Asphaltum. Asphaltum appears to be a very general product of the Island and of the water along its shores. Deposits of it show in every province, in some localities in inexhaustible quantities; the deposits at Cardenas and Santa Clara take the lead in development. As much as ten thousand tons a year have been shipped from Santa Clara. At and near Cardenas the deposits are found in the bottom of the bay, and the method of securing it is peculiar. A shaft eighty feet or more in depth below the surface extends into the sea-bottom; and into this the asphalt runs or filters. It is supposed that the supply is brought from the interior through the subterranean rivers which prevail in this locality,--from which, indeed, Cardenas gets its water supply. Over this shaft the ship is anchored; from her deck a heavy bar of iron attached to a rope is dropped, and the asphalt is broken from the sides of the shaft and falls to the bottom, where it is scooped up into a net and loaded into the vessel. As this work has been going on for years and the asphalt replenishes itself constantly, it is fair to suppose that the run will go on for ever. It is of such quality as to be worth from $80 to $125 per ton in New York, and a ship has gathered as much as three hundred tons in three weeks. This and two other mines, of not such good quality, are immediately in the bay of Cardenas; and near Diana Key is the great Constancia mine, covering a circumference of one hundred and fifty or more feet, from which twenty thousand tons have been taken; yet there is no diminution in the quality of the deposit. There are several other smaller deposits in this locality. As asphalt is so general in Cuba and the mines are so generous in their yield, even under the crude methods adopted, it is only to be concluded that the asphaltum industry of the Island has a bright outlook; and when it is understood what a fine paving material asphalt is, and how greatly paving is needed in the streets of Cuban towns, it seems to be almost providential that so sore a need has healing so close at hand, demanding only enlightenment and energy to apply it.