1817.] during the Year 1816. 95 
Berzelius considers it as composed as follows :— 
Oxide of tantalum .. 67°586 
’ Oxide of manganese.. 5°902 : 
, Tantalite Oxide of iron...... 7560 ( 92°552 
~ Lime eeoeeereverece 1°504 
WVolivmm sce seer peek wi. Sls pes SOO 
Tin-stone enerrereeeeerr oe eer eerereeseeeeas 8°758 
100°000 
Tantalite, therefore, is composed of 
Oxide-of tantalum’... 0622. cc 000s 81°S72 
SMEG NOD... wp vs ilagh cupswanesee, DLS 
Oxide of manganese ........0.0002 7°124 
EAE” ows a's as co och widicejaw ls dale ta O2b 
100°000 
Its symbol, therefore, is Ca Ta + 3 Mn Ta +4 Fe Ta, or 
(Ca Ta + Fe Ta) + 3 (Mn Ta + Fe Ta). 
If. Examination of the Composition of Gadolinite, by J. Ber- 
zelius. This is a curious and elaborate analysis. He shows that 
yttria had never been completely freed from cerium ; and that when 
obtained in a state of purity, it is white, and forms colourless salts 
with acids. Sulphate of yttria is composed of 100 acid + 100 
yttria. Hence yttria contains 20 per cent. of oxygen. So that if 
we consider it as a protoxide, the weight of an atom of yttrium will 
be 4; but if yttria be a deutoxide, the weight of an atom of yttrium 
will be 8, 
Gadolinite from Finbo was composed of 
Silica esteeeeweeveeoeeeeeeeeeeee ee eae 25°80 
AMER OL ir sigh eek: Seas caunicandlesd. coAOe 
Protoxide of cerium.........-.+. ... 16°69 
Peoboside Of i000 ois vis cai o bows ss LOGE 
Water ii scsose.s eae valde oy LyOEO 
98°35 
Gadolinite from Broddbo, of 
MN Wie haba viacals site ei wal eee n claaninde LG 
oy) a Oe ae PPO a hor oes 45°93 
Protoxide of cerium ................ 16°90 
Protoxide of iron .......... srevestpieta’st LL Rew 
WO eee) FIRE de Pie db an hike cat 
98°93 
Hence its symbol, according to Berzelius, is f*S + ce® S + 
8 YS. 
II. Analysis of the Fluosilicates hitherto discovered, or of the 
Minerals arranged under the Species Topaz. By J. Berzelius.— 
The minerals analyzed by Berzelius were the Brazilian topaz, the 
Saxon topaz, and the pyrophysalite. The results were as follows :— 
