324 Scientific Intelligence. 



place at times in the thin crust of lava-lakes; that the solid lava 

 of the margin of a lake may be re-fused, and also even the mass 

 of a floating island, and the blocks of a debris-cone until the cone 

 has wholly disappeared. 



It has discovered that solfataric action, or that of the hot 

 vapors in lava-caverns, may include the recrystallizing: of basalt, 

 therein making it into long, stony pipe-stem stalactites and 

 stalagmites, having cavities lined with transparent crystals of 

 augite and labradorite, besides octahedrons of magnetite. 



It has obtained evidence, also, that the greatest of eruptions 

 may occur without the violence or the noise of an earthquake, 

 and without an increase of activity in the crater; that in place of 

 an increase there may be a sudden extinction of the fires, all. light 

 and heat and vapors disappearing as soon as the discharge begins ; 

 of the greater frequency of eruptions during the wetter season of 

 the year; of the agency of fresh water from the rains (and 

 snows) in the supplying of steam-power for volcanic action ; of 

 the full sufficiency of water from this source without help from 

 the ocean — fresh water being as good as salt for all volcano pur- 

 poses; and further, of a great augmentation of the activity so 

 produced with the increase in altitude of the working crater. 



These are facts from Hawaii — and not all that might be cited — 

 that have not yet been made out from the investigation of other 

 volcanoes, not even the best known, Vesuvius and Etna. 



The work closes with a chapter of over twenty-five pages on 

 denudation among volcanic islands in the Pacific, containing 

 also some facts from the author's observations in Australia, taken 

 chiefly from his Geological Report of the Wilkes Exploring 

 Expedition published in 1849. 



11. The Geological Record for 1880-1884; Edited by Wil- 

 liam Topley and Charles Davies Sherborn. Vol. II, Physical 

 and applied Geology, Petrology, Meteorites, Mineralogy, Mineral 

 Waters, Paleontology, General Maps and Sections. 563 pp. 8vo. 

 London, 1889 (Taylor & Francis). — This valuable volume, the 

 contents of which are given in the title, appeared a few months 

 since ; 'with volume I before issued it completes the Geological 

 Record for the five years named. The usefulness of such a work 

 will be appreciated even by those who do not fully understand 

 the amount of labor it has cost. 



12. 2 y abellarische Uebersicht der Miner alien nach ihren hrys- 

 tallographisch-chemischen Beziehungen geordnet von P. Groth, 

 3d edition, 168 pp. Braunschweig, 1889 (F. Vieweg & Son). — Few 

 works upon Mineralogy have contributed so much to the progress 

 of the science as the Tables of Professor Groth, of which the ad 

 edition is now issued. They present in clear and comprehen- 

 sive manner the successive groups of minerals, showing the re- 

 lation in composition and axial ratio of the individual species 

 belonging to each. The author's profound knowledge and keen 

 mind have enabled him to throw light upon many obscure points 

 and to the advanced worker as well as to the student the Tables 

 are constantly suggestive and helpful. 



