288 APPENDIX. 



the objects of the Expedition, indefatigable in their inquiries and 

 observations, and never withholding their personal exertions. 

 Ardent in their pursuit after knowledge, with great attainments 

 in the departments of literature to which they have respectively 

 devoted themselves, and with powers which will enable them to 

 explore the whole field of science, I look forward with confi- 

 dence to the day when they will assume distinguished stations 

 among our scientific men, and powerfully aid in establishing the 

 literary fame of their country. 



Should any object of a similar character again require similar 

 talents, I earnestly recommend their employment. Whoever has 

 the pleasure of being associated with them, will find how easily 

 profound acquirements may be united with that urbanity of 

 manners, and those qualities of the heart, which attach to each 

 other those who have participated in the fatigues of a long and 

 interesting tour. 



Very respectfully, sir, 



I have the honor to be 



Your obedient servant, 



LEWIS CASS. 



Hon. John C. Calhoun, Secretcmj of War. 



2. TOPOGRAPHY AND ASTRONOMY. 



Topographical materials were collected by Capt. Douglass, U. 

 S. A.,for a map of the northwestern portions of the United States, 

 embracing the complete circumnavigation of the great lake basins, 

 and accurate delineations of the sources of the Mississippi, as low 

 down as the influx of the Eiver Wisconsin. Being provided with 

 instruments from the Military Academy of West Point, astrono- 

 mical observations were made at every practical point over the 

 vast panorama traversed by the Expedition. A line of some four 

 thousand miles of previously unexplored country was visited; 

 his notes and memoranda for a topographical memoir were full 

 and exact ; and they were left, I am informed, in a state of nearly 

 perfect elaboration, accompanied by illustrations, and many draw- 

 ings of scenery. Having written to his family recently, for the 

 astronomical observations, they were transmitted by his son in a 

 letter, of which the following is an extract : — 



