34 TRANSACTIONS OF THE [oor. 27%, 
many persons. Mrs. Holmes, wife of the State Geologist of 
North Carolina, has observed musical sand on the banks of Cape 
Fear River, a few miles above Wilmington, N. C. Mr. A. Sid- 
ney Olliff, writing to Nature, reports sonorous sand at Botany 
Bay, New South Wales, not far from the spot where Capt. Cook 
first landed. Prof. Liversidge, of the University of Sydney, has 
kindly sent us a specimen of sonorous sand from Brown’s River 
Bay, Tasmania. Mr. L. H. Jacoby, a Fellow of this Academy, 
brought us a specimen from Cape Ledo, West Africa. Lieut.- 
Commander Frederick A. Miller, U. 8S. N., had previously 
reported its occurrence on the landing beach at Liberia, West 
Africa. Mr. Henry C. Hyndman, in a recent letter to Va- 
ture, calls attention to a mention of sonorous sand by Andrew 
A. Anderson in his work, ‘‘'l'wenty-five Years in an African 
Wagon ” (1887); the locality therein named ison the west side 
of the Langberg mountain, in West Griqualand, on dunes 500 to 
600 feet in height. 
These notes confirm our views, published in 1884, that musical 
sand is really abundant throughout the world, and has only 
lacked a biographer to bring it before the public. 
In a paper read before the Bournemouth Society of Natural 
Science by Mr. Cecil Carus-Wilson, in 1888, the author, after 
liberal quotations from abstracts of our communications to the 
Academy, announces as his theory that the musical notes result 
from the ‘‘rubbing together of millions of clean sand-grains 
very uniform in size.” This he reaffirms in a recent letter to 
Nature (October 9th, 1890). Dr. Julien and I regard this the- 
ory as insufficient to explain musical sand, but well adapted to 
explain squeaking sand. ‘Two distinct classes of sounds are pro- 
duced by disturbing sand, both undoubtedly due to vibrations. 
The more common sound is caused by attrition of the Parse 
and has a well-known harsh character by no means musical ; 
is sometimes heard when wagon-wheels crush through sand, te 
in very rare cases this becomes a loudsqueak. 'Thesecond sound 
is caused, we believe, by oscillations of the particles themselves, 
pr otected from actual contact by elastic air-cushions, and this is 
decidedly musical in tone. 
Musical sand yields notes by friction only when dry ; squeak- 
ing sand yieldsa harsh, shrill sound (reminding one of the cry 
of a guinea fowl), best ‘when moist. This latter variety is very 
rare ; we have collected, by correspondence and in person, more 
than 600 samples of sand from around the world, and musical 
sand seems to be comparatively common ; but only two localities 
of squeaking sand are known to us, both in so-called boiling 
springs—one in Maine and the other in Kansas. A very small 
