Natural philosophy, for schools, families, and private students

Front matter

Book^P-53

Ia "^

FOR SCHOOLS, FAMILIES, AND PRIVATE STUDENTS.

Preface

This work, though based upon the labors of the learned, is not a mere compilation.— The author has endeavored to invest the subject with freshness and interest, to enliven the progress of the young, as they climb the hill of science. We have sometimes paused on our way, to discourse of Him who formed the world, and from whose eternal mind the laws of physical science originated. — Our hearts have been warmed and animated with thoughts of the wisdom and goodness which irradiate every page of the volume of nature.

American parents and teachers ; to aid you in your duties, I have labored to prepare this volume. I commit it to you, in the confidence that while it shall impart to your children and pupils the principles of science, it will, at the same time, exert a salutary influence on their moral and religious affections.

In the attempt made to connect religious sentiment with the study of the sciences, I find myself supported by that profound and philosophical writer, Madame Necker De Saussure, from whose second volume on Progressive Education, the following is an extract. " Religion alone unites and connects the various departments of education, external objects with the affections of the heart, the laws of physics with the laws of mind ; it is the influence of religion only which can cause science and duty to meet in the same point. What relation, merely human, could we, for example, find between two subjects in appearance so foreign from each other, as those of physical phenomena, and the moral obligations imposed on man ? and yet a connection exists ; they have one common source. One God, the sovereign legislator of nature and the soul, wills the reign of universal order. He has subjected matter to the laws of an irresistible necessity, and he has imposed on the free agent, man, a necessity which, though it appears less imperious, forces his will by bitter experience of the evils attached to a neglect of duty. When the creations, and laws of one discerning mind, present themselves on every side, and in the government of the universe, numerous relations are seen to exist between the different departments

IV PREFACE.

of knowledge. To the subjects most fitted to exercise the talent of investigation inherent in the mind of man, are connected objects which appear chiefly fitted to his physical wants, and even those which seem created but to please his imagination. If God is the eternal geometrician, who has calculated with exactitude the measure of the different forces in the universe, if he is the wise legislator who has engraven his laws upon our souls, if he is the supreme artist, who has spread forth beauty upon the earth and in the heavens, and has rendered us sensible to its charms ; and as there is nothing in the physical world which is not the immediate work of God, and nothing in the moral world, which does not result from faculties with which he has endowed man, there can be neither object nor thought, which may not be connected with God. Thus all may be linked together, all may harmonize ; ideas, before insulated, unite in the mind of the pupil ; he views creation as a whole ; — and as soon as he perceives the unity of design in nature, his reason, though still feeble, presents some resemblance to the Supreme reason which conceived the design"

To Teachers, I would most solemnly affirm as the result of my experience in education, that the only effectual method of improving the characters of pupils is through the influence of religious truths; — and that intellectual culture may be so conducted as to lend most important aid in the great work of Christian Education, which should be the Alpha and Omega, the beginning and end of life.

Part I. Of Matter And Its Mechanical Properties

PAGE.

LECTURE I. Introduction; the objects and advantages of Science, - 9 " II. Of abstract Science. Departments of Natural Philoso-

phy. Properties of Matter, ------- 14

" III. Inertia. Attraction and Repulsion. Different kinds of

Attraction, -----21

« IV. Gravity, 25

" V. Center of Gravity, 32

" VI. Motion and Force. Laws of Motion, 40

" VII. Compound Motion. Composition and Resolution of Forces, 50

« VIII. Accelerated and Retarded Motion, 56

" IX. Curvilinear Motion. Projectiles, --------61

PART II. ;ti

JRE X.

a

XI.

a

XII.

u

XIII.

XIV.

XV.

u

XVI.

it

XVII

OF THE MECHANICAL POWERS.

Machines. The Cord. The Lever, -.-.-. 69 The Lever continued, ----------73

The Inclined Plane, - 80

The Pulley, ----- 83

The Wheel and Axle, The Wedge. The Screw, - 86 Friction. Moving Powers. General Remarks upon

Machinery, ----- - 93

Locomotion^ 104

1*

VI

CONTENTS.

LECTURE XVIII.

XIX.

XX.

XXI.

Part III. Hydrostatics

PAGE.

Mechanical Properties of Liquids, - - - - - 109

Specific Gravity, ---------- 122

Liquids in Motion, or Hydraulics, ----- 129

LECTURE XXII.

XXIII.

XXIV.

it

XXV.

u

XXVI.

tt

XXVII.

Part IV. Pneumatics

jEriform Bodies. Atmosphere. The Air-pump, - 132 Properties of Air, ---------- 138

The Condensation of Air. Condensing Syringe.

Artificial Fountains. Air-Gun. Diving-Bell, 144 Barometer. Effect of Heat upon Air, - - - - 149 Winds — Their Causes and Effects, ----- 155 Meteorology. Steam. Elastic Force of Steam.

" XXVIII. Atmospheric Pressure upon Water. Pumps. Syphons, 165

Part V. Acoustics

LECTURE XXIX. Sonorous Bodies. Bells. Musical Strings. ^Eolian

Harp, 170

" XXX. Medium of Sound. The Ear. Echo. Speaking

Trumpet. Velocity of Sound. Music. The Human Voice, ---------- 175

LECTURE XXXI

XXXIII.

XXXIV.

Part VI. Optics

Light. Definitions. Motion of Light. Its Intensity. Of Reflection and Refraction, - - - 186 XXXII. Reflection from Mirrors. Plane Mirrors. Convex

Mirrors. Concave Mirrors, - - - - - - 191

Refraction of Light, - - 205

LECTURE XXXV.

XXXVI.

XXXVII.

CONTENTS. Vii

FAOl.

Visual Angle. Fore- Shortening. Perspective. Intensity of Light and Shade. Convergence of the Optic Axes, 222

Duration of Impressions upon the Eye. Single Vision. Imperfection of Vision. Optical Instruments. Shadow, --------231

Nature of Light. Decomposition of Light. Dispersion of Light. Rain-bow. Absorption of Light, 243

Part VII. Electricity And Magnetism

LECTURE XXXVIII. Theories of Electricity. Mode of obtaining it. Conductors and Non-conductors. Atmospheric Electricity, -------- 252

« XXXIX. Magnetism. Dip of the Magnet. Deviation of

the Compass. Theory of Magnetism. The Compass, -- --------- 265

Part VIII. Celestial Mechanics, Or Astronomy

LECTURE XL. Introductory Remarks. Armillary Sphere. The Solar System. Planets. Comets. Application of Mechanical Laws to Planetary Motion, - - - - 273 " XLI. Fixed Stars. Constellations. Galaxy. Nebula?. Con-

Note. — The matter in small type may be omitted by younger pupils, or at the first going over with the work, as also at public examinations.

FAMILIAR LECTURES

ON

NATURAL PHILOSOPHY.

Part I. Of Matter And Its Mechanical Properties

LECTURE I.