42  SCIENTIFIC  B  0  OES  PUBLISBED  BY

Ernst’s  Manual  of  Military  Engineering. ­

193  Wood  Cuts  and  3  Lithographed  Plates.  12mo.  Clotli.  $5.00.
A  MANUAL  OF  PRACTICAL  MILITARY  ENGINEERING. ­
  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  Engineering, ­
  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  Statistical ­
  Notices  of  the  principal  Gold  and  Silver  producing  regions
of  the  World.  Eepresented  at  the  Paris  Universal  Exposition. ­
  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  complete
  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  Surveyor.

“  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.