twenty-five miles in thickness, and still holds within this great covering or shell, a molten mass of subterranean fires, and that volcanic outbursts occur only within certain lines-probably those where the earth's shell is thinnest. It has been noted that the eruptions are more frequent-in fact, take place altogether-where the earth's surface is raising, being pushed up by the mighty forces within its shell. Eruptions never occur in lines where the crust is sinking or undergoing a depression, on account, no doubt, of its immense weight, thickness, and the additional strength it has acquired from cooling. The theory, sometimes advanced, of the cracking and rending of the cooling shell, and allowing the waters of the seas to penetrate to the subterranean fires, with the consequent eruptive forces created by steam, would more than explain the earthquake phenomena. That the earth's shell would close again, after admitting just enough water to give an exhibition, such as we see in volcanic outbursts, is very doubtful. It is more than likely that the two elements, fire and water, coming together in the manner described, would rend the world from pole to pole, and leave us little but the theory to contemplate, if that.

The cause of earthquakes has already received considerable attention, particularly those continually occurring all over the world, unaccompanied by volcanoes. Earthquakes with the wave motion, attended by an indescribable rumbling roar, are judged to be the offspring of restless subterranean fires; while others, with the quick-recurring, nervous shocks, and of which California furnishes many examples, are accounted for by electrical movements taking place between the great elements, earth, air and water. Again, these

apparent electric shocks are explained, by assuming the crust of the earth to be opening in cracks and fissures, and that the formations are slipping, one by the other, giving such a motion to the surface, as one may experience by forcing the moistened finger over a surface of glass.

CHAPTER XVII.

COMMERCE, AND INTEROCEANIC CANALS.

R

A storm-cloud, lurid with lightning,

And a cry of lamentation,

Repeated and again repeated,

Deep and loud

As the reverberation

Of cloud answering unto cloud,

Swells and rolls away in the distance,

As if the sheeted

Lightning retreated,

Baffled and thwarted by the winds' resistance.

LONGFELLOW (Christus).

EVERTING again to the commercial interests locked up in a great portion of the island world,

and which but awaits the key of American energy and enterprise to open and develop, the reader may find the following chapter entertaining, by taking a general glance with me at some of the interests likely to affect the commerce and industries of America.

Professor Hanks says: As the domestic, and the other material interests of California, have prospered and expanded, so also has the commerce of the country grown into large proportions. With an import trade second only to that of New York, San Francisco has such virgin fields to occupy, as open not to her great eastern rival. To her the trade of

Australia and the Orient, including Eastern Siberia and the islands of the Pacific, geographically as well as commercially, belongs; time, freights, interest and insurance all being in her favor, as against every other port in the world.

Although the trade of San Francisco, which may be said to represent largely that of the State, has suffered in some of its departments, through the construction of two additional transcontinental railroads-the one to the north, and the other to the south, of the more central route-it still continues large, and has even increased in the aggregate, since the completion of these lateral lines, indicating that this trade is not likely to be seriously crippled by this or other interfering causes.

The value of the merchandise and treasure shipped from San Francisco in 1883, amounted to $105,000,000, of which $46,000,000 were consigned to foreign countries. Of these exports, $60,000,000 went by sea, and $45,000,000 by rail. The imports from foreign countries amounted, meantime, to $40,000,000; the following staples, among other leading articles, having been imported in the amounts here mentioned: Sugar, 133,914,154 pounds; rice, 58,315,750 pounds; tea, 20,960,248 pounds; and coffee, 17,444,777 pounds. The receipts of lumber at this port amounted, for the year, to 276,772,469 feet, valued at $5,000,000; receipts of Federal revenue, $12,558,305.

The innumerable plants and trees in the Pacific, whose bark, pith and fiber, now worked in a crude way among the natives, into paper, cloth and fibrous manufactures, could be built up into a large profitable trade under more civilized rule. The pulp could be pressed, dried, and shipped, say to San Fran

cisco, where a paper, rivaling the celebrated linen products of that article, manufactured in Europe, could easily be produced.

The black walnut, Spanish cedar, toa, tomano and prima vera, the rosewood, dye-woods and mahogany, growing so profusely in the island world, the satin, sandal and camphor trees, back up the assertion that immense commercial transactions with the Pacific Islands are in the near future.

The cordage interests might be developed in much the same way, by importing the many forms of the raw material, which nature produces in the Pacific Islands, and manufacturing them into the various articles required in our advanced civilization. As the reader is already familiar with many of the natural and cultivated products of the island world, a repetition here would prove uninteresting. The return trade of America with the islands is growing rapidly from year to year. Our breadstuffs, dry goods, canned goods, clothing, hardware, machinery, lumber, etc., now forming a considerable part of the shipping lists of commodities being forwarded to the Pacific Islands, are growing in quantity and value from year to year.

So vast and valuable are the commercial interests of the islands of the Pacific, that estimated on the actual product of the Hawaiian group alone, and this on their exports only, and that to one port, San Francisco, that any estimate on the commercial possibilities of the future, would but excite the doubt and ridicule of the skeptical reader,

In round numbers, the export of the above islands to the port named, is say, 100,000 tons per annum. In comparison with the area of the available lands located in the Pacific, the above group would constitute