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Soutli America to the Fellows of the Geological Society in 
1843, accompanied with large sections of the Andes. I then 
showed, by means of real geological sections, that the primary 
slates were not sedimentary beds, but the result of a semi- 
crystalline action, and that the structure presented a most 
beautiful geometrical order ; that the crystalline rocks were 
ever active, and that the whole series crystallized from water, 
and did not present any indication of igneous action or dry 
heat. These views appeared so novel at the time that but few 
considered them worthy of attention. I then published the 
results of my investigations under the title of “ Geology and 
Magnetism,”* so as to place them on record. 
In 1850 I again, on my return from South America and the 
Isthmus of Panama (which I had been surveying), read a 
paper at the Geological Society, reiterating my former 
opinions, on the structure of the primary rocks and their 
aqueous character. An abstract of the paper was published 
in the Journal of that Society. My views were again strongly 
opposed, but more especially as regards the aqueous nature of 
the granite. I then saw it was useless to bring forward 
such geological facts in opposition to the prevailing igneous 
theory. Nevertheless, I again brought the subject forward 
in a long paper, with abundance of illustrations, before the 
geological section at the Meeting of the British Association at 
Glasgow in 1855 ; also in the Institution of Civil Engineers, 
where it gave rise to a discussion, which was prolonged for 
three evenings. This paper and my general views were much 
appreciated by mining engineers, who were acquainted with 
the true character of the rocks below. About that time, or 
soon after, Messrs. Daubree and Bischoff made known their 
observations on hydrothermal action, or the influence of water 
in the formation of rocks. The result of their investigations 
was that the minerals which enter into the composition of 
granite were admitted not to have been formed by crystal- 
lizing from a state of fusion, but that they have been derived 
from liquid solutions, or formed in the wet way. 
Professor Ramsay was one of the most determined opponents 
of my views regarding the aqueous nature of the granite. It 
is but justice to that gentleman to state that, in compliment- 
ing Messrs. Daubree and Bischoff on the result of their 
investigations, when President of the Geological Society in 
1862, he remarked that “he could not pass over the papers and 
observations of one of their own members (Mr. Hopkins) on 
* Geology and Terrestrial Magnetism. -By Evan Hopkins, C.E., F.G.S., 
(Loud. : Taylor & Francis, Red Lion Court, Fleet Street.) 
