126 T. S. Hunt—Celestial Chemistry. 
having on various occasions within the past fourteen years, 
put forth and enlarged upon this conception without mention- 
ing Sir Benjamin Brodie, whose only publication on the subject, 
so far as I am aware, was his lecture of 1867, unknown to me 
until its reprint in 1880. 
It was at the grave of Priestley, in 1874, that I for the second 
time considered the doctrine of celestial dissociation, commenc- 
ing with an account of the hypothesis put forward by F. W. 
Clarke, of Cincinnati, in January, 1873,* to explain the grow- 
ing complexity which is observed when we compare the spectra 
of the white, yellow and red stars; in which he saw evidence of 
a progressive evolution of chemical species, by a stoichiogenic 
process, from more elemental forms of matter. I then r eferred 
to the further development of this view by Lockyer i in his com- 
munication to the French Academy of Sciences in November 
of the same year, wherein he connected the successive appear- 
ance in celestial bodies of chemical species of higher and higher 
vapor-densities with the speculations of Dumas and Pettenkofer 
as to the Sekai nature of the chemical Slaaenet I then 
conceive to be condensing into suns and planets, have hitherto 
shown evidences only of the presence of the first two of these 
elements, which, as is well-known, make up a large part of the 
- gaseous envelope of our planet, in the forms of air and aqueous 
vapor. With this, I connected the hypothesis that our atmos- 
phere and ocean are but portions of the universal medium 
which, in an attenuated form, fills the interstellary spaces; and 
further suggested as ‘‘a legitimate and plausible speculation,” 
that “these same nebule and their resulting worlds may be 
evolved by a process of chemical condensation from this univer- 
sal atmosphere, to which they would sustain a relation some- 
* Clarke, “ Evolution and the Spectroscope,” Popular Science Monthly, New 
York, vol. ii, p. 
+ Lockyer : Comptes Rendus, November 3, 1873. 
