Near the sulphur bank, on the edge of the lake, is a hot borate spring, which is supposed to yield at times three hundred gallons per minute, and which Professor Whitney, the State Geologist, declares remarkable for the extraordinary amount of ammoniacal salts its waters contain--more than any natural spring water that has ever been analyzed.
There is abundant evidence of volcanic action in all the country about Clear Lake.

A dozen miles from Lakeport, not far from the shore of the lake, the whole mountain side along which the stage-road runs is covered for several miles with splinters and fragments of obsidian or volcanic glass, so that it looks as though millions of bottles had been broken there in some prodigious revelry; and where the road cuts into the side of the mountain you see the osidian lying in huge masses and in boulders.
Joining this, and at one point interrupting it, is a tract of volcanic ashes stratified, and the strata thrown up vertically in some places, as though after the volcano had flung out the ashes there had come a terrific upheaval of the earth.
The two borax lakes lie also near the shore of Clear Lake; the largest one, which is not now worked, has an area of about three hundred acres.
Little Borax Lake covers only about thirty acres, and this is now worked.
The efflorescing matter is composed of carbonate of soda, chloride of sodium, and biborate of soda.

The object of the works is, of course, to separate the borax, and this is accomplished by crystallizing the borax, which, being the least soluble of the salts, is the first to crystallize.
The bottom of the lake was dry when I was there; it was covered all over with a white crust, which workmen scrape up and carry to the works, where it is treated very successfully.

My nose was offended by the fetid stench which came from the earth when it was first put in the vats with hot water; and I was told by the foreman of the works that this arose from the immense number of flies and other insects which fly upon the lake and perish in it.

Chinese are employed as laborers here, and give great satisfaction; and about eight days are required to complete the operation of extracting the borax in crystals.
Earth containing biborate of lime is brought to this place all the way from Wadsworth, in the State of Nevada--a very great distance, with several transhipments--to be reduced at these works; and it seems that this can be more cheaply done here than there, where they have neither wood for the fires nor soda for the operation.
Clear Lake is but twelve hours distant from San Francisco; the journey thither is full of interest, and the lake itself, with the natural wonders on its shores, is one of the most interesting and enjoyable spots in California to a tourist who wishes to breathe fresh mountain air and enjoy some days of free, open-air life.
The visitor to Clear Lake should go by way of the Napa Valley, taking stage for Lakeport at Calistoga, and return by way of the Russian River Valley, taking the railroad at Cloverdale.