materials of building: these, arranged and secured by means of pins or nails of the same material, rise in orderly succession one above another, till there is erected for his habitation a comfortable and commodious dwelling:--while the surrounding fields, now that he has ample food in store for their support, are overspread with the flocks he has domesticated, to provide for his use unfailing supplies of clothing and subsistence. Already he has made himself acquainted with the rudiments of agriculture, architecture and manufactures, and has laid the foundation of the useful arts. Compare his condition now, with that in which he existed before his acquaintance with the uses of iron: contrast the savage of the forest with the cultivator of the field--the scanty and precarious sustenance of the one, with the regular and abundant subsistence of the other--the covering of skin, with the garment of wool--the hut, with the commodious dwelling--the hardships attendant on one mode of life, with the numerous conveniences that follow as a necessary train to the other; and from this rough-drawn and very imperfect outline, there may be formed some slight idea of the revolution effected in the condition of man, even by a limited acquaintance with the simpler uses of this single, though most important of all the mineral substances. It is scarcely necessary to direct the reader's attention to the accession to the comforts, the conveniences, the elegancies of life, or to the vast acquisitions to the power of man, which, in successive periods of time, have been gained by a more extended and familiar acquaintance with the various properties of iron, and the innumerable purposes to which, with increased advantage, human ingenuity has discovered it to be applicable. It is sufficient to turn the eye on some great and populous city--the seat of busy manufactures;--on a Sheffield, a Manchester, or a Birmingham,--those nurseries of the arts, and workshops of the world: to view its immense establishments in active operation, and look on the tens of thousands of the industrious they maintain and employ. It is sufficient to hear the eternal din and incessant roar of stupendous machinery, laboring in the service of man, in obedience to laws and impulses he has given to it;--to see its multifarious and complicated parts performing each its allotted movement;--swinging heavily, with measured time, and force, or shooting to and fro with regulated rapidity; revolving slowly, and lazily around, or flying with inconceivable velocity, and whirling smoothly, each in its proper sphere,--moving, all in harmonious cooperation, to effect some beneficial end, with a precision unerring--as if impressed with the intelligence and volition of animated being. It is sufficient, to be convinced of the great acquisition we have in iron, to witness the wondrous effects of the steam-engine,--that giant machine, which performs to our hands the