342 h ores try Quarterly. 



nected as far as possible in the field. They are based, not upon 

 barometer readings alone but, upon differences' in elevation deter- 

 mined by the barometer and checked by judgment and by angle 

 and distance. In other words this map is completed in the field, 

 and is dependent to a certain extent upon the judgment of the 

 topographer. Barometer and time readings are recorded upon 

 the field map at regular intervals as in the first case, but are dis- 

 regarded until the map is turned in for final adjustment. 



The important difference between these two methods is, that 

 in the first case form lines are not connected in the field while 

 in the second case form lines are connected in the field. 



It is for the purpose of discussing the relative merits of these 

 methods' that this paper is written. 



The barometer and a reasonable ability to pace constitute the 

 new topographer's chief assets, and perhaps because of the rela- 

 tive accuracy of the barometer, he is inclined to place unlimited 

 confidence in it. 



Considering now the method first described : — the topographer 

 starts from a control stake of known elevation and when the 

 barometer shows a change equal to the contour interval to be 

 used he unquestioningly indicates it by a line drawn across the 

 strip, showing the general direction of a contour at that point. 

 Other form lines, at irregular intervals, are drawn to indicate 

 minor changes in slope. He proceeds along the compass course 

 concentrating his attention upon the mechanical factors, his pacing 

 and the barometer. Important topographic features will be noted 

 superficially, but the business of properly indicating barometer 

 form lines on the strip occupies his mind. He misses the general 

 scheme of things entirely. 



Succeeding strips will be done in the same manner. Each 

 strip is a unit in itself, since no individual contour, and therefore 

 no particular land form of one strip is actually connected with 

 the complementary elements of the same land form on adjoining 

 strips. It is seldom that an important topographic feature is 

 complete in a single strip, and if the portion on each strip is 

 sketched as a detached fragment the feature as a whole is lost. 



No matter how careful the topographer may be, work done in 

 this manner will become mechanical and the form lines across 

 the strip will be simply a graphic representation of the barometer 

 readings taken. 



