1884. 75D Trans. N. Y. Ac. Sci. 
composed, they may be the following : limestone and recent corals, as 
in the Sandwich Islands ; nearly pure quartz, as on Lake Champlain ; 
quartz, with some feldspar, as at Manchester, Mass. ; quartz, with a 
little iron-ore and garnet, as on the shores of Lake Michigan and 
along our Atlantic coast, south of New England; and quartz with a 
small intermixture of chert, as in the Hebrides. The form of the 
grains may be largely angular or tabular, as at Manchester ; more or 
less rounded, as at nearly all the localities mentioned ; or even nearly 
spherical or oolitic, as on Lake Champlain. The texture may be cel- 
lular, in part, as in the Sandwich Islands and the Hebrides, but is in 
most cases compact and solid. 
Sounds ordinarily heard in nature may originate in animate agents 
—animals and plants—or in inanimate objects. In the latter, the 
agencies which produce sounds may be classified as physical, e.g., 
the rending of rocks or ice by frost; electrical, ¢.g., the lightning ; 
chemical, ¢.g., the decomposition and explosion of pyrites ; mechani- 
cal, e.g., movements in bodies of air, z.e., the winds, or movements in 
water, the waves and surf; and volcanic action. There are also 
sounds of greater rarity which are produced in mineral matter, such 
as by falling blocks of rock, the flowing of lava-streams, and the 
special subject under discussion, the motion of loose sands by the 
winds, waves, or animate agents. The louder and common sounds in 
nature thus originate in a variety of causes, and it seems probable 
that more than one condition is concerned in the modification of those 
heard in the sonorous sands. Various modes of vibration may be 
produced by the grating of cleavage planes, as in the Manchester 
sands, or the slipping of curved polished surfaces, as in many other 
instances ; but the reverberation within minute cavities may be also 
involved in the peculiar and louder sounds which have been heard in 
the sands of Kauai and Eigg, which contain cellular grains, and the 
same may be found true in the similar sands of Arabia and Nevada. 
Prof. H. L. FAIRCHILD inquired whether a loss of the sound oc- 
curred on the removal of the Manchester sand from that locality, 
and whether the power of emitting the sound was retained by the sand 
in a dry room. 
Dr. BOLTON stated that he had found that the sonorous sand of 
Eigg had lost its peculiar property when carried a few weeks in a cloth 
bag. He had baked the sand of Manchester in an oven, but found 
that it did not then regain its sonorous character. 
[Dr. BOLTON here tested again the sample of sand from Manches- 
ter, which had emitted the sound a half hour before and had been since 
lying exposed to the dry air of the warm room, but the sand now re- 
fused to emit any sounds whatever. ] 
