34 TRANSACTIONS OF THE [OCT. 27, 



many persons. Mrs. Holmes, wife of the State Geologist of 

 North Carolina, has observed musical sand on the banks of Cape 

 Fear Kiver, 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 Eiver 

 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. S. N., had previously 

 reported its occurrence on the landing beach at Liberia, West 

 Africa. Mr. Henry C. Hyndman, in a recent letter to Na- 

 ture, calls attention to a mention of sonorous sand by Andrew 

 A. Anderson in his work, "'Twenty-five Years in an African 

 Wagon " (1887) ; the locality therein named is on 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 particles, 

 and has a well-known harsh character by no means musical ; it 

 is sometimes heard when wagon-wheels crush through sand, and 

 in very rare cases this becomes a loud squeak. The second sound 

 is caused, we believe, by oscillations of the particles themselves, 

 protected 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 yields a 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 



