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tery. If a liquid, as water, for instance, is acted upon by the current, it 
is decomposed, and the oxygen is found at, or transferred to, the positive 
pole. To deny such an agency in the filling of veins in all cases, would 
certainly be wrong ; but to attribute the filling of all veins to that agen- 
cy, is equally wrong. Now, experiment clearly proves that the most 
common mineral substances resist entirely the action of this form of elec- 
tricity, except under certain conditions. All bodies, in a solid state 
belong to this class ; fluidity is an essential condition. This, it is true, 
may be an aqueous or igneous fluidity. If there is an open fissure 
filled with water, or any fluid, holding, in solution, mineral matter, it 
may be deposited or separated from it by galvanic agency. It would 
appear as an essential condition that a fissure should previously exist. 
Now, if we suppose igneous fluidity, either of the rock or the mineral 
in question, or both, it may be galena, or iron, as either have a condi- 
tion which is incompatible with the formation of a fissure, so long as 
fluidity exists ; or we have a condition in which it becomes unnecessa- 
ry to call on the aid of an electro-motive power. If the rock is in a 
state of fusion, no fissure can be formed, into which a metallic sub- 
stance can be transferred, so long as that condition exists ; and when 
it becomes solid, it loses the essential condition requisite |for electro- 
motive action ; but while it is in this state of igneous fusion, the parti- 
cles are in a state which are favorable for movements in obedience to 
the power of attraction ; and hence, masses of mineral matter may, 
under this condition, form, but the masses are not veins. Again, if 
the mineral itself is in a state of igneous fusion, and there is a fissure 
to receive it, then the very power which caused this fusion, is adequate 
to the filling of it, either by injection, while in a melted state, or by 
sublimation. 
It will be observed that the great objection to the filling of veins by 
electro-magnetic agency, is, the want of a state in which that agent 
can exert its powers, that condition or state being one of liquidity ; so 
long, therefore, as a substance is solid, or in an aeriform state, it is just so 
long unacted upon by this agent.* Besides, in favor of igneous agency 
in the filling of veins, we have many positive examples in the case of 
dykes of green-stone, lava, &c. 
If the above is true, we may conceive that the error comes from the 
general and exclusive character of the theory. The filling of a vein, in a 
*ThuS; water, though decomposed by galvanism, is not at all acted upon when fro. 
zen, or in a solid state. 
