162 A. Guyot on the Appalachian Mountain System. 
Institution. They have been kindly left at my disposal by the 
| compa 
not only before and after each pire but also during the cone 
of each, whenever there has been an opportunity. The 
co nding observations have always been made with one OF 
the other of the barometers thus compared, and their relative 
corrections, resulting from the equations thus established, ha 
ae 
