the Engineer of the Tay
Bridge, which was blown down in 1879, and of a proposed scheme for a
Forth Bridge in 1873) on the subject of the wind pressure, &c., that
should be allowed for in the construction of the bridge. Airy's report
on this question is dated 1873, Apr. 9th: it was subsequently much
referred to at the Official Enquiry into the causes of the failure of
the Tay Bridge.--At the end of this year Airy resigned the Presidency
of the Royal Society. In his Address to the Society on Dec. 1st he
stated his reasons in full, as follows: "the severity of official
duties, which seem to increase, while vigour to discharge them does
not increase; and the distance of my residence.... Another cause is a
difficulty of hearing, which unfits me for effective action as
Chairman of Council."
Of private history: There was the usual visit to Playford in January:
also a short visit in May: and a third visit at Christmas.--There was
a short run in June, of about a week, to Coniston, with one of his
daughters.--And there was a trip to Weymouth, &c., for about 10 days,
with one of his daughters, in the beginning of August--On his return
from the last-mentioned trip, Airy found a letter from the Secretary
of the Swedish Legation, enclosing the Warrant under the Royal Sign
Manual of His Majesty (Oscar), the King of Sweden and Norway, by which
he was nominated as a First Class Commander of the Order of the North
Star, and accompanying the Decorations of that Order.
1874
"In this year Mr Glaisher resigned his appointment: I placed his
Department (Magnetical and Meteorological) under Mr Ellis.--A balance
of peculiar construction has been made by Mr Oertling, from my
instructions, and fixed near the public barometer at the Entrance
Gate. This instrument enables the public to test any ordinary pound
weight, shewing on a scale the number of grains by which it is too
heavy or too light.--Fresh counterpoises have been attached to the
Great Equatoreal to balance the additional weight of the new
Spectroscope, which was finally received from Mr Browning's hands on
May 2nd of the present year. The Spectroscope is specifically adapted
to sweeping round the Sun's limb, with a view to mapping out the
prominences, and is also available for work on Stars and Nebulae, the
dispersive power being very readily varied. An induction-coil, capable
of giving a six-inch spark, has been made for this instrument by Mr
Browning.--Some new classes of reductions of the meteorological
observations from 1848 to 1868 have been undertaken and completed in
the past year. The general state of this work is as follows: The
diurnal changes of the dry-bulb thermometer, as depending on the
month, on the temperature waves, on the barometric waves, on the
overcast and cloudless states of the sky, and on the direction of the
wind, have been computed and examined for the whole period; and the
exhibition of the results is ready for press. The similar reductions
for the wet-bulb thermometer are rapidly approaching completion.
--Regarding the preparations for the Transit of Venus Expeditions.
Originally five stations were selected and fully equipped
with equatoreals, transits, altazimuths, photoheliographs, and clocks;
but I have since thought it desirable to supplement these by two
branch stations in the Sandwich Islands and one in Kerguelen's Island;
and the additional instruments thus required have been borrowed from
various sources, so that there is now an abundant supply of
instrumental means.... There will thus be available for observation of
the Transit of Venus 23 telescopes, nine of which will be provided
with double-image-micrometers; and five photoheliographs; and for
determination of local time, and latitude and longitude, there will be
nine transits and six altazimuths.... All the observers have undergone
a course of training in photography; first, under a professional
photographer, Mr Reynolds, and subsequently under Capt. Abney, R.E.,
whose new dry-plate process is to be adopted at all the British
Stations.... A Janssen slide, capable of taking 50 photographs of
Venus and the neighbouring part of the Sun's limb at intervals of one
second, has been made by Mr Dallmeyer for each of the five
photoheliographs."--Attached to the Report to the Visitors is a copy
of the Instructions to Observers engaged in the Transit of Venus
Expeditions, prepared with great care and in remarkable detail.--"In
the past spring I published in the Monthly Notices of the Royal
Astronomical Society a statement of the fundamental points in a new
treatment of the Lunar Theory, by which, availing myself of all that
has been done in the best algebraical investigations of that theory, I
trust to be able by numerical operations only to give greater accuracy
to final results. Considerable progress has been made in the extensive
numerical developments, the work being done, at my private expense,
entirely by a junior computer; and I hope, at any rate, to put it in
such a state that there will be no liability to its entire loss. When
this was reported to the Board of Visitors, it was resolved on the
motion of Prof. Stokes, that this work, as a public expense, ought to
be borne by the Government; and this was forwarded to the
Admiralty. On June 24th I wrote to the Secretary of the Admiralty,
asking for _£100_ for the present year, which after the usual
enquiries and explanations was sanctioned on Aug. 29th."
Of private history: There were short visits to Playford in January,
June, and October, but only for a few days in each case.--In March
there was a run of two or three days to Newnham (on the Severn) to see
the Bore on the Severn, and to Malvern.--In July he went to Newcastle
to observe with Mr Newall's great telescope, but the weather was
unfavourable: he then went on to Barrow House near Keswick, and spent
a few days there, with excursions among the mountains.--On Aug. 13th
he went with his daughter Christabel to the Isle of Arran, and then by
Glasgow to the Trosachs, where he made several excursions to verify
the localities mentioned in the "Lady of the Lake."--While in Scotland
he heard of the death of his brother, the Rev. William Airy, and
travelled to Keysoe in Bedfordshire to attend the funeral; and
returned to Greenwich on Aug. 24th.
1875
"In October of this year I wrote to the Admiralty that I had grounds
for asking for an increase of my salary: because the pension which had
been settled on my wife, and which I had practically recognized as
part of my salary, had been terminated by her death; so that my salary
now stood lower by _£200_ than that of the Director of Studies of the
Royal Naval College. The Admiralty reply favourably, and on Nov. 27th
the Treasury raise my salary to _£1_,200.--For the service of the
Clock Movement of the Great Equatoreal, a water-cistern has been
established in the highest part of the Ball-Turret, the necessity for
which arose from the following circumstance: The Water Clock was
supplied by a small pipe, about 80 feet in length, connected with the
3-inch Observatory main (which passes through the Park), at a distance
of about 250 feet from any other branch pipe. In spite of this
distance I have seen that, on stopping the water-tap in the
Battery-Basement under the North-East Turret, the pressure in the
gauge of the Water Clock has been instantly increased by more than 40
lbs. per square inch. The consequent derangement of the Water Clock in
its now incessant daily use became intolerable. Since the independent
supply was provided, its performance has been most satisfactory.--With
the Spectroscope the solar prominences have been mapped on 28 days
only; but the weather of the past winter was exceptionally
unfavourable for this class of observation. After mapping the
prominences, as seen on the C line, the other lines, especially F and
b, have been regularly examined, whenever practicable. Great care has
been taken in determining the position, angle, and heights of the
prominences in all cases. The spectrum of Coggia's Comet was examined
at every available opportunity last July, and compared directly with
that of carbon dioxide, the bands of the two spectra being sensibly
coincident. Fifty-four measures of the displacement of lines in the
spectra of 10 stars, as compared with the corresponding lines in the
spectra of terrestrial elements (chiefly hydrogen), have been made,
but some of these appear to be affected by a constant error depending
on faulty adjustment of the Spectroscope.--Photographs of the Sun have
been taken with the Kew Photoheliograph on 186 days; and of these 377
have been selected for preservation. The Moon, Jupiter, Saturn, and
several stars (including the Pleiades and some double stars) have been
photographed with the Great Equatoreal, with fairly satisfactory
results, though further practice is required in this class of work.--I
would mention a supplemental mechanism which I have myself introduced
into some chronometers. I have long remarked that, in ordinary good
chronometers, the freedom from irregularities depending on mechanical
causes is most remarkable; but that, after all the efforts of the most
judicious makers, there is in nearly every case a perceptible defect
of thermal compensation. There is great difficulty in correcting the
residual fault, not only because an inconceivably small movement of
the weights on the balance-curve is required, but also because it
endangers the equilibrium of the balance. The mechanism adopted to
remedy the defect is described in a Paper in the Horological Journal
of July 1875 by Mr W. Ellis, and has received the approval of some
able chronometer-makers.--With respect to the Transit of Venus
Expeditions: The parties from Egypt and Rodriguez are returned. I am
in continual expectation of the arrival of the other parties. I
believe the eye-observations and the ordinary photographs to be quite
successful; I doubt the advantage of the Janssen; one of the
double-image-micrometers seems to have failed; and the
Zenith-telescope gives some trouble. At three stations at Rodriguez,
and three at Kerguelen, the observations appear to have been most
successful. At the Sandwich Islands, two of the stations appear to
have been perfectly successful (except that I fear that the Janssen
has failed), and a rich series of lunar observations for longitude is
obtained. At New Zealand, I grieve to say, the observations were
totally lost, entirely in consequence of bad weather. There has been
little annoyance from the dreaded 'black drop.' Greater inconvenience
and doubt have been caused by the unexpected luminous ring round
Venus.--With regard to the progress of my proposed New Lunar Theory:
Three computers are now steadily employed on the work. It will be
remembered that the detail and mass of this work are purely numerical;
every numerical coefficient being accompanied with a symbolical
correction whose value will sometimes depend on the time, but in every
case is ultimately to be obtained in a numerical form. Of these
coefficients, extracted (for convenience) from Delaunay's results,
there are 100 for parallax, 182 for longitude, 142 for latitude; the
arguments being preserved in the usual form."--After reviewing the
changes that had taken place at the Observatory during the past forty
years, the Report to the Board of Visitors concludes thus: "I much
desire to see the system of time-signals extended, by clocks or daily
signals, to various parts of our great cities and our dockyards, and
above all by hourly signals on the Start Point, which I believe would
be the greatest of all benefits to nautical chronometry. Should any
extension of our scientific work ever be contemplated, I would remark
that the Observatory is not the place for new physical investigations.
It is well adapted for following out any which, originating
with private investigators, have been reduced to laws susceptible
of verification by daily observation. The National Observatory
will, I trust, always remain on the site where it was first
planted, and which early acquired the name of 'Flamsteed Hill.'
There are some inconveniences in the position, arising principally
from the limited extent of the hill, but they are, in my opinion, very
far overbalanced by its advantages."--In a letter on the subject of
the Smith's Prizes Examination at Cambridge, which was always a matter
of the greatest interest to him, Airy renewed his objections to the
preponderance in the Papers of a class of Pure Mathematics, which he
considered was never likely under any circumstances to give the
slightest assistance to Physics. And, as before, these remarks called
forth a rejoinder from Prof. Cayley, who was responsible for many of
the questions of the class referred to.--In this year Airy completed
his "Notes on the Earlier Hebrew Scriptures," which were shortly
afterwards published as a book by Messrs Longmans, Green, & Co. In his
letter to the publishers introducing the subject, he says, "For many
years past I have at times put together a few sentences explanatory as
I conceive of the geographical and historical circumstances connected
with the principal events recorded in the Hebrew Scriptures. The view
which I take is free, but I trust not irreverent. They terminate with
a brief review of Colenso's great work. The collection now amounts to
a small book." From the references already given in previous years to
his Papers and correspondence on the geography of Exodus, his
correspondence with Colenso, &c. &c., it will be seen that he took a
great interest in the early history of the Israelites.--On August
10th, 1875, Airy celebrated the Bicentenary of the Royal Observatory
by a dinner in the Octagon Room, which was attended by the Presidents
of the Royal Society and the R. Astr. Society, and by a large number
of Scientific gentlemen interested in Astronomy.--In February he was
revising his Treatise on "Probabilities."
Of private history: up to Jan. 16th Airy was at Playford as
usual.--For about a week in April he was in the Isle of Man with his
daughter Christabel.--In June there was a short trip to Salisbury,
Blandford, and Wimborne.--On August 12th he started with his daughter
Annot for a holiday in Cumberland, but on the next day he was recalled
by a telegram with the intelligence that a change for the worse had
come over his wife's health. Lady Airy died on August 13th, 1875. For
the last five years of her life she had been very helpless from the
effects of a paralytic stroke--a very sad ending to a bright and happy
life--and had been continually nursed throughout this time by her two
unmarried daughters with the greatest self-denial and devotion. Her
husband had been unremitting in his care and attention. Nothing was
wanting that the most thoughtful kindness could supply. And in all his
trips and excursions his constant and kind letters shewed how anxious
he was that she should participate in all his interests and
amusements. From the nature of the case it could hardly be said that
her death was unexpected, and he received the shock with the manly
steadiness which belonged to him. Lady Airy was buried in Playford
churchyard.--From Sept. 22nd to Oct. 4 he made a short expedition to
Wales (Capel Curig, &c.).--On Dec. 15th he attended the Commemoration
at Trinity College, Cambridge.--On Dec. 22nd he went as usual to
Playford.
In this year Airy received the high honour of the Freedom of the City
of London, in the following communication:
STONE, Mayor.--A Common Council holden in the Chamber of the Guildhall
of the City of London, on Thursday the 29th day of April 1875.
Resolved Unanimously
That the Freedom of this City in a Gold Box of the value of One
hundred guineas be presented to Sir George Biddell Airy, K.C.B.,
D.C.L., LL.D. &c., Astronomer Royal, as a recognition of his
indefatigable labours in Astronomy, and of his eminent services in the
advancement of practical science, whereby he has so materially
benefited the cause of Commerce and Civilization.
MONCKTON.
This Resolution was forwarded with a letter from Benjamin Scott, the
Chamberlain. Airy's reply was as follows:
ROYAL OBSERVATORY, GREENWICH, S.E.
_1875, May 1_.
DEAR SIR,
I have the honour to acknowledge your letter of April 30, accompanied
with Copy of the Resolution of the Common Council of the City of
London passed at their Meeting of April 29, under signature of the
Town Clerk, That the Freedom of the City of London in a valuable Box
be presented to me, in recognition of works stated in the
Resolution. And I am requested by you to inform you whether it is my
intention to accept the compliment proposed by the Corporation.
In reply, I beg you to convey to the Right Honorable the Lord Mayor
and the Corporation that I accept with the greatest pride and pleasure
the honour which they propose to offer to me. The Freedom of our Great
City, conferred by the spontaneous act of its Municipal Governors, is
in my estimation the highest honour which it is possible to receive;
and its presentation at this time is peculiarly grateful to me.
I have the honour to be,
Sir,
Your very obedient servant,
G.B. AIRY.
_Benjamin Scott, Esq.,
&c. &c. &c.
Chamberlain of the Corporation of the
City of London._
As it was technically necessary that a Freeman of the City of London
should belong to one or other of the City Companies, the Worshipful
Company of Spectacle Makers through their clerk (with very great
appropriateness) enquired whether it would be agreeable that that
Company should have the privilege of conferring their Honorary Freedom
on him, and added: "In soliciting your acquiescence to the proposal I
am directed to call attention to the fact that this Guild is permitted
to claim all manufacturers of Mathematical and Astronomical
Instruments within the City of London, which is now pleaded as an
apology for the wish that one so distinguished as yourself in the use
of such Instruments should be enrolled as a Member of this Craft." In
his reply, accepting the Freedom of the Company, Airy wrote thus: "I
shall much value the association with a body whose ostensible title
bears so close a relation to the official engagements which have long
occupied me. I have had extensive experience both in arranging and in
using optical and mathematical instruments, and feel that my own
pursuits are closely connected with the original employments of the
Company." The Freedom of the Company was duly presented, and the
occasion was celebrated by a banquet at the Albion Tavern on Tuesday,
July 6th.
The Freedom of the City of London was conferred at a Court of Common
Council held at the Guildhall on Thursday the 4th of November. In
presenting the gold box containing the Freedom, the Chamberlain, in an
eloquent speech, first referred to the fact that this was the first
occasion on which the Freedom had been conferred on a person whose
name was associated with the sciences other than those of war and
statecraft. He then referred to the solid character of his work, in
that, while others had turned their attention to the more attractive
fields of exploration, the discovery of new worlds or of novel
celestial phenomena, he had incessantly devoted himself to the less
interesting, less obtrusive, but more valuable walks of practical
astronomy. And he instanced as the special grounds of the honour
conferred, the compilation of nautical tables of extraordinary
accuracy, the improvement of chronometers, the correction of the
compasses of iron ships, the restoration of the standards of length
and weight, and the Transit of Venus Expeditions. In his reply Airy
stated that he regarded the honour just conferred upon him as the
greatest and proudest ever received by him. He referred to the fact
that the same honour had been previously conferred on the valued
friend of his youth, Thomas Clarkson, and said that the circumstance
of his succeeding such a man was to himself a great honour and
pleasure. He alluded to his having received a small exhibition from
one of the London Companies, when he was a poor undergraduate at
Cambridge, and acknowledged the great assistance that it had been to
him. With regard to his occupation, he said that he had followed it in
a great measure because of its practical use, and thought it fortunate
that from the first he was connected with an institution in which
utility was combined with science. The occasion of this presentation
was celebrated by a Banquet at the Mansion House on Saturday July 3rd,
1875, to Sir George Airy (Astronomer Royal) and the Representatives of
Learned Societies.
There is no doubt that Airy was extremely gratified by the honour that
he had received. It was to him the crowning honour of his life, and
coming last of all it threw all his other honours into the shade. To
his independent and liberal spirit there was something peculiarly
touching in the unsolicited approbation and act of so powerful and
disinterested a body as the Corporation of the City of London.