88 Mr. T. H. BoUand— Mica-hearing Pegmatites. [July, 1899.] 



on cooling, and in wliicli the consolidation is rapidly accomplished, the 

 crystals formed aie necessarily small, as they always are for instance 

 at the selvages of basic dykes, the converse being the case when the 

 magma retains its fluidity for a long period. With what Reyer calls 

 a hydatopyrogenelic (aquo-igneous) magma the latter condition is 

 possible, for there is then a small difference between the temperature of 

 the magma and of the rock into which it is injected, and consequently a 

 very slow dissipation of heat. The reduction of temperature is still 

 more retarded on account of the great specific heat of the water con- 

 tained in an aquo-igneous melt ; for to reduce water by one degree in 

 temperature involves the equivalent rise of some three times the amount 

 of average rock. The water, therefore, which becomes concentrated in 

 the magmas that form our pegmatites explains the high degree of 

 fluidity and consequent injection to great distances of very thin films, 

 as well as the remarkably well crystallized condition in which such 

 thin veins of pegmatite are invariably found. 



6. Biddies current in Behir.—By Sarat Chandra Mitra, M.A., 

 B.L. Communicated hij the Anthropological Secretary. 



7. Heroic Godlings of Malabar. — By S. Appadorai Iter. Communi- 

 cated by the AntJiropological Secretary. 



The papers will be published in the Journal, Part III. 



