A. E. Hunt— The Age of the Earth. V27 



veins, Phillips pointed to hot salt-springs transforming the rocks at 

 considerable though accessible depths, Daubree relied on experiment, 

 while I have been impressed by the characteristics of the vein rocks 

 of Dartmoor with their abundant sodium (as chloride and silicate), 

 and with the chlorite, amphibole, and albite of the green schists. 



The conclusions of De la Beche seem the most noteworthy, seeing 

 that he was necessarily ignorant of the fact that the vein rocks of 

 Devon and Cornwall are charged with salt and brine. In 1839 

 that acute observer wrote — "There is, therefore, nothing imreason- 

 able in supposing that a large proportion of the Cornish and Devon 

 fissures, now wholly or in part filled up, were opened either beneath 

 the sea or in such situations that portions of them were so placed 

 that it entered freely into them " (Eeport on Geology of Cornwall 

 and Devon, p. 378). Subsequently De la Beche cites an instance 

 of water filtrating through hard basalt, filling its internal cavities 

 with liquid, and setting iip crystallization of ' mesot3'pe ' (loc. cit., 

 p. 392). In 1851 De la Beche touches on the chemical combinations 

 of the chlorides in the fissures (Geol. Observer, p. 770). 



In January, 1873, the late Mr. J. A. Phillips read a most interesting 

 paper to the Royal Society, which was subsequently communicated 

 to the Philosophical Magazine. In it the author discusses the 

 composition and origin of the waters of a salt-spring at Hiiel Seton 

 mine, with a chemical and microscopical examination of certain 

 rocks in its vicinity. The water is shown to be derived from the 

 sea, and to enter into chemical combination with the minerals of 

 the rocks through which it passes, producing brown hornblende, 

 pale-green actinolite, and chlorite. Another salt-spring, in the now 

 abandoned Huel Clifford mine, was 1,320 feet below the sea, and 

 issued at a temperature of 125° F. As Mr. Phillips does not refer 

 to De la Beche, he seems to have overlooked De la Becho's views, 

 just as I unfortunately overlooked at first both De la Beche and 

 Phillips. The result, however, is that all three identical conclusions 

 were arrived at independently, and all on different grounds. Had 

 De la Beche lived to learn that the quartz in his fissures actually 

 contained brine and crystals of salt, and that the felspar of his veins, 

 instead of being the orthoclase of the main mass, was triclinic, and 

 more or less a soda-felspar, he would have realized with what 

 unerring sagacity he had hit his mark. 



In 1880 Daubree published his invaluable '■ Geologie Experi- 

 nientale," of which work the third chapter is headed—" Experiences 

 sur la possibilito d'une enfiltration capillaire au travers des matiores 

 poreuses." 



Daubree shows experimentally that bottom heat greatly accelerates 

 the passage of water through rocks in the face of a strong counter- 

 pressure of steam. He incidentally admits that such water may 

 be salt water, and that it would be capable of producing great 

 mechanical and chemical effects. But this is incidental ; his object 

 is to explain the origin of volcanic steam, not to follow up the new 

 combinations of the sodium which the steam leaves behind in the 

 bowels of the earth. 



