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There had been rain
during the night; and when I first got on deck, a little after seven, a
low stratum of mist, that completely enveloped the Scuir, and truncated
both the eminence on which it stands and the opposite height, stretched
like a ruler across the flat valley which indents so deeply the middle of
the island. But the fogs melted away as the morning rose, and ere our
breakfast was satisfactorily discussed, the last thin wreath had
dispappeared from around the columned front of the rock-tower of Eigg, and
a powerful sun looked down on moist slopes and dank hollows, from which
there arose in the calm a hazy vapour, that, while it softened the lower
features of the landscape, left the bold outline relieved against a clear
sky. Accompanied by our attendant of the previous day, bearing bag and
hammer, we set out a little before eleven for the north-western side of
the island, by a road which winds along the central hollow. My friend
showed me as we went, that on the edge of an eminence, on which the
traveller journeying westwards catches the last glimpse of the chapel of
St. Donan, there had once been a rude cross erected, and another rude
cross on an eminence on which he catches the last glimpse of the first;
and that there had thus been a chain of stations formed from sea to sea,
like the sights of a land-surveyor, from one of which a second could be
seen, and a third from the second, till, last of all, the emphatically
holy point of the island, - the burial-place fo the old Culdee, - came
full in view. The unsteady devotion, that journeyed, fancy-bound,along the
heights , to gloat over a dead man’s bones, had its clue to carry it on in
a straight line. Its trail was on the ground; it glided snake-like from
cross to cross, in quest of dust; and without its finger-posts to guide
it, would have wandered devious , It is surely a better devotion that,
instead of thus creeping over the earth to a mouldy sepulchre, can at once
launch into the sky, secure of finding Him who arose from one. In less
than an hour we were descending on the Bay of Laig, a semicircular
indentation of thecoast about a mile in length, and, where it opens to the
main sea, nearly two miles in breadth; with the noble island of Rum rising
high in front, like some vast breakwater; amd a meniscus of comparatively
level land, walled in behind by a semicircular rampart of continuous
precipice, sweeping round its shores.There are few finer scenes in the
Hebrides than that furnished by this island bay and its picturesque
accompaniments, - none that break more unexpectedly on the traveller who
descends upon it from the east; and rarely has it been seen to greater
advantage than on the delicate day, so soft, and yet so sunshiny and
clear, on which I paid it my first visit.
The island of Rum, with its
abrupt sea-wall of rock, and its steep-pointed hills, that attain,
immediately over the sea, an elevation of more than two thousand feet,
loomed bold and high in the offing, some five miles away, but apparently
much nearer. The four tall summits of the island rose clear against the
sky, like a group of pyramids; its lower slopes and precipices, variegated
and relieved by graceul alternations of light and shadow, and resting on
their blue basement of sea, stood out with equal distinctnes; but the
entire middle space from end to end was hidden in a long horizontal
stratum of gray cloud, edged atop with a lacing of silver. Such was the
aspect of the noble breakwater in front. Fully two-thirds of the
semi-circular rampart of rock which shuts in the crescent-shaped plain
directly opposite lay in deep shadow; but the sun shone softly on the
plain itself, brightening up many a dingy cottage, and many a green patch
of corn; and the bay below stretched out, sparkling in the light. There is
no part of the island so thickly inhabited as this flat meniscus. It is
composed almost entirely of Oolitic rocks, and bears atop, especially
where an ancient oyster-bed of great depth forms the subsoil, a kindly and
fertile mould. The cottages lie in groupes; and, save where a few bogs,
which it would be no very difficult matter to drain, interpose their rough
shag of dark green,` and break the continuity, the plain around them waves
with corn. Lying fair, green nd populous within the sweep of its
inaccessible rampart of rock, at least twice as lofty as the ramparts of
Babylon of old, it reminds one of the suburbs of some ancient city lying
embosomed, with all its dwellings and fields, within some roomy crescent
of the city wall. We passed, ere we entered on the level, a steep-sided
narrow dell, through which a small stream finds its way from the higher
grounds, and which terminates at the upper end in an abrupt precipice, and
a lofty but very slim cascade. “One of the few superstitions that still
linger on the island,” said my friend the minister, “ is associated with
that wild hollow. It is believed that shortly before a death takes place
among the inhabitants, a tall withered female may be seen in the twilight,
just yonder where the rocks open, washing a shroud in the stream. John,
there, will perhaps tell you how she was spoken to on one occasion, by an
over-bold, over-inquisitive islander, curious to know whose shroud she was
preparing; and how she more than satisfied his curiosity, by telling him
it was his own. It is a not uninteresting fact,” added the minister, “that
my poor people, since they have become more earnest about their religion,
think very little about ghosts and spectres: their faith in the realities
of the unseen world seems to have banished from their minds much of their
old belief in its phantoms.”
In the rude fences that
separate from each other the little farms in this plain, we find frequent
fragments of the oyster-bed, hardened into a tolerably compact limestone.
It is seen to most advantage, however, in some of the deeper cuttings in
the fields, where the surrounding matrix exists merely as an incoherent
shale; and the shells may be picked out as entire as when they lay, ages
before,in the mud, which we still see retaining around them its original
colour. They are small, thin, triangular, much resembling in form some
specimens of the Ostrea deltoidea, but greatly less in size. The nearest
resembling shell in Sowerby is the Ostrea acuminata, - an oyster of the
clay that underlies the great Oolite of Bath. Few of the shells exceed an
inch and half in length, and the majority fall short of an inch What they
lack in bulk, however, they make up in number. They are massed as thickly
together, to the depth of several feet, as shells on the heap at the door
of a Newhaven fisherman, and extend over many acres. Where they lie open
we can still detect the triangular disc of the hinge, with the single
impression of the adductor muscle; and the foliaceous character of the
shell remains in most instances as distinct as if it had undergone no
mineral change. I have seen nowhere in Scotland, among the secondary
formations, so unequivocal an oyster-bed; nor do such beds seem to be at
all common in formations older than the Tertiary in England, though the
oyster itself is sufficiently so. We find Mantell stating, in his recent
work (“Medals of Creation”), after first describing an immense oyster-bed
of the London Basin, that underlies the city (for what is now London was
once an oyster-bed), that in the chalk below, though it contains several
species of Ostrea, the shells are diffused promiscuously throughout the
general mass. Leaving, however, these oysters of the Oolite, which never
net inclosed not drag disturbed, though they must have formed the food of
many an extinct order of fish, - mayhap reptile, - we pass on in a
south-western direction, descending in the geological scale as we go, untl
we reach the southern side of the Bay of Laig. And there, far below
tidemark, we find a dark-coloured argillaceous shale of the Lias, greatly
obscured by boulders of trap, - the only deposit of the Liasic formation
in the island.]
A line of trap-hills that
rises along the shore seems as if it had strewed half its materials over
the beach. The rugged blocks lie thick as stones in a causeway, down to
the line of low ebb, - memorials of a time when the surf dashed against
the shattered bases of the trap-hills, now elevataed considerably beyond
it reach; and we can catch but partial glimpses of the shale below.
Wherever access to it can be had, we find it richly fossiliferous; but its
organisms, with the exception of its Belemnites, are very imperfectly
preserved. I dug up from under the trap-blocks some of the common Liasic
Amnmonites of the north-eastern coast of Scotland, a few of the septa of a
large Nautilus, broken pieces of wood, and half-effaced casts of what
seems a branched coral; but only minute portions of the shells have been
converted into stone; here and there a few chambers in the whorls of an
Ammonite or Nautilus, though the outline of the entire organism lies
impressed in the shale; and the ligneous and polyparious fossils we find
in a still greater state of decay. The Belemnite alone, as is common with
this robust fossil, so often the sole survivor of its many contemporaries,
- has preserved its structure entire. I disinterred from the shale good
specimens of the Belemnite sulcatus and Belemnite elongatus,and found,
detached on the surface of the bed, a fragment of a singularly large
Belemnite a full inch and a quarter in diameter, the species of which I
could not determine.
Returning by the track we
came, we reach the bottom of the bay, which we find much obscured with
sand and shingle; and pass northwards along its side, under a range of low
sandstone precipices, with interposing grassy slopes, in which the fertile
Ooliltic meniscus descends to the beach. The sandstone, white and soft,
and occurring in thick beds, much resembles that of the Oolite of
Sutherland. We detect in it few traces of fossils; now and then a
carbonaceous marking, and now and then what seems a thin vein of coal, but
which proves to be merely the bark of some woody stem, converted into a
glossy bituminous lignite, like that of Brora.But in beds of a blue clay,
intercalated with the sandstone, we find fossils in abundance, of a
character less obscure. We spent a full half-hour in picking out shells
from the bottom of a long dock-like hollow among the rocks, in which a bed
of clay has yielded to the waves, while the strata on either side stand up
over it like low wharfs on the opposite sides of a river. The shells,
though exceedingly fragile, - for they partake of the nature of the clayey
matrix in which they are embedded, - rise as entire as when they had died
among the mud, years, mayhap ages, ere the sandstone had been deposited
over them; and we were enabled at once to detect their extreme
dissimilarity, as a group, to the shells of the Liasic depoist we had so
lately quitted. We did not find in this bed a single Ammonite,Belemnite,
or Nautilus; but chalky Bivalves, resembling out existing Tellina, in vast
abundance, mixed with what seem to be a small Buccinum and a minute
Trochus, with numerous rather equivocal fragments of a shell resembling an
Oiliva. So thickly do they lie clustered together in this deposit, that in
some patches where the sad-coloured argillaceous ground is washed bare by
the sea; it seems marbled with them into a light gray tint. The group more
nearly resembles in type a recent one than any I have yet seen in a
secondary deposit, except perhaps in Weald of Moray, where we find in one
of the layers a Planorbis scarce distinguishable from those of our ponds
and ditches, mingled with a Paludina that seems as nearly modelled after
the existing form. From the absence of the more characteristic shells of
the Oolite, I am inclined to deem the deposit one of estuary origin. Its
clays were probably thrown down, like the silts of so many of our rivers,
in some shallow bay, where the waters of a descending stream mingled with
those of the sea, and where, though shells nearly akin to our existing
periwinkles and whelks congregated or the Nautilus orAmmonite hoisted its
membranaceous sail.
We pass on towards the
north. A thick bed of an extremely soft white sandstone presents here, for
nearly half a mile together, its front to the waves, and exhibits, under
the incessant wear of the surf, many singularly grotesque combinations of
form. The low precipices, undermined at the base, beetle over like the
sides of stranded vessels. One of the projecting promontories we find
hollowed through and through by a tall rugged archway; while the outer
pier of the arch, - if pier we may term it, - worn to a skeleton, and
jutting outwards with a knee-like angle, presents the appearance of a thin
ungainly leg and splay foot, advanced, as if in awkward courtesy, to the
breakers. But in a winter or two, judging from its present degree of
attenuation, and the yielding nature of its material, which resembles a
damaged mass of arrowroot consolidated by lying in the leaky hold of a
vessel, its persevering courtesies will be over, and pier and archway must
lie in shapeless fragments on the beach. Wherever the surf has broken into
the upper surface of this sandstone bed, and worn it down to nearly the
level of the shore, what seem a number of double ramparts, fronting each
other, and separated by deep square ditches exactly parallel in the sides,
traverse the irregular level in every direction. The ditches vary in width
from one to twelve feet; and the ramparts, rising from three to six feet
over them, are perpendicular as the walls of houses, where they front each
other, and descend on the opposite sides in irregularslopes. The iron
block, with square groove and projecting ears, that receives the bar of a
railway, and connects it with the stone below, represents not inadequately
a section of one of these ditches with its ramparts. They form here the
sole remains of dykes of an earthy trap, which, though at one time in a
state of such high fusion that they converted the portions of soft
sandstone in immediate contact with them into the consistence of quartz
rock, have long since mouldered away, leaving but the hollow rectilinear
rents which they had occupied, surmounted by the indurated walls which
they had baked.Some of the most curious appearances, however, connected
with the sandstone, though they occur chiefly in an upper bed, are
exhibited by what seem fields of petrified mushrooms, of a gigantic size,
that spread out in some places for hundreds of yards under the high-water
level. These apparent mushrooms stand on thick squat stems, from a foot to
eighteen inches in height: the heads are round, like those of toad-stools,
and vary from one foot to nearly two yards in diameter. In some specimens
we find two heads joined together in a form resembling a squat figure of
eight, of what printers term the Egyptian type, or, to borrow the
illustration of M’Culloch, “like the ancient military projectile known by
the name of double-headed shot;” in other specimens three heads have
coalesced in a trefoil shape, or rather in a shape like that of an ace of
clubs divested of the stem. By much the greater number, however, are
spherical. They are composed of concretionary masses, consolidated, like
the walls of the dykes, though under some different process, into a hard
siliceous stone, that has resisted those disintegrating influences of the
weather and the surf under which the yielding matrix in which they were
embedded has worn from around them. Here and there we find them lying
detached on the beach, like huge shot, compared with which the greenstone
balls of Mons Meg are but marbles for children to play with; in other
cases they project from the mural front of rampart-like precipices, as if
they had been showered into them by the ordnance of some besieging
battery, and had stuck fast in the mason-work. Abbotsford has been
described as a romance in stone and lime: we have here, on the shores of
Laig, what seems a wild but agreeable tale, of the extravagant cast of
“Christabel,” or the “Rhyme of the Ancient Mariner,” fretted into
sandstone. But by far the most curious part of the story remains to be
told.
The hollows and fissures of
the lower sandstone bed we find filled with a fine quartzose sand, which,
from its pure white colour, and the clearness with which the minute
particles reflect the light, reminds one of accumulations of potato-flour
drying in the sun. It is formed almost entirely of disintegrated particles
of the soft sandstone; and as we at first find it occurring in mere
handfuls, that seem as if they had been detached from the mass during the
last few tides, we begin to marvel to what quarter the missing materials
of the many hundred cubic yards of rock, ground down along the shore in
this bed during the last century or two, have been conveyed away. As we
pass on northwards, however, we see the white sand occurring in much
larger quantities, - here heaped up in little bent-covered hillocks above
the reach of the tide, - there stretching out in level, ripple-marked
wastes into the waves, - yonder rising in flat narrow spits among the
shallows. At length we reach a small, irregularly-formed bay, a few
hundred feet across, floored with it from side to side; and see it, on the
one hand, descending deep into the sea, that exhibits over its whiteness a
lighter tint of green, and, on the other, encroaching on the land, in the
form of drifted banks, covered with the plants common to our tracts of
sandy downs. The sandstone bed that has been worn down to form it contains
no fossils, save here and there a carbonaceous stem; but in an underlying
harder stratum we occasionally find a few shells; and, with a specimen in
my hand charged with a group of bivalves resembling the existing
conchifera of our sandy beaches, I was turning aside this sand of the
Oolite, so curiously reduced to its original state, and marking how nearly
the recent shells that lay embedded in it resembled the extinct ones that
had lain in it so long before, when I became aware of a peculiar sound
that it yielded to the tread, as my companions paced over it. I struck it
obliquely with my foot, where the surface lay dry and incoherent in the
sun, and the sound elicited was a shrill sonorous note, somewat resembling
that produced by a waxed thread, when tightened between the teeth and the
hand, and tipped by the nail of the forefinger. I walked over it, striking
it obliquely at each step, and with every blow the shrill note was
repeated. My companions joined me; and we performed a concert, in which,
if we could boast of but little variety in the tones produced, we might at
least challenge all Europe for an instrument of the kind which produced
them. It seemed less wonderful that there should be music in the granite
of Memnon, than in the loose Oolitic sand of the Bay of Laig. As we
marched over the drier tracts, an incessant woo, woo, woo, rose from the
surface, that might be heard in the calm some twenty or thiry yards away;
and we found that where a damp semi-coherent stratum lay at the depth of
three or four inches beneath, and all was dry and incoherent above, the
tones were loudest and sharpest, and most easily evoked by the foot. Our
discovery, - for I trust I may regard it as such, - adds a third locality
to two previously known ones , in which what may be termed the musical
sand, - no unmeet counterpart to the “singing water” of the tale, - has
now been found. And as the island of Eigg is considerably more accessible
than Jabel Nakous in Arabia Petraea, of .Reg-Rawan in the neighbourhood of
Cabul, there must be facilities presentedthrough the discovery which did
not exist hitherto, for examing the phenomenon in acoustics which it
exhibits, - a phenomenon, it may be added, which some of out greatest
masters of the science have confessed their inability to explain.
Jabel Nakous, or the
“Mountain of the Bell,” is situated about three miles from the shores of
the Gulf of Suez, in that land of wonders which witnessed for forty years
the journeyings of the Israelites, and in which the granite peaks of Sinai
and Horeb overlook an arid wilderness of rock and sand. It had been known
for many ages by the wild Arab of the desert, that there rose at times
from this hill a strange, inexplicable music. As he leads his camel past
in the heat of the day, a sound like the first low tones of an Aeolian
harp stirs the hot breezeless air. It swells louder and louder in
progressive undulations, till at length the dry baked earth seems to
vibrate under foot, and the startled animal snorts and rears, and
struggles to break away. According to the Arabian account of the
phenomenon, says Sir David Brewster, in his “Letters on Natural Magic,”
there is a convent miraculously preserved in the bowels of the hill; and
the sounds are said to be those of the “Nakous, a long metallic ruler,
suspended horizontally, which the priest strikes with a hammer, for the
purpose of assembling the monks to prayer.” There exists a tradition that
on one occasion a wandering Greek saw the mountain open, and that,
entering by the gap, he descended into the subterranean convent, where he
found beautiful gardens and fountains of delicious water, and brought with
him to the upper world, on his return, fragments of consecrated bread. The
first European traveller who visited Jabel Nakous, says Sir David, was M.
Seetzen, a German. He journeyed for several hours over arid sands, and
under ranges of precipices inscribed by mysterious characters, that tell,
haply, of the wanderings of Israel under Moses. And reaching, about noon,
the base of the musical fountain, he found it composed of a white friable
sandstone, and presenting on two of its sides sandy declivities. He
watched beside it for an hour and a quarter, and then heard, for the first
time, a low undulating sound, somewhat resembling that of a humming top,
which rose and fell, and ceased and began, and then ceased again; and in
an hour and three quarters after, when in the act of climbing along the
declivity, he heard the sound yet louder and more prolonged.It seemed as
if issuing from under his knees, beneath which the sand, disturbed by his
efforts,was sliding downwards along the surface of the rock.Concluding
that the sliding sand was the cause of the sounds, not an effect of the
vibrations which they occasioned, he climbed to the top of one of the
declivities, and, sliding downwards, exerted himself with hands and feet
to set the sand in motion. The effect produced far exceeded his
expectations: the incoherent sand rolled under and around in a vast sheet;
and so loud was the noise produced, that “the earth seemed to tremble
beneath him to such a degree, that he states he should certainly have been
afraid if he had been ignorant of the cause.” At the time Sir David
Brewster wrote (1832), the only other European who had visited Jabel
Nakous was Mr. Grey, of University College, Oxford. This gentleman
describes the noises he heard, but which he was unable to trace to their
producing cause, as “beginning with a low continuous murmuring sound,
which seemed to rise beneath his feet,” but “which gradually changed into
pulsations as it became louder, so as to resemble the striking of a clock,
and became so strong at the end of five minutes as to detach the sand.’The
Mountain of the Bell has been since carefully explored by Lieutenant J.
Welsted of the Indian Navy; and the reader may see it exhibited in a fine
lithograph, in his travels, as a vast irregularly-conical mass of broken
stone, somewhat resembling one of our Highland cairns, though, of course,
on a scale immensely more huge, with a steep angualar slope of sand
resting in a hollow in one of its sides, and rising to nearly its apex.
“It forms,” says Lieutenant Welsted, “one of a ridge of low calcareous
hills, at a distance of three and a half miles from the beach, to which a
sandy plain, extending with a gentle rise to their base, connects them.
Its height, about four hundred feet, as well as the material of which it
is composed,-a light -coloured friable sandstone,-is about the same as the
rest of the chain; but an inclined plane of almost impalpable sand rises
at an angle of forty degrees with the horizon, and is bounded by a
semicircle of rocks, presenting broken, abrupt,and pinnacled forms, and
extending to the base of this remarkable hill. Although their shape and
arrangement in some respects may be said to resemble a whispering gallery,
yet I determined by experiment that their irregular surface renders them
but ill adapted for the production of an echo. Seated at a rock at the
base of the sloping eminence, I directed one of the Bedouins to ascend;
and it was not until he had reached some distance that I perceived the
sand in motion, rolling down the hill to the depth of a foot. It did not,
however, descend in one continued stream; but, as theArab scrambled up, it
spread out laterally and upwards,until a considerable portion of the
surface was in motion. At their commencement the sounds might be compared
to the faint strains of an AEolian harp when its strings first catch the
breeze: as the sand became more violently agitated by the increased
velocity of the descent, the noise more nearly resembled that produced by
drawing the moistened fingers over glass. As it reached the base, the
reverberations attained the loudness of distant thunder, causing the rock
on which we were seated to vibrate; and our camels, - animals not easily
frightened, - became so alarmed, that it was with difficulty their drivers
could restrain them.”
The hill of Reg-Rawan, or
the ‘Moving Sand,” says the late Sir Alexander Burnes, by whom the place
was visited in the autumn of 1837, and who has recorded his visit in a
brief paper, illustrated by a rude lithographic view, in the “Journal of
the Asiatic Society” for 1838, “is about forty miles north of Cabul,
towards Hindu-kush, and near the base of the mountains.” It rises to the
height of about four hundred feet, in an angle formed by the junction of
two ridges of hills; and a sheet of sand, “pure as that of the sea-shore,”
and which slopes in an angle of forty degrees, reclines against it from
base to summit. As represented in the lithograph, there projects over the
steep sandy slope on each side, as in “the Mountain of the Bell,” still
steeper barriers of rock; and we are told by Sir Alexander, that though
“the mountains here are generally composed of granite or mica, at
Reg-Rawan there is sandstone and lime.” The situation of the sand is
curious, he adds: it is seen from a great distance; and as there is none
other in the neighbourhood, “it might almost be imagined, from its
appearance, that the hill had been cut in two, and that the sand had
gushed forth as from a sand-bag.” “When set in motion by a body of people
who slide down it, a sound is emitted. On the first trial we distinctly
heard two loud hollow sounds, such as would be given by a large drum;” -
“there is an echo in the place; and the inhabitants have a belief that the
sounds are only heard on Friday, when the saint of Reg-Rawan, who is
interred hard by, permits.” The phenomenon, like the resembling one in
Arabia, seems to have aattracted attention among the inhabitants of the
country at an early period; and the notice of an eastern annalist, the
Emperor Baber, who flourished late in the fifteenth century, and, like
Caesar, conquered and recorded his conquests, still survives. He describe
it as the Khwaja Reg-Rawan, “a small hill, in which there is a line of
sandy ground reaching from the top to the bottom,” from which there
“issues in the summer season the sound of drums and nagarets,” In
connection with the fact that the musical sand of Eigg is composed of a
disintegrated sandstone of the Oolite, it is not quite unworthy of notice
that sandstone and lime enter into the composition of the hill of
Reg-Rawan, - that the district in which the hill is situated is not a
sandy one, - and that its slope of sonorous sand seems as if it had issued
from its side.These various circumstances, taken together, lead to the
inference that the sand may have originated in the decompostion of the
rock beneath. It is further noticeable, that the Jabel Nakous is composed
of a white friable sandstone, resembling that of the the white friable bed
of the Bay of Laig, and that it belongs to nearly the same geological
era.I owe to the kindness of Dr. Wilson of Bombay, two specimens which he
picked up in Arabia Petraea, of spines of Cidarites of the mace-formed
type so common in the Chalk and Oolite, but so rare in the older
formations. Dr. Wilson informs me that they are of frequent occurrence in
the desert of Arabia Petraea, where they are termed by the Arabs petrified
olives; that nummulites are also abundant in the district; and that the
various secondary rocks he examined in his route through it seem to belong
to the Cretaceous group. It appears not improbable, therefore, that all
the sonorous sand in the world yet discovered is formed, like that of
Eigg, of disintegrated sandstone; and at least two-thirds of it of the
disintegrated sandstone of secondary formations, newer than the Lias. But
how it should be at all sonorous, whatever its age or origin, seems yet to
be discovered. There are few substances that appear worse suited than sand
to communicate to the atmosphere those vibratory undulations that are the
producing causes of sound: the grains, even when sonorous individually,
seem, from their inevitable contact with each other, to exist under the
influence of that simple law in acoustics which arrests the tones of the
ringing glass or struck bell, immediately as they are but touched by some
foreign body, such as the hand or finger. The one grain, ever in contact
with several other grains, is a glass or bell on which the hand always
rests. And the difficulty has been felt and acknowledged. Sir John
Herschel, in referring to the phenomenon of the Jabel Nakous, in his
“Treatise on Sound,” in the “Encyclopaedia Metropolitana,” describes it as
to him “utterly inexplicable;” and Sir David Brewster, whom I had the
pleasure of meeting in December last, assured me it was not less a puzzle
to him than to Sir John. An eastern traveller, who attributes its
production to “a reduplication of impulse setting air in vibration in a
focus of echo,” means, I suppose, saying nearly the same thing as the two
philosophers, and merely conveys his meaning in a less simple style.
I have not yet procured
what I expect to procure soon, - sand enough from the musical bay at Laig
to enable me to make its sonorous qualities the subject of experiment at
home. It seems doubtful whether a small quantity set in motion on an
artificial slope will serve to evolve the phenomena which have rendered
the Mountain of the Bell so famous. Lieutenant Welsted informs us, that
when his Bedouin first set the sand in motion, there was scarce any
perceptible sound heard; - it was rolling downwards for many yards around
him to the depth of a foot, ere the music arose; and it is questionable
whether the effect could be elicited with some fifty or sixty pounds
weight of the sand of Eigg, on a slope of but at most a few feet, which it
took many hundredweight of the sand of Jabel Nakous, and a slope of many
yards, to produce. But in the stillness of a close room, it is just
possible that it may. I have, however, little doubt, that from small
quantities the sounds evoked by the foot on the shore may be reproduced:
enough will lie within the reach of experiment to demonstrate the strange
difference which exists between this sonorous sand of the Oolite, and the
common unsonorous sand of our sea-beaches; and it is certainly worth while
examinng into the nature and producing causes of a phenomenon so curious
in itself, and which has been characterized by one of the most
distinguished of living philosophers as “the most celebrated of all the
acoustic wonders which the natural world presents to us.” In the
forthcoming number of the “North British Review,” - which appears on
Monday first,* - the reader will find the sonorous sand of Eigg referred
to, in an article the authorship of which will scarce be mistaken “We have
here,” says the writer, after first describing the sounds of Jabel Nakous,
and then referring to those of Eigg,”the phenomenon in its simple state,
disembarrassed from reflecting rocks, from a hard bed beneath, and from
cracks and cavities that might be supposed to admit the sand; and
indicating as its cause, either the accumulated vibrations of the air when
struck by the driven sand, or the accumulated sounds occasioned by the
mutual impact of the particles of sand against each other. If a
musket-ball passing through the air emits a whistling note, each
individual particle of sand must do the same, however faint be the note
which it yields; and the accumulation of these infinitesimal vibrations
must constitute an audible sound, varying with the number and velocity of
the moving particles. In like manner,if two plates of silex or quartz,
which are but large crystals of sand, give out a musical sound when
mutually struck, the impact or collision of two minute crystals or
particles of sand must do the same, in however inferior a degree; and the
union of all these sounds, though singly imperceptible, may constitute the
musical notes of the Bell Mountain, or the lesser sounds of the trodden
sea-beach at Eigg.”
Here is a vigorous effort
made to unlock the difficulty. I should, however, have mentioned to the
philosophic writer, - what I inadvertently failed to do, - that the sounds
elicited from the sand of Eigg seem as directly evoked by the slant blow
dealt it by the foot, as the sounds similarly evoked from a highly waxed
floor, or a board strewed over with ground rosin..The sharp shrill note
follows the stroke, altogher independently of the grains driven into the
air. My omission may serve to show how much safer it is for those minds of
the observant order, that serve as hands and eyes to the reflective ones,
to prefer incurring the risk of being even tediously minute in their
descriptions, to the danger of being inadequately brief in them,. But,
alas! for purposes of exact science, rarely are verbal descriptons other
that inadequate. Let us just look, for example, at the various accounts
given us of Jabel Nakous. There are strange sounds heard proceeding from a
hill in Arabia, and various travellers set themselves to describe them.
The tones are those of the convent Nakous, says the wild Arab; - there
must be a convent buried under the hill. More like the sounds of a humming
top, remarks a phlegmatic German traveller. Not quite like them, says an
English one in an Oxford gown; they resemble rather the striking of a
clock,. Nay, listen just a little longer and more carefully, says a second
Englishman, with epaulettes on his shoulder: “the sounds at their
commencement may compared to the faint strains of an AEolian harp when its
strings first catch the breeze,” but anon, as the agitation of the sand
increases, they “more nearly resemble those produced by drawing the
moistened fingers over glass.” Not at all, exclaims the warlike Zahor
Ed-Din Muhammad Baber, twirling his whiskers: “I know a similar hill in
the country towards Hindu-kush: it is the sound of drums and nagarets that
issues from the sand.” All we really know of this often-described music of
the desert, after reading all the descriptions, is, that its tones bear
certain analogies to certain other tones, - analogies that seem stronger
in one direction to one ear, and stronger in another direction to an ear
differently constituted, but which do not exactly resemble any othe sounds
in nature. The strange music of Jabel Nakous, as a combination of tones,
is essentially unique.
* March 31, 1845 |
