300 J. Croll—Arctie Interglacial Periods. 
that there may be accumulations going on in the great oceans 
which we can no more see than we can the matters in solution. 
It is only because the mineral matters get concentrated in the 
sea water that they are forced upon our notice. They slowly 
concentrate until a balance is attained and they are removed 
from the sea water at the same rate that they are poured into 
at. 
Art. XLI.—On Aretic Interglacial Periods; by JAMES 
Crout, LL.D., F.R.S.t 
worse than they are at the present day. Greenland and the 
r. 
finest quality of salt by precipitating the slight proporti ddy impurities 
which the cold brine holds in jecaten by reat ~s eae , ‘ 
8 stion he carried out a series of experiments to determine the proportion 
of mud so removed. He found that i ounted to 1,556 tons of 
e =i g at the brine, purified and unpurified together in clean 
bottles, the difference betwi is 2 faint as me distinguishable. 
Tt of cou e color of the manufactured salt to a much greater extent 
both by the higher proportion the impurities bear to the salt and the whiteness 
of the salt. 
+ Phil. Mag., Jan., 1885. Communicated by the author. 
} Phil. Mag., May, 1884, p. 375; this Journal, June, 1884. 
