Before proceeding to the consideration of any other of the substances we have proposed to treat of, it may not be improper, here, to annex (more in the form of notes) a few facts illustrative of the history of the very interesting mineral which has occupied our attention in the preceding remarks. Of all the metals, iron is the most widely and universally distributed, being confined to no particular formation as its repository, but discoverable in every class of rocks, from the oldest granite to the newest alluvial deposit. It is also the most abundant of the metallic ores: whole mountains composed of it occurring in the northern parts of the globe. As instances of the great masses in which it is found, it may be mentioned, that the sparry iron ore found in the floetz limestone in Stiria, has been worked to an immense extent and with great profit, for more than twelve hundred years: and, that the Rio mountain in the island of Elba, five hundred feet in height and three miles in circumference, known at an early day to the Romans, (in which mines are still wrought,) is wholly composed of specular iron ore. Though this metal, as we have stated, exists in every kind of rock and soil, it has been remarked, that the dark oxides or its richest ores are confined exclusively to primitive rocks. The ores are generally, it has also been observed, of a purer quality, and more abundant in northern regions. What are denominated iron-stones, or the ores containing a larger proportion of earthy matter, are found in the secondary strata, and exist commonly in great abundance in those accompanying coal. Although iron was known in the remotest ages, and was in use among some particular nations even at a time anterior to the deluge, according to Moses, (Gen. iv. 22) we are not to presume it was in general use: "Him Tubal nam'd, the Vulcan of old times The sword and falchion their invention claim; And the first smith was the first murderer's son."