548 APPENDIX. 



The men whom Mr. Rodgers is to engage at the Willamette 

 settlement, will require of you particular attention. You will know 

 their terms of engagement; for the performance of which, and their 

 good behaviour, their pay will be made answerable. 



You will observe strictly the following instructions : 



1st. The route I have pointed out to you is believed to be feasible, 

 but as the country is unknown, it may not be so. You are not at 

 liberty to depart from it, however, without good and sufficient reasons. 



You will, however, particularly note : my object is to get all the 

 information respecting the district I have marked in red, and you 

 will endeavour to get this as accurate as possible, by travelling over 

 as much of its surface as your time will admit of. 



2d. Your absence is limited to the 10th of September, and I am 

 convinced that much knowledge may be gained of the district pointed 

 out to your party in that time. 



3d. Observations for latitude and longitude wherever you may 

 encamp. 



4th. You will keep an accurate map of your route, noting on it all 

 lakes, rivers, plains, mountains, and every thing worthy of notice, to 

 illustrate its features. For this purpose, furnish yourself with a 

 blank-book of foolscap size, and use each leaf for a day's work ; the 

 ruled places will answer the purpose of a scale, and be sufficiently 

 large to insert every thing desirable to note. 



5th. You will be furnished with a pocket chronometer, sextant, 

 artificial horizon, prismatic compass, barometer, thermometers, Nau- 

 tical Almanac, and Book of Tables, which will enable you to obtain 

 all kinds of observations ; and I shall expect you to be very particular 

 and untiring in their use. Much of the information desired will 

 depend upon their use, and will demand your exertions and diligence. 



Observations will be obtained daily, if possible, both for latitude 

 and longitude. 



The meridian altitude of the sun, by the artificial horizon, you will 

 observe daily if possible, also that of the north star ; this observation 

 you will find easy after a little practice, by bringing the two reflected 

 images to cover each other. It is necessary to get the error of your 

 watch in mean time by a star, east or west, to find the true time. 



This can be done immediately before or after the observation by 

 the north star, and be better than to depend upon the rate of your 

 chronometer, which may alter in riding, though it is not probable it 

 will much. It must be carried in the chronometer-fob of your waist- 



