7 NATURAL PHILOSOPHY. CHAPTER I. MATTER AND ITS FORMS. 1. Matter.-Whatever occupies space, whatever we can see or touch, is known as Matter. Earth, water, air, are different forms of matter. A distinct portion of matter is called a Body. The Earth, a ball, a rain-drop, are Bodies. 2. All matter, properly speaking, is Ponderable,—that is, has weight. Imponderable means without weight. The term Imponderable Matter has been applied by some to heat, light, electricity, and magnetism. As late researches seem to indicate that these are forces or conditions of matter, and not themselves varieties of matter, they are now generally called Imponderable Agents. 3. Forms of Ponderable Matter.-Ponderable Matter exists in three forms; Solid, Liquid, and A-er'-i-form. A body is said to be Solid when its particles cohere, so that they can not move among themselves; example, ice. Solid bodies are called Solids. 1. What is Matter? Give examples. What is a Body? Give examples. 2. What is said of all matter? What does imponderable mean? To what has the term imponderable matter been applied? What are heat, light, electricity, and magnetism generally called? 8. In how many forms does ponderable matter exist? A body is said to be Liquid when its particles cohere so slightly that they can move freely among themselves; example, water. Liquid bodies are called Liquids. Aëriform means having the form of air, and matter is said to exist in this state when its particles repel each other, tending to separate and spread out indefinitely; example, steam. Aëriform bodies are called Gases and Vapors. Liquid and aëriform bodies are embraced under the general name of Fluids. There are marked points of difference between solids and fluids. A solid has a permanent shape; a fluid accommodates its shape to that which contains it. A solid may often be moved by moving a portion of its particles; as a pitcher by its handle. The particles of a fluid, on the other hand, do not cohere, and therefore, when we move some of them, the rest are detached by their own weight; thus by dipping a tumbler into a pail of water, we can not remove all the fluid, but only as much as the tumbler contains. Again, a solid resists a force which seeks to penetrate it. A fluid, on the contrary, is easily divided; if we move slowly through the air, for instance, we feel no resistance. The same substance may, under different circumstances, appear in all three of these forms. Thus water is a liquid; when frozen, it becomes ice, which is a solid; when exposed to a certain degree of heat, it is converted into steam, which is aëriform. 4. Classes of Bodies.-Bodies are distinguished as Simple and Compound. A Simple Body consists of matter that can not be resolved into more than one element; as, gold. A Compound Body consists of matter that can be resolved into two or more elements; as air, which is composed of two gases. The simple bodies, or elements, of which every thing in the universe is composed, are sixty-two in number. Of these, fifty, distinguished by a peculiar lustre, are called Metals. The remaining twelve are known as Nonmetallic Elements. Name them. When is a body said to be solid? What are solid bodies called? When is a body said to be liquid? What are liquid bodies called? What does aëriform mean? When is a body said to be aëriform? What are aëriform bodies called? What name is applied to both liquid and aëriform bodies? Mention some of the marked points of difference between solids and fluids. In how many forms may the same substance appear? Give an example. 4. Into how many classes are bodies divided? Name them. What is a Simple body? What is a Compound body? How many simple bodies are there? How are they divided? Name the principal met The principal metals are the seven known to the ancients.-gold, silver, iron, copper, mercury, lead, and tin; antimony, which was next discovered, in 1490; bismuth, zinc, arsenic, cobalt, plat'-i-num, nickel, manganese, &c. The twelve non-metallic elements are ox'-y-gen, hy'-dro-gen, ni'-tro-gen, chlorine [klo'-reen], iodine [i-o-deen], bromine [bro'-meen], fluorine [flu'-oreen], se-le'-ni-um, sulphur, phosphorus, carbon, and bo'-ron. These simple substances are rarely found; nearly every body that we meet with, whether natural or artificial, is composed of two or more elements, and is therefore compound. Such is the case with air, which was anciently thought to be a simple substance, but was proved, towards the close of the eighteenth century, to be a mixture of 21 parts of oxygen and 79 parts of nitrogen. Water, also, has been found to be a compound substance, made up of oxygen and hydrogen combined in the proportion of 1 to 8. Of the sixty-two elements referred to above, twenty are so rare that their properties are not yet fully known; thirty more are comparatively seldom met with; the remainder constitute the great bulk of the globe and all that is thereon. The consideration of the simple substances, with their properties and combinations, belongs to the science of CHEMISTRY. The force that causes them to combine and produce compound substances, is called Chemical Affinity. Oxygen and hydrogen combine and form water, in consequence of their chemical affinity. Chemical affinity subsists only between certain substances. If sulphuric acid be poured on a piece of zinc, the two substances will combine and form a compound entirely different from either. Pour the acid on a lump of gold, and no such change will ensue, because there is no chemical affinity between them. 5. Natural Philosophy.-Natural Philosophy is the science that treats of the properties and laws of matter. It is also called PHYSICS. Pythagoras was the first to use the term philosophy. From him and his followers it was borrowed by Socrates; who, when the other sages of his time called themselves sophists, or wise men, modestly declared himself a philoso pher, or lover of wisdom.-Philosophy implies a search for truth; and Natural Philosophy, as distinguished from Moral and Intellectual Philosophy, searches for the truths connected with the material world. als. Name the twelve non-metallic elements. What is said of the simple substances? What kind of substances are air and water? Of what is air composed? Of what, water? How many elements constitute the great bulk of the globe? What is said of the rest? To what science does the consideration of the simple substances belong? What causes the simple substances to combine? Give an instance of chemical affinity. Illustrate the fact that chemical affinity subsists only between certain substances. 5. What is Natural Philosophy? With whom did the term philosophy |