86 Geographical Notices. 
eparation of magnesia from the alkalies in this way may — 
: therefore be considered as an accomplished fact, and I venture to 
think that this mode possesses points of convenience and ele- 
ments of accuracy fenders ering it preferable to any of those now in 
use. For qualitative analysis, and particularly for those cases in 
which it is desirable to combine a qualitative and a quantitative 
analysis in the same operation, it is particularly convenient. To 
mineral analysis also, it seems to me to be especially applicable. 
se and experience will of course increase its reliability an 
precision, and another nee iets will be presented on the 
subject. In conclusion I may remark that similar methods 
promise to be applicable in numerous other cases in which 
metallic oxyds are to be separated from the alkalies, at least 
when these oxyds or their carbonates are insoluble in alkaline 
carbonates, and their nitrates decomposable by heat, or the vapor 
of carbonate of ammonia. Such bases are lime, baryta, strontia, 
Soma yttria, thoria, and the oxyds of iron, zinc, cadmium 
r(?), cobalt, ‘iakel. lead, cerrum and bismuth (?). 
hen a comprehensive investigation in ¥hsich IT am now 
engaged, having for its object to ascertain precisely the action of 
heat upon all the metallic nitrates, shall have been brought to an 
ed es Pa _ a to pronounce more definitely upon some 
pam 
Art. XUI.— Geographical Notices—No. IL. 
OLD OCEAN ROUTES BETWEEN ENGLAND AND NortH AMER- 
1cA.—D. J. G. Kohl, whose historical investigations in respect to 
the progress of discovery on the coast of the United States have 
n for some time in progress for the archives of the Coast 
Survey, has lately ta publishing in the National Intelligencer 
(Washington, April 13 and ee ome May 1,) a series of articles 
on the old ocean routes between Europe and America. The 
prt ie presents many difficnlties, but in the extended researches 
e by Dr. Kohl, much that is of value has been collec 
We append a brief statement of the routes which he discusses. 
Tn respect to each, particular information is given, which illus- 
iagd ue Le ea ‘of knowledge in respect to the oceanic win 
