INTRODUCTION. 



In submitting the following report of a reconnoissance of the 

 country bordering upon upper Red river, it is proper to state 

 that, previous to our departure upon the expedition, we were 

 unable to procure all the instruments adapted to the perform- 

 ance of such services as were required of us. We succeeded 

 in obtaining a sextant, a mountain barometer, an aneroid ba- 

 rometer, an odometer, a prismatic compass, and two Fahren- 

 heit thermometers; but could not procure a chronometer, 

 and, in consequence, were under the necessity of making our 

 observations with a pocket lever watch. 



The latitudes given are the results of from twelve to fifteen 

 observations of Polaris for the determination of each position. 

 The longitudes were determined by a series of observations 

 upon lunar distances, and are believed to be as accurate as 

 the imperfect character of our instruments would admit. 



The positions thus deduced have been corrected by frequent 

 and careful observations of courses and distances with the 

 compass and odometer, a record of which will be found in 

 the appendix. 



The astronomical observations were made by Captain 

 George B. McClellan, of the engineer corps, who, in addition 

 to the duties properly pertaining to his department, performed 

 those of quartermaster and commissary to the command. An 

 interesting collection of reptiles and other specimens, in alco- 

 hol, was also made under his superintendence, and put into 

 the hands of Professors Baird and Girard, of the Smithsonian 

 Institution, whose reports will be found in the appendix. For 

 these and many other important services, as well as for his 

 prompt and efficient co-operation in whatever was necessary 

 for the successful accomplishment of the design of the expe- 

 dition, I take this opportunity of tendering my warmest ac- 

 knowledgment. 



