One of the most useful and abundant metals; being found in all mineral earths, and stones; in plants, and animal fluids; and is the chief cause of the varieties of color in all. Iron is found in great masses, in various states, in the bowels of the earth; it is usually, however, compounded with stone, from which it is separated by the action of fire. In some parts of the world, whole mountains are formed of iron; among these may be mentioned the Pilot Knob and the Iron Mountain, in Missouri, being unsurpassed by anything of the kind found elsewhere. What are its characteristics? It is hard, fusible, not very malleable, but extremely ductile, and very tenacious; it is of a greyish color, and nearly eight times heavier than water. Without iron, society could make no progress in the cultivation of the ground, in mechanical arts or trades, in architecture or navigation; it is therefore of the greatest use to man. Iron tools have been used in all European countries as long as their histories have existed; this metal appears likewise to have been known and used by the inhabitants of the world in the earliest ages, being frequently mentioned in the Holy Scriptures. In the fourth chapter of Genesis, Tubalcain is spoken of as "a hammerer and artificer in every work of brass and iron," and thus their existence was evidently known at that early period of the world. _Artificer_, one who works or makes. _Fusible_, capable of being melted by fire. [Illustration: THE SALT MINES OF WIELICZCA.] What do you mean by Metals? Useful substances dug from the bowels of the earth, being sometimes found pure, but mostly combined with other matter. They are distinguished by their weight, tenacity, hardness, opacity, color, and peculiar lustre, known as the metallic lustre; they are fusible by heat, and good conductors of heat and electricity; many of them are malleable, and some extremely ductile. Those which were first known are gold, silver, iron, copper, mercury, lead, and tin. _Tenacity_, the firmness with which one part adheres to another. _Opacity_, want of transparency or clearness. What are Metals called in their natural state? Ores; so named because the metal contained in them is either mixed with other metals, or with mineral earths, from which they are separated and purified by various means: such as washing, roasting, &c., but the method is always regulated by the nature of the ore. What is Copper?