CLIMATE. 39 
constant decomposition of animal and vegetable manner, lying 
on wet ground, under a hot sun, causes the air in other states 
to be filled with such gases as are not set free to an equal 
extent here. 
In May and June, all California dries up”—the rivers, the 
brooks, the springs, the ditches, the vegetation—and, with’ 
them, many of the resources of the country. 
§ 29. Length of Days.—tThe shortest day in the year, the 
20th of December, measures nine hours and four minutes be- 
tween sunrise and sunset at Crescent City, and ten hours at 
San Diego; while the longest day, the 20th of June, measures 
fifteen hours and seventeen minutes on the southern border, 
and fourteen hours and nineteen minutes on the northern bor- 
der of the state—or, measuring from the beginning of twilight 
in the morning to the end of twilight at night, the day meas- 
ures nineteen hours and forty-seven minutes on the Siskiyon 
Mountains, and seventeen hours and forty-three minutes at 
Fort Yuma. 
8 30. Thunder-Storms.—Thunder-storms are very rare in 
California. Lightning is not seen more than three or four 
times a year at San Francisco, and then it is never near, but 
far off, playing about the peak of Mount Diablo. Thunder is 
still more rare. Indeed, many persons have been here for 
years, and cannot say that they have ever seen the one or 
heard the other. During eleven years’ residence in the state, 
I have never seen a brilliant flash of lightning or heard a loud 
clap of thunder. Thunder-storms are sometimes witnessed 
high up in the mountains, and in the Great Basin; very rarely 
in any of the low land of the state. In May, 1860, a house in 
Sonora was struck by lightning; and in February, 1861, three 
vessels in Humboldt Bay were struck in the same manner: 
and, though there were persons in the house and on all the 
vessels, no serious injury was done to either person or prop- 
erty in any case. On the 25th of May, 1860, a Chinaman was 
