September 7, 1883.] 



SCIENCE. 



325 



The following are the records of tests of New-Eng- 

 land granites : — 



.Vfter discussing several supposable causes of error, 

 and showing that they could not have applied to the 

 present case, tlie author proceeds to suggest causes 

 why the Minnesota granites may be stronger than 

 those of Xew England. He thinks those of the west 

 may have been less changed by decay. The lateness 

 of the glaciation to which they were cxjiosed may 

 have left them comparatively fresh through the recent 

 removal of a considerable thickness. On this point 

 we shall be more certain when the glacial moraines 

 have been fully traced from east to west, and the 

 western analogues are determined. 



The siuglug beach of Manchester, Mass. 



BY A. A. JliLIKX OF NEW YOIiK AND II. C. BOLTON 

 OF UAHTFORD, CONN. 



Sands were taken from the so-called ' singing beach' 

 on the coast of Massachusetts, near Manchcster-on- 

 the-Sea, and subjected to microscopical examination. 

 In this beach, the felspathic rocks are intersected 

 by numerous dykes of igneous rocks, among which 

 porphyritic diorite is noticeable. The plienomenon 

 which gives rise to the name of the beach is confined 

 to the portion of sand lying between the water-line 

 and the loose sand above the reach of ordinary high 

 tide. Portions emit the sound; but closely contigu- 

 ous areas fail to do so, or answer feebly. The sound- 

 ing sand is near the surface; at the depth of one or 

 two feet it ceases, perhaps because of moisture. The 

 sound is produced by pressure, and may be likened to 

 a subdued crushing; it is of low intensity and pitch, 

 is not metallic nor crackling. It occurs when the 

 sand is pressed by ordinary walking, increases with 

 sudden pressure of the foot upon the sanil, and is 

 perceptible upon mere stirring by the hand, or even 

 plunging one finger and removing it suddenly. It 

 can be intensified by dragging wood over the beach. 



The authors review and cite very fully the litera- 

 ture of the subject, giving in full a description of the 

 singing sands of the islaiul of Kaiii, one of the Ha- 

 waiian group. That gives a sound as of distant 

 thunder, when any tiling of weight is dragged over 

 it. Dampness preveiils the sound. That sand is 

 calcareous. Hugh sillier cites similar instances at 

 Jebel Xakoiis in .\rabia Petrea, and Keg Rawan near 

 Cabul. Those are silicious sands. The sounds were 

 a sort of bmnming. 



In Churchill county, Xevada, a similar phenomenon 

 is described with regard to a sand-hill, as like the 

 sound of telegr.aph-wires when wind blows them. 



Tiie authors also review and characterize the vari- 

 ous sands of different mineral origin. 



To explain the sonorous peculiarity of the sand, 

 several theories are considered. That of e<|ualily, or 

 of the unequal size of the grains, is rejected. Cellu- 

 lar structure has been supposed, but is not found in 

 the present instance. Effervescence of air between 

 moistened surfaces does not apply to this case. .So- 

 norous mineral, such as clinkstone, is not present. 

 There is no evidence of electrical phenomena being 

 concerned. The hypothesis adopted is that the sand, 

 instead of being, as ordinarily, composed of rounded 

 particles, is made up of grains with flat ami angular 

 surfaces. In the present instance, the plane surface 

 of felspar is apparent in many of the grains. Prob- 

 ably a certain proportion of quartz and felspar grains 

 is adapted to give the sound, while less or more of 

 either component would fail of the result. 



Dr. Bolton has himself examined a sand of similar 

 quality, on the island of Eigg in the Hebrides, and 

 has described its properties. That is largely calcare- 

 ous. Its constitution is a mixture of large and small 

 grains, the larger ones being roumlcd quartz, ilany 

 small, angular fragments of quartz are also con- 

 tained, and many dark granules of chert, the last 

 being about three or four per cent of the whole, and 

 having a cellular structure. 



It is concluded, that the sound is produced either 

 by the intermixture of grains having cleavage planes, 

 or of grains with minute cavities. The paper ends 

 with a table of the physical structure of the sands of 

 many localities. 



( PA L EON rOL OGICA L PA PEIl S. ) 



PreUmmary note on the microscopic shell- 

 structure of the paleozoic Brachiopoda. 



BY JAMKS IIALI, ol' ALHANY, N.V. 



In the earlier studies of the IJraeliiopoda. the nu- 

 merous species were referred to few generic terms, 

 determined from their perforated apex and external 

 form, and later from the study of the interior as 

 these became known. The author said, that from 

 time to time, as these characters had become known 

 to him from the study of large collections, he had 

 found it necessary to propose the separation of eigh- 

 teen new generic forms from those previously known 

 in this class of fossils. Other authors had also pro- 

 posed new generic terms, until the list had become 

 many times greater than it was twenty-five years ago. 



