1884. 75 Trans. N. Y. Ac. Set. 



composed, they maybe 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.£-., 

 the rending of rocks or ice by frost ; electrical, e.^., the lightning ; 

 chemical, e.;^., the decomposition and explosion of pyrites ; mechani- 

 cal, e.g., movements in bodies of air, i.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.] 



