>/// and Natural Hirtory, 



10, Ch a of Volcanoes^ with Contributions of Fact* 



I Principles from tin Hawaiian TalandSj Including :i historical 

 iew of Hawaiian volcanic action for the past sixty-seven years, 

 a discussion of the relations of Volcanic [glands to deep-tea 

 topography, and a chapter on Volcanic [gland Denudation, by 

 Jambs D, Dana. 4ik) pp., 8vo. Illustrated by maps of the 

 islands, a bathymetric map of the Atlantic and Pacific oceans, 



and views of cones, craters, a lava cascade-, lava fountain, etc. 

 New York. 1- (Dodd, Mead A: Co.) — This volume com- 



mences with a general account o( volcanoes and volcanic phe- 

 nomena. It illustrates the subject afterward by reviewing the 

 facts afforded by t lie Hawaiian volcanoes, adding to and rear- 

 ranging somewhat the descriptions and discussions that have 

 appeared in tins Journal. That the importance of the Hawaiian 

 volcanoes to the vuloanologisl may be appreciated, we mention 

 here the special points in which they have proved to be the best 

 known source of facts and principles, — citing from the Preface. 



Science has learned, from the Hawaiian volcanoes, of volcanic 

 activity unrestricted by altitude up to fourteen thousand feet; of 

 the possibility of two first-class craters working simultaneously 

 within the area of one mountain dome, and having the loftier the 

 more frequent and the more copious in its outflows, and neither 

 of them ordinarily responsive to the other even when in eruption ; 

 and of the outflow of the heaviest of chrysolitic lavas at various 

 altitudes to the very summit. 



Science has learned from Hawaii more than it knew of the mo- 

 bility of liquid basalt; of the consequent range in flow-angle of 

 basalt-lavas, from the lower limit near horizontality to the verti- 

 cally of a waterfall, and therefore of lava-cones of the lowest 

 angle, and driblet-cones of all angles ; of lava-lakes tossing up 

 jets over their fiery surface like the jets of ebullition, and in 

 other cases playing grandly in fountains hundreds of yards in 

 height; and, consequently, of the absence from the craters of 

 large cinder-ejections. 



It has further learned of a degree of system in the changes 

 within a crater from one epoch of eruption to a state of readiness 

 for another ; of a subsidence, after an eruptive discharge of lava, 

 that has carried down, hundreds of feet, a large part of a crater's 

 floor without a loss of level in its surface; and, following this, 

 of a slow rising of the subsided floor, chiefly through the ascen- 

 sive or up-thrust action of the lavas of the lava-column, and the 

 lifting force taking advantage of the fault-planes that were made 

 at the subsidence; and also of debris-ridges and of debris-cones, 

 one to two hundred feet in elevation, made, by the lift, out of the 

 talus of the pit-walls. 



It has learned that pit-shaped craters are characteristic of true 

 basalt-volcanoes, and a result of the free mobility of the lavas, 

 whether the action in the lava-lakes within be fountain-like or 

 boiling-like ; that floating islands of solid lava may exist in the 

 lakes; that a regular oscillation between fusion and cooling takes 



