T. S. Hunt—Chemical Relations of the Atmosphere. 349 
the last of the season, as I surveyed from the north the 
road through Red Rock Pass, after noting the remarkable topo- 
graphical features of Marsh Creek, and keeping a close run of 
the profile as given by the aneroid, I was delighted at Red 
ock to see unmistakable evidences of the ancient outlet of 
Great Salt Lake. .. . . Thus you may have the gratification of 
knowing of an independent and entirely unbiased verification 
of yourdetermination of this point; and it is nowhere else in 
the limits I have mentioned.” 
Arr. XLIIL—7he Chemical and Geological Relations of the At- 
mosphere ;* by T, Sterry Hunt, LL.D., F.RS. 
QUESTIONS concerning the condition of the terrestrial atmos- 
phere in former periods of the earth’s history, and its geological 
relations, have occupied the attention of naturalists, physicists 
and chemists. Bronguiart long since suggested that the abundant 
vegetation of the Coal-period indicated the existence of a large 
pe ornion of carbonic acid in the air at that time. elmen, 
Owever, appears to have been the first to clearly understand 
the great geological significance of the atmosphere, and in his 
tA summary of the views presented in this memoir was given at Dublin, in 
August, 1878, before the British Association for the Advancement of Science. 
An abstract thereof appeared in the Proceedings, and will be found in Nature for 
August 29, 1878 (vol. xviii, p. 475.) ‘The principal conclusions of the memoir are 
also embodied in a communication made by the author to the French Academy of 
Sciences, and published in the Comptes Rendus of September 23, 1878 (vol. 
lxxxvii, page 452.) They will also be found set forth in the preface to a second 
99m of the writer’s Chemical and Geological Essays (pages ix-xix) published 
m the spring of the same year. 
t 4th’ Series, vols. vii si xiii, These memoirs will also be found in the 
Receuil des Tray. Scient. de M. Ebelmen; Paris, 1855, vol. ii, pp. 1-79. 
