Bead before the Texas Academy of Science , Nov. 1, 1895. 
GENESIS OF CERTAIN ORE VEINS, WITH EXPERIMENTAL 
VERIFICATIONS, 
BY W. H. VON STREERUWITZ. 
Geology, as far as it refers to the azoic ages, is a speculative science; 
the worker in this field has to build conclusions on premises which fre¬ 
quently are also but conclusions. It is a very interesting field, but the 
geologist following up this branch of the science, which is intimately con¬ 
nected with mining geology, is at a certain disadvantage as against the 
worker in stratified formations, in formations of which even the single hori¬ 
zons of every period are distinctly labeled by fossils and ready for system¬ 
atic classification. True, nature now and then kindly allows us to guess, 
and even understand, the secrets of her wonderful workings in rocks and 
minerals, but in most cases denying us the means to reproduce in the 
laboratory on a small scale those phenomena which the geologist meets 
and investigates in mountains and mines. 
One of the principal agents at nature’s command is absolutely denied 
to the student and most skillful experimenter: the length of time, which 
only in few cases may be replaced by increased energy of forces. 
Other agents of equal importance are heat and pressure. No doubt our 
powerful dynamos may produce heat high enough to melt and even to 
vaporize all the elements of which our globe, of which the universe, is 
built; but we have no crucibles, no retorts, that could withstand the heat 
and pressure which may have been required to form rocks and rock con¬ 
stituents. 
Nevertheless, some successful experiments in this direction have been 
made; as, for instance, Daubres, in Paris, produced some of the so-called 
igneous rocks, and changed some into others. 
Very few experiments have been made referring to the origin of ore 
veins and deposits, and less written on this subject than any other geolo¬ 
gical question. Most writers on this subject explain the origin of the 
ore deposits as we find them in the mines by very astute chemical and 
physical theories, in more or less plausible fnanner; and if in metallur¬ 
gical processes we get occasional hints how some ores might have been 
formed, for instance, from the beautiful galena crystals in furnaces, these 
facts do not explain the peculiar, we might say seemingly capricious, ar- 
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