Correspondence. 57 
WHITNEY, F. L. 
The new artesian water supply at Ithaca, New York. (Wat. 
Sup. Irr. Pap., No. 110, pp. 55-64, 1905.) 
WILLCOX, O. W. 
The so-called Alkali Spots of the Younger Drift-sheets. (Jour. 
Geol., vol. 35, p. 266, May, 1905.) 
WINCHELL, N. H. 
Deep wells as a source of water supply for Minneapolis. (Am. 
Geol., vol. 35, p. 266, May, 7905.) 
WOODBRIDGE, DWIGHT E. 
The Mesabi Iron Ore Range, xi. (Eng. Min. Jour., vol. 79, p. 
892, May 11, 1905.) 
WOODMAN, J. E. 
Distribution of Bedded Leads in relation to mining policy. 
(Proc. & Trans. N. S. Inst. Science, vol. 11, pp. 163-178, Mar., 1905.) 
WOODMAN, J. E. 
Geology of Moose River gold district, Halifax County, Nova 
Scotia. (Proc. Trans. N. S. Inst. Sci., vol. 11, pp. 18-82, 1904.) 
WRIGHT F. E. (and C. W. WRIGHT). 
Economical developments in southeastern Alaska. (Bull. U. S. 
G. S., No. 259, pp. 47-68.) 
WRIGHT, C. W. (See WRIGHT, F. E.) 
CORRESPONDENCE. 
Estimation of the Silica in the Bedford Limestone — The 
specimen used in this work was obtained from a quarry near Bed- 
ford, Indiana, and it is known locally as the Bedford limestone. It 
is a light-colored rock, fine grained in texture, and is widely used 
and favorably regarded as a building material. 
The amount of residue insoluble in hydrochloric acid which 
proved to be mainly silica was determined by three different meth- 
ods as follows: 
Method 1. 
A grain of the fine powder was placed in a small beaker covered 
with a watch glass. Dilute hydrochloric acid was added and the 
contents of the beaker gently heated to boiling. After standing 
a short time, the undissolved portion was filtered off and the 
weight determined. 
Method 2. 
A grain of the powder was placed in a porcelain evaporaing 
