October 19, 1900.] 



SCIENCE. 



609 



Ordinarily corrosion, erosion and hydrostatic 

 pressure worli simultaneously in cave-making. 

 The acids eat into the softer portions of rock, 

 leaving the harder parts as gravel, or sand, 

 which the whirling or flowing water uses to 

 grind a channel for drainage to an outlet. 



M. Martel finds limited subterranean reser- 

 voirs, and also sheets of water held by satura- 

 tion in mellow soils and porous strata, but de- 

 nies the existence of vast bodies of water 

 ('nappes d'eau'), such as are insisted on by 

 certain ancient and modern authorities — even 

 as recently as 1897 — in order to explain the 

 phenomena of artesian wells. He describes 

 the sinking and resurgence of streams ; and 

 also a system of siphonage, which, as he 

 remarks, belongs to hydrology rather than to 

 speleology. Certain caves, however, are really 

 but the channels of underground rivers whose 

 waters have found some other bed. 



The chapter on 'Abimes,' or natural pits, is 

 peculiarly interesting, although, as the author 

 admits, their origin has been an occasion of 

 'interminable controversy.' We cannot now 

 follow him through his elaborate discussion of 

 the theories of glacial grinding, of geyser chim- 

 neys, of interior excavation, the ' theorie du 

 jalonnement' (i. e. , that they are drainage out- 

 lets for ancient lakes), and other theories. For 

 this and much other interesting material the 

 reader is referred to Martel's great work, ' Les 

 abimes,' pp. 576, Paris, 1894. The theory 

 finds favor that the abimes are generally due to 

 exterior causes, working downward from the 

 surface, rather than to interior forces. This is 

 especially evident in the ' avens ' that pierce 

 the vast limestone plateaus, known as ' causses ' 

 — a term derived from the Latin 'calx.' Some 

 of these avens drop vertically for from 200 to 

 700 feet, and then expand into vast chambers, 

 occasionally with bodies of water, but often 

 ending in numerous fissures of drainage. 



M. Martel gives a list of abimes actually meas- 

 ured and known to be more than 200 meters in 

 depth. The deepest of all is a perilous pit named 

 in honor of its discoverer, M. David Martin, and 

 located near Saint Disdier, amid the Hautes 

 Alpes, at a point about 5,000 feet above the 

 sea. Martel descended more than 1,000 feet 

 vertically, and estimated the entire depth at 



about 1,600 feet. The writer of this review had 

 the satisfaction personally^ in 1897, of witness- 

 ing Martel's exploration of the Aven Armand, 

 in Loz6re, a pit more than 600 feet deep. The 

 rope ladders, portable telephones and other ap- 

 paratus made a striking display. In other pits 

 that were intersected by streams a curious plan 

 was taken for tracing the waters by discoloration 

 by flourescein. 



After describing stalactites, stalagmites and 

 other forms of drip -stone, whose tendency is to 

 obliterate caverns, and whose rate of growth 

 has been recorded as indicating the age of the 

 excavations In which they exist, M. Martel 

 states the difficulties of the problem fairly, and 

 concludes that it is impossible to afBrm, in 

 the actual state of our knowledge concerning 

 subterranean channels, just when they began 

 to exist ; but he suggests the middle of the Ter- 

 tiary epoch. 



Particular attention is paid to the temperature 

 of caverns, the purity or impurity of cave atmos- 

 phere, and the contamination of springs and sub- 

 terranean reservoirs in relation to the public 

 health. Natural ice-houses, and the theories of 

 their formation, furnish material for an interest- 

 ing chapter. Four causes are assigned, namely, 

 the shape of the cavities, free access of snow 

 in winter, altitude, and evaporation by currents 

 of air. In this connection researches and ad- 

 ventures amid Alpine snow-pits are described. 

 Cavern minerals are diversified. Among those 

 mentioned are the various metallic ores, clays, 

 carbonates, phosphates, and salts. Brilliant 

 colors are often given to stalactites by copper 

 and other metals. 



Kecent prehistoric explorations have been 

 richly rewarded by relics found in cliff- dwell- 

 ings and subterranean temples. Still more an- 

 cient are the remains of the paleolithic, neo- 

 lithic and bronze ages. Many of the most 

 noted of the inhabited caves and grottoes are 

 mentioned by name. Living troglodytes are 

 described, and also underground cemeteries, 

 from which hundreds of human skeletons have 

 been exhumed. Discoveries In the United 

 States are by no means overlooked, particular 

 mention being made of those in Pennsylvania, 

 Indiana, Kentucky and Tennessee. 



Subterranean fauna and flora, their origin. 



