8  DICTIONARY    OF    ALTITUDES    IN    UNITED    STATES. 
MISSISSIPPI  RIVER  COMMISSION    (MISS.   RIVER   COM.). 
These  elevations  were  determined  by  lines  of  precise  leveling,  which 
extend  up  the  river  from  near  its  mouth  to  St.  Paul,  across  to  Lake 
Superior  at  Duluth,  and  to  Lake  Michigan  at  Chicago. 
MISSOURI    RIVER    COMMISSION    (MO.  RIVER  COM.) . 
These  elevations  were  determined  by  a  line  of  precise  leveling 
which  extends  up  the  river  from  its  mouth  to  the  three  forks  in 
Montana. 
MULLAN,  CAPT.  JOHN. 
Explorations  for  a  Wagon  Road  from  Walla  Walla  to  Fort  Benton, 
1862.     All  heights  were  determined  barometrically. 
NEW  JERSEY  GEOLOGICAL  SURVEY  (n.  J.  G.  S.). 
Elevations  given  under  this  head  were  determined  by  lines  of  accu- 
rate leveling  carried  on  in  connection  with  the  preparation  of  the  map 
of  the  State. 
NEW    YORK    STATE    SURVEY. 
These  altitudes,  consisting  mainly  of  the  heights  of  triangulation 
stations,  were  determined  by  refined  trigonometric  work. 
NORTHERN    TRANSCONTINENTAL    SURVEY   (n.  TRANS.   SURVEY). 
These  altitudes,  chiefly  from  barometric  work,  were  executed  by 
the  Northern  Pacific  Railway  Company. 
PACIFIC    RAILROAD    REPORTS   (P.  R.  R.  REPORTS). 
Under  this  authority  is  included  work  done  by  the  War  Depart- 
ment between  1850  and  1855,  for  the  purpose  of  finding  a  practicable 
railroad  route  from  the  Missouri  River  to  the  Pacific. 
All  the  work  is  barometric  and,  taken  as  a  whole,  is  poor,  owing 
mainly  to  the  fact  that  practically  there  were  no  barometric  base 
stations.  The  hypsometric  work  of  the  expedition  near  the  northern 
boundary,  under  Governor  Stevens,  was  particularly  bad.  These 
remarks  concerning  the  quality  of  the  work  apply  as  well  to  all  the 
earlier  expeditions  to  the  West,  owing  doubtless  to  the  same  cause. 
PARRY,  PROF.  C.  C. 
These  elevations  were  determined  barometrically. 
POWELL,  MAJ.  J.  W. 
To  this  authority  is  credited  the  hypsometric  work  of  the  United 
States  Geological  Survey  of  the  Rocky  Mountain  Region.  The 
determinations  were  made  by  the  use  of  the  barometer  or  by  vertical 
angles  depending  upon  bases  determined  by  the  barometer. 
