PREFACE.

'T'HE personal observations of the author on which thisbook is based commenced with the ascent of Vesuvius in 1834, and, the next month, a sight of Stromboli and atramp after minerals on the solfataric island of Milo. Theywere continued in 1838 by short excursions on Madeira andone of the Cape Verds; in 1839, by studies of the extinctvolcanic regions of Tahiti, Tutuila and Upolu, and thebasaltic outflows and overflows of Illawarra and other partsof New South Wales . They were further extended in 1840by observations in the Feejees, and by explorations of theactive and extinct volcanoes of the Hawaiian Islands; in1841, by observations on a crater in the coast region ofOregon , instructive though distant views of some of the loftycones of the Cascade Range , and a brief survey of an extinctvolcano on the Sacramento (now called Marysville Butte)during an overland trip from Vancouver to San Francisco ;and, finally, in 1860 by a second visit to Vesuvius , and in1887 a second to the Hawaiian Islands.

The purpose of the work is the illustration of volcanicaction and principles by special reference to the facts sup-plied by the great, open, free-working craters of Hawaii , andby comparing and contrasting these with the correspondingfeatures and phenomena of Vesuvius . It commences withan elementary treatise on volcanoes and volcanic action, that