30 TRANSACTIONS OF THK [OCT. 27, 



about three miles east of Koloa, Kauai; this I did not visit, but, 

 prompted by information communicated by Hon. Vladimar 

 Knudsen, of Waiawa, I crossed the channel to the little-visited 

 island of Niihau. On the western coast of this islet, at a place 

 called Kaluakahua, sonorous sand occurs on the land side of a 

 dune about 100 feet high, and at several points about 600 to 800 

 feet along the coast. On the chief slope, 36 feet high, the sand 

 has the same mobility, lies at the same angle, and gives when 

 disturbed the same note as the sand of Kauai, but less strong, 

 the slope being so much lower. This locality has been known 

 to the residents of the island for many years, but has never been 

 before announced in print. This range of dunes, driven before 

 the high winds, is advancing southward, and has already cov- 

 ered the road formerly skirting the coast. 



The observations made at these places are of especial interest 

 because they confirm views already advanced by Dr. Julieu and 

 myself with regard to the identity of the phenomena on, sea- 

 beaches and on hillsides in arid regions (Jebel Nagous, Rig-i- 

 Rawan, etc.). The sand of the Hawaiian Islands possesses the 

 acoustic properties of both classes of places ; it 'gives out the 

 same note as that of Jebel Nagous when rolling down the slope, 

 and it yields a peculiar hoot-like sound when struck together in 

 a bag, like the sands of Eigg, Manchester, Mass., and other sea- 

 beaches — a property that the sand of Jebel Nagous fails to pos- 

 sess. These Hawaiian sands also show how completely inde- 

 pendent of material is the acoustic quality, for they are wholly 

 carbonate of lime, whereas sonorous sands of all other localities 

 known to us (now over one hundred in number) are silicious, 

 being either pure silex or a mixture of the same with silicates, 

 as feldspar. 



In 1875 Dr. James Blake, of San Francisco, examined micro 

 scopically a specimen of the Kauai sand sent him by Mr. Frink, 

 and ascribed its acoustic qualities to the cellular cliaracter of the 

 grains. This condition, however. Dr. Julien and I find to be 

 exceptional, since most sonorous sand is quartzose, and we believe 

 the gaseous-film theory, already announced to the Academy, ap- 

 plies equally to sonorous sand of diverse form, composition, and 

 origin. 



A specimen carried away in a bag, and another shipped over 

 land in a keg, have both preserved their acoustic qualities up to 

 date. 



[The speaker exhibited specimens, and obtained a low hoot 

 like sound by clapping together sand confined in a bag. The 

 subject was also illustrated by numerous original photograj^hs 

 (projected on a screen) of the Nohili, and of scenery on the 

 island of Kauai.] 



