SOIL CHEMISTRY: E. W. HILGARD 
the material pointedly from that group, even apart from the exception- 
ally high absorptive power for water. I believe that what has been 
shown is sufficient to characterize a new kind of clay with a predominant 
magnesium instead of aluminum base, for which I suggest the name of 
Lucianite, from the locaHty where it was found. A better name, Auxite, 
referring to the exceptional increase in bulk, is too similar in sound to 
Augite to be desirable. 
Wishing to obtain, if possible, additional material from the Mexican 
locaHty, I wrote to Don Jose G. Aguilera, the Director of the Institute 
Geologico de Mexico, at the City of Mexico, transmitting also a blue- 
print map on which Dr. Shaw had marked the several localities from 
which he took samples. Dr. Aguilera very promptly and courteously 
responded to the request, despite the disturbed condition of the country 
(in 1912). Dr. Aguilera also sent statements of the analyses of clay ma- 
terials from the foundations of the Legislative Palace, when building in 
1904. These also show a large predominance of magnesia in the sub- 
strata of Mexico City. 
The samples received, all from low 'alkah spots' in the Hacienda, 
resembled in general aspect the material brought by Dr. Shaw, but con- 
tained more coarse materials, among which talcose schist and black 
eruptive rock were readily discernable. The fine portions all showed 
exceptionally high expansion when wetted, one going as high as 12 
times the bulk of the raw, dry mass. It was then attempted to obtain 
from this sample by sedimentation a clay of higher absorptive power. 
But the highest result so obtained was only 16 times the original bulk. 
QuaHtative tests of this material showed again a large proportion of 
caltium and magnesium carbonates, with only small amounts of alumina 
and ferric oxide. The microscopic characters were the same as before 
noted in the original material, and there was the same easy decomposi- 
tion of the silicate present with even weak acids, which stands in the 
way of obtaining a substance of definite and constant composition, free 
from earth carbonates. 
As regards the reclamation of these alkah spots it is obvious that it 
cannot be accomplished by liming, as a large amount of calcium carbo- 
nate is already present and yet does not prevent the collapse of the col- 
loidal ingredient in drying. The depressed spots probably become nearly 
level during the rainy season by the expansion of the colloidal ingredient. 
It seems as though acid treatment, instead of that with lime, were the 
only possible eft'ective agent. 
Circumstances have prevented a further prosecution of this investi- 
gation, which will be resumed whenever possible. Meanwhile it may be 
