The morning call., 1890-07-09
" BARKING SANDS"
Results of a Savant's Investiga.
ti0n in the Sandwich Islands.
The Curious Property Possessed by the Sand
Dunes of Kauai, Niihau and Other
Parts If This Little Kingdom.


are mentioned in the works of several tray
elers in the Hawaiian Islands, and have a
worldwide fame as natural curiosity; as
rule, however, the printed accounts are
meager in details and show the authors to
have been unacquainted with similar phe-
nomena elsewhere.
Join tly with DR.. Alexis A. Julien of Co.
lumbia College, New York, l have been
studying the properties of sonorouS sand
for long time and have visited many To-
calties in America, Europe and Asia;
hence L was able during a recent visit to
Kauai to make some notes and comparisons
that may interest the residents of this king
dom.
Notwithstanding recent rains l 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 a deep
bass note having a tremulous character
This hardly resembles the barking" of a
dog; but sound somewhat like it is pro-
duced by plunging the hands into the sand
and bringing them vigorously together.
Another way is to fill a long bag three
quarters full of sand and then, dividing its
contents into two parts, holding one In each
hand, to clap the two portions together.
This had fOurd to be good method for
testing the
SONOROUS ESS VI BAND
On sea beaches. A bag of the sand will
preserve its acoustic qualities a long time if
kept dry and not too frequently manipu-
lated. The angle at which the sand lies
where it falls over the dune is 80; the
son0rousnesS extends several hundred feet
along the dune, being interrupted by a
creeping vine that thrlyes maryel0usly in
such a soil.
A similar dune of sonor0us sand occurs
on Nihau. as has long been known to resi-
dents OF the island and it has been also re-
ported to occur near koloe.
These observations, simple as they are,
have been of special interest to me. because
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 NagOus, and
which l visited in April. 1889. Sonor0uS
sand is of more common occurrence than
generally supposed. 1t IS found gu the At
lantic coast of the United 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 it forms areas generally
between low tide and the base of adjoining
dunes, and emts sounds only when sub
jeeted 10 friction by the feet and hands or
III bag as described. At Jebel NagouS in
Arabia, on the other hand, the sand rests in
a rayine and produces sounds only when 1t
rolls down the incline, which 1t often does
spontaneously, and fails to respond to KICKS
and cuffs. The sand at Mana, as shown,
unites in itself both these acoustic proper
ties. The angle at which the sand lies at
Jebel Nagous is the same as at Mana, 81
being the "angle of rest" for fue dry sand.
THE MUSICAL NOTES
Obtained at these far separate localities are
also the same; but in Arabia the incline is
800 feet high, and consequently the sounds
are far louder, especially as they are further
magnifed by being echoed from adjoining
cliffs.
The sand at Kauai and Nihau is made up
of fragments of shells and coral, while that
of all other localities known to US (oyer 100
in number is siiceous. This shows that
the sonOrousness is independent of ma
terial. 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 individual
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 wet
ting it, 1t is difficult, if not impossible, to
restore to sand its s0norous quality when
once killed"
a number of hypothesis have been
proposed to explain the cause of this curious
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 Sonor0uS sand Is not
so CONSTITUENT, tUaI Vi hautl lOTuln5 Ill
exception. Some have attributed the sonor-
Gus quality to saline crusts, others to cleo
tricity, effervescence Of air between the
particles, reverberation between subter-
fanean cavities aud To soarlZatiOn; and one
author attempts to explain the phenOm-
enOn by writing of "a reduplicatiOn of
impulses setting air in vibration in focus
of echo" These theories DR.. Julien
and L reject for reasons | can
not here detail, and we believe
the true cause of sOnorousness to be con-
nected with thin pellicles or films of air or
of gases thence derived, deposited and con-
densed upon the surface of the sand grains
during gradual evaporation after wettng
by seas, lakes or rains. By virtue Of these
films the sand grains become separated by
elastic cushions OF condensed gases, capa-
BILE of considerable vibration, whose thick
ness we have approximately determined.
Tie extent of the vibration aud the volume
and pitch of the sound produced we also
find TO be largely dependent upon the forms,
structures and surfaces of the sand grains.
and especially upon their purity or freedom
from fine silt or dust.
We have shown that the pitch of the
musical notes obtained on sea beaches is
proportional TO the mass of sand moved,
the greater the mass the lower the zones;
on the dunes of Kauai and Niihau the same
holds true. Those who wish to learn more
details ct our investigations can ind alb
stracts of three papers read before the
American Association for the Advancement
Of Science in the proceedings for 1888, 1854
and 1885,
1u conclusion, take pleasure in express
ing my thanks to Mr.. Valdemar knudSsn
for valuable information, and to Mr.. II. p
Faye for hospitality and kind aid in my eX-
animation OF the Nohili. | am also under
great Obligations to Mr. George 5. Gray of
Nilhau for generous hospitality in their
island home.-H. Z. BOLTON, in Honolulu
INN nor lal a