A. Geikie—Archeean Rocks of the Wahsatch Mts. 368 
that the first two of these are the only elements of which we 
have yet any certain evidence in the nebula, it will be seen 
that the speculation of Lavoisier is really an anticipation of that 
view to which spectroscopic study has led the chemists of to-day. 
The three elements named by him are those which, in the forms 
of air and watery vapor, make up nine hundred and ninety-nine 
thousandths of ‘the atmosphere which, in accordance with our 
hypothesis, constitutes the interstellary medium. It was in 
view of all these considerations that the writer in 1874 ven- 
tured to say that “the nebule and their resultant worlds may 
be evolved by a process of chemical condensation from this 
universal atmosphere ; to which they would sustain a relation 
somewhat analogous to that of clouds and rain to the aqueous 
vapor around us.”* Such a speculation, which seeks for a 
Source of the nebulous matter itself, is perhaps a legitimate 
extension of the nebular hypothesis. 
Montreal, Feb. 14, 1880, 
Art. XLIV.—-On the Archean Rocks of the Wahsatch Mountains ; 
by ARcHIBALD Gxrxre, F.R.S., Director of the Geological 
Survey of Scotland, and Murchison Professor of Geology 
in the University of Edinburgh, 
Possible, however, that in these regions there may have been 
subsequent protrusions of granite and accompanying metamor- 
phism ; so that we ought not to decide that a mass is necessa- 
rily Archean merely because it consists of schists and granites. 
Yet I am not sure that this assumption has not to a certain 
Douglas, Jr., then President of the Society, and one of the Canadian Ex ition 
to observe the total solar eclipse of August 7, 1869. Therein, while discu: 
the Spectroscopic observations made during the eclipse, he refers to th To- 
fessor Young, who had suggested a comparison between certain lines in the > 
the solar corona, an y Winlock in that of the aurora 
borealis. With regard to these lines, Mr. Dougl 
therefore belong to some unknown eleme 
like the hypothetical ether, fills space?” 
tricity both “in the auroral light of our own heavens, and the co 
tay render this hypothetical gas luminous.” 
New Series, part 7, p. 82. 
* A Century's Progress, etc., cited above; also Chem. and Geol. Essays, pre- 
face to 2d Kd., p. xix. 
