42 SCIENTIFIC B 0 OES PUBLISBED BY 
Ernst’s Manual of Military En 
gineering. 
193 Wood Cuts and 3 Lithographed Plates. 12mo. Clotli. $5.00. 
A MANUAL OF PRACTICAL MILITARY ENGINEER 
ING. Prepared for the iise of the Cadets of the U. S. Military 
Academy, and for Engineer Troops. By Capt. 0. H. Erkst, 
Corps of Engineers, Instructor in Practical Miiitary Engi 
neering, U. S. Military Academy. 
Church’s Metallurgical Journey. 
24 Illustrations. 8vo. Cloth. $2.00. 
NOTES OF A METALLURGICAL JOURNEY IN 
EUROPE. By Johm A. Church, Engineer of Mines. 
Blake’s Precious Metals. 
8vo. Cloth. $2.00. 
REPORT UPON TUE PRECIOUS METALS: Being Statisti 
cal Notices of the principal Gold and Silver producing regions 
of the World. Eepresented at the Paris Universal Exposi 
tion. By William P. Blake, Commissioner from the State 
of California. 
Clevenger’s Surveying. 
Illustrated Pocket Form. Morocco Gilt. $2.50. 
A TREATISE ON THE METIIOD OF GOVERNMENT 
SURVEYING, as prescribed by the United States Congress. 
and Commissioner of the General Land Office. Witli com- 
plete Mathematical, Astronomical and Practical Instructions, 
for the use of the United States Surveyors in the Field, and 
Students vrho contemplate engaging in the business of Public 
Land Surveying. By S. R. Clevekger, U. S. Deputy Sur- 
veyor. 
“ The reputation of the author as a surveyor guarantees an exhaustive 
treatise on this subject.”—Dakota Register. 
“ Surveyors have long needed a text-book of this description.—The Press.