The Marietta journal. [volume] (Marietta, Ga.) 1866-1909, 1890-08-14
A SAND THAT BARKS.
AN ACCOUNT OF THE MUSICAL EARTH
OF THE SANDWICH ISLANDS.

Found in Several Countries-Some Nv
potheses to Explain the Cause.
The so-called barking sands of Kanai
are mentioned in the works of several
travellers in the Hawaiian islands. and
nave worldwide fame as natural curi-
os1ty. AS arule, however, the printed &C.
counts are meager in details, and show
Ine authors to have been unacquainted
with similar phenomena elsewhere.
Jointly with DR.. Alexis A. Julien, of
Colum bia college, New York, have been
studying the properties of sonorous sand
Tor long time, and have visited many
localities in America, Europe and Asia;
hence was able during recent visit to
Kauai to make some notes and cornpari-
sons that may interest the residents of
this kingdom.
notwithstanding recent rains | found
the sand on the dune at Mana dry to the
depth OF four or five inches, and when
pushed down the steep incline it gave
out deep base note having tremulous
character This hardly resembles the
barking of a dog, but a sound some
what like it is produced by plunging the
hands into the sand and bringing them
vigorously together. Another way is to
I'LL a long bag three-quarters full of sand.
and then dividing its contents into two
parts, holding one in each hand. to clan
the. two portions together. This I had
found to be good method for testing
the sonorousness Of sand on sea beaches.
A bag of the sand will preserve its
acoustic qualities long time if kept dry
and not too frequently manipulated.
The angle at which the sand lies where
1t falls over the dune is 81 degrees; the
. sonorousness extends several hundred
feet along the dune, being interrupted
by creeping vine that thrives marvel
ously In such soil.
A similar dune of sonorous sand oc-
ours on Nllhau, as has long been known
10 residents OF the island, and it has been
also reported to occur near Koloe.
These observations, simple as they are,
have been of special interest to me. be-
cause they show that the sand of these
Localities forms link between that Of
the sea beaches and that of certain hill
on the Gulf of Suez known as Jebel Ma
gous, and which / visited in April, 1889.
Sonorous sand is of more common occur
renee than generally supposed. 1t is
found on the Atlantic coast of the Unit
ed States from Maine to Florida, on the
Pacific coast, in Europe, Japan, Africa,
Tasmania, ETC., as well as on the shores of
many fresh water lakes In these localities
1t forms areas generally between low
tide and the base of adjoining dunes, and
emlts sounds only when subjected to
friction by the feet and hands or in q
bag as described. At Jebel Nagous, in
Arabia, on the other hand, the sand rests
IN ravine, and produces sound only
when it rolls down the incline (which it
often does spontaneously and fails to re-
spond to kicks and cuffs.
The sand at Mana, as shown, unites in
itself both these acoustic properties. The
angle at which the sand lies at Jebel
Nagous is the same as at Mana, 81 de-
grees being the ''angle of rest" for fine
dry sand. The musical notes obtained
at these far separated localities are also
the same, but in Arabia the incline is
800 feet high, and consequently tn.
sounds are far louder, especially as they
are further magnifed by being echoed
from adjoining cliffs.
The sand at Kauai and Niihau is made
up of fragments of shell and coral, while
that of all other localities known to us
lover 100 in nu1nber) is siliceous. This
shows that the sonorousness is indie
pendent of material. Examination under
the microscope further shows that the
sonorous quality is not connected with
the shape of the grain.
Sonorous sand is distinguished by
being free from fine dust or silt; the in
dividual grains are very uniform in size
1t is very easy to deprive sand of its
acoustic power by mixing little earth
with it or by wetting it. It is difficult,
if not impossible, to restore to sand its
sonorous quality when once "killed."
A number of hypothesis have been
proposed to explain the cause of this Gu
rious property of certain sands. The
prevalent idea in these islands that the
sound is due to the cellular structure of
the sand must be abandoned, since most
sonorous sand is not so constituted, that
of Kauai forming an exception. Some
have attributed the sonorous quality to
saline crusts, others to electricity, effer-
vescence of air Between the particles,
reverberation within subterranean cav
tiles and to solarization, and one author
attempts to explain the phenomena by
writing Of "a reduphcation Of impulses
setting air in vibration in focus Of
echo
These theories DR.. Julien and l reject
for reasons cannot here detail and we
believe the true cause of sonorolsness to
be connected with thin pellicles or films
Of air or of gases thence derived, depos-
tied and condensed upon the surface of
the sand grains during gradual evapora-
ton after wetting b. seas, lakes or rains.
By virtue Of these films the sand grains
become separated by elastic cushions Of
condensed gases, capable Of considerable
vibration, whose thickness we have ap-
proximately determined. The extent of
the vibration and the volume and pitch
of the sound produced we also find to be
largely dependent upon the forms, struct-
ures and surfaces of the sand grains and