118 Forest Club Annual 



of the camp was computed to be 1853 feet above sea level. 

 Each of these thirteen sets of readings, was given the same 

 weight in averaging, so that the accepted elevation of the camp 

 was eleven-thirteenths of 1893 plus two-thirteenths of 1853 or 

 1887 feet above sea level. 



The determination of the elevation of a side camp sent out 

 from a main reconnaissance camp was but slightly different. 

 When a party started out for a trip extending over a week or 

 more they set their aneroid . at the elevation of the main camp 

 before they left. Upon their arrival at the site of their temporary 

 or side camp, the aneroid was read and recorded and either this 

 figure or an arbitrary figure was assumed as the elevation of the 

 site. When the party left this site to return to the main camp the 

 aneroid was set at this assumed elevation and was read upon their 

 arrival at the main camp. These two sets of figures were used 

 to determine the true elevation of the side camp. In working 

 from the temporary camp the aneroid was set at this assumed 

 elevation every morning and read upon returning in the evening. 

 All readings taken during the day were referred to this assumed 

 elevation and later corrected in the main camp where a constant 

 figure was allowed for the difference between the assumed and 

 true elevation in addition to the atmospheric correction. 



Before the field sketches were copied on the final sheet 

 they were corrected for elevation. The aneroid readings shown 

 on the field map were accompanied by the exact time at which 

 they were taken. In making the corrections on the sketch the 

 readings were crossed out and the true elevations placed above 

 them. The true elevation was obtained by adding the correction 

 for the hour to the aneroid reading, or subtracting it, depending 

 upon whether it was a positive or a negative correction. 



The aneroid barometer is especially suitable for use in 

 a mountainous country with a very rugged topography. Ele- 

 vations can be taken with the aneroid in country which is so 

 rough that other instruments cannot be use" 1 , for it can be 

 carried in the pocket. The elevation of any cliff or peak which 

 can be scaled may be obtained. The aneroid is desirable to use 

 in a country such as the west slope of the Cascade Mountains, 

 which has a dense growth of underbrush and reproduction. In 

 such a locality the use of the level or stadia is impossible without 

 an extra man to cut brush ahead of the instrument man. Be- 

 cause of the small amount of time necessary to read the aneroid 

 and sketch in the contours on the field map, it is a very desirable 

 instrument for taking fairly accurate elevations, especially if 

 it is done in connection with other work such as reconnaissance. 

 When carefully used the aneroid barometer gives fairly accurate 

 elevations. 



