262 C. H. SMYTH, JR.—WEATHERING OF ALNOITE. 
organic matter. So far as possible, the latter was removed before pro- 
ceeding with the analysis. 
Resuutts or ANALYSES 
I II. III. LV Ne VI VIL. 
1 oy ~ 1 o js A a 
3 aS) “oS z ge a3 
3 sa So = rf ¢ z 
2 ov ay = ao 5) eo 
. a aS md. 5 ors Ov 
ay z ag tos ee oo oe 
8 Fs 5= ae | ©S | sec ae 
a is mash | BSS one aad as 
re +S ges 4 1O Sa ®) (Ele ow 
g é SeS| | SS | 2 Seo u| f= 
= fe cs Ss & a? 
He sae a ea 35.25 33.10 35.51 33.40 9.69 72.69 Pil? 
TOA Mepay) 2.90 QT 2.93 
ALO, 6.10 7.88 6.14 795} OED | HO.CD tap 
ISO ocoodos 8.53 16.71 8.59 16.86 | 2 
JMO. se eaiee 5.60 | 1,48 5.64 aor 0:55)" 96-30 | 3.00 
NCOP meee 20.40 13.42 20.505 13.54 10.08 51.03 | 48.97 
CaOze eee 7.40 (B) 21) 7.46 5.30 Bek) 54.90 45.10 
KG Oates: ».88 0.29 2.90 0.29 2.68 W033 92.27 
ING OR eae 0.70 0.23 0.71 0.23 0.53 23.03 74.97 
Ignition......| 10.15 17,85 10.23 18.01 0.00 100.00 0.00 
Total....| 99.26 99.11 100.00 100.00 26.89 
Discussion or ReEsuLTS or ANALYSES 
A comparison of the results of the analyses of the two rocks, as they 
stand in columns I and II, brings out some points of interest. The fig- 
ures for the weathered rock show a decrease in the percentage of all con- 
stituents aside from titanic oxide, alumina, iron oxide, and volatile matter. 
In the case of the latter, the figures do not indicate the true amount of 
change, for a separate examination shows the presence of nearly three 
per cent of CO, in the fresh rock, while there is not a trace of it in the 
weathered material. The latter, however, has about one per cent of or- 
eanic matter to be taken into account; so it is evident that weathering 
has been attended by hydration, which has more than doubled the amount 
of water. At the same time, much of the iron has changed from the 
ferrous to the ferric condition, as would be inferred from the decidea 
change of colorin the rock. It is possible that the percentage of ferrous 
iron in the weathered material is less than stated in column II, as the 
organic matter present would tend to make the results high for this 
constituent. 
