38 REPORT. 



the result ; the preparation of the general map and its engraving ; the compilation of profiles 

 of all the routes recently explored and previously examined barometrically ; the preparation 

 of all the maps, profiles, and other drawings made in the office, comprising the duplication of 

 the originals received from the exploring parties; the preparation of reports upon those 

 routes and portions of routes and lines formerly explored, but not with a special view to the 

 railroad question. In addition to this, he has likewise largely aided me in making this 

 report. 



This laborious service has been executed by him with great intelligence, zeal, and energy. 

 Lieut. H. L. Abbot, topographical engineers, was assigned to duty in this office in October 

 last, and has most zealously aided Lieut. Warren in the compilation of the office profiles, 

 and assisted me in investigations connected with this report. 



I would especially call your attention to the admirable arrangement of the profiles which 

 have been compiled in the office, by Lieuts. Warren and Abbot, exhibiting so well all the in 

 formation upon, and the data and statistics of the routes, (as for as it is possible to compress 

 them into so small a space,) as to serve the purpose of a brief report. 



In making this examination I have had the advantage of frequent personal conferences with 

 the chiefs of the exploring parties, and with Dr. John Evans and W. P. Blake, esq., geologists. 

 I have also availed myself of the information contained in the memoranda upon various 

 practical points connected with the construction and working of railroads; prepared in the 

 office by Bvt. Capt. George B. McClellan, corps of engineers, as suggested by my letter to the 

 department of the 7th October last. 



Very respectfully, your obedient servant, 



A. A. HUMPHREYS, 



Captain Topographical Engineers. 

 Hon. JEFFERSON DAVIS, 



Secretary of War. 



