WILSON ON GEOGRAPHICAL WOEK OF THE SURVEY. 729 



topographer working in concert would make a general plan for the 

 summer campaign, and equip themselves with all the necessary instru- 

 ments and supplies. 



On reaching the district, they would select the first commanding 

 point and ascend it ; on reaching the summit, the topographer sets up 

 his theodolite, while the assistant hangs up the barometer. 



The topographer proceeds to make a carefal drainage sketch, on which 

 he would indicate all features of note, while the assistant makes a care- 

 ful profile sketch of the entire surrounding country on a large scale. 

 Upon these sketches would be marked, by numbers or names, all the 

 points to be sighted, or in some cases the actual bearings are placed 

 upon the sketches. 



After this was done, the bearings of all peaks, points, ends of spurs, 

 junctions of streams, in fact every recognizable feature of the surround- 

 ing country, would be sighted, and the angles, both horizontal and ver- 

 tical, recorded in a book, with their numbers or names appended. 



From this first station would be selected a number of points occupy- 

 ing commanding positions, as points to be occupied as stations in future, 

 and so on from each station there would be constantly selected points 

 in advance, on which stations were to be made. 



After finishing the work on the peak, the party would proceed to the 

 next, and there repeat the sketches and angles, taking great care to 

 check every jjrevious sight possible, and taking all the new points that 

 came within range. 



Thus from day to day the country is sketched from every possible 

 view, and the points are each time sighted, giving many checks to the 

 location of all the more prominent features of the country. 



The mountainous regions of the country west of the Mississippi Eiver 

 are generally very favorable to this kind of work. Nearly all the moun- 

 tain-peaks, especially near their summits, are destitute of timber, while 

 the valleys are uniformly so, the timber in nearly all cases growing on 

 the slopes of the mountains. 



Therefore, from the mountain-peaks the drainage of the country is 

 clearly visible and sharply defined. Thus the topographer is often able 

 to trace the meanderings of a stream for many miles, as it recedes over 

 the distant plains or valleys. 



To do this class of topographical work successfully, it requires a man 

 with a natural faculty for the recollection and recognition of objects 

 which he has seen from different positions, especially in a high, rough, 

 mountain country, where so many points are visible from one peak, 

 and they undergo great changes in appearance as seen from difierent 

 positions. 



Yet this faculty may be cultivated to a wonderful degree when the 

 person is very careful and studies the relative positions of things, also 

 the individual forms and characteristics of mountain structure. It is 

 very much the same faculty that is required in recognizing faces, for each 



