58 
SPOLIA ZBYLANICA. 
total. The period of decay of the emanation appeared to point to 
the presence of a radioactive element closely resembling thorium 
X. Helium was yielded when the mineral was heated alone, 3*5 
c.c. per gram being obtained ; when fused with hydrogen potas¬ 
sium sulphate, it yielded 9*5 c c. per gram. 
In a subsequent letter ( Nature , April 14, p. 559) Professor 
Ramsay admitted that a considerable amount of thoria was present, 
in addition to the new elements, which may be identical with those 
recently discovered by Professor Baskerville. A partial analysis 
which was made in M. Curie’s laboratory gave 79 percent, oxides 
of rare earths (principally thoria) and 14 per cent, of uranium 
oxide. A rough preliminary analysis made by Professor Sir W. 
Ramsay is as follows : oxides like thorium oxide 76*4 ; uranium 
oxide 14“9; ferric oxide 6*1; lead, arsenic, &c., 20; insoluble 
(not Si 0 2 ) 0*7. At present the constitution of the new mineral 
and so also its commercial value cannot be regarded as definitely es¬ 
tablished ; we must await thh completion of further work in London. 
With regard to the analyses made at the Imperial Institute I 
may say that I have not observed any trace of zircon occurring as 
an impurity in the mineral, and do not think the Zr0 2 found can 
be due to the presence of inclusions of zircon, but rather that the 
zirconia enters into its composition. On the other hand, many crys¬ 
tals have a slight amount of limonite attached to the surface, and 
even if these be carefully excluded there are others containing 
small cavities lined with limonite which may in part account for the 
variations in specific gravity observed, so that a small percentage 
of iron oxide in the analyses may be regarded as an impurity. 
The properties of the mineral not already quoted are referred 
to below :—Colour black, streak greenish gray. Hardness, 5*5-6. 
Crystallizes in the cubic system, crystals rarely exceed 7 mm. 
along a cube edge. Some crystals consisting of two interpenetrating 
individuals appear to be twins, but this has not been as yet con¬ 
firmed by measurements. Fracture uneven, tending to conchoidal. 
Brittle. Lustre resinous to submetailic. Infusible. Dissolves 
readily in salt of phosphorus bead, vigorously giving off bubbles, 
doubtless of helium ; the bead in 0. F. is yellow when hot, green 
when cold, being the reaction for uranium. In borax bead yellow 
hot, pale greenish-yellow cold. Insoluble in acids. 
Some account of the localities and mode of occurrence may be 
given next. The mineral occurs in greatest abundance in loose 
waterworn crystals in the bed of the Kuda Pandi-oya, a tiny stream 
near Kondrugala, Bambarabotuwa, Sabaragamuwa, where it often 
forms the bulk of the heavy residue (“Nambu”) remaining in the 
gemming basket after washing. It collects also in hollows and 
