70 NORTHWESTERN BOUNDARY OF UNITED STATES. [bull. 174. 
Reconnoissances for developing the topography along and adjacent 
to the boundary line, and for locating routes of communication. 
These reconnoissances have extended over an area of about six thousand 
square miles. 
A full set of magnetic observations were made at one station. And 
throughout the work, all the necessary observations for time, azimuth, 
micrometer value, and instrumental corrections were carefully made. 
The two astronomical parties and the reconnoissance party were 
furnished with sets of meteorological instruments. Full and detailed 
registers have been kept at the different stations, and, as far as pos- 
sible, simultaneous readings of the barometer have been taken, while 
the parties were moving from station to station; which, with the cor- 
responding observations at camp Simiahmoo and the fixed stations, 
will enable us to give very exact profiles of the country traversed. 
The geological reconnoissance has been extended over the field of 
operations, and valuable collections made of botanical and natural 
history specimens. 
The forty-ninth parallel, as far as determined during the present 
season, traverses a mountainous country, and, excepting a few locali- 
ties, the entire region is eminently unfit for occupation or settlement. 
The mountains are rugged and precipitous, and attain great elevations; 
the ridges and peaks of the Cascade mountains being covered with 
perpetual snow. Glaciers were discovered; and during the months of 
June and July snow to the depth of two feet was encountered on our 
very route of travel. A heavy growth of pines and fir abounds 
throughout the entire line from the Gulf of Georgia, with the excep- 
tion of short intervals in the valleys of the Similkameen, Okinakane, 
and Nehoialpitkwu. 
Under the forty-ninth parallel the Cascade mountains have a 
breadth of about two degrees in longitude, and as the general trend 
of these mountains is at right angles to the line of our work, we were 
necessarily forced into crossing the ridges with our routes of commu- 
nication, involving much labor in cutting, grading, and bridging to 
make these routes practicable for even pack-mule transportation. 
The water courses are numerous and rapid, rendering the fords fre- 
quent and dangerous. A slight rise in these streams makes them 
impassable. Notwithstanding the difficulties of the country and the 
precarious mode of transporting the instruments, I am happy to report 
that we have got thus far through the season's work without any 
damage to our astronomical instruments. I regret, however, that we 
have been less fortunate with the magnetic instruments. The mule 
carrying these missed his footing and roiled down a precipitous bank. 
The magnetic theodolite will have to be replaced, and the other instru- 
ments will require repairing. I also have to report the breakage of 
our barometer. We were, however, able soon to replace this instru- 
ment from the lake depot. 
