| Day Two: Wednesday Morning, August 26, 1835 |
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Lately Made BY SIR JOHN HERSCHEL, L.L.D, F.R.S, &c. At The Cape of Good Hope. [From Supplement to the Edinburgh Journal of Science] [Continued from yesterday's Sun]
A correspondence had for some time passed between the
Boards of England, France, and Austria, with a view to
improvements in the tables of longitude in the southern
hemisphere; which are found to be much less accurate than
those of the northern. The high opinion entertained by the
British Board of Longitude of the principles of the new
telescope, and of the profound skill of its inventor,
determined the government to solicit his services in
observing the transit of Mercury over the sun's disk, which
will take place on the 7th of November in the present year:
and which, as it will occur at 7h. 57m. 55s. night,
conjunction, meantime; and at 8h. 12m. 22s. middle, true
time, will be invisible to nearly all the northern
hemisphere.
The place at which the transits of Mercury and of Venus
have generally been observed by the astronomers of Europe,
when occurring under these circumstances, si the Cape of
Good Hope; and no transit of Venus having occurred since the
year 1769, and none being to occur before 1874, the accurate
observation of the transits of Mercury, which occur more
frequently, has been found of great importance both to
astronomy and navigation. To the latter useful art, indeed,
the transits of Mercury are nearly as important as those of
Venus; for although those of the latter planet have the
peculiar advantage of determining exactly the great solar
parallax, and thence the distances of all the planets from
the sun, yet the transits of Mercury, by exactly determining
the place of its own node, independently of the parallax of
the great orb, determine the parallax of the earth and moon;
and are therefore especially valuable in solar observations
of Longitude. The Cape of Good Hope has been found
preferable, in these observations, to any other station in
the hemisphere.
The expedition which went to Peru, about the middle of
the last century, to ascertain, in conjunction with another
in Lapland, the true figure of the earth, found the
attraction of the mountainous regions so strong as to cause
the plum-line of one of their large instruments to deflect
seven or eight seconds from the true perpendicular; whilst
the elevated plains at the Cape unite all the advantages of
a lucid atmosphere with an entire freedom from mountainous
obstruction. Sir John Herschel, therefore, not only
accepted the appointment with high satisfaction, but
requested that it might commence at least a year before the
period of the transit, to afford him time to bring his
ponderous and complicated machinery into perfect adjustment,
and to extend his knowledge of the southern constellations.
His wish was immediately assented to, and his
arrangements being completed, he sailed from London on the
4th of September, 1934, in company with Dr. Andrew Grant,
Lieutenant Drummond, of the Royal Engineers, F.R.A.S., and a
large party of the best English mechanics. They arrived,
after an expeditious and agreeable passage, and immediately
proceeded to transport the lens, and the frame of the large
observatory, to its destined site, which was a piece of
table-land of great extent and elevation, about thirty-five
miles to the north-east of Capetown; and which is said to be
the very spot on which De la Caille, in 1750, constructed
his invaluable solar tables, when he measured a degree of
the meridian, and made a great advance to exactitude in
computing the solar parallax from that of Mars and the Moon.
Sir John accomplished the ascent to the plains by means of
two teams of oxen, of eighteen each, in about four days;
and, aided by several companies of Dutch boors, proceeded at
once the erection of his gigantic fabric.
The ground plan of the structure is in some respects
similar to that of the Herschel telescope in England, except
that instead of circular foundations of brickwork, it
consists of parallel circles of railroad iron, upon wooden
framework; so constructed that the turn-outs, or rather
turn-ins, from the largest circle, will conduct the
observatory, which moves upon them, to the innermost circle,
which is the basis of the lens-works; and to each of the
circles that intervene. The diameter of the smallest circle
is twenty-eight feet: that of the largest our correspondent
has singularly forgotten to state, though it may be in some
measure computed from the angle of incidence projected by
the lens, and the space occupied by the observatory. The
latter is a wooden building fifty feet square and as many
high, with a flat roof and gutters of thin copper. Through
the side proximate to the lens, is an aperture four feet in
diameter to receive its rays, and through the roof another
for the same purpose in meridional observations.
The lens, which is enclosed in a frame of wood, and
braced to its corners by bars of copper, is suspended upon
an axis between two pillars which are nearly as high as
those which supported the celebrated quadrant of Uleg Beg,
being one hundred fifty feet. These are united at the top
and bottom by cross-pieces, and strengthened by a number of
diagonal braces; and between them is a double capstan for
hoisting the lens from its horizontal line with the
observatory to the height required by its focal distance
when turned to the meridian; and for elevating it to any
intermediate degree of altitude that may be needed. This
last operation is beautifully regulated by an immense double
sextant, which is connected and moves with the axis of the
lens, and is regularly divided into degrees, minutes and
seconds; and the horizontal circles of the observatory being
also divided into 360 degrees, and minutely subdivided, the
whole instrument has the powers and regularity of the most
improved theodolite. Having no tube, it is connected with
the observatory by two horizontal levers, which pass
underneath the floor of that building from the circular
basis of the pillars; thus keeping the lense always square
with the observatory, an securing to both a uniform and
simple movement. By means of these levers, too, a rack and
windlass, the observatory is brought to any degree of
approximation to the pillars that the altitude of an
observation may require; and although, when at its nearest
station it cannot command an observation with the great lens
within about fifteen degrees of the meridian, it is supplied
with an excellent telescope of vast power, constructed by
the elder Herschel, by which every high degree can be
surveyed. The field of view, therefore, whether exhibited
on the floor or the wall of the apartment, has a diameter of
nearly fifty feet, and being circular, it has therefore an
area of 1875 feet.
The place of all the horizontal movements having been
accurately levelled by Lieut. Drummond, with the improved
level of his invention which bears his name, and the wheels
both of the observatory and of the lens-works being
facilitated by friction-rollers in patent axle-boxes filled
with oil, the strength of one man applied to the extremity
of the levers is sufficient to propel the whole structure
upon either of the railroad circles; and that of two men
applied to the windlass is fully adequate to bring the
observatory to the basis of the pillars. Both of these
movements, however, are now effected by a locomotive
apparatus commanded within the apartment by a single person,
and showing, by means of an ingenious index, every inch of
progression or retrogression.
We have not thus particularly described the telescope
of the younger Herschel because we consider it the most
magnificent specimen of philosophical mechanism of the
present or any previous age, but because we deemed an
explicit description of its principles and powers an almost
indispensable introduction to a statement of the sublime
expansion of human knowledge which is has achieved. It was
not fully completed until the latter part of December, when
the series of large reflectors for the microscope arrived
from England; and it was brought into operation during the
first week of the ensuing month and year. But the
secresy which had been maintained with regard to its
novelty, its manufacture, and its destination, was not less
rigidly preserved for several months respecting the grandeur
of its success. Whether the British Government were
sceptical concerning the promised splendor of its
discoveries, or wished them to be scrupulously veiled until
they had accumulated a full-orbed glory for the nation and
reign in which they originated, is a question which we can
only conjecturally solve. But certain it is that the
astronomer's royal patrons enjoined a masonic taciturnity
upon him and his friends until he should have officially
communicated the results of his great experiment.
Accordingly, the world heard nothing of him or his
expedition until it was announced a few months since in the
scientific journals of Germany, that Sir John Herschel, at
the Cape of Good Hope, had written to the astronomer-royal
of Vienna, to inform him that the portentous comet predicted
for the year 1835, which was to approach so near this
trembling globe that we might hear the roaring of its fires,
had turned upon another scent, and would not even shake a
hair of its tail upon our hunting-grounds. At a loss to
conceive by what extra authority he had made so bold a
declaration, the men of science of Europe who were not
acquainted with his secret, regarded his "postponement," as
his discovery was termed, with incredulous contumely, and
continued to terrorize upon the strength of former
predictions.
NEW LUNAR DISCOVERIES
Until the 10th of January,the observations were chiefly
directed to the stars in the southern signs,in which,
without the aid of the hydro-oxygen reflectors,a countless
number of new stars and nebulae were discovered. But we
shall defer our correspondent's account of these to future
pages for the purpose of no longer withholding from our
readers the more generally and highly interesting
discoveries which were made in the lunar world. And for
this purpose,too,we shall defer Dr.Grants elaborate
mathematical details of the corrections which Sir John
Herschel has made in the best tables of the moon's tropical,
sidercal, and synodic on which a great part of the
established lunar theory depends.
It was about half past nine o'clock on the night of the
tenth, the moon having then advanced within four days of her
mean liberation, that the astronomer adjusted his
instruments for the inspection of her eastern limb. The
whole immense power of his telescope was applied and to its
focal image about one half of the power of his microscope.
On removing the screen of the latter, the field of view was
covered throughout its entire area with a beautifully
distinct, and even vivid representation of basaltic rock.
Its color was a greenish brown, and the width of the
columns, as defined by their interstices on the canvass, was
invariably twenty-eight inches. No fracture whatever
appeared in the mass first presented, but in a few seconds a
shelving pile appeared of five or six columns width, which
showed their figure to be hexagonal, and their articulations
similar to those of the basaltic formation at Staffa. This
precipitous shelf was profusely covered with a dark red
flower, "precisely similar," says Dr. Grant, "to the Papaver
Rhoeas, or rose-poppy of our sublunary cornfields; and this
was the first organic production of nature, in a foreign
world, ever revealed to the eyes of men."
The rapidity of the moon's ascension, or rather of the
earth's diurnal rotation, being nearly equal to five hundred
yards in a second, would have effectually prevented the
inspection, or even the discovery of objects so minute as
these, but for the admirable mechanism which constantly
regulates, under the guidance of the sextant, the required
altitude of the lens. But its operation was found to be so
consummately perfect, that the observers could detain the
object upon the field of view for any period they might
desire. The specimen of lunar vegetation, however, which
they had already seen, had decided a question of too
exciting an interest to induce them to retard its exit. It
had demonstrated that the moon has an atmosphere constituted
similarly to our own, and capable of sustaining organized,
and therefore, most probably animal life. The basaltic
rocks continued to pass over the inclined canvass plane,
through three successive diameters, when a verdant declivity
of great beauty appeared, which occupied two more. This was
preceded by another mass of nearly the former height, at the
base of which they were at length delighted to perceive that
novelty, a lunar forest. "The trees," says Dr. Grant, "for
a period of ten minutes, were of one unvaried kind, and
unlike any I have seen, except the largest kind of yews in
the English churchyards, which they in some respects
resemble. These were followed by a level green plain,
which, as measured by the painted circle on our canvass of
forty-nine feet, must have been more than half a mile in
breadth; and then appeared as fine a forest of firs,
unequivocal firs, as I have ever seen cherished in the bosom
of my native mountains.
Wearied with the long continuance of these, we greatly
reduced the magnifying power of the microscope, without
eclipsing either of the reflectors, and immediately
perceived that we had been insensibly descending, as it
were, a mountainous district of a highly diversified and
romantic character, and that we were on the verge of a lake,
or inland sea; but of what relative locality or extent, we
were yet too greatly magnified to determine. On introducing
the feeblest acromatic lens we possessed, we found that the
water, whose boundary we had just discovered, answered in
general outline to the Mare Nubium of Riccoli, by which we
detected that, instead of commencing, as we supposed, on the
eastern longitude of the planet, some delay in the elevation
of the great lens had thrown us nearly upon the axis of her
equator.
However, as she was a free country, and we not, as yet,
attached to any particular province, and moreover, since we
could at any moment occupy our intended position, we again
slid our magic lenses to survey the shores of the Mare
Nubium. Why Riccoli so termed it, unless in ridicule of
Cleomedes, I know not; for fairer shores never angels
coasted on a tour of pleasure. A beach of brilliant white
sand, girt with wild castellated rocks, apparently of green
marble, varied at chasms, occurring every two or three
hundred feet, with grotesque blocks of chalk or gypsum, and
feathered and festooned at the summit with the clustering
foliage of unknown trees, moved along the bright wall of our
apartment until we were speechless with admiration. The
water, we obtained a view of it, was nearly as blue as that
of the deep ocean, and broke in large white billows upon the
strand. The action of very high tides was quite manifest
upon the face of the cliffs for more than a hundred miles;
yet diversified as the scenery was during this and a much
greater distance, we perceived no trace of animal existence,
notwithstanding we could command at will a perspective or a
foreground view of the whole. Mr. Holmes, indeed,
pronounced some white objects of a circular form, which we
saw at some distance in the interior of a cavern, to be bona
fide specimens of a large cornu ammonis; but to me they
appeared merely large pebbles, which had been chafed and
rolled there by the tides. Our chase of animal life was not
yet to be rewarded.
Having continued this close inspection of nearly two
hours, during which we passed over a wide tract of country,
chiefly of a rugged and apparent volcanic character; and
having seen few additional varieties of vegetation, except
some species of lichen, which grew everywhere in great
abundance, Dr. Herschel proposed that we should take out all
our lenses, give a rapid speed to the panorama, and search
for some of the principal valleys known to astronomers, as
the most likely method to reward our first night's
observation with the discovery of animated beings. The
lenses being removed, and the effulgence of our unutterably
glorious reflectors left undiminished, we found in
accordance with our calculations, that our field of view
comprehended about twenty-five miles of the lunar surface,
with the distinctness both of outline and detail which could
be procured of a terrestrial object at a distance of two and
a half miles; an optical phenomenon which you will find
demonstrated in Note 5. This afforded us the best landscape
views we had hitherto obtained, and although the accelerated
motion was rather too great, we enjoyed them with rapture.
Several of these famous valleys, which are bounded by
lofty hills of so perfectly conical a form as to render them
less like works of nature than or art, passed the canvass
before we had time to check their flight; but presently a
train of scenery met our eye, of features so entirely novel,
that Dr. Herschel signalled for the lowest convenient
gradation of movement. It was a lofty chain of
obelisk-shaped, or very slender pyramids, standing in
irregular groups, each composed of about thirty or forty
spires, every one of which was perfectly square, and as
accurately truncated as the finest specimens of Cornish
crystal. They were of a faint lilac hue, and very
resplendent. I now thought that we had assuredly fallen on
productions of art; but Dr. Herschel shrewdly remarked, that
if the Lunarians could build thirty or forty miles of such
monuments as these, we should ere now have discovered others
of a less equivocal character. He pronounced them quartz
formations, of probably wine-colored amethyst species, and
promised us, from these and other proofs which he had
obtained of the powerful action of laws of crystallization
in this planet, a rich field of mineralogical study.
On introducing a lens, his conjecture was fully
confirmed; they were monstrous amethysts, of a diluted
claret color, glowing in the intensest light of the sun!
They varied in height from sixty to ninety feet, though we
saw several of a still more incredible altitude. They were
observed in a succession of valleys divided by longitudinal
lines of round-breasted hills, covered with verdure and
nobly undulated; but what is most remarkable, the valleys
which contained these stupendous crystals were invariably
barren, and covered with stones of a ferruginous hue, which
were probably iron pyrites. We found that some of these
curiosities were situated in a district elevated half a mile
above the valley of the Mare Foecunditatis, of Mayer and
Riccoli; the shores of which soon hove into view. But never
was a name more appropriately bestowed, From "Dan to
Bersheba" all was barren, barren - the sea-board was
entirely composed of chalk and flint, and not a vestige of
vegetation could be discovered with our strongest glasses.
The whole breadth of the northern extremity of the
sea, which was about three hundred miles, having crossed our
plane, we entered upon a wild mountainous region abounding
with more extensive forests of larger trees than we had seen
before -- the species of which I have no good analogy to
describe. In general contour they resembled our forest oak;
but they were much more superb in foliage, having broad
glossy leaves like that of the laurel, and tresses of yellow
flowers which hung, in the open glades, from the branches to
the ground. These mountains passed, we arrived at a region
which filled us with utter astonishment. It was an oval
valley, surrounded, except at narrow opening towards the
south, by hills, red as the purest vermilion, and evidently
crystallized; for wherever a precipitous chasm appeared --
and these chasms were very frequent, and of immense depth --
the perpendicular sections present conglomerated masses of
polygon crystals, evenly fitted to each other, and arranged
in deep strata, which grew darker in color as they descended
to the foundations of the precipices. Innumerable cascades
were bursting forth from the breasts of every one of these
cliffs, and some so near their summits, and with such great
force, as to form arches many yards in diameter. I never
was so vividly reminded of Byron's simile, "the tale of the
white horse in the Revolution." At the foot of this
boundary of hills was a perfect zone of woods surrounding
the whole valley, which was about eighteen or twenty miles
wide, at its greatest breadth, and about thirty in length.
Small collections of trees, of every imaginable kind, were
scattered about the whole of the luxuriant area; and here
our magnifiers blest our panting hopes with specimens of
conscious existence.
In the shade of the woods on the south-eastern side,
we beheld continuous herds of brown quadrupeds, having all
the external characteristics of the bison, but more
diminutive than any species of the bos genus in our natural
history. Its tail is like that of our bos grunniens; but in
its semi-circular horns, the hump on its shoulders, and the
depth of its dewlap, and the length of its shaggy hair, it
closely resembled the species to which I first compared it.
It had, however, one widely distinctive feature, which we
afterwards found common to nearly every lunar quadruped we
have discovered; namely, a remarkable fleshy appendage over
the eyes, crossing the whole breadth of the forehead and
united to the ears. We could most distinctly perceive this
hairy veil, which was shaped like the upper front outline of
a cap known to the ladies as Mary Queen of Scots' cap,
lifted and lowered by means of the ears. It immediately
occurred to the acute mind of Dr. Herschel, that this was a
providential contrivance to protect the eyes of the animal
from the extremes of light and darkness to which all the
inhabitants of our side of the moon are periodically
subjected.
The next animal perceived would be classed on earth as
a monster. It was of a bluish lead color, about the size of
a goat, with a head and beard like him, and a single horn,
slightly inclined forward from the perpendicular. The
female was destitute of horn and beard, but had a much
longer tail. It was gregarious, and chiefly abounded on the
acclivitous glades of the woods. In elegance of symmetry it
rivalled the antelope, and like him it seemed an agile
sprightly creature, running with great speed, and springing
from the green turf with all the unaccountable antics of a
young lamb or kitten. This beautiful creature afforded us
the most exquisite amusement. The mimicry of its movements
upon our white painted canvass was as faithful and luminous
as that of animals within a few yards of the camera obscrua,
when seen pictures upon its tympan. Frequently when
attempting to put our fingers upon its beard, it would
suddenly bound away into oblivion, as if conscious of our
earthly impertinence; but then others would appear, whom we
could not prevent from nibbling the herbage, say or do what
we would to them.
On examining the centre of this delightful valley, we
found a large branching river, abounding with lovely
islands, and water-birds of numerous kinds. A species of
grey pelican was the most numerous; but a black and white
crane, with unreasonably long legs and bill, were also quite
common. We watched their pisciverous experiments a long
time, in hopes of catching sight of a lunar fish; but
although we were not gratified in this respect, we could
easily guess the purpose with which they plunged their long
necks so deeply beneath the water. Near the upper extremity
of one of these islands we obtained a glimpse of a strange
amphibious creature, of a spherical form, which rolled with
great velocity across the pebbly beach, and was lost sight
of in the strong current which set off from this angle of
the island. We were compelled, however, to leave this
prolific valley unexplored, on account of clouds which were
evidently accumulating in the lunar atmosphere, our own
being perfectly translucent. But this was itself an
interesting discovery, for more distant observers had
questioned or denied the existence of any humid atmosphere
in this planet.
The moon being now low on her descent, Dr. Herschel
inferred that the increasing refrangibility of her rays
would prevent any satisfactory protraction of our labors,
and our minds being actually fatigued with the excitement of
the high enjoyments we had partaken, we mutually agreed to
call in the assistants at the lens, and reward their
vigilant attention with congratulatory bumpers of the best
"East Indian Particular." It was not, however, without
regret that we left the splendid valley of the red
mountains, which, in compliment to the arms of our royal
patron, we denominated "the Valley of the Unicorn;" and it
may be found in Blunt's map, about midway between the Mare
Faecunditatis and the Mare Nectaris.
The nights of the 11th and 12th being cloudy, were
unfavorable to observation; but on those of the 13th and
14th further animal discoveries were made of the most
exciting interest to every human being. We give them in the
graphic language of our accomplished correspondent:-
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