Allen.and Comstock—Bastniisite and Tysonite. 391 
By converting a known weight of the mixed oxides of the 
mineral into anhydrous normal sulphates, the joint atomic 
weight of the metals was found to be 140°2. If from the car- 
bonic acid obtained, an amount of the bases is calculated sufii- 
cient to form normal carbonate, the remainder of the bases 
calculated as metals and the fluorine estimated by difference, 
the mean becomes : 
Ratio. 
(Ce, La, Di)2O3 == 60:13 “153 
Ge,La, Di =21 155 
= 20°15 “458 
e900 “416 
100-00 
RO,: BR: CO.* Fl=1: 1911 322°72; 
corresponding to the formula 
R,Fl, + 2 R,(CO,), 
in which R=Ce, La and Di. If the atomic weight of R=140-2, 
as found in the present case, the formula requires :— 
(Ce, La, Di),0, = 49°94 
be La, Di comet 9 as 
This mineral corresponds to that from Sweden described by 
Hisinger* under the name of Basiskfluorcerium. It was later 
re-investigated by A. E. Nordenskiéld,+ who first ascertained 
Its correct composition and called it hamartite. Huot had, how- 
ever, previowal y-oalted the mineral basindsite, after the locality. 
Nordenskiéld’s analysis is given above for comparison. 
Associated with bastndsite occurs a mineral which proved to 
be an anhydrous normal fluoride of cerium, lanthanum and 
didymium, which we have examined with the following results : 
= 4°5-5. Specific gravity = 6°14, 6°12. 
Luster vitreous to resinous. Color pale wax yellow. Streak 
nearly white. B.B. blackens but does not fuse. In closed 
tube decrepitates, the color changes to a light pink, and shows 
slight traces of moisture. Insoluble in hydrochloric and nitric 
acids, but dissolves in concentrated sulphuric acid with evolu- 
tion of hydrofluoric acid. Qualitative examination showed only 
the presence of fluorine and the metals of the cerium group. 
Quantitative analysis gave the following results : 
M 
‘8 Eh ean. 0. 
Ce = 40°16 40°22 40°19 +284 50 
La, Di = 30°29 30°45 30°37 “220 
Fl (diff.) = 29°55 29°33 29°44 L547 
100-00 100-00 100-00 
* Cf. Ak. Stockh., 1838, p. 187. }+ (Ef. Ak. Stockh., 1868, p. 399. 
Birich’s atomic weight (141-2) for cerium was use for calculations. 
A known weight of the mixed oxides was converted into anhydrous normal 
sulphates, care being taken that the cerium should exist wholly as cerous sul- 
