THE METAMORPHISM OF ROCKS. 
235 
of which have a regularity and symmetry in their grouping which 
it is impossible to attribute to successive infiltrations through 
an orifice, merely imaginary in most cases. Electro-telluric 
actions play a considerable part in the formation of the con- 
cretionary lodes, which, according to De la Beche, can only 
be considered contemporaneous with the rocks in which they 
occur. The same remark applies, also, to the segregated lodes 
which Weissembach and English geologists explain as a group- 
ing of the particular minerals disseminated in the containing 
rocks. Admitting that the metals and other substances which 
fill the rents and fissures in the earth’s crust, and also the waters 
which have carried them, do not exclusively originate from the 
interior of the earth, but from the whole of the surrounding 
mass, from the surface to the lowest part of the rent or fis- 
sure ; and further, that by the slow and successive entrance of 
these substances as well as by the circulation of the waters, and 
other previously mentioned causes, electrotelluric currents have 
been produced, all the phenomena of metamorphism, as regards 
the lodes, can be explained, and thus the greatest difficulties 
which this arduous problem presents can be made to disappear. 
The comparative greater richness of lodes running across the 
stratification than of those parallel to it, and also the well-known 
fact of an increased richness at the crossing of two lodes, can be 
explained by a relative greater display of electrotelluric action. 
The reason why all the phenomena are attributed to the 
electrical force, which until now have been explained by mo- 
lecular action, electrical repulsion, chemical affinity, and other 
causes, is the author’s belief in the unity of the various natural 
forces. If physicists of great distinction have now arrived at 
the conclusion to attribute the light and heat emanating from 
the sun to continuous electrical discharges in his photosphere, 
as well as in his interior mass, one can well ascribe to electricity 
the actions which take place in the metamorphism of rocks, 
instead of considering it onty, according to some geologists, as 
a secondary force, because heat, pressure, and other modes of 
force, produce electricity. Electricity, by itself, can not only 
originate these, but also other manifestations of molecular mo- 
tion. In the same manner as the immense number of genera- 
tions of infusorial animals have succeeded in building up monu- 
ments in rock, in comparison with which the grandest human 
constructions are mere playthings, the almost impercep- 
tible electrical currents which exist in the earth’s shell are 
able, by their number and continuity, to produce changes 
which neither man is able to bring forth, even when aided by 
the most powerful resources of science, nor nature herself could 
exceed, should she prefer to give us proofs of her power by 
changing the face of the earth by means of terrible cataclysms. 
