120 A MANUAL FOR NORTHERN WOODSMEN 



3. After the boundaries are surveyed and the primary 

 point in elevation is fixed, a topographic survey and timber 

 estimate might be made together by means of the strip 

 system of survey described on page 188. For the topo- 

 graphic work, a barometer would be carried in the party 



Same Tract 

 as Surveyed by 

 Strip System 



and the elevation of needed points read and noted or 

 plotted down in connection with the chainage by the note- 

 keeper. If the air pressure was not steady, it would be 

 necessary for the barometer man once in a while to leave 

 the party and go back to the base for correction. The 

 combination of barometer and barograph gives rise, in a 



