A SUMMER RAMBLE AMONG THE HEBRIDES. 65 



sible that it may. I have, however, little doubt, that from 

 small quantities the sounds evoked by the foot on the shore 

 may be reproduced : enough will lie within the reach of ex- 

 periment to demonstrate the strange difference which exists 

 between this sonorous sand of the Oolite, and the common 

 unsonorous sand of our sea-beaches ; and it is certainly worth 

 while examining into the nature and producing causes of a 

 phenomenon so curious in itself, and which has been charac- 

 terized by one of the most distinguished of living philosophers 

 as " the most celebrated of all the acoustic wonders which 

 the natural world presents to us." In the forthcoming num- 

 ber of the " North British Review," which appears on Mon- 

 day first,* the reader will find the sonorous sand of Eigg re- 

 ferred to, in an article the authorship of which will scarce 

 be mistaken. " We have here," says the writer, after first 

 describing the sounds of Jabel Nakvus, and then referring to 

 those of Eigg, " the phenomenon in its simple state, disem- 

 barrassed from reflecting rocks, from a hard bed beneath, and 

 from cracks and cavities that might be supposed to admit the 

 sand ; and indicating as its cause, either the accumulated 

 vibrations of the air when struck by the driven sand, or the 

 accumulated sounds occasioned by the mutual impact of the 

 particles of sand against each other. If a musket-ball passing 

 through the air emits a whistling note, each individual par- 

 ticle of sand must do the same, however faint be the note 

 which it yields ; and the accumulation of these infinitesimal 

 vibrations must constitute an audible sound, varying with 

 the number and velocity of the moving^ particles. In like 

 manner, if two plates of silex or quartz, which are but large 

 crystals of sand, give out a musical sound when mutually 

 struck, the impact or collision of two minute crystals or 

 particles of sand must do the same, in however inferior a 

 degree ; and the union of all these sounds, though singly 

 * March 31, 1845. 

 



