The southernmost island, which is the largest—­just as Hawaii, the southernmost of the Sandwich Island group, is also the biggest—­extends for nearly a mile east and west, and is three hundred and forty feet high.  It is composed of broken and water-worn rocks, forming numerous angular peaks, and having several caves; and the rock, mostly barren and bare, has here and there a few weeds and a little grass.  At one point there is a small beach, and at another a depression; but the fury of the waves makes landing at all times difficult, and for the most part impossible.

The Farallones are seldom visited by travelers or pleasure-seekers.  The wind blows fiercely here most of the time; the ocean is rough; and, to persons subject to sea-sickness, the short voyage is filled with the misery of that disease.  Yet they contain a great deal that is strange and curious.  On the highest point of the South Farallon the Government has placed a light-house, a brick tower seventeen feet high, surmounted by a lantern and illuminating apparatus.  It is a revolving white light, showing a prolonged flash of ten seconds duration once in a minute.  The light is about three hundred and sixty feet above the sea, and with a clear atmosphere is visible, from a position ten feet high, twenty-five and a half miles distant; from an elevation of sixty feet, it can be seen nearly thirty-one miles away; and it is plainly visible from Sulphur Peak on the main-land, thirty-four hundred and seventy-one feet high, and sixty-four and a half miles distant.  The light-house is in latitude 37 deg. 41’ 8” north, and longitude 122 deg. 59’ 05” west.

On our foggy Western coast it has been necessary to place the light-houses low, because if they stood too high their light would be hidden in fog-banks and low clouds.  The tower on the South Farallon is, therefore, low; and this, no doubt, is an advantage also to the light-keepers, who are less exposed to the buffetings of the storm than if their labor and care lay at a higher elevation.

As the Farallones lie in the track of vessels coming from the westward to San Francisco, the light is one of the most important, as it is also one of the most powerful on our Western coast; and it is supplemented by a fog-whistle, which is one of the most curious contrivances of this kind in the world.  It is a huge trumpet, six inches in diameter at its smaller end, and blown by the rush of air through a cave or passage connecting with the ocean.

One of the numerous caves worn into the rocks by the surf had a hole at the top, through which the incoming breakers violently expelled the air they carried before them.  Such spout-holes are not uncommon on rugged, rocky coasts.  There are several on the Mendocino coast, and a number on the shores of the Sandwich Islands.  This one, however, has been utilized by the ingenuity of man.  The mouth-piece of the trumpet or fog-whistle is fixed against the aperture in the rock, and the breaker, dashing in with venomous