160 . RESOURCES OF CALIFORNIA. 



in the air, with its houses and shipping. The picture was 

 clearly distinguishable for several hours, but repeatedly 

 changed with the clouds, the objects reflected being often 

 magnified and distorted. Beautiful mirage pictures have on 

 rare occasions been seen at San Francisco. 



118. Mud -Volcanoes. In the Colorado Desert, about lati- 

 tude 33 25', and longitude 115 45', are some remarkable 

 mud-volcanoes. They are in that part of the desert below the 

 level of the sea ; and if the water of the ocean were turned 

 in upon that low land, they would be lost to sight. As it is 

 now, they are very rarely visited, because they are in a region 

 so desolate, that an excursion to them is accompanied by seri- 

 ous hardships. The volcanoes cover a space of a quarter of a 

 mile long, and an eighth of a mile wide ; this area is of soft 

 mud, through which hot water and steam are constantly es- 

 caping. The noise can be heard at a distance of ten miles, 

 and the steam is visible at a greater distance. The quantity 

 of water thrown up is small ; that of the steam, great. The 

 vapor rises steadily in some places, with a hissing noise ; in 

 other places, it bursts out with the noise and action of an ex- 

 plosion, throwing the mud a hundred feet into the air, with a 

 loud report. 



' There are places where the mud is in constant movement, 

 and rises in great bubbles, and bursts, as if boiling with in- 

 tense heat ; while in other places, regular cones, apparently 

 hardened into permanency, and with shapes varying from low 

 hillocks to sharp points, have been formed. There are boil- 

 ing springs, which throw up their water twenty or thirty feet ; 

 and there are large basins, one hundred feet across, and five or 

 six feet below the general surface, in which a bluish paste is 

 continually boiling. Some of the springs are surrounded by 

 incrustations and arborescent concretions of carbonate of 

 lime ; others are encircled by deposits of sulphur. The air 

 blown from the salses is fetid with sulphur. It is very danger- 

 ous to approach the springs and cauldrons, because the whole 



