TEJON PASS—GRADES, ETC. 23 
I will now give the results of the survey, merely mentioning here that the profile, as deter- 
mined by the spirit-level and by the barometer, agreed remarkably well, seldom differing fifty 
feet, even with the ordinary mode of calculation, which is much less refined than if the minute 
corrections had been applied. This subject will be elaborately discussed in another place, and 
hence it is thought sufficient to mention here the simple fact, without further remark. 
From the Depot camp to the point where the Tejon creek debouched from the mountains was 
a distance of two and eight-tenths miles, over unbroken ground. To the eye this appeared 
very slightly deviating from horizontality. The level showed a difference of altitude of 483 feet, 
giving a grade of 173 feet to the mile. The barometer made the difference of level 15 feet 
greater. I was surprised at this result, which taught that very erroneous impressions must 
generally be conceived with regard to differences of level if the eye alone is trusted to. 
From the entrance of the pass to the point where the precipitous ascent before mentioned 
commences, and where a tunnel must commence, is a distance of eleven and four-tenths miles, 
and the difference of altitude was found to be 2,665 feet, giving an average grade of 234 feet to 
the mile, the minimum grade between any two stations being 150 feet per mile for half a mile, 
and the maximum being 383 feet per mile for nine-tenths of a mile. The barometer made the 
total difference of level 44 feet less. 
The annexed sketch was taken from the crest, and the observer is supposed to be looking 
westward, through the valley of the pass, to the plains of the Tulare valley. . 
Sn = + 
TULARE VALLEY, FROM THE SUMMIT OF TEJON PASS. 
From this point, going eastward, we have an ascending grade of 2,207 feet to the mile, to the 
crest; then a descending grade of 728 feet, to a point on the eastern slope where the descent 
4€ 
