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APPENDIX. 



When you take an azimuth, which ought to be daily, take it on 

 some well-defined object, and note carefully the bearing of it by the 

 prismatic compass. It is particularly desired to multiply these obser- 

 vations. 



Your route or courses must be kept by compass : this you will find 

 no diflSculty in doing in an open country; but through the woods it 

 will be better that all your party should be required to keep their 

 own reckoning, which you will use, together with your own, in the 

 same way as at sea. The longitude of Fort Nisqually for your 

 departure you may take as 122° 53' W., its latitude 47° 07' 30" N. 

 To serve you for more accurate measurement than mere guess, time 

 the paces of your horses, and the length of each pace will be your 

 scale. 



You will map or keep a diagram of your work on the pages of your 

 journal, taking the ruled lines as a convenient scale of miles, marking 

 thereon the mountains, hills, woods, rivers, brooks, and plains, within 

 your horizon. This will be more effectually done by ascending any 

 hill to take a bearing from. Every remarkable object you will desig- 

 nate by its native name ; if it has none, give it one of your own. 



A tape-line is furnished you to get any measurements with, such 

 as the width of rivers, &c. ; also find the velocity by the distance a 

 chip will pass in a given time. You will measure also any remark- 

 able trees you may meet with, their height and circumference. At 

 all your stopping-places you will take a reading of the barometer, 

 and the thermometers will be read every six hours, and as often 

 besides as your change of altitude may make it desirable. As it is 

 one great object to ascertain the height of all ranges, you will be par- 

 ticular in noting the barometer on them, and it will be desirable for 

 some one of the party to ascend all remarkable hills : the barometer 

 will also be sent; it is hoped that great care will be taken that it is 

 not injured. 



It may be desirable for Dr. Pickering and Mr. Brackenridge to 

 make occasional short excursions from your direct route ; you will in 

 that case afford them all the facilities in your power to promote their 

 researches. 



You will study the safety as well as the comfort of your party, and 

 bear in rnind particularly the instructions for the treatment of the 

 natives in my General Order of May 1st, 1841. 



Finally, you are not to deviate from the route pointed out, unless 



