86 C, A. Goessmann on ihe Chemisiry of Brines, 
+ 
‘as 
: 
Hy 
affinity under both of these circumstances; the difference in the 
relative isis s of the various compounds depends on entirely 
different cause a 
The vartcciier conditions required to render such a change of — 
the brine possible, are, it can scarcely be denied, abundantly 
— particularly in consequence of the extensive exposure 
of sodium has been and is still 
performing a& most cay et ae part in the disintegration of a — 
pene’ number of rocks, by chemical and particularly by mechan | 
forces in consequence of its hygroscopic quality. % 
* Chlonid of sodium and sulphate a ao are almost every where 
associated ; they occur not only as more or less well defined ae 
posits of varying extent, but they nae originally have perva 
every sedimentary rock from the lowest Silurian to the latest ma- 
rine formation. Subsequently they have found access to many 
formations of a later date afd different origin by the ascent of 
ating waters. Most of these rocks contain, more or less 
abundantly, compounds of magnesia, particularly carbonates,* 
and have thus uninterruptedly yielded quantities of that sub- 
stance to solutions, wherever such powerful omnes 1a 
cies as change of temperature, access of vein ure and free cal- 
bonic acid have been at work; the destruction of these rocks is 
a mere matter of time. Many ‘sedimentary rocks may have been 
exposed to these influences temporarily, perhaps in a less indu- 
rated state, and consequently have presented conditions most — 
favorable for transformation and su subsequent extraction; circum: — 
stances which may sometimes account for the total or partial ab 
straction of eriphate of lime from a number of sedimentary _ 
rocks of marine origin.+ a1 
Belg ‘here, more on the duration than on the intensity of the 
action, I believe that the final results of reactions like those con- 
sidered in the foregoing discussion, must in common with 0 
causes, have exerted an important bearing on the composition of 
the marine waters, during the development of our present sur 
Pe va 
. 
__* Researches of Ebelman, confirmed by T. S. Hunt, have proved that magnesia 
and lime are first abstracted, by means of carbonic acid, rah th basaltic and sim- 
gives, in 1000 parts, NaCl 6:32 5622, N iL, CaCl 03158 cc 
