WRITINGS AND EXPERIMENTAL INVESTIGATIONS.
Could the whole of Sir John Herschel’s astronomical career be
obliterated, and the whole of his contributions to pure mathematics be
forgotten, he would still merit celebrity as a physicist. Experimental
optics, above all, engaged his attention. “Light,” he himself said,
“was his first love,” and he was never wholly forgetful of it. In 1830
he described himself as “forcibly drawn aside from his optical studies”
by the claims of nebulæ and double stars. How strong he felt those
claims to be, can best be understood by considering the firmness with
which he averted his mind, out of regard to them, from the intricate
and bewitching subject of his early devotion.
“I understand from Peacock,” Dr. Whewell wrote to him, June 19, 1818,
“that you are untwisting light like whipcord, examining every ray that
passes within half a mile, and putting the awful question, ‘Polarised,
or not polarised?’ to thousands that were never before suspected of any
intention but that of moving in a straight line.” These interrogatories
brought out a remarkable diversity in the action upon light of quartz,
and other similar substances, corresponding with the two different
modes of crystallisation belonging to each of them. Here, in Lord
Kelvin’s phrase, is “one of the most notable meeting-places between
natural history and natural philosophy.”
The nascent science of spectrum analysis was materially promoted by
Herschel. He noticed in 1819 the distinctive light-absorbing qualities
of coloured media, studied the spectra of various flames, adverted
to the definiteness and individuality of the bright lines composing
them, and recommended their employment for purposes of chemical
identification.
A year later, he developed and modified Brewster’s explanation of the
colours of mother-of-pearl. They do not, like the iridescence of a
fly’s wing, result from the interference of waves of light reflected
from two closely adjacent surfaces, but from interference brought about
by the finely striated texture of the shell’s surface, and a cast of
the rainbow-tinted surface in black sealing-wax will display the same
sheen of colour as the original. Herschel detected, however, a second
more closely striated structure which cannot be impressed upon plastic
matter.
Up to this time he accepted unreservedly the emission theory of
light. But a candid study of Young’s and Fresnel’s writings produced
a fundamental change in his opinions; and in an article on “Light,”
written for the “Encyclopædia Metropolitana” in 1827, he expounded
the undulatory theory with all the ardour of a neophyte. He brought
thereby one of the grandest generalisations of science into universal
currency, and enforced its acceptance by the cogency of his
arguments, the logical order of his method, and the lucidity of his
style. The treatise was translated into French by Quetelet; and no
reader, Professor Pritchard remarked, “could escape the charm of the
half-suppressed enthusiasm which carried him along.”
Whewell ranked him “among the _very_ small number of those who, in the
singularly splendid and striking researches of physical optics, had
both added important experimental laws to those previously known, and
weighed the relations of these discoveries to the refined and recondite
theory towards which they seemed to point.” He contributed to the
same Encyclopædia scarcely less brilliant essays on Heat, Sound, and
Physical Astronomy.
“Do not observe too much in cold weather,” Miss Herschel advised her
nephew, in anticipation of the winter of 1831–2; “write rather books to
make folks stare at your profound knowledge.”
He followed the positive part of her counsel. Indeed, his “Preliminary
Discourse on the Study of Natural Philosophy” had made its appearance
in the previous year, as the introductory volume to Lardner’s “Cabinet
Cyclopædia.” It was greeted with a chorus of approbation. Gauss
reviewed it in the _Gelehrte Anzeigen_, Whewell in the _Quarterly
Review_. Translated into French, German, and Italian, it delighted
“all sorts and conditions” of readers with the justice and breadth of
the views set forth in it agreeably, easily, and without pretension
to superiority. The book included a survey of the actual state
of scientific knowledge, and a philosophy of its augmentation.
Students derived from it, Gauss remarked, both information as to how
accepted results had been obtained, and guidance for their personal
investigations. Herschel was exceptionally qualified, Whewell wrote,
“to expound the rules and doctrines of that method of research to which
modern science has owed its long-continued, steady advance, and present
flourishing condition.” He had the knowledge, without the narrowness,
of a specialist in almost every department of experimental physics.
“With singular alacrity,” he came to the front wherever there seemed a
chance of pushing back the barriers of ignorance. A disciple of Bacon,
he had the advantage over his master of being habitually conversant
with the practical working of inductive methods. The treatise was
styled by Whewell “an admirable comment on the ‘Novum Organum.’” One,
however, possesses the indefinable quality of _greatness_; it stands
out from the centuries a solid structure, clothed with visionary
magnificence; the other is elegant, attractive, wise, acute, even
profound, but not in any degree, or from any point of view, _great_.
It was followed, in 1833, by “A Treatise on Astronomy,” published in
the same series. An “Edinburgh Reviewer” (doubtless Brougham once more)
perused it with regret. “The proper position of Sir John Herschel” he
considered to be “at the head of those who are nobly, though it may
be silently and without notice, endeavouring to extend the present
limits of human knowledge,” rather than among “the ranks of those whose
office it is to herald the triumphs of science, and point out its
treasures and results to the admiration of the vulgar.” This ostensibly
flattering estimate was made the basis for an imputation of vanity. The
inducements, according to the critic, were strong “to descend from the
airy summits of abstract science to the level at which the great body
of the reading public can appreciate and applaud. Philosophers, like
other writers, naturally wish to be read, and to have reputation; and
reputation, as was remarked by d’Alembert, depends more upon the number
than the merit of those who praise.” Sir John Herschel would have been
better employed in pursuing the track of original discoveries, leaving
new truths to “find their way to the drawing-room as best they might.”
The whole tenour of his life refuted these insinuations.
The “Treatise on Astronomy” was enlarged in 1849 into the deservedly
famous “Outlines of Astronomy.” Twelve editions of this book were
published, the last in 1873; it was translated into Chinese and Arabic,
as well as into most European languages, including Russian; it made a
profound and lasting impression upon the public mind. No science has
perhaps ever received so masterly a general interpretation. Methodical
in plan, inspiriting in execution, it demands readers willing to share
some part of the pains, for the sake of partaking in the high pleasures
of the writer. For it is popular in the sense of eschewing mathematical
formulæ, not in the sense of evading difficulties.
The work fittest to be set by its side is the “Exposition du Système
du Monde.” But Laplace restricted his view to the sun’s domain, while
Herschel excluded from his no part of the sidereal universe. Laplace
was, besides, a geometer in the first, an astronomer only in the second
place. The movements of the heavenly bodies interested him because
they afforded opportunities for analytical triumphs. Their intricacy
notwithstanding, he was elated to find that they could not baffle his
ingenuity in constructing formulæ to correspond. Their balance, their
harmony, their obedience to a single and simple law, gratified the
orderly instincts of his powerful yet frigid mind. Where he could not
explain, however, he did not admire. Mystery had no attraction for
him. Knowledge, to _be_ knowledge in his eyes, should have definite,
clear-cut outlines. His scheme of the universe was like the map of the
world laid down by Hecatæus, neatly finished off with a circumfluent
ocean-stream; it included no intimations of a _beyond_. Herschel’s, on
the contrary, might be compared to the map of Herodotus, in which some
details were filled in, while the external boundary had been abolished.
The most essential part of the progress made in the interval consisted
in leaving verge and scope for the unknown. Next to nothing remained
to be learned of the heavens, as they presented themselves to the
author of the “Mécanique Céleste”; while Herschel saw everywhere only
beginnings, possibilities of discovery, and dim prospects of “ultimate
attainments,” as to the realisation of which “it would be unwise to be
sanguine, and unphilosophical to despair” (Playfair). At the head of
very many of his chapters he might, without presumption, have written:
“Quorum pars magna fui.” They gave largely the results of his personal
investigations, and were vivified by immediate acquaintanceship
with the objects described. Hence the unsought picturesqueness of
his descriptive epithets, and the sublimity of trains of thought
communicated to him direct from the unveiled heavens.
Herschel invented in 1825, jointly with Babbage, the “astatic,” or
neutralised magnetic needle--a little instrument which was no sooner
available than it was found to be indispensable. “Nihil tetigit
quod non ornavit.” And many and various were the things touched by
his versatile genius. He had a narrow escape of becoming for life a
chemist. At the very outset of his career he applied for the vacant
chair of that science at Cambridge; but was left, as he himself
humorously expressed it, “in a glorious minority of one.” The chemical
inquiries, nevertheless, which he carried on at Slough brought to
his notice one set of relations of no trifling importance. This was
the solvent effect upon salts of silver of the hyposulphites of soda,
potash, etc. The discovery was turned to account by himself in 1840
for the “fixing” of photographic images. It secured the future of the
embryo art. By the agency of hyposulphite of soda in washing away the
unaffected chloride of silver, while leaving untouched the parts of the
deposit decomposed and darkened by exposure, permanent light-pictures,
capable of indefinite multiplication, were at length secured.
On March 14th, 1839, unaware that he had been anticipated by Fox
Talbot, Herschel presented to the Royal Society twenty-three prints
made by the sensitised paper process. A memoir communicated in 1840
was full of suggestive novelties. In it he described experiments on
“the chemical analysis of the solar spectrum,” pointing out that the
character and amount of the action exercised by the various rays
depend mainly upon the nature of the substance acted upon. He made
a start, too, with spectral photography, and his detection of the
“lavender-grey” effect to the eye of the ultra-violet section might
be said to have added a new note to the prismatic gamut. In the
opposite, or infra-red end, by simply letting the solar spectrum fall
upon a strip of paper moistened with alcohol, he detected, through the
different rates of drying where they fell, some of the “cold bands,”
by which the invisible heat-rays are furrowed. The photo-spectroscopic
apparatus devised for the purpose of these researches formed part
of the Loan Collection of Scientific Instruments exhibited at South
Kensington in 1876.
Still more essential was the improvement of substituting for paper,
glass plates spread with a sensitive film. A photograph of the old
forty-foot telescope, taken by this method in 1839, and preserved in
the South Kensington Museum, is of unrivalled antiquarian value as
regards the history of photography. The terms “positive” and “negative”
received in this remarkable paper their now familiar photographic
meaning. Its merits were acknowledged in 1840 by the award of a Royal
Medal.
Sir John Herschel would, doubtless, at that time have set aside as
a chimera the notion that the art he was engaged in promoting was
destined, in large measure, to supersede visual methods in astronomy;
that the great telescopes of the future would find their most useful
employment in concentrating the rays of celestial objects upon
sensitive plates. He soon perceived, however, the importance of
photography as an adjunct to direct observation, and recommended,
in 1847, the automatic self-registration of sun-spots. This
hint--emphasised in 1848--was acted upon in 1858, when the regular
collection of documentary evidence as to the sun’s condition was begun
at Kew with De la Rue’s “photoheliograph.”
In 1845 he published the first effective investigation of
“fluorescence,” called by him “epipolic,” or superficial, “dispersion.”
This curious phenomenon consists in the illumination to the eye of
certain substances, such as sulphate of quinine and canary glass,
under the play of _invisible_ light. Sir George Stokes showed in 1852
that the impinging rays have their undulations actually lengthened by
the action of such kinds of matter, so as to become degraded in the
spectrum, and thus brought within the range of vision.
The Herschelian theory of the sun was adopted, and long retained by
Sir John. He believed in a cool, solid interior globe sheltered by
a succession of aërial envelopes, rent, locally and temporarily,
by tornadoes of fire. The presence of inhabitants on the globe so
circumstanced was credible to him, although he abstained from dwelling
upon the advantages of their state. He carefully followed, however, the
progress of solar science, and in 1864 explained his altered views in
the _Quarterly Journal of Science_. He now regarded the sun as a wholly
gaseous mass--a conclusion in which he was anticipated only by Father
Secchi. He added that it must be largely composed of matter kept in an
intermediate condition between liquid and vaporous by “high temperature
and enormous pressure.” The spot-period, he suggested, might be that of
a revolving meteoric ring with condensations.
He was vividly interested in the “willow-leaf” controversy, raised in
1862 by Nasmyth’s misinterpreted observations. The objects seen were
simply Sir William Herschel’s “nodules”--the luminous elements of the
sun, held by Sir John in 1867 “to be permanently solid matter, having
that sort of fibrous or filamentous structure which fits them, when
juxtaposed by drifting about, and jostling one against another, to
collect in flocks as _flue_ does in a room.” He concluded with the
remarkable assertion that the sun has no real surface, “the density
diminishing from that below the photosphere to _nil_ in the higher
regions, where the pressure is _nil_.”
Herschel’s “Cape Observations” stands alone in astronomical literature
for the wide and permanent interest of its contents. They are
exceedingly various. Chapters on Halley’s Comet, on Sun-spots, the
Satellites of Saturn, Astrometry, the Constitution of the Southern
Galaxy, are associated with discussions on the nature and distribution
of nebulæ, with monographs of two, and incidental notes on many of
these enigmatical objects. The volume is illustrated with over sixty
beautiful steel engravings of nebulæ and clusters, of sun-spots, and of
the comet.
The speculations it includes regarding the nature of nebulæ, deserve
even now to be remembered. Sir John was, at the outset, an unwavering
adherent of the theory developed by his father in 1811. They were
composed, he held in 1825, of a “self-luminous; or phosphorescent
material substance, in a highly dilated or gaseous state, but gradually
subsiding, by the mutual gravitation of its molecules, into stars
and sidereal systems.” His personal experience, however, ran counter
to this view. In 1833 he had become convinced that a nebula is, in
general, “nothing more than a cluster of discrete stars.”
The successful resolution into stars, with the great Parsonstown
specula, of many nebulæ until then called irresolvable, carried him
still further in the same direction. To him, as to other thinkers,
the presence in space of a self-luminous cosmic fluid became more
than doubtful. In his Presidential Address to the British Association
in 1845, he dwelt with enthusiasm on the completion of the Rosse
reflector--“an achievement of such magnitude, that I want words to
express my admiration of it.” He regarded “as one of the grand fields
open for discovery with such an instrument, those marvellous and
mysterious bodies, or systems of bodies, the nebulæ.” Their frequent
resolution, actual or indicated, with increased optical power, led
him to attribute recalcitrance in this respect to the smallness and
closeness of the stars of which they consist; he held them, in short,
to be “optically, and not physically, nebulous.”
A new consideration was thus introduced into discussions on nebulæ. The
whole burthen of accounting for their varieties in telescopic aspect
need no longer be thrown upon differences of remoteness; diversities
in the size and closeness of nebular _molecules_ would answer the same
purpose. So that pulverulent agglomerations, it was thought, might pass
by insensible gradations into collections of truly sun-like bodies. All
distinction between nebulæ and clusters was then abolished, the members
of both classes consisting, like the sun’s photosphere, of shining
granules, supported in an obscure medium, varying in real magnitude
from _floccules_ to great globes, while each vast compound body rotated
_en masse_ on an axis. Whatever the merits of this scheme, it at least
harmonises with the now prevalent opinion that nebulæ and clusters
belong to one unbroken cosmical series. “They are divided,” Mr. Cowper
Ranyard wrote in 1893, “by no hard and fast line. The larger nebulæ may
be described as groups of stars surrounded by bright nebulosity, and
star-clusters as groups of stars surrounded by faint nebulosity.”
Herschel’s assimilation of nebulæ to clusters was not meant to apply
to “those extraordinary objects resembling the wisps and curls of a
cirrous cloud,” which confront the astronomer in Orion, Argo, and
elsewhere. “The wildest imagination,” he said, “can conceive nothing
more capricious than their forms. With their resolution,” he averred,
“and that of elliptic nebulæ, the idea of a nebulous matter, in the
nature of a shining fluid or condensible gas, would cease to derive
any support from observation.” He, in fact, discarded it absolutely on
the deceptive analysis into stars at Parsonstown and Harvard College
of the Orion and Andromeda nebulæ. The discredited hypothesis was
nevertheless triumphantly reinstated by Dr. Huggins’s spectroscopic
observations in 1864.
One-third of the whole nebular contents of the heavens Herschel found
to be collected into a broad, irregular patch, the central point of
which in Virgo coincides almost precisely with the northern pole of
the Milky Way. He compared it to a canopy surmounting the galactic
zone. In the other hemisphere the arrangement, although less distinctly
characterised, is on the same general plan. Plainly, then, nebular
distribution has an opposite correspondence with stellar distribution,
and the two partial systems are complementary one to another, Herschel,
however, contented himself with the somewhat ambiguous statement that
“the nebulous system is distinct from the sidereal, though involving
and, to a certain extent, intermixed with it.”
His verdict as to the ground-plan of the sidereal edifice might be
summed up in the phrase, “Not a stratum, but an annulus,” our own
situation being in a relatively vacant interior space. Hence, the sun
belongs, not to the Milky Way proper--as it should on the stratum
theory--but to the system of which the Milky Way forms part. This
conclusion was in itself a distinct advance towards the solution of an
exorbitantly difficult problem. The grand question as to the remoteness
of the star-clouds in that gleaming sky-girdle was definitely raised
by it; and the question is not, in the nature of things, unanswerable.
Herschel’s annulus was not a neat structure with a cylindrical
section, but “a flat ring, or some other re-entering form of immense
and irregular breadth and thickness.” It is cloven over one-third of
its circumference; it is interrupted by huge chasms; it is bent, and
shattered and broken, and probably set with tentacular appendages,
giving rise, by their foreshortening, to very complex visual effects.
All of which modifying circumstances Herschel implicitly recognised.
He was the first to gather any direct intimations of the existence
of that “solar cluster” which, guessed at by the elder Herschel, has
of late assumed a sort of elusive reality. A zone of bright stars,
including those of Orion, Canis Major, the Ship, the Cross, and the
Centaur, struck him at once as a conspicuous feature in the scenery of
the southern heavens. Its aspect led him to “suspect that our nearest
neighbours in the sidereal system form part of a subordinate sheet, or
stratum,” inclined at an angle of twenty degrees to the plane of the
Milky Way. To Dr. Gould at Cordoba, in 1879, “few celestial phenomena”
appeared “more palpable” than this projected star-belt; and, since
it traces out a great circle on the sphere, the sun must be placed
within it, and pretty accurately in its plane; yet the difficulty
of associating it intimately with our particular star seems all but
insurmountable.
Herschel’s minor and occasional writings were neither few nor
unimportant. He contributed articles on “Isoperimetrical Problems”
and “Mathematics” to Brewster’s _Edinburgh Cyclopædia_, and on
“Meteorology,” “Physical Geography,” and “The Telescope,” to the
eighth edition of the _Encyclopædia Britannica_. These last were
printed separately as well. He edited in 1849 the Admiralty “Manual
of Scientific Inquiry,” and criticised in the _Edinburgh_ and
_Quarterly Reviews_ Mrs. Somerville’s “Mechanism of the Heavens,”
Whewell’s “History of the Inductive Sciences,” Humboldt’s “Kosmos,”
and Quetelet’s “Theory of Probabilities.” His addresses as President
of the Royal Astronomical Society were models of their kind, and the
same might be said of his memoirs of Baily and Bessel in the “Monthly
Notices.” Most of them were collected in 1857, with his review
articles, into a volume of “Essays;” and his attractive “Familiar
Lectures on Scientific Subjects,” published in 1867, gave permanence to
some popular discourses delivered in the school-house of Hawkhurst, as
well as to articles from _Good Words_ on Light and other subjects. No
less than 152 papers by him are included in scientific repertories.
He had a considerable faculty for translating poetry, and its exercise
made one of his favourite recreations. Having adopted the literal
theory of the art, he kept strictly to the original metres, and thus
fettered, got over the ground with more grace and ease than might have
been expected. His first attempt with English hexameters was in a
version of Schiller’s “Walk,” privately printed in 1842. He had come
to love the poem through its association in his mind with a favourite
stroll up the side of Table Mountain; and a translation of it in the
_Edinburgh Review_ leaving, as he thought, something to be desired,
he tried his hand, and distributed the result “among his friends as
his Christmas sugar plum.” The various acknowledgments made an amusing
collection. One lady said that she “found it difficult to get into the
_step_ of the _Walk_.” Another correspondent declared that the _Walk_
had got into a _Run_ through ceaseless borrowing. A third qualified his
encomium upon the ideas by adding, “To the _verse_ I am _averse_.”
Joanna Baillie, however, and her sister were delighted with both the
substance and form of the poem, and it was included among Whewell’s
“English Hexameter Translations” in 1847.
His success encouraged him, after twenty years, to undertake an
indefinitely more difficult task. Pope’s Iliad he described happily as
“a magnificent adumbration” of the original; but he aimed rather at
producing a “fac-simile,” in
“Hexameters no worse than daring Germany gave us.”
His version should come as near as he could bring it to a photograph
of a grand piece of architecture; and as a measure of its fidelity, he
printed in italics all the words _not_ in the text. Whewell remarked
that it was “curious to see how few he had managed to make them,” and
preferred his translation to any other with which he was acquainted.
But English hexameters were a hobby of the Master of Trinity, who
accordingly viewed with partiality what Tennyson called the “burlesque
barbarous experiment” of thus lamely rendering “the strong-wing’d music
of Homer.”
De Morgan, too, was one of the “averse.” “Many thanks for the
hexameters,” he wrote, on receiving an instalment of the Collingwood
Iliad; “they are as good as they can be, but all the logic in the
world does not make me feel them to be English metre, and they give
satisfaction only by reminding one of the Greek: just as, mark you,
a flute-player--which I have been these forty-five years--only plays
Haydn and Mozart because he has the assistance of the orchestral
accompaniment which arises in his head with the melody. The hexameter,
it is clear, does not fix itself in the popular mind. The popular mind
knows neither quantity nor accent, but that which is to last bites its
own way in, without any effort.”
Yet Herschel’s translation is not without merit. It is disfigured
neither by affectation nor by magniloquence, and it catches here and
there something of the greatness of the unapproached original. Let us
take two specimens; this from the “Shield of Achilles”:--
“There he depicted the earth, and the canopied sky, and the ocean;
There the unwearied sun, and the full-orb’d moon in their courses.
All the configured stars, which gem the circuit of heaven,
Pleiads and Hyads were there, and the giant force of Orion.
There the revolving Bear, which the Wain they call, was
ensculptured,
Circling on high, and in all its course regarding Orion;
Sole of the starry train which refuses to bathe in the Ocean.”
The next likewise appeals to the astronomer. It is the famous simile
from the end of the Eighth Book:--
“As when around the glowing moon resplendent in ether,
Shines forth the heavenly host, and the air reposes in stillness;
Gleams every pointed rock, stands forth each buttress in prospect;
Shimmers each woodland vale; and from realms of unspeakable glory
Op’ning, the stars are revealed; and the heart of the shepherd
rejoices.
Such, and so many the fires, by the Trojans kindled, illumined
Eddying Xanthus’ stream, and the ships, and the walls of the city.”
Sir John Herschel corresponded with Mr. Proctor, during the last two
years of his life, on the subject of sidereal construction; and his
replies to the arguments put before him show that his mind retained,
even then, its openness and flexibility. He had none of the contempt
for speculative excursions which sometimes walls up the thinking-powers
of observers. “In the midst of so much darkness,” he held that “we
ought to open our eyes as wide as possible to any glimpse of light,
and utilise whatever twilight may be accorded us, to make out, though
but indistinctly, the forms that surround us.” “_Hypotheses fingo_ in
this style of our knowledge,” he went on, “is quite as good a motto
as Newton’s _non fingo_--provided always they be not hypotheses as to
modes of physical action for which experience gives no warrant.” And
again: “We may--indeed, must--form theories as we go along; and they
serve as guides for inquiry, or suggestions of things to inquire; but
as yet we must hold them rather loosely, and for many years to come
keep looking out for side-lights.”
These were his last words on the philosophy of discovery: and they
constituted his last advice to scientific inquirers. But, good as
were his precepts, his example was better. There was no discrepancy
between his work and his thought. Both combined to inculcate aloofness
from prejudice, readiness of conviction in unequivocal circumstances,
suspension of judgment in dubious ones, and in all, candour, sobriety,
and an earnest seeking for truth.
INDEX.
Actinometer, J. Herschel’s, 152, 179, 180
Adams, J. C., at Collingwood, 188
Ages of heavenly bodies, 68, 94, 170
Alexander, the Czar, 49
Amici, of Modena, 148, 150
Apertures, method of, 61, 63
Apex, solar, 78, 80
Archbishop of Canterbury, and George III., 38
Argelander, 80, 106
Asteroids, 46, 90–1, 95, 100
Astrometer, J. Herschel’s, 177
Astronomical Society, 49, 152, 188
Aubert, Alexander, 16, 101, 124
Babbage, companionship with J. Herschel, 143–4, 149, 152;
astatic needle, 208
Bailey, S. I., 169, 170
Baily, Francis, 164, 185, 186, 187
Barnard, diameters of asteroids, 91;
nebulosities, 110–11;
photographs of Milky Way, 174
Bates, Joah, anecdote of W. Herschel, 12
Bath, centre of fashion, 12;
Herschel’s residences there, 17, 26, 47
Beckedorff, Mrs., 126, 127, 160;
Miss, 138
Bessel, solar movement, 80;
estimate of W. Herschel, 109;
Halley’s comet, 177;
at Collingwood, 187;
memoir of, 216
Biot, estimate of J. Herschel, 201
Bonaparte, Lucien, 33, 44
Bonaparte, Napoleon, Herschel’s interview with, 47
Bradley, observation of Castor, 76
Brougham, Lord, 53, 88, 90, 207
Burney, Dr., notices of W. Herschel, 12, 44, 45–6;
walk through forty-foot, 38;
notices of Caroline and J. Herschel, 125, 142
Burney, Miss, meetings with W. Herschel, 38–9;
with Mrs. and Miss Herschel, 44, 124, 125, 127
Burnham, double stars, 103;
planetary nebulæ, 155
Campbell, Thomas, admiration for W. Herschel, 47–8;
notice of his son, 145
Cavendish, anecdote of, 100
Clay Hall, 36
Climate, changes of, 82
Comet, of October 1806, 48;
of 1811, 94;
Encke’s, 124, 175;
of 1819, 128–9;
Biela’s, 153;
Halley’s, 175–6, 180, 211
Comets, decay of, 94;
Miss Herschel’s, 124, 125
Common, Dr., five-foot reflector, 99
Construction of the Heavens, 53, 60, 113–114, 214–15
Dante and the “Divina Commedia,” 15
Datchet, house at, 32, 36
Dawes, sun-spot nuclei, 83
De la Rue, photoheliograph, 210
De Morgan, letter to Captain Smyth, 188–9;
Herschel and the coinage, 191;
friendship with, 197;
dislike to hexameters, 217
Dreyer, Catalogue of Nebulæ, 192
Easton, Milky Way structure, 106
Edgeworth, Miss, at Slough and Collingwood, 192–3
Feldhausen, 163, 180, 181
Flamsteed, British Catalogue, 80, 123, 126
Galileo, double-star method of parallaxes, 55
Gauss, 151, 201, 205
George III., patronage of Herschel, 10, 24, 28–9, 30, 32, 33;
taste for astronomy, 30, 47;
walk through great telescope, 38
Gill, Dr., Herschel’s micrometers, 103;
photographic catalogue, 106;
photographs of Argo nebula, 167;
of Omega Centauri, 169
Gordon, Lady, portrait of Sir J. Herschel, 202
Gould, Dr., solar cluster, 107, 215
Grahame, James, 149
Gravitation, extension of to stellar systems, 77, 148
Gregorian reflectors, 20, 29
Griesbach, Mrs., 10, 116;
her sons, 10, 28, 29
Halley, list of nebulæ, 19;
stellar motions, 77
Hamilton, Sir W. R., communications with J. Herschel, 146, 152,
158, 173, 188;
speech by, 182;
at Collingwood, 193;
quaternions, 194–5
Haydn, visit to Slough, 44
Heat-rays in solar spectrum, 95–6
Herschel, Alexander, assisted his brother, 13, 21, 27, 120;
accompanied him to Göttingen, 37;
supported by him, 51;
care for his sister, 118
Herschel, Professor Alexander, meteoric researches, 201
Herschel, Caroline, fetched to Bath, 15, 118;
help in speculum making, 15, 20, 124;
a singer, 21, 117, 119;
remarks, 25, 27, 34, 49;
letters from W. Herschel, 28, 29, 30, 129;
household cares, 32, 118, 121;
reminiscences, 35, 36, 37, 39, 48, 50, 68;
annuity, 51, 131;
birth and childhood, 115–16;
education, 115, 118, 121;
visits to London, 121, 127;
discoveries of nebulæ, 122;
of comets, 124–5, 139;
her brother’s assistant, 122–3, 125;
catalogues nebulæ, 123, 132;
Index to Flamsteed’s observations, 126;
royal attentions, 126, 127, 133, 135, 139;
anxiety about her brother’s health, 128–9;
return to Hanover, 130–1;
Gold Medals bestowed on, 132, 138;
joy in her nephew’s career, 134–5, 159;
his visits, 135–36, 159;
Recollections and Journals, 137, 138;
death, 139;
personality, 139–41;
anecdotes of J. Herschel’s childhood, 142;
his letters to her, 151, 152, 153, 162–3, 164, 175, 176, 187;
her portrait, 196;
her advice to him, 205
Herschel, Dietrich, 20–1, 51, 127–8, 130, 131
Herschel, Sir John, dismantling of great telescope, 43;
catalogues of nebulæ, 132, 155, 191–2;
visits to Hanover, 135–6, 151, 159–60, 184;
nebular observations, 136, 153, 154–7, 165–7;
Cape Expedition, 135, 159–2, 181–2;
birth and childhood, 142;
university career, 143–5;
medals awarded to, 145, 148, 149, 157, 187, 201;
work on double stars, 134, 146–48, 157;
method for computing orbits, 148–9;
general catalogue, 192;
ascents of Monte Rosa and Etna, 149–50;
explorations in Auvergne, 152;
experiments on solar radiation, 151–2, 179;
visit to Ireland, 152;
cometary observations, 153, 175–6, 180, 189;
telescopes, 153, 158, 164, 183;
discovery of star in Orion-trapezium, 158;
marriage, 159;
Feldhausen, 163, 180–1;
Cape climate, 164;
Magellanic Clouds, 165–6;
Argo nebula, 167;
Eta Argûs, 168–9;
globular clusters, 169–71, 213;
star-gauging, 171–2;
comets, 175–6;
stellar photometry, 177;
solar theory, 178–9, 211;
Saturnian satellites, 180;
magnetic work, 184, 189, 208;
constellational reform, 185;
removal to Collingwood, 186;
Cape Results, 186–7, 211–12;
President Astronomical Society, 188;
Master of the Mint, 190–1;
guests at Collingwood, 188, 193, 195;
sonnet, 194;
family life, 195–6;
death, 197;
powers and character, 198–201;
books, 205–8;
photographic experiments, 209–10;
nature of nebulæ, 212–14;
solar cluster, 215;
poetical performances, 216–18;
philosophy of discovery, 219
Herschel, Colonel John, examination of nebular spectra, 201
Herschel, Isaac, 9, 21, 115, 116
Herschel, Jacob, 116, 117, 128
Herschel, Lady, the elder, 44, 50, 152, 160
Herschel, Lady, the younger, 159, 192, 194, 201
Herschel, Sir William, birth, 9;
musical career, 10–16, 21, 26, 121;
telescope, making, 14–15, 17, 19, 20, 22;
thirty-foot, 26–8,
seven-foot, 28–9;
for sale, 33;
forty-foot, 34, 37, 38, 41–3, 49, 50, 100, 137, 210;
twenty-foot, 35–6, 40, 50;
front-view telescopes, 40, 41, 102, 153;
space-penetrating power of, 61, 98;
reviews of the heavens, 19, 20, 26, 35, 36, 42, 46;
early papers, 22–3;
discovery of Uranus, 24–5, 120;
observations of double stars, 26, 49, 55–6, 75;
interviews with the king, 28–30;
royal astronomer, 30, 32–3;
mode of observing, 30, 122;
discovery of Uranian satellites, 40, 93, 153;
of Saturnian satellites, 41, 43, 92;
marriage, 44;
aversion to poetry, 45–6;
interview with Bonaparte, 47;
observations of comets, 48, 94, 128–9;
failure of health, 49–50, 128–9;
death and character, 51;
construction of the heavens, 53–4, 60, 114;
star distances, 54–5, 57, 60–1, 64, 75;
star-gauging, 57–8, 113;
nature of the Milky Way, 57–9, 62–3;
chasms in, 68;
method of apertures, 61;
catalogues of nebulæ, 64;
varieties, 65;
island universes, 66–7, 72;
development, 67–8;
nebulous fluid, 69–70;
condensation into stars, 71–2, 109;
nebular distribution, 73;
discovery of binary stars, 76–7, 147;
transport of the solar system, 77, 80, 108;
stellar photometry, 80–2, 174–5;
theory of the sun, 83–6, 211;
sun spots and weather, 87–8;
observations of Venus, 88;
of Mars, 89;
of the asteroids, 90;
of Saturn, 91;
law of satellite-rotation, 92;
lunar volcanoes, 93;
detection of infra-red heat-rays, 95–7;
use of high powers, 101–2;
micrometers, 103;
photometric enumeration, 106;
solar cluster, 107–8;
diffused nebulosities, 110–11;
a founder of sidereal astronomy, 112
Herschel, Sir William J., 49, 136, 183, 201
Huggins, Dr., spectra of nebulæ, 109, 214;
of stars, 113
Humboldt, 133, 138, 170, 184
Huygens, improvement of telescopes, 17
Jacob, southern Milky Way, 172
Japetus, rotation of, 92
Jupiter, trade wind theory of, 91;
rotation of satellites, 93
Kapteyn, solar cluster, 107
Knipping, Mrs., 137, 138
Lacaille, southern nebulæ, 19
Langley, bolometer, 95;
atmospheric absorption, 152, 179
Laplace, 18, 47, 91, 201, 207
Lassell, Uranian satellites, 93;
reflectors, 99;
observation of Mimas, 180
Le Verrier, 187, 188
Lexell, orbit of Uranus, 24
Maclear, Sir Thomas, 162, 168, 176, 181
Magellan, Von, accounts of William and Caroline Herschel, 40, 122
Magellanic clouds, 165–6
Magnitudes, stellar, 81, 104–5, 177
Mars, analogy with the earth, 89
Maskelyne, 25, 29, 76
Mayer, Christian, satellite-stars, 75
Mayer, Tobias, solar translation, 77, 78
Michell, revolving stars, 75;
solar group, 107
Micrometer, lamp, 24, 103;
wire, 56, 103
Milky Way, rifts in, 50, 67–8, 173, 175, 215;
structure, 57–59, 62, 173–4, 214–15;
spectral peculiarity, 105;
distance, 106, 173, 214;
splendour in southern hemisphere, 172;
photographic portrayal, 174–5
Miller, Dr., 11, 12
Mitchell, Miss, visit to Collingwood, 195–6
Monck, stellar spectroscopic distribution, 107
Moon, mountains of, 22, 23;
volcanoes, 93–4.
Nasmyth, opinion of J. Herschel, 196–7;
solar willow leaves, 211
Nebula, Orion, 15, 43, 65, 70, 71, 110, 111, 153, 167, 214;
Dumb-bell, 157;
Argo, 167;
Andromeda, 214
Nebulæ, catalogues, 19, 64, 123, 132, 191–2;
discoveries, 35, 64, 122, 165;
nature, 66, 212–4;
development, 67, 69, 109–10;
distribution, 73, 214
Nebulæ, annular, 65, 157, 165
Nebulæ, double, 72, 156
Nebulæ, planetary, 65, 67, 71;
spectrum, 109;
satellites to, 155;
colour, 165
Nebulæ, rifted, 157
Nebular theory, 71–2, 109
Newton, law of gravitation, 17, 77;
reflectors, 20, 23;
mode of investigation, 23, 206
Olbers, origin of asteroids, 90;
comet of 1819, 129;
light extinction, 174;
visit from J. Herschel, 184
Orange, Prince of, enquiries at Slough, 39
Papendick, Mrs., remarks on William and Caroline Herschel, 39, 44, 125
Peacock, Dean, 143, 194, 203
Photography, of stellar spectra, 104, 107;
of nebulæ, 110–11, 113, 166–7;
star charting by, 113, 172, 199;
of clusters, 169–70, 171;
of solar spectrum, 209;
of sun-spots, 210
Photometric enumeration, 60, 106, 107, 114;
catalogues, 80
Photometry, stellar, 81, 104, 177;
photographic, 105
Piazzi, visit to Slough, 39, 150
Pickering, E. C. and W. H., photographs of Orion nebula, 111
Pouillet, solar radiation, 179
Pritchard, Dr., 143, 192, 201, 204
Proctor, star-drift, 108;
estimate of Sir J. Herschel, 199, 200;
correspondence with, 218
Ranyard, A. C., changes in nebulæ, 168;
clusters, 213
Roberts, Dr., photographs of nebulæ, 157, 165
Rosse reflector, 99, 212
Russell, H. C., photographs of Magellanic clouds, 166;
of Argo nebula, 167;
of Milky Way, 175
Saturn, artificial, 30;
satellites, 41, 43, 91, 92, 180;
rings, 91–2
Savary, stellar orbits, 148, 149
Schröter, 34, 84, 88–9
Secchi, 113, 211
See, Dr., double nebulæ, 156
Sirius, brilliancy, 42, 168;
standard star, 58, 61, 63, 80
Slough, W. Herschel’s residence at, 36, 44;
birthplace of J. Herschel, 142
Sniadecki, stay at Slough, 39
Solar cluster, 107, 215
Solar radiation, 151–2, 179
Somerville, Mrs., 132
South, Sir James, 146, 147, 149
Spectrum analysis, 84, 204, 209
Spencer, unity of sidereal system, 166
Stanley, Dean, on J. Herschel, 199
Star-clusters, 49, 59, 63, 67, 72, 169–71, 213
Star-gauging, 57–8, 113, 171–2
Stars, binary, 72, 156;
discovery, 76–7, 147;
orbits, 147–9
Stars, double, observations of, 55–6, 103, 146–8, 157;
colours, 56, 112, 156;
nebular relations, 155
Stars, distribution of, 58–9, 60, 73, 81, 106, 171–2
Stars, movements of, 77, 107–8
Stars, nebulous, 69, 70, 71
Stars, spectra of, 83, 105
Stars, spectroscopic binary, 104
Stars, temporary, 66–7
Stars, variable, 23, 81–2, 168–9
Stokes, Sir G., fluorescence, 210
Stone, Herschel’s assistant, 180
Struve, W., 148, 158, 188
Sun, translation, 77–80, 108;
vicissitudes, 82, 87, 88;
constitution, 83–6, 178–9, 211
Sussex, Duke of, 158
Telescopes, Improvement of, 17, 19, 20, 24–6, 33, 36, 98–100
Uranus, discovery of, 24–5, 26, 120;
satellites, 40, 93, 153
Watson, Sir W., 16, 22, 27, 30, 47, 124
Watt, James, 47
Whewell, Dr., unity of sidereal system, 76, 166;
friendship with J. Herschel, 145, 163, 191, 200;
tidal data, 181;
articles in Quarterly Review, 186, 205–6;
Geological Society, 189;
on optical enquiries, 203–4;
hexameters, 217
Wolf, Dr. Max, photographs of nebulæ, 111;
of Milky Way, 175
Wollaston, 145, 177
Worlds, inhabited, 85, 86, 89, 147.
PRINTED BY CASSELL & COMPANY, LIMITED, LA BELLE SAUVAGE PRINTING WORKS,
LONDON, E.C.
Transcriber’s Notes
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