82 Improvements in Physical Science [Jane 
SUCataidc udigur Satie s ct os 6 CRORES 
pd oR a Ramen | 
WORIEG Cr WOH wt ka ce cc cece. ee 
} i. EE Re ee 
MTD 6.6 4-5 oS 0' «wh bio 0 = BUY 
Oxide of cerium .,........ 3°40 
Oxide of manganese........ 1°30 
WEY . scene nncunugans Jy vbr 
99°53 
Berzelius considers it as composed of 
True gadolinite............+. 83°67 
Bisilteate of lime .......0.4« 7°24 
Silicate of glucina ........ 2°90 
Silicate of. cerium «oo: sie, 4°38 
Silicate of manganese ...... 1°83 
100°00 
II, GEOGNOSY. 
This historical sketch has already extended to such a length, that 
I find it impossible to enter into the details which this fashionable 
and prolific branch of mineralogy would require. I shall, therefore, 
leave out for the present every thing that is contained in the third 
volume of the Transactions of the Geological Society, as I intend 
to give an analysis of that volume in a subsequent number of the 
Annals. A very small number of topics, therefore, will be touched 
upon here. 
1. Mineralogical Surveys:—It is scarcely necessary to observe, 
that all real progress in geognosy depends upon an accurate know- 
ledge of the structure of the earth. While idle speculations about 
the formation of the earth lead to nothing better than wrangling 
and confusion, every new fact respecting the relative position of 
rocks, every accurate description of a district, adds somewhat to 
our former knowledge, and: contributes towards the completion of 
the science. Geognosy will be complete only when we are accu- 
rately acquainted with the structure of the whole surface of the 
plobe, and when we understand completely the laws which regalate 
the changes which it is slowly undergoing. Nothing, ‘therefore, is: 
of more importance than accurate mineralogical surveys of every 
county of Great Britain, provided these surveys be conducted by 
men adequate to the undertaking.. ‘Phe plan sketched by Professor 
Jameson, and published in. the Annals, vii. 102, will serve as a 
very good model of what these surveys ought to be, while his mine- 
ralogical survey of Dumfrieshire will show how much can be accom- 
plished by one man within a moderate time. 
2. New Arrangement of Rocks.—In the Annals, vii. 478; T have 
given the formations in the Riesengebirge as determined by the 
celebrated German geologist Raumer. They are as follows :— 
1 
