ADVANTAGEOUS DISPOSITION OF METALS. 553 
Had large quantities of metals existed through- 
out Rocks of all formations, they might have 
been noxious to vegetation ; had small quan- 
tities been disseminated through the Body of 
the Strata, they would never have repaid the cost 
of separation from the matrix. These inconveni- 
ences are obviated by the actual arrangement, 
under which these rare substances are occasion- 
ally collected together in the natural Magazines 
afforded by metallic veins. 
In my Inaugural Lecture (page 12) I have 
spoken of the evidences of design and benevolent 
contrivance, which are apparent in the original 
formation and disposition of the repositories of 
minerals ; in the relative quantities in which they 
are distributed ; in the provisions that are made 
to render them accessible, at a certain expence 
place of conductibility, opens a path to the electricity resulting 
from the chemical action, and a voltaic current is formed which 
serves to augment the energy of the chemical action of the two 
bodies. In ordinary chemical actions, combinations are effected 
by the direct reaction of bodies on each other, by which all their 
constituents simultaneously concur to the general effect; but in 
the mode considered by Bccquerel the bodies in the nascent 
state, and excessively feeble forces, are employed, by which the 
molecules are produced, as it were, one by one, and are disposed 
to assume regular forms, even when they are insoluble, because 
the number of the molecules cannot occasion any disturbance in 
their arrangement. By the application of these principles, that 
is, by the long-continued action of very feeble electrical currents, 
this author has shewn that many crystallized bodies, hitherto 
found only in nature, may be artificially obtained. 
