458 WISCONSIN STATE AGRICULTURAL SOCIETY. 
As long ago as 1546, theories were formed to explain the 
filling of fissures with mineral matter; and almost as long ago 
as that, scientific men were divided as to whether it was from 
above or below. In the seventeenth century, Werner’s theory 
of descension was introduced to explain the formation and fill¬ 
ing of mineral veins from above. “ The vein-stuff ” (said 
Werner) “arose from a wet precipitate which filled them from 
above; that is, from a wet and mostly chemical solution, which 
covered the region where the fissures existed, and at the same 
time filled the open fissures.” 
Such theories were introduced into scientific mining schools, 
and have tinged the belief of quite a number of professors, 
both in Europe and America, but they have never been 
adopted by practical men, having no adaptation whatever to 
the phenomena of mineral veins. And it is a great satisfac¬ 
tion to know that such theories have lost what little influence 
they may have had in these schools, and are now, not only 
obsolete, but are ranked among the follies of the past. 
The royal school of mines at Freiberg, Saxony, in which 
Werner was a professor, and where he used all the influences 
and appliances at his command to develope his theory, has 
thrown it aside as unsound and worthless. 
We may not be able to explain fully where this material 
filling the fissures ^came from, or by what process it was 
brought into them and formed into veins or lodes; but we 
have the following facts, which will afford some light on this 
question : A mineral vein is an aggregation of mineral matter 
in a fissure, no matter what is its angle or inclination, or the 
character of the rock it traverses. This material is highly 
crystalline, in many cases beautifully crystallized; and most of 
these forms of crystallization we know must be the result of 
chemical deposition from water. Not only the forms them¬ 
selves, but everything around them forbid the supposition of 
crystallization from fusion; and even those we cannot prove 
to be chemical depositions from water, show no reason why 
they may not be. 
I have carefully noticed the contents of mineral veins for 
