COMPOSITION OF THE RED CLAY 785 
analyses. The magnitude of these variations, however, was deter- 
mined, and appears in the figures given below. The final data are 
as follows: 
. General analysis, by Mr. George Steiger. 
. Portion soluble in cold water, by Mr. George Steiger. 
. Special determinations, by Dr. W. F. Hillebrand. 
. Special determinations, on material concentrated from 150 grammes of clay, 
by Dr. E. C. Sullivan. 
Yow pP 
These last determinations were checked by blank experiments 
upon equal quantities of the reagents employed in the research. 
TABLE I 
A. B. C. D. 
SNOhrodosesooger 45-32 none Ba@ reir 0.16 Cu@*,. .;.01.02 
ANAOBo soe eee oued 13.20 none GHORs Goc@sonert Wh IANO Ross 0.007 
Ime Oedanewocnen 20 none WHOPAGaoe Choris II) AlOneses 0.004 
HE OPiS tase cs 0.70 none MoO3....trace As203....0.0007 
IMA OS Se nema Seer B05 O.2T 
CaOQvesscsedeeas 6.82 0.19 
Nas ON i sexes ss 3.63 avon 
eG Oi Mint cevete eseqsects 2.43 
Ea @Oyat TO62.. : « 3.28 
H.20O above 106° 5-93 
ADO Pye cheam onene 0.82 
CO pias ase. 3.91 
BHO esdoousm aac. 0.25 ee 
SOsisoobec.qposes 0.48 0.39 
CU er ren cenl stebersacre 27 2473 
AE ralaye porte ersioes none mes 
Cr203. 0.01 
NiO, CoO 0.032 
MnO2. TOL 
Ba Oy. Giccio.cls ses On 17 
SrO myer ees 0.046 
N15 OP Nore cia none 
Wis OR tetas 0.023 
IOI .141 Rone 
Less O=Cl...... 0.62 0.62 
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 recognized. The absence of 
