APPENDIX. 549 



coat, which some of you may have near the arm. The best mode of 

 observing a star in the artificial horizon, is to clamp your index and 

 wait its contact. Choose for time those that are east or west, and of 

 altitude about 30°. If you observe about the same hour every night, 

 you will find the computation more convenient. 



All your observations must be worked up as soon as possible after 

 they are taken. 



6th. Your route or travel must be kept by compass: this you will 

 find without difficulty in an open country, but through the woods it 

 will be better that each of your party be required to keep his reckon- 

 ing, by which you can correct your own. 



The longitude of Fort Vancouver is 122° 39' 34" W., and its lati- 

 tude is 45° 36' 53" N., from which you will take your departure. 



7th. To obtain the distance of remote objects, base-lines may be 

 measured on the plains. For this purpose the steppings of a horse 

 will give the best results, by first measuring his steps in one hundred 

 or five hundred feet, and at the ends observe the angles and bearings. 



8th. A tape-line is furnished you for getting the measurement of 

 trees, short bases, &c, and any remarkable object you may meet 

 with. Attend to the velocity of rivers by the distance that a chip 

 will pass in any given number of seconds by your watch, and the 

 ratio of a log-line may be adopted. 



9th. At all your encampments you will get readings of your baro- 

 meter, and the thermometer will be taken every six hours, and as 

 often also as any change of altitude or temperature may require. 



If by any accident your barometer should be broken on the heights, 

 try the temperature at which water boils. 



It is required of you to obtain the heights of all mountain ranges 

 and peaks, and the geographical position of those which have well- 

 defined peaks. 



I need not inform you that sketches from the tops of high hills, with 

 good bearings, will go far to illustrate the country through which you 

 pass : the delay of a day for this purpose will be amply repaid by the 

 information obtained. 



10th. It may be desirable for the scientific gentlemen to make 

 occasional short excursions from your direct route. You will in that 

 case afford all facilities in your power to prosecute their researches. 



11th. The information also expected from your party, will be names 

 of tribes, numbers, manners, customs, mode of living, habits, charac- 

 ter, disposition, and incidents that may occur to the party, as also the 



vol. v. 138 



