[ 237 J 4 



As the views of ihe Secretary have been fully explained to you in the frequent conversations 

 you have had with hitn on the subject; and as the utmost confidence is reposed in your abilities 

 and industry, further instructions are considered unnecessary. 



****** 



Mr. Fremont will be assigned to you as an assistant. 



A copy of your map of the sources of the Mississippi and adjacent regions will be furnished 

 to you ; and .'-hould ihe government, in the end, publish the results which you have collected, 

 and are about colleciins:, in the form of a map, which is contemplated at present, proper credit 

 will be given to your labors, and you will be allowed the use of the plates, free of charge, for 

 the work you have in contemplation, of the Physical History of the Valley of the Mississippi, 



Very respectfully, &c., 



J. J. ABERT, 

 Lieutenant Colonel Topographical Engineers, 



On my return from this expedition, I set about, with the assistance of 

 Lieutenant Fremont and that of Lieutenant Scammond, (of the corps of 

 topographical engineers,) constructing the map ; the skeleton of which, 

 liaving been examined by many members of Congress, and its general plan 

 approved of, the Senate of the United States ordered it to be published when 

 finished, under the direction of the Topographical Bureau. 



I feel much indebted to Colonel Abert, now chief of the corps of topo- 

 graphical engineers, for the assiduous attention he has paid to the accu- 

 rate representation by the engraver of the geographical delineations of the 

 map, such as they now appear, and which this report is intended more- 

 fully to explain. 



The plan which 1 have adopted for the textual explanation of the map,, 

 is the following : 



\. To give a succinct account of the physical geography of the country 

 embraced within the limits of the map, including a narrative of the move- 

 ments of the expedition under my command, during the years of 1838 and 

 1839 ; and also an account of my visit to the sources of the Mississippi in 

 1836. 



2. An abstract of the principles and methods by which I have been 

 governed in making my observations, both for astronomical and physical 

 geography. 



These two subjects naturally divide the report into two parts ; and i 

 have added to it three appendices. 



Appendix A presents a tabular view of the geographical positions which 

 have guided me in the construction of the map. 



Appendix B is a catalogue of plants, for which 1 am indebted to that 

 eminent botanist. Dr. James Torrey, to whom I was proud of an oppor- 

 tunity — brought about by the liberal and disinterested intercourse whicit 

 characterizes American savatis, but perhaps more especially the gentleman 

 whom I have now the honor to name — of submitting my collection. The 

 catalogue has been arranged in accordance with the system adopted in the 

 publication of the American Flora, by Drs. Torrey and Grey. 



