34 



SCIENCE. 



[N. S. Vol. V. No. 105. 



water would be sensibly discolored at a distance 

 of 350 meters, while semi-saturation would 

 have been reached only at a distance of 84 

 meters. When the relatively high viscosity of 

 lava is taken into account, assumed by the 

 author as more than 50 times greater than that 

 of water, the rate is found to be still slower; 

 and consequently a sensible impregnation of 

 the lava would extend in a million years to 

 only about 49 meters from the surface of con- 

 tact. Further than this, it has been shown 

 that convection would be to some extent un- 

 avoidable, and, so far as it acted, it would tend 

 to destroy this action of diffusion. Segregation 

 by the separation of the magma into immiscible 

 portions is regarded as the least objectionable 

 method, "but this seems to involve a super- 

 heated, very fluid magma, while the law of 

 fusion and the distribution of phenocrysts in 

 rocks indicate that magmas prior to eruption 

 are not superheated to any considerable extent 

 and are very viscous. ' ' The author concludes 

 that "the homogeneity of vast subterranean 

 masses called for by the hypothesis of differen- 

 tiation is unproved and improbable. The dif- 

 ferences between well-defined rock types are 

 more probably due to original and persistent 

 heterogeneity in the composition of the globe. 

 Hypogeal fusion and eruption tend rather to 

 mingling than to segregation, and transitional 

 rock varieties are not improbably mere fortui- 

 tous mixtures of the diverse primitive, rela- 

 tively small masses of which the lithoid shell 

 of the earth was built up." 



H. S. Washington describes a series of igneous 

 rocks from Asia Minor. These include some 

 augite-andesites from Smyrna and a biotite- 

 dacite from Pergamon. The microscopic char- 

 acters are given in full, and also a number of 

 analyses. M. Carey Lea mentions an experi- 

 ment obtained from a solution of chloride of 

 gold, containing 1 gram to 10 cc, combined with 

 &l<)</o solution of sodium hypophosphite. The 

 result is a solution of deep green color, which 

 is shown to be due to the presence of a small 

 quantity of gold in its blue form, in a state of 

 very fine diflusion, which, together with an un- 

 decomposed solution, gives the effect of green. 

 A. E. Verrill and Katherine J. Bush discuss at 

 length a revision of the genera of Ledidse and Nu- 



culidffi of the Atlantic Coast of the United States. 

 The authors state that a somewhat extended 

 study of the series of deep-sea bivalves belong- 

 ing to these families, dredged off our coast by 

 the U. S. Fish Commission, from 1872 to 1887, 

 has compelled them to revise the known genera 

 and subgenera and to propose several new 

 groups. In view of an unexpected delay in the 

 publication of the report upon these families, 

 which had been completed and fully illustrated, 

 it has seemed desirable to them to publish a 

 brief preliminary account of the classification 

 adopted. The present article is the result. 

 Two plates with twenty-two figures show typi- 

 cal forms with details of the hinge structure. 

 The number closes with the usual abstracts, 

 book notices, an obituary notice of Dr. B. A. 

 Gould, etc.; a note is given to the remarkable 

 meteor of December 4th; also a brief account of 

 a gigantic squid formed on the coast of Florida. 



SOCIETIES AND ACADEMIES. 



BOSTON SOCIETY OF NATURAL HISTORY, 



BOSTON, MASS. 



A GENERAL meeting was held Wednesday, 

 November 18th, 290 persons being present. An 

 account of the work of the Boston party accom- 

 panying the sixth Peary expedition to Greenland 

 was given by Messrs. Barton, Burton and Porter. 



Prof. G. H. Barton gave a narrative of the 

 line of travel and of the general points of in- 

 terest noted during the exploration, describing 

 with some detail the character of the inland 

 ice and the structure and work of the glaciers 

 in the Umanak district. 



Prof. A. B. Burton described the topo- 

 graphic barrenness of the Umanak district ; the 

 abundance of boulders and the stunted growth 

 of the trees was everywhere apparent. With 

 the aid of maps thrown on the screen he showed 

 the stations where magnetic observations were 

 needed, and described at length the results of 

 the magnetic and pendulum work done on 

 the coast of Labrador, on the north shore of 

 Hudson Straits, and in the Umanak district. 

 Prof. Burton gave a detailed account of his 

 study of the Karajak glacier ; the motion of 

 this and of other glaciers was carefully mea- 

 sured. An average of 19 feet in seven days 

 was noted and an interesting observation con- 



