XI 



APPENDIX A. 



&7V 



ASTRONOMICAL OBSERVATIONS WITH SEXTANT. 



I. Observations on the route of the main party from Benicia to the point where the command 

 separated, near the Three Sisters, Oregon Territory. 



CAMP 7— JULY 15, 1855. 

 Observer — Lieut. R. S. Williamson, U. S. Top. Engineers. 



Object observed. Time of observ'n 



by cbronometer. 



Altair. 



Arcturus. 



Pola 



h. m. s. 



9 31 33.5 



33 48.0 



34 50.0 

 3G (.9.0 



37 26.5 



38 46.0 



39 56.5 



16 

 18 

 20 

 21 

 22 

 24 

 25 



07.0 

 20.0 

 13.5 

 27.5 

 52.0 

 17.0 

 28.0 



9 00 32.5 



9 02 411.5 



9 114 43.0 



9 07 05.5 



9 08 27.5 



9 10 07.5 



9 12 15.0 



Observed double 

 altitudes. 



d m. s. 



88 46 30 



89 22 00 



89 42 30 



90 08 00 



90 34 20 



91 00 30 

 91 23 20 



100 47 50 



100 02 10 



99 17 00 



98 51 20 



98 h 



97 46 



10 

 10 



97 20 30 



77 46 20 



77 46 30 



77 46 50 



77 48 10 



77 49 20 



77 50 20 



77 52 10 



Index error • 

 momeler 69°. 



-lO C6' 35". Barometer 29.8 in. Ther- 



CAMP 11— JULY 19, 1855. 

 Observer — Lieut. R. S. Williamson, U. S. Tup. Engineers. 



CAMP 11— JULY 19, 1855— Continued. 

 Observer — Lieut. R. S. Williamson, U. S. Top. Engineers. 



Object observe.!. 



Time of observ'n 

 by cbronometer. 



Polaris. 



Observed double 

 altitudes. 



d. m. s. 



79 00 50 



79 01 10 



79 05 30 



79 04 50 



79 06 10 



79 08 20 



79 08 50 



79 09 20 



79 09 40 



7!) J2 10 



Index error —2' 15". Barometer 29.7 in. Thermometer 

 780. 



FORT READING— JULY 22, 1855. 

 Observer — Lieut. R. S. Williamson, U. S. Top. Engineers. 



a Cygni. 



Arcturus. 



Polaris. 



h. 

 9 

 9 

 9 

 9 

 9 

 9 



9 

 10 

 10 

 10 

 10 

 10 



9 

 9 

 9 

 9 

 9 

 9 



m. 

 46 

 47 

 49 

 51 

 52 

 54 



57 

 00 

 02 

 04 

 06 

 07 



21 

 23 

 26 

 29 

 31 

 32 



55.0 

 11.5 

 37.0 

 28.5 

 11.0 

 55.5 



35.0 

 00.0 

 38.5 



06.0 

 27.0 

 59.5 



73 58 40 



73 05 40 



72 1 1 30 



71 28 20 



70 49 50 



70 10 00 



79 44 20 



79 44 40 



79 47 50 



79 49 30 



79 51 10 



79 53 00 



Index error 

 mometcr, 85°. 



•2' 15". Barometer, 29.6 in. Tncr- 



