J. W. Draper—Distribution, ete., in the Spectrum. 91 
XIL The conformability of the western range of limestone 
in Alford with the slates of the Taconic ridge still farther west 
has, in an early part of this memoir (p. 2), been made a basis 
for the conclusion—the ordinary one of geological writers on 
the subject—that the Taconic slates are older than the Stockbridge 
limestone. But it must be shown that the Taconic ridges are 
not the courses of synclinal folds, before this can be accepted 
as an established fact. 
_ ve may now turn to the region east of the Housatonic 
river, 
(To be continued.) 
ArT. XL— Researches in Actino-chemistry. MEMOIR SECOND. 
On the Distribution of Chemical Force in the Spectrum ; by 
Joun Winttam Draper, M.D., LLD., President of the Fac- 
ulties of Science and Medicine in the University of New York. 
[Continued from page 38.] ; 
2d.—Of the union of chlorine and hydrogen. 
a large jar filled with chlorine. This arrangement may be 
salt, that it could be used as a gas jar. The radiations of a 
lamp were caused to pass through it, so as to be submitted to 
the selective absorption of the mixture. They were then 
v 
Wo facts were now apparent, Ist, the mixture of chlorine 
and hydrogen in the absorption vessel began to unite under the 
Influence of the rays of the lamp. 2d, the rays which bad 
