ways lived in a city, and had the name of being a good Latin scholar for a lad of fifteen. George, who was the son of a farmer near Glenwild, was fourteen years old, and was called good at figures, while John, whose father was a miller some miles up the valley, had astonished the gazing rustics by the ingenious contrivances he had introduced into a model mill, constructed by his own hands before he was thirteen years of age. He was now seventeen.

3. Ida, who was fifteen, had studied philosophy at a fashionable boarding-school, where they had a new and easy conveyance up the hill of science, something after the style of a sedan chair, in which she had paid her fare. Ella, as we have said, was the daughter of Mr. Maynard, and, from her familiarity with various pieces of apparatus, had gained many ideas of the study which she now for the first time engaged in; but she thought herself but a beginner, as her first lesson had not yet been recited.

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4. "Who was the author of the lines I just repeated ?" said Mr. M. "Virgil said about the same thing," replied Frank. 'Right," said the teacher; "and the study is no less pleasing to boys and girls than to men, and no less pleasing now than it was two thousand years ago. Yes, Virgil was right. The study that leads to the explanation of the general properties2 of bodies, and the laws which they obey, is most delightful.

5. "The word philosophy," continued Mr. Maynard, "means a love of wisdom or knowledge; and one who consistently applies himself to acquire it is a philosopher, or lover of knowledge. Like Norval's father, whose constant care was to increase his store,' the student of philosophy should constantly seek to know the causes of things.

6. "As all our knowledge of things around us is derived3 through the medium of the senses-seeing, feeling, hearing, tasting, and smelling, and we may add lifting-the advice of Brutus to the Romans, 'Awake your senses, that you may the better judge,' applies to those who would study philosophy. They should be accurate observers of Nature; and in the boundless field which Nature opens they will find abundant materials to interest and instruct them.

7. "But let me explain to you, my young pupils, the nature of the study we are about to engage in. We shall have to learn why the balloon rises in the air, as well as why the diving-bell sinks in the water; how images are reflected from mirrors, or permanently fixed on metal or paper by the photographer; why water rises in a common pump, or is thrown by engines on the blazing building; how invisible wonders are revealed by the microscope, and the myriads of stars, unseen by the naked eye, appear by aid of the telescope; how, by the same wind, vessels can sail in opposite directions; what turns the needle toward the pole, or conveys intelligence with lightning speed; the causes of clouds and rainbows; of winds, and dew, and rain; of thunder and of lightning. The barometer, the thermometer, and the various instruments of modern scientific investigation will also claim our attention.”.

8. Here Miss Ida ventured to remark that she had often seen the expression, "the charms of Nature," and had always supposed the study of Nature was more poetical than philosophical-that it treated of such things as beautiful scenery, and birds, and flowers, and winding streams, and cooling fountains; and that, while it was a very pleasant and agreeable study, it was not particularly useful.

9. "I am not surprised," said Mr. Maynard, "that you should have entertained this view of the study of Nature, for it is the view most frequently expressed in poetry; but it is only a partial view of that great subject. We shall find, as Hamlet expresses it, that 'there are more things in heaven and earth than are dreamed of in our philosophy,' if our knowledge of Nature has been limited to its outward aspects, to the neglect of the great principles and laws, of which the charms of Nature' that you speak of are merely the outward expression."

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10. Ida did not seem fully to understand these remarks, and Mr. Maynard continued: "It will afford me much pleasure to illustrate the truths of philosophy by many pleasing and instructive experiments, as we meet from time to time. I will assign you a subject for our next interview, and hope you will find out all you can about it from any books you may have on Philosophy, as well as from conversation with

your schoolmates and others. In order to aid you in your pleasant task, I will allow you to examine any books in my own library, and I assure you you will find much interesting matter for our conversations in books not called Philosophies. Our first topic will be the Properties of Matter."

11. With this introductory explanation of the nature of the subject, Mr. Maynard dismissed his pupils, who, however, stopped a short time on the lawn in front of the building, talking over various topics which his remarks had suggested. Then they separated to make preparations for the enjoyment of their Saturday's holiday. Ida and Ella, accompanied by Frank, and Ella's younger brothers Edward and Charles, were going down the glen to gather wild flowers; and John and George were going, as usual, to their respective homes to pass the Sabbath, and return to school on the Monday following.

ISO-LIC'-IT-ED, earnestly requested.

14 ME-DI-UM, the means or instrument.

2 PROP-ER-TIES, the peculiar or essential 5 PHO-TOGʻ-RA-PHER, one who takes pictures qualities of a thing; thus, extension and figure are properties of bodies.

3 DE-RIVED', received; obtained.

by the daguerreotype.

6 EN-TER-TAIN'ED, had; had in mind.
17 As'-PECTS, appearances.

LESSON III.

THE PROPERTIES OF MATTER.

1. SATURDAY morning having arrived, the members of our Volunteer Philosophy Class were again assembled in the library at the hour appointed. As they had frequently talked over the subject of the lesson with each other during the week, and had found some difficulties attending it, the remarks of the teacher were looked forward to with much interest. Mr. Maynard, having requested them to be seated, thus began:

2. Mr. M. Strange as it may seem to you, my young pupils, some learned men have denied the existence of every kind of matter whatever. Berkeley, the ingenious Bishop of Cloyne, whose portrait is conspicuous in the Trumbull Gallery of Paintings in Yale College, was one of those philosophers who in earnest argument denied that there is any matter. Of him Byron wrote,

"When Bishop Berkeley said, 'There was no matter,'
And proved it, 'twas no matter what he said."

3. I have heard of the following sensible answers to two important questions. "What is matter? Never mind. What is mind? No matter." But who will answer the question, "What is matter ?"

4. Ida. All things which we see or feel are composed1 of matter.

Mr. M. That is doubtless true, and yet it is hardly a definition. It is difficult to define matter in few words, but we may say it is the substance of which all bodies are composed. It may exist either in the form of a solid, as ice, or in a liquid state, as water, or in a gaseous condition, as steam, and yet be the same matter. Can you think of any matter that does not occupy some space?

5. John. I can not. I was thinking the other day of the space occupied by the finest particle of the finest flour; that it must be something, since enough of these particles may be collected to fill a barrel or freight2 a ship.

Mr. M. And did it occur to you, John, that what you call a particle of the finest flour is itself composed of millions of atoms, of which there are at least three different kinds in the fine flour dust'?

John. I can not think of atoms so small as they must be. 6. Mr. M. I hope that before you leave this school you will be able to think of the atoms of the flour dust, and not only that, but think of an atom of one kind as being eight times the weight of an atom of another kind. Science3 will enable us to weigh the atoms, invisible though they are, in relative terms; and also to weigh the earth, moon, planets, comets, and even the sun. But if every atom of matter must occupy some space, can two atoms occupy the same space at the same time'?

7. George. No, sir; and is not this the very property call. ed in the books impenetrability ?5

Mr. M. It is; and the property of occupying some space is called extension. As without these two properties we can form no idea of matter, they are said to be inseparable or essential properties. Tell me why the water does not rise in

the inverted tumbler which I plunge beneath the surface of water in the basin.

8. John. Because the tumbler is filled with air, which is one kind of matter, and also owing to the principle of impenetrability; for water and air can not occupy the same space at the same time. I saw a boy who had just entered a drug store as assistant attempt to fill a bottle through a closelyfitting funnel; but the liquid rose up in the funnel, and would not run into the bottle till he attempted to withdraw the funnel, when it was quickly emptied. I think that must have been a dear experiment to him, as the liquid was a strong acid, which ruined his clothes, as it ran over the bottle on the removal of the funnel.

9. Mr. M. Yes, that illustrated the impenetrability of air to the liquid; and very probably, if you had seen the conclusion of the dear experiment, you would have witnessed the breaking of the bottle by the effort to force into the neck a closely-fitting cork when the bottle was already full; and this would have afforded an illustrations of the impenetrability of a liquid to a solid.

George. I think the boy should have taken a few lessons in philosophy before entering upon such a philosophical business.

10. Mr. M. All we do is in accordance with, or in violation of philosophical principles, many of which we shall discuss in these conversations. Whenever we succeed, or have good luck, it is because we observe those principles; and when we fail, it is because we violate them, or act in ignorance of their existence. There are other properties, which do not seem essential to our ideas of matter, and which are nevertheless general properties of matter, or, as they are sometimes called, accidental properties. These are divisibility, porosity,10 inertia,11 figure, and attraction.

11. Ida. I learned these as essential properties of matter. Mr. M. It may not be of much importance to us now to discuss that point, but can you not think of an atom, or indivisible particle? If so, divisibility is not an essential property; for matter may exist without being divisible.

Frank. I have been puzzled to know what is meant in the books by such words as atom, molecule,12 and particle.