1906-7.] The Composition of the Red Clay. 169 
These last determinations were checked by blank experiments upon 
equal quantities of the reagents employed in the research. 
A. 
B. 
C. 
D. 
Si0 2 
. 45-32 
none 
BaO . -16 
CuO . -02 
A1 2 0 3 
. 13-26 
none 
Cr 2 0 3 . -Oil 
PbO . -007 
Fe 2 0 3 
. 7-20 
none 
V 2 0 3 . -035 
ZnO . -004 
FeO 
. -70 
none 
MoO s . trace 
As 2 0 3 . *0007 
MgO . 
, 3-05 
•21 
CaO 
. 6-82 
•19 
Na 2 0 . 
. 3-63 ) 
2-01 
K 2 0 
. 2-43 ) 
H 2 0 at 106° 
. 3-28 
H 2 0 above 106° 5'93 
Ti0 2 . 
. -82 
co 2 . 
. 3-91 
p 2 o 5 . 
. -25 
so 3 . 
. -48 
•39 
Cl . 
. 2-77 
2-73 
F . 
. none 
Cr 2 0 3 . 
. -oi 
NiO, CoO 
. -032 
Mn0 2 . 
. 1-01 
BaO 
. -17 
SrO 
. -046 
Li 9 0 
. none 
v 2 o 3 . 
. -023 
101-141 
5-53 
% 
Less 0 = Cl 
•62 
•62 
100-521 
4-91 
Zirconia and the rare earths were sought for by Dr Hillebrand, but not 
found. Titanium, chromium, vanadium, barium, strontium, nickel, copper, 
lead, zinc, arsenic, and molybdenum were not reported in the Challenger 
analyses. Their widespread distribution in the igneous rocks is, however, 
well recognised. The absence of lithium and fluorine is noteworthy. The 
unusually high proportion of manganese suggests the presence of disseminated 
or incipient manganese nodules, like that so admirably analysed by Gibson. # 
In his work several of the rarer elements were determined ; so that their 
existence in the oceanic sediments is no new discovery. The fact of their 
general distribution, however, remained to he proved. 
In order to establish the true composition of the clay substance, some 
deductions must be made from the analysis as it is now stated. Hygro- 
scopic water and soluble matter must be eliminated, and also the calcium 
carbonate which is represented by the C0 2 . The composition of the 
* Deep-Sea Deposits , pp. 422, 423. 
