CONTENTS. 23 



Stewart Creek. — Hot spring. — Siskiyou Mountains. — Klamath River. — Yreka. — Little Scott's Mountains. — Fort 

 Jones. — Lieut. Crook detained. — Disappointment.— Snow. — Scott's Valley. — Scott's Mountains. — Trinity Valley. — 

 Trinity Mountains. — Clear Creek. — French Gulch. — Shasta. — Fort Heading again, and termination of field work. — 

 Lieutenant Williamson. — Orders from War Department. — Subsequent movements, &c. 



CHAPTER VI. 



Computation of Altitudes from Barometrical Observations. 



Preliminary Remarks. — Instruments. — Instrumental Errors. — Interpolation and approximate test of accuracy in ohservers. — 

 Corrections preparatory to computation: 1, for temperature of mercury ; 2, for instrumental errors; 3, for horary 

 oscillation; 4, for abnormal oscillation. — Method of computation, with remarks: 1, on the reading of the barometer 

 and thermometer at the lower station ; 2, on the reading of the thermometer at the upper station. — Example. — Test 

 of the comparative accuracy of the different methods of computation, with tables showing the results obtained. — 

 Height of Fort Reading ; explanation of tables of barometric observations in Appendix D, &c. 



CHAPTER VII. 



Route from Shasta Valley, Bast of Shasta Butte, to Fort Beading ; Explored by Lieut. B. S. 



Williamson, U. S. Top. Eng., in 1851. 



Explanation. — Party. — Yreka, in 1851. — Start. — View of two passes. — Wright Lake. — Water hole — Porcupine killed. — 

 Turned back. — Pass. — Extended view. — Pumice-stone — Difficult travelling. — No water or grass. — Natural bridge. — 

 Pedregal. — Water in fissure. — Branch of Fall River. — Fall River. — Ford. — Indians. — Pit River. — Tule raft. — 

 Expedient. — Pass through western chain of Sierra Nevada. — Battle Creek. — Cow Creek. — Settlements. 



