c. 
 
 
 UNIVERSITY OF CALIFORNIA. 
 
 FROM THE LIBRARY OF 
 
 DR. JOSEPH LECONTE. 
 
 GIFT OF MRS. LECONTE. 
 No. 
 
/ r <J> 
 
OUTLINES 
 
 OP 
 
 A SYSTEM 
 
 OP 
 
 MECHANICAL PHILOSOPHY 
 
 BEING A 
 
 RESEARCH INTO THE LAWS OF FORCE. 
 
 SAMUEL ELLIOTT COUES. 
 
 " That which we call gravitation and fancy ultimate, is but one fork of a mightier 
 stream for which, as yet, we have no name." 
 
 BOSTON: 
 
 CHARLES C. LITTLE AND JAMES BROWN. 
 1851. 
 
Entered according to Act of Congress, in the year 1851, by CHARLES C. 
 LITTLE AND JAMES BROWN, in the Clerk's Office of the District Court of the 
 District of Massachusetts. 
 
 CAMBRIDGE: 
 
 PRINTED BY BOLLES AND HOUGHTON. 
 
TO THE 
 
 REV. ANDREW P. PEABODY. 
 
 MY DEAR SIR! 
 
 When I first mentioned that I had undertaken a Research 
 into the Laws of Force, you encouraged me to follow up the 
 investigation ; and from that time you have constantly extended 
 to me your sympathy, and have manifested a kind interest in 
 the result of my labors. Thus you are intimately associated 
 in my mind with the work, though it is but just to say that you 
 are in no sense responsible for the correctness of any of my 
 deductions. I dedicate the book to you as an acknowledgment 
 of your kindness, and as a manifestation of my respect for 
 the power of mind which has not only given you your eminent 
 position in your profession, but is conspicuous in every depart- 
 ment of learning to which your attention has been directed. 
 With sincere regard, 
 
 Your friend, 
 
 SAMUEL E. COUES. 
 
 
ERRATA. 
 
 Page 107, line 30th read, descends to a lower level. 
 " 163, line 8th for bury, read buoy. 
 11 258, line 4th for their, read these. 
 " 263, line 2d for common, read coming. 
 u 272, note omit the quotation marks in the second paragraph. 
 " 280, line 5th insert the before work next line, omit the before law. 
 
CONTENTS 
 
 INTRODUCTION. 
 
 CHAPTER I. 
 GENERAL PROPOSITIONS RELATING TO FORCE AND MOTION. . 4 
 
 CHAPTER II. 
 
 PLANETARY MOVEMENTS. FORCE FROM THE FALL or BODIES. HEAT. 
 LIGHT. ELECTRICITY. GALVANISM. MAGNETISM. ANIMAL FORCE. 
 IDENTITY OF FORCE. . . . .- . ' 17 
 
 CHAPTER III. 
 
 CAPILLARY ATTRACTION. ELASTICITY. COHESION. FRICTION. 
 SEPARATION OF COHESION. CEMENTS. CHEMICAL AFFINITY. 44 
 
 CHAPTER IV. 
 
 ACTION AND REACTION. REACTION AS A PROPELLING POWER. 
 Yis INERTIA, MECHANICAL POWERS. CENTRIFUGAL FORCE. 60 
 
 CHAPTER V. 
 
 OSCILLATION. MOVEMENT OF THE WAVES. WHIRLPOOLS AND 
 WHIRLWINDS. VORTICAL MOVEMENT. OSCILLATION OF THE 
 SURFACE OF THE EARTH. GEOLOGICAL EPOCH. FORCE OF DE- 
 SCENT. . 85 
 
VI CONTENTS. 
 
 CHAPTER VI. 
 
 ATMOSPHERIC DENSITY. GRAVITATION OP THE ATMOSPHERE. 
 ELASTICITY OF AIR. ACTION OF THE BAROMETER. THE BAR- 
 OMETER THE DIRECT MEASURE OF ALTITUDE. . . .113 
 
 CHAPTER VII. 
 PRESSURE OF FLUIDS. . . 151 
 
 CHAPTER VIII. 
 
 PRESSURE OF ELUIDS, CONTINUED. GRAVITATION OF FLUIDS. CO- 
 NICAL ADJUTAGES. RELATIVE LEVELS OF AIR AND WATER. 
 
 178 
 
 CHAPTER IX. 
 THE TIDES. . ,. ^ ^." 225 
 
 CHAPTER X. 
 
 TRADE WINDS. OCEANIC CURRENTS. ERRATIC DRIFT. METEOR- 
 OLOGY. . . . . . . . ... 253 
 
 CHAPTER XL 
 THE MATHEMATICAL ARGUMENT FOR GRAVITATION. . . 284 
 
 CHAPTER XII. 
 
 LAW OF THE VELOCITY OF FALLING BODIES. ORIGIN OF THE THE- 
 ORY OF GRAVITATION. MOVEMENTS OF THE SPHERES. HARMONY 
 OF SCIENCE WITH REVELATION. . . . .'' 308 
 
INTRODUCTION. 
 
 THESE outlines of a System of Mechanical Philosophy 
 are the result of a research made by the author, for his own 
 instruction. In the research he attempted to separate sup- 
 position from fact, the questionable from those things 
 necessarily taken for truth by the laws of the mind. The 
 inquiry took the form of snythetical reasoning, proceeding 
 step by step, deducing the unknown from what appeared 
 self-evident, taking nothing as truth on authority, however 
 great the name which had given currency to the theory ; 
 thus shutting out all sources of error except such as resulted 
 from the weakness of the individual mind. Arriving by 
 this process at conclusions, the very opposite of those taught 
 in the schools of science, these conclusions were tested by 
 an appeal to the phenomena of nature. Both, the reasoning 
 without the phenomena, and the phenomena without the 
 reasoning, pointed to the same general truths. 
 
 Thus are presented opinions which appear to be sup- 
 ported both by reason and by observation, and presented 
 in the order of their development. The writer feels con- 
 fident, that, however defective may be his logic, however 
 imperfect may be his statement of the facts of science, 
 however crude may be his application of the truth to the 
 i 
 
2 INTRODUCTION. 
 
 explanation of phenomena, he has unfolded some principles, 
 which, when distinctly evolved from mingled error, will 
 change somewhat the basis on which mechanical philosophy 
 now rests. 
 
 But, whether or not the opinions here presented are 
 demonstrated to the minds of scientific men, it is admitted 
 that many of the present explanations of philosophy are 
 received as the supposed best possible explanations, rather 
 than as settled truth, on which the mind confidently reposes. 
 The conservatives in science may be successful in pointing 
 out the errors of new theories, but they have other more 
 difficult work, that of the defence of the old theories. 
 
 A reexamination of principles supposed to be forever set- 
 tled by the authority of a Newton may strike many minds 
 as presumptuous. It will be seen, however, that the splen- 
 did conceptions of Kepler, made distinct and thoroughly 
 demonstrated by Newton, are not assailed. The glorious 
 truth of the harmony of the movements of the spheres, by 
 which the astronomer can track out the orbit of the most 
 eccentric wanderer of the heavens, stands forever, the reflex 
 of the light of creation from the minds of the truly great. 
 
 It is the school which now determines opinions on philo- 
 sophical subjects. Men are taught to believe rather than to 
 reflect, to receive opinions rather than to evolve them by 
 the process of intense thought. A scientific education is a 
 capital, the value of which is impaired by dissent. It would 
 seem as if nothing further could be attained, as if philosophy 
 had soared its highest flight ; for theories thus pass from 
 mind to mind, from generation to generation, as settled 
 truths, and theories too, somewhat questioned or indistinctly 
 comprehended, even by those who teach them. 
 
 To induce reflection, therefore, upon admitted theories, 
 
INTRODUCTION. 3 
 
 cannot fail to do some service to the cause of truth ; for, as 
 it has been observed, " nothing tends more to the corrup- 
 tion of science than to suffer it to stagnate. The waters 
 must be troubled before they can exert their healing virtues. 
 A man who works beyond the surface of things, though he 
 may be wrong himself, yet clears the way for others, and 
 may chance to make his errors subservient to the cause of 
 truth." 
 
 This work is not intended as an elaborate philosophical 
 treatise, but as a rapid outline ; and only those consider- 
 ations are presented which are necessary to develop the 
 opinions advanced. Much collected material has been 
 laid aside for future use, if it be thought that the opinions 
 set forth are worthy of additional attention. 
 
 PORTSMOUTH, N.H., Sept. 7, 1850. 
 
CHAPTER I. 
 
 " FOR SINCE THE HUMAN MIND PARTICIPATES AS IT MAY IN THE 
 FRUITFULNESS OF THE CREATIVE NATURE, IT DOTH FOR ITSELF 
 BRING FORTH REASONABLE THOUGHTS." 
 
 IN all investigations of matter and force, we must divest 
 them of all properties that are boundless, that are without 
 fixed limits, determinate degrees. Thus, matter is not infi- 
 nite in its extent nor in its capacity for motion ; so of force, 
 its action is not infinite ; it has parts, or divisions, each 
 with a fixed rate of power, and as a whole, its aggregate 
 power is fixed, meted out by Him by whose infinite power 
 it was constituted. We need recurrence to this as the 
 point of departure in our course, as that to which we can 
 recur as something fixed, when the ocean on which we 
 speed our way has no guide for our path over its vastness. 
 There is one God, the ultimate Cause of all things, of whom 
 alone can infinity of attributes be affirmed. This truth is 
 here presented, not for its religious bearing, but from the 
 necessity of recurring to it in its relations to the first prin- 
 ciples of philosophy. The admission that His attributes 
 alone are infinite in degree, is essential to distinctness of 
 opinion with regard to matter and force. The human mind 
 cannot comprehend infinity; any proposition, therefore, 
 which involves the boundless, is unintelligible ; decide it 
 affirmatively or negatively, the mind feels no confidence in 
 the result. 
 
OUTLINES, ETC. 5 
 
 1. Matter has inertness as an essential property ; it has 
 substance and extension ; it exists in atoms or ultimate par- 
 ticles, indestructible and impenetrable, between which atoms 
 there is space ; these atoms aggregated, constitute masses, 
 between which there is space ; these masses constitute 
 worlds, between which there is space. Space is room or 
 freedom for motion, or that in which matter exists and is 
 moved. Motion is the act of the change of place of mat- 
 ter ; it is the passing of matter from one part of space to 
 another. No atom of matter can occupy the same place with 
 another atom. Force is that which produces the motion of 
 matter, or that which causes matter to act. Force cannot 
 act where it is not. 
 
 These definitions are the usual, commonly received defini- 
 tions of matter and force, and the resultant motion. We 
 express in them all that can be known. An inquiry into 
 their nature or construction embraces the element of the 
 infinity of God who created them, and " plunges us at once 
 into that deep which never yet was fathomed by human 
 intellect." Newton thus speaks of matter. " We believe 
 that God in the beginning formed matter in solid, hard, 
 massy, impenetrable, movable particles, of such sizes, fig- 
 ures, and other properties, and in such proportion to space, 
 as most conduced to the end for which He formed them ; 
 and that these primitive particles being solids, are incom- 
 parably harder than any porous bodies compounded of them, 
 even so very hard as never to wear or to break to pieces ; 
 no ordinary power being able to divide what God himself 
 made one at the first creation." 
 
 2. That which is moved and that which moves it, are not 
 identical, not the same thing ; the one, matter, having in- 
 
6 OUTLINES OF A SYSTEM OF 
 
 ertness as an essential property ; the other, force, having 
 as an essential property power to give motion. Wherever 
 matter is, there is inertness ; wherever force is, there is 
 motion. 
 
 The belief of the separate and independent existence of 
 cause and effect results from the constitution of the mind. 
 It is what God compels us to believe. It is as inspiration. 
 We think of God as existing separate from his creation, 
 of our minds as separate from thought and perception ; and 
 so of force, as an independent power, as in no sense matter, 
 but as that which gives motion to matter, as that which 
 causes matter to change its place. This separate existence 
 is recognized in the three great laws of motion, which refer 
 to force as the cause of motion. 
 
 These words of Herschell very distinctly present the 
 idea : " Force may be communicated to inanimate matter, 
 it may be concentrated in the same mass by continuation of 
 animal or muscular force. We thus learn to regard motion 
 in matter as the effect and indication of force, and force 
 may be defined as that which is capable of producing motion 
 in matter, or of stopping and altering its direction when 
 produced." Daniell (Introduction to Chemical Philosophy) 
 says, " A body at rest would remain quiescent unless it were 
 to receive an impulse from without," or objectively, and thus 
 philosophy recognizes the inertness of matter. Growing 
 from this idea is the doctrine of vis inertise. It is a term 
 expressive only of the fact, that matter rests when unmoved, 
 and moves when not at rest, and that time often elapses 
 after the impulse, before motion is apparent. Strictly it 
 asserts the impossibility of self-moving matter. 
 
 3. Matter which is in motion must continue in a state of 
 
MECHANICAL PHILOSOPHY. 7 
 
 uniform motion forever, unless disturbed by the action of an 
 external cause. 
 
 The same cause produces the same effects. This propo- 
 sition, so far as it goes, is identical with the first of the three 
 great laws of motion, which is, " A body must continue for- 
 ever in a state of rest or of uniform motion, in a straight 
 line, if not disturbed by the action of an external cause." 
 If this be true of bodies both at rest and in motion, the pro- 
 position is true as regards bodies in motion, and as true when 
 considered apart from the direction of the motion as it is 
 when the law defines the line of motion. 
 
 4. All motion is in proportion to the force which pro- 
 duces it. 
 
 The degree of the effect is in proportion to the cause ; 
 in other words, add to or take from the force in action upon 
 given matter, the quantity of motion is changed propor- 
 tionally. The second of the three laws is : " Every change 
 of motion produced by the external (objective) cause is 
 proportional to the force impressed, and in the direction of a 
 straight line in which the force acts." The proposition 
 affirms the first clause of the law, and this is necessarily 
 true independently of the truth of the latter clause. 
 
 We draw from this proposition the following as corrolla- 
 ries : 1st, that force is divisible, different quantities or degrees 
 of it acting at different times on the same matter ; 2d, force 
 is transferable, for otherwise, that is, without transfer of 
 force, there could be no increase or diminution of motion. 
 
 5. The absolute condition of the transfer of force is its 
 presence with matter not susceptible of motion by it. 
 
 The essential property of force being action, wherever it 
 
8 OUTLINES OF A SYSTEM OF 
 
 is, it acts, or from its nature it is transferred from matter 
 which cannot be moved to matter having- space for motion. 
 
 6. The degree or velocity of the motion of a mass de- 
 pends on the degree of force which acts upon each atom 
 constituting the moving mass. It appears self-evident, that 
 every atom, perhaps in a degree according to its element or 
 kind, requires always the same force to move it with the 
 same velocity, and the motion of the mass depends on the 
 degree of force relative to the number of its atoms. 
 
 7. Every atom of the solar system is in continued motion, 
 orbital and rotary. 
 
 Hence it follows, that it is force which determines the 
 position of every atom, mass, and world, and determines 
 their position positively in space. It also determines the 
 relative position of all things. 
 
 8. Matter occupies but one place in space at the same 
 time, and consequently no atom can have motion but in one 
 line of direction at the same time. 
 
 Hence it follows, that all motion is orbital, rotary, 
 -curvilinear ; for, all atoms being in curvilinear motion, no 
 addition of rectilinear motion can change the curve into the 
 straight line, there will ever remain the element of the 
 curve. The contrary opinion indicates infinity, and is un- 
 intelligible. The foundation principle of geometry is the 
 measure of all angles by arcs of the circle, and the meas- 
 urement of the circle or curve conversely by the inscribed 
 straight lines or angles. 
 
 Hence the fixed relation between the diameter of the 
 circle and its circumference, and the measure of motion by 
 
MECHANICAL PHILOSOPHY. 9 
 
 the diameter of the circular orbit. We assume that the 
 harmonic motion of the heavenly bodies bears a certain pro- 
 portion to the orbit, that this velocity has a fixed ratio to 
 the diameter, and that this ratio mathematically determined 
 is proportional to the square of the distance of the circum- 
 ference from the centre. 
 
 The velocity of bodies moving in free space being in a 
 fixed ratio to the orbit, it is the present force, the* active 
 principle, which determines the orbit. A change of the 
 degree of force would enlarge or diminish the orbit. In 
 all free motion, therefore, the motion is uniform and har- 
 monic. Two atoms moving in the same orbit will move with 
 the same velocity ; in different orbits will preserve that rela- 
 tive position which is determined by the difference of orbit, 
 and the difference of the line of direction ; so that mathe- 
 matically the relative position of any body can be deduced, 
 given as the elements of calculation its orbit and direction 
 of motion. 
 
 9. Rectilinear motion, or motion in a straight line, cannot 
 be affirmed of any atom belonging to or in harmony with 
 the solar system, or with the system of worlds. The hori- 
 zontal line on the surface of the globe is curvilinear. So 
 from any one point to another, in, on, and about the earth, 
 the moving body takes the curved line. In the old philo- 
 sophy, circular motion was deemed the natural motion ; but 
 the new philosophy conceives of circular motion as con- 
 strained by the operation of conflicting forces. 
 
 10. The supposed perpendicular descent of a falling body 
 is a curvilinear motion. This is not practically admitted, 
 but mathematically deduced ; the fall is termed a " cubical 
 
10 OUTLINES OF A SYSTEM OF 
 
 parabola." The supposed attraction of the earth does not 
 draw in straight lines, falling bodies preserving ever their 
 rotary motion. 
 
 11. Bodies in rotation with the earth, on receiving addi- 
 tional force, must either take a higher level of rotation, 
 or use the force received in additional motion in a new 
 direction. 
 
 12. In the act of falling whereby a lower level of rota- 
 tion is assumed, force must be transferred from the falling 
 body when its motion is suspended. 
 
 The motion of falling is added to the rotary motion, 
 thereby giving action to the present force. This motion 
 being suspended, only rotary motion in a smaller orbit 
 remaining, force will be transferred. Hence arises spare 
 force of descent. The spare force of descent will be mea- 
 sured by the degree of descent. Hence the spare force of 
 falling bodies is measured by the square of the time of 
 descent, equal times giving equal distances of descent. 
 Thus most distinctly is presented the law of falling bodies, 
 or motion begetting motion, which, indistinctly understood, 
 caused the great controversy between the schools of Des 
 Cartes and Leibnitz, and which to this day has obscured 
 mechanical science, by making the occasional abnormal 
 motion of falling bodies the element of calculation of har- 
 monic motion. 
 
 13. The motion of the heavenly bodies being harmonic 
 with fixed velocity according to orbit, their velocity is the 
 immediate measure of the velocities of retarded or accele- 
 rated motion ; that is, the abnormal motion is detected and 
 
MECHANICAL PHILOSOPHY. 11 
 
 measured by the normal, the motion of bodies in confined 
 space being determined by the velocity of bodies in free 
 space. 
 
 Time is the indirect measure of velocity ; the motion of 
 the earth which measures time, the direct measure of velo- 
 city. Hence all velocity is known by and measured by the 
 rotation of the earth. A body which moves thirty miles in 
 one hour moves over the given space isochronously, or 
 while the earth has moved one twenty-fourth part of her 
 rotary circle. Time, therefore, has no reference to force 
 and motion so as to increase or diminish them, and motion 
 refers to time only as indicating the extent of the motion of 
 the earth. 
 
 14. There is beside the consentaneous motion of the 
 atoms of the mass, or the progressive motion of the mass, 
 an atomic or molecular motion of every atom composing the 
 mass. 
 
 This proposition will receive its most perfect demonstra- 
 tion by the facts and phenomena of nature ; but is believed 
 from analogy, that the same law governs the minute as 
 well as the extended, also from the fact that there is- 
 space between all atoms, that force is primarily in action on 
 the atoms. If force be present with atoms, and there be 
 space for motion, motion is affirmed. We leave this propo*- 
 sition mainly upon these general statements, recurring, ia 
 this place, to one most significant fact : " The expansion of 
 volume of small bodies by dilatation from heat, may be ob* 
 tained without sensible error by trebling the number which 
 expresses its increase in length." Daniell's Introduc- 
 tion to Chemical Philosophy. The trebling of the diameter, 
 it will be perceived, gives nearly the circumference of the* 
 circle of motion. 
 
12 OUTLINES OF A SYSTEM OF 
 
 15. Force transfers itself from atom to atom without ap- 
 preciable time. Time being measured by the action of force 
 upon a given quantity of matter, the transfer of force with- 
 out matter is therefore without time ; or with a reduction 
 of the matter, velocity is increased ; annihilate the matter, 
 and time is no longer to be affirmed of its passage. Thus 
 attraction of gravitation is spoken of " as a force which is 
 transmitted instantaneously," and so of light, heat, gal- 
 vanism, &c. So far as they pass in appreciable time it is 
 because they (the forces which move) are connected with the 
 material ; the essential quality of pure force unembodied 
 
 is change of place without appreciable time. 
 
 ' 
 
 36. Force is diffusible only by contact of the moving 
 atom with another atom. This appears from the fact that 
 force is transferable only when it cannot induce motion, and 
 while space remains there is room for motion. Therefore, 
 the motion of a body must be after a lapse of appreciable 
 time from the contact of the atoms. Consentaneous motion 
 of the mass is from the equal diffusion of motion through its 
 particles. These particles have room for motion before 
 impingement ; therefore, the mass moves in appreciable 
 time from the contact of the atoms. 
 
 This is finely illustrated by a row of suspended ivory 
 balls through which force is communicated in appreciable 
 time by the measured motion of the balls, according to their 
 distance and the degree of force. It is the foundation of 
 the doctrine of vis inertiae. It is not impossible that the 
 distance of atoms constituting a mass may be relatively 
 determined with regard to the distance of atoms in another 
 mass. It will be found that, the more porous the body, the 
 longer is the lapse of time between the impingement and the 
 
MECHANICAL PHILOSOPHY. 13 
 
 motion of the atoms as the mass ; we instance equal weights 
 of atmospheric air and of lead. The force is communicated 
 instantly, motion results instantaneously, but time is predi- 
 cable of the passage of atom to atom, to diffuse the motion 
 equally that it may be consentaneous. 
 
 17. Force acts independently of direction ; on its trans- 
 fer, its former line of motion does not necessarily imply a con- 
 tinuance of the same line of motion. A body in motion 
 must continue forever in a state of uniform motion, unless 
 disturbed by the action of an objective cause. The force 
 will be transferred upon impact, and the body receiving it 
 will move in the direction in which it is free to move ; or, if 
 the body which obstructs motion be not movable, the force, 
 not being transferred, acts in the opposite direction. 
 
 The resultant motion of impinging bodies is demonstrated 
 by the mathematical figure, the " polygon of force," and is 
 equally demonstrable by the diagram showing the contact of 
 atoms having surface ; so, too, the angle of incidence and 
 reflection, when a body impinges upon an immovable 
 mass, shows that the resultant motion is determined only 
 by the free space for motion. If two flat surfaces meet, 
 they can be separated only in the opposite direction, if the 
 separating force acts equally on the surface. And so 
 through more complex movements. 
 
 We refer to facts of common observation ; the rotary 
 motion of the windmill by the horizontal impingement of the 
 wind, the billiard ball, the rise of the wave. On this 
 action of force, independent of direction, depends the appli- 
 cation of force in mechanical combinations, by which the 
 force of falling water is conveyed anywhere, and acts in any 
 direction. Force does not act where it is not ; but the me- 
 
 2 
 
14 OUTLINES OF A SYSTEM OF 
 
 chanic, availing himself of the laws which govern its trans- 
 fer, leads it to the loom and opens for it the desired line of 
 motion only. 
 
 This doctrine of the transfer of force is one of the found- 
 ations of the supposed action and reaction of force ; every 
 instance of reaction can be directly traced to the transfer 
 of force. 
 
 18. Transfer of force, which does not give the body to 
 which it is transferred consentaneous motion of its atoms, 
 gives vibratory motion to the parts of the mass, or increase 
 of molecular motion, the motion induced being of the same 
 degree as the motion that was suspended. The force being 
 transferred, and motion being in proportion to the force, the 
 vibratory or molecular motion must be the same ; or, if the 
 motion of the recipient of the force be retarded, an equal 
 quantity of its force is also turned from the consentaneous 
 motion, so that the resultant motion, internal to the mass, 
 will be doubled ; that is, the internal motion is the aggre- 
 gate of the suspended motion of both impinging masses. 
 Thus, the motion of the tongue of the bell, and of the bell, 
 jointly increase the loudness of its tone ; and other instances 
 of this result present themselves to every mind. Hence the 
 concussion and destruction of two balls in opposite motion, 
 which would not result from the motion of either upon the 
 other at rest. 
 
 Vibratory motion being the unequal or rather unconsen- 
 taneous motion of the parts of a mass, if there be not a 
 gradual increment of motion from the surface to the centre, 
 there will be nodes or points of rest. Thus musical chords 
 manifest certain points of rest. 
 
 Vibratory motion being determined by the degree of force, 
 
MECHANICAL PHILOSOPHY. 15 
 
 if the same quantity of matter be moved the same distance, 
 the times of vibration will be the same ; if the distance be 
 diminished, there will be an increase of velocity. Tone being 
 dependent on time of vibration, an increase or diminution of 
 force changes the range, preserving the tone. Isochronous 
 vibration is, therefore, a branch of the law which induces the 
 same quantity of motion by the same quantity of force. It 
 follows, too, that there can be no vibratory or reciprocal 
 motion in free space. 
 
 19. Force is indestructible. This appears from the gen- 
 eral consideration, that what God formed at the beginning 
 no power can destroy. It is imperishable, too, as is evident 
 from its transfer from atom to atom and from mass to mass, 
 and from the state of equable motion, which bodies actuated 
 by a given degree retain. It is also one and identical. 
 That which gives motion is force ; if it have different essen- 
 tial properties, these properties cannot be detected, as force 
 is known only by the motion it gives to matter. 
 
 There are not differing qualities or kinds of force, which 
 give, this kind, circular motion to bodies, this kind, a 
 straight motion, this kind, motion in a contrary direc- 
 tion ; nor is there a planetary force, and a molecular force, 
 and an oscillatory force, and a directly acting force ; but 
 the one force may act on any element of matter, moving it 
 in any direction, which idea will receive further illustration 
 in the following chapter. 
 
 In the research made, the general propositions were ex- 
 tended much further ; but up to this point only were they 
 carried with that distinctness which should characterize 
 such propositions. Others remain therefore for further 
 examination. 
 
16 MECHANICAL PHILOSOPHY. 
 
 It will be observed, that an inquiry like the preceding 
 has reference to force mainly as in action, giving to mat- 
 ter place, position, and motion in reference to space, 
 actual, and not apparent or relative motion. We try to 
 consider relative motion only as indicative of true motion, 
 and this as indicative of the laws of force. Thus the ascent 
 of water in the capillary tube is regarded, not as motion in 
 relation to the tube so much as a new rotatory orbit of the 
 elevated water. The log line which is veered from the ship 
 has apparent motion of its own, but the actual motion is that 
 of the ship. This distinction we would recall to the mind 
 of the general reader. 
 
CHAPTER II. 
 
 "WHEN WE HAVE THE DECREES OF NATURE, AUTHORITY GOES FOR 
 NOTHING." Galileo. 
 
 THE errors of mechanical philosophy, if there are errors, 
 arise from the assumption of gravitation, or the attractive 
 power of matter ; from the application of the law of the 
 motion of falling bodies, to the uniform motion of bodies 
 remaining in one determined orbit ; from the belief that 
 rectilinear motion is the natural motion, and that the cur- 
 vilinear is a constrained motion induced by conflicting 
 forces ; and from keeping out of sight the intense motion of 
 every atom in its rotation and revolution with the earth, 
 which, from its greater comparative velocity supplies the 
 governing or controlling motion, and by reference to which 
 alone, incidental, retarded, or accelerated motion, is to be 
 understood or to be explained. 
 
 In the illustration of our views we shall follow no artificial 
 arrangement, but present our thoughts in the order in which 
 they occurred from the natural connection of one class of 
 facts with another class of facts, as this will throw more 
 light on the peculiar views than any predetermined order of 
 investigation. 
 
 Our first attempt is to illustrate the idea of the identity 
 of force, to prove that the motive power of nature is one, 
 acting under uniform laws ; that force, whether it form the 
 
 2* 
 
18 OUTLINES OF A SYSTEM OF 
 
 dew-drop or marshal the "hosts of heaven," whether it 
 manifest itself in the flow of the tides or of the purple stream 
 of life, whether in the flash of lightning, or in the sweep of 
 the bird with motionless wing, is ever the same principle ; 
 that its divisions and subdivisions, its ever-varying names 
 in science have obscured the law of its action, and thrown 
 a mist over philosophy else apparent, from the ever-changing 
 and conflicting theories. 
 
 Of the nature of force as well as of the matter it moves, 
 as we have said, we are entirely ignorant, and from the 
 constitution of the -mind we shall forever remain ignorant. 
 But the laws of its action given to it from the beginning, 
 and ever enduring, may perhaps be distinctly traced out 
 and understood. Thus, the force which moves the spheres 
 acts under the intelligible law, that velocity is in proportion 
 to the area of the orbit, that with the diminution of distance 
 from the centre velocity increases, with the increase of dis- 
 tance velocity diminishes ; so that all bodies revolving in 
 free space describe equal areas in equal times. This is a 
 property of orbitual revolution, in other words, it is the 
 property of force. It is a fixed law, subject to no change. 
 Aberrations and perturbations are temporary and oscilla- 
 tory ; the mean time of revolution never changes. 
 
 The revolution of the heavenly bodies is accompanied 
 by rotation on their axis. This connection of the primary 
 with the secondary movement arises from another law of 
 force, from another property of the power which imparts 
 motion. The two movements appear to have an opposite 
 character. In the one, as we have seen, velocity in- 
 creases by the diminution of the orbit ; in the other, velo- 
 city becomes lessened as the rotating matter approaches the 
 centre of rotation. How slow the rotation of the central 
 
MECHANICAL PHILOSOPHY. 19 
 
 parts of the earth, while at the equator the velocity of the 
 surface is more than one thousand miles an hour ! 
 
 From the nature of the rotating sphere there is one fixed 
 ratio of increase of the velocity of its parts. Given the 
 velocity at any distance from the centre of rotation, the 
 velocity at any other distance can be determined. Its ratio 
 of increase is proportional to the increase of the area of the 
 circle described. We have the same measure of increase 
 outward in rotation, that we have inward in revolution. 
 The primary and secondary movements are under the same 
 general law. Besides, there is also a fixed ratio between the 
 velocities of both movements, for such is the far pervading 
 law of nature. 
 
 If the orbit of any planet were enlarged without additional 
 force of propulsion, it would move, in its new orbit, with de- 
 creased velocity. Its motion would not be harmonic ; it 
 would not describe the equal area of planetary motion. To 
 bring it into harmonic motion it would require additional 
 force, and this additional force needed would be measurable 
 by the increased area of orbit. If, on the other hand, the 
 orbit of any planet were decreased, with the same propelling 
 force its velocity would be increased, and it would be out of 
 harmony with its associated worlds. With equal velo- 
 city it must part with, or transfer, a portion of its force. 
 This degree of spare force would also be measurable by the 
 reduction of the area of the orbit. The degree of force 
 required or imparted is not measured by the increase or dim- 
 inution of the circumference. The orbit does not measure 
 velocity. It is a path of motion, continuous, without be- 
 ginning or end. By a fixed law, the required force is 
 determined by the area described, which increases and 
 diminishes in a higher ratio than the length of the circum- 
 
20 OUTLINES OF A SYSTEM OF 
 
 ference which encloses the area. Thus, by the enlargement 
 of a planet's orbit, it would need added force to preserve the 
 harmony of planetary motion, and by its diminution it would 
 impart force, and the force added, or given up, would be 
 measurable by the change of area. In the words of Her- 
 schell : " The law of the areas determines the actual velo- 
 city of the revolving body at every point, or the space really 
 run over by it in any given portion of time.' 7 If the velocity 
 be thus determined, so is the present force which determines 
 the velocity. 
 
 This is equally true of the velocity and force of rotation. 
 If a mass at the surface of the earth be elevated, it gains 
 thereby a superior level of rotation ; its orbit is enlarged, 
 it requires additional force. If the mass fall, thereby 
 decreasing its orbit of rotation, it has the spare force of 
 descent ; it requires less for rotation, and the falling body 
 imparts force. The force received for elevation, the force 
 given out by depression, is measured in one case by the 
 increase, in the other by the decrease, of the area of the 
 circle of rotation. Though in one view it appears as if 
 there were the converse action of force, yet the general 
 kw is apparent, of the increase and diminution of required 
 force for any area of orbit, whether acting outwardly from 
 the centre or inwardly to the centre of revolution. 
 
 The identity of force, acting in the primary movement of 
 the spheres, and in the secondary movement, is apparent, 
 thus considered, and a general, far-reaching law is most 
 clearly indicated. 
 
 The force which moves the different parts of the earth in 
 rotation differs much in intensity. How small, compara- 
 tively, in the central masses at the axis of rotation ; how 
 great, on the surface of the earth at the equator ; how 
 
MECHANICAL PHILOSOPHY. 21 
 
 different the force moving the surface of the earth at the 
 equator from the force moving the surface of the earth at 
 the poles ! Yet, the weight of falling bodies, or their spare 
 force of descent is nearly the same at the equator that it is 
 at the poles. 
 
 The spare force of descent is most unquestionably greater 
 for an equal change of orbit at the equator than at the poles ; 
 but the change of the area of the orbit is far less by the 
 descent of one foot at the equator than it is at a distance 
 from the equator. As we go from the equator the force 
 of rotation lessens, the area of the orbit lessens 4n that 
 ratio by every foot of descent, so that the increased ratio of 
 the decrease of area compensates for the decreased force of 
 rotation. Thus have we an equal " spare force" of descent 
 on the same parallel of latitude, slightly increasing as we go 
 from the equator, as by the spheroidal form of the earth 
 the decrease of the area is more rapid by equal decreases of 
 diameter, in proportion as the earth changes from the perfect 
 sphere to the oblate spheroid. 
 
 There is not, then, one law of force for the revolution of 
 the spheres, and another for their rotation, and another for 
 the changes of level of the masses composing the spheres ; 
 and we think that we can show that the law, by which the 
 spheres and masses are moved, also directs and governs the 
 motion of the atoms composing every mass and sphere. 
 
 The spheres lay spread out before us as distinct objects 
 of conception. From the immense extent of space they 
 occupy, and the almost boundless range of their motion, the 
 law of force indicated by them becomes intelligible, and is the 
 object of precise reasoning and of mathematical calculation. 
 If we would understand the minute, we must throw upon it 
 the light gained from the extended. " There is a certain 
 
22 OUTLINES OF A SYSTEM OF 
 
 character or style, if I may use the expression, in the opera- 
 tions of Divine Wisdom ; something which everywhere an- 
 nounces amidst an infinite variety of detail, an inimitable 
 unity and harmony of design, in the perception of which 
 philosophical sagacity seems chiefly to exist ; " or, as New- 
 ton expressed the same idea, " Nature will be very con- 
 formable to herself, and very simple." Thus, no less 
 exact, no less fixed by determinate law is the motion of 
 atoms, and, in the examination of the minute, this idea of the 
 extent and universality of primary laws should be ever 
 present to the mind. 
 
 How unlike the simplicity of nature, her directness of ac- 
 tion, the far-reaching nature of her laws, is the array of op- 
 posing and conflicting forces, by the clashing of which we are 
 taught that the balance or equilibrium of things is preserved ! 
 To return for a moment to the spheres, - there is the im- 
 pelling force, the repulsive or centrifugal force, the attract- 
 ive or centripetal force. Of what use are these ? " I am 
 persuaded," says Plato, " that if the earth is placed in the 
 middle of the heavens, as they say it is, it stands in no need 
 of air or any other support to prevent its fall ; its own 
 equilibrium will keep it up. For whatever is equally poised 
 cannot incline to either side, and consequently stands firm 
 and immovable, this I am convinced of." If the centripetal 
 and centrifugal forces balance each other, they induce no 
 action ; give the earth the force for harmonic motion accord- 
 ing to her orbit, she needs neither to keep her in the track ; 
 there would be no danger of her flying off in a tangent, or 
 of her falling into the central fires of the sun ; evenly 
 balanced with them, she would be equally balanced without 
 them. 
 
 Why these conflicting forces were created by philosophy 
 
MECHANICAL PHILOSOPHY. 23 
 
 is very apparent. They follow from the strange assumption 
 that nature abhors the orbitual or curvilinear motion ; that, 
 in the words of Herschell, " A straight line, dynamically 
 speaking, is the only path which can be pursued by a body 
 absolutely free, and under the action of no external" cor- 
 rective "force." Centrifugal force is therefore not exactly 
 a force, but the tendency of nature to escape from the con- 
 fined curvilinear motion, and to get back the sphere into the 
 straight line of motion. Philosophy looks upon the myriads 
 of rolling spheres as in unnatural, constrained movement, 
 and there must needs be conflicting forces, to form the 
 grooves and channels which hedge in the planets, and keep 
 them to their orbits, when they would so rejoice in free 
 straight motion to the bounds of space. 
 
 Whewell says that, " In cosmical phenomena, every 
 thing in proportion as it is referred tojpechanical prin- 
 ciples tends to simplicity, to permanent and uniform forces, 
 to one common property. In magnetical and chemical 
 appearances, the application of mechanical principles leads 
 only to a new complexity which requires a new explanation, 
 and this explanation involves changeable and variable forces, 
 gradation and opposition of qualities." That is, plain, 
 simple, mechanical laws apply only to the enlarged action of 
 nature ; in her recesses there is confusion, unintelligibility. 
 For the want, therefore, of fixed general laws in the minor 
 mechanism of nature, or for the lack of comprehension of 
 those laws, the department of " mechanico-chemical " sciences 
 is cut off from general philosophy, and managed by a great 
 array of conflicting forces, such as heterogeneous attraction, 
 homogeneous attraction, capillary attraction, various forms 
 of repulsion, elasticity, cohesion, chemical affinity, current 
 affinity, and the forces of the imponderables. Every judg- 
 
24 OUTLINES OF A SYSTEM OF 
 
 ment in this department is particular. " There is no en- 
 largement of view to general propositions." We see deep 
 thinking, " but the conclusions arrived at, even though 
 clearly expressed, are intricate and obscure." There is 
 not in the teachings of mechanico-chemical science the 
 prominence, the boldness, the exactness; the simplicity, 
 which characterize the works of nature, whether her force 
 be exerted on the atom or on the world. 
 
 Imponderables are so called because they are not the 
 subject of weight. They impart no force by the act of 
 descent, but for this reason they are not proved to be imma- 
 terial, without matter. We read, {London EncyclopcedicC) 
 that " a stream of electric fluid issuing from points, possesses 
 force sufficient to counteract the power of gravitation in 
 light bodies" ; ofcourse the imponderables could counteract 
 the gravity of any matter which was their vehicle, or rather 
 which they moved. Gravity being the unused force of 
 rotation, given out on the arrestation of the motion of the 
 falling body, they have none of this spare force ; they can- 
 not be arrested ; they consume all their inherent force in 
 their rapid flight. It is only by the stopping of the descend- 
 ing motion of falling bodies that they give out force or indi- 
 cate weight. We know not of pure disembodied force, and 
 believe that the imponderables are the combination of force 
 and matter, the force in intense degree compared with the 
 matter ; that the element of matter, and its quantity in the 
 possession of force, makes the distinctive character of the 
 imponderables, and that force is thus fitted for especial func- 
 tions in the economy of nature. This view does no violence 
 to any system of philosophy, and appears demonstrable by 
 the views we have taken in the preceding propositions. 
 
MECHANICAL PHILOSOPHY. 25 
 
 First, of heat. Heat has been regarded as the repulsive 
 force, as the diluent of force, keeping it in due bounds. 
 The same philosophers who would set aside mechanical 
 action with reference to the mechanico-chemical sciences, at 
 the very outset bring back the discharged mechanical laws. 
 They need a pendulum or balance spring, something by 
 which to regulate and control the mixture of forces. Heat 
 is elected to this office of antagonism. The perfect law of 
 force needs not this restraint. But there is a peculiarity of 
 the action of force under the condition of heat, which has- 
 been generally referred not to its nature, but to its con- 
 nected matter. It seems fitted thereby more especially to 
 induce corpuscular motion, and the heat acts plainly and 
 distinctly in giving consentaneous motion to masses ; yet 
 most usually its effects are traced in an internal action. 
 
 We notice in this place the difference between solar and 
 radiant, or reflected heat. The passage of solar heat through 
 a lens shows that force then has under its control matter, 
 the atoms of which have extent of surface, as will be 
 explained when we refer to light. Radiant or reflected 
 heat is not reflected or bent by the passage of its ray& 
 through a glass lens, but is absorbed by the glass, which 
 becomes heated, and continues so until by conduction the 
 heat is equally diffused. It appears, then, as if by the 
 impact it deposited a portion, at least, of its accompanying 
 matter, and, the matter being deposited, the heat in passing, 
 through the lens is absorbed. The force has taken its con- 
 nection with other matter. Radiant heat is then force par- 
 tially divested of its matter ; partially, we say, because in. 
 its passage through a lens of rock salt, it again obeys the 
 law of the passage of light and heat through a transparent 
 media. A secondary radiation of heat still further deprives 
 3 
 
26 OUTLINES OF A SYSTEM OF 
 
 it of its matter. Thus we come to the conclusion that these 
 differences are caused by the deposit of matter at the im- 
 pingement of its rajs. It shakes off, as it were, its imped- 
 ing embodiment, that with unimpaired energy it may give 
 its strength to the corpuscular movements. 
 
 The action of heat is readily explained. Every species 
 of matter has that quantity or degree of force necessary to 
 maintain its atomic structure. This is called latent heat, 
 and is latent force. Now with the normal degree of force 
 in molecular action, another degree of heat or force can 
 be received and made latent in the corpuscular action 
 without apparent change of structure. This is specific 
 heat ; another added quantity becomes sensible or diffusible 
 heat. It is beyond the normal heat which its structure can 
 bear, and it swells or enlarges. Increase the heat still fur- 
 ther, the molecular action increases, the orbit of circula- 
 tion enlarges, and the solid becomes fluid and the fluid aeri- 
 form. Hence heat acts repulsively by the very law which 
 fixes the orbits of rolling spheres, that of increasing cir- 
 cles with increasing force. "We have already referred to 
 the fact, that the volume of the dilating body increases 
 three times in small bodies for its length of increase, indi- 
 cating the ever circular orbit of force. Latent heat is 
 therefore normal molecular action, capacity for heat, that 
 which a body can bear, and use internally without change 
 of condition ; sensible heat shows itself by dilatation and 
 expansion, by the increase of the circular motion of its 
 atoms, and by its transfer. 
 
 Daniell says that the polarity of heat is as certainly 
 demonstrated as the polarity of light, though the experi- 
 ments which demonstrate it are of a more delicate nature. 
 Polarity is circular motion, or rather the indication of circu- 
 
MECHANICAL PHILOSOPHY. 27 
 
 lar motion. It is the direction of the orbit, and, applied to 
 matter through which force circulates, the poles are the 
 anode and the cathode, 'the direction of the current which 
 passes ; or as Whewell describes it : " Polarization indicates 
 opposite properties in opposite directions, so exactly equal 
 as to be capable of accurately neutralizing each other ; that 
 is, the same force passes and repasses circularly with an 
 even power." 
 
 Heat is always accompanied with a greater or less degree 
 of light. This is certain with reference to free current heat. 
 Latent heat and conducted heat are not the subject of exam- 
 ination ; but yet as the breaking up of cohesion manifests 
 light with the evolved heat, it appears almost certain that 
 light is the essential condition of force manifesting itself as 
 heat. What is light ? Not inert sluggish matter, not the 
 disembodied force instantaneously diffusing itself, but the 
 combination of the two. This is the reason of the endless 
 disputes about the materiality and immateriality of light ; 
 both views are partially right, both are wrong. There 
 are indications that will support either side of the ques- 
 tion, but the phenomena collected together result in the 
 union of the two. It is force which gives it its transit, its 
 dynamical laws ; it is matter which strikes the eye and 
 forms the picture there. It is what force transports by 
 which the world is painted in all its glory. It is not " a 
 propagated quality of motion, extending in right lines in all 
 directions from the point from which it emanates ; " but 
 something is borne along on the wings of force so subtile 
 as to be felt only by the most delicate tissue of the animal 
 system, the retina. 
 
 The materiality of light has the support of Newton and 
 the great philosophers of his clay, and of many subsequently. 
 
28 OUTLINES OF A SYSTEM OF 
 
 Its materiality seems demonstrable from its being absorbed 
 bj the vegetable tissues, giving them color and strength of 
 fibre which no " propagated quality of motion " can give. 
 It is inherent in the diamond ; it can be collected from the 
 sun's rays by solar phosphori, and when emanated, the 
 supply can be again received by a fresh exposure to the 
 sun ; it is evolved from decaying bodies and from the liv- 
 ing animal organization ; it obeys the laws of motion, of 
 known moving matter, its line of motion is bent, and when 
 not absorbed by the body on which it impinges, as the pon- 
 derous missile on the ice or water, the angle of reflection is 
 equal to the angle of incidence. 
 
 Light also changes its line of motion in passing through 
 a denser medium. This change of direction is only at its 
 ingress and egress. It is a surface change, determined not 
 by the medium, but by its transit within and without. May 
 not this be the theory of the change ? The atoms of light, 
 being matter, have extension of surface ; they strike the 
 concave or convex lens on their edges as they enter, at an 
 angle, not with their surfaces parallel to the glass ; on the 
 egress one edge escapes while the opposite is yet resisted 
 by the denser medium ; to use a popularly technical word, 
 they are canted by the convex towards a centre, by the con- 
 cave from a centre or focus, both on entering and leaving 
 the glass. It appears, too, as if light were composed of 
 atoms of different extensions, as by the prism these atoms 
 are separated by their greater or less impinging surfaces. 
 The fall of a flat piece of wood angularly on the water which 
 would be turned, illustrates the idea ; in the case of the 
 atom of light, the concave or convex glass would make the 
 angle. Does not this also explain the angle of reflection ? 
 It is remarkable, too, that the refractive powers of media are 
 
MECHANICAL PHILOSOPHY. 29 
 
 in proportion to their densities ; water acts more powerfully 
 than air, and the power of water is increased by its having 
 salt in solution. Bring to the mind, too, that the change of 
 direction is at the surface only, and we must impute it to 
 the manner of its entrance by surface change. A wave of 
 ether or a " propagated quality " of motion by act of im- 
 pingement would accommodate itself to the angle of im- 
 pingement, as do the waters of the ocean to the projecting 
 cliffs of the shore. The theory illustrates the phenomena, 
 even if it be drawn from the imagination only. 
 
 But it will be thought that our view is too mechanical 
 and rough to be affirmed of light ; for how exceedingly 
 minute must be those particles which in myriads cross and 
 recross without impingement ! Space is indeed incompre- 
 hensible in its minute divisions, as in its most extended 
 bounds. It seems to flow out on either side, in wave- 
 like undulations, upon the confines of infinity, with 
 which it blends without distinctness of separation. Obscure 
 as it is to us there is about the atom room, fixed laws, accu- 
 racy of motion, and to higher beings the laws of God, 
 operating in a mere point, may be as palpably distinct, 
 as to us is the waving of the branches of the tree that 
 bends before us in the summer's wind ; and because the 
 motion of the atom is obscure to us, must we throw upon it 
 the reflected light from the phenomena which nature, in her 
 enlarged sphere, places before the eye. We understand 
 the minute only as we comprehend the extended ; for they 
 both have the one God over them, whose law is universal, 
 unchangeable in reference to the atom and to the sphere. 
 
 We advert but to one more of the phenomena of light, 
 its polarity or the circular motion of its atoms. This is the 
 stamp of force, its great characteristic, ever denoting its 
 3* 
 
30 OUTLINES OF A SYSTEM OF 
 
 presence. We will describe polarization in the words of 
 Daniell. " It may assist our comprehension of the pheno- 
 mena to illustrate them by a rough analogy ; a ray of com- 
 mon light as it is emitted from a self-luminous body, we may 
 conceive to revolve upon an axis coincident with its own 
 direction, as a cylindrical rod may be made to turn, or 
 which comes to the same thing, the reflecting or refracting 
 surface may be made actually to revolve around the ray as 
 an axis preserving the same relation to it, and no change in 
 the phenomena will be perceived." We add, that the 
 rolling earth flying in her orbit would be an illustration 
 perhaps more apposite. 
 
 We proceed to the examination of electricity. Franklin, 
 with the sound discrimination which characterized his mind, 
 expressed the truth in relation to it. We will quote his 
 language, substituting the word " force " for " electrical 
 fluid." " The opposite states of electrical excitement depend 
 upon the increase or diminution of force relatively to the 
 two bodies." These two states have been called the positive 
 and negative. When two substances are rubbed together, 
 sometimes the one and sometimes the other is excited. All 
 substances have been divided into electrics and dialectrics, 
 the one the conductors, the other the non-conductors of elec- 
 tricity ; but subsequently it has been ascertained that all 
 substances are conductors, their conducting powers differing 
 only in degree. Hence we have not conductors and non- 
 conductors, but substances differing in being good or bad 
 conductors ; the metals, water, animal and vegetable bodies 
 on the one hand, and oil, glass, dry air on the other. There 
 is in the extremes a striking difference of atomic structure, 
 as for instance, in iron and spermaceti. 
 
 Any dissimilar substances rubbed together with proper 
 
MECHANICAL PHILOSOPHY. 31 
 
 precautions are capable of exerting the power, one of them 
 becoming excited. The effect is produced by the applica- 
 tion of force, nor does it change its nature. When confined, 
 it is force ; when again set free, it is force. Electricity is 
 thus described : " It is freely evolved by the mechanical 
 action of heterogeneous substances ; still more abundantly 
 by chemical action ; it is a product of animal organization ; 
 it is capable of evolving heat, and heat is capable of evolv- 
 ing electricity. It is capable of acting on bodies in oppo- 
 sition to gravity, and is capable of the most energetic action 
 on its own constituent atoms. Every form of matter may 
 be excited to its action, and it may be transferred from one 
 portion of matter in which it has been called forth, to 
 another previously in its natural state." We could not 
 more distinctly describe force. Electricity is force existing 
 under some peculiar conditions. Its polarity is one of its 
 most prominent phenomena. It can be insulated, or a 
 channel formed for its circulation ; it can be kept a pris- 
 oner, or its path opened that it may return to the earth, 
 and add the strength of its feeble stream to swell the torrent 
 of force which ' bears along the mighty orb in her rolling 
 path. 
 
 Differing from galvanism, which appears as a continuous 
 stream of force, electricity is, as it were, a collected mass, 
 a sphere revolving on the surface of the glass. It does not 
 seem to affect the molecular action, but to pass through the 
 aggregated atoms as free, revolving in its own orbit ; for, 
 if you break the cylinder which contains it, the electrical 
 spark is found in one of the parts only. Electricity, too, 
 gives another striking demonstration of its nature. We 
 quote : " If the electricity collected be distributed between 
 balls of different diameters, it will be found that, the smaller 
 
32 OUTLINES OF A SYSTEM OF 
 
 the sphere, the more intense the action." Such is the law 
 of force, wherever it exists ; there is circular motion, equal- 
 ity of diffusion, the velocity increasing with the decrease of 
 the diameter of the orbit. In the excited rod, too, the action 
 is more intense at the ends than at the centre ; for the law is 
 that of increased speed with the narrowing diameter of the 
 elliptical orbit. Electricity gives to matter no attractive 
 power, as it partially escapes from its receptacle, it draws 
 or repels other bodies towards or from its receptacle ; and 
 whether attracted or repelled, the moving body determines 
 its motion by its own state of excitement. If equally ex- 
 cited, it adds to the circulating force ; if less excited, it 
 absorbs a part of the circulating force. No attraction of 
 matter can be affirmed of this fitful, spasmodic action of 
 bodies floating in the vortices of revolving force. How 
 beautiful the provision by which the unexcited body advances 
 to the excited, then in contact receives its burthen to be 
 conveyed to other bodies, so that the resultant motion of 
 vertical force is the equal distribution of that force, an 
 equilibrium preserved not by opposing forces, but by the 
 very nature and laws which govern the action of force. 
 
 Galvanism is the result of the breaking up of existing 
 structures, thereby freeing the force which bound their 
 atoms together. Would any one ask what is the cement of 
 the building when, by its destruction, the earth is covered 
 and the air filled with lime? It is the force of cohesion made 
 current, which constitutes galvanism. The condition of its 
 being " current affinity" is decomposition, and a conduct- 
 ing circuit or orbit in which it is to move. " Now," says 
 Daniell, " it is curious to observe how chemical affinity in 
 all these experiments waits upon the conducting and col- 
 lecting power ; the strong attraction of zinc for oxsulphion 
 
MECHANICAL PHILOSOPHY. 33 
 
 is held in complete check till a passage is open for the circu- 
 lation of the force ; the force which circulates must be equal 
 in all parts of its circuit, it stops with the slightest break in 
 the continuity of its conductor." Urged sometimes by 
 the intensity of the charge, it leaps through a short space 
 of air, and then with its flame arched upward, proclaims 
 the tendency of force to assume the circle, whose circum- 
 ference is proportional to the degree of the force which 
 revolves. 
 
 Dr. Farraday has proved that the contact of dissimilar 
 metals is not necessary to the generation of the current, and 
 that the force is always in exact proportion to the amount 
 of chemical affinity. With a knowledge of the laws of force, 
 this fact needed not the demonstration of experiment ; for 
 the force of cohesion liberated must measure the current 
 force ready to act in new combination, or to pass for exam- 
 ination along the conducting wire to the matter it is to bring 
 together in newly built structures. How beautiful, too, the 
 analogy between the chemist and the mechanic ; the former, 
 commanding for his work the force once used for cohesion, 
 and again directing its strength for a similar purpose ; 
 the latter, using as his property the force of a moving 
 world, directing it in the circuit of his machinery, that it 
 may destroy structure and build other structures that min- 
 ister to human wants. This very analogy has been thus 
 traced out. " The analogy of the transmission and direction 
 of mechanical force, may perhaps assist in the formation of 
 a clear idea of this influence of bodies," [current affinity.] 
 " Every one is familiar with the modes by which the mus- 
 cular force of animals, the elastic force of steam, &c., is led 
 by the solid matter of levers, cords, and wheels to distant 
 points from its source arid there set to work, somewhat in 
 
34 OUTLINES OF A SYSTEM OF 
 
 the same way we may conceive that the force of affinity may 
 be directed to distant points through appropriate conductors. 
 But its journey ings must be in a circle, and the arrange- 
 ment must be made in such a way that the impulse may 
 return to the point from which it set out ; it must circulate." 
 
 " In no case," says Farraday, " is there a pure creation 
 of force, a production of power without the exhaustion of 
 something to supply it." Of course it has excited the won- 
 der of chemists, that two pieces of metal, producing no 
 change in their states, should be an inexhaustible source of 
 power. The wonder ceases when the distinction is made 
 between current affinity brought into action, and continuing 
 in action in its orbit, and the current affinity from broken 
 cohesion, returning after its circuit to rebuild from the ele- 
 ments which had been torn asunder, at the broken orbit 
 between the positive and negative pole. The one is seen in 
 the action of the magnet, the other in the passage of the 
 galvanic current, passing from the work of destruction 
 through the wire to the work of re-creation, or at once 
 passing through bodies in chemical affinity. 
 
 Before we proceed to the examination of the union of the 
 magnetical and electrical phenomena and the action of the 
 magnet, we will explain our views more fully of the effect of 
 the galvanic current in changing the condition of bodies on 
 which it acts. Polarity is the positive and negative pole, 
 or the direction of the current force. The wire is the con- 
 ducting circuit, between the poles of which is the substance 
 acted upon. " Now the idea of polarity," says Whewell, 
 " involves the conception of opposite properties in contrary 
 directions ; for example, attraction and repulsion, darkness 
 and light, synthesis and analysis." That is, force revolves, 
 the current in its passage one way repels, in the other 
 
MECHANICAL PHILOSOPHY. 35 
 
 attracts ; in one way gives darkness, in another way light ; 
 it breaks down structure or rebuilds structure, for in one 
 way force is taken from the body and from the other pole it 
 returns. In the one case, for instance, it resolves water 
 into its constituent gases, in the other combines the ele- 
 ments of water into that fluid. This proves that our idea 
 of polarity is right, and opens the mystery of chemical 
 action generally ; for the same result is had without the 
 wire, the transfer of force. Farraday expresses the idea 
 in almost the same language. " Chemical synthesis and 
 analysis must be conceived as taking place by virtue of 
 equal and opposite forces, by which the particles are sepa- 
 rated or united," that is, by the transmission of force. 
 
 We continue to quote : " These forces, by the very con- 
 sideration of their being polar, may be transferred from 
 point to point, and thus we have a positive force active at 
 one extremity of a line of particles corresponding to a nega- 
 tive force at the other extremity ; all the intermediate par- 
 ticles neutralize each other's action.'' This idea was 
 introduced by Prout, confirmed by Davy, and fully illus- 
 trated by Farraday ; and for its full comprehension it needs 
 only that we discharge the unmeaning expression, ' negative 
 force,' and consider the phenomena as indicating the transfer 
 of force in its circulating orbit. 
 
 In our view of magnetism, we have the labor lessened by 
 the acknowledged fact, that current affinity, or galvanism, 
 or electricity, is identical with magnetism. It is so decided 
 by competent authority. This was first announced by 
 (Ersted in 1820, and proved by a series of experiments. 
 Franklin long before this had induced magnetical polarity 
 in fine needles by passing through them a current of elec- 
 tricity. The disturbance of the polarity of the ship's com- 
 pass is also a well known fact. 
 
36 OUTLINES OF A SYSTEM OF 
 
 We call attention to this phenomenon : place the needle 
 over the conducting wire ; it lies across the path of the 
 rushing force ; beneath, it lies again across the marked pole 
 in the contrary direction. Dr. Farraday succeeded in pro- 
 ducing a revolution of the needle about the wire, and of the 
 wire around the needle. The principal effects of terrestrial 
 magnetism " may be imitated by distributing a wire around 
 the surface of an artificial globe, in a spiral direction from 
 the equator to the poles, the two extremities being turned 
 inwards, brought out at the two axes, by which the connec- 
 tion may be made with the battery. A magnetic needle 
 properly suspended in different situations near the globe, 
 will arrange itself in positions perfectly analogous to those 
 assumed by the dipping needle in the corresponding regions 
 of the earth." The action of conducting wires rolled in the 
 form of the flat spiral, produces on one side the action of 
 the marked (north) pole, and on the other of the unmarked 
 pole of the magnet. 
 
 As it has been remarked, this is the fundamental fact, 
 (the rotary movement accompanying the orbitual,) to which 
 other facts of eZe<?r0-magnetism are reducible. Magnetic 
 bodies derive their power of attraction from the circular 
 movement of force. Within them, extending beyond them 
 to bodies of similar nature within certain distances, the po- 
 larity of magnetical bodies is owing to the secondary or 
 rotative current which invariably accompanies what may be 
 termed the primary motion of force. 
 
 Thu-s is the polarity of the needle upon the surface of the 
 globe indicative of a current of force circulating around the 
 globe in planes parallel to the magnetic equator, increasing 
 in power from the equator to the poles, obeying the general 
 law, increase of intensity with decrease of the orbit. M. 
 
MECHANICAL PHILOSOPHY. 37 
 
 Ampere was the first who recognized the existence of this 
 current, which has been imputed to the influence of the sun 
 upon the tropical regions. That the current flows there is 
 no doubt ; the finger guide, the magnet, is authority ; and it 
 not only indicates the fact, to which we shall often refer, 
 but, what is more important, points to a principle of universal 
 application, the onward primary movement of force is 
 always accompanied by the secondary. Thus orbitual and 
 rotary movement as the law of force is affirmed not only by 
 the movements of the spheres, but by every rivulet of force 
 which has strayed from the mighty channel of power, to 
 be predicated, not only of the career of worlds, but of the 
 action of the most minute particles of matter. 
 
 The preceding remarks also indicate the action of force 
 upon the magnet. By the touch of the loadstone there is 
 given to the atoms of the needle the structure, which deter- 
 mines the flow of force through it in a fixed orbit. Force 
 in any other direction gives motion to the needle on its 
 pivot ; force in the direction of this orbit flows through it, 
 and it is unmoved by it. Thus it oscillates, a motion never 
 produced by a stationary fixed force, but by the absorption 
 and transfer of force. In one direction force gives motion 
 to the needle ; in another direction the force flows through 
 it, presenting a perfect analogy to the oscillations of the 
 pendulum. This idea will be explained as we proceed. 
 
 The attractive power of the magnet may be understood 
 from the process of inducing magnetism. Dispose of two 
 bars of steel in a parallelogram, connect them at the ends 
 with two pieces of soft iron, thus making a circuit or orbit 
 for force, and apply the loadstone; or in a horseshoe magnet 
 connect the extremities by a piece of soft iron, making the 
 circuit, and then apply the force through the medium of the 
 4 
 
38 OUTLINES OE A SYSTEM OF 
 
 loadstone. Thus you have polarity, a direction of the cir- 
 culatory force. The keeper, as the piece of soft iron is 
 called, when attached, is a part of the orbit, and, while it is 
 attached, the circuit of force being complete, the magnet has 
 almost no attractive power. Remove it, and iron, a sub- 
 stance resembling steel in its structure, will be brought by 
 force to finish out the broken orbit. If the loadstone be 
 applied to a circular piece of steel, magnetism is as truly 
 induced, but force revolves latent and unobserved. Such is 
 the delicacy of the established orbit, that a fall upon the 
 floor will often materially affect the power of the magnet ; 
 and magnets, to have their power preserved, should be laid 
 away with the keeper, that is, with the completed orbit. 
 Some additional facts will throw more light on this subject. 
 The concussion of the steel by a hammer, causing it to vi- 
 brate strongly, will aid the process of inducing magnetism. 
 Thus force is supplied, or the molecular movement enables 
 the atoms to arrange themselves in the line for the orbit. 
 After the orbit is established, a sudden jar may disarrange 
 it, by excess of atomic motion ; and oxygen, uniformly the 
 destroyer of structure, always annihilates the orbit. 
 
 An unlettered man, on looking at the action of a magnet, 
 exclaimed, Why, it appears as if it let out a loop of cord to 
 draw something into its place. Well did he indicate the action 
 of force in completing its orbit, and changing it from the 
 elliptical to the circular. Many attempts have been made 
 to convert the magnetical force into motive power for eco- 
 nomical purposes. In vain ; and the reason given for the 
 failure is, the short distance at which magnetic force can 
 be made to act. But a more general principle is the cause 
 of the disappointment, one which, when understood, will 
 prevent any further attempt. The action is such as itself 
 
MECHANICAL PHILOSOPHY. 39 
 
 to complete the circuit, and the revolving interior force is 
 locked up, giving cohesion to the mass. The completed 
 orbit of the magnetic force is beautifully illustrated by 
 pieces of fine wire, cut in lengths of about 1-8 inch, which 
 may be suspended from the magnet, forming a chain or 
 connected loop from one pole to the other. The soft iron 
 receives polarity by this contact without the power of retain- 
 ing it, except when the circulation is maintained by the 
 permanent magnetic structure of the steel. We notice, too, 
 the accumulation of intensity at the ends of the magnetic 
 bar, the ellipticity of the orbit developing as ever the 
 increased velocity of force, just as the comet is drawn with 
 accelerated speed in the sharpest part of its elliptic course. 
 
 We notice in this place, as an idea growing out of the 
 preceding, the difference of structure between the electric 
 and the dielectric, the good and the bad conductors of force. 
 In a strong metallic conductor the force condenses itself, 
 increasing in intensity with the decrease of its orbit, in 
 other words, in the electric it establishes its orbit ; while in 
 the dielectric the orbits for circulation do not exist, or feebly 
 exist. Says Daniell, " In the dielectric the force cannot 
 travel from one end to the other to accumulate at the ends, 
 like the electric forces in the insulated conductor." We 
 refer to this fact now, as it throws light upon the action of 
 imponderables, for instance, force destroying wood, while it 
 enlarges iron ; but mainly because this distinction will add 
 much clearness to our conception of the important conditions 
 of mechanical action in the pressure and friction of bodies 
 in contact. 
 
 Whence is animal force ? We are prepared in some de- 
 gree at least to detect its source, if it lie not too deep in 
 the mysteries of the living organization. The proximate 
 
40 OUTLINES OF A SYSTEM OF 
 
 cause of animal heat (force) is unquestionably respira- 
 tion ; but physiology has not yet arrived at a distinct enuncia- 
 tion of the principle, by which the change in the condition 
 of the inhaled and exhaled air deposits force. It is pre- 
 sumed that it is the breaking up of animal tissues, which 
 are exhaled as the base of carbonic acid. This slow com- 
 bustion, it is said, evolves heat. 
 
 The accelerated action of the lungs by the need of force for 
 unwonted exertion, and the continuous full play of the lungs 
 as denoting permanent strength, tell us as plainly as facts 
 can speak that force comes proportionally to the act of res- 
 piration. If our general view be correct, we shall find that 
 the air has parted with force on its contact with the lungs. 
 It is even so. The air expired is heavier than when in- 
 haled. It has been deprived of force. The formation of 
 carbonic acid is not only the principle of heat, but the con- 
 dition of the force of life in all organic structure. The 
 reason of its transfer of force to the blood, and through it to 
 all the separate parts of the system, is only to be known by 
 understanding the nature of life, which is perhaps wrapped in 
 obscurity by the very belief that its mysteries are inscruta- 
 ble. But should we ever admit that any thing which bears 
 the stamp of the finite is unintelligible ? 
 
 Animal force develops itself under the conditions of heat, 
 light, electricity, galvanism, and, it is said, of magnetism. 
 It is circular in its flow through the system ; the heart and 
 brain establish its polarity or direction. Electricity and 
 galvanism will move the muscles, taking the place of the 
 muscular force. 
 
 Do we wish for more proof of the identity of heat, cur- 
 rent affinity, galvanism, muscular force, of all and every 
 form of power ? If you elevate a body to make it rotate at 
 
MECHANICAL PHILOSOPHY. 41 
 
 a higher level from the earth, thereby increasing the cir- 
 cumference of the circle it must describe, will not either 
 and all of them give to the body elevated its required force ? 
 Are not each and all of them resolvable into the force which 
 moves the spheres ? 
 
 We have passed over this examination of the streams of 
 force with a hurried glance. If these excite our wonder 
 and admiration, what is the feeling with which we fix our 
 attention on the fountain itself, from which these come as 
 the accidental spray and tossing of the ocean ever spread 
 out before us, the force which moves the system of 
 systems, the creation of an eternal and almighty God, re- 
 volving in circle upon circle through limitless space. We 
 stand speechless at the thought of this boundless power up- 
 holding the heavens and the earths ; yet boundless as it is, 
 the strength of creation softly and kindly ministering to the 
 breath of the sleeping child ! 
 
 Whewell expresses the idea of the identity of force in 
 the one hundred and third aphorism of the Philosophy of 
 the Inductive Sciences, in these words : " Mechanical, 
 chemical, and vital forces form an ascending progression, 
 each including the preceding. Chemical affinity includes 
 in its nature mechanical force, and may be often practically 
 resolved into mechanical force," &c. Chemists generally 
 indicate the identity of force by their communication of the 
 fact, that the same matter in its atomic divisions has the 
 same affinity for gravitation, for heat, and for electricity. 
 Thus is pointed out, analytically as well as synthetically, the 
 identity of force. We need not enlarge, as every chemical 
 manual gives the results, and it would be the mere task of 
 the copyist, transferring the sentences of the common books 
 on the science of chemistry. 
 
42 OUTLINES OF A SYSTEM OF 
 
 " We find," says Humboldt, " among the most savage 
 nations, as my own travels enable me to attest, a certain 
 vague, terror-stricken sense of the all-powerful unity of 
 natural forces, and of the existence of an invisible essence 
 manifested in these forces, whether in unfolding the 
 flower and maturing the fruit, in upheaving the soil of the 
 forest, or in rending the clouds with the force of the storm. 
 We may here trace the revelation of a bond of union, link- 
 ing together the visible world and that higher spiritual world 
 which escapes the grasp of the senses. The two become 
 unconsciously blended together, developing as a simple pro- 
 duct of ideal conception the first germ of a philosophy of 
 nature." 
 
 The great error of science is its too minute classification 
 of facts, and the attempt to find for each class of fact a dis- 
 tinct and definite law. Facts are never isolated ; there are, 
 in philosophy, no lines of demarcation between them. It is 
 the poverty of man's intellect that thus subdivides. .Take, 
 for instance, the classes, departments, orders, kingdoms of 
 organic structure. How they fade away one into the other ! 
 How clear on this point is Agassiz, in his Philosophy of 
 Natural History ! Other strong minds follow his investiga- 
 tions. He does not look upon organic structure only as a 
 succession of classes ; he does not affirm laws of local or of 
 special application alone. He views life as a whole, and 
 sees the general law which gives a oneness to creation. 
 He combines when others analyze ; he looks for simplicity 
 where others see diversity. How true is the law of the mind 
 to the law of nature ! The pure conception of the savage 
 seizes the idea of the unity of nature, and the truly great 
 philosopher offers the same as the deduction of the reason- 
 ing power. It is in an intermediate order of minds that we 
 
v^ 
 
 MECHANICAL PHILOSOPHY. 43 
 
 find the errors, the accumulation of unassorted facts, the 
 confusion of conflicting theories. The first thought, natural 
 to the mind, is unity, the last and highest conceptions 
 return to the thought of the pure and simple reason. 
 
CHAPTER III. 
 
 "PHYSICS DISCOVERS CAUSES FROM THEIR EFFECTS AND EFFECTS 
 
 FROM THEIR CAUSES." St. Victor, 
 
 CUKSOBILY must we pass through our examination of 
 capillary attraction, heterogeneous and homogeneous at- 
 traction and repulsion, and chemical affinity ; cursorily, be- 
 cause we need not devote attention to the minor phenomena, 
 as the consideration of the more prominent involves that 
 of the lesser ; for general laws grasp the points, however 
 minute, as well as embrace the aggregate of points which 
 constitute the universe, force under general laws determin- 
 ing the place and position of all things, the minute as well 
 as the extended. 
 
 It is sympathetic motion which forms the continuity of 
 worlds ; and if a mass be formed, it is also by sympathy of the 
 motion of its parts, it exists as a mass by this sympathy of 
 motion, if it be rent asunder, it is by jarring and conflicting 
 motion. If there were not harmony of motion among the 
 spheres, the solar system could not exist. If there were not 
 sympathy of motion among atoms, masses could not exist. 
 From this latter idea are deducible homogeneous and hetero- 
 geneous attraction, the phenomena of filtration, of exosmose 
 and endosrnose, and generally the attraction and repulsion 
 of bodies at distances not too remote for their reciprocal 
 action on each other through the connecting media of air, 
 water, or other substances. 
 
45 
 
 Capillary attraction is certainly inexplicable on the ground 
 of the attraction of matter. As generally understood, mat-' 
 ter attracts in proportion to its bulk. But water, attracted 
 by the thin glass tube, escapes from the attraction of the 
 earth which retains its hold upon the glass tube, yet lets 
 the flowing water elude its grasp, and run up in perfect in- 
 dependence. But the centre of the glass tube has no more 
 attracting power than the ends ; and, if the glass be filled 
 with water, the tube ought to attract downward as well as 
 upward. Indeed there is in this phenomenon not one soli- 
 tary fact to show that the glass attracts the water, except 
 that the water in the tube is concave, rising where in contact 
 with the glass ; nor does this manifest the attraction of the 
 glass, but an attraction upward. Surely if the sides of the 
 glass attracted, the area under the surface would attract 
 downward as well as the area above attract upward. Per- 
 haps wetting the bore of the glass takes away the power 
 of attraction ! 
 
 It has been remarked that " the boldest imagination can 
 hardly form a conception of the undulations rendered latent 
 without annihilation, laid up in store as it were, and capable 
 of being drawn forth in full measure and intensity." This 
 appears to be the idea which leads to the understanding of 
 the phenomena of capillary attraction. These undulations, 
 latent in the water, are brought into the consentaneous mo- 
 tion of the mass inclosed in the narrow tube. It appears as 
 if the range of molecular action were reduced by the con- 
 finement, and the no longer used atomic force is resolved 
 into rotative force at a higher level. In mercury, the action 
 is perhaps the converse ; the atomic force of the glass may 
 be increased, and force be withdrawn from the fluid metal. 
 We thus offer a more consistent theory than the old theory, 
 
46 OUTLINES OF A SYSTEM OF 
 
 even if it be not true, and its truth may be rendered more 
 apparent by our proposed examination of the properties of 
 fluids. 
 
 We read, however, that " it has been proved by experi- 
 ment that mercury will rise above its level in the same man- 
 ner as water, when both the tube and mercury are per- 
 fectly dry. The mercury being dried by repeated boiling, 
 is freed from its humidity. It appears, therefore, that the 
 depression of the mercury below the level is occasioned by 
 a little moist film, which attaches itself to the interior sur- 
 face of the glass, and thus by its interposition, perceptibly 
 weakens the attractive force of the glass," &c. The effect 
 on the phenomena of capillary attraction will be further 
 elucidated in the prosecution of this inquiry. One thing is 
 certain, the rise of water is not from the attraction of the 
 glass ; for the glass would attract downward as well as 
 upward, especially as aided by the attraction of the earth. 
 It has been supposed that the ring of glass above the sur- 
 face is the attractive cause. By others, as by Dr. Hamilton, 
 " that the fluid is supported by the attraction of the annulus 
 contiguous to the bottom of the tube." The bulk of sup- 
 ported fluid is not proportional to the surface of the glass 
 with which the fluid is in contact. Of course, " gravitation " 
 in capillary attraction is out of the question. 
 
 Elasticity is the property of bodies, the particles of which 
 have a wider space and larger vibrations, which vibrations 
 can be lessened for the time by the application of outward 
 force. Glass, for instance, is extremely elastic, and the 
 wide separation of its atoms gives it, probably, its transpa- 
 rency, and perhaps its peculiar properties in relation to 
 electricity. Air is highly elastic, and is distinguished by the 
 readiness with which it receives and transports the vibra- 
 
MECHANICAL PHILOSOPHY. 47 
 
 tion of denser media of force. It acts as the conveyer 
 of motion, as the distributor of power, trembling before the 
 least impulse, yet spreading out the vibration in every 
 direction, till the moving force is equally distributed and 
 the equilibrium is again restored. 
 
 Cohesion is supposed to be a branch of the attractive 
 force of matter. This force, it is said, " connects the par- 
 ticles of bodies together in the solid form with greater or 
 less energy." To increase or diminish this force so as to 
 keep the particles from actual contact in adamantine hard- 
 ness, and to give the different energies of cohesive power, 
 an antagonist power is imagined, the repulsive force of mat- 
 ter, " separating the particles of bodies from each other with 
 greater or less energy." Like Mahomet's coffin, the atom 
 hangs midway in the rest of perfect equilibrium. But, 
 alas ! bodies in equilibria move at the softest touch, and the 
 particles of the solid iron would tremblingly oscillate as the 
 slightest breath of wind passed over them. 
 
 A better knowledge of the action of current affinity, 
 that is, the acknowledgment of the laws of force developed 
 by the recent experiments of distinguished chemists, has 
 led to the supposition that cohesion is induced by the revo- 
 lution of electrical force through the mass, though the belief 
 is not yet generally or distinctly avowed. " Schelling, in 
 1803, says," we quote from Whewell, " magnetism is the 
 universal act of investing multiplicity with unity." Accord- 
 ingly we find Schelling welcoming, with a due sense of their 
 importance, the discoveries of Farraday : " When he heard 
 of the experiment in which electricity was produced from 
 common magnetism," he thus reasoned; "we have three 
 effects of polar forces, electro-chemical decomposition, 
 electrical action, magnetism. Volta and Davy had con- 
 
48 OUTLINES OF A SYSTEM OF 
 
 firmed experimentally the identity of the two former agen- 
 cies ; (Ersted showed that a closed Voltaic circuit acquired 
 magnetic properties ; but in order to exhibit the identity of 
 electric and magnetic action, it was requisite that electric 
 force should be extricated from magnetic. This great step, 
 he remarked, Farraday had made in producing the electric 
 spark by means of the magnet." Whewell continues, 
 " Although conjectures and assertions of the kind thus put 
 forth involve a persuasion of the pervading influence and 
 connection of polarities, which persuasion has already been 
 confirmed in many instances, they involve this principle in 
 a manner so vague and ambiguous, that it can rarely in 
 such a form be of any use or value." From the opinion of 
 one so distinguished by reasoning power, it is perhaps pre- 
 sumption to differ ; but it is deemed that polarity, or in other 
 words, circulating bands of force are the only possible tie 
 for continuity of mass, for the connecting bonds of the solar 
 system, for, in the words of Schelling, " the act of in- 
 vesting multiplicity with unity." We will give our reasons 
 for this opinion as they have occurred to us. 
 
 There has been established a connection between magnetic, 
 electrical, and optical, and between these and crystalline po- 
 larity ; and crystallization is the taking up of the bond of the 
 cohesion of solids. Bodies never crystallize, except when 
 their elements combine chemically, and solid bodies which 
 combine, when they do it most completely and exactly, also 
 crystallize. The forces which hold together the elements of 
 a crystal of alum are the same forces which make it a 
 crystal. There is no distinguishing between the two sets 
 of forces. Accordingly, Berzelius asserts that the regular 
 forms of bodies suppose a polarity, which can be no other 
 than the electrical or magnetic polarity. Again ; " the 
 
MECHANICAL PHILOSOPHY. 49 
 
 identity of a crystalline and optical polarity is too obvious 
 to need insisting on." Thus much from authority of these 
 latter days ; and we quote the words of Newton : " Would 
 it were permitted us to deduce the other phenomena of na- 
 ture from mechanical principles, and by the same kind of 
 reasoning ; for many things lead me to suspect that all these 
 phenomena depend on certain forces by which the particles 
 of bodies are either urged toward each other, through 
 causes not yet known, and cohere according to regular fig- 
 ures, or are repelled and recede from each other ; which 
 forces being unknown, philosophers have hitherto made 
 their attempts upon nature in vain." 
 
 We are disposed to believe that the ultimate particles of 
 bodies have an orbital or rotary motion, intense in propor- 
 tion to the circumscribed space in which they move. In 
 every mass, also, and at times extending beyond the mass", 
 (as especially the object of perception in the magnet,) this 
 motion exists, the phenomena of which are those of polariza- 
 tion, and the result of which is cohesion together with the 
 phenomena of friction, and perhaps of chemical affinity. 
 The force revolving in the mass is cohesion, out of the mass 
 friction or pressure, and the change of the structure of the 
 mass is chemical action. These ideas we will attempt to 
 develop. 
 
 The magnet, which by its polarity indicates the passage 
 of the current of force, by its attractive power will indicate 
 the nature of cohesion. The magnetized steel has a circu- 
 lating force, which will leap out of the boundaries of the 
 mass to bring to its embrace another mass of iron or steel. 
 Close the circuit with the keeper, and the force revolves 
 within, as the bond of cohesion between the keeper and the 
 magnet, and not only so, but as the bond of cohesion be- 
 5 
 
50 OUTLINES OF A SYSTEM OF 
 
 tween the atoms of the magnet. Thus every mass has its cir- 
 culating bond of force, beyond which its particles may not 
 stray ; and it would seem as if nature, having no fondness 
 for mystery, hermetically seals up none of her processes, 
 but protrudes the force of cohesion of the steel, that it may 
 be perceived, and that what preserves the continuity of every 
 mass may thus be known. In the horseshoe magnet with its 
 keeper the current of force circulates, latent and unper- 
 ceived but by the pendent keeper which completes the orbit. 
 In the circular steel the force is just as active, without indi- 
 cation except by the general cohesion of the mass. So in 
 the bar of iron. Thus by the simple law of nature there 
 is continuity of mass, oneness from multiplicity ; the bond 
 is the revolving force. Its precise manner of action may be 
 traced out. 
 
 Science as yet has hardly recognized the existence of 
 electricity and magnetism, except in the incidental exhibitions 
 of their power in the magnetic needle, in the flash of the 
 lightning, in the artificial spark rubbed from the glass cylin- 
 der in the lecture-room. But they are everywhere a mighty 
 branch of the great stream of force upholding the universe, 
 connecting together the creation of God. 
 
 To repeat a former illustration, would you ask the nature 
 of the cement of the brick building, which, when it was 
 torn down, filled the air with the dust of lime ? Break up 
 the cohesion of the mass, and heat is evolved ; can you then 
 separate heat in your mind as something opposite to, and dis- 
 tinct from the electrical force ? Rub substances together, 
 electricity starts forth ; does not electricity then circulate 
 to the very surface of the mass, and often beyond the mass ? 
 
 Pressure is therefore the connection of foreign bodies in 
 near contact, by the force of cohesion extending itself from 
 
MECHANICAL PHILOSOPHY. 51 
 
 mass to mass. The phenomena of friction abundantly 
 prove this. First, because, though friction bears a general 
 ratio to the quantity of matter rubbed together, it is not an 
 invariable quantity, as it would be if it depended solely on 
 the weight of the mass. But the subject must be examined 
 in its details. 
 
 Friction, or the degree of friction, if it were induced by 
 weight or gravitation, would be almost, if not altogether, an- 
 nihilated in a smooth body moving horizontally on another 
 smooth body, which is not the case. If the degree of fric- 
 tion were caused by weight, it would be a constant value, 
 measurable by the weight, which is not the case. If the 
 degree of friction depended on smoothness of surface, it 
 would be measured by the polish, which is not the case. If 
 the phenomena of friction arise mainly from the passage of 
 electricity between the rubbing bodies, it will have a gen- 
 eral relation to the extent of the masses ; it will be variable 
 in degree ; it will be increased or diminished according to 
 the electric nature of the substances ; it will be increased by 
 the presence between the rubbing substances of conducting 
 bodies, and decreased by the presence of non-conducting 
 bodies ; it will be increased by the rubbing together those 
 substances inducing magnetical or electrical action, and the 
 converse, all which are settled facts. 
 
 Thus M. Colomb has determined by experiment that 
 friction is increased between bodies of the same weight and 
 the same smoothness, by the act of rubbing together, by the 
 gradual induction of the electrical force. Bodies of differ- 
 ent structure obtain their maximum of pressure in differ- 
 ent times. For one instance, a weight of one thousand six 
 hundred and fifty pounds in contact was moved at first with 
 a force measured by sixty-four pounds ; in the lapse of three 
 
52 OUTLINES OP A SYSTEM OF 
 
 seconds, it required a force of one hundred pounds ; in 
 three days, six hundred and twenty-five pounds would 
 hardly move it. 
 
 Again ; to create the electrical state it is not necessary that 
 the bodies should be rubbed together, it being induced at 
 times by contact merely. The iron wheel of the locomotive 
 only touches the track, bears upon it, and is lifted. If there 
 were no rnagnetical action, the wheel would turn at the 
 axle, but not impel the train. Yet the circumference of the 
 wheel must adhere, for propulsion. If the non-conducting 
 substance, ice or snow, is on the track, then this electrical 
 action is so much reduced that the pressure is not sufficient 
 to turn the wheel ; or rather the wheel turns by the con- 
 ducting rod, but for the want of electrical action, pressure, 
 friction, weight, call it what you will, it takes no hold 
 upon the track, and the locomotive cannot advance. A prac- 
 tical engineer in conversation indicated his knowledge of the 
 fact, that the passage of the train over the track induces 
 magnetical action. Pointing to a pile of unused railroad 
 bars, he said, " Those bars have been exposed to the air a 
 few days only, and they are red with rust, while the bars 
 laid down for years in constant use scarcely show rust. Is it 
 not," asked he, " the effect of magnetism ? " When we ride 
 swiftly over the winter railroad, the snow, one is apt to 
 think of the smoothness of the snow only as decreasing the 
 friction of the runners of the sleigh, forgetting that ice is a 
 non-conductor of that which determines friction. 
 
 Of course, when we speak of friction, we know that it is 
 modified by smoothness of surface, that rough surfaces 
 cannot be rubbed together without force to break up the 
 cohesion of the projecting points ; but, aside from this 
 with equal polish, the extent of pressure is measured by the 
 
MECHANICAL PHILOSOPHY. 53 
 
 passage between the surfaces of the electric or magnetic 
 force. Thus of iron rubbing on iron the pressure may be 
 indicated by the fraction f, while iron rubbing on copper, 
 with no smoother surface, stands at ^ ; for the reason that 
 iron and iron excite the more intense magnetical action. 
 
 The effect of oil as a non-conductor, decreasing pressure 
 and friction, is perfectly indicative of what constitutes pres- 
 sure and friction ; and so is the converse practical act : if 
 we wish to walk securely on ice, we must excite electrical 
 action, put on the woollen moccasins ; " coarse woollen and 
 glass or ice excite the electric action." Thus empirically 
 do mechanics excite or repress friction, often without 
 the least reference to principle. Oil and ice are smooth, 
 slippery, &c. Why slippery, has not been indicated. In 
 the manufacturing of plate glass, two plates placed with 
 their surfaces in contact, are sometimes found to adhere 
 with such strength of cohesion at the former surface of 
 separation, that, in the act of separating them, the split is 
 not coincident with the line of junction. Oil, or any other 
 non-conducting substance, would prevent this formation of 
 cohesion between them. We have the following facts from 
 one practically well acquainted with machinery. A piece of 
 smooth cast iron revolving on other cast iron, without oil, 
 will often file away the iron on which it revolves with great 
 rapidity, the iron dust falling as saw-dust from the sawed 
 wood. A revolving spindle? or other wrought iron body, 
 moving on a wrought iron axis, without oil, will often increase 
 its friction until the motion is stopped by it, and the two 
 pieces of iron will be found cemented or welded together, 
 so as not to come apart at the former surfaces, and when 
 separated the grain of the iron is broken. " I have been 
 told," said he, " of mills being stopped by this adhesion of the 
 
 5* 
 
54 OUTLINES OF A SYSTEM OF 
 
 gudgeon of the propelling wheel for the want of oil." Other 
 instances will occur to every one, such as the close adhe- 
 sion of two pieces of glass when wet, their slight adhesion 
 when greased ; the two drops of water kept from union by 
 a thin coating of dust ; the stratum of oil over water pre- 
 venting the water from freezing, though cooled below the 
 point of congelation ; air prevented from penetrating the 
 wire gauze when wet ; the non-ascent of water in capil- 
 lary tubes composed of a material that cannot be wetted ; 
 the spreading of oil in woollen cloth ; the repulsion, as it were, 
 of oil and water ; the rise of water in the pores of a lump 
 of sugar ; the process of the solution of the sugar. In fine, 
 the whole class of phenomena of what is called homogeneous 
 and heterogeneous attraction, is traceable to this principle, 
 the extending, imparting, diminishing, taking away the 
 bonds of cohesion by the presence of body with body, 
 according to their electric and dielectric natures. 
 
 We read in old philosophy, " that flat and smooth sur- 
 faces of metals, glass, &c. do also adhere with considerable 
 force, but with some other bodies a certain artifice is required 
 for the purpose, namely, the interposition of some fluid, as 
 oil or water, &c., or of some substance that may be applied 
 in a soft state, which will after coagulate and grow solid, as 
 tallow, wax, and fluid metals. Where something is inter- 
 posed, the cementing or adhesion seems not to take place 
 between the two surfaces, but between each of those sur- 
 faces and the interposed substance ; for, in the first place, 
 it seems strange that the surfaces should have a greater 
 attraction when something is interposed than otherwise ; and 
 secondly, it has been found that the adhesion differs accord- 
 ing to the different substance inserted between." 
 
 Hence adhesion is not the attraction of the adhering sub- 
 
MECHANICAL PHILOSOPHY. 55 
 
 stances. The artifice of cements is the interposition of some 
 substance, the electrical nature of which is such as to per- 
 mit the force of cohesion of the two masses to pass and 
 circulate through both ; it is the enlargement of the orbit of 
 the circulating force ; it is making common orbits from 
 special orbits ; it is extending the bond of continuity. The 
 act of soldering is an instance of this process most perfectly 
 accomplished, as the interposed substance is of the same 
 structure and elementary constitution with those united. 
 We notice also the converse in the amalgams which mer- 
 cury forms with other metals ; the mercury becoming to a 
 degree solidified, the other metal to a degree made fluid, 
 so as to produce the mean of the cohesive force of the 
 mingled metals. 
 
 There is also a modification of the force of cohesion by the 
 mechanical addition of force. Let a heavy weight be sus- 
 pended by a copper wire, the wire will remain of the same 
 length ; but by striking the suspended weight so as to give a 
 vibratory motion to the particles of copper composing the 
 wire, the wire will become longer ; there is added force, 
 greater molecular motion, wider orbits, and of course a 
 lengthened wire. Crystals form in a saturated solution by 
 the addition of force in agitating the water. Crystals also 
 are formed on foreign substances, by the extension of the 
 force of cohesion from the bodies on which they form. 
 Light, which is a form of force, induces crystallization. 
 
 "When one substance is rubbed upon another, the body in 
 motion preserves its own force of cohesion, and breaks up 
 the cohesion of the body at rest on which it moves. This 
 fact is illustrated by the tallow candle fired from the gun, 
 the tallow by its velocity or intense present force preserving 
 its own cohesion, and breaking up the cohesion of a far 
 
56 OUTLINES OF A SYSTEM OF 
 
 harder body; also by the action of the comparatively 
 softer grindstone, in its revolution wearing away the harder 
 steel ; and by the diluvial striae, which are grooves worn 
 into the surface of the rock, by the rapid passage of an 
 angle of a rock no harder than itself. 
 
 The destruction of cohesion by the act of cutting with a 
 keen instrument, is much more nearly connected with elec- 
 trical action than is generally supposed. It is well known 
 that the electric spark will, under certain conditions, per- 
 forate a glass jar ; its perforation of the pasteboard card is 
 a frequent experiment. Steel has high magnetic proper- 
 ties ; and the intensity of the action of electrical force is 
 increased in proportion to the reduction of its orbit of circu- 
 lation. We have, then, in the sharp edge, for instance, of 
 the razor, the condition of great electrical activity. It has 
 often been remarked that the keenness of the edge varies 
 without assignable cause. A condemned razor, used acci- 
 dentally, will sometimes be found to have its edge restored 
 by lapse of time. The strapping of the razor is usually on 
 non-conducting substances ; but the edge is often restored 
 by strapping on metallic surfaces. Between both a fine 
 edge can be obtained, as if the keenness depended on one 
 exact degree of magnetical induction. Strapping does not 
 wear away the steel, or make the edge thinner ; for strap- 
 ping on the palm of the hand will often be effectual. The 
 nature of the stroke which severs, strengthens the opinion 
 that the act of cutting with the keen edge is not dependent 
 on force to break cohesion, but on the electrical induction. 
 Thus by establishing correct theories in relation to actions 
 of an enlarged sphere, even trivial operations and the com- 
 mon arts may be improved. 
 
 From all the foregoing we are led to believe that the 
 
MECHANICAL PHILOSOPHY. 57 
 
 circulation of force is the bond of cohesion, and that the 
 acts of separating and of connecting, of lubrication and 
 of cement, of pressure and of friction, are electrical phe- 
 nomena. 
 
 To Boerhaave is assigned the honor of originating the idea 
 that chemical affinity is a peculiar force, having under its 
 control the elementary particles of matter. By affinity in 
 this use of the word is meant attraction. The word affinity 
 was first used in France, to avoid the word attraction, 
 " which had the taint of Newtonism." Elective affinity 
 expresses a choice of matter in the exercise of its attractive 
 power. Berthollet asserted that affinity is not elective, 
 that, when various elements are brought together, their 
 combinations do not depend on the kind of element, but 
 upon the quantity of each which is present, that which 
 is the most abundant entering most largely into the resulting 
 compounds. This doctrine was assailed, and the celebrated 
 chemist Berzelius says, " Berthollet defended himself with 
 great acuteness, which makes the reader hesitate, but the 
 great mass of facts finally decided the point against him." 
 The theory of Dalton. at present the accepted theory, rests 
 upon the idea of substance as well as upon that of choice by 
 the attracting power. 
 
 If we affix the usual meaning to the words choice, prefer- 
 ence, election, the idea is very unphilosophical. If the 
 words be retained in chemical science, they must be under- 
 stood as conveying no other meaning, than that chemical 
 action is determined by the laws of force, which destroy 
 and rebuild the structure of masses. The laws of force 
 never vary ; their seeming changes in relation to the move- 
 ments of particles come from defective observation, and 
 reason must supply the deficiency of perception. We must 
 
58 OUTLINES OF A SYSTEM OF 
 
 interpret the minute by knowledge gained from the ex- 
 tended. Thus, water and oil will not chemically unite. 
 Why ? The action of oil in preventing the union of iron 
 with iron is from its dielectric properties. It is an electrical 
 phenomenon. So water and oil, from their opposite elec- 
 trical natures, from the want of force equally and commonly 
 diffused, will not unite chemically. We cannot form one 
 mass or volume from the two. Add an alkali, and the 
 union of the three substances is formed. What analogical 
 action is there in the extended ? Does not non-conduct- 
 ing matter separate bodies or repress friction ? Is not 
 the action of cements founded on the relations of the vary- 
 ing capacities for force ? We shall again advert to the 
 subject, perhaps better prepared to entertain the position, 
 that the law which determines union is the capacity of the 
 bodies present equally to diffuse the force of cohesion, and 
 the more intimate bond of connection. Chemical union is 
 of the same nature, the one mingling the elements, the other 
 mingling the particles ; the one determining the chemical 
 nature, the other determining the mass of aggregation ; the 
 one effected by the force of cohesion, the other by the force 
 of constitution. Both are of the same nature, and under 
 the action of the same laws. 
 
 It may be objected to this view that the generalization 
 is too far extended. But we can hardly err on this side. 
 The present state of philosophy seems to demand generali- 
 zation, the grouping together of the heretofore isolated 
 action of nature. Nature has been too much parcelled out, 
 too much separated into artificial departments. There 
 have been too many tribunals set up, each with its own 
 code of laws. Such divisions are not characteristic of 
 the simplicity of truth ; but have been made from the 
 
MECHANICAL PHILOSOPHY. 59 
 
 necessity of the case. There is an error in the theory 
 which relates to general principles. Gravitation cannot be 
 brought down to the particulars ; it will not apply to the 
 minute. It has to be added to, or taken from ; it has to be 
 modified for every class of phenomena. Thus have we grav- 
 itation, attraction, elective attraction, capillary attraction, 
 attraction of cohesion, attraction dynamic, attraction statical, 
 attraction between elements of one kind, attraction be- 
 tween masses of different kinds, and so on, almost without 
 end ; and in place of science giving method to the mind, 
 clearness and distinctness to thought, the intellect is embar- 
 rassed in its attempts to assign to nature the modicum of 
 order which the theory itself may have in minds of the 
 greatest strength. 
 
<"'.! **' 
 
 CHAPTER IV. 
 
 " TVE ARE NOT TO ADMIT OTHER CAUSES OF NATURAL THINGS THAN 
 SUCH AS ARE BOTH TRUE, AND SUFFICE FOR THE EXPLANATION 
 OF THEIR PHENOMENA." NewtOH. 
 
 THE third law of motion is usually expressed in these 
 words : " Action and reaction are equal, and in contrary 
 directions ; that is, equal and contrary changes are pro- 
 duced on bodies which mutually act on each other." 
 
 Sir Isaac Newton seemed to consider the equality of 
 action and reaction in the light of an axiom deduced from 
 the relation of ideas, rather than an idea induced from 
 the observed relations of things, to be believed by a 
 law of the mind rather than from observation of phenomena. 
 From this law of the mind, " he presumed, because the sun 
 attracted the planets, those also attracted the sun ; and he 
 is at much pains to point out to astronomers, the phenomena 
 by which this may be proved when the art of observation 
 shall be sufficiently perfected." But Mr. Robison, in his 
 Elements of Mechanical Philosophy, considers this doubt- 
 ful, and says that, because a magnet causes the iron to 
 approach towards it, it does not appear that from a law of 
 the mind we are led to the belief that iron also attracts the 
 magnet. He therefore states it as a fact with respect to 
 all bodies " on which we can make experiment or observa- 
 tion fit for deciding the question." Maclaurin does not 
 consider it as deducible a priori from abstract considera- 
 
MECHANICAL PHILOSOPHY. 61 
 
 tions, but thinks of it as the effect of an arbitrary arrange- 
 ment. Mr. Stewart says that it is " more safe and more 
 logical to consider it as an experimental truth, without ven- 
 turing to decide on either side of the question." The origin 
 of the idea we trace, however, neither to the relations of 
 ideas, nor to the relations of things, but to the action of the 
 human body in the exertion of its muscular power. When 
 we attempt to move a heavy mass, there is a feeling as if it 
 withstood the strength, reacting as it were against the effort 
 put forth. This is probably the origin of the idea, and it 
 serves in almost every treatise on the subject as an illustra- 
 tion of the law. 
 
 The observed facts which give support to the law are all 
 such as manifest the continued action of the same force, 
 with its induced motion changed in direction ; as in 
 the impingement of billiard balls; in the resistance of 
 water to the motion of a ship ; in the counterpoise of 
 two heavy bodies, where one descends with the same quan- 
 tity of motion with which the other ascends; in the 
 vibration of the pendulum, the rise being equal to the 
 fall ; in the rebound of a ball in proportion to the 
 strength of the impulse given. The law, therefore, as it 
 stands, affirms with some obscurity the doctrine of the inde- 
 pendent existence of force, of its transfer to other bodies in 
 whole or in part, and of the change of direction often in- 
 duced if it continue in the same body. In this point of view 
 the law stands, as has been said, as the basis of mechanical 
 philosophy, and rightly understood expresses a universal law 
 which applies to all motion in the universe ; Action pro- 
 ceeds from force, reaction proceeds from the same force. 
 The result of any degree of force is continued action. It 
 may be divided, giving two bodies equal and contrary action, 
 
 6 
 
62 OUTLINES OP A SYSTEM OF 
 
 or it may continue in the same body acting in a contrary 
 direction. The action of force is uniform ; its transfer and 
 line of direction contingent. 
 
 There is an unintelligibility in the doctrine of reaction as 
 usually explained. It is very difficult of statement in con- 
 formity with the present theories of motion and the causes of 
 motion. We turn to a philosophical treatise of rather ancient 
 date, and find these instances given : " When a man strikes 
 one hand against the other, the blow is felt equally by both 
 hands ; if you strike a glass bottle with a steel hammer, or 
 the hammer with the bottle, in either case the bottle will be 
 broken if the blow be sufficient ; if a stone be tied to a horse 
 by means of a rope, the horse in dragging the stone will 
 exert a degree of force equal to the resistance of the stone, 
 for the rope will equally pull the horse toward the stone, 
 and the stone toward the horse." But then, the error was 
 too palpable, and the writer destroys the law at once, 
 adding, " and in fact the stone will not follow the horse, 
 unless the power of the horse be greater than the power of 
 the stone." Indeed, there could be no motion under the 
 law as usually stated, for all action would be met with equal 
 resistance. It is however sometimes stated in such a man- 
 ner as to give the idea that force is increased by being com- 
 municated. Dr. Arnott, in his Elements of Physics, says, 
 " When any elastic body, as a billiard ball, strikes another 
 larger than itself and rebounds, it gives to that other, not 
 only all the motion which it originally possessed, but an ad- 
 ditional quantity, equal to that with which it recoils, owing 
 to the equal action in both directions of the repulsion or 
 spring which causes the recoil. When the difference of 
 size between the bodies is very great, the returning velocity 
 of the smaller is nearly as great as its advancing motion was, 
 
MECHANICAL PHILOSOPHY. 63 
 
 and it gives a momentum to the body struck, nearly double 
 of what it originally itself possessed. This phenomenon 
 constitutes the paradoxical case of an effect being greater 
 than its cause." These statements must always be under- 
 stood in conformity with the principle, that every degree of 
 force gives its definite amount of motion, though the quan- 
 tity of motion may appear different from acting on different 
 quantities of matter. 
 
 "We will, however, state the doctrine of resistance in the 
 words of Prof. Daniell, who is distinguished for accuracy in 
 the enunciation of his opinions. He says, " In lifting a lump 
 of iron or lead we are conscious of opposition, and conse- 
 quent exertion." Of course ; for the application of strength 
 animal force is always attended by effort, by exertion ; the 
 effort is not because the iron or lead resists, but because to 
 raise it requires the application of force for its rotation at 
 the higher level. He continues, " In drawing a bow, we 
 feel an opposing resistance which we denominate elasticity, 
 a gradually increasing opposition which our utmost force 
 may not be able to overcome." ..." If the opposition be sud- 
 denly withdrawn and the bow be allowed to act, on its 
 return the arrow will have a projectile force communicated 
 to it." All this is true. The muscles of the arm by force 
 separate the atoms composing the one side of the bow, and 
 press together the atoms on the other side of the bow. 
 When the action of the muscles ceases, the atoms of the bow 
 return to their normal position, and the force that disturbed 
 them is communicated to the arrow, which rushes forward, 
 gradually imparting its force to the air, till exhausted it falls 
 to the ground. Here there is no reaction whatever. But 
 we find in this instance a beautiful analogy between the 
 action of the bow and of the bent arm, in the will to 
 
64 OUTLINES OF A SYSTEM OF 
 
 straighten the arm, and in the will of nature to straighten 
 the bow. 
 
 The idea of reaction, as we have said, undoubtedly came 
 from the idea of resistance in the exertion of muscular force. 
 We cannot with the hand move a body without feeling what 
 is called reaction ; and probably the best instance that can 
 be given is the result of the action of standing in one boat 
 and pushing off another boat, in which case resistance is felt, 
 and the reaction gives the contrary equal backward motion. 
 But it is most readily explained. The action of the body in 
 this case is like that of a bent spring with one end in each boat, 
 and of course it acts equally on both in opposite directions. 
 
 The author just referred to asks this question, the true 
 solution of which more fully explains the action of the spring, 
 though his answer is obscure : " Is a spring stretched by 
 the sum of the forces of the two arms, or by one only ? " 
 This is his reply : " Let one end of the spring be attached 
 to a fixed support, and it will be found that the same effort 
 of one arm, or one weight, will stretch it to the same amount 
 as before ; the force of the other arm or other weight only 
 measured the resistance, the amount of reaction, which 
 necessarily accompanies the action, and which is now borne 
 by the support. " We reply, there is no reaction whatever ; 
 the needed force, whether from weight, from one arm, or 
 from two arms, is supplied. A given degree, a measurable, 
 determinate quantity of force must be applied whenever and 
 however the spring be bent ; but this force must be either 
 applied to both ends, or one end must be secured and all the 
 force applied to the other end. These are the conditions 
 on which the spring is bent, or on which the force is applied 
 to the atoms of the spring ; without these conditions, if force 
 be applied it will move the spring upward, downward, or 
 
MECHANICAL PHILOSOPHY. 65 
 
 sidewise, as a whole. Here "resistance" is the condition 
 on which the spring can be bent. The strings of the harp 
 on the application of force can be moved without being 
 strung upon the instrument, but their melody of vibration 
 comes from their tension. The arm not " resisted " at the 
 shoulder could move no weight. 
 
 It is said that the blow of a hammer on an anvil is accom- 
 panied by reaction. We answer, A part of the force which 
 gives the blow is not transferred, but relifts the hammer, 
 and, if the blow be unskilfully given, will declare its presence 
 by a sharp vibration in the hand which holds it ; a part is 
 transferred to the anvil which vibrates the anvil, and the 
 force spreading in all directions vibrates the air with a 
 ringing sound. Let, however, the blow of the hammer fall 
 upon heated iron, then the hammer is not relifted, and 
 the force is mainly transferred to the iron, a small portion 
 only escaping, giving a heavy vibration to the air. A most 
 striking illustration of the distinction between absorbed 
 force and transferred force is this : If a string be pulled with 
 great force and it breaks, "reaction" will cause him who 
 pulls it to fall, the unused force returns ; let him draw 
 wire through a wire plate, expending the same force, when 
 the end slips through the plate, he will feel no reaction, no 
 shock, but will stand firm, because the force is safely deposit- 
 ed among the particles of the extended iron. We remember 
 repeating the experiment with wonder at the different 
 results, the very results which might have been affirmed 
 without the test of experiment, had we understood the laws 
 of force. 
 
 The motion of a steamboat is generally considered as 
 depending on reaction. The paddles of the boat strike the 
 water, by the reaction of which, it is said, the boat is pro- 
 
 6* 
 
66 OUTLINES OF A SYSTEM OF 
 
 pelled. In fact the common statements with regard to 
 reaction and resistance have thrown obscurity over the 
 subject. We will trace out the action of the wheel of the 
 steamer, in the hope that we shall find the truth, and the 
 truth in this one instance will cover the whole ground. 
 
 It is the force of the steam which by proper mechan- 
 ical appliances causes the wheel to revolve. If the wheel 
 turned in a vacuum, all the force of the steam would be lost 
 for propulsion, exhausting itself in whirling the wheel ; if 
 the paddles revolved against an immovable body, like a 
 ledge of granite, all the force of the steam would give pro- 
 pulsion to the boat ; if the wheel revolve in water, a part 
 of the force will give a backward motion to the water, and 
 the residue will give propulsion to the boat. In neither 
 case does reaction move the boat, but the force of the 
 steam ; for the solid granite stands firm without force or 
 motion, and of the water, neither the portion which is 
 unmoved, nor the portion which moves backward, has the 
 least effect in communicating onward motion to the boat. 
 It might as well be said that the water at the bows propels 
 the vessel by its resistance, as that the water at the wheel 
 does ; or that the iron track of the railroad gives propulsion 
 to the locomotive, as that the track of the wheel in the 
 water moves the boat. The force which impels the boat is 
 from the expansion of steam, the water only giving direction 
 to the motion of this force. 
 
 The force of the steam as generated is expansive, acting 
 in every direction ; it could be let off safely through the 
 pipes into the air, thus wasting its strength, or it could be 
 made to act on any part of the vessel, breaking her into 
 pieces. To be useful in propelling the boat, it ntust have 
 one line of direction given to it. This direction is relative 
 
MECHANICAL PHILOSOPHY. 67 
 
 to the earth. It must, therefore, in propulsion, have refer- 
 ence to something external, otherwise the " two ends of the 
 spring" would act in the ship, giving to its parts motion in 
 opposite directions ; to give to the boat a motion relative 
 to the earth, one end must be acting on matter outside of the 
 boat. The action of the wheel on immovable granite is 
 the securing of one end of the spring, so that its whole 
 force may act in giving motion to the boat with the other 
 end ; and, as we observed, if the wheel revolved against an 
 immovable body, the whole force would be used for propul- 
 sion. Acting against water, so far as the water is moved, 
 the force is lost ; so far as it is unmoved, or resists being put 
 in motion, the force of steam is of use for propulsion. 
 A familiar illustration of this is, that in rowing a boat near 
 the shore, if the oar touches the rocks, much more force 
 adheres to the boat shooting her ahead, since none of the 
 oarsman's strength is wasted in giving motion to the water. 
 
 If we place the hand in water, moving it slowly, a slight 
 resistance will be felt, and the resistance will increase in pro- 
 portion to the velocity of the motion of the hand. It is said 
 that a ball of iron will strike the water more forcibly than a 
 ball of cork of the same size, and be more resisted than the 
 cork, though both move towards the water with the same ve- 
 locity. Therefore it is inferred that reaction is in propor- 
 tion to momentum, momentum being the product of the 
 velocity by the weight. 
 
 It is not so. The resistance to a body impinging the 
 water is in proportion, not to its momentum, but to the 
 quantity of the water to be moved out of the way, and the 
 velocity with which it is to be moved away. A short ship, 
 say fifty feet in length, with a momentum represented by 
 100, sails five miles an hour, and a ship one hundred feet 
 
68 OUTLINES OF A SYSTEM OF 
 
 in length moves, with the same breeze and proportional 
 canvas, with a momentum of 200. The resistance increas- 
 ing with the momentum, with the same force in proportion to 
 the mass, the long ship under the theory would sail only five 
 miles an hour. Practically, however, the longer the ship 
 driven by the same proportional force, the greater the 
 velocity ; for the short ship with the momentum 100, loses 
 say 10 of her force in moving away the water from her 
 bows, in other words, in opening her path. In the long ship, 
 moved with the momentum 200, it still requires only 10 
 for this purpose, leaving 190 for propulsion, which is 95 
 for each of the two halves. The long ship has then -fa more 
 force for propulsion. The per centage of force needed to 
 open the path is less in the long than in the short ship. 
 
 Thus resistance to the vessel is not measured by the 
 " momentum " of the vessel, but by the quantity of water to 
 be moved, and the speed with which it is moved away. 
 There is, in fact, no resistance in the case whatever ; but a 
 part of the force of propulsion is necessarily used in removing 
 the water from the track. There are other circumstances 
 which modify this loss of force, for instance, the shape of the 
 bows. If the shape be such that the water is elevated, 
 there is a loss of force to raise this water above the level. 
 The form of the ship should be such as to establish a current 
 from the bows to the stern. The less the surface of the 
 water is disturbed, the better. For this reason a body 
 wholly submerged is less impeded ; for the path opened is 
 but a circulation of the water from one end to the other of 
 the moving body. If the body plunged be suddenly moved 
 under water, before the current is established, the water 
 will rise in a wave at the surface ; after the current is es- 
 tablished by the moving body, the surface is at rest. When 
 
MECHANICAL PHILOSOPHY. t>9 
 
 the wave was raised, force was supplied for its higher 
 rotation. 
 
 It appears, therefore, that what is called the resistance of 
 the water to the propelled vessel, comes not from reaction, 
 but is the loss of force in establishing the current by which 
 her path is opened. 
 
 In the preceding statements the word momentum has been 
 employed in conformity to the usual language. As was before 
 observed, momentum is the degree of force present in action 
 upon the body. It is the energy or strength of the motion. 
 The intensity of force is measurable by the velocity it im- 
 parts ; but as it requires more or less force according to the 
 weight of the body, to move a body with a given velocity, in 
 ascertaining the present force of a body in motion, its weight 
 is one of the elements of the calculation. Momentum is 
 therefore the force which moves the body, that which it 
 will impart when the motion is arrested. It is simply force, 
 and the use of the word momentum is not only unnecessary, 
 but it leads to a confusion of ideas to employ two words to 
 express the same thing. 
 
 If a bullet be discharged from a gun through a door left 
 ajar, it will pass through the wood, giving no motion to thOj 
 door. In gunnery, cannon balls, to do the most injury 
 to a ship, should be fired with small charges of powder, that 
 they may not pass through the ship, but transfer their mo- 
 tion to it. In these cases, reaction increases with the les- 
 sening of the force, that is, if the ball pass through the ship, 
 it does not injure the ship so much as if the motion of the 
 ball be arrested, and its force transferred to the work of 
 destruction. The gun recoils proportionally to the force 
 of the explosion, of course j for explosive mixtures act in 
 all directions, 
 
70 OUTLINES OF A SYSTEM OF 
 
 The doctrine of vis inertias asks a passing comment. It 
 is inferred from the first law of motion. Bodies in motion 
 continue in motion from the inertia of motion ; bodies at 
 rest continue at rest from the inertia of rest ; that is, bodies 
 which move do move, bodies at rest are at rest. This is all. 
 The idea receives some coloring from two facts. First, the 
 progressive motion of a mass is in proportion to the force 
 impressed, and takes place after a lapse of time from the 
 application of the force to the atoms of the body. There 
 is needed time for the force to be diffused among the atoms 
 by atomic motion, before consentaneous or progressive motion 
 is induced. The other fact is, that in most cases force in 
 moving bodies is gradually applied. 
 
 Thus a bullet slowly moving will enter the water; for 
 it can, as it were, await the tardy resolution of the atoms of 
 the water into progressive motion to give it place. But the 
 bullet from the gun is deflected. Its velocity is so great 
 that it cannot transfer its force ; for it would take many 
 instants for the particles of water, moving with the same 
 velocity with the bullet, to travel through their atomic space, 
 and to induce progressive motion of the column necessary 
 io be moved for the passage of the bullet through the water. 
 
 We now come to the consideration of another principle, 
 which is often referred to in the explanation of the mechan- 
 ical powers. It is this : The loss of time is the gain of 
 power ; and, conversely, the gain of time is the loss of 
 power. It is not so. Why, let us ask, are there in the 
 text-books of mechanical philosophy assertions like this : 
 " Time is an important element of force " ? Time has no 
 reference whatever to force, or to motion consequent upon the 
 force applied. It can neither make nor destroy it. It can- 
 not increase or diminish it. A body with the same present 
 
MECHANICAL PHILOSOPHY. 71 
 
 force moves on forever with an uniform motion. Time can 
 never change the quantity, quality, or direction of motion. 
 Time is a succession of events. It is itself measured by 
 motion, by the harmonic uniform motion of the spheres. 
 We measure motion by time indirectly ; its direct measure 
 is the motion of the earth. Velocity is more conveniently 
 applied to the artificial divisions of time than to the earth's 
 motion. It is, perhaps, better for common purposes to say 
 that a body moves so many miles an hour, than to say that 
 it moves so many miles while the earth moves one twenty- 
 fourth of a rotation. 
 
 But the doctrine like that of action and reaction, and of 
 vis inertioe, has a coloring or semblance of truth from the 
 misconception of facts. In two ways time has an apparent 
 connection with force, as if time increased force. 
 
 First ; animal or muscular force is produced by the ani- 
 mal by a succession of efforts. It is generated gradually, 
 and of course imparted gradually. By time the force is 
 increased or added to. Time does not increase power ; but 
 the muscles can supply more force in five minutes than in 
 one minute. This idea is fully illustrated by the inclined 
 plane. A horse, in dragging up a weight, has more time 
 to produce the required force ; but when the load is ele- 
 vated, he has imparted just that degree of force which is 
 required to elevate the weight directly, at once, verti- 
 cally. The mechanical power of the inclined plane enables 
 the animal to do by successive efforts what he could 
 not do at once. He cannot raise the weight at once ; he 
 can raise the weight in time. A man cannot raise by one 
 effort a ton of iron ten feet, but in an hour he can furnish 
 the necessary force. Yet, it is said in a work on mechanics, 
 that it requires no force to move a body horizontally, full 
 
72 OUTLINES OF A SYSTEM OF 
 
 force to raise it vertically, and that the gain of power by the 
 inclined plane is in simple proportion to the angle it makes 
 with the horizon ! 
 
 Secondly ; another misconception is of the law of falling 
 bodies. The force of the falling stone, it is commonly said, 
 increases according to the square of the time of descent. 
 The force increases not with time, but with every line of 
 descent. The descending body has, proportionally to its 
 change of level, an increase of spare force, of force 
 unused at its lower level of rotation. The greater the fall, 
 the more the force. 
 
 Thus in the use of animal strength, and in the use of the 
 force of the falling body there is, not an increase of force by 
 time, but an addition to the force received in time. A 
 man's power of labor is measured by time ; the power of the 
 waterfall is measured by the space of descent, or for con- 
 venience' sake, by the time it falls, as the space and time 
 are in one fixed ratio. 
 
 So simple is the explanation of the philosophy of the me- 
 chanical powers, that it is surprising that the subject should 
 ever have been deemed intricate, or that so much mathe- 
 matical labor should have been wasted on it. To under- 
 stand the lever, and, that understood, all the mechanical 
 powers are understood, does not require one to read 
 Archimedes' mathematical demonstration, nor to understand 
 the laws of statics, dynamics, virtual velocities, equilibrium 
 of forces, and centres of gravity. Let one idea be present 
 to the mind, and there can be no misconception. The force 
 applied is the force that produces the result ; time will not 
 increase or diminish it, it ever remains of one intensity, 
 capable of producing only one degree of motion ; no lapse of 
 time, no mechanical skill can change its nature or degree. 
 
MECHANICAL PHILOSOPHY. 73 
 
 Without reference to loss by friction, it may be transferred 
 through pulleys, levers, wheels, over inclined planes, when- 
 ever needed, and when used at the end of the line there is 
 only, and just that force which was at first applied. It will 
 there produce the same quantity of motion, neither more 
 nor less, that its direct use would have produced without the 
 intervention of the machinery. If by the lever one pound 
 raises two pounds, the two pounds will be moved half as far ; 
 if a man raise a ton by means of a pully, he has put forth 
 just the strength that would be required to raise a ton to 
 the same height without the pully. His gain has been the 
 time given for him to produce and apply the strength. He 
 could not lift a cord of wood at once, but log by log he can 
 supply the needed force for piling it. If a smaller wheel . 
 turn a larger one more slowly, there is still the same degree 
 of motion in the larger wheel that was in the smaller ; if 
 the larger turn the smaller, there is still the same motion 
 in proportion to the quantity of matter. It requires one 
 degree of force to give one quantity of motion ; a given 
 force can do neither more nor less. This is rigorously true, 
 and, if it be understood, there is no mystery about the me- 
 chanical powers. If there be a gain of power, it is distinctly 
 traceable to the gradual addition of force from animal 
 strength, or from the increasing force of a descending body. 
 The measurement of these by time has led to the confusion 
 thrown over the subject by the doctrine, that there is a gain 
 or loss of force by time. It will not be necessary to remark 
 particularly on either class of the mechanical powers, as it 
 is believed that this general statement covers the whole 
 ground. 
 
 The next supposed force to be examined is the centrifugal 
 force, or the tendency of bodies moving in curved lines to 
 7 
 
74 OUTLINES OF A SYSTEM OF 
 
 assume a rectilinear motion. It is not exactly a force, 
 but a tendency of the moving mass not to move as it is 
 moving. In the Philosophy of the Inductive Sciences , we 
 find the following explanation of the character of this ten- 
 dency. " The centrifugal force is not a distinct force in a 
 strict sense, but only a certain result of the first law of 
 motion, and is measured by the portion of centripetal force 
 which counteracts it." " The projectile force is a hypo- 
 thetical impulse, which may at some former period have 
 caused the motion to begin, while the central force, gravita- 
 tion, is an actual force which must act continuously, and 
 during the whole time of motion, in order that the motion 
 may go on in the curve." 
 
 If we had no doubt of the truth of the theories which 
 relate to the motions of the spheres, the reading of such 
 passages would suggest a doubt. There is an obscurity of 
 language, not arising from the want of power of expression, 
 for no man has more power than this author, but because 
 there was no distinct idea to be conveyed. In the first place, 
 centrifugal force is not a force, but a result ; not being a 
 force, it is still measured by another force. Then, the 
 force which is not a force is counteracted, of course it is 
 destroyed, it no longer acts. This verbal criticism is made 
 only for the argument, that doctrines feebly expressed by 
 strong men are of doubtful soundness. 
 
 It is supposed that the moon, for instance, received 
 originally an impulse of motion in a straight line, but that, 
 being constantly acted upon by the attraction of the earth, 
 the straight line is changed into the curve ; that the attrac- 
 tion of the earth which would, unchecked, draw her to the 
 earth, is opposed by the centrifugal force ; and that the 
 moon, under the influence of forces acting in opposite direc- 
 
MECHANICAL PHILOSOPHY. 75 
 
 tions, is held in her orbitual course, the original impulse 
 giving the motion. 
 
 But as the moon's orbit is elliptical, she is at times com- 
 paratively nearer to, and at times further from the earth. 
 Of course, in her changing distance, the centripetal and 
 centrifugal forces vary in intensity. The earth attracts 
 less or more according to distance, and the counteracting 
 force changes relatively ; they preserve an equilibrium. It 
 cannot be that the force of opposition can remain with an 
 equal intensity, when the force of attraction is continually 
 changing. They therefore change proportionally, or to the 
 same degree, so that the moon is guided in her course by 
 forces perfectly elastic. 
 
 Again ; if the original impulse of the moon's motion were 
 an impulse of rectilinear motion, and the attraction of the 
 earth acts in a straight line to her centre, how from two 
 forces acting at right angles is the curved line of motion 
 produced ? An original impulse in a straight line of direct- 
 ion, and another impulse in a straight line at a right angle 
 with it, would ever and invariably produce a straight line of 
 motion at the mean distance, half way between the two 
 lines of impulse. If gravitation changed the moon's motion, 
 the moon must necessarily be brought thereby nearer to the 
 earth ; if it act on the moon impelled in a straight line, the 
 resulting motion would be a mean direction, lessening the 
 distance between the attracting and attracted bodies. Even 
 Newton, at an early period of his speculations, held the 
 opinion that the result of attraction on the impelling force 
 would be motion in a kind of spiral. 
 
 That the orbit of the moon could be formed by the action 
 of the two forces, has been nominally proved from the case 
 of the cannon ball, which under the joint force of projection 
 
76 OUTLINES OF A SYSTEM OF 
 
 and gravitation describes a curve. But the case is not an 
 analogous one. The curve of the projectile is occasioned 
 by the regular decrease of the force of impulse. Its onward 
 force is gradually lost by the resistance of the atmosphere, 
 and thus "gravitation" brings the path described into a 
 curve. In order for the attraction of the earth to give a curve 
 to the orbit of the moon, the impulse of the moon must be 
 gradually lessened by some retarding medium, as the can- 
 non ball is retarded by its passage through the air, whence 
 would result a spiral curve gradually bringing the moon to 
 the earth. But never can the impulse in two directions of 
 the rectilinear force result in a curve. We know that the re- 
 verse is mathematically proved, and that the nature of the 
 curve which would be produced is pointed out ; but the 
 mathematics by which this is done, is of a peculiar kind 
 introduced with the theory of gravitation, being rendered 
 necessary by this theory. 
 
 What gives the elliptical form of orbit, for instance, of 
 the comet, which, at one time widens its path in the broad 
 expanse of almost limitless space, and then narrowing its 
 orbit, almost brushes in its rapid flight the face of the sun ? 
 It is not force of motion ; for this force acts according to the 
 law of the area described in every part of the orbit. It is 
 not attraction ; for attraction merely holds its own, increas- 
 ing or diminishing according to distance. Nor yet is it 
 centrifugal force ; for this follows, and is measured by, gravi- 
 tation. It is not space ; for there is no grooved channel or 
 marked track through its vastness. A sphere, perfectly a 
 sphere, each atom of which was moved with equal force, 
 would necessarily describe a circle. May it not be that it 
 is the shape of the revolving body ; that, if the shape of this 
 world, for instance, is given, the ellipsis of her orbit may be 
 

 MECHANICAL PHILOSOPHY. 77 
 
 determined ; and that, if we knew the form of the comet, 
 its eccentricity of path could be understood. 
 
 The idea of centrifugal force grows out of a trivial, and 
 perhaps misunderstood fact, and is invariably illustrated by 
 it. We allude, of course, to the action of the sling. From 
 the hand proceeds the impulse of motion, the string is the 
 gravitating power, or that which by its tension measures this 
 power, and the tendency of the stone to fly off in a tangent 
 represents the centrifugal force. It is unquestionably the 
 tendency of the stone to escape, and, if the string were to 
 break or be let slip, the stone would no longer continue to 
 move in the same circle, but the impressed force would give 
 it another direction of motion. The force of motion of the 
 stone is from the centre. There is nothing to give the 
 stone its circular movement except the string ; that broken, 
 the impressed force gives the stone a curved motion in 
 another direction. 
 
 So far is this action from being analogous to the motion 
 of the nioon, that it is the very reverse. The stone from 
 the sling receives force acting in a line of direction from the 
 centre ; the moon receives from the centre of her orbit an 
 impulse toward the centre. It is not a fortunate illustra- 
 tion to compare the effect of an impulse away from the 
 centre, to an impulse affecting the body and drawing it 
 toward the centre. 
 
 Centrifugal force, too, is often illustrated by the neces- 
 sity which a man finds in running round a small circle, of 
 leaning inwards toward the centre, "to counteract the cen- 
 trifugal force." But we will quote a contrary opinion : 
 c< Let any man move in a circular or elliptical line described 
 or marked out to him, and he will find no tendency in him- 
 self either to the centre or from the centre. If he attempt 
 
 7* 
 
78 OUTLINES OF A SYSTEM OF 
 
 the motion with great velocity, or if he do it carelessly and 
 inattentively, he may go out of the line either from the 
 centre or towards it ; but this is to be ascribed not to the 
 nature of the motion but to our infirmity, or perhaps to the 
 animal form, which is more fitted for progressive motion in 
 a right line than for any kind of curvilinear motion." 
 Thus says Lord Monboddo, and proves that philosophers are 
 not agreed among themselves concerning a fact, which is 
 assumed as a " standard example " of their mechanical 
 doctrines. However it may be with a man running round 
 in a circle, we feel quite sure that a revolving sphere would 
 not have to lean inward to prevent its falling outward, or to 
 lean outward to prevent its falling inward. 
 
 The action of the governor of the steam engine has also 
 been referred to, in order to illustrate centrifugal force. 
 The two heavy balls are so suspended that when not revolv- 
 ing they hang motionless ; endued with activity in propor- 
 tion to the velocity of their revolution, they rise, and describe 
 wider and wider revolutions. The reason of the rise of 
 these balls is the force communicated to them, from which 
 they take a higher level of rotation, a beautiful illustra- 
 tion of the views we present. They could not thus rise 
 from the action of centrifugal force, were there any centrifu- 
 gal force ; it impels, if it impel at all, from the centre. 
 
 How could the moon be held in her orbit, if centrifugal 
 force acted in any* : other direction than the direction oppo- 
 site to the force of gravitation, which is to counteract it ? 
 
 The breaking of the too swiftly revolving wheel is another 
 illustration of the centrifugal force, which keeps the planets 
 from responding to the attraction of gravitation. But the 
 application of force to turn the wheel is at the centre, as 
 in the sling it is from within outward. The central part 
 
MECHANICAL PHILOSOPHY. 79 
 
 of the wheel as truly impels the circumference, as the 
 crank or rod impels the centre. There is motion induced 
 under the condition, that the cohesion of all the matter 
 in motion will bear the force applied at the centre. If too 
 much force be applied, the crank or the wheel may break. 
 The greatest force required is at the circumference, while 
 the force is applied at the point the furthest removed. 
 Every practical mechanic knows that there is no danger of 
 a wheel's breaking if the motive force be applied to the cir- 
 cumference. But nature does not so unskilfully apply her 
 motive power. Her force for revolution or rotation is 
 present with every atom. It is equally diffused through the 
 whole mass, every particle retaining its proportional motive 
 power according to the orbit to be described ; each moves 
 of itself, and from its own energy ; one does not push, draw, 
 or impel another. There is for this reason harmony of 
 motion, all things moving according to the order of nature. 
 Those who require a balance of forces, conflicting powers, 
 those who compare the motion of the spheres to a school- 
 boy's sling, or to the dizzying whirl of a man running in a 
 circle, seem to degrade the mechanism of the heavens below 
 the results of human ingenuity. 
 
 We pass from centrifugal force to its opposite, centripetal 
 or attractive force, gravitation. 
 
 It may be well to give an outline of the theory as pre- 
 sented by those who have the most unshaken confidence in 
 its truth. The theory of universal gravitation asserts, 
 that the force, by which the different planets are attracted 
 to the sun, is in the inverse proportion of the squares of 
 their distances, and that the force, by which the same planet 
 is attracted to the sun in different parts of its orbit, is also 
 in the inverse proportion of the squares of its distances ; 
 
80 OUTLINES OF A SYSTEM OP 
 
 that the earth also exerts a similar force on the moon, and 
 that this force is identical with the force of gravity ; that 
 bodies thus act on other bodies besides those which revolve 
 round them ; that thus the sun exerts such a force on the 
 moon, and that the planets exert such forces on one another ; 
 further, that this force, thus generally exerted by the entire 
 masses of the sun, earth, and planets, results from the 
 attraction of each particle of these masses, which attraction 
 follows the above law, and belongs to all matter alike ; also, 
 that this attraction, operating on the " hypothetical impulse 
 of motion," gives its spheroidal form to the earth, and their 
 elliptical form to the orbits of the heavenly bodies. 
 
 This theory has been a settled doctrine of philosophy for 
 nearly two centuries, and generally, if not universally, it is 
 deemed an established truth. It seems to have passed away 
 from examination, to be laid aside as that which need never 
 again be the subject of thought. It is spoken of as ascer- 
 tained ; and its discovery and extended application are 
 considered as among the most glorious achievements of the 
 human intellect. 
 
 Thus it will be almost impossible, even if the theory be 
 not founded in truth, to bring the minds of men to its re- 
 examination. It has become associated with the universe 
 from its most enlarged to its most attenuated parts. The 
 attempt to substitute other theories, to assign other laws of 
 force, may be deemed the wandering of an erratic mind, 
 or the presumption of an ignorant man. But this research 
 was commenced without reference to the public, and the 
 results are presented, not presumptuously, but firmly, not 
 with the belief that we have fully developed the truth, 
 that all our views are sound, that no mistakes are made, 
 but with the conviction that our speculations are founded 
 
MECHANICAL PHILOSOPHY. 81 
 
 upon principles that fully deserve attention and examination. 
 We appeal to those who believe that there is yet hope of 
 progress in philosophy. 
 
 Attraction, as coming under human observation, is mainly 
 believed on considerations derived from the fall of bodies to 
 the earth, and from their supposed weight or pressure when 
 at rest. This is the foundation of the theory. All else 
 is assumption or deduction. The mutual attraction of 
 different masses at the surface of the earth is supposed to 
 corroborate the theory ; but from the utter impossibility of 
 measuring this slight action, or even of ascertaining if there 
 be any, the mutual attraction of the minor masses being 
 overwhelmed by the immense comparative mass of the 
 earth, it is a proof about as conclusive as that the sun 
 shines because a fixed star twinkles. The doctrine of at- 
 traction, therefore, rests on the observed fact that bodies 
 unsupported fall to the earth. 
 
 If, therefore, the descent of a body can be fully accounted 
 for by the spare force of rotation at a lower level, and its 
 weight or pressure by the fact that it requires force to lift 
 it up to a higher level, the reason on which the theory of 
 gravitation stands is taken away. 
 
 The law of gravitation is not needed for the motion of the 
 heavenly bodies. There is more truth to nature, there is 
 more simplicity and beauty in the idea that the force of the 
 revolving body is within itself ; that its curvilinear motion is 
 its natural motion ; that it goes round in its orbit without 
 needing the guidance and direction of central and tangential 
 forces ; that it can be trusted to the unerring energy 
 imparted to it from the beginning. It needs no great pre- 
 sumption thus to affirm ; for by ancient philosophers, and 
 in more recent times by Copernicus, Galileo, Kepler, Des 
 
82 OUTLINES "OF A SYSTEM OF 
 
 Cartes, it was believed that circular motion was the natural 
 motion. 
 
 Nor is the general acceptation of a theory any proof that 
 it is the most true and most perfect theory that will ever be 
 presented. How long endured the Ptolemaic system of 
 astronomy, how firm was the belief of men in its truth ! 
 Those who first questioned it, those who first doubted that 
 the sun revolved around the earth, were not only deemed 
 unsound in reason, but " diabolical and wicked," and were 
 visited by the vengeance of the offended good sense of 
 man. Extensive, too, was the sway of the theory of Des 
 Cartes, which preceded the theory of gravitation. The 
 Cartesian hypothesis, representing the worlds as moved by 
 vortices of revolving matter, and the fall of bodies as 
 motion downward by the decrease of the range of the vor- 
 tex, they sinking to the lowest part of the whirlpool, held 
 for a while an even contest with the hypothesis of gravita- 
 tion, the battle hanging long with doubtful issue. Because 
 it was decided at last in favor of the Newtonian school, is it 
 to be supposed that the speculations of that truly great man, 
 Des Cartes, were all absurd, that he affirmed no truth, 
 that Newton was right in all his affirmations, and that 
 the power of progress expired with his life ? How great 
 were Galileo, Copernicus, Leibnitz, Kepler ! Yet who takes 
 for granted all that they asserted ? To see truth fitfully, 
 through the obscurity of error, is the most that can be hoped 
 for by any man. or can be claimed as the result of the labors 
 of any philosopher. 
 
 Among the minds distinguished as far surpassing in 
 power the range of ordinary intellects, was that of Kepler. 
 He seemed, on some points at least, to have an intuitive per- 
 ception of truth, and his discoveries have led to extended 
 
MECHANICAL PHILOSOPHY. 83 
 
 practical results. His determinations of the laws of plan- 
 etary motion are, and must ever continue to be, the basis of 
 knowledge in astronomy. Yet even he believed that the 
 earth was an animal, and many of his other ideas create a 
 smile, they appear so fanciful and absurd ; but fanciful 
 and absurd because time and further observation have 
 refuted them. 
 
 It is no evidence of a want of reverence for the 
 great, that we believe and assert that no individual is 
 without error or has attained the whole truth ; that no 
 authority, however great, should determine and settle every 
 principle in philosophy. " There were giants in those 
 days ;" but so long as the race of man exists there will be 
 strength. 
 
 " Why," said a very great man, far back in the ages of 
 time, u why is it that neither very small nor very large 
 bodies go far when we throw them, but in order that this 
 may happen the thing thrown must have a certain propor- 
 tion to the agent which throws it ? Is it that the thing 
 which is thrown must react against the thing which pushes 
 it ; and that a body so large as not to yield at all, or so 
 small as to yield entirely and not to react, produces no 
 throw or push?" Should the human mind have rested 
 upon philosophy like this ? By no means. The theories of 
 philosophy are not truth, but monuments set up to mark the 
 progress of man in his search for truth, guides in the 
 path which leads to the truth. We should read with rever- 
 ence for the great minds of olden times, while rejoicing in 
 the advance which present opinions indicate ; we should 
 read present opinions in the belief that they also will serve 
 future generations to mark a continued and accelerated 
 progress ; we should read with respect for those who have 
 
84 OUTLINES OP A SYSTEM OF 
 
 faithfully discharged their trusts, and with confidence that 
 those who are yet to do work upon the earth, will do it even 
 more successfully, for having the vantage ground of former 
 attainments, the highest reach of the minds of the greatest 
 men of one century furnishing the elements of thought to 
 the succeeding age. 
 
 Those who reverence Newton should show their reverence 
 by imitating him in his unwearied and eager search for new 
 truth. He was not satisfied with philosophy as he found it ; 
 but, taking the floating theories of his time, he employed his 
 immense intellect in giving them system, character, definite- 
 ness, so that his philosophy, partaking of the vigor of his 
 mind, has so long held dominion over the world. Though 
 his name is most intimately associated in the general mind 
 with the theory of gravitation, his labors in this depart- 
 ment used but a small portion of his energy. Every sub- 
 ject in the vast range of subjects to which he directed 
 his attention retains the marks of his strength. He is 
 often thought of as a mere mathematician, verifying the 
 ideas of others. Far from it. His originality of mind 
 equalled his mathematical exactness of conception. How 
 eagerly did he seize upon every new truth, how ready was 
 his mind for progress ! The contemplation of such a char- 
 acter should prevent us from ever remaining satisfied with 
 ideas to which the least doubt can be attached. 
 
 
CHAPTER V. 
 
 " IN THE CONSTANT OSCILLATION OP THE HUMAN MIND BETWEEN 
 IDEAS AND FACTS, AFTER HAVING FOR A MOMENT TOUCHED THE 
 LATTER, IT SEEMS TO SWING BACK MORE IMPETUOUSLY TO THE 
 
 FORMER." Whewell 
 
 WE pass from the examination of the very minute and of 
 the far-extended, to the common facts of our daily observa- 
 tion ; gladly throwing down the telescope and microscope, 
 we will look with the naked eye at nature in the ordinary 
 range of vision. 
 
 Were we to select one class of facts to illustrate the ideas 
 we present, and to disprove the attraction of matter, it 
 would be that which relates to oscillatory motion, the 
 action of the pendulum and kindred movements. 
 
 The swing of a pendulum, increasing in velocity in pro- 
 portion to the decrease of distance from the centre of oscil- 
 lation, the force of its motion being measurable by the area 
 of the circle of which it describes a segment, shows that the 
 nature of force is the same, however its energies may 
 operate. It brings to the mind the relative speed of the 
 planets, increasing as the diameter of their orbits diminishes. 
 Its regular beats mark time with the same precision as 
 does the harmonic motion of the heavenly bodies. It is, 
 therefore, a free, unrestrained movement, showing the laws 
 of force, and had it been rightly understood, the laws which 
 8 
 
86 OULTINES OF A SYSTEM OF 
 
 regulate the planetary movements might have been distinctly 
 inferred from it. " We feel," says Bailly, in his History of 
 Astronomy, " that nature is very simple in her operations ; 
 the positions and motions of the planets offer at first sight 
 the appearance of intricacy, but the principle which impels 
 them has a naturalness and simplicity like the character of 
 truth ; " and this principle has application not only to them, 
 but to all natural and unrestrained motion. Thus in the 
 pendulum, its orbit prescribed and a uniform force of impulse 
 given, motion ensues, invariable, equal, measured by the 
 area described. 
 
 A pendulum beating seconds does not change as to time 
 of vibration with the addition or subtraction of weight, nor 
 with a stronger or weaker impulse given to it ; the weight of 
 the mass moved and the length of the sweep do not change 
 the time, if the same length of rod is retained. The force 
 of motion is ever in proportion to the mass, and the stronger 
 impulse only increases the range of motion with an increase 
 of velocity that gives the equal time. The impulse lifts it 
 higher and it falls with greater rapidity, and the fall both 
 in distance and velocity determines the succeeding rise. It 
 is evident, therefore, that this result is produced by the 
 same principle which occasions the fall of bodies to the 
 earth ; for the downward force is just the force of a body 
 falling vertically the same distance, and the rise is also the 
 same both in relation to distance and velocity. It is the 
 same principle which causes the rise and fall of a stone 
 thrown into the air, to be in equal times. How can this 
 equal rise and fall of the pendulum be explained on the 
 theory of gravitation ? Where is the reference to the centre 
 of attraction, where the gravitating power ? How is it 
 that the power drawing to the earth draws and repels 
 
MECHANICAL PHILOSOPHY. 
 
 equally ? The rise is unquestionably a continuation of the 
 same motion as the fall, proving that the force has no more 
 reference to a downward than to an upward attraction. 
 
 Galileo first called attention to the fact that in the case 
 of a stone swung by a string, the time of its rise was equal 
 to the time of its fall without reference to the path or orbit 
 of its rise ; thus pointing to the truth that oscillation is but 
 the transfer and retransfer of the force of rotation, and that, 
 consequently, the force disengaged by the fall is the force 
 which occasions the rise. The force is produced by the 
 descent, and is absorbed by the ascent ; it is in proportion 
 to the degree of descent, and is necessary for the same de- 
 gree of ascent ; the degree of force is proportional to the 
 change of level, one mean level being ever preserved in all 
 oscillation. Therefore, the cause of oscillation is to be 
 referred to the moving body and not to the earth. 
 
 We repeat the idea ; the force by which the oscillating 
 body moves is the force disengaged from rotation by the 
 decrease of the level of rotation. It is the unseen force by 
 which all things move in their diurnal round, for a moment 
 becoming visible in the curve of the pendulum, as the un- 
 seen motes floating in the air show themselves for an instant 
 in passing through the beams of the sun. 
 
 From the view we have taken it will be perceived, that as 
 the pendulum preserves one mean level, and as its force of 
 descent is, as it were, annihilated by its ascent, it can neither 
 communicate force, nor be the source of any motive power. 
 We can also understand the manner in which the force of 
 impulse acts ; it gives the elevation by the descent from 
 which force is produced. Practically, to continue the oscil- 
 lation of the pendulum, force of impulse, as by the weight of 
 the clock, must be added continually ; for a single impulse of 
 
88 OUTLINES OF A SYSTEM OP 
 
 elevation is soon lost by friction, and by the force taken to 
 move away the air from the path of the vibrating mass. In a 
 vacuum and without friction, the pendulum would continue 
 to act without a renewal of the impulse. To understand 
 oscillation, we should separate in our minds the cause of 
 oscillation, the transfer of rotative force to other motion 
 and its reapplication to rotation, from the impulse which 
 first elevates the mass to the position from which it falls, 
 and which is only the condition of oscillation. 
 
 This view of the subject takes away many of the abstrac- 
 tions which have been connected with the action of the lever, 
 and with the motions of bodies in equilibrio. It throws over 
 all connected subjects a plain and intelligible law. The 
 mind escapes from embarrassment. What more simple idea 
 can we have in relation to the action of a lever of unequal 
 arms, where a smaller weight balances a larger weight and 
 oscillates with it, than to know that one in proportion to the 
 mass ascends in the degree in which the other descends, 
 the greater descent of the smaller weight affording sufficient 
 force for the less ascent of the larger weight, and the con- 
 verse ? How difficult to conceive that the earth, with an 
 attractive force in propotion to its mass, could draw down five 
 pounds so as to elevate ten pounds, merely because the two 
 unequal weights are at different distances from a certain 
 fixed point, though at the same distance from her centre ! 
 
 In a scale-beam balanced by two equal weights, how could 
 oscillation take place under the law of gravitation ? Yet 
 if you give one of these weights an impulse, they will oscil- 
 late, oscillate forever in a vacuum without friction. 
 Gravitation has no power to give alternate motion, at- 
 tracting both weights with equal force, it cannot first make 
 one heavier and then the other. If both were held with 
 
MECHANICAL PHILOSOPHY. 89 
 
 equal strength, it would be absolutely impossible for this 
 vibration to take place ; there is an absence of all cause, or 
 tendency, or capacity for oscillation. " Vis inertias of mo- 
 tion" gives no aid ; for the motion is suspended and renewed 
 at every vibration. Nor does " action and reaction;" for 
 the difficulty is to account for the action. The earth might 
 as reasonably be supposed to attract only one side of an 
 evenly balanced wheel, and thus give it continuous rotation, 
 as first to attract one weight and then another, when both 
 weights are equally heavy. The motion is unquestionably 
 from the transfer and retransfer of rotative force. The 
 balance rotates as one mass with one degree of force, but 
 this force flows from one part to the other of the mass. 
 
 So far from being able to induce oscillation, the law of 
 gravitation would immediately overcome the motion. The 
 power of attraction, it is said, mcreases with the decrease, 
 and decreases with the increase of the distance from the 
 centre of attraction. The weight going down is therefore 
 more forcibly attracted, the weight going up is more feebly 
 attracted, and this in an increasing ratio, both for the de- 
 pression and for the elevation. The difference, it may be 
 said, is so slight, that its results can never be detected by 
 observation. But slight as may be this want of equilibrium, 
 it actually exists. Balances have been made so perfect and 
 so nicely adjusted, as to turn by the impulse of the thou- 
 sandth part of a grain. Suppose a perfect balance without 
 friction at the fulcrum, and acting in a vacuum. Here 
 this want of equilibrium would be felt; the descending 
 weight, being more attracted, could not rise ; the ascending 
 weight, less attracted, could not fall. There could be no 
 oscillation under the law of gravitation. 
 
 Thus nature in the vast range of her adjustments would feel 
 
 8* 
 
90 OUTLINES OF A SYSTEM OP 
 
 and respond to this difference of attractive power at the 
 differing distances from the centre of attraction. Through- 
 out extended space there could be no oscillatory movement. 
 The spheres, according to theory, evenly balanced in their 
 orbits by the central and tangential forces, would, by mu- 
 tual attraction, have erratic movements. There would be 
 perturbations, actual perturbations, wanderings, actual 
 wanderings, from their path under the increasing power of 
 the lessening distance. Their changes could not be com- 
 pensatory and periodic ; the mean time of revolution and 
 mean extent of axis of orbit could not be preserved ; they 
 would aberrate, but never oscillate, for the force causing 
 aberration would be increased by the act of aberration. 
 
 On this earth too, under the law of gravitation, the order 
 of nature would be broken up. Off the Cape of Good 
 Hope, there are at times waves more than a half mile in 
 breadth, and very many miles in length. Millions and 
 millions of tons of water are thus heaped up in one volume ; 
 the increase and diminution of attraction in this case would 
 be felt and responded to, for there are out of balance thou- 
 sands of tons. It must be that the ascending water would 
 continue to rise, and the valley of depression to sink lower. 
 What too would be the result of the great tidal wave raising 
 and depressing the waters of an ocean ? Quietly to sink 
 the less attracted elevation, and abruptly to lift the more 
 strongly attracted depression ? Impossible ; under the law 
 of gravitation there can be no bound or limit, no oscillation 
 whatever. Perturbation, swerving motion, is without check. 
 There is no voice of command, Thus far and no farther 
 shalt thou rise, and here shall thy proud waves be stayed. 
 
 But on the other hand, in the hypothesis we offer, oscilla- 
 tion is measured in its extent by the impulse. The force of 
 
MECHANICAL PHILOSOPHY. 
 
 the undulation is neither an increasing nor a diminishing 
 force. It is not acquired from other bodies, nor imparted. 
 It exists in the mass moved, and is transferred from part to 
 part. It is a current of force flowing by an impulse. This 
 idea will be further elucidated as we proceed, and a prin- 
 ciple will be unfolded by which the oscillation of all fluids 
 is limited within a definite range, so that the equipoised and 
 freely moving element, water, has a fixed bound to its 
 oscillations. 
 
 We would rest the truth of the hypothesis on this nice 
 adjustment, this beautiful equipoise of motion by which is 
 secured the permanence and harmony of creation ; and 
 with these ideas, the rise of the wave reflects from its spray 
 not only the light of the sun, but its motion reflects to the 
 mind a more beautiful light, light revealing the law of 
 nature, by which movements as free as the breath of the 
 breeze are held in subjection with a chain so strong, that 
 He only who forged it can rend it asunder. 
 
 We will now recur more particularly to the phenomena 
 of the waves. To show that they are not distinctly under- 
 stood, we will cite the following description from a standard 
 work on Natural Philosophy: " Certain particles of water 
 are first forced down, and the surrounding particles are 
 forced up above their level ; their circular ridge subsides, 
 and not only fills up the original depression, but from its 
 momentum forces up another ridge exterior to it ; this sub- 
 siding forces up another ridge, and so on." This descrip- 
 tion calls to mind the following passage from an ancient 
 philosopher : " His whole performance seemed to reach no 
 further than if a man should say, ' Socrates does all by 
 intellect,' and after proposing to give a reason for my action 
 
92 OUTLINES OF A SYSTEM OF 
 
 should say, * I am sitting on my bed, because my body is 
 composed of bones and nerves ; the bones are hard, solid, 
 and separated by joints, and the nerves being able to bend 
 and unbend themselves tie the bones to the flesh, &c., and 
 that is the reason forsooth that I sit in this position.' ' 
 
 But we need an explanation of the phenomena of the 
 waves more distinct than comes from the mere recital of the 
 phases of their rise and fall. It is expressly mentioned by 
 Plutarch, and by Pliny, that the seamen of their day used 
 to still the waves by pouring oil into the sea. A letter writ- 
 ten in 1707, speaks of a storm at sea " which had nothing 
 particular about it, except that the captain found himself 
 obliged to pour oil in the sea, which had an excellent effect, 
 and succeeded in preserving us." Franklin, in his paper 
 on this subject, says : "A small quantity of oil, for in- 
 stance, a quarter of an ounce, will spread itself quickly on 
 the water in a pond to the extent of an acre, and if poured 
 on the windward side, the water will thereby be rendered 
 quite smooth as far as the film of oil extends Its prin- 
 cipal operation is to prevent the rising of new waves, and to 
 prevent the wind from driving those already raised with as 
 much force as it would if their surface was not oiled." 
 
 This idea of stilling the waves by means of oil is omitted 
 in recent works on the subject, and is considered by many 
 as a popular superstition ; but when was Franklin mistaken 
 in facts which he investigated ? and what popular belief is 
 there thus extensive which has no foundation in truth ? 
 Why is it, as before stated, that a thin stratum of oil spread 
 over the surface of water, will prevent its freezing when 
 exposed to a degree of cold much below the point of conge- 
 lation ? Why does oil prevent the adhesion of substances 
 pressed together ? All these results are from the non-con- 
 
MECHANICAL PHILOSOPHY. 93 
 
 ducting properties of oil. Force as heat does not escape 
 through it ; force of cohesion does not pass this barrier ; 
 force to give the impulse which occasions the undulation of 
 the waves, is repelled from the water. The theory of the 
 identity of force a priori, without experiment, would have 
 indicated these results. 
 
 A fact analogous to the rise of the wave, is the rise of the 
 air in a ventilating tube ; over the upper orifice passes 
 the horizontal wind, particles of which, by their friction 
 or attrition on the air in the tube, are arrested in their 
 course ; the force by which they were impelled is imparted 
 to the air in the ventilating tube, and consequently the air 
 is raised to a higher level of rotation. Wherever there is a 
 passage of a current of matter, any part of which is arrested 
 in its course, that which arrests it is moved. With this 
 idea fixed in the mind we are able, not only to give a satis- 
 factory explanation of the rise of the wave, but also of 
 many common facts coming under our daily observation. 
 
 When the wind passes over the surface of the sea, parti- 
 cles of this aerial current are arrested in their course by 
 any projecting inequality, or in the absence of already 
 formed waves, by friction or attrition, as already explained. 
 The water has additional force transferred to it by the 
 passing wind. It acquires force for rotation at a higher 
 level. It therefore rises. The elevation of the first wave, 
 however slight, offers a greater impinging surface ; it there- 
 fore continues to rise, and its rise is proportional to the 
 strength of the wind which causes it. This undulation of 
 the water arises from the same principle as the oscillation 
 of the pendulum, the motion of which is the reception and 
 transfer of the force of rotation at its different levels ; the 
 descent liberates force for the ascent, and one mean level 
 
94 OUTLINES OF A SYSTEM OF 
 
 of rotation is ever preserved. Thus rises the wave, its 
 motion the reception and transfer of force, its impulse of 
 oscillation the force robbed from the passing wind. Thus, 
 and thus only, can we explain a fact which is rather 
 indefinitely expressed in the following language from high 
 authority : " Momentum may be accumulated to an enor- 
 mous degree in very large suspended masses, by forces, 
 which, at their first application, appear to be totally inade- 
 quate to move them." The impulse ^s " totally inade- 
 quate " to cause the motion ; a child's hand cannot move 
 a thousand pounds, but the child's hand can destroy a 
 balance, and the force of nature transferred according to 
 the level of rotation is the cause of motion. In the case of 
 the wave, the wind destroys the equilibrium ; but the action 
 of a more intense force moves the mountain of waters. 
 
 The motion of the wave is deeply interesting in all its 
 aspects. The crests of the surge rise vertically, though 
 they are apparently progressive. It is not until the water 
 shoals toward the beach that they acquire a progressive 
 motion, progressive because near the shore there is not 
 depth for the vertical movement. It requires double the 
 generally supposed depth to form the vertical wave ; for 
 the uplifted water falls as much below the valley of depres- 
 sion as it rises above it. There is a descending wave, a 
 current under water, which as a wedge forces up the suc- 
 ceeding wave, an opposite wave under the water. Hence 
 on the shoaling water is the undertow, a retreat of the 
 water at a certain depth with advancing water at the sur- 
 face. The extent of this reciprocal wave is in exact pro- 
 portion to the extent of the visible wave. 
 
 Besides, the surface of the atmosphere is also to a degree 
 in oscillation with the water over which it is spread. The 
 
MECHANICAL PHILOSOPHY. 95 
 
 wind conforms to the surface, it oscillates with the water ; 
 the sails of a boat, or the lower sails of a ship, are not 
 becalmed with a steady wind, though surrounded by a wall 
 of water. Says an experienced navigator, " the lower sails 
 in scudding are at times becalmed, from the rise of the stern 
 of the ship, but never becalmed on the wind, though the 
 waves rise higher than the sails, a fact which I have often 
 tried to account for." For this reason, the undulating 
 motion of the wind over the undulating surface of the sea, 
 is it that the wind off shore, not having acquired the cor- 
 responding undulation, however strong it may blow, smooths 
 the sea. 
 
 A most interesting scene was described by a friend, who 
 stood on a small rocky island in the midst of the ocean, 
 looking with intense delight on the forces of nature as 
 displayed in a storm. The mountain waves were dark, 
 almost black, the intensity of their gloom being heightened 
 by the circle of white foam which surged upon the rocks. 
 A sudden veering of the wind, this wind being without 
 the conforming undulation, prostrated the billows as it were 
 at once ; the ocean became as smooth as in a summer's 
 breeze. There was no surge on the rock ; but the surface 
 of the sea was white with foam and curling in wreaths of 
 vapor as far as the eye could reach. Gradually, however, 
 the new wind acquired the sympathetic undulating move- 
 ment, the waves again began to rise, and soon the surf 
 dashed with its former fury against the island. 
 
 Only because the rise and fall of the wave are from the 
 reception and transfer of force, the mean level of the 
 ocean ever remaining the same, could this result have 
 been produced. If there had been " accumulation of mo- 
 mentum to an enormous degree," > if the attracting earth 
 
96 OUTLINES OF A SYSTEM OF 
 
 had drawn down the depressed waters with more strength 
 than the elevated waters, the ocean could never have 
 been thus smoothed into the quiet of one level ; the new 
 wind would have increased the surging waves, so that they 
 would have lifted their crests still higher in confused and 
 broken masses, resulting in a conflict of motion which the 
 strength of no vessel that ever floated could withstand. 
 There is something fascinating in the contemplation of the 
 intensity of the force of the elements so perfectly under the 
 control of law, as is witnessed on the barren rocks in the 
 midst of the ocean's storm. 
 
 Before passing to other instances of oscillatory move- 
 ment, we will notice some analogous phenomena. The whirl- 
 pool and the whirlwind are illustrative of the action of force. 
 We will copy first a description of these phenomena which 
 contains their usual explanation. " When gusts of wind 
 come from different quarters, and meet in a certain place, 
 there the air acquires a circular, or rotatory, or screw-like 
 motion, either ascending or descending, as it were, around 
 an axis ; and this axis is sometimes stationary, and at other 
 times moves in a particular direction. This phenomenon, 
 which is called a whirlwind, gives a whirling motion to dust, 
 sand, water, a part of a cloud, and sometimes to bodies of 
 great weight and bulk, carrying them upwards and down- 
 wards, and at last scattering them in every direction. The 
 water-spout is formed by the centrifugal force of the wind, 
 creating a vacuum in the centre through which the water 
 ascends." These are the common ideas ; for circular motion 
 is usually considered as the result of conflicting forces. 
 
 The action of two currents of water, in the formation of 
 the whirlpool, and of two winds in the formation of the 
 whirlwind, is precisely the same. The onward motion of the 
 
MECHANICAL PHILOSOPHY. 97 
 
 particles of water or air is arrested by the impingement of 
 the two currents, but the force which impelled them is not 
 annihilated ; the onward motion only is ended, and the 
 force from its nature must produce motion. The circular 
 is the only open range of action ; for no separate particle of 
 either stream can be accelerated in the stream by a sudden 
 impulse. Therefore, the arrested water or air moves in a 
 vortex until its force is gradually imparted to the current in 
 which it floats. 
 
 In the water-spout a part of the force of the revolving 
 wind is conveyed to the water ; the water, having force for 
 rotation at the higher level thus communicated to it, rises. 
 The water on which the whirlwind rests becomes violently 
 agitated with the additional force received, and is elevated 
 as foam, vapor, and water and air mingled together. Of one 
 an observer said, " the water at the base seemed to boil 
 and go up in detached masses mingled with the air." The 
 raising of heavy bodies on the land and of the water of the 
 sea by whirlwinds, in fact, the elevation of matter gen- 
 erally, is ever on the condition that the due degree of rota- 
 tive force is supplied. It may be supplied from below, as 
 in the act of pushing up ; it may be supplied from above in 
 the act of drawing up. All the phenomena of change of 
 level are explained on this principle ; the falling body 
 imparts its no longer needed force, the rising body demands 
 an increased supply. 
 
 This idea is finely illustrated in the fall of water from a 
 great height into a basin of stone, as in the "Pool" at the 
 White Mountains. The water received in the basin de- 
 scends from a great elevation ; it has great spare force of 
 rotation, which force, not transferred to the rock on which 
 it falls, impels the water in a vertical movement, and thus 
 
 9 
 
98 OUTLINES OF A SYSTEM OF 
 
 forms for itself a circular receptacle. If the water had 
 barely flowed into this receptacle without force, or from a 
 moderate elevation, the issuing water would have used this 
 force, a current between the inlet and outlet would have 
 been established, and no vertical movement been induced. 
 Water arrested between two currents makes the whirl- 
 pool. Arrested water from a great fall only, can make a 
 permanent whirlpool, which will scoop out for itself the 
 vortex mould from the solid rock. 
 
 A fact which has strayed somewhat from all theories, 
 and which the books on Hydrodynamics that we have 
 examined do not even notice, a trivial fact, coming under 
 our daily observation, is fully illustrative of the principle ; 
 we refer to the vortex in the body of a tunnel full of water, 
 which is formed on the issue of the water from the pipe 
 below. Fill a tunnel with water ; when it is stationary 
 allow it to flow out from the pipe ; the water in the tunnel 
 immediately assumes a vortical movement, and whirls faster 
 and faster as it descends. 
 
 We have inquired of many who were well read in the 
 usual explanations of philosophy, and their answer has been 
 that the cause of this vortex is the conflict of two forces. 
 How is this ? By theory, there is only one force present, 
 the force of gravitation, the downward drawing force of the 
 attraction of the earth. One suggested that the vortex was 
 formed by reason of the conical shape of the tunnel ; that 
 he was wrong is evident from the fact, that a tunnel of any 
 form gives the same result. 
 
 The explanation of the fact is very simple on the principle 
 which we present. The water issuing from the tube uses, 
 in its downward motion, all the spare force of its own 
 descent to a lower level. But the water remaining in the 
 
MECHANICAL PHILOSOPHY. 
 
 tunnel has also descended to a lower level of rotation. It 
 has therefore spare force, and this force has no other range 
 than to confer circular motion to the water. The water 
 therefore revolves. Thus is it, that facts, common, trivial 
 facts, declare the general law. 
 
 We return from this digression to oscillatory movements, 
 and affirm that the surface or crust of the globe, as it has 
 been called, has undulatory motion. 
 
 We think that we shall be able, as we proceed, to establish 
 the fact, that the barometer indicates, not the density of 
 the atmosphere and consequently the level of rotation, but 
 that it indicates this level positively and directly. For the 
 present, however, take the barometer as it is commonly 
 understood, as indicating by the oscillations of the mercury 
 the density of the atmosphere. 
 
 There are oscillations of the mercury entirely unac- 
 counted for by this theory. At the same apparent level 
 the barometer has a range of about three inches. This 
 well known fact cannot be explained by any supposed varia- 
 tion in the density of the incumbent atmosphere. Philosophy 
 acknowledges her ignorance of the cause of these changes. 
 The dryness or the humidity of the air will not account for 
 them ; this is admitted. Winds cannot give the reason ; 
 for it would require the passage of a current of air two 
 thousand eight hundred and eighty miles, at the rate of 
 sixty miles an hour, to account for a variation of one half 
 inch of the mercury. Besides, these changes often precede 
 the change in the atmosphere ; they may take place when 
 there is a dead calm, or during the blowing of a steady 
 gale, thus foretelling atmospheric changes rather than being 
 produced by them. Do not these facts indicate that the 
 same cause which changes the level of the barometer pro- 
 
100 OUTLINES OF A SYSTEM OF 
 
 duces the change in the atmosphere, not that the atmos- 
 pheric change affects the barometer ? 
 
 These oscillations of the mercury are not without cause, 
 and there is one cause to which we would assign them, 
 the rise and depression of the earth's surface on which the 
 barometer stands. We believe that the earth is to a degree 
 elastic, yielding ; that it is susceptible of undulatory move- 
 ment, periodic, or occasional, so extensive in range, yet 
 so slight in amount as to produce no convulsion, no apparent 
 change ; yet to be traced by the oscillations of the barom- 
 eter, and by the winds and storms which indicate a new 
 distribution of the force of rotation. 
 
 A scientific writer says, that the surface of the globe is no 
 more stable or firm comparatively than is a heap of saw- 
 dust which is floating on the surface of the water. This is 
 a strong metaphor, but he drew his inference from a suppo- 
 sition which we are far from believing, from hidden fires 
 shut up in the bosom of the earth. For, as he says, if in 
 the same proportion the heat continues into the interior of 
 the earth, which is evidenced by the fact of its increase so 
 far as we have penetrated, at one hundred miles from the 
 surface it would be greater than any artificial heat ever 
 produced. The most refractory substances would be reduced 
 to a fluid state ; therefore, the solid crust is of small com- 
 parative depth, and the internal fires by their intensity may 
 well be supposed to give motion to it. 
 
 But there are many well known facts which prove that 
 there are fluctuations of the surface of the globe. An ele- 
 vation of the coast of Chili of eighty-five feet has been proved 
 by geologists, and a recent elevation of four feet, extending 
 along a thousand miles of the South American coast, was 
 produced in a single night. Earthquakes have been felt 
 
MECHANICAL PHILOSOPHY. 101 
 
 throughout an entire hemisphere. During the great earth- 
 quake near Lisbon, the waters rose with the upheaving 
 earth one hundred feet, and the motion was propagated 
 across the Atlantic Ocean, vessels feeling the surge 
 according to their distance from the centre of motion. We 
 would also refer to the " periodic although irregularly alter- 
 nating rise and fall of the waters of the Caspian sea," and 
 to the fact that harbors in the Mediterranean sea have been 
 suddenly left dry for many hours. It is stated by an emi- 
 nent geologist, that the strata of the earth, her ridges, her 
 mountains and valleys take the general form that would be 
 induced by continuous undulations ; and geologists generally 
 assert the same fact, referring it to various causes. If there 
 be changes which result in convulsion, and which thus leave 
 a permanent record, why may there not be gentler changes, 
 fluctuations unattended with severe catastrophes or abiding 
 results ? We have the authority of Humboldt for the 
 assertion, that without earthquakes the surface of the earth 
 is capable- of gentle and progressive oscillations; and he 
 also remarks that " the opinion so implicitly entertained 
 regarding the force of gravity at any given point of the 
 earth's surface, has in some degree been controverted by the 
 gradual rise of large portions of the earth's surface." 
 
 The sudden changes of level in the waters of our great 
 lakes have long excited attention, and have never been sat- 
 isfactorily accounted for. We copy from the Annual of 
 Scientific Discovery a condensed account of the facts so 
 far as they are known, and the hypotheses which are offered 
 for their solution. " The results of recent observations prove 
 that these waters do not rise and fall at stated periods, cor- 
 responding to the ebb and flow of the tide, but are subject 
 to extraordinary risings, which are independent of the 
 9* 
 
102 OUTLINES OF A SYSTEM OF 
 
 influence of the -sun and moon. These risings attracted the 
 attention of the earliest voyageurs in these regions. Char- 
 levoix, who traversed the lakes nearly a century ago, says 
 in reference to Lake Ontario : ' I observed that in this 
 lake there is a sort of reflux and flux, almost instantaneous ; 
 the rocks near the banks being covered with water and un- 
 covered again several times in the space of a quarter of an 
 hour, even if the surface of the lake was very calm, with 
 scarce a breath of air. After reflecting for some time on 
 this appearance, I imagined it was owing to springs at the 
 bottom of the lake, and to the shock of their currents with 
 those of the rivers which fall into them from all sides, and 
 thus produce those intermitting motions.' The same move- 
 ments were noticed by Mackenzie, in 1787 ; by an expedi- 
 tion under Colonel Bradstreet, in 1764 ; on Lake Erie, in 
 1823 ; and at various later periods. In the summer of 
 1834, an extraordinary retrocession of the waters of Lake 
 Superior took place at the outlet of Sault Sainte Marie. 
 The river at this place is nearly a mile wide, and in the dis- 
 tance of a mile falls 18.5 feet. The phenomena occurred 
 about noon. The day was calm, but cloudy. The water 
 retired suddenly, leaving the bed of the river bare, except 
 for a distance of thirty rods, and it remained so nearly an 
 hour. Persons went out and caught fish in pools formed in 
 the depressions of the rocks. The return of the waters is 
 represented as having been very grand. They came down 
 like an immense surge. In the summer of 1847, on one 
 occasion the waters rose and fell at intervals of about fifteen 
 minutes, during an entire afternoon. The variation was 
 from ten to twenty inches, the day being calm and clear ; 
 but the barometer was falling. Before the. expiration of 
 forty-eight hours a violent gale set in. At Copper Harbor, 
 
MECHANICAL PHILOSOPHY. 103 
 
 the ebb and flow of the water through narrow inlets and 
 estuaries have been repeatedly noticed when there was not a 
 breath of wind on the lake. Similar phenomena occur on 
 several of the Swiss lakes. Professor Mather, who observed 
 the barometer at Copper Harbor during one of these fluctua- 
 tions, remarks : c As a general thing, fluctuations in the 
 barometer accompanied fluctuations in the level of the 
 water ; but sometimes the water-level varied rapidly in the 
 harbor, while no such variations occurred in the barometer 
 at the place of observation.' 
 
 " As a general rule, these variations in the water-level 
 indicate the approach of a storm, or a disturbed state of the 
 atmosphere. We are therefore led to infer that these phe- 
 nomena result, not from the prevalence of the winds acting 
 on the water, accumulating it at one point and depressing 
 it at others, but from sudden and local changes in the pres- 
 sure of the atmosphere giving rise to a series of barometric 
 waves." 
 
 How could there be these " sudden and local changes" 
 in the pressure of the atmosphere, with a calm day, and of 
 course an equable temperature ? Or how could they exist 
 at all in a fluid so elastic as the air, the very nature of 
 elasticity being such as to correct at once any difference of 
 density in the same volume ? Our views lead us to regard 
 these changes in the level of the water as indicative of 
 changes of the level of those portions of the earth on which 
 the water rests. And as a proof that vibration of the earth's 
 surface does occasion barometrical change, we need only 
 refer to the well-known fact that at the time of the great 
 Lisbon earthquake, the mercury fell so far in the barometer 
 even in Great Britain, " as to disappear from that portion 
 of the top usually left uncovered for examination." Hum- 
 
104 OUTLINES OF A SYSTEM OF 
 
 boldt also remarks that " the connection between the erup- 
 tion of a small volcano with the state of the barometer is 
 generally recognized, although our present knowledge of 
 volcanic phenomena, and the slight changes of atmospheric 
 pressure accompanying our winds, do not enable us to offer 
 any satisfactory explanation of the fact." 
 
 But we need not accumulate facts. Science generally 
 indicates a change of level of different portions of the crust 
 of this globe, taking place either periodically, or as it were 
 incidentally. Nor are we limited to science for our proofs 
 of mutation. Science may point to the barometer as indica- 
 tive of these changes ; she may show the earthquake and 
 the storm ; she may declare, from the upraised strata, from 
 the mountain ridges, from the depressed valleys, from the 
 confused commingling of the primitive, the transition, and 
 the recent formation, that the earth is not an unyielding 
 mass, bound together by a law which gives increased density 
 according to the approach to its centre. 
 
 The world, now permanent as the home of man, has 
 passed through at least one great and sudden change. The 
 upturned strata, the drift from the poles so enormous in 
 quantity, that were it again collected and restored it would 
 change the form of the earth, abundantly prove this. We 
 know that this great change has been accounted for by 
 natural causes, by the accumulation of the present changes 
 in foregone times, by the condensation, as it were, of 
 present events in the lapse of past ages, by the volcano, 
 the earthquake, the storm, the drift of rivers, the gradual 
 deposit of floods ; glaciers have been launched, and ice- 
 bergs freighted with diluvium and boulders. We are not pre- 
 pared to seek a solution of the great changes of the earth 
 from natural causes, from the intensification of the present 
 
MECHANICAL PHILOSOPHY. 105 
 
 action of force, condensed to stronger action in the youth of 
 the world. There has been one change at least, which came 
 not from a natural cause, from the e very-day phenomena of 
 nature. We refer to the time when the earth was without 
 form and void, and darkness was on the face of the deep, 
 when the spirit of God moved on the face of the water, 
 and it was said, Let there be light, and the rays of the sun 
 created " in the beginning" for the first time penetrated the 
 mist that went up from the surface of the earth ; when " the 
 firmaments rose " and " divided the waters from the waters." 
 
 How great the change which thus converted a chaotic 
 world into a bright and beautiful home for man ! The 
 intensity of the force is written down on the broken strata, 
 the torn and ragged mountain ridges, and in the smoothing 
 and furrowing of the stubborn rocks. The form of the 
 earth was changed, and with this change came necessarily 
 a change of its rotation, and it may be of the form of its 
 orbit ; for a change in one condition of a sphere, must 
 change its every phase. 
 
 And that this change did take place proves that there 
 can be no reference to any supposed centre as the radiating 
 point of its motive force ; for the globe is self-poised, asking 
 of no other leave to be, borrowing of no other the power to 
 move, connected, as a part of a system of worlds, yet 
 speeding on in a path of her own in perfect balance, in ac- 
 curate equilibrium, as if buoyed up by the right arm of God. 
 
 As there is a perfect equipoise in the earth as a sphere, 
 as a whole, so is there the same perfect equipoise in her 
 parts, in her elements, in her constituting masses. From 
 this perfect equipoise come the slight aberrations and per- 
 turbations, the oscillations of the surface. As the pendulum 
 swings on the condition of equilibrium ever preserving one 
 
106 OUTLINES OF A SYSTEM OF 
 
 mean level, so may the surface vibrate of the even-balanced 
 earth. Therefore is there freedom, ease, elasticity of mo- 
 tion, nothing stationary, yet nothing wandering to an 
 extent that can mar the designs of creative wisdom ; all 
 things flowing gently as if without rule, yet bound together 
 by laws as sure and as unchangeable as is the power of Him 
 who formed the earth in the beginning, as the home of his 
 children, whose security and happiness were the objects of 
 creative skill. 
 
 An idea given in a sermon by the Rev. A. P. Peabody 
 has fastened itself in our thoughts ; we quote from memory : 
 " In the Ptolemaic system, this earth was considered as the 
 centre of the system to which all the wandering hosts of 
 heaven were tributary, aids, accompanying circumstances. 
 The better lights of astronomy dispelled this error, and the 
 earth is looked upon now as a part, a minute part of a uni- 
 verse without a conceivable limit. But the earth from this 
 is not degraded, but exalted, not decreased, but increased 
 in interest. The part of such a whole far transcends in 
 sublimity the centre of a system so narrow that all refers to 
 its own limited bounds." The idea extended to man imparts 
 to the individual a dignity proportional to the extent of the 
 universe of which he is a participant, -- little in himself, yet 
 how great considered as an intregral part of the whole crea- 
 tion ! And this intimate connection, too, not merely apper* 
 tains to his physical nature, but he has yet greater dignity 
 of position from the view that, connected as he is with God's 
 material universe, there is also for him a connection with the 
 Sustaining Spirit, the Life of the Universe, that indeed 
 he is the child of God, 
 
 We return from this " oscillation " of thought, In a 
 
MECHANICAL PHILOSOPHY. 10T 
 
 still night, at a hotel of great extent, built of massive 
 granite, a vibratory motion was distinctly perceptible. 
 This great stone building, the adjacent buildings of brick, 
 and the intervening ground to a great extent were perceptibly 
 moved by the passing of a carriage over the paved street. 
 Did the muscular force of the horse thus produce motion of 
 the enormous mass of stone, brick, earth, and the solid 
 ledge ? The impulse only was given, and this impulse, 
 slight as it was, so nicely adjusted is the balance of force, 
 resulted in oscillation. The vibration called forth by the 
 motion of the carriage, was the bringing into action the 
 weight of the mass, the transfer and retransfer of the 
 force of rotation as the oscillating matter rose and sunk in 
 level. Had gravitation bound down the enormous mass, 
 drawn it with the force of thousands of thousands tons, it 
 would have stood firm and unyielding. How much safer 
 for a ship to float on the free moving water, than to re- 
 ceive the shock of the storm when stranded on the solid 
 rock ! 
 
 As we write, we raise our eyes to a range of lofty moun- 
 tains, the top of one of which rises some four thousand feet, 
 with a summit of bald rock, the granite reaching from this 
 height to the broad base, and extending for many long miles 
 below, ledge upon ledge, stratum upon stratum, all bound 
 together by the circulation of force through every particle, 
 fragment, mass. But there is no weight. The granite 
 crystals touch each other no more closely at the lowest base 
 than at the summit, nor press more heavily on each other. 
 There is no weight, except on the condition that the mountain 
 descends to a level of rotation. It is self-poised, as is the 
 whole earth. 
 
 Practical men, who know only what they have seen, and 
 
108 OUTLINES OP A SYSTEM OF 
 
 believe in what takes place, without being troubled by 
 theory, work on the faith that there is no force of gravita- 
 tion in the mass which preserves one line of rotation. In 
 taking away 'the foundation of a brick wall which had been 
 undermined, to rebuild it, the owner expressed his fears 
 that too much had been removed of the support at 
 once, and that the building would fall. The reply of the 
 mechanic was, " I used to fear, but now I know that it is 
 safe until it begins to move, and I shall work without any 
 jar ; if it should begin to move, twice the present support 
 would not keep it up." In taking away the support of the 
 arch of a stone bridge, after the keystone was put in, a 
 slight, sudden sag of the bridge crushed the keystone, a 
 stone, the cohesion of which, if standing firm at one level, 
 would have borne all the granite that could have been piled 
 miles high upon it. 
 
 This principle is evidenced by the superior security of the 
 arch for bridges and similar structures. In the arch, there 
 can be no descent without crushing the material of which it 
 is formed. Thus too has the passing of a body of troops 
 over a bridge, with measured step by beat of drum, often 
 given the vibration which calls into action the weight or force 
 of descent. In the Britannia tubular iron bridge of immense 
 weight, some of the spans of which are four hundred and 
 seventy-two feet in length, care has been taken to secure 
 the bridge against vibration ; the upper portions of the tube 
 are made thicker, operating as an arch, the particles of 
 which are compressed by any descent. Heavy as it is, it 
 will undoubtedly stand if it has no vibration to call forth the 
 force of descent. 
 
 The moon floating around the earth will not fall because 
 she possesses force for rotation, in proportion to her distance 
 
MECHANICAL PHILOSOPHY. 109 
 
 from the earth. So the crust of the earth cannot fall, as it 
 ever has the due force for rotation ; there may be oscilla- 
 tion in the orbit of the moon, the mean distance being pre- 
 served ; there may be a movement of the earth's surface, but 
 it is an oscillatory movement ; there is both the rise and the 
 fall, one mean of rotation being preserved. Masses and frag- 
 ments of the earth fall, when unsupported they take a lower 
 level of rotation, and as they fall yield up to other bodies 
 the force of their former superior level. Hence every 
 movement is oscillatory, the transfer of force, the force 
 remaining of fixed quantity in all its transfers, preserving 
 the perfect equilibrium of creation. 
 
 After the assertion of the law of falling bodies by Galileo, 
 there was found a great difficulty in applying it to the 
 commencement of the motion ; for this beginning of motion 
 clearly shows that they do not fall by attraction. Great 
 disputes took place in regard to the velocity with which 
 bodies begin to fall. It led to the consideration of the infinite 
 divisibility of space ; for the motion at its commencement is 
 so slight that the body hardly appears to move, or, as it has 
 been expressed, " when a body begins to fall from rest, it 
 begins to fall with no velocity. In one thousandth part of 
 a second it has only acquired one thousandth part of the 
 velocity which it has at the end of one second." If gravi- 
 tation act with its supposed force upon a body at rest, how 
 great would be its instantaneous velocity when the support 
 was taken away ! Its fall would be as sudden as the recoil 
 of a bent spring. 
 
 Nor could it be understood why bodies which had fallen 
 by the force of gravity should be able to rise again to the 
 same level against the force 'of gravity ; or why on the 
 inclined plane the velocity of a body should be measured by 
 
 10 
 
110 OUTLINES OF A SYSTEM OP 
 
 the vertical height from which it falls ; nor why the fall 
 should be with uniformly accelerated velocity. Even Gal- 
 ileo, vigorous as were his powers of thought, could not mas- 
 ter the subject. And the obscurity has continued to this 
 day. 
 
 The theory of gravitation acknowledges a difference be- 
 tween the weight of a body, that is, its tendency to fall, 
 and the force of the fall, weight being an invariable quality, 
 while the force of descent is in proportion to the time of the 
 fall. We rega'rd the cause of the fall, and the force given out 
 by the fall as essentially different, and we hope that we shall 
 be able, in the process of this inquiry, to explain the cause 
 as well as the results. But whatever it may be, the stone 
 unsupported will not remain at rest. We have just read in 
 an account of a recent ascent of Mont Blanc, that " spots 
 have to be passed where no word can be spoken lest thou- 
 sands of tons of snow should be set in motion ; " for it has 
 been known, that the mere vibration of the air, caused by 
 the human voice, has brought down the avalanche. The 
 intensity of molecular action, the pulse of nature, the very 
 throb of force, the vibration and oscillation of all things 
 would account for the fact that the suspended body has 
 motion, has the beginning of its downward course. The 
 impulse given, the most minute line of descent induced, 
 there is the spare force of rotation, there is force for the 
 motion of the mass in a new direction. It has commenced 
 its fall, it has unused force. It cannot rotate more rapidly 
 at the lower level ; for it is a part of a current of matter 
 passing round the earth in an equable stream. * Downward, 
 then, it must take its way. Its very appearance in the 
 act of falling indicates the law of its motion. It is not at- 
 tracted ; for it does not rush at once to the earth, as do the 
 
MECHANICAL PHILOSOPHY. Ill 
 
 particles of steel to the magnet ; but, for an instant, as if in 
 suspense, like 
 
 " A long-swept wave about to break, 
 It on the curl hangs pausing ; " 
 
 then, gathering force for its downward career, it falls ; 
 
 " Still gathering force it smokes, and urged amain, 
 Whirls, leaps, and thunders down, impetuous to the plain." 
 
 The force obtained by the change of the level of the falling 
 mass, of water for instance, cannot come from the at- 
 tracting earth ; for the attractive force is force to draw the 
 mass toward her centre, and having acted according to this, 
 the essential principle of attraction, it would cease to act, or 
 merely hold the water at its new level. But the force of 
 the fall of bodies remains ; it is a living principle. It was 
 in them at their higher level, there acting in rotation. If 
 water falls, it transfers this force to other bodies, inducing 
 motion in them. If not imparted, it is sufficient in intensity 
 to raise the water again to its former level. It is not a 
 mere gravitating, or downward force, but force giving motion 
 irrespective of direction. 
 
 Thus, the fall of water over an artificial dam is not from 
 the downward attraction of the earth. That force can only 
 exert its essential property of bringing the particles of mat- 
 ter nearer to each other. In doing this, it has discharged 
 its only conceivable function. But the particles of water 
 by the act of descent impart the spare force of their lower 
 level of rotation; and this force, diverted from the majestic 
 stream of rotative power, can have given to it by mechanical 
 appliances the line of direction which crushes the grain, or 
 on the revolving spindle twirls the fibre of cotton, the 
 mechanic using the force of nature for the comforts and 
 
112 
 
 luxuries of life. Thus is imparted to the practical mechanic 
 a dignity arising from his position. He is not a mere cun- 
 ning workman in wood and brass ; but he bears in his hand 
 the sceptre of power over nature, he controls her ener- 
 gies, he borrows her force, from water, wind, and steam, 
 and through the lever and the wheel, he directs the action of 
 this force for the well-being of man. 
 
 When engaged in the examination of facts, the thoughts 
 will oscillate from them to abstract principles, from 
 material things to that which they represent. Does not 
 this law of the mind prove that the connection of the intel- 
 lect with material objects is not its only tie to the universe ? 
 We have considered the artisan as borrowing the power 
 of nature for his purposes, considered him as not confined 
 to that degree of strength only which flows through his own 
 frame ; he goes out of himself to the great fountains of 
 energy for his purposes. So, he who would comprehend the 
 things around him, he who is the artisan in philosophy, 
 is he confined to his own feeble strength, limited to his own 
 power of thought ? Is there not a communion between him 
 and truth more direct than comes from the contemplation of 
 external objects merely ? Is he never allowed to borrow 
 wisdom from the Fountain of Wisdom ? 
 
 " Now all the knowledge and wisdom that is in creatures, 
 whether angels or men, is nothing else but a participation 
 of that one eternal, immutable, and uncreated wisdom of 
 God, or several signatures of that one archetypal seal, or 
 like so many multiplied reflections of one and the same face, 
 made in several glasses, whereof some are clearer, some 
 obscurer, some standing nearer, some further off." 
 
CHAPTER VI. 
 
 " SURELY IT IS A WORK WELL DESERVING OUR PAINS, TO MAKE A STRICT 
 INQUIRY CONCERNING THE FIRST PRINCIPLES OF HUMAN KNOWLEDGE, 
 TO SIFT AND EXAMINE THEM ON ALL SIDES ; ESPECIALLY SINCE THERE 
 MAY BE SOME GROUNDS TO SUSPECT, THAT THESE LETS AND DIFFI- 
 CULTIES, WHICH STAY AND EMBARRASS THE MIND IN ITS SEARCH 
 AFTER TRUTH, DO NOT SPRING FROM ANY DARKNESS AND INTRICACY 
 IN THE OBJECTS, OR NATURAL DEFECT IN THE UNDERSTANDING, SO 
 MUCH AS FROM FALSE PRINCIPLES WHICH HAVE BEEN INSISTED ON, 
 AND MIGHT HAVE BEEN AVOIDED. 
 
 " HOW DIFFICULT AND DISCOURAGING SOEVER THIS STEP MAY SEEM, 
 WHEN I CONSIDER HOW MANY GREAT AND EXTRAORDINARY MEN HAVE 
 GONE BEFORE ME IN THE SAME DESIGN, YET I AM NOT WITHOUT SOME 
 HOPES, UPON THE CONSIDERATION THAT THE LARGEST VIEWS ARE NOT 
 ALWAYS THE CLEAREST, AND THAT HE WHO IS SHORT-SIGHTED WILL 
 BE OBLIGED TO DRAW THE OBJECT NEARER, AND MAY PERHAPS, BY A 
 CLOSE AND NARROW SURVEY, DISCERN THAT WHICH HAD ESCAPED 
 
 FAR BETTER EYES." Bishop Berkeley. 
 
 THERE are, unquestionably, two different casts of mind, 
 one giving greater, the other less attention to facts ; the 
 one the more rigid and exact in observation, the other 
 the more prone to speculation. Hence the perpetual con- 
 flict between what are called the practical and the theoret- 
 ical. But the dispute concerning the values of the two 
 methods in philosophy is in words merely. The man who 
 only knows facts, and the man who, ignorant of the doings 
 of nature, dreams rather than judges, are both unfit for 
 philosophy. Theories unsupported by facts are worthless, 
 and an accumulation of facts without reference to the laws 
 of their combination is also worthless. 
 10* 
 
114 OUTLINES OF A SYSTEM OF 
 
 But every man is in some degree a theorist, and he 
 is a theorist because he is a man. The animal alone 
 rests contented with the facts presented to the senses. In 
 proportion to the strength of a mind is its tendency to 
 go beneath the surface of things, to be dissatisfied with- 
 out hypothesis to connect the facts that are observed, 
 and therefore to seek some principle of unity. Thus every 
 philosopher is necessarily a theorist. Even Bacon, the 
 father of the Inductive Method, was a theorist, and at times 
 a wild and fanciful theorist. " Some noises," says he, 
 " help sleep, as the blowing of the wind and the trickling of 
 the water ; they move a gentle attention, and whatever 
 moveth attention without too much labor, stilleth the natural 
 and discursive motion of the spirits." " What indeed," 
 asks a profound and accurate thinker, " are Newton's Que- 
 ries but so many hypotheses which are proposed to philoso- 
 phers as subjects of examination ? " " And," he continues, 
 " did not even the great doctrine of gravitation take its first 
 rise from a fortunate conjecture ? " 
 
 It is remarked by Sir David Brewster that " the influ- 
 ence of the imagination as an instrument of research has 
 been much overlooked by those who have ventured to give 
 laws to philosophy. This faculty is of the greatest value in 
 physical inquiries ; if we use it as a guide and confide in its 
 indications, it will infallibly deceive us ; but if we employ it 
 as an auxiliary, it will afford us the most invaluable aid." 
 After an hypothesis has been suggested by the imagination, 
 it should become the subject of rigorous examination, and be 
 retained or discharged, as it may or may not give the desired 
 explanation ; for the proof of the truth of a theory is its har- 
 mony with facts. True philosophy, therefore, uses both 
 reason and observation in making progress. 
 
MECHANICAL PHILOSOPHY. 115 
 
 And while philosophy demands that no theory shall be 
 admitted as proved any further than it is supported by facts, 
 and that science should be guarded from wayward fancies 
 and day-dreams, equal care should be taken to reexamine 
 the theories that are current, so that the errors that must 
 necessarily be handed down in the regular transmission of 
 science, from the education of one generation by the pre- 
 ceding, may be expelled. There is far less danger that 
 new errors be received than that old ones be suffered to re- 
 main ; for against new theories the educated contend most 
 strenuously, if they conflict with a system to the full com- 
 prehension of which a lifetime has been devoted. Errors 
 once established therefore become permanent ; they are 
 incorporated into a system. Common sense, which might 
 detect them, defers to the authority of science, and science 
 to the wisdom of former times. However, all things on the 
 whole are wisely determined so that progress shall be made, 
 though it be by a succession of waves surging at long inter- 
 vals, rather than by the steady advance of the tide. But 
 we have been drawn from our path. We return to the exam- 
 ination of the theories relating to the differing densities of 
 the atmosphere, as indicated by the rise and fall of the 
 mercury in the barometer. 
 
 It is generally supposed that the atmosphere increases in 
 density from its upper surface to its line of contact with the 
 globe. In the language of Sir John Herschell, " when we 
 have ascended to the height of one thousand feet, we have 
 have left below us about one-thirtieth of the atmosphere ; at 
 ten thousand six hundred feet of elevation, rather less than 
 that of JEtna, we have ascended through about one third ; 
 at eighteen thousand feet, which is nearly that of Cotopaxi, 
 through one half of the material, or at least of the pondera- 
 
116 OUTLINES OF A SYSTEM OF 
 
 ble body of air incumbent on the earth's surface." This 
 lessening density as we go up from the surface, is supposed 
 to be proved by the depression of the mercury in the 
 barometrical tube. 
 
 Before the experiments of Torricelli, the ascent and sup- 
 port of fluids by a vacuum were accounted for by the abhor- 
 rence of nature for a vacuum. When it was discovered 
 that this "abhorrence" was limited for water to about 
 thirty-three feet, for mercury to about thirty inches, and 
 for other fluids in proportion to their density, some new 
 theory became necessary, and the weight or pressure of the 
 atmosphere was substituted. Galileo, Torricelli, Pascal, 
 seem jointly to have formed the new theory, and Pascal 
 fully established it by experiments, which gave the fact that 
 at different altitudes the level of the mercury varied, that 
 it rose higher in the vacuum as the level of the instrument 
 decreased, and that it fell as the barometer was elevated. 
 
 Thus the "fuga vacui" being abandoned, the support of 
 the fluid being attributed to the pressure of the atmosphere, 
 and the degree of support being found to lessen upon ascent, 
 the hypothesis that the weight or pressure of the atmosphere 
 decreases according to elevation was established, and re- 
 mains unquestioned to this day. This theory, however, 
 though it has been useful for many practical purposes, does 
 not give a complete explanation of the facts connected with 
 the barometer. 
 
 How is the air supposed to be packed according to baro- 
 metrical indications ? We will quote from one who very 
 distinctly gives the commonly received opinions. " The 
 first stratum of air gravitates with its own share of the 
 earth's attraction, the second with its own share, and with 
 the weight of the stratum over it, and so on ; the lower 
 
MECHANICAL PHILOSOPHY. 117 
 
 stratum bearing in addition to its own weight all the weight 
 of the air over it." The atmosphere has also been com- 
 pared to a series of fleeces of wool, the lower the most 
 compressed. 
 
 Gravitation of the atmosphere, if the air be attracted at 
 all, would appear at first sight as if threads were attached 
 to each particle, drawing every one with equal tension. No 
 particle could rise relatively to another particle, if all were 
 drawn down with equal force. The particle going down 
 must be more strongly drawn, the particle going up must 
 be drawn with less comparative force. With equal attract- 
 ion there could be no relative change of place. The only 
 difference in weight of the different strata would arise from 
 the increase or diminution of the force of attraction, accord- 
 ing to the distance of each stratum from the centre of 
 attraction. If this force acted on the whole atmosphere as 
 one volume, the whole volume would be of as uniform den- 
 sity as a mass of granite. If the force of attraction operated 
 on each particle according to its distance from the centre of 
 attraction, the difference in the weight qf different strata 
 would be far less, than that apparently indicated by the 
 barometer. 
 
 Such a condensation of the atmosphere as is supposed 
 could not result from the law of gravitation ; for that law 
 assumes a decrease of force proportional to the square of 
 the distance. A volume of one hundred cubic inches of air 
 weighs but thirty-one grains, is attracted by a force the 
 value of which is only thirty-one grains. How large must 
 be the volume of air which weighs a ton, is attracted by a 
 force measured by one ton ? It would cover the whole of a 
 large and high mountain. This ton of air would weigh but 
 one ounce less, a mile from the surface of the globe, than it 
 
118 OUTLINES OF A SYSTEM OF 
 
 would at its very surface. This is the only ratio in which 
 gravitation could change the weight of the different strata 
 of air. The earth can have no favoritism. She holds in 
 place or draws down every particle of air equally, or, 
 more accurately, in proportion to its distance from the 
 centre. 
 
 But, admitting that each stratum of air bears not only its 
 own share of the earth's attraction, but also the weight of 
 all the strata over it, still this could not condense the atmo- 
 sphere to the degree that is supposed. 
 
 No one doubts that the temperature of the atmosphere 
 changes with its level. At the summit of a mountain, where 
 by theory the air has lost one half of its density, the cold 
 compared with that at the surface of the earth below is 
 most intense. Heat, it is said, always rarefies the air, cold 
 condenses it ; and of course there would, from this cause, 
 be a greater density in proportion to the elevation. 
 
 It is also settled, that the force of the elasticity of air 
 increases with its density. Of course elasticity acts against 
 the rarer strata, and this elasticity would of itself pre- 
 serve throughout the whole atmosphere an equilibrium of 
 density. If a quantity of air be artificially condensed, how 
 quickly will it return to its normal state when the force 
 which compresses it is removed ! If the air be an elastic 
 fluid, no volume of it can exist without an equal pressure in 
 every direction, be the volume large or small, a few cubic 
 inches or the whole atmosphere. If any portion of it be 
 rarefied by heat, this will give to its particles greater < c force 
 of repulsion," so as to equalize its pressure with that of the 
 surrounding denser air. 
 
 Moreover, if gravitation could press down the different 
 strata of the air in the ratio supposed, it could not maintain 
 
MECHANICAL PHILOSOPHY. 119 
 
 the pressure, it could not preserve this difference of den- 
 sity. There is a perfect intermobility of the particles of 
 fluids, and every wind that blows would tend to bring back 
 the equilibrium. It is supposed that winds are caused by the 
 rushing of air from the colder and more condensed portions 
 of the atmosphere to those comparatively more rarefied. 
 An upward current would at once be established to restore 
 an equilibrium, to undo what gravitation had done. 
 
 But the law by which the atmosphere is packed ac- 
 cording to barometrical indications, is not the law which 
 regulates the gravitation of fluids. It is a law which acts 
 in this case only. The law, by which one stratum of the 
 atmosphere bears not only its own weight, but that of all the 
 strata over it, is assumed for special purposes. Having dis- 
 charged its function, it is, ever after, a dead letter. We 
 hear no more of this vertical gravitation, no more of the 
 bearing down of one stratum upon another. Fluids press 
 equally in all directions. This is acknowledged as a general 
 law. The very action of the atmosphere on the barometer 
 must ofcen be by an upward gravitating power, pressing 
 against the leather at the bottom of the cistern containing 
 the mercury. 
 
 The acknowledged principle that the pressure of fluids is 
 equal in all directions, " upwards, downwards, and side- 
 ways," would prevent such a compression of the atmosphere 
 as the barometer is supposed to indicate. If a cubic foot of 
 air presses equally by its six sides, it presses the cubic foot 
 above it with the same force as the cubic foot below it. In 
 no way whatever can it be shown, without contradicting all 
 the present theories, that there is a difference of density 
 among the different strata of air. If this difference actually 
 exists, we must give up gravitation with force according to dis- 
 
120 OUTLINES OF A SYSTEM OF 
 
 tance, the action of heat in the rarefaction of the air, the 
 elasticity of air in proportion to its density , the diffusiveness 
 of air, the intermobility of the particles of air, and the prin- 
 ciple that the pressure of fluids is equal in every direction. 
 
 But in fact the varying density of the air has no proof 
 whatever. It may be, or may not be. If it be, it is caused 
 by a principle not embraced in any of the present theories, 
 and it cannot be proved from the range of the mercurial 
 column. We wish to express this idea distinctly. If the 
 air be more dense at the surface of the earth than a 
 mile above it, the increase of density does not arise from 
 gravitation ; and, if there is a difference of density at differ- 
 ent levels, the barometer cannot indicate it. 
 
 We referred, in the preceding chapter, to the oscillations 
 of the mercury at one supposed level ; we have occasion to 
 use again the same facts, and to add to them others of the 
 same character. 
 
 These oscillations, of which the range is about three 
 inches, while the barometer remains at the same place on 
 the earth's surface, are not accounted for by the present 
 philosophy. Scientific men confess their inability to explain 
 them. Professor Daniell says, " The cause of these oscilla- 
 tions has long been the subject of investigation with philos- 
 ophers, and the problem in all its generalities is difficult and 
 complicated." " The difficulty," says an article in the 
 London Encyclopedia, " consists in explaining why these 
 oscillations are greater in high latitudes than between the 
 tropics, as well as why they should exceed in all cases the 
 quantities which calculation of different densities of atmo- 
 sphere might assign." Again : " It is hard to say what can 
 be the cause of the changes of the height of the mercury at 
 the same level, changes which would be equal to a change 
 of level of two or three thousand feet." 
 
MECHANICAL PHILOSOPHY. 121 
 
 Ifc is supposed by some that different degrees of hu- 
 midity in the atmosphere might account for these changes. 
 Professor Leslie inclines to this belief, " because all other 
 assigned causes are insufficient." But the barometer usually 
 falls in a damp atmosphere, and vapor of itself has weight, 
 nor does it necessarily rarefy air which contains it. The 
 winds passing over the surface of the earth cannot be the 
 cause ; for, as we have already shown, it would require a wind 
 passing over nearly three thousand miles at the rate of sixty 
 miles an hour, to change the height of the mercury half an 
 inch. Attempts have also been made to trace the cause in 
 the vacua occasioned by conflicting winds. In vain ; for 
 winds by theory restore equilibrium, they do not create 
 inequalities, nor could a vacuum exist for days and weeks 
 if it could be formed. 
 
 The maximum of oscillation is near the parallel of 45 
 latitude. The oscillations vary with the time of the year, 
 (being greater in one month, less in another month,) and also 
 with the hour of the day. They also vary with sudden 
 changes of the level of the water, with the height of the 
 tides, and with the position of the moon in relation to the 
 earth. All these periodic and other changes cannot be 
 traced to the state of the atmosphere as the cause. There- 
 fore, if the barometer indicates varying density of the atmos- 
 phere, it also indicates some other fact, the oscillations 
 have some other cause. If it do not indicate the density of 
 the air in one position on the earth, it may not in any, espe- 
 cially as the corresponding variation of density has no proof 
 independent of the change in the mercurial column. 
 
 But it may be thought that we have forgotten the fact that, 
 " if a man ascends a high mountain, he will feel an incon- 
 venience in his ears, and other cavities of the body from the 
 11 
 
122 OUTLINES A SYSTEM OP 
 
 dilatation of the enclosed air adjusting itself to the dimin- 
 ished outside pressure." This /act, if it be true, is insuffi- 
 cient to bear the burden of proof of the great principle under 
 discussion. If uncomfortable bodily sensations are experi- 
 enced, it does not follow that the reason for them is the 
 " dilatation of the inclosed air," or the rarefaction of that 
 outside. There may be other reasons for painful sensations 
 on the ascent of high mountains. 
 
 The effect on the animal structure of the air at great 
 heights, we think, proves distinctly that it is not so rarefied 
 as is supposed. The bird soars as lightly from the top of 
 the high mountain as from the plain. The condor, the 
 heaviest of birds, flies without effort at a height of fifteen 
 thousand feet, though supported by air of only half the 
 density of that below. And man, after recovering from the 
 fatigue of ascent, is not always distressed for breath ; he 
 does not require lungs of double capacity, nor does he 
 breathe twice as fast to obtain his usual supply of vital air. 
 No one could live comfortably in air of only half its usual 
 density ; yet in the highest ascents in balloons we read 
 that " the aeronauts suffered no inconvenience in their respir- 
 ation or other animal functions." We shall again recur to 
 this part of the subject. 
 
 It may also be alleged that the boiling point of water 
 varies according to elevation, because the pressure upon the 
 surface of the water is diminished by the rarefaction of the 
 air ; or that, as water boils in vacuo at a very low tempera- 
 ture, so as we ascend and the air is rarefied, water boils with 
 a less degree of heat. The reason why water boils more 
 easily the greater its elevation, is simply its possession of a 
 rotative force proportional to its level of rotation. Beyond 
 a certain elevation water would at once pass into vapor. 
 
MECHANICAL PHILOSOPHY. 
 
 We do not expect the minds of others, at this period of 
 the investigation, to accept pur explanation of the vaporiza- 
 tion of water at different levels. We will, therefore, for 
 the present, admit that the atmosphere is more or less rare- 
 fied according to the altitude of its strata, that the mean 
 weight of the air, from the action of heat or other causes, 
 varies, so as to make a column of it bear on the earth some- 
 times with a greater, sometimes with a lesser pressure. 
 But even if we admit the gravitation of air, and the varying 
 weight of a given quantity of air, it does not follow that 
 either its normal pressure or its variation of pressure is 
 measured by the stationary or varying weight of the sus- 
 pended column of mercury. In other words, there is no 
 proof that the weight of the column of mercury is the 
 measure of the weight of the air. 
 
 In the first place, when the barometer is constructed, the 
 mercury in the tube does not owe its elevation to the press- 
 ure of the air. Let a tube closed at the top be immersed 
 in mercury, and when filled let it be withdrawn upward by 
 the hand ; the mercury is raised with the tube above the 
 level of the mercury from which it is taken. The force re- 
 quired to lift it is just the weight of the mercury and tube 
 together. The pressure of the atmosphere on the lower 
 surface of mercury does not in tae least degree aid in the 
 elevation, does not diminish the weight, because the sus- 
 taining mercury is pressed by the air, not one iota less of 
 force is required to give the sustained mercury its eleva- 
 tion. The fact is admitted, and is accounted for in this 
 manner : " The force used in lifting the mercury is 
 needed to elevate the air over the tube ; that being done by 
 the applied force, it is the weight of the atmosphere which 
 elevates the mercury in the tube." But this reason is 
 
124 OUTLINES OF A SYSTEM OF 
 
 given without reflection ; for the air is no heavier over the 
 tube when the tube is filled with mercury than when it is 
 filled with water or air, yet the force applied measures the 
 weight of the fluid within, and the contained weight does 
 not increase or diminish the weight of the column of air 
 over the tube. It is certain, therefore, that when the 
 column of mercury is lifted with the tube, it is the applied 
 force that lifts it, and not the weight of the atmosphere 
 bearing on the surface of the mercury from which it is 
 withdrawn. Of course, the weight of the atmosphere, not 
 capable in the least of aiding the process of elevation, has 
 no efficacy in sustaining the column w r hen raised. One 
 would almost suppose that an air-supported column of mer- 
 cury would be like the air-supported balloon, and would not 
 press with any weight upon the instrument. 
 
 When the tube is elevated beyond what may be termed 
 the limit of extension, the mercury is no longer lifted with 
 it. However high the tube be drawn, the surface of the 
 mercury in it remains at a certain distance from the surface 
 of the lower mercury. This distance, at the mean level of 
 the earth's surface, is about thirty inches. It varies accord- 
 ing to altitude. 
 
 In the usual process of constructing barometers, the tube 
 is filled with mercury, and its lower end immersed in a 
 basin of the same fluid, technically called the cistern. The 
 mercury falls from the top of the tube to the limit of its 
 suspension ; and as much as falls from the tube is raised in 
 the cistern. As much mercury is elevated in the cistern as 
 is depressed in the tube ; the descent and ascent are exactly 
 equal. In all subsequent changes the fall of mercury is 
 equal to the rise, particle for particle ; the flow of mercury 
 back and forth makes the same relative change in the 
 
MECHANICAL PHILOSOPHY. 125 
 
 volumes of the tube and cistern mercury. A perfect equi- 
 librium was at first established by the ascent of a quantity 
 of mercury in the cistern exactly equal in amount to that 
 which descended in the tube, and the equilibrium is ever 
 sustained by the same process, without reference to atmo- 
 spheric pressure. 
 
 With this perfectly balanced instrument the atmosphere 
 is supposed to be weighed. It is in one scale, but no test 
 weight is put in the other scale. The air is weighed 
 against nothing. All the ponderable matter hangs on one 
 arm of an evenly balanced lever, and its weight is to be 
 ascertained by the degree of the ascent of the other arm. 
 Place on the outer mercury an additional pound of the 
 fluid, the mercury in the tube will not rise so as to weigh a 
 pound more ; add to the density of the air over the outer 
 mercury, the rise in the tube will not correspond to the 
 increased weight of air on or over the cistern. When we 
 added mercury to that in the cistern, the mercury in the 
 tube rose just enough to maintain its former distance from 
 the lower surface. When the tube was first plunged in the 
 cistern, it made no difference how great or how little was the 
 quantity of mercury in the cistern ; it makes no difference 
 afterwards whether mercury be added or taken away ; the 
 same distance will be preserved between the two surfaces. 
 The rise of the fluid in the tube will not, therefore, measure 
 the weight in and on the cistern. 
 
 It will be said, however, that though, when an additional 
 pound of mercury is placed in the cistern, an equivalent 
 pound does not rise in the tube, enough rises inside to cor- 
 respond with the increased height outside, and therefore it 
 weighs a column of mercury resting on the surface of the 
 outside mercury, which is of the same area as itself, and 
 
126 OUTLINES OF A SYSTEM OP 
 
 consequently, in weighing the air over the cistern, it weighs 
 a column of air of its own area only. 
 
 This idea is a mere statement of facts. The result 
 empirically obtained is exalted into a principle, and one 
 which is at variance with all other principles of the action 
 of fluids. Fill a cylinder with mercury, and from the cylin- 
 der let a long tube ascend; subject the mercury in the 
 cylinder to the pressure of a piston, and the rise of the mer- 
 cury in this tube, that is, the weight of the mercury sup- 
 ported by the pressure of the piston will be measured by the 
 whole pressure of the piston, not by its pressure on a sur- 
 face of mercury in the cylinder, equal merely to the area of 
 the tube in which the mercury is supported. So if the rise 
 and fall of the mercury in the barometer are proportional to 
 the weight of the air, they are so to the weight of all the air 
 over the cistern ; but, as it makes no difference in the ac- 
 tion of the barometer whether the surface of the cistern is of 
 two inches area, bearing a column of air of two inches area, 
 or is an ocean of mercury, bearing the atmosphere of a hemi- 
 sphere, we are compelled to look for some reason besides 
 the weight of the air to account for the fact, that the two 
 surfaces of fluid in the barometer preserve a fixed distance 
 between them. In other words, the variation in the length 
 of the column of mercury is not determined by a correspond- 
 ing variation in the density of the air. 
 
 In the use of mercury to indicate the pressure of steam, 
 or of the condensed air of blowing cylinders, the extent of its 
 rise in the indicating tube corresponds to the extent of the 
 surface of mercury exposed to it. In a steam gauge the area 
 of mercury exposed to the pressure of the steam bears such 
 a proportion to the area of mercury in the indicating tube, 
 that the usual range of force is measured by its rise and fall. 
 
MECHANICAL PHILOSOPHY. 127 
 
 Now, enlarge the surface exposed to the action of the steam, 
 give it an area equal to the area of the piston, the gauge 
 would burst by the increased pressure, and the mercury be 
 thrown with violence in all directions. Take out the baro- 
 metrical tube from its cistern, and place it in an ocean of 
 mercury, its range would not change, the two surfaces 
 would still remain at the same distance apart. 
 
 Why does the mercury select one column of air of its own 
 area and answer to its pressure, regardless of the pressure 
 of a hundred other columns of the same size and weight 
 which bear upon the cistern ? It cannot be from the uni- 
 form bore of the tube ; for the tube may be unequal, either 
 contracted or enlarged ; it may be a cone with its base 
 downward, or a cone with its base upward ; the aperture 
 or opening between the tube and cistern may be larger or 
 smaller than the bore of the tube ; the relative quantity of 
 the mercury in the cistern may be such, that on bringing 
 the instrument to a lower level it will nearly all be drawn 
 into the tube, and yet will remain suspended, so that in this 
 case, if the mercury is sustained at all by the atmosphere, 
 it is by a column of less area than the bore of the tube 
 pressing on the small orifice between the tube and cistern. 
 There is indeed nothing in the action of the barometer which 
 proves that the mercury in the tube is sustained by a column 
 of air of its own area. 
 
 Further ; if it were possible that the sustained mercury 
 under any circumstances could select a column of air of its 
 own area, out of a volume of air pressing by elasticity in every 
 direction, and disregard the pressure, weight and elasticity of 
 other columns which act on the surface of the cistern, yet 
 it would be impossible as the barometer is usually con- 
 structed. The cistern is closed at top ; its bottom is a piece 
 
128 OUTLINES OF A SYSTEM OF 
 
 of leather ; the instrument is inclosed in a wooden case and 
 suspended perhaps in a close room. It then receives the 
 pressure or weight of its selected column of air forty-five 
 miles high, one quarter of an inch in diameter, which may 
 be twisted and beat about by the winds of heaven, and 
 reaches the instrument through doors or windows, passing 
 through the air in the room, which is subject to expansion and 
 condensation by artificial changes of heat. Yet, not affected 
 by these changes, it penetrates through the openings of the 
 wooden case, acts on the bottom of the leathern support, and 
 still gives exactly the degree of pressure belonging to its 
 area, to the mercury in the tube through an aperture of 
 any size ! Is it possible that any thing can be measured 
 by such an instrument, except, perhaps, the elasticity of the 
 air in the apartment in which it stands, which would affect 
 the whole extent of the surface of the mercury on which it 
 acts? 
 
 But if this last and only possible action of the air by its 
 elasticity be the cause of the oscillation, why is it that two 
 upper surfaces of mercury, one in the cistern and one in 
 the tube, are an essential condition of the oscillation ? A 
 tube in a conoidal form with a piece of leather over its base, 
 would as well indicate the pressure of the atmosphere. The 
 leather would act as well thus placed. It would have the 
 same elasticity. The air pressing on it would act as truly 
 without an upper surface of mercury as with it. The fact 
 that two upper surfaces of the fluid are necessary, abun- 
 dantly proves that another cause for the action of the 
 barometer is yet to be discovered. 
 
 In our examination of the action of the pump and of the 
 syphon, we hope to throw more light on the subject of the 
 elevation and support of fluids by means of a vacuum. 
 
MECHANICAL PHILOSOPHY. 129 
 
 Surely enough has been already said to throw a strong sus- 
 picion over the theory which explains barometric action by 
 atmospheric pressure. Indeed, the explanation has often 
 been received with some distrust. A friend, whose strength 
 of mind was never questioned, said, " I have believed the 
 explanation, relying on the authority which gives it, rather 
 than because it satisfies my mind ; there is something about 
 the action of the barometer which is not yet understood." 
 
 If both the construction of the barometer and the quali- 
 ties of the atmosphere are such as to throw great doubts 
 over the supposed action of the weight of the air on the 
 mercury, how much are these doubts increased when it is 
 known that the mercury changes its level in the tube, under 
 circumstances which forbid the idea that there have been 
 equivalent changes in the density of the air ? To place this 
 matter in a strong light, we will give the following state- 
 ment from Humboldt's Cosmos : " The horary oscilla- 
 tions of the barometer between the tropics present two 
 maxima, namely, at 9 or 9 A. M., and 10J or lOf P. M. ; 
 and two minima, at 4 or 4|, P. M., and 4 A. M., occurring, 
 therefore, in almost the hottest and coldest hours. Their 
 regularity is so great that, in the daytime especially, the 
 hour may be ascertained from the height of the mercurial 
 column without an error, on the average, of more than fif- 
 teen or seventeen minutes. In the torrid zones of the New 
 Continent, on the coasts, as well as at elevations of nearly 
 thirteen thousand feet above the level of the sea, where the 
 mean temperature falls to 44 6', I have found the regular- 
 ity of the ebb and flow of the aerial ocean undisturbed by 
 storms, hurricanes, rain, and earthquakes." 
 
 Can we receive the idea conveyed in the latter clause of 
 this quotation ? If there is an ebb and flow of the aerial 
 
130 OUTLINES OF A SYSTEM OP 
 
 ocean, is it possible that its regularity should remain undis- 
 turbed by storms and hurricanes ? 
 
 If the oscillations of the barometer day after day, month 
 after month, are as regular and uniform as the beating of 
 the pendulum of the clock, these changes come not from the 
 capricious, fitful alterations of the state of the air. The 
 action of the most unrestrained element in nature gives not 
 results the most exact and most regularly continued. If, 
 as Humboldt expressly states, the horary oscillations of the 
 barometer are not affected by changes of atmospheric tem- 
 perature, neither by heat nor by cold, by snow nor by rain, 
 by storm nor by calm, by the peace of nature nor by the 
 throe of the elements, if the changes go on regularly and 
 periodically on the plains and on the tops of high mountains, 
 surely it is vain to seek in the variations of atmospheric 
 pressure the cause of these oscillations. 
 
 Geologists have often noticed that the changes of the 
 level of different portions of the earth are complementary. 
 There is a rise in one place corresponding to the fall in 
 another place ; for instance, an elevation taking place in 
 Sweden is responded to by a depression in Iceland. Be 
 Beaumont calls this the " mouvement de bascule." Besides 
 these occasional movements resulting in permanent change, 
 we believe that there are periodical fluctuations of the surface 
 of the earth of this compensatory nature, occasioned by the 
 varying distribution of the force by which she moves in her 
 orbit. This fluctuation would enlarge the earth in one 
 diameter, and contract the diameter at right angles with this. 
 Thus there are two daily elevations and depressions corres- 
 ponding with each other. This gives the two maxima and 
 minima of the barometer. 
 
 The elliptical form of the earth's circumference is depend- 
 
MECHANICAL PHILOSOPHY. 131 
 
 ent on her position as being nearer to, or further from the 
 centre of revolution ; and the shrinking or expansion is regu. 
 larly propagated by her rotation. The movement being 
 oscillatory, the maxima will, of course, be somewhat after 
 noon and midnight, corresponding with the minima of the 
 barometer. The extreme would also be greatest within the 
 tropics. Connected with this subject are the horary changes 
 of the horizontal magnetic intensity, to which we shall here- 
 after allude. 
 
 To one other fact only will we at this time advert. It is 
 stated, on good authority, that the barometer is more to be 
 depended on for determining heights, than trigonometrical 
 observations are. The reason given is, that " the refraction of 
 the air prevents accurate measurements of the angle." If 
 we are correct, the reason is obvious ; but it is impossible that 
 the density of the atmosphere should, under all disturbing 
 influences, always correspond to elevation with a greater 
 accuracy than the results of geometric calculation. 
 
 In our attempt to explain the cause of the action of the 
 barometer, we can, in this place, but imperfectly advance the 
 views that have presented themselves. These views involve 
 peculiar ideas, not only in regard to the force of rotation 
 and revolution, but to the vacuum, to the action of fluids in 
 relation to their own particles, and to their action in relation 
 to other matter ; and the ideas, to be presented with any 
 distinctness, must be gradually unfolded as we proceed. 
 
 The changes of the mercury result in a longer or shorter 
 column of the fluid in rotation as one mass. In the rotation 
 of any one mass, the force of rotation is unequally diffused 
 through it ; the parts, say the upper and the lower, rotate 
 with greater and less force. This inequality of present 
 force increases with the distance of the two surfaces. It 
 
132 OUTLINES OF A SYSTEM OF 
 
 increases also with the density of the mass, the distance be- 
 tween the surfaces remaining the same ; it increases by a 
 greater degree of rotative velocity, in a mass of the same 
 density and same distance of the two surfaces. In other 
 words, while the ratio of difference remains the same between 
 the different parts of the same body, the actual inequality is 
 increased by increased extension, or density, or velocity. 
 
 "We have, then, an unequally distributed rotative force 
 present in every mass, and the extent of the inequality is in 
 direct proportion to the difference of the orbit of the upper 
 and lower extremities, to the density of the body, and to the 
 velocity of its rotation. 
 
 In solids bound together by cohesion, in fluids so placed 
 that the upper and lower surfaces cannot approach or draw 
 apart, this inequality must and will continue, whatever be 
 their depth, density, or velocity of rotation. But from the 
 law of the diffusion of force, there is a normal difference of 
 diffusion to which all fluid bodies conform when free to 
 adjust their volume in relation to it. 
 
 From this principle comes what we term the limit of ex- 
 tension of fluids, a distance between the upper and lower 
 surfaces, which measures the normal inequality of the pre- 
 sent force, an idea which we hope fully to illustrate as we 
 proceed. At present we merely state the fact. The limit 
 is perceived only in fluids so placed that a change can be 
 made in the length of the column. This is the case with 
 the mercury in the barometer. It can shorten or lengthen 
 its column, and it must have the upper and lower surfaces 
 to effect this. It keeps the normal inequality the same 
 under any force of rotation, by extending or lessening the 
 distance between the two surfaces. It rotates with a column 
 which corresponds in length to the force of rotation. If the 
 
MECHANICAL PHILOSOPHY. 133 
 
 barometer is made with a fluid of less density than mercury, 
 there is the " limit " for the same cause, but it admits of a 
 greater distance between the two surfaces, under the same 
 force of rotation. 
 
 We dismiss the special consideration of the barometer, with 
 a most unhesitating belief that its action is caused by the 
 increase or diminution of the force of rotation, that in its 
 changes it denotes its level, that it indicates directly the 
 altitude. We believe so from the fact that such would be 
 its action as deduced from principles established in our mind 
 on other grounds. We also believe so, because we find 
 the oscillations always to be such as could be occasioned by 
 changes of level, and often such as could never be produced 
 by varying densities of the atmosphere ; and because, if the 
 atmosphere be of varying density, the construction of the 
 barometer is such that it could not be affected by the varia- 
 tion. We solicit a thorough examination of this subject ; 
 for, if we are correct, it gives a value to the instrument far 
 greater than it now possesses, its readings being at present 
 confined to atmospheric pressure. 
 
 We pass from the barometer, hoping further to elucidate 
 its action by examining the limit of extension in relation 
 to water. The principle is the same in every fluid ; but 
 water, for many obvious reasons, most distinctly illustrates 
 the opinions that we would present. 
 
 Water, in a tube closed at the top and open at the bot- 
 tom, on being immersed in water will remain suspended at 
 any height within the limit. But if the top of the tube be 
 opened and air be allowed to enter it, the inclosed water 
 will sink to the level of the water in which the tube is im- 
 mersed. The exclusion of air from the tube is, therefore, 
 12 
 
134 OUTLINES OF A SYSTEM OF 
 
 the condition requisite for the water in it to remain above 
 the level of the water in which it stands. This appears of 
 easy explanation. When a volume of water is in contact 
 with air, the surface of this volume of water, if at rest, will 
 be of uniform level. In the two elements, air and water, 
 there is a difference of capacity for force, so that the one, 
 when in contact with the other, invariably retains a fixed 
 degree of force relative to the other. This principle gives 
 uniformity of level to the surface ef any volume of water in 
 contact with air ; but, if any part of its upper surface is with- 
 out this contact, its level of rotation does not depend on that 
 which gives level to the parts of the surface of the water 
 which are in contact with the air. 
 
 Under the theory of gravitation it is supposed that it is 
 the weight- of the atmosphere on the water outside of the 
 tube, and its absence within it, which create the inequality 
 of pressure, resulting in the elevation and support of the 
 water in the tube. This is supposed to be shown by the 
 action of the atmospheric pump, by the syphon, and in fact 
 by all the cases of the elevation of w r ater which exhibit the 
 law of extension. It is considered as occasioned by the 
 vacuum, fluids being suspended because of a vacuum, or 
 because there would be a vacuum if the fluid did not ascend. 
 
 The idea is not distinctly advanced at the present day that 
 the action of the fluid is from an attractive power of the va- 
 cuum ; but the inference necessarily drawn from the facts in 
 connection with present theories is, that nature so abhors a 
 vacuum that action is immediately induced, not only to fill 
 the vacuum formed, but to prevent it from being formed. 
 There is always a supposition of aid from the weight of an 
 outside column of air, of the same area as the column of 
 heavier fluid to be acted upon ; but in no case can the action 
 
MECHANICAL PHILOSOPHY. 135 
 
 of this external counterpoise be proved, and in many cases it 
 is certain that it does not exist or act. In a succeeding 
 chapter, when speaking of the properties of air, we shall 
 endeavor to illustrate the principle, by which a vacuum arti- 
 ficially created, as it were, draws in matter to fill the void 
 space. In our present view of the subject, we confine our- 
 selves to the illustration of the idea, that the support of a 
 column of fluid within the limit of extension does not and 
 cannot depend on the pressure of a column of air of its own 
 area. 
 
 We will suppose a common atmospheric pump, working 
 with perfect nicety, and with the least possible friction. 
 The piston is in contact with the surface of the water to be 
 raised, and on being lifted the water is raised with it. There 
 is no vacuum here ; the atmosphere rests on the piston, and 
 the piston on the water, and this mutual relation of atmo- 
 sphere, piston, and water continues. The piston and the 
 water below it are not in the least relieved of the weight of 
 the aerial column over them ; if it pressed on the piston be- 
 fore it was moved, it equally presses when it is moving 
 upward. If the pressure of an equal column of air on the 
 water of the cistern raises the water in the pump, its action 
 prevents a vacuum from being formed. We make for the 
 present the simple statement, that force applied to the water 
 gives it power to rise to a higher level, and the elevation of 
 the piston gives it space, room, freedom to ascend, the 
 needed force for ascent is supplied, and a channel opened 
 for the action of the force. In all similar cases we shall 
 ever find, that when fluids rise in pipes, it is because of the 
 application of force, with space for the action of the force. 
 
 That, in the case of the pump to which we have just 
 alluded, a column of air of the area of the ascending column 
 
136 OULTINES OF A SYSTEM OF 
 
 of water, in other words, atmospheric pressure on the water 
 in the cistern, does not lift up the water in the pump, can 
 be most distinctly proved. We will suppose the piston, 
 which touches the surface of the water, and the elevation of 
 which gives space for the rise of the water, to be securely 
 fastened to the tube, and that the pump, tube, and piston 
 together, be lifted as high as the piston was previously lifted 
 in the pump. The same quantity of water will be raised as 
 before. In the one case, space has been given for the water 
 to rise by elevating the piston ; in the other, by elevating 
 the tube with the stationary piston. The force required to 
 raise the tube, valve and water is just the weight of the tube, 
 valve and water. In either case there needs to be supplied 
 the same degree of force, which would be required to raise 
 a stone of the same weight. How then can it be said, that 
 in working the pump, the pressure of the atmosphere is the 
 elevating power, when for every pound of water raised the 
 force necessary to raise a pound is required ? 
 
 It is said in Ewbank's Hydraulics that the pump will 
 work " if the well be covered with slabs of stone, and 
 coated all over with the best hydraulic cement," thus cut- 
 ting off from the water of the well all pressure of the atmo- 
 sphere, except such as is drawn by the action of the piston 
 " through the minute pores." The only necessary con- 
 nection with the atmosphere is limited to that orifice, which 
 will admit into the well a volume of air equal to the volume 
 of water withdrawn, otherwise there would certainly be a 
 vacuum formed in the well. No connection whatever be- 
 tween the atmosphere and well is needed, if the water ele- 
 vated runs back through another pipe into the well. The 
 act of pumping is the establishment of a current of water. 
 It has no connection whatever with atmospheric pressure. 
 
MECHANICAL PHILOSOPHY. 137 
 
 A pump would work completely immersed under water, 
 there establishing a connected current, and after the cur- 
 rent was formed the upper surface of the water would not 
 be even ruffled, the atmosphere pressing equally on all the 
 parts of the current below. 
 
 It is said that the atmosphere presses on the body of 
 every man with a force of some fifteen tons, but because it 
 bears equally in every direction, because it is so exactly 
 equipoised, it is not an object of sensation. We do not 
 feel it. Its force is neutralized, destroyed, so far at least 
 that it induces no perceptible results. This is true, not 
 only in relation to the human body, but to every mass of 
 matter immersed in air. The cistern and the water that it 
 contains, the valves, the water in the tube, and the jet of 
 water issuing from the tube, are as one body ; the enfolding 
 atmosphere is wrapped around the whole with equal strain. 
 If the pressure of the air has power to cause the water to 
 ascend through the tube, it has the same power to act in 
 the opposite direction. If it press water in at the bottom 
 of the tube, why does it not press it back with equal force ? 
 When the upward current is established in the pump, all the 
 force to create the current must be supplied ; the force 
 needed is exactly equivalent to the weight of water elevated. 
 Therefore, the doctrine of equal areas of atmosphere sup- 
 porting the denser fluid in vacuo has no more application to 
 the raising of water by the pump, than it has to the drawing 
 of water from a well by the pole and bucket. By both 
 mechanical means strength is put forth proportional to the 
 quantity of water to be raised, and to the distance of eleva- 
 tion, the weight of the atmosphere, so far as any practical 
 result is concerned, being neutralized, destroyed, by the 
 affirmed law of its equal pressure in every direction. 
 
 12* 
 
138 
 
 OUTLINES OF A SYSTEM OF 
 
 But for the skeptical we will mention a fact which per- 
 fectly demonstrates that the action of the pump has no 
 reference to the pressure of the atmosphere. By accident, 
 in Seville, in 1766, it was discovered that water could be 
 raised by the pump fifty feet and more, if a small opening 
 was made for the admission of air into the tube of the pump. 
 This circumstance excited great attention at the time, and 
 was supposed to prove that water could be raised by atmo- 
 spheric pressure much higher than thirty-three feet. 
 
 In the Journal of the Franklin Institute for May, 1837, 
 it is stated with reference to the action of pumps worked by 
 steam, that a little air is sometimes admitted into the pump 
 pipes, which " makes the pump work more lively in conse- 
 quence of the spring it gives to the column of water." And 
 in the same paper, Mr. Perkins states, that " forty years 
 before an attempt was made to impose upon him a pump 
 which raised water by atmospheric pressure one hundred 
 feet ; but he detected a small pin hole in the pipe through 
 which the air was admitted." 
 
 These facts are fatal to the theory that atmospheric press- 
 ure causes the elevation of water in pumps ; for there may 
 be the pressure on the ascending as well as on the impelling 
 column. No matter how little this pressure is, though the 
 fact was shown in Ewbank's well, closed by hydraulic cement, 
 that the pressure through small apertures is as strong as 
 through large, if the pressure within was but an hundredth 
 part of that without, what there was of it would balance pro- 
 portionally the external pressure, and to this extent too it 
 would impair the vacuum ; but instead of this it gives new 
 power of ascent to the water, more than doubling the possi- 
 ble extent of its elevation. To account for this we are told, 
 " It was ascertained, on investigation of these facts, that the 
 
MECHANICAL PHILOSOPHY. 139 
 
 air on entering the pipe mixed with the water, which there- 
 fore, instead of being carried up in an unbroken column, 
 was raised in disjointed portions or in the form of thick rain. 
 This mixture being much lighter than water could be sup- 
 ported by the atmosphere, and by proportioning the quantity 
 of air to be admitted, a column of the compound fluid may 
 be elevated one or two hundred feet by the atmosphere." 
 In this explanation the fact seems to be forgotten, that it is 
 not the weight of the column of water which determines the 
 altitude to which it can be raised. Increase the force, and 
 ten thousand pounds may be lifted as readily as ten pounds. 
 It is the height of water, not the weight, which attained, it 
 will no longer rise ; and the main fact was quite forgotten, 
 that atmospheric pressure was at work as well within as 
 without the tube. 
 
 Our views can be presented more distinctly by reference 
 to the action of the syphon. In the pump the current is 
 established by animal force, or by the power of wind, steam, 
 &c. applied to the piston ; in the syphon the same end is 
 obtained by the presence of a longer column of water in one 
 leg than in the other. To use the common language, gravi- 
 tation acting on the longer column with greater force than 
 on the shorter, the equipoise is destroyed, and the water 
 falls in the one, rises in the other, thus establishing a con- 
 tinuous flow. It is the force of descent of one body drawing 
 up another body with which it is connected, as by a rope 
 passing over a wheel. The strength of the flow is therefore 
 determined by the difference in height of the two columns, 
 the force gained by the descent of one being more than 
 sufficient for the elevation of the other. The flow has no 
 reference to the attraction of gravitation ; for by different 
 diameters of the two columns, the quantity or weight of 
 water may be greatest in the shorter leg. 
 
140 OUTLINES OF A SYSTEM OF 
 
 We will suppose a syphon, the shorter leg of which shall 
 be ten feet high, containing a hundred pounds of water, its 
 longer leg of eleven feet containing five pounds of water. 
 The water from the longer leg is discharging itself into the 
 air in a continuous stream. What supports the one hundred 
 pounds of water, which, by theory, is drawn towards the 
 earth by a force equal to its weight, while the water in the 
 longer leg is drawn down by a force of only five pounds ? 
 Certainly it cannot be atmospheric pressure on the larger 
 tube ; for there is also atmospheric pressure at the discharging 
 orifice of the smaller tube. The attraction of the hundred 
 pounds of water, if it be attracted at all, should be suffi- 
 cient to draw up the five pounds and to draw in the air after 
 it. Of course the one hundred pounds does not feel the 
 force of attraction. 
 
 The action of the syphon is therefore but the fall of water 
 through a tube arched upward, and the force of the fall is 
 measured by the difference of altitude between the two 
 levels, that from which it is drawn and that into which it 
 issues. In the pump it appears as if a vacuum were 
 created, as if the current were established by the weight 
 of the air pressing on the water in the well, and not on that 
 in the tube. In the syphon there is not the most remote 
 indication that a vacuum is formed, and the pressure of the 
 atmosphere is exactly the same on the water which enters 
 the pipe, and on that which leaves it. There is no vacuum ; 
 for the syphon is kept full of water, and this creates a plenum 
 as much as if it were filled with lead ; and with the shorter 
 leg immersed in water, the surface of which is at a higher 
 level than that in which the longer leg is immersed, if there 
 be any difference, the atmosphere presses more heavily at the 
 discharging than at the receiving orifice. There can be no 
 
MECHANICAL PHILOSOPHY. 141 
 
 pretence of atmospheric action on a current of water flowing 
 from a higher to a lower level, through a tube arched up- 
 wards. The air in this case has no more to do with the 
 current than if it flowed through a pipe bent downward, or 
 curved laterally, no more than if the water ran down 
 through a straight tube, or without any tube through an 
 orifice in the side of the containing vessel. The action of 
 the syphon is imputed to atmospheric pressure, because the 
 limit to which water can rise in it is the limit, beyond which 
 water cannot be raised in the cases in which atmospheric 
 pressure is supposed to be the cause of the elevation. It is 
 true that if the water at the top of the syphon should part, 
 and it should descend in each column, there would be a 
 vacuum ; but, there being no gravitation, it will not part till 
 beyond the limit of extension. It then parts through the 
 action of the law which regulates the limit. But because, if 
 the syphon does not establish its current, and the water falls 
 in both the legs, there is a vacuum, it does not follow that a 
 vacuum or the dread of one establishes the current when it 
 flows. While the current is flowing there is, if any, an equal 
 pressure at both ends, and from them up through the whole 
 length of the pipe. 
 
 The vacuum is formed, if the syphon be raised above the 
 limit. If the instrument be extended higher, the water does 
 not rise ; but remains elevated at an equal height in both 
 legs, measuring from the respective levels of the surfaces of 
 the water in which they are immersed. It is supposed, that 
 each suspended column is counterpoised by an equal weight 
 of atmosphere, that is, by a column of air of the same area 
 as the suspended column of water. Of course, this being 
 the case, any variation of the limit marks an equivalent 
 change in atmospheric weight. 
 
142 OUTLINES OF A SYSTEM OF 
 
 Without going into the question at this time, of the pos- 
 sible efficacy of the air in sustaining water in such cases, 
 which may well be doubted, as we have seen that it has not 
 the most remote agency in giving it its elevation, we feel 
 confident that the weight of the suspended column does not 
 weigh a column of air of its own area. 
 
 If water be subjected to pressure in a cylinder by a pis- 
 ton acting on its upper surface, the rise of water issuing or 
 sustained by the pressure is measured by the whole amount 
 of the force of the piston, as in the case of a forcing-pump. 
 If the atmosphere presses on the surface of water in a pond, 
 or in a small vessel, the pressure is measurable by the force 
 acting on the whole surface. A pond a mile in area bears 
 the pressure of a column of air a mile in area ; and the 
 water in a small vessel bears the pressure of the column 
 over it. On this principle only can water be acted on by 
 the air, and any variations of pressure arising from atmo- 
 spheric changes would express the variations of the weight 
 of the whole volume of air over the pressed surface. 
 
 Thus far we have considered the limit of extension of 
 fluids, and appear to find that this limit is not determined 
 by the gravitation of the fluid, since the quantity sustained 
 under the same circumstances may be one pound, or one 
 thousand pounds ; nor by the gravitation of the air on the 
 exposed surface of the fluid, since this may be one inch or a 
 thousand miles in area ; nor by any virtue or efficacy of the 
 vacuum, since it may be equally filled, saturated, and thus 
 destroyed by matter of its own volume, whether the matter 
 drawn to fill it is light as air or dense as mercury. The 
 limit is therefore not caused or determined by the gravitat- 
 ing power. 
 
 We advance to a farther consideration, to create the 
 
MECHANICAL PHILOSOPHY. 143 
 
 limit, it is not necessary that the fluid be confined in pipes 
 or vessels. Water out of pipes, unconfined, in the free air, 
 obeys the law. The waters of the ocean respond to this 
 limit. Water-spouts, with mingled air, may raise a broken 
 column to a higher range ; the waves may dash themselves 
 farther up on a rocky coast. Wave may be formed on 
 wave, a new limit of extension may perhaps be formed upon 
 the original limit, an ocean wave upon a tidal wave ; but 
 recorded events always give a height of the rise of floods, 
 which denotes the bound assigned by nature to the heaping 
 up of the waters. 
 
 It is difficult to measure the height of a wave, and impos- 
 sible to separate exactly the unbroken water from the crest 
 which is mingled with air. We know, however, that the rise 
 of waves is less than thirty-four feet in the most violent 
 storm. One measurement taken in a long-continued heavy 
 gale gave thirty-two and a half feet from elevation to de- 
 pression ; on striking a wall of rock, the unbroken column 
 ascended sixty-five feet from the level of the ocean, dashing 
 its spray much higher. The extent of the rise of the tide 
 in the bays of Fundy and of St. Malo is said to be sixty 
 feet, and the reference to heights of which the simple limit 
 forms the root or multiple, in the statements of the rise of 
 floods, is so frequent as to indicate some principle. It is 
 certain, however^that the waves of the ocean have a fixed 
 limit corresponding to the limit of the extension of water in 
 tubes. 
 
 The isolated fact of the limit is thus advanced to an uni- 
 versal principle; 'for it has never been imagined that an 
 unequal atmospheric pressure causes the rise of the waves. 
 Whenever a fluid is so placed that its degree of extension 
 upwards and downwards can be changed or modified, when 
 
144 OUTLINES OF A SYSTEM OF 
 
 it is free to assume its own position, it obeys the law of limit. 
 To give it a greater extension as one mass, it must be re- 
 strained or confined. Its spread or dilation in breadth must 
 be prevented, either artificially as in tubes, or naturally as 
 in a containing basin. Its base must be cut off, it must 
 be separated from other volumes of the same fluid. Water 
 can be elevated to any height by the lifting pump, or by the 
 application in any manner of force beneath the volume of 
 water to be raised. But if the force be applied from above, 
 as in the atmospheric pump, or in any manner to a body of 
 water remaining in connection with other water, the force 
 applied is conveyed away from the special volume to the 
 whole volume ; a portion therefore cannot be elevated. It 
 must first be separated, that the force applied may act upon 
 it. It will then rise ; but before the separation the force 
 applied is communicated to the whole volume. It is thus 
 that separated volumes may be lifted to any height, if suffi- 
 cient force be used ; and this explains the fact before alluded 
 to, that, when air was admitted into the pump by a perfora- 
 tion in the tube, water was lifted beyond the limit, since the 
 air separated the one volume into detached portions. 
 
 The limit of extension is therefore the degree to which 
 fluids can be drawn upward in an unbroken column. It is 
 the limit of the inequality in the distribution of the force of 
 rotation, which will remain when the e^ess can be trans- 
 ferred to another portion of the same volume. It is the 
 limit of elasticity of form ; for while a solid body ever retains 
 one extension, no one part of it being susceptible of ele- 
 vation independently of the other parts of the mass, to raise 
 one part requiring force sufficient to raise the whole, por- 
 tions of fluids can be drawn up, force, to a limited degree, 
 confining itself to the part. Thus, a column of water can 
 
MECHANICAL PHILOSOPHY. 145 
 
 be extended from the volume ; but beyond this limit force no 
 longer confines itself to the part to which it is applied, but 
 diffuses itself through the whole volume. Therefore, the 
 sea knows its place ; the level of the waters composing 
 so large a relative portion of the globe is preserved, not 
 with a dead uniformity, not with a rigid flatness of sur- 
 face, but with constant changes, limited undulations ; and 
 the ocean, free to move, yet under the law of extension, is 
 as securely bound, as are the rocky cliffs against which its 
 rolling surface strikes. 
 
 The more our attention is directed to the unfathomable 
 deep, the more wonderful appears the action of the laws 
 which control it. We are taught to regard the vaporization 
 of the surface of the ocean as a means by which the equili- 
 brium of heat is preserved, and by which the waters circu- 
 late from the sea to the clouds, from the clouds to the 
 thirsty earth, and again collecting in swelling streams return 
 back to the ocean in a never-ceasing flow. How great the 
 quantity of fluid thus in constant change, hundreds of 
 millions of tons rising in one day from the comparatively 
 small extent of the Mediterranean Sea, the quantity ever 
 rising from the entire surface of the waters of the globe, 
 from the frozen polar seas, as well as from the tepid oceans 
 of the torrid zones, being beyond all estimate ! 
 
 This vaporization not only waters the earth, not only 
 restores the equilibrium of temperature, these effects being 
 as it were the incidental mercy of the law of nature ; but 
 it is the preservation of an equilibrium si force. The ocean 
 exhausts itself of the strength not necessary for its level of 
 motion, the vapor draws off the excess of energy, and the 
 waters preserve their equable flow. The risen vapor, again 
 condensing, slowly imparts a quickening impulse to the slug- 
 is 
 
146 OUTLINES OF A SYSTEM OF 
 
 gishly moving air, or rapidly throws out the force in the light- 
 ning's flash, giving to some portion of the earth the needed 
 impulse. For this reason is there greater condensation, 
 more copious rain, in high lands and mountainous regions, 
 which from their elevation require the added force. 
 
 No one can contemplate the extent of the oceans of the 
 globe, their vast surface compared with the land, without 
 being assured that this unequal distribution is not from acci- 
 dent, without the belief that there is connected with it the 
 furtherance of some great design. And when we consider 
 its relations to force, its strong conducting power, we see a 
 reason for the ocean's vastness, and comprehend its action in 
 the economy of nature. There is a reason too for the pre- 
 ponderance of water in the southern over the northern 
 hemisphere, which may yet be discovered by man ; for, 
 though land and water seem confusedly mingled as if with- 
 out law, not by accident came the position of the smallest 
 island, nor the bounds of the paltriest lake. 
 
 Then again, the waters of the ocean have a molecular 
 action, increasing in intensity as they deepen. The experi- 
 ments of Scoresby, the well-known fact of the breaking of 
 a vessel containing air when let down to a certain depth, 
 the bursting of a tight, full cask, by the insertion of a long 
 slender tube filled with water, the "spring" of water, of 
 which mechanics take advantage in their management of 
 water-power, by narrowing the aperture through which the 
 water flows, the eflect of conical ajutages, by which the 
 flow of water from a discharging orifice is greatly increased 
 from the transfer of the molecular action into the progressive 
 motion of the moving jet, all these facts together prove 
 that there is an increase of the atomic action of water pro- 
 portional to the distance from the surface, and that this 
 
MECHANICAL PHILOSOPHY. 147 
 
 change is not in the least dependent on a force of gravita- 
 tion ; for water is almost incompressible, and, were it com- 
 pressed, the increase of molecular action is altogether too 
 rapid for the rate of increase of gravitation, according to 
 the distance from the centre. 
 
 Thus the waters receive and retain a greater force than 
 is needed for rotation, resolving it into molecular action, the 
 ocean becoming, as it were, the storehouse of force, from 
 which it may be gradually imparted according as it is 
 needed for the motions of the various parts of the earth. 
 It is by this provision that force divides or diffuses itself 
 equally throughout the volume of the fluid ; for, as stratum 
 after stratum requires the less for rotation, the unused force 
 is employed in molecular motion. It is by this equal diffu- 
 sion that the movable element preserves its continuity ; and, 
 without the bonds of cohesion to hold its particles together, 
 it moves with the earth as one mass, no portion ever raising 
 itself beyond the limit, or floating in the atmosphere in 
 detached masses. Without this provision, the air would not 
 be divided from the waters, element would not be separated 
 from element, the waters could not be gathered together into 
 one place. 
 
 It appears evident, then, that there is in water and other 
 fluids a molecular action, which increases in intensity accord- 
 ing to the depth, or distance from the surface. On the other 
 hand, the rotative force increases as it ascends from the 
 depths, being greatest at the surface. One therefore is the 
 complement of the other, each being capable of resolution 
 into the other. Therefore, force is ever equally diffused 
 through the same volume, the aggregate of force being 
 evenly distributed through each body of water, whatever its 
 depth or extent. It is therefore equal throughout the space 
 occupied by the water. 
 
148 OUTLINES OF A SYSTEM OF 
 
 How far extends this principle of the equal distribution of 
 force relative to space ? Is it universal, in solids and fluids, 
 from the densest matter to that which makes the nearest 
 approach to a vacuum ? Do accelerated and retarded motion 
 take place from the adjustments of force, as in different 
 degrees it acts in the atoms and in the mass, in the mole- 
 cular and the progressive motion ? Is it a normal adjust- 
 ment which gives harmony of movement to the spheres ? 
 Is motion irrespective of mass ? Has the rarer medium 
 of the atmosphere, for instance, an increase of molecular 
 action to compensate, as it were, for its less quantity of 
 progressive motion in a given space ? This indeed opens a 
 wide range of thought ; but we pause in the inquiry. May 
 we not hope that in time to come the intellect of man may 
 be able to penetrate these mysteries, and to find in the 
 now complicated phenomena of motion that simplicity and 
 comprehensibility, which belong to every domain of nature ? 
 If force be equally diffused through space, and we extend 
 the idea of the equality of its diffusion to limitless space, 
 the human mind almost shrinks back at the contemplation 
 of this expanse of energy. There is but one step farther 
 which it can take, going on from boundless force to Him 
 from whom it is the emanation. 
 
 To return : there is then by fixed laws a permanence 
 given to the free-moving elements. There is a defined limit 
 of extension, measured by the density of the fluid, and by 
 the velocity of its motion. This is determined by the degree 
 of the inequality of force which will be retained by any 
 volume of fluid, so placed that it can transfer the added 
 force. Broken columns of water may be elevated to any 
 range of rotation ; but water resting on water as its base, 
 refuses to extend itself, or to be drawn out above its normal 
 
MECHANICAL PHILOSOPHY. 149 
 
 range. Beyond this, force -will not so adjust itself as to 
 keep it one mass ; if you apply force, the water receives 
 it, but will not retain it. The raging storm passing over the 
 wide ocean, ever imparting force, gives to the water a defi- 
 nite range of altitude only, while the excess is silently trans- 
 ferred to the deeps below. Urge it further and further, it 
 still refuses to rise, and, if saturated, if it can retain no more 
 in the intensity of molecular action, the water at the surface 
 changes into vapor and floats upward in harmless cloud- 
 wreaths. 
 
 " And God said, I will establish my covenant with you, 
 neither shall all flesh be cut off any more by the waters of a 
 flood, neither shall there any more be a flood to destroy the 
 earth. I do set my bow in the clouds, and it shall be for a 
 token of a covenant between me and the earth." 
 
 The bow in the cloud has been by many looked upon as 
 a figure of speech only, as a beautiful metaphor, possessing 
 no more significance than the clear sunshine after the falling 
 rain. It has not been connected in men's minds with any 
 law of nature, which determines the limit of the rise of the 
 waters. Yet it is the expression of the law by which the 
 floods keep their place. It connects science with the writ- 
 ten Word. Understood, the rainbow shows the harmony of 
 the creation with the voice of God. It practically as well 
 as spiritually records the covenant. 
 
 The water ascends from its immense ocean bed only as 
 the vapor of the clouds. It cannot rise to deluge the earth. 
 The flowing stands firm, the free moving element is bound 
 in chains ; for though intense force, in its might, may rush 
 across the rolling waves, it will not impart to them the power 
 to rise above a fixed limit, except as vapor, and on the 
 
 13* 
 
150 
 
 clouds the covenant is written in the vivid colors of the rays 
 of the sun. 
 
 Devoutly thankful should we be when reason thus re- 
 echoes the voice of God, when science, in her feeble 
 utterance, repeats the declarations of Scripture. 
 
 We cannot, with the thought of this connection, look upon 
 the bow in the clouds but with increased delight, and with a 
 strengthened reverence for the written Word, with some- 
 what of the feeling which prompted the exclamation of Cole- 
 ridge, " What a mine of undiscovered treasures, what a new 
 world of power and truth, does the Bible promise to our future 
 meditation, when in some gracious moment, one solitary text 
 of all its inspired contents dawns upon us in the pure un- 
 troubled brightness of an idea, which even as the light, its 
 material symbol, reflects itself from a thousand surfaces! " 
 
CHAPTER VII. 
 
 "THERE ARE INDEED MANY THINGS IN THE FRAME OF NATURE, WHICH 
 WE CANNOT REACH TO THE REASONS OF, THEY BEING MADE BY A 
 KNOWLEDGE FAR SUPERIOR AND TRANSCENDENT TO THAT OF OURS, 
 AND OUR EXPERIENCE AND RATIOCINATION BUT SLOWLY DISCOVER- 
 ING THE CONTRIVANCES OF PROVIDENCE THEREIN. 
 
 "NO MAN EVER WAS OR CAN BE DECEIVED IN TAKING THAT FOR A 
 TRUTH WHICH HE CLEARLY AND DISTINCTLY APPREHENDS, BUT ONLY 
 IN ASSENTING TO THINGS NOT CLEARLY APPREHENDED BY HIM." 
 Cudworth. 
 
 WE continue our examination of the action of force upon 
 fluids. Our views bring us to the conclusion that there is 
 no weight or pressure of the particles of water against each 
 other, against a containing vessel, or against a foreign body 
 immersed, other than arises from the force of molecular 
 action, which manifests itself under certain circumstances. 
 We do not believe that gravitation presses together the 
 particles of water, or presses them against an immersed 
 body. 
 
 This proposition at first sight appears to contradict the 
 generally received opinions on the subject. It is not so. 
 Though expressed in different language, our proposition is in 
 harmony with established views. The law of gravitation is 
 modified in its application to fluids. It is said, u the par- 
 ticles of fluids gravitate independently of each other, not 
 only downwards, but upwards and sideways." " The press- 
 ure of fluids is equal in all directions, being founded on the 
 
152 OUTLINES OF A SYSTEM OF 
 
 complete intermobility of the particles of the fluid, and on 
 the equal propagation of pressure in every direction." 
 " When a fluid is at rest the pressure will be nothing, be- 
 cause the opposite dead pressures will be equal." These 
 quotations are from the highest authority, and completely 
 prove the proposition with which this chapter commences, 
 so far at least as relates to any result from the pressure. 
 
 Admitting, however, the theory that the atoms of water 
 do press against each other, and against an immersed body, 
 the pressure, if it is equal in every direction, cannot proceed 
 from an attraction of gravitation drawing towards the centre 
 of the earth. Why this equal pressure, of the existence of 
 which there can be no proof, is attributed to a force acting 
 downward only, does not appear. 
 
 A consideration of the weight of a mass of matter rigidly 
 at one level, or of the pressure of one mass against another, 
 or of the mutual pressure of their atoms when relatively at 
 perfect rest, involves what may be called transcendental 
 dynamics. It treats of a tendency to fall, a tendency of 
 the particles of matter to move against each other, which 
 is followed by no action. The tendency to fall, of a body 
 secured so rigidly that it cannot be moved, can never be the 
 subject of experiment. We can measure force only by 
 resultant motion. There is no force of descent unless there 
 is a descent. A body secured at one level at perfect rest, 
 would feel heavy only by the upward pressure of the hand 
 against it. Suppose a body which by its fall presses a spiral 
 spring, the weight of the body is its force of descent upon the 
 spring, which, if it have not force of elasticity enough to 
 throw it back, will remain compressed. The compression is 
 a change in the position and arrangement of the atoms com- 
 posing the spring. This comparison will indicate the reason 
 
MECHANICAL PHILOSOPHY. 153 
 
 of the feeling of pressure in the hand supporting any mass 
 of matter. 
 
 We will suppose a vessel ten feet high containing water. 
 From an aperture near the upper surface the water will 
 run with but little force, falling down almost perpendic- 
 ularly ; from an aperture in the middle it spouts with con- 
 siderable power ; and from one at the bottom the flow is 
 with greatly increased energy. The jet is horizontal in 
 proportion to the distance of the orifice from the upper sur- 
 face ; its force is in proportion to the descent of the water 
 inside the vessel. There is little or no force of descent in 
 the water flowing from the upper orifice, the whole force of 
 descent is in that flowing from the lower opening. It is the 
 force of descent which impels the water, not abstract weight 
 or tendency to descend ; for a pound of water at the surface 
 has as much desire to go down, is as much attracted, as a 
 pound at the bottom of the vessel, that is, neither is at- 
 tracted to the earth. Matter itself is inert, without power 
 to move or tendency to move. It obeys the law of force, 
 and if absolutely at rest it is without force ; nothing can be 
 affirmed of it, but that it is, the fact that it exists in 
 space. We proceed to more practical illustrations of the 
 pressure and equilibrium of fluids. 
 
 We will describe from nature. We were leaning on the 
 rail of a bridge, a few rods above which rose a dam about 
 ten feet in height, which held back a pond of water extend- 
 ing beyond the dam for at least a mile. The dam was per- 
 haps two hundred feet long, it was old and dilapidated, 
 and from between the logs there were at every height 
 countless jets of water. On the top of the dam was a flash 
 board. a plank placed edgewise, slightly secured, to in- 
 crease the height of the dam. At one place this flash board 
 
154 OUTLINES OF A SYSTEM OF 
 
 had given way, and there the water poured over the dam in 
 an unbroken sheet. We will look at this dam with its many 
 jets of water, the broad sheet tumbling over a part of it, to 
 understand the nature of the pressure of water. It will give 
 us the truth, if observed with minds free'from all predeter- 
 mined theories. 
 
 In the first place, we see that the water does not press 
 equally in all directions, upward, downward and sideways ; 
 for the lower jets of water issue with much more force 
 than the upper jets. There is a gradual diminution of 
 pressure from the lowest to the highest ; the top of the 
 water falling over the dam does not press at all, for the sur- 
 face retreats, forming a curve. The pressure increases 
 from the surface to the bottom. Fluids do not gravitate 
 equally in every direction, or the force of gravitation would 
 have thrown out equal jets from the top to the bottom. 
 Perhaps the water gravitates downward only. That cannot 
 be the case ; for then there would be no lateral pressure, 
 but at each jet the water would flow nearly without force. 
 One other thing is certain, that this great volume of water, 
 two hundred feet broad and a mile long, does not press 
 laterally with a weight in proportion to the mass of the 
 heaped up water. So weak an inclosure could hardly bear 
 a ton's weight. There is lateral force then only in that water 
 which runs over the dam, or escapes through the apertures. 
 That which is at rest can have no pressure ; for, if it had, 
 the weak barrier would be overthrown. 
 
 Suppose a stone weighing one hundred pounds, pressed 
 equally one very side by springs. With the pressure of 
 these springs it weighs just one hundre.d pounds as it did 
 without them ; for the action of one spring neutralizes the 
 pressure of the opposite spring, so that the "gravity" of 
 
MECHANICAL PHILOSOPHY". 155 
 
 the stone is not changed. We will take away the springs 
 and weigh this stone under water, which by theory presses 
 on it as did the springs, equally in every direction. It has 
 lost weight, therefore water does not press equally in all 
 directions on the stone. Nor does the water press down- 
 ward only ; for in this case the stone would weigh more in 
 water, " having to bear not only its own share of attractive 
 force, but the weight of all the strata (of water) over it." 
 
 How, then, can we ascertain the specific gravity of the 
 stone on both or either of the two laws of the gravitation of 
 fluids ? An equal pressure on all sides would be " dead 
 pressure," and the stone would weigh the same in water as 
 in air. A vertical pressure would increase its weight. 
 
 "We once heard two men disputing on this subject, one 
 affirming that a stone did weigh less in water, because he 
 had often tried it ; the other affirming that it could not 
 weigh less, " for you see," said he, " the stone is as much 
 drawn down by gravity in the water as out of it, and the 
 water cannot lift any, when there is more water over it 
 bearing clown than under it lifting up." 
 
 In fact, on either or all of the principles affirmed to ac- 
 count for the pressure, the change in the gravity of the 
 stone cannot be explained. It is true that the stone dis- 
 places a quantity of water equal to its bulk, but this fact 
 neither increases nor diminishes the force with which the 
 earth attracts it. What is the action of the surrounding 
 water ? How does it press on the stone ? Downward 
 only ? Surely not ; " fluids press equally in every direct- 
 ion." Equally on all sides? Then the "opposite dead 
 pressures" must entirely neutralize each other, and have 
 no effect whatever. The decreased weight of the stone can 
 be accounted for only on some new principle. 
 
156 OUTLINES OF A SYSTEM OF 
 
 We will bring the pressure of water to an infallible test, 
 that of our sense of touch, our honest perceptions which 
 favor no theory whatever. Immerse the hand in water ; 
 in the act of immersion pressure is felt, for the water is 
 moved by the introduction of the hand, but when it is at 
 rest in the water not the least pressure is experienced. 
 Place the hand near a small orifice from which water is 
 issuing, and pressure will be felt because there is a motion of 
 the water. Stop the orifice with the palm of the hand, and 
 there is no pressure ; for the water has ceased to flow. 
 
 We now pass to the consideration of that action of fluids 
 which is called the hydrostatic paradox, an increase of 
 pressure which is not in proportion to the force applied, but 
 is in proportion to the surface of the pressing fluid. A 
 multiplication of pressure is apparently produced, an 
 effect greater than the cause, by some supposed myste- 
 rious " principle of fluidity " applied force in some cases 
 increases its power according to the extent of the surface 
 against which it acts. 
 
 It is said that " the true laws of the equilibrium of fluids 
 were discovered by Archimedes, and rediscovered by Galileo 
 and Stevinus, the intermediate time having been occupied 
 by a vagueness and confusion of thought on physical sub- 
 jects." The doctrine is that, as a fluid is a body, the par- 
 ticles of which have a perfect intermobility, " therefore all 
 pressure exerted on one part is transferred to all other 
 parts." Stevinus deduced from this principle, that the 
 pressure on the bottom of a vessel filled with fluid, may be 
 greater than the whole weight of the fluid. And it is also 
 deduced, that the pressure may diverge, and may be multi- 
 plied in every direction. Pascal shows, in his Treatise on 
 the Equilibrium of Fluids, " that a fluid inclosed in a vessel 
 
MECHANICAL PHILOSOPHY. 157 
 
 necessarily presses equally in all directions by imagining 
 two pistons, or sliding plugs, applied at different parts, the 
 surface of one being a hundred times greater than the 
 other ; it is clear that the force of one man acting at the 
 first piston, will balance the force of one hundred men act- 
 ing at the other." And therefore he concludes that, " a 
 vessel full of water is a machine which will multiply force 
 to any degree we choose." 
 
 The apparent multiplication of pressure is indeed a diffi- 
 cult subject to grasp or comprehend. The explanations 
 given of the facts are far from being clear. This seems to 
 be admitted ; for, as Whewell remarks, " there is a difficulty 
 of holding fast this idea of fluidity. Even at this day, men 
 of great talents not unfamiliar with the subject, sometimes 
 admit in their reasonings an oversight or fallacy with regard 
 to this point. The importance of the idea when clearly 
 apprehended and securely held may be judged of from this, 
 that the whole science of hydrostatics, in its most modern 
 form, is only the development of this idea." But has all 
 " vagueness and confusion of thought " on this subject 
 passed away ? Is it now clearly understood how there can 
 be an equal pressure in every direction, and at the same 
 time the pressure be increased according to depth, and 
 again multiplied according to surface ? 
 
 The facts which are supposed to prove the multiplication 
 of pressure in fluids are, the elevation of a great weight by 
 a less weight of water, as in the hydrostatic -paradox, the 
 bursting of a full cask by the pressure of a very small quan- 
 tity of water poured into a long tube inserted in it, and 
 the floating of bodies in water of less weight than the mass 
 that is buoyed up. 
 
 The hydrostatic paradox, as it is called, may be exhibited 
 
 14 
 
158 OUTLINES OF A SYSTEM OF 
 
 in the following manner : Insert a long slender tube into a 
 cylinder with a movable piston ; pour water into the tube, 
 and the piston will be elevated by it ; if the tube holds only 
 a pound of water, and has an area only one hundredth part 
 as great as that of the piston, the pound of water poured 
 into the tube will elevate a hundred pounds placed on the 
 piston. The same action is shown in the Bramah press, by 
 which a great pressure is produced by gradual increments 
 of force, from water driven into a large cylinder by a small 
 forcing-pump. 
 
 The explanation which is usually given of these facts is, 
 " that as the pressure of the particles of fluid is equally dis- 
 tributed among themselves, so external force or pressure is 
 distributed in the same way." . . "In the hydrostatic press 
 an immense accumulation of force is brought to bear upon a 
 particular point, by pressure applied by a small column of 
 water reacting upon a large mass placed on the surface of 
 the piston." This explanation is hardly more than a recital 
 of the facts ; how or why the small column of water should 
 react with a force proportional to the surface against which 
 it is applied is not in the least explained. 
 
 The fact that the weight or pressure of one pound of water 
 may be made to produce a pressure equal to that of a hun- 
 dred or a thousand pounds, is in reality no more paradoxical 
 than that one pound on the long arm of a lever should 
 balance a greater weight on the short arm. Its action is 
 similar to that 'of other mechanical powers. There is no 
 increase or multiplication of the applied force. The descent 
 of every pound of water gives a spare force of descent suffi- 
 cient for the elevation of a pound weight. It will raise a 
 pound to the same height from which it fell, or one hundred 
 pounds T <Ju of the same height. 
 
MECHANICAL PHILOSOPHY. 159 
 
 But the force with which the weight is raised depends also 
 in part on the area of the surface of the piston. It is equiv- 
 alent to the force of a descending column with an area equal 
 to that of the piston. That is, the weight is raised with a 
 force as great as if the area of the descending column were 
 equal to its own, while the extent of the elevation is propor- 
 tional to the volume of the water which descends. The 
 extent of the area of the descending column does not change 
 the force of ascent of the column acted upon ; whether it is 
 of one inch or ten inches area, the effect produced is the 
 same. This constitutes the paradox, and it is this fact 
 which requires explanation. 
 
 We consider this fact as strong proof of the correctness 
 of our hypothesis regarding the nature of the molecular 
 action of fluids. Every volume of water has its molecular 
 force equally diffused through it. This force must of course 
 be the same in the cylinder as in the tube, because from 
 their connection they form one volume, while without the 
 connection the force would be different in the two columns, 
 on account of their differing depths. The molecular force due 
 to the greater depth of the long column is diffused through 
 the less depth of the water in the cylinder. And, being 
 equally diffused through this body of water, its action is of 
 course in proportion to the area of the water. The abnor- 
 mal molecular action of the shorter column comes from the 
 equal diffusion of the normal force of the longer column, and, 
 being abnormal in the shorter, it is converted into progress- 
 ive motion. Of course, the force of the progressive motion 
 acts upon the whole surface of the piston against which it 
 is applied. 
 
 We will endeavor further to explain this idea. In the 
 long slender tube the force of molecular action is in propor- 
 
160 OUTLINES OF A SYSTEM OF 
 
 tion to the depth of the water that it contains, but it equally 
 diffuses itself in the water of the cylinder ; this diffusion 
 gives an abnormal force for the depth in the cylinder, and 
 it is therefore changed into progressive motion, which is the 
 force for elevation. In other words, it is the height of the 
 column which determines the force of the pressure, and the 
 quantity of water falling which determines the extent of the 
 elevation. The reason that the force of elevation is in pro- 
 portion to the area of the surface of the water which lifts 
 the piston, is that the force of molecular action which is 
 ohanged into progressive motion is determined by this area. 
 The idea may be illustrated by comparing the molecular 
 force to spiral springs placed beneath the piston, the num- 
 ber of the springs being determined by the extent of the 
 surface against which they are placed ; of course, the larger 
 the surface, the greater the number of the springs in action 
 under it. Hence, " the force of one man may be made to 
 balance that of a hundred men ; " for the " reaction" is the 
 joint force of the one hundred and one men equally dis- 
 tributed. And hence it is, that " not only does the pressure 
 diverge, but is in all directions exactly equal, an equal 
 extent of the fluid being taken." 
 
 It has also been deduced from this idea, that, if any fluid 
 in a cylinder be pressed by a piston, the force which moves 
 the piston bears with the same power on every part of the 
 surface of the cylinder. For instance, if the area of the 
 piston is one foot, and it is acte.d upon with a force of one 
 hundred pounds, and the cylinder has an area of eight feet, 
 the one hundred pounds of pressure would be multiplied into 
 eight hundred pounds, to give the one hundred pounds press- 
 ure to each foot of the cylinder. But it is not so. The 
 one hundred pounds force is not in the least increased by 
 
MECHANICAL PHILOSOPHY. 161 
 
 the size of the cylinder, and is equally distributed over the 
 whole surface. The mistake has arisen from the fact, that, 
 if the cylinder is opened at any part, there will the whole 
 force concentrate itself; and because it can always be 
 brought to any one point, it has been supposed that it acts 
 with its whole force at every point at once. The molecular 
 force is converted into progressive motion only where it acts 
 against that which is movable ; it exerts itself where there 
 is room for motion. When confined, the force is equally 
 distributed throughout the containing vessel ; when suffered 
 to escape, its whole strength is transferred to the place 
 where there is room for motion. Tap the cylinder at any 
 part of its surface, and thence the fluid issues with the force 
 which theory assigns. Let the boiler of a steam-engine 
 burst, and at the rent will issue the force which theory has 
 made present at every part. The belief, however, may 
 have had a good practical result. The mechanic, on its 
 assumption, gives to his cylinders a strength in every part 
 capable of sustaining the whole pressure. The yielding of 
 any part of the containing vessel concentrates the force at 
 this point of comparative weakness, where the molecular 
 action of the fluid can change itself into progressive or con- 
 sentaneous motion. The force applied is neither increased 
 nor diminished by the extent of surface against which it 
 acts. It is an invariable quantity, and is equally distributed 
 throughout the containing vessel. 
 
 It has been a matter of great surprise to practical me- 
 chanics, that steam-boilers have continued to work safely, 
 when worn so thin that it appeared impossible that they 
 should bear the pressure which theory assigned. It was 
 recently mentioned to me by a friend, a gentleman of great 
 practical experience, that he had just examined the boilers 
 
 14* 
 
162 OUTLINES OF A SYSTEM OF 
 
 of a very powerful engine, which had been taken out for re- 
 pairs, and was exceedingly astonished to find them so worn, 
 so much corroded, that in some places he could indent them 
 with a slight pressure. 
 
 The force of molecular action, however, will not account 
 for the buoyancy or floating of bodies. The water around 
 them is of equable depth ; there is no confinement or unequal 
 pressure to produce an increased molecular action in any 
 one part of the volume of water. The molecular force exists 
 in its normal state as the counterpart or complement of the 
 rotative force. Nor is buoyancy produced by the gravitat- 
 ing power ; for, as before observed, bodies will float in water 
 of less weight than themselves. Place one cup within 
 another so that their surfaces will be nearly in contact ; 
 pour between them a little water, not one half as much 
 as the weight of the inner cup, and the cup will be lifted, 
 and will float. It is a perfectly established fact, that ships 
 do not require to float them a quantity of water equal in 
 weight to themselves. The water in repairing-docks, for 
 instance, may be far less in weight than the aggregate 
 weight of the floating ships. This fact is in direct opposi- 
 tion to the law of gravitation. It cannot be reconciled 
 with it ; for the greater weight should be drawn down, and 
 should displace the less weight. Even in the paradox the 
 gain of force is apparent only ; it is like the action of the 
 lever ; a larger weight is raised only in proportion to 
 the change of level of a smaller weight, the quantity of 
 motion being the same in both. By no mechanical contriv- 
 ance, whether it act on fluids or on solids, can there be a 
 positive gain of force. A pound cannot, by its pressure or 
 by its fall, sustain at or lift to its own level more than a 
 pound. 
 
MECHANICAL PHILOSOPHY. 163 
 
 If there is a gravitating power, it must act on the same 
 mass, at the same distance from the centre of attraction, 
 with uniform intensity. A cubic foot of water will invaria- 
 bly be acted upon with the same power. In fact, a measure 
 of water forms the standard of weight. Knowing therefore 
 the weight of a body to be lifted up, or to be held sus- 
 pended, the quantity of water, which would be drawn down 
 with sufficient force to bury up the mass immersed in it, 
 could be exactly calculated. The weight of the water 
 would measure its pressure, its effective force, its ele- 
 vating capacity. The extent of surface against which it 
 acted could not alter its efficacy. If, therefore, in the phe- 
 nomena of buoyancy, the heavier mass goes up or remains 
 up, and the lighter goes down or remains down, gravitation, 
 acting either directly or indirectly, cannot be the cause or 
 principle by which buoyancy is produced. 
 
 It is well known that the displacement by any floating 
 body, a ship, for instance, of a quantity of water equal 
 to its own weight, is the necessary condition of its buoyancy. 
 But the displacement of the water is not the cause of the 
 buoyancy. There is no virtue or efficacy in the place from 
 which the water is excluded. The pressure which gives 
 support must be outside ; it must be in the water around 
 the ship. If it is supported by the gravitation of the water, 
 by its pressure against the ship, the question is, on what 
 principle does the pressure act ? The extent of the pressure, 
 as we have seen, is not determined by the quantity of the 
 surrounding water. That may be more or less. Nor by 
 the depth of the space in water occupied by the floating 
 body ; for it may be wide and shoal, or narrow and deep, 
 and yet the quantity of water displaced be the same. Nor 
 is the pressure determined by the extent of surface exposed 
 
164 OUTLINES OF A SYSTEM OF 
 
 to it. Bodies of different surfaces may yet exclude the 
 same quantity of water. If the pressure, therefore, is deter- 
 mined neither by the quantity of water, nor by its depth, 
 nor by the extent of surface presented to it, gravitation is 
 not the cause of buoyancy. 
 
 The fact of buoyancy is, we think, susceptible of explana- 
 tion on our principles. We will suppose that a vessel con- 
 tains one hundred pounds of water, and that there floats in 
 it a block of wood weighing two hundred pounds. We will 
 mark the level of the water. Take out the wood and pour 
 in two hundred pounds of water, and the level remains as 
 before ; the water added, or rather two hundred pounds of 
 water, occupies the place of the wood. It acts and is acted 
 upon just as the wood acted and was acted upon. It is in 
 the place of the wood ; that which supported wood now 
 supports water. Enlarge the vessel, and pour in water 
 enough to make the level the same as before. The two hun- 
 dred pounds of water or of wood retain the same place with 
 a greater thickness of the strata at the sides. And reverse 
 it, narrow the vessel, and take out water, the wood floats 
 as before. The support neither of the water nor of the 
 wood was owing to the quantity of water around it. The 
 floating body then does not remain suspended from the 
 weight of the water in which it floats. There is no tendency 
 in the water to crowd it out of its place, nor any to hold it 
 in its place. A floating body has no tendency to sink or to 
 rise. It is not attracted downwards. It rests self-poised. 
 It preserves its level because it has the rotative force of its 
 level ; it floats because the rotative energy is equally diffused 
 through itself and the water. A ship has no weight on the 
 water ; she does not bear upon it ; the hand placed between 
 her and the water would not be in the least compressed. 
 
. 
 
 MECHANICAL PHILOSOPHY. 165 
 
 She is not attracted downward by gravitation, nor is the 
 water attracted upward against her. But if she descend 
 from her level, she has force of descent, as have all falling 
 bodies. She then bears upon the water, moving it by her 
 force of descent. The hand under her would then feel a 
 pressure. She floats as her weight of water would float. 
 
 Her motion, her rise and fall, is an oscillation which 
 corresponds to the oscillation of the waves. This vertical 
 motion is the transfer and re transfer of rotative force, her 
 mean level of rotation being still preserved. The wave, 
 rising by force robbed from the passing wind, transfers force 
 to the ship, which also rises ; this force expended in the su- 
 perior level, she pauses a moment, and then falls with accel- 
 erated force, till again met by the rising water, ever float- 
 ing as the body of water whose place she takes would float. 
 
 A picture is beautiful because it bears the impress of the 
 artist, because on the canvas has been laid the idea of 
 his mind, because by the drawing, coloring, and com- 
 bination, he declares the thought which engrossed him as 
 he sat at the easel. Thus nature is beautiful, when in ad- 
 dition to the mere outline, the form, the color, which the 
 eye takes in, the mind perceives also the characters, the 
 language w'hich declares the power and wisdom by which it 
 was constituted. 
 
 In this point of view how beautiful is a ship, borne along 
 on the wings of the wind ! She is not a mere combination 
 of wood and iron, of cordage and canvas, but she represents 
 and proclaims to us unseen force, the laws of the elements. 
 Hence the sailing of a ship becomes of absorbing interest ; 
 she is full of life, upborne by innate energy, as she bends to 
 the breeze, leaps joyously over the waves, or sternly defies 
 the power of the storm, 
 
166 OUTLINES OF A SYSTEM OF 
 
 "We referred, in the first part of this chapter, to the impos- 
 sibility of explaining what is called specific gravity, accord- 
 ing to the theory of the gravitation of fluids. The weight 
 of any mass of matter is supposed to measure exactly the 
 degree of attraction which the earth exercises upon it. 
 Why should the attracting force be lessened when the body 
 is placed in water? If an immersed stone were pressed 
 down by the water, its weight would be increased by the 
 immersion ; or, if the fluid pressed upon it equally in every 
 direction, its weight would remain the same as before. If 
 the pressure upon it were upward only, its loss of weight 
 might be accounted for. We explain the loss of weight of 
 a body immersed in water in the following manner : The 
 force which gives certain degree of motion to a body is mea- 
 surable by the quantity of matter that the moving body con- 
 tains, each atom receiving its due proportion. It follows 
 that the force required for any determinate degree of velo- 
 city depends, not on the volume of the body, but on its 
 density. The force required to move any body, therefore, 
 is in proportion to the quantity of matter which it contains, 
 not to its bulk, to its atomic structure, not to the space 
 that it occupies. The force needed for the motion of a body 
 in any direction being ascertained, the quantity of matter 
 in the body relative to the space that it occupies can also 
 be ascertained. 
 
 The force of rotation in bodies at the same level being in 
 direct proportion to the quantity of matter which they contain, 
 all bodies, large or small, dense or porous, in falling having 
 spare force proportioned to their quantity of matter, should 
 move downward with equal velocity without reference to 
 their bulk in relation to density. This is the case with 
 bodies falling in a vacuum ; a feather falls as quickly as a 
 
MECHANICAL PHILOSOPHY. 167 
 
 bullet. But in bodies falling through the atmosphere, the 
 greater the bulk relative to density, the less is the compar- 
 ative velocity, and in falling through water the retardation 
 of velocity is greatly increased. These results are usually 
 thus expressed : " The greater the bulk of the body com- 
 pared with the matter it contains, the more the air or water 
 resists the fall, and thereby decreases the velocity." Throw 
 away the consideration of velocity which is an effect, and 
 the statement is more simple. In a vacuum, the force of 
 descent relative to the matter is the same in all bodies, large 
 or small, light or heavy ; in the atmosphere a part of the 
 force derived from change of level is transferred to the air, 
 and there remains less force for descent ; in the water a 
 still greater part is transferred, and still less force remains 
 for descent. The force transferred to the air is exactly that 
 degree which is required to move a volume of air of the bulk of 
 the moving body, through the same extent of space, and with 
 the same velocity as that of the falling body. So the force 
 transferred to the water is that which is requisite to move 
 an equal bojly of water through the space described by the 
 fall, and with the velocity of the fall. In the descent of a 
 body, therefore, through air or through water, it moves, in 
 opening its path, a volume of the medium through which it 
 passes, of its own bulk, and with its own speed. Its loss of 
 force therefore measures the weight of its own bulk of the 
 fluid through which it passes. The water or air moved 
 may be moved upward, downward, or sideways ; but the 
 imparted force is exactly of that intensity, which would have 
 raised a volume of air or water of its own bulk as high as 
 the level from which the falling body descended. Hence 
 the retardation of the fall measures the weight or density of 
 the medium, and conversely the density of a stone is ascer- 
 
168 OUTLINES OF A SYSTEM OF 
 
 tained by being weighed in water. This is an unvarying 
 principle. The seeming discrepancy in the fact that the 
 fall of bodies of great extension of surface as compared with 
 their density is of less velocity, as in the case of the para- 
 chute, is because a mass of air must necessarily fall with 
 it, as if the air and parachute constituted one falling body. 
 If a mass of wood falls in a vacuum, its motion downward 
 is with all the force derived from its change of level. If in 
 air, it will fall, though with less force ; for the force derived 
 from its descent is sufficient to give it its own motion, and 
 to raise a quantity of air equal to its own volume. In water, 
 however, it cannot fall, for the force that would be acquired 
 by its descent to a lower level, is not sufficient to move a 
 quantity of water of its own bulk. In the space occupied 
 by the wood, the quantity of matter is less than it would be 
 in the same space if filled with water. The force of the de- 
 scent of the wood is in proportion to its own density, to its 
 own quantity of matter. In order to descend, it must open 
 its path. It must transfer enough of its force to move out 
 of the way the surrounding water, not a quantity at once 
 equal to its own volume, but a quantity proportional to its 
 degree of descent. If the water of equal bulk contains 
 more matter, the spare force of the descent of the wood is 
 not sufficient for any degree of the elevation of water ; of 
 course, there can be no descent of the wood. It can only 
 float. Buoyancy depends, therefore, on inferior density 
 compared with the medium in which it is placed, not on the 
 quantity of the medium. If a body placed in water contains 
 more matter than the same volume of water, it falls or 
 sinks. If of equal density with the water, it floats in it at any 
 distance from its surface. The case is the same in air, or 
 in any other medium. By weighing a body first in a vacuum, 
 
MECHANICAL PHILOSOPHY. 169 
 
 and afterwards in air. its comparative density can be ascer- 
 tained. In the floating of a ship, partly in the air, partly 
 in the water, her density is measured by both, that is, her 
 degree of specific weight gives her place between the two 
 elements. Lighter than her bulk of water, heavier than her 
 bulk of air, she neither sinks nor rises, but remains sus- 
 pended at the junction, at the meeting surfaces, of the ocean 
 and of the atmosphere. 
 
 It will be seen that this explanation is somewhat similar 
 to that which is usually given. Those who believe in ter- 
 restrial attraction do not think that a stone is less attracted 
 when in water ; they attribute its loss of weight to its dis- 
 placement of water, because the loss is measured by the 
 weight of the quantity of water that would fill the space 
 occupied by the stone. But it is not what a stone excludes, 
 but the quantity of matter which it contains, which deter- 
 mines its weight, and its atoms remain the same whether it 
 is weighed in water or in air. An explanation, therefore, 
 based upon the theory of gravitation, cannot refer to the 
 quantity of water excluded by the stone, for the force with 
 which it is attracted is not lessened thereby. The stone and 
 all that it contains, that is, all that is interior to the medium, 
 is unchanged by the medium. Under the theory of gravi- 
 tation, there can be no cause for the loss of weight except 
 the action of that which is exterior to the stone ; in other 
 words, the degree and kind of the pressure upon it. 
 
 But outside there is no conceivable action of the water 
 induced by its gravity, that can possibly result in a loss of 
 weight of the stone equal to the weight of excluded water. 
 Gravitation, we repeat the idea, pressing the water down- 
 ward upon the stone, will not give the result ; gravitation, 
 pressing the water against the stone equally in every direc- 
 
 15 
 
170 OUTLINES OF A SYSTEM OF 
 
 tion, will not 'give it ; nor will a current of water moving 
 from above to beneath the stone, for under the law of grav- 
 itation it does not require a force equal to the weight of a 
 given quantity of water to move this water when under 
 water. For a reason of the loss of weight, therefore, all, 
 whatever be the theory, are compelled to go from the press- 
 ure upon it to the body itself ; from the action of external 
 force, to the force pertaining to the stone ; from the theory 
 of gravitation, of external attraction, to the force of motion. 
 Our theory, which gives place and position to matter accord- 
 ing to its degree of rotative force, does not require to be 
 changed. 
 
 There is indeed no reason to be given under the theory 
 of gravitation, why a stone should lose in weight the weight 
 of water which would occupy its place. There is nothing in 
 gravitation by which it can so modify its action on the sur- 
 rounding water, as to make it press upon the stone in exact 
 proportion to its solid contents. This theory, therefore, 
 cannot explain specific gravity by the attraction of the stone, 
 or by the attraction of the medium ; nor by any possible 
 combination of the two. Gravitation cannot attract the 
 stone more or less, or the water more or less, from the fact 
 that the stone and water are in contact. Nor can the 
 result be modified except by mutual pressure, and we have 
 seen that the kind of pressure which gravitation induces is 
 totally inadequate to explain the phenomena. 
 
 On the other hand, do not we present an intelligible and 
 distinct explanation ? We consider force as having an 
 actual existence. In the case of a body falling through 
 water, we show the source of the power by which it moves, 
 the force of descent from a higher level, and we trace out 
 the division of this force in action. There is so much less 
 
MECHANICAL PHILOSOPHY. 171 
 
 in action upon the stone, as is transmitted for the motion 
 of the water necessary for the relative change of place. 
 Specific gravity weighs this force. Weight is the force of 
 motion. It is not an incomprehensible abstraction ; it is 
 not an instinct or tendency of matter to approach matter. 
 There is no weight without motion, and the cause of motion 
 is the force present in the moving body. Has not philosophy 
 erred in referring to other matter as the cause of all motion 
 in matter, instead of looking where the motion is for the 
 force which produces it ? Why may it not be supposed 
 that matter has power to move itself, as well as that it can 
 induce motion in other matter ? 
 
 As we have before said, water is elevated by receiving a 
 share of the stone's force of descent ; in other words, water 
 goes up because the stone goes down. Often, however, 
 matter descends because other matter ascends. We take 
 a balloon as an instance of this converse action. It is sup- 
 posed that a balloon goes up from the superior weight of a 
 volume of air of its own size, that it is crowded or pressed 
 out of its place by a fall of air into its place. Can this 
 be so? 
 
 Air either presses downward upon the balloon, or equally 
 upon it in every direction. As we have before said, neither 
 nor both of these pressures could produce elevation. The 
 current of air from above downward is not established until 
 the balloon has commenced its rise ; this current is there- 
 fore a result of the motion, not its cause. As water is lifted 
 by the fall of a stone into it, so air is moved downward by 
 the ascent of a balloon. It is the peculiarity of construction 
 or of element in the stone which enables it to fall in relation 
 to water ; it is the construction or elementary constitution of 
 the hydrogen of the balloon which causes its rise in relation 
 to the atmosphere. 
 
172 OUTLINES OF A SYSTEM OF 
 
 This idea we will illustrate by supposing a balloon held 
 down by a cord, and a dense body of the same size and form 
 held up by a cord, each producing the same tension of the 
 cords which restrain their motion. They are at rest. The 
 air presses on both in the same manner and with the same 
 force. The " tendency " of one to go up, and of the other 
 to go down, comes not from the atmosphere ; for its pressure, 
 being on bodies of the same form and size, is of course the 
 same on both. By drawing each of them aside, by giving 
 them an impulse, they will swerve to and fro as does a pen- 
 dulum. The air does not aid this movement, but retards it ; 
 for both the swinging bodies lose a part of their force of 
 motion by the " resistance " of the medium in which they 
 oscillate. Does gravity cause this converse oscillation, by 
 depressing one giving it force for elevation, by elevating the 
 other giving it force of depression ? When the oscillation 
 is suspended, if the cords which confine them are cut, one 
 will commence its rise, the other its fall, before a particle of 
 air has moved in relation to either. If we suppose two 
 equal receptacles, one filled with hydrogen so that it will 
 rise, the other with a gas heavier than the atmosphere so 
 that it will fall, the external air bearing on each with the 
 same pressure because they are of equal size and similar 
 shape, we cannot avoid the conclusion that the cause of the 
 rise of the one and the fall of the other depends not on the 
 surrounding medium, but on a positive difference in the 
 structure or character of the inclosed gases. 
 
 It is impossible to suppose that gravitation attracts the 
 one and repels the other, or that it modifies the pressure of 
 the air around the one to favor its ascent, and around the 
 other to favor its descent. The interchange of force from 
 the medium to the moving body, or from the moving body 
 
MECHANICAL PHILOSOPHY. 173 
 
 to the medium, is a result of motion ; it is not the impelling 
 cause. 
 
 The cause of all motion is the presence of force in the 
 moving body. The degree of rotative force determines the 
 level of rotation. For instance, hydrogen at its formation, 
 at the commencement of its separate existence, possesses an 
 intense molecular force. If unconfined this force changes 
 into progressive motion, and it rises, exhausting its atomic 
 intensity in rotation at the higher level. Its power of ele- 
 vation, and the height of its rise, depend therefore on the 
 degree of the present force. 
 
 But the question returns, what causes some bodies to 
 ascend and others to descend relatively to the medium in 
 which they move ? Why does hydrogen change its force 
 of molecular action into progressive motion at the higher 
 level ? Why does the stone give up a part of its rotative 
 force and descend ? In other words, what is the principle 
 which governs the degree of rotative force, which bodies 
 left free to take their own position will retain ? 
 
 We have before noticed the fact that cohesion and chemi- 
 cal affinity both depend upon sympathy of molecular action, 
 on the equality of the diffusion of the present force. It is 
 this which forms all combinations, and determines the sepa- 
 rate existence of masses and of volumes. And as the force 
 present in each atom determines its position in relation to 
 other atoms, in their combination forming masses, the same 
 principle determines also the relative position of the masses. 
 
 Molecular action is the counterpart of progressive motion ; 
 there is a- normal ratio between them. The degree of rota- 
 tive force that any mass or volume can retain if free to 
 change its position, depends upon its capacity for molecular 
 action. This capacity depends upon atomic structure, and 
 
174 OUTLINES OF A SYSTEM OF 
 
 atomic structure determines level. The fall or rise of 
 bodies relatively to each other, is determined therefore by 
 the comparative density of the moving masses. One law 
 not only governs combination, but also governs the level of 
 rotation. 
 
 Comparative density, the quantity of matter relatively 
 to the space occupied, in other words, capacity for the 
 motion of its atoms, determines whether a body rises, or falls, 
 or remains suspended, in any medium. And as all terres- 
 trial bodies move in some medium, or move relatively to 
 other matter, it is the distance between the particles of a 
 body, its atomic structure, which causes it to rise or to 
 fall, or which gives it a relatively permanent position. The 
 force of rotation belonging to position is not always the nor- 
 mal force of the structure of the body. If, therefore, there 
 is space for motion, it is moved upward or downward until 
 position conforms the rotative force to the normal degree of 
 molecular force, which is its counterpart. The result is the 
 formation of currents of revolving matter, in which there is 
 an equality of the diffusion of force in relation to space, as 
 well as in relation to density. The result is, the sympa- 
 thetic motion of every atom composing the world, a reg- 
 ular increase of motion from its centre to its outermost 
 circle. 
 
 To unfold this principle as far as it appears to us dis- 
 tinctly conceived, would require a greater space than can 
 be given in this outline. It would be out of place also in 
 a treatise designed to present only the very first principles 
 of a theory. We confine ourselves therefore to the thoughts 
 already suggested. A body falls because it is not sur- 
 rounded by that medium for which its atomic structure fits 
 it ; it is not in that stream of revolving matter in which 
 
MECHANICAL PHILOSOPHY. 175 
 
 force is normally diffused. It falls when the force gained 
 by descent is not only sufficient for its downward motion, 
 but also sufficient to give the corresponding elevation to its 
 volume of the matter by which it is surrounded. A body 
 rises under analogous conditions, when it has force not 
 only for its own ascent to a higher level, but enough to move 
 from its path its own volume of the surrounding matter. 
 A body rises or falls according to its present force, accord- 
 ing to its atomic structure or capacity for molecular action. 
 
 The equilibrium of force, the normal motion of matter, is 
 preserved by the resolution of the molecular into greater 
 progressive motion, at a superior altitude, or by the decrease 
 of rotative force by the descent of a body. The force 
 pertaining to the atoms and that pertaining to the mass are 
 thus brought into conformity, whatever may be the structure 
 of the mass ; the great result is harmony of motion, the 
 equality of the diffusion of force. 
 
 The rise and fall of bodies, therefore, is but an inter- 
 change of place between equal volumes of matter. And, 
 while the cause of the motion of a body is within itself, as 
 to the velocity and direction of its motion, it depends upon 
 the medium through which it moves. Matter influences the 
 motion of other matter only by an interchange of force, 
 by the transmission of motive energy from one body to 
 another. It is force which 
 
 " Sweeps through the dull, dense world, compelling there 
 All new successions to the forms they wear." 
 
 Thus is the place and position of all things determined, 
 not by the " appetite of matter" for matter, not by the 
 desire of one fragment of the world for the presence of 
 another fragment, not by mutual attraction, not by a 
 
176 OUTLINES OF A SYSTEM OF 
 
 blind instinct of consolidation, kept at times in abeyance by 
 an equally blind instinct of repulsion. It is by the diffusion 
 of force, giving the position of every atom, that the order of 
 the universe is maintained. Change is as normal as per- 
 manence, fluctuation as much a phase of perfection as 
 stability itself. A solitary rain-drop gives us a glimpse of 
 the law, which in its action clothes the earth with verdure ; 
 the sudden shooting of a minute crystal into perfect sym- 
 metry discloses the power which gives form and cohesion 
 to the world. 
 
 This view carries us again to the thought which we have 
 before attempted to elucidate, to our idea of the unity of 
 force, to the oneness of that energy, which under many 
 manifestations constitutes the " Life of the Universe." 
 We hear it in the rustling of the forest leaves, in the roar 
 of the ocean, in the thunder of the storm ; we see it in 
 the aurora's arch, in the volcano's blaze, in the lightning's 
 flash ; we trace it by the oscillations of the barometer, by 
 the tremblings of the magnetic needle, by the action of the 
 voltaic pile ; we witness the full majesty of its action in 
 the motions of the spheres. 
 
 This thought, which resolves the powers which move all 
 things above and around us into one and the same force, 
 ever circulating, ever inducing perfection, never subsiding 
 into rest, is not a mere poetical idea, a dream of the 
 imagination. The fact of the unity of force, the identity 
 of its nature under whatever form it may present itself, 
 is proved by the most accurate experiments, by the severest 
 tests of philosophy. Fill a metallic plate with a crystalliz- 
 ing solution, place a horseshoe magnet under it, crystalliza- 
 tion ensues immediately, and the line of crystals formed 
 writes down the direction of the current of magnetic force. 
 
MECHANICAL PHILOSOPHY. 177 
 
 Cohesion, then, is but one phase of force, symmetry of 
 form one of the results of its action. A rain-drop falls be- 
 fore us. We know from the experiments of Farraday the 
 exact amount of force which formed it from its constituent 
 gases, and by the abstraction of which it will be again 
 resolved into its elements. Further, we trace in its fall the 
 operation of the same force which gives its rotative and 
 revolving motion to the world. 
 
 For another illustration, we would recur to the fact that 
 metallic bars, when cooling under certain conditions, are 
 thrown into a state of vibration, and emit a musical note 
 like the sound of an eolian harp, and that the same note is 
 again heard from soft iron when becoming magnetized. 
 Thus the poetry of science is but the revelation of its highest 
 truths. Why should we continue to regard the world's 
 beautiful mystery with but one pervading idea, that of the 
 power of matter to draw other matter into contact with it ? 
 As well might we attempt to solve all the phenomena of 
 animal life by the attraction of the particles of the body for 
 one another, or all the phenomena of thought by bodily- 
 sensation, by atomic wisdom. 
 

 CHAPTER VIII. 
 
 " HE SUNG THE SECRET SEEDS OP NATURE'S FRAME ', 
 JlOW SEAS, AND EARTH, AND AIR, AND ACTIVE FLAME 
 FELL THROUGH THE MIGHTY VOID, AND IN THEIR FALL 
 WERE BLINDLY GATHERED IN THIS GOODLY BALL." 
 
 Dry den's Virgil. 
 
 A FULL belief in the attractive force of matter causes 
 every fact to be seen through this theory as a medium. 
 It therefore gives coloring to facts ; as it were, it corrects 
 observation ; it makes experiment conform to what it has 
 previously determined ought to be the result ; it asks, how 
 discrepancies can be explained, not, Can they be explained ? 
 
 How different the mental process in regard to a new 
 theory. The question at once changes its form. It is now, 
 Is it possible that this theory can be true in the very face 
 of this or that disagreement with observed facts ? In one 
 case, ingenuity exerts itself in accounting for discrepancies ; 
 in the other, in discovering them. 
 
 We will refer to one illustration of this idea, though it is 
 somewhat foreign to the immediate subject of the present 
 chapter. It is well known that the pendulum alters its rate 
 over different parts of the surface of the earth, in the same 
 parallels of latitude. In different mines, too, it varies* at 
 the same depth. Of course, it might be inferred that the 
 force of gravitation changes in intensity. But, according 
 to theory, gravitation is invariable in relation to the same 
 
MECHANICAL PHILOSOPHY. 179 
 
 quantity of matter. Thence it follows, if there be less 
 attraction at any one point, that there are caverns and hol- 
 lows in the earth ; if there be more, the density of the 
 rocks near the surface is far beyond the mean density of 
 the earth ; or there are " deflecting causes concealed be- 
 neath the surface of the soil." Why the less density of the 
 ocean does not invariably change the rate of the pendulum 
 has not yet been declared. The Shechallien mountain in 
 Scotland deflects a plummet from the vertical direction, 
 and from this swerving the mean density of the earth has 
 been calculated. Other mountains cause little or no pertur- 
 bation of the attractive force ; they are therefore but hollow 
 cones, though they may have miles of height and miles of 
 base, they are mere shells, the thin walls of extinct vol- 
 canoes ! Volcanic islands, on the other hand, generally 
 show " an augmented intensity of the attraction of gravita- 
 tion ; " where there is an exception, it is traced to the influ- 
 ence of some high land on a neighboring coast. Thus a 
 theoretic uniformity is preserved, whatever may be the 
 statement made by facts. The mountain which swerves the 
 plummet is proof of the universal law of the attraction of 
 matter ; that which does not offers no disproof, leads to 
 no doubt of the general principle. It is well that it is so. 
 Theories thus establish order, when without them there 
 would be confusion. It is better to obey a provisional gov- 
 ernment, though it be not destined to perpetuity, than to be 
 entirely without law. Theories are but steps in progress. 
 How painful the thought that any present knowledge is the 
 highest that can be attained ; that any theory is the widest 
 reach of the intellect ; that in the future there are in store 
 for us no further interpretations of the wisdom of God as 
 written upon his works ! 
 
180 OUTLINES OF A SYSTEM OF 
 
 We return to the examination of the theory of the gravi- 
 tation of fluids. If a tumbler is filled with water, a piece 
 of paper pressed over its mouth, and the glass then in- 
 verted, the water, instead of falling from it, will remain sus- 
 pended. The slight adhesion of the paper is sufficient to 
 overcome the whole force of the attraction of the earth upon 
 the water. This is explained by the pressure of the air 
 induced by gravitation, which is supposed to act upward 
 against the paper. 
 
 But, according to the principles of the gravitation of fluids, 
 this effect could be produced only when there is no air left 
 in the tumbler with the water. It has been stated that, if 
 the smallest quantity of air remained, its pressure above the 
 water would neutralize the pressure of the external air, and 
 the water would fall. But such is not the fact. Let the 
 glass be one half, one quarter, one eighth full of water, and 
 then inverted as before, the water will remain suspended 
 with air over as well as below it. We have often tried this 
 experiment, and called others to witness the fact, that water 
 suspended mid air, with the same pressure above as below, 
 refuses to obey the law of gravitation. 
 
 Fill a long tin tube with dry sand, and press on one end 
 a piece of thin paper slightly moistened ; let the upper end 
 be open so that the pressure of the air will act both upwards 
 and downwards upon the sand, and thus neutralize itself as in 
 the former case. The sand will not overcome the friction 
 of the sides of the tube and the adhesion of the paper, and 
 will remain suspended, say two pounds of it, against the 
 attraction of gravitation. 
 
 Here is a case precisely analogous to that of the water 
 suspended in the tumbler. How is it explained ? " Single 
 grains of sand placed on a flat surface do not begin to roll, 
 
MECHANICAL PHILOSOPHY. 181 
 
 until the heap is inclined between 30 and 40, and this is 
 the angle at which pressure is exerted, when this motion is 
 resisted ; and the weight of a pyramid, whose sides are in- 
 clined at this angle is supported at the base alone, whatever 
 may be the height of the column confined above it," there- 
 fore, " the paper supports the sand, though it adheres very 
 slightly; " or, to express the conclusion in other words, the 
 force of the adhesion of the paper to the edges of the tube, 
 an adhesion, which a very slight force would overcome, can 
 bear up against the gravitation of several pounds. Why 
 speak of the angle at which sand rolls ? It is not necessary 
 for the earth to roll the sand in order to bring it down. 
 
 Here are several pounds of sand supported by the friction 
 of the tube, and the adhesion of the damp paper against the 
 action of gravity. This is a plain statement of the fact, and 
 the explanation should be intelligible, without the mystifica- 
 tion of the angles of a pile of sand, or of the rolling of sand ; 
 for the fact has no reference to rolling, nor to the stability 
 of a heap of sand firmly supported at its base. 
 
 The reason for the suspension both of the sand and of the 
 water is the same. It is not the pressure of the atmosphere ; 
 for this pressure is neutralized by being above as well as 
 below the suspended matter. The force of a falling body is 
 gained only by its descent. Relatively to the containing 
 vessel, neither the sand nor water has descended. It has 
 acquired no force, and it is not attracted downwards. The 
 glass, raised or depressed by the hand, receives from it the 
 degree of force for its different levels. The water and the 
 glass are as one mass for rotation, the force being equally 
 diffused through them. 
 
 The reason that the paper makes the glass and its con- 
 tents as one mass is obvious. It arrests the beginning of the 
 
 16 
 
182 OUTLINES OF A SYSTEM OF 
 
 process of descent. It permits no particle to acquire force 
 of descent. It could not withstand an attraction of gravity ; 
 but it prevents any fall by which the contents of the glass 
 can acquire force for the downward motion. Take away the 
 paper, and the sand or water will issue, the surface sink- 
 ing as stratum by stratum the descending matter makes 
 room for the upper strata to descend. Each stratum for 
 itself gains force of descent by its- descent ; each stratum 
 quietly waits for its turn. The paper prevents the com- 
 mencement of this process, and, until it begins, the tube 
 and its contents rotate at any level as one mass, with the 
 rotary force equally diffused through it. 
 
 We have thus presented water remaining suspended with 
 a volume of air above it of the same elasticity as that below 
 it, and sand supported in the same manner with the weight 
 of the whole atmosphere pressing upon it above as well as 
 below. We pass from these to other proofs of the want of 
 attractive power in the earth. 
 
 If water be pressed upon by a piston, as in a common 
 forcing-pump, with a force of fifty pounds, this pressure will 
 show itself in the strength of the issuing jet. Now take 
 away the piston, and replace it with what under the law of 
 gravitation would be an exact equivalent, fifty pounds of 
 water. The pressure of this water, if it were attracted 
 downward by the earth, would be equal to fifty pounds of 
 external force. But the issuing jet is not increased in 
 nearly the same ratio as when pressure was applied by the 
 piston. The fact is, that the added water has no pressure, 
 and the increase in the force of the jet by its addition, re- 
 sults only from the lengthened column of water, which gives 
 increased force of descent. The increased force of the jet 
 bears an exact mathematical relation to the increased alti- 
 
MECHANICAL PHILOSOPHY. 183 
 
 tude. Before the addition, the velocity of the jet at the ori- 
 fice was the square root of half the altitude of the water. 
 The addition of the fifty pounds gives a jet, the velocity of 
 which is the square root of half the new altitude. In other 
 words, the force of the jet is the force of rotation unused by 
 the water which has descended in the cylinder, and to get 
 this measure, the mean descent, or half the altitude of the 
 descending column is the element of calculation. The water 
 at rest is not attracted, does not bear upon the water 
 below it. The addition of the fifty pounds alters the jet, 
 only by increasing the elevation from which the water falls. 
 
 But there is another fact relating to the flow of water, 
 which is beautifully illustrative of the views we present. A 
 jet of water, issuing from the orifice of a containing vessel, 
 contracts at a short distance from the orifice. This is 
 technically called the vena contracta. The velocity of the 
 issuing jet at this contracted point is the square root of the 
 whole elevation of the water, while, as before stated, the 
 velocity of the jet at the issuing orifice in the side of the 
 vessel is only the square root of half the elevation. 
 
 We believe that the increased velocity of issuing water at 
 the vena contracta has never been satisfactorily accounted 
 for, and it is admitted that the whole subject of the motion 
 of fluids is still imperfectly understood. We will briefly 
 sketch the history of speculation on this subject, taking our 
 account chiefly from the History of the Inductive Sciences, 
 to which we have so often recurred when we wished for a 
 clear statement of philosophical opinion. 
 
 Castelli was the first to assert that the velocity of efflux 
 depended on the depth of the orifice below the surface. 
 Torricelli also stated in 1643, as the result of his experi- 
 ments, that the fluid would spout nearly to the height of the 
 
184 OUTLINES OF A SYSTEM OF 
 
 surface, and 'inferred that the full velocity is that which a 
 body would have in falling through the depth, and that the 
 velocity is consequently proportional to the depth. 
 
 Newton, in his Principia, treated the subject theoretically, 
 that is, according to the theory of gravitation ; but " La 
 Grange says that this is the least satisfactory portion of that 
 great work." Newton made experiments different from 
 those of Torricelli ; he measured the quantity instead of 
 the velocity of the flow. The velocity inferred from the 
 quantity is only that due to half the depth of the water. 
 
 Newton explained the difference by observing the con- 
 traction which the jet of water undergoes just after it leaves 
 the orifice. At the orifice the velocity is that due to half 
 the height, at the vena contracta it is that due to the whole 
 height. The former velocity regulates the quantity of the 
 discharge ; the latter, the force of the jet. 
 
 " In the second edition of the Principia, Newton attacked 
 the problem in a manner altogether different from his former 
 one. He there assumes that where a round vessel contain- 
 ing fluid has an orifice at its bottom, the descending fluid 
 may be conceived to be a conoidal mass, which has its base 
 at the surface of the fluid, and its narrow end at the orifice. 
 This portion of the fluid he calls the cataract, and supposes 
 that while this part descends, the surrounding parts remain 
 immovable, as if they were frozen ; in this way he finds a 
 result agreeing with Torricelli' s experiments on the velocity 
 of efflux." 
 
 " We must allow that the assumptions by which this result 
 is obtained," continues Whewell, " are somewhat arbitrary ; 
 and those which Newton introduces in attempting to connect 
 the problem of issuing fluids with that of the resistance of a 
 body moving in a fluid are no less so. Even up to this 
 
MECHANICAL PHILOSOPHY. 185 
 
 time mathematicians have not been able to reduce problems 
 concerning the motion of fluids to exact calculation, without 
 
 introducing some steps of this arbitrary kind Hence 
 
 the science of the motion of fluids, unlike all the other 
 primary departments of mechanics, is a subject on which 
 we still need experiments to point out the fundamental 
 principles." 
 
 We would ask the question, may it not be found that 
 the theories connected with this subject require an examin- 
 ation ? The facts will not change their character ; the jet 
 of water will ever continue to bear the same relation to the 
 depth of the column as in the days of Torricelli and Newton. 
 The quantity of water flowing out, as also its velocity at the 
 orifice, will be that due to a fall from one half the height of 
 the column ; its velocity at the vena contracta, and the 
 height of its rise, will retain their relation to the whole 
 depth of the column, that is, at the orifice the velocity 
 will ever be the square root of the half altitude, at the vena 
 contracta, the square root of the entire altitude. 
 
 If water in the containing vessel were the subject of ter- 
 restrial attraction, the force of the jet at the issuing orifice 
 would be determined by the whole weight of the water. As 
 we have seen, this is not the case. Or if the attraction 
 acted only on a column of the same area as the opening, the 
 force of the jet would be determined by the whole height of 
 the column. But, as we have before said, it is found on 
 experiment, that the force of the jet at the orifice and the 
 quantity of water issuing, is that which is due to one half the 
 height only. On our principles, the force of the jet, being 
 the force freed by descent, could be related only to one half 
 the height ; for the water at the orifice would have no force 
 of descent within the vessel, while the water at the surface 
 
 16* 
 
186 OUTLINES OF A SYSTEM OF 
 
 would have the force due to the whole distance from the top 
 to the aperture. Of course, the force of the jet would be 
 the mean force of the column, or the force of the descent 
 from one half the height. This appears almost perfect proof 
 that it is force from descent, and not an attractive force, 
 which gives the velocity of the jet, and determines the 
 quantity of issuing water. If gravitation brought down the 
 water, the whole of the column being equally attracted, the 
 force of the jet would be that due to the whole height. 
 
 As the force of the jet, therefore, is determined, not by 
 the quantity, but by the height of the water in the contain- 
 ing vessel, it is force of descent only which governs the 
 intensity of the flow. There can be no difference of opinion 
 thus far. Action on the jet is confined to the water which is 
 in motion. In fact, the impelling power is usually stated to 
 be the force of descent induced by the action of gravitation. 
 
 But this force of descent does not account for the in- 
 creased velocity at the vena contracta. It is in its full 
 intensity at the moment the water issues from the orifice. 
 All the power produced by the change of level has accumu- 
 lated at the aperture, and after the water has issued it can 
 receive no farther increment of force from descent within. 
 Its increase of velocity after it has left the vessel, is not 
 therefore from the force of descent. Nor is the motion ac- 
 celerated because the jet is contracted ; as the quantity of 
 water remains the same, the size of the stream depends on 
 the velocity of its passage. The contraction is occasioned 
 by the more rapid flow of the particles of water ; it does 
 not cause the rapidity. The jet occupies less space because 
 it is accelerated ; if it were retarded, it would increase in 
 circumference. Most unquestionably, therefore, the water 
 after leaving the vessel, after its possession of the full im- 
 
MECHANICAL PHILOSOPHY. 1ST 
 
 pulse from the fall within, is acted upon by a new impelling 
 power. The jet is doubled in velocity, and by a cause 
 which commences its action after the issue of the water. 
 The increase of velocity at the vena contracta cannot be 
 caused by the force of descent, whether this force of de- 
 scent comes from gravitation, or from change of the level of 
 rotation. 
 
 But the increase is measured by the depth of the water 
 from which the jet proceeds. There is then a difference in 
 the state or condition of water according to its depth. This 
 difference is in the degree of molecular action. As we have 
 before observed, we believe that the force of rotation de- 
 creases from the surface of a fluid downward, and that mole- 
 cular force increases proportionally in the same direction, 
 that the one is the complement of the other, giving to the 
 whole volume of the fluid an equal diffusion of force. The 
 proofs of this theory seem to multiply as we proceed. And 
 the increase of the velocity of the jet at the vena contracta, 
 not only shows the existence of this molecular force, but 
 gives us the measure of its intensity, and its intensity thus 
 determined presents it as the counterpart of the force gained 
 by descent. 
 
 At the orifice we have a force of flow which is due only 
 to the mean descent of the column of water ; at the vena 
 contracta we have an additional force exactly equivalent to 
 it, so that at this point the force is equal to that which would 
 be disengaged by descent from the whole height of the 
 column. The two forces are therefore the exact counter- 
 parts of each other. If the stratum of water nearest the 
 orifice has no force of descent, it is compensated by a 
 greater molecular force ; if the stratum at the upper surface 
 has less molecular energy, it is compensated by its greater 
 
188 OUTLINES OF A SYSTEM OF 
 
 rotary force. % The velocity of the jet at the orifice is the 
 result of only one force ; at the vena contracta it is that of 
 the sum of the two forces. At the orifice there is only the 
 force of descent ; at the vena contracta the force of the mo- 
 lecular action is added to it. The change of level throws 
 the force of descent into action on the jet ; the escape from 
 the depth changes the molecular force of that depth into 
 progressive motion at a short distance from the orifice. 
 
 It is also found that more water discharges itself from a 
 reservoir through a short pipe, than through a naked aper- 
 ture of the same diameter as the pipe. This fact has been 
 explained by the supposition, that " the issuing particles 
 corning from all sides to escape, cross and impede each 
 other in rushing through a simple opening, as is proved by 
 the narrow neck which the jet exhibits a little beyond the 
 opening ; but in a tube this narrowing of the jet cannot 
 happen without leaving a vacuum around the part, and the 
 pressure of the atmosphere resisting the vacuum causes a 
 quicker flow." Surely the results of atmospheric pressure 
 induced by the attraction of gravitation are many and won- 
 derful ! Here we have an increased efflux of water by the 
 pressure of air against it ! 
 
 The contraction, as we have observed, is caused by the 
 increased velocity of the jet ; for of course from the more 
 rapid motion of the water, there is less of it at any one mo- 
 ment at any one point of its path. The effect of the short 
 tube is to prevent the full contraction, by the adhesion of the 
 water to its interior surface ; but, as this adhesion does not 
 overcome all the gain of velocity by the transfer of molecu- 
 lar into progressive motion, the force, instead of acting at a 
 distance from the aperture, diffuses itself and makes an 
 average velocity of all the water in the pipe. By friction 
 
MECHANICAL PHILOSOPHY. 189 
 
 the additional velocity is thrown back to the aperture, 
 increasing the speed of the fluid through it. To obtain the 
 greatest possible increase of flow, the tube should first nar- 
 row to the point where the vena contracta forms in the 
 natural jet ; this gives time for the transfer of atomic into 
 progressive motion ; then it should widen from this point so 
 that the water may spread itself with the increased flow. It 
 will be seen that the effect of this appliance, technically 
 the conical ajutage, is to make the velocity of the vena 
 contracta the same with that at the point of efflux, the 
 velocity at the opening. Increased velocity at the aperture 
 emits a greater quantity at any one time than would pass 
 with a less velocity. The greater the efflux, the greater the 
 force of descent, and the greater the addition to the flow 
 by the action of the molecular force. 
 
 It appears to us a clear explanation of the effect of 
 conical ajutages, to consider them as the means by which 
 the force that without them would act only away from the 
 opening, increasing the velocity at a distance from it, is 
 made to act at the opening where the greater velocity passes 
 through the aperture a greater quantity of water in a given 
 time. By the retardation of the flow of the water by the 
 friction of a pipe, the force of the flow is not annihilated. 
 It is still in being, and if its onward action be impeded, it is 
 thrown back toward the opening, giving passage to more 
 water from the reservoir. And with more water comes its 
 own force of propulsion, and of reflex influence. So the 
 gain in the flow is limited only by the quantity of molecular 
 action which the depth of the reservoir can supply, and 
 that is limited to what would be the force of descent if all 
 the issuing water fell from the upper surface of the reservoir. 
 
 By the theory of gravitation the efflux of water from the 
 
190 OUTLINES OF A SYSTEM OF 
 
 opening in the reservoir is represented as the effect of terres- 
 trial attraction, and yet there is an admitted impossibility of 
 giving by this theory any thing which approximates to a 
 clear explanation. Why, if the water in the reservoir is 
 attracted, and the result of this attraction is an equal press- 
 ure in every direction, does not the jet respond to this 
 pressure when it answers at once to the presence of any 
 external force so applied as to bear upon the particles of 
 the water in any direction ? If there can be clear proof of 
 any position whatever, there is this clear proof that gravita- 
 tion does not in the least degree press together the particles 
 of a fluid. 
 
 Why again is the issuing jet imputed to the force of 
 descent induced by gravitation, when it is so palpably evi- 
 dent that a part of the velocity of the jet comes after the 
 descent has exerted its full influence, and when the quantity 
 of water discharged is increased by an appliance which can- 
 not possibly be supposed to have the least effect in increas- 
 ing the force of descent ? And why impute the whole force 
 of the jet to a cause, which if it act at all, can produce only 
 a moiety of this force ? 
 
 On the other hand, have not we a theory which gives a 
 distinct idea of the cause of these phenomena ? One moiety 
 of the force of the discharge comes from the change of 
 level, the unused rotary force resolved into other mo- 
 tion ; the other moiety, from the resolution of molecular 
 force into progressive motion. United they are sufficient 
 again to raise the water, as it flows into another recep- 
 tacle, to the height from which it fell, the spare force of 
 rotation being again transferred to rotation, the molecular 
 force being again translated into the atomic action due to a 
 depth equal to that from which the water issued. 
 
MECHANICAL PHILOSOPHY. 191 
 
 Practical men recognize these principles in the construc- 
 tion of their machinery. The molecular force distributed as 
 the counterpart of the rotary, increases regularly from the 
 lower surface upward. As a cone, with its base at the 
 lower stratum, and its apex at the upper, must be divided 
 at one third of its altitude, to leave equal quantities in each 
 portion, so the molecular force is divided ; the centre or 
 equilibrium of power in every column, whatever its height, 
 is at one third of the altitude from the lower surface. To 
 support a sluice, or flood-gate, or embankment, the support 
 is made to press at one third of the height. 
 
 A practical millwright, on being asked if it made any 
 difference how the water was let on to his wheel, replied, 
 " On the overshot or vertical wheel it does not make any 
 difference ; in whatever way the water runs out, I get its 
 whole weight as it strikes the wheel ; but I confine that 
 which issues from below on the central, or horizontal wheel, 
 so that it shall not spread until it strikes the wheel, for 
 thereby I get the 4 spring' of the water." " But you know 
 that water is incompressible ; how can it have a spring ? " 
 " It may be so," replied the mechanic, " but I know that 
 water issuing from below has a spring to it." 
 
 We are far from having exhausted this branch of the sub- 
 ject ; but, as it has already occupied an undue share per- 
 haps of our space, we pass to a cursory consideration of the 
 ebullition of water, and of the action of steam. 
 
 By recognizing the action of molecular force, we are ena- 
 bled to comprehend a peculiarity of water in its conduction 
 of heat. It is almost impossible to heat water from the sur- 
 face downwards. Heat can hardly be propagated in this 
 direction through the fluid. If it is applied at the surface, 
 the upper stratum only receives the force, and is converted 
 
192 OUTLINES OF A SYSTEM OF 
 
 by it into vapor, which passes off. But when the lower 
 stratum receives the force, it distributes it normally through 
 the volume, the molecular action being gradually increased 
 until ebullition, that is, vaporization from every stratum, 
 ensues. The lower strata, not the surface, regulate mole- 
 cular action ; without the application of artificial heat, it is 
 additional depth which increases its intensity. The force 
 thus acting in the lower stratum determines that of all the 
 succeeding strata ; therefore, it is only by artificially increas- 
 ing the force of the lower surface, that this increase can be 
 extended through the whole volume. Our views receive 
 confirmation from the fact, that water artificially heated is 
 always hottest at the bottom of the vessel ; in very deep 
 boilers, the liquid is much more heated than it can be in 
 smaller vessels. 
 
 When there is no application of artificial heat, the mole- 
 cular force present in water depends upon the degree of 
 rotary force. Therefore water boils with less added heat, 
 according to the degree of its elevation. At a great alti- 
 tude, as water is already in possession of a high degree of 
 rotary force, it does not require so much additional force 
 to bring the molecular action to that degree of intensity 
 which changes it into steam. At the summit of Mont Blanc 
 water boils at 180 of Fahrenheit, 32 less than at the 
 level of the ocean. By the changes of rotary force upon 
 the surface of the earth, vaporization from water, and even 
 from snow and ice, is induced and suspended. This vapor 
 is not expansive, having space for its range of molecular 
 motion. 
 
 Steam has, of course, a most intense molecular action, 
 and, when generated under confinement, it has not sufficient 
 range of space for its normal motion. Hence its expansive 
 power. 
 
MECHANICAL PHILOSOPHY. 193 
 
 Ebullition does not, in the least degree, depend upon 
 atmospheric pressure. Air, in its normal condition, does 
 not act upon water. But if air be artificially condensed 
 over water, as in a steam-boiler for instance, by the rising 
 of steam in it, there is then a pressure of the air upon the 
 water, and there is less space for the water to diffuse itself. 
 When closely confined, without space for enlargement, water 
 can be heated red hot without passing into vapor. The de- 
 gree of the confinement therefore measures the resistance to 
 the change of water into steam. In practice, the resistance 
 is the impelling force which moves the piston. Hence the 
 importance of confining steam in as small a compass as pos- 
 sible, and not allowing it to expand except in that direction 
 in which, by the act of expansion, it can move the machin- 
 ery. The force of steam is its demand for greater space for 
 its molecular action. That attained, it is no longer the 
 source of motive power. It cannot be recompressed with- 
 out the use of as much force as it would give out by its re- 
 enlargement. Great expense is often incurred by the want 
 of a clear understanding of this principle. In an artificial 
 vacuum on the other hand, there is greater space for the 
 molecular action of the remnant of air than is normal to it, 
 and if water is placed in the vacuum, the equilibrium is 
 restored by its vaporization. So great at times is this va- 
 porization, that there is not force enough left in the remain- 
 ing water to preserve its fluidity, and it becomes frozen. 
 
 The increased capacity of water for heat in proportion to 
 its depth, to which we have alluded, is of course attributed 
 to the pressure of the upper water, which is supposed to pre- 
 vent the escape by vaporization of the heat from the pressed 
 strata. Can this be a well-founded opinion, since gravitation 
 neither directly nor by pressure can have power over heat ? 
 
 17 
 
194 OUTLINES OP A SYSTEM OF 
 
 Nor is it necessary that there should be vaporization to pro- 
 duce an equal diffusion of heat throughout any one volume 
 of fluid. The lower strata retain the augmented heat on the 
 same principle on which they retain the molecular force. 
 The additional force of heat is diffused in a decreasing ratio 
 from the bottom to the surface of the fluid. 
 
 We will advert to another of the supposed results of the 
 gravitating power. It is believed that, if the pressure of the 
 atmosphere were withdrawn, many substances now solid 
 would become fluid, and many fluids, aeriform ; that water 
 with a slight increase of heat, would change itself into vapor, 
 were it not for the weight of the air upon it ; and that in 
 fact it is by the gravitation of the atmosphere that even the 
 ocean remains in its place. 
 
 There is one striking peculiarity in the philosophy of 
 gravitation. According to it no matter in the universe 
 moves or keeps in place without the control of other mat- 
 ter. Every particle is endowed with energy to give motion 
 to other particles ; but it has none for its own motion. Thus 
 nothing is able to take its own position, to be what and 
 where it is, from itself, from its inherent fitness ; but every 
 mass is perfectly competent to press into place adjacent 
 masses or volumes, and these in their turn to press it into 
 proper position. And this is deemed true, not of adjacent 
 masses only, but of masses millions of miles distant, and that 
 against the action of the force with which they were endowed 
 at their creation. Thus one sphere determines the orbit of 
 another, itself being guided in its turn by an emanation from 
 some other centre of influence, and hence there is order and 
 permanence in the system of worlds. 
 
 It may be said that this feature of the theory of universal 
 gravitation is not objectionable, because the order of nature 
 
MECHANICAL PHILOSOPHY. 195 
 
 may be as firmly preserved by the indirect action of matter, 
 as by the immediate power of every atom to move in its 
 destined path, and to preserve its own proper position. 
 
 It is true that, whatever be the character of our philoso- 
 phy, it cannot change the perfect and the permanent. The 
 worlds will roll on in their orbits and fulfil their appointed 
 rounds, whether we believe them endowed directly with 
 power from the hands of their Maker, or think of them as 
 under the control of other parts of the creation. But theo- 
 ries have value in proportion to their effect in strengthening 
 our conceptions of the wisdom and power by which the uni- 
 verse is continually upheld, in leading our minds upward 
 to the Great First Cause, instead of allowing them to rest 
 in the finite and the created. The first work of philosophy 
 is to divide the incomprehensible from that which can be 
 clearly apprehended, that the one may be made the subject 
 of investigation, the other be used only to lift our thoughts 
 to the wisdom and power of God. Would that every theory 
 were destroyed which furnished to the mind even the 
 appearance of a resting place between the Creator and his 
 works. 
 
 By referring the motions and positions of matter to mu- 
 tual action, we receive no clear idea, we take no step in 
 advance. We still rest on the power of matter to induce 
 motion, to do that indirectly which we are not willing to 
 admit that it can do directly. To us. and perhaps to other 
 minds, the theory that every part of the universe, each 
 atom, volume, mass, is guided by force present with it, 
 unaided by the influence or mediation of other matter, has 
 a value because it strengthens our conviction of the perfect- 
 ness of the creation, because it leads us to recognize in all 
 the changes of matter the Guiding Hand which sustains, 
 
196 OUTLINES OF A SYSTEM OF 
 
 controls, arid directs it. It presents to us every element as 
 in its place by reason of its construction, as discharging 
 its functions by the inherent fitness of its constitution, by 
 a fitness not borrowed from other matter, but imparted 
 to it at once from the Source of all perfection. It brings 
 before us general order from the perfectness of each part. 
 We recognize in harmony of action, as it were a sympathetic 
 movement, not a compelled conformity, not the equilibrium 
 of well balanced opposition. We think that every part of 
 the structure of the worlds stands firm because it was so 
 created, not because it is supported by the insecure 
 balance of opposite leanings from the true direction. 
 
 The ocean appears to us as a most beautiful instance of an 
 element, perfect in its adaptation to its place, in its fitness 
 to fulfil all the purposes of its creation. It is not held to its 
 bed by the pressure of the atmosphere upon it, but works as 
 if in sympathy with it ; it is not chained down to its depths, 
 but, as if exultingly, it lavishes its force to aid in the 
 harmony of the world's movement. It seems to rejoice that 
 it is, and that it acts.* Though by its constitution so 
 
 * Since writing the above we have met with the following beautiful pas- 
 sage, in an article from Kev. A. P. Peabody, in a recent number of the 
 North American Review, which has given us so much pleasure that we 
 cannot forbear transcribing it : " We are reminded in this connection of 
 an apostrophe to the sea, in the Prometheus of ^Eschylus, which, in four 
 words conveys much more to our apprehension, and reflects far more fully 
 our own unutterable emotion in the frequent survey of ocean scenery, than 
 could be done by volumes of the most glowing, eloquent, passionate de- 
 scription. Whenever we look iipon the ocean, whether from deck, beach, 
 or crag, by sunshine, moonlight, or its own phosphorescent glow, we find 
 ourselves absolutely haunted, sprighted, by these words, as they pulse upon 
 the inward ear in unison with the rhythm of the waves. The passage to 
 which we refer is that where Prometheus, in calling on all nature to witness 
 his cruel wrongs at the hand of Jupiter, addresses the sea as 
 
MECHANICAL PHILOSOPHY. 197 
 
 nearly poised between the solid and the aeriform state, it is 
 in no peril, from the vicissitudes of temperature, of losing 
 its form and condition by passing into either extreme. It 
 is not in dangerous equilibrium. Its own construction pro- 
 tects it on either hand, and its inherent safeguard strengthens 
 as the volume of water deepens. A mere surface stratum 
 only can harden into ice, or pass away in vapor. The heat 
 of the tropical sun cannot penetrate it ; under its direct 
 rays are thousands of miles of ocean surface with a perma- 
 nent and uniform temperature, and water drawn from the 
 depths, even under the equator, has the icy coldness of the 
 water of the polar seas. The unused force of rotation and 
 revolution, laid up as in a storehouse of strength, is securely 
 held in the molecular action, so that by degrees only it 
 ascends to the surface and passes off in vapor ; or by conduc- 
 tion to the air as heat mellows the rigor of winter on the sea- 
 girt shore. So securely is this force held, that from the 
 equator to 48 north and south of it, the mean tempera- 
 ture is but a few degrees above that of the air. Yet we 
 know that it has force proportional to its depth ; for the 
 thermometer will determine the presence of shoal places as 
 well as the sounding lead ; and the cold water of shallows 
 condenses the vapor of the air over them, so that often, 
 clouds, sharp and well defined, map out accurately the form 
 
 xvnuTiar tert'tQi&uov ytlaaua. This cannot be transfused without damage 
 into another language. 
 
 "Tis odor fled, 
 As soon as shed.' 
 
 We know not how to convey in current English the multiform unity indi- 
 cated by the original. ' The innumerable laugh of the sea-ivavesj is literal, 
 but awkward. ' The many tivinkling smile of ocean,' (which we copy from a 
 Lexicon,) is preferable on the score of euphony, but less adequate to the 
 sense." 
 
 17* 
 
198 OUTLINES OF A SYSTEM OF 
 
 of the banks beneath. The force regularly set free from 
 the ocean preserves the equilibrium of the atmosphere over 
 it, so that, far away from land, there are not the frequent 
 and sudden irregularities, the disturbances from conflicting 
 winds, which occur where islands break up the continuity 
 and interrupt the regular transmission of force. 
 
 We referred in a former chapter to the ocean as being a 
 storehouse of force, as the conducting element by which 
 the unused energies of rotation and revolution are redis- 
 tributed. How perfectly adapted for this purpose are the 
 oceans from their position ! There is no unbroken circuit of 
 land passing round the earth as a barrier against the passage 
 of force from one hemisphere to the other. There are few 
 broad surfaces of land which are not broken up by intruding 
 bays or inland seas. North and south around the poles, the 
 Arctic and Antarctic Oceans open free communion ; for 
 there are changes about the magnetic poles demanding trans- 
 fers of force for the restoration of an equilibrium. And 
 from the equator to the poles on either hand, between 
 which the greatest difference of temperature and of rota- 
 tive force exists, by the broad sheets of the Atlantic and 
 Pacific stretching from pole to pole, is the communication 
 kept fully open. 
 
 We now pass to the consideration of the atmosphere. If 
 a weight bearing upon the surface of the ocean were neces- 
 sary to prevent it from passing off by vaporization, the 
 atmosphere, as it is constituted, could not supply this press- 
 ure. As the air exists in its normal state, it is without 
 power to bear with force against an adjoining volume of 
 other matter. Air can press by its elastic power alone, 
 
MECHANICAL PHILOSOPHY. 199 
 
 and it manifests elasticity only when there is not sufficient 
 space for its molecular action. Its elasticity becomes appa- 
 rent by compression, it is the throwing back the force 
 which disturbs the normal position of its particles. Like 
 steam, air must have its molecular action artificially re- 
 pressed by confinement in order to manifest its elastic force. 
 The only pressure of aeriform bodies is from want of space 
 for the action of the force present with the atoms. 
 
 As the atmosphere exists in its natural state, its molecu- 
 lar force is determined, as in the case of the denser fluid, 
 water, by its degree of rotary force. Its atomic force 
 therefore increases in every stratum, from the highest to 
 the lowest, as the counterpart of its progressive force. We 
 cannot see a current of heated air pass upward without 
 noticing in its vibrations the intensity of its molecular action, 
 which, as it ascends, is absorbed in rotary motion at a 
 higher level. This atomic force, constituting elasticity when 
 under confinement, when unconfined has its normal space, 
 has all the room that it needs for its motion. Of course, 
 it cannot bear upon or press any matter in contact with it. 
 We might as well look for motive power by the expansion 
 of the free vapor rising from the surface of the ocean, as to 
 seek in unconfined air for the power of pressure. In both 
 cases the particles have freedom and space for motion with- 
 out impingement upon each other, or upon surrounding 
 matter. Nature does all things well. There is no tendency 
 in matter to escape from her adjustments. There is no 
 crowding, no contest for space. All things conform one 
 to another. Force, matter, space, are in due relation. 
 There may be an occasional oscillation, for a time a lim- 
 ited swerving from an accustomed relation, but how soon 
 the storm subsides ! It is 'not a struggle for mastery, the 
 
200 OUTLINES OF A SYSTEM OF 
 
 continued battle of contending forces, which gives the peace 
 of nature. It is, as we have said, the constituted fitness of 
 all things for their assigned place and office. 
 
 Air and water rest in contact without mutual pressure 
 because they are in place. If one causes motion in the 
 other, it is by the transfer of force. When air is artificially 
 condensed the force of elasticity manifests itself, and then 
 there is pressure ; but, as this is the effect of the unnatural 
 condition, it does not outlast the confinement. Set free, 
 the condensed air rushes instantly into the more rarefied, 
 diffuses itself where there is relatively greater space for 
 motion, and an equilibrium is at once restored. What is 
 true of a smaller, isolated volume of air, is true of the whole 
 atmosphere. The law of nature is uniform ; the same force 
 which diffuses a confined portion when it is set free, is ever 
 in unobserved action, so that the whole element is in equili- 
 brium in relation to its own particles, and in its relation to 
 other matter ; the law of its nature forbids a permanent and 
 continuous pressure upon other matter. 
 
 That air is elastic in proportion to its density has been 
 proved by the most accurate experiments, performed by a 
 commission of the French Academy of Science. To state 
 the fact in other words, the force with which air will diffuse 
 itself is in proportion to its density -compared with that of 
 the surrounding air. Elasticity, therefore, is the power of 
 diffusion, by which the pressure ceases to be, by which it 
 is annihilated in consequence of the return of the whole 
 volume to its normal condition. Thus, the elasticity of a 
 bent bow, so soon as it is straightened, no longer manifests 
 its presence, for the atoms of the bow have returned to their 
 normal state and are at rest. 
 
 What view of this subject does the theory of gravitation 
 
MECHANICAL PHILOSOPHY. 201 
 
 present ? It supposes a continued, a permanent pressure of 
 the particles of air, stratum on stratum, causing differing 
 degrees of density in every layer, the pressure decreasing 
 from the surface of the earth upward till the air gradually 
 fades away into the vacancy of space. It gives to air a 
 continued struggle for space, an abiding elasticity, an 
 elasticity acting in every direction, bearing upward as well 
 as downward. It presents the atmosphere as a series of 
 springs, increasing in the power of reaction from above 
 downward, and all of these bent springs secured at one end, 
 only with nothing to resist the expansion of the other end, 
 the elasticity of the air increasing with its density, its dens- 
 ity increasing with its depth, and this elasticity acting with 
 equal force in every direction ! We know that the expan- 
 sive power of the air throws the more dense portions upward 
 into the more rarefied. What therefore keeps down the 
 atmosphere, which, according to theory, presses upward as 
 well as downward, against itself and all other matter, with a 
 force of fifteen pounds to the inch ? 
 
 We cannot avoid the belief that the views which we have 
 presented accord more nearly with the facts. The air is 
 neither drawn down to the earth by attraction, nor repelled 
 from it by its own elasticity. It holds its place, because it 
 is so constituted as to retain the due force of rotation for its 
 level of rotation. It has no tendency to escape into the re- 
 gions of space, nor to crowd into the bed of the ocean. It 
 occupies its allotted place without an effort to expand or to 
 contract its volume. It is without elasticity when uncom- 
 pressed, without weight when resting at one level. Its 
 motion is from the reception of force, its permanency, be- 
 cause God gave to it the atomic and elementary construction 
 which fits it for its position, and for its office in the economy 
 
202 OUTLINES OF A SYSTEM OF 
 
 of nature. ' It did not fit itself for its place and function, nor 
 is it guarded and restrained by other matter as dead and 
 senseless as itself. 
 
 That gravitation cannot by its force draw down the atmo- 
 sphere, so that its density shall increase, stratum after stra- 
 tum, from above downward, or if the atmosphere exists 
 with this increasing ratio of density, that it is not the action 
 of gravitation which retains it in its position, is distinctly 
 proved by the operation of the air-pump ; for the compara- 
 tively denser air of the receiver invariably rises, against the 
 attraction of the earth, into .the rarer medium between the 
 valves. Thus against gravitation would the denser air near 
 the earth rise up into the more rarefied strata above, till an 
 equilibrium of density was established. " We know not," 
 says Dr. Arnott, " at what distance the gravity of the par- 
 ticles of air becomes just a balance to their repulsive force, 
 and therefore know not what the degree of rarity is at the 
 top of our atmosphere, but we see that it must be exceed- 
 ingly great from the fact that the air left in the receiver of 
 an air-pump has still spring enough to lift the valve of the 
 pump, when there is less than one thousandth of the original 
 quantity remaining.'' If the air in the receiver has 
 " spring " enough left for its elevation, though so vastly 
 reduced in density, why is not the spring of the denser 
 strata of the atmosphere a sufficient force for their elevation 
 into the more rarefied ? 
 
 This illustration introduces us to the next branch of our 
 subject, the vacuum. We do not entertain the idea that 
 nature abhors a void place, but we believe, to speak meta- 
 phorically, that nature abhors and resists the infraction of 
 her laws, one of which is, that force shall be equably 
 diffused according to altitude. Force, in distributing itself, 
 
MECHANICAL PHILOSOPHY. 203 
 
 will carry into a void place the adjacent matter, so that in 
 the onward current of rotation there shall be no vacant 
 space. The fall or rise of matter from the stream at one 
 level into the stream at another, is but the interchange of 
 place of equal volumes. In the creation of a vacuum, 
 however, there is a change without the equipoising change, 
 and the filling of a vacuum, whenever it takes place, is the 
 same act as if the equipoise had been preserved when the 
 matter was first removed. Thus vacua are filled, let the 
 time be never so remote from their formation, whenever the 
 adjacent matter is susceptible of the change of form neces- 
 sary for the purpose, and filled with the same degree of force 
 with which they were made void. Air, extensible without 
 limit, will always fill a vacuum, as will water and other fluids 
 to the limit of their extension ; solids will be forced against or 
 into it to the degree that their form and elasticity will permit. 
 To repeat the idea ; the force used to create a vacuum 
 measures the force with which it is filled. For instance, if 
 the air be drawn from a vessel, the force which will cause 
 other air to rush into it, is equal in intensity to that which 
 displaced the air. The force required to fill a vacuum is 
 not determined by the gravity of the external air, for that 
 must be invariable. Matter lifted up does not increase in 
 weight according to the distance to which it is lifted, nor has 
 it more weight of air over it when elevated one foot than when 
 raised six inches ; yet the higher a piston is lifted in making a 
 .vacuum, the more force is required, and with the more force 
 does it return. Suppose a tube in which, by the elevation 
 of a piston, a theoretically perfect vacuum is formed. The 
 air is believed to press upon every inch of the surface of the 
 tube and piston with a force of fifteen pounds. Raise the 
 piston one foot, the air bears on its outside surface fifteen 
 
204 OUTLINES OP A SYSTEM OF 
 
 pounds per inch ; raise it six feet, the weight of the atmo- 
 sphere over it has not been increased ; its pressure remains 
 the same, but the higher it is drawn the more force has been 
 required to lift it, and the greater is the force with which it 
 returns. The strength of the " fuga vacui " is not there- 
 fore caused by the unchanging weight of the atmosphere. 
 It is measured by the force which produced the void place, 
 in other words, by the extent of the vacuum, and of course 
 does not depend on the unvarying weight of the column of 
 air over it. 
 
 To vary the illustration we would refer to the " Magde- 
 burgh hemispheres," as they are called. Two hollow half 
 globes of metal are fitted to each other, so that their lips 
 when touching may be air-tight. Exhaust the air within by 
 an air-pump, and then " a force is required to separate 
 them of as many times fifteen pounds as there are square 
 inches in the area of the mouth, or at the surface of the 
 division of the upper and lower hemispheres." The force 
 holding them together is not therefore the gravity of the 
 atmosphere ; for, if the vacuum were perfect, the external 
 pressure would be in proportion to the surface exposed, to 
 the surface area of the sphere, not, as is the case, to the size of 
 the vacuum measured by its diameter. It is said that, when 
 these hemispheres were first exhibited, the inventor had a 
 pair made of a foot in diameter, and that six horses were 
 unable to pull them asunder. Suppose the metal to be 
 thicker, so that the vacuum would be only half the size, 
 We know that much less force would be required to pull 
 them apart, and yet the weight of the atmosphere around 
 them would remain unchanged. 
 
 Thrust down a piston so as to condense the confined air 
 beneath it, it will be driven back with the force with which 
 
MECHANICAL PHILOSOPHY. 205 
 
 it was thrust down. Elevate a pistoti so as to rarefy the con- 
 fined air, and it will be drawn down with the force with which 
 it was elevated. The force of the readjustment is related 
 only to the void place, not to the weight of surrounding air, 
 to the extent of the disarrangement, by no means to the weight 
 of the medium in which the void place is made. There is 
 one degree of force pervading the atmosphere, giving to 
 each of its atoms its relative position. Let there be an 
 abnormal position of the particles of any volume of air, and 
 the force that gave the normal position of the atoms, will be 
 the measure of the force required to restore it to its former 
 state. In other words, the force of position is invariable. 
 But let it be granted that it is by the pressure of the air 
 that a vacuum is filled, the pressure can be caused only 
 by the elasticity of the air, or by the power by which it en- 
 larges its volume wherever there is space. If we allow the 
 air to have this elasticity, every fact of its action relative to 
 the vacuum is explained, and the elasticity could exist as 
 well without as with the attraction of the earth. Gravita- 
 tion therefore is not the essential condition for the pressing of 
 the atmosphere into a void place. Elasticity in fact supplies 
 a better explanation, and this may exist without attraction. 
 But we consider the atmosphere in its normal state as 
 without elasticity. The action of elasticity being only in- 
 duced by a disturbance of the relative density of its parts, 
 its action, so far from being permanent, is remedial, curative, 
 leading to equal diffusion of the atoms of the atmosphere 
 through space. Therefore the air is of uniform density, 
 therefore are the void places filled. Imagine in the ocean 
 an unfilled spot, surrounded by water moving in rotation 
 with a force of one thousand miles an hour, the particles of 
 water not pressing on one another, the force being equally 
 
 18 
 
206 OUTLINES OF A SYSTEM OF 
 
 diffused, each atom having its exact proportion ; into 
 this void place the water will enter, and it will be filled, 
 force diffusing itself equally in the whole stream, and at the 
 same time equally diffusing the atoms of the stream. Thus it 
 requires great strength in the walls of the vacuum to keep 
 out the flowing stream of air ; the force by which nature 
 seeks to fill it is the force by which the matter of the uni- 
 verse is kept in constant motion. 
 
 This view impresses the mind with the permanency of 
 nature, with the never-varying intensity of her force. 
 However long a vacuum may continue, the force of the 
 return will be the force of withdrawal, and thus, while the 
 position and movement of the sphere is ever rigidly deter- 
 mined, so is the position and movement of the most minute 
 fragment, of the very atoms composing the fragment, by an 
 ever acting, unchanging power. Minor changes take place, 
 there is a limited elasticity which permits condensation and 
 rarefaction, alterations of form, variation of motion ; but the 
 law preserving the general harmony is never repealed, it 
 remains in constant operation. The force that disarranges 
 measures the force which readjusts ; the void place is filled 
 to restore perfection, completeness, but never filled by the 
 disturbance of other elements. They too have their laws, and 
 a void in the air, can be filled with water to a limited extent 
 only ; for the energy of nature is used for preservation alone. 
 
 In passing, we turn our attention for a moment to the 
 level of water when in contact with the atmosphere. The 
 even surface of an undisturbed volume of water, the well 
 defined line which gives distinctness to the volumes of the 
 separate fluids, has been usually traced to the action of 
 gravitation. 
 
 In speaking of chemical affinity, we referred to the equal 
 
MECHANICAL PHILOSOPHY. 207 
 
 diffusion of force among combining atoms as the necessary 
 condition of combination. We look upon matter as com- 
 posed of simple elements, and upon these elements as pos- 
 sessing different relative capacities for the retention of force. 
 If the simple elements in contact do not equally diffuse the 
 present force, there cannot be the harmonious molecular 
 action which alone can unite them as one mass or volume ; 
 if the force be equally diffused, there ensues that sympathy 
 of atomic action which is the bond of cohesion. Without 
 this provision contact would determine combination, and in 
 the place of established order, of distinctly characterized 
 masses, all things would be mingled in chaotic confusion. 
 There would be 
 
 " Neither sea, nor shore, nor air, nor fire, 
 But all these in their pregnant causes mixed 
 Confusedly." 
 
 While we believe that there is a certain intensity of force 
 and its equal diffusion, which locks together the fitting ele- 
 ments of every structure, which produces the various and 
 distinctly characterized solids and fluids ; so after their 
 construction, by the operation of the same principle, are 
 they kept separate and distinct. Air and water, for in- 
 stance, though they may be somewhat mingled mechan- 
 ically, though for a time their meeting surfaces may be to 
 a degree made irregular, continue to be distinct volumes, 
 ever returning to a fixed relative position. When at rest 
 their line of separation is a perfect level ; the position of one 
 is invariably above the other. It is because the one in all 
 the transfers of force retains permanently the greater share, 
 that its level of rotation is superior. 
 
 If a vessel containing water has pipes issuing from it of 
 various shapes and diameters, the volume of water will retain 
 
208 OUTLINES OF A SYSTEM OF 
 
 the same level in all of its divisions. The water receives 
 that degree of force only, which, while in contact with air, 
 gives it its place below the air, and this force being equally 
 diffused throughout the volume, the force of rotation and the 
 force of molecular action are the same in every part, resulting 
 in a uniform surface level. It is from this principle, that 
 issuing streams may rise to the altitude of their foun- 
 tain, that water running through conducting pipes, what- 
 ever may be their enlargement or contraction, their length 
 or windings, knows the level belonging to its volume. We 
 cannot conceive of this uniform level being produced by the 
 downward tendency of the particles of the water. But the 
 reason of it appears evident when we consider it as the outer 
 circle of rotation, determinately fixed by the degree of its 
 impelling force. It is from this principle that the vast 
 ocean, constituting almost a liquid world, though agitated 
 by winds, though swollen by tides, though traversed by 
 wide-extending currents, preserves the curve of its sur- 
 face, the alternations marked upon its shores showing 
 that its changes, like all changes in nature, are limited and 
 periodic. The ocean is not a collection of particles gravi- 
 tating independently of each other, nor is the shape of its 
 volume preserved by the tendency of each atom to the 
 centre of attraction. It is a whole, animated as it were 
 with one life diffused through every part, 
 
 An explanation of the water level by the theory of gravita- 
 tion has been attempted, and the explanation has been accept- 
 ed, not as sufficient and satisfactory, but as the best possible 
 in accordance with the theory. Suppose a vessel containing 
 one thousand pounds of water, with a pipe extending up- 
 wards from its lower part of a size sufficient to contain only 
 five pounds ; the water stands at the same level in both, 
 
MECHANICAL PHILOSOPHY. 209 
 
 One would suppose that the weight of water in the larger 
 vessel, its constant tendency to descend, would force the 
 small quantity upward so that it would escape from the open 
 pipe. Gravitation asserts that the small column is acted 
 upon only by a column in the large vessel of equal area to 
 itself, and that all tfce water except this column is held in 
 place by resting on the sides and bottom of the containing 
 vessel. But, as we have seen, any downward force actually 
 applied to the water is not resisted by the vessel, but shows 
 itself at once by the issue of water from the orifice. We 
 believe that the same level is maintained by both columns of 
 water, because there is no downward tendency in either, 
 because the water is one volume, and has its rotative force 
 equally diffused through all its parts. 
 
 We pass to some further considerations respecting atmo- 
 spheric pressure. The theory of gravitation assigns to the 
 atmosphere, as we have several times had occasion to repeat, 
 a pressure of fifteen pounds on every inch of surface with 
 which it is in contact. It therefore bears upon the body of 
 a man of average size with a force of thirty thousand pounds. 
 If this pressure were not purely theoretical, it would be felt. 
 We should be conscious of it ; we should not be compelled 
 to go to books for our first information respecting it. Its 
 intensity would be too great for concealment ; it would de- 
 clare its presence by its effects. That it is not felt is 
 accounted for by the assertion that it is equal on every part 
 of the body. " There is," says a popular writer on philo- 
 sophy, " a difficulty at first in believing that a man's body 
 bears this pressure while he remains altogether insensible to 
 it. But such is the fact, and the reason of his not feeling 
 it is that it is perfectly uniform all around. Fishes are at 
 
 18* 
 
210 OUTLINES OF A SYSTEM OF 
 
 ease in a greater weight of water, and men walk on the 
 earth without discovering a heavy atmosphere about them, 
 which, however, will instantly crush together the sides of a 
 square glass bottle emptied by the air-pump, or even of a 
 thick iron boiler, left for a moment by any accident without 
 
 the counteracting internal support of steam or air In 
 
 general, the pressure on one side of a body is balanced by 
 the equal pressure on the other, and it is on this account 
 that philosophers were so long in discovering it at all, and 
 that half-informed persons are still disposed to doubt its 
 existence." 
 
 We must number ourselves with those who still doubt. 
 How its uniformity, its equal distribution on every part of 
 the surface of the body, exterior and interior, can destroy 
 this enormous pressure, or rather how it operates to prevent 
 its being sensible, has never been explained. The equality 
 of its action could not annihilate the force. If the air 
 presses on all sides of the body, it must press together the 
 sensitive particles constituting the body. 
 
 But it is well known that the human frame is so consti- 
 tuted that it is impossible for the air to exert its pressure 
 uniformly. There are cavities in the body which contain 
 air. Now as the pressure on the outside varies in intensity, 
 sometimes a thousand pounds in an hour, according to the 
 indications of the barometer, what is to enable the small 
 quantities inclosed to maintain so nearly a counteracting 
 pressure, that in the continual variations of weight outside 
 no sensation is perceived ? In the cavity of the ear, for 
 instance, there is air which is supposed to resist the outward 
 weight ; but in order to resist this changing burden, to 
 maintain the equilibrium which prevents it from being felt, 
 this internal air must continually change its own pressure. 
 
MECHANICAL PHILOSOPHY. 211 
 
 To do this ifc must be increased or diminished, and the 
 flowing of air into and out of the orifice would constitute 
 it a perfect barometer. 
 
 But while some organs of the body have cavities contain- 
 ing air, which may assist them in supporting the external 
 pressure, there are .-others, the brain for instance, which 
 have to bear all the changes of pressure without any internal 
 support. A well educated physician remarks, " How the 
 delicate organs of the human body bear the pressure which 
 gravitation assigns I know not. It is nob because of con- 
 tained air which resists the pressure. Air within the organs 
 would be death. A very slight pressure on the brain, 
 that of a few ounces only, is attended with loss of con- 
 sciousness, yet the varying density of the air changes the 
 pressure upon it by many pounds, and I am yet to learn that 
 the brain contains air, which, by corresponding changes, 
 could neutralize the exterior pressure." 
 
 But in their eagerness to prove the existence of atmo- 
 spheric pressure, some philosophers, forgetting that the 
 principle of -its equable pressure forbids any perceptible 
 result from it, either for good or evil, assert that it exerts 
 an important influence on the animal organization. Doctor 
 Arnott, whom we have before quoted, remarks, " The atmo- 
 spheric pressure on living bodies produces an effect which is 
 rarely thought of, namely, its keeping all the parts about 
 the joints firmly together by an action similar to that on 
 the Magdeburg hemispheres. The broad surfaces of bone 
 forming the knee-joint, for instance, even if not held together 
 by ligaments, could not, while the capsule surrounding the 
 joint remained air-tight, be separated by a force of less than 
 
 a hundred pounds In the loose joint of the shoulder, 
 
 this support is of greater consequence. ... In all joints it is 
 
212 OUTLINES OF A SYSTEM OF 
 
 the atmospheric pressure which keeps the bones in such 
 steady contact, that they work smoothly and without noise." 
 If there is an unequal pressure on the bones and ligaments, 
 so there must be on the nerves, veins, arteries, and other 
 soft portions of the body, for these are as destitute of inter- 
 nal air, enabling them to resist the outward pressure, as are 
 the bones and joints. It is indeed strange that with bodies 
 so delicately organized, with perceptions so keen that the 
 slightest motion of the air, the mere breath of the breeze 
 fanning the cheek, is distinctly perceived, we should remain 
 unconscious of this thirty thousand pound pressure, or of its 
 continual fluctuations. 
 
 We are frequently amused at the effects which are attri- 
 buted to the variations of atmospheric pressure. The city 
 of Cerro de Pasca is some fourteen thousand feet above the 
 level of the sea. Men, women, and children live in this 
 city, and probably live comfortably there, notwithstanding 
 its elevated site. Cats, however, cannot exist in it ; they 
 die in convulsions in a few days after being carried there. 
 And the reason given to account for this fact is, the altitude 
 of the city, and the consequent rarefaction of the atmo- 
 sphere ! Even Humboldt gives this opinion the sanction of 
 his authority, although it is well known that the extent of 
 lungs, and consequent quantity of air received at each in- 
 spiration, in any species of animal, is in proportion to the 
 vivacity of its movements, and of course all animals would 
 equally feel the withdrawal of any portion of it. Therefore 
 a diminution of air that would be fatal to cats, would be in- 
 jurious also to every other animal. Again, it has been 
 stated, that some animals in the mountainous regions of 
 South America, when hunted by dogs, bleed from the mouth 
 and nostrils. This also is imputed to the extreme rarity 
 
MECHANICAL PHILOSOPHY. 213 
 
 of the air. Are not fright, fatigue, and accelerated circula- 
 tion, sufficient to account for the fact, without referring it to 
 the thinness of the air, especially when we remember that 
 over-driven horses at the ordinary level of the earth's surface 
 often exhibit the same symptom ? 
 
 It is believed by many that the sensations experienced on 
 the summits of very high mountains, are incontrovertible proof 
 of the diminished density of the atmosphere. Unquestionably 
 the act of ascending by personal effort to a great altitude, 
 affects the animal organization. It demands an immense 
 amount of muscular exertion, and it is no wonder that the 
 effort is followed by difficulty of respiration, languor, nausea, 
 and other uncomfortable feelings. Instances are given in 
 which blood has gushed from the lips, eyes, and nostrils. 
 Humboldt says, " in the dangerous ascent of the mighty 
 Chimborazo, after incredible efforts, at sixteen thousand feet 
 elevation, we began to bleed at the mouth, nose, and eyes." 
 It is not wonderful that, with the full belief that the air was 
 of only half its usual density, this fact should have been 
 imputed to the removal of its accustomed pressure ; though 
 it is difficult to say exactly on what principle a reduced, yet 
 still equal pressure on the whole body could force the blood 
 from its containing vessels, though it can readily be seen 
 that accelerated circulation from intense exertion might pro- 
 duce the hemorrhage. Many a mouse has been killed by 
 an air-pump without having its blood forced from its mouth ; 
 why should the partial vacuum of a great altitude produce 
 this effect ? There is no cavity of the human body contain- 
 ing air which has not a communication with the external air, 
 and by the natural channels an equilibrium could be much 
 more easily readjusted, than by the lesion of the blood- 
 vessels, 
 
214 OUTLINES OF A SYSTEM OF 
 
 In looking over Saussure's account of his ascent of Mont 
 Blanc, we came to the conclusion that it was impossible that 
 the painful bodily sensations which he describes should have 
 been produced by the rarity of the air. We observed that 
 twenty men passed the night when near the summit, crowded 
 together in a hole dug in the snow, and covered with a tent- 
 cloth to protect them from the intensity of the cold, thus 
 almost excluding the little air that remained ; and that the 
 respiration of the party at the summit, instead of being more 
 full and deep, as if nature would make amends for the thin- 
 ness of the air by the greater quantity inhaled, was almost 
 suspended. When Saussure's attention was engrossed by 
 his barometrical observations, he almost forgot to breathe ; 
 it was an effort, an act requiring the impulse of the will. 
 He remarks, " all experiments attended with care caused 
 fatigue in this rarefied air, and that because without thought 
 you hold your breath" In the descent, long before they 
 had reached air of effectively increased density, all the 
 painful sensations ceased. It was the act of descending, not 
 the level they had reached, that was the restorative. Saus- 
 sure accounts for the unexpected relief by saying, " As the 
 motion in descending does not press the diaphragm, it does 
 not confine the respiration, and one is not therefore obliged 
 to stop so often to take breath." The party passed the 
 night at a spot only about six hundred feet lower than their 
 resting place of the preceding night, where they had expe- 
 rienced so much suffering. Saussure continues, "We supped 
 with a very good appetite, and I made my observations 
 without any obstruction from indisposition." 
 
 It is the circumstance of ascending by one's own effort 
 that creates the bodily distress. We are supported in this 
 opinion by the results of ascents in balloons ; for, though a 
 
MECHANICAL PHILOSOPHY. 215 
 
 greater altitude has been thus gained than the highest moun- 
 tain summit ever reached by man, and consequently the air 
 has been according to theory proportionally diminished in 
 quantity, yet the aeronauts suffer no inconvenience on this 
 score . In a former chapter we gave one authority for this fact ; 
 we will now quote from Watson's Practice of Medicine. " A 
 diminution of the circumambient weight of the atmosphere 
 is supposed in some cases to bring on hemoptysis. Blood is 
 said to have been forced from sound lungs in persons who 
 have ascended high mountains, where the atmosphere is 
 rare, and where its pressure is sensibly lessened. Perhaps 
 the labor of ascent may have shared in the production of the 
 hemorrhage, for I am not aware that any such effect has 
 ever occurred to persons who have much more rapidly 
 reached a very great altitude in balloons." 
 
 If the painful sensations complained of were the results 
 of a decreased supply of air for respiration, the discomfort 
 would be experienced by all persons, and under all circum- 
 stances, at the same altitude. The strong as well as the 
 weak would feel the loss of air, the bold as well as the timid. 
 The same altitude however differs in its effect on different 
 individuals, and on the same individual at different times. 
 We extract the following passage from Ramond's Ascent of 
 Mont Perdu, the highest summit of the Pyrenees : " I 
 continued two hours on this summit, during which time no 
 being that had life had come within my sight except an 
 eagle, flying with inconceivable rapidity. We breathed 
 without any difficulty in this rarefied air, found by so many 
 so insufficient for respiration. I have been myself more 
 than once or twice witness to persons of hale and vigorous 
 constitutions being obliged to forego proceeding to heights 
 much beneath this. Even Saussure, upon the defile of the 
 
216 OUTLINES OF A SYSTEM OF 
 
 Giant, where the air was by no means so rarefied, experi- 
 enced an oppression of breathing by somewhat more than 
 common exertion, but here we felt nothing of the kind. . . . 
 So far from occasioning any weakness, it seemed rather to 
 add to my strength and invigorate my spirits." The only 
 effect of the elevation that E/amond specified was a more 
 rapid circulation, indicated by an acceleration of the pulse, 
 and some feverish sensations. 
 
 As another confirmation of our views, we will mention 
 that an athletic young friend of ours stated to us, after read- 
 ing Saussure's account to which we have referred, that he 
 had experienced precisely similar sensations while ascending 
 Baldface Mountain in New Hampshire, which is only about 
 four thousand feet high. He thought several times that it 
 would be impossible for him to reach the summit, so great was 
 his languor and difficulty of respiration. Several times he 
 was obliged to throw himself on the ground in a nearly faint- 
 ing state. These sensations he thought plainly attributable 
 to the difficulty of ascent, not to the rarity of the air. On 
 Mount Washington, more than two thousand feet higher, the 
 ascent to the summit of which was accomplished chiefly on 
 horseback, the only sensation which he experienced was that 
 of exhilaration. 
 
 Another friend has given us an account of two ascents of 
 Mount Washington. He remarked that, the first time, he 
 ascended on foot, and before he had half climbed the moun- 
 tain, each successive footstep painfully convinced him that 
 the air was becoming more and more rarefied. By the time 
 he reached the summit, respiration was so difficult that he 
 was rather surprised that the change in the quality of the 
 atmosphere should be so sensibly felt. His second ascent 
 was on horseback ; this time he experienced none of the 
 
MECHANICAL PHILOSOPHY. 217 
 
 former " asthmatic breathing," and at the summit " quite 
 forgot that he was respiring rarefied air." 
 
 If the quantity of air is so seriously diminished at great 
 altitudes, how is it that large cities are built at elevations 
 which ought, according to theory, to occasion great suffer- 
 ing to their inhabitants ? Among the lofty Andes are many 
 populous cities, enjoying all the luxuries of life, at heights 
 equal to that where Saussure and his companions found it 
 so difficult to breathe on account of the rareness of the air. 
 The silver mines of Potosi are wrought at a height of sixteen 
 thousand and sixty feet above the level of the sea, a height 
 nearly equal to the summit of Mont Blanc ; and the city 
 of Potosi stands at an elevation of thirteen thousand 
 three hundred and fifty feet on the declivity of the moun- 
 tain. The city of Quito, with a population of seventy thou- 
 sand, is nine thousand feet above the sea. Among the 
 Highlands of Thibet also are cities standing at great alti- 
 tudes, and surrounded with such luxurious vegetation, that 
 Chinese writers, it is said, describe them as regions of 
 pleasure. In this connection we will mention that a series 
 of meteorological observations, continued for twenty-four 
 hours in succession, has recently been made on one of the 
 summits of this range, at the height of eighteen thousand four 
 hundred feet, where, according to the barometer, the air 
 was of less than half its usual density, and " the chief re- 
 sult was, that the curves followed very nearly the same 
 changes that they were observed to do in the lower regions." 
 
 Vegetation does not appear to be affected by altitude in 
 any other manner than as the height diminishes the mean 
 temperature. Different species of plants become dwarfed, 
 and then disappear as the elevation increases, just as they 
 become dwarfed and disappear as we proceed from the equa- 
 19 
 
218 OUTLINES OF A SYSTEM OF 
 
 tor towards either pole. In central Europe the decrease of 
 heat is 1 8' for every five hundred and thirty-four feet of 
 vertical elevation ; an ascent, therefore, of two hundred and 
 fifty feet is equivalent to a progress of about one degree of 
 latitude. Alpine plants are commonly covered with a thick 
 and close down, which, as has been remarked, is analogous 
 to the soft fur of northern animals. This Alpine vegetation 
 occurs at regularly decreasing elevations as we advance 
 northward, and in the Arctic regions it is the vegetation of 
 the plains, where the temperature is the same as at the 
 lofty summits of the equatorial zone. The plants of Alpine 
 heights have been successfully cultivated on the plains 
 below, when due care has been taken to give them the 
 peculiar treatment required. 
 
 But it is supposed that the great difference of atmospheric 
 pressure ought to affect vegetation, and consequently a 
 difference between plants indigenous at different levels has 
 been traced out. " The influence of atmospheric pressure," 
 says a distinguished naturalist, " seems to me particularly 
 evidenced in the great, I may say the prevailing number of 
 Alpine species endowed with a volatile fragrance, which 
 adds so much to the sweet and soothing influence of moun- 
 tain rambles ; whilst the northern species, however similar 
 to those of the Alps, partake more or less of the dulness of 
 the heavy sky under which they flourish. " He adds, how- 
 ever, " It would be a mistake to ascribe to reduced atmo- 
 spheric pressure the peculiar aspect of most plants in the 
 higher Alps." May we not consider this fanciful proof of 
 the pressure of the atmosphere, rather as an expression of 
 the poetical idea, that science often values the bouquet in 
 proportion to the labor of gathering it, and that, as men 
 ascend above the defilements of earth, the sweeter is the 
 aroma which nature sheds in their path ? 
 
MECHANICAL PHILOSOPHY. 219 
 
 As we have before said, Nature, so far from hiding from 
 view, throws herself open to the sight. Bj change in the 
 mode of her action she appears to invite inspection, by 
 presenting herself under many aspects she seems to courfc 
 our examination. Were the earth but one unvarying plain, 
 many of her processes which are now fully exposed, would 
 remain hidden. The mountain transports the northern vege- 
 tation to the tropics, causing the polar plant to send forth 
 its fragrance under the rays of the vertical sun ; it throws 
 up the strata of the earth, as it were for examination ; it 
 collects together the extremes of temperature ; it places side 
 by side the burning lava and the never-thawing snow, thus 
 condensing world-wide phenomena, that their relations one 
 to another may be perceived at once. It displays not only 
 physical results, but the forces which control them, showing 
 us in miniature the results of the variations of rotary force, 
 the successions of climate, and the changes of electric in- 
 tensity. Every fact therefore connected with the " cloud- 
 capped " mountain, becomes full of interest to all who seek 
 to understand the organization of the world, and to trace out 
 the laws which govern its elements, none more so than 
 the enveloping wreath of vapor which has furnished its 
 poetic epithet. 
 
 " In the tropical region of Paramos," says Humboldt, 
 " at an elevation of between twelve and fourteen thousand 
 feet, some species of large-flowering, myrtle-leaved Alpine 
 shrubs are almost constantly bathed in moisture, affording 
 evidence of the frequency of aqueous precipitation, as do 
 the frequent mists with which the lovely plateau of Bogota 
 is covered. Mists arise and disappear several times in the 
 course of an hour in such elevations as these, and with a 
 calm state of the atmosphere. These rapid alternations 
 
220 OUTLINES OF A SYSTEM OF 
 
 characterize the elevated plains of the chains of the Andes." 
 By this condensation is furnished from the humid atmosphere 
 the supply of force required by the high level of the moun- 
 tain, the moisture being brought to it from the beds of the 
 ocean, which we have described as the storehouse of force. 
 Every consideration is interesting which brings to our 
 thoughts that mighty Power, which, while it supplies the 
 wants of the inorganic world, provides also its banquet for 
 the wayfaring sparrow. 
 
 To return from what may appear a digression, we omit, 
 for want of space, a physiological view of our subject which 
 had been prepared ; but we will observe that it is at once 
 apparent, that the act of ascending exhausts the strength, 
 the animal force, much more than the same quantity of 
 muscular movement at one level. The ascent of a single 
 flight of stairs is felt by the weak, and the strongest expe- 
 rience some difficulty of respiration in rapidly mounting 
 several flights in succession. If we call to mind the fact, 
 that the ascent of a mountain is the act of lifting the weight 
 of the body to the whole extent of the elevation, that it 
 requires the rotary force for the new level to be supplied, - 
 we shall not be at a loss for the reason of accelerated respir- 
 ation, exhaustion, and of many other disturbances of the 
 animal functions. Besides these, however, there may be a 
 class of sensations experienced at a very great altitude, the 
 cause of which is independent of the muscular effort of the 
 ascent. 
 
 We know that altitude causes a difference in the electric 
 condition of the atmosphere ; positive electricity normally in- 
 creases in exact proportion to height. To the usual degree 
 of electricity the body becomes habituated, and an increase 
 or diminution of the accustomed quantity always affects the 
 
MECHANICAL PHILOSOPHY. 221 
 
 feelings. If it is lessened, there is a depression of the ani- 
 mal spirits, while a slight increase brings with it a feeling of 
 new vigor accompanied by exhilaration. Contrast the sensa- 
 tions experienced in a warm, damp summer-day, with those of 
 a clear, cold day in mid-winter. On the other hand, a greater 
 amount enervates the body by a feverish increase of the cir- 
 culation, and invariably diminishes the activity of the respir- 
 ation. We know from experience that an unusual electrical 
 excitement of the body has the effect to enervate the body, 
 flush the cheeks, and almost to suspend the breath. 
 
 The electricity of the atmosphere, by its fluctuations at 
 the surface of the earth, by its changes according to eleva- 
 tion, and its differences according to the seasons, in its silent 
 unobserved transfers from one element to another, or in the 
 sudden loud explosions of the thunder-storm, exercises a 
 powerful influence on the vegetable and animal organization. 
 By tracing its effects, not only on that which has life, but 
 also on unorganized matter, we shall be able to solve many 
 of the mysteries of nature. How much positive enjoyment 
 might be received, how much uneasiness and illness might 
 be avoided, by a recognition of the power over the body, 
 exercised by the electrical states of the elements about 
 us ! But this will never be, so long as gravitation is 
 regarded as the controlling cause of even bodily sensations. 
 In a damp day, when moisture mingled with the air strips 
 the body of its accustomed degree of electric force, and 
 depression of spirits ensues, we look at the sluggish vapor 
 resting on the surface of the ground, and consider it a proof 
 that the weight of the air, its pressure upon the body, is 
 diminished. So, when the cheek is flushed, and the blood 
 leaps through the veins with exhilarating power on the 
 mountain height, we again trace this opposite effect to the 
 
 19* 
 
222 OUTLINES OF A SYSTEM OF 
 
 lessened pressure of the air. And again, when by the toil 
 of ascent the respiration is hurried, and the body sinks with 
 fatigue, still no cause is sought for all these diverse effects, 
 but the variations in the space which the atmospheric par- 
 ticles occupy ! 
 
 We would mention another instance of the tendency to 
 impute otherwise unexplained phenomena to alterations in 
 the pressure of the air. It is well known that the diurnal 
 variations of the barometer are in some way connected with 
 the diurnal variations in the intensity of the magnetic force 
 as indicated by the needle. There are every day two maxima 
 and two minima of each, the maxima of one correspond- 
 ing to the minima of the other. There is also a diurnal 
 variation in the tension of vapor in the atmosphere ; and, 
 as vapor is believed to change the weight of the air, this is 
 supposed to account for the oscillations of the barometer. 
 Of course then the variation in the magnetic power is also 
 traced to the state of the atmosphere. Thus all investiga- 
 tion seems to stay itself upon the condition of the air, when 
 further research most unquestionably will show that the va- 
 riations of the barometer, and of the magnetic force, and the 
 different degrees of the tension of vapor, are traceable to one 
 cause, to the changing position of the surface of the earth 
 with reference to the centre of her movement, to the trans- 
 fers of force which preserve the equilibrium of her motion. 
 These changes, as extensive as the surface of the earth, cor- 
 responding to her daily movements, varying too with the 
 seasons as she traverses the different parts of her orbit, 
 must they not all depend upon the same cause, the force 
 which controls her daily rotation and her annual revolution ? 
 The same force which circulates through the earth permeates 
 the air, and in its changes and transfers this force must move 
 
MECHANICAL PHILOSOPHY. 223 
 
 the barometer, touch the needle, and determine the rise and 
 fall of vapor. 
 
 We asked, in a former chapter, why continue to trace all 
 the phenomena of this beautiful world to one cause only, 
 and that a cause, allowing to it all the virtue and efficacy 
 which it can reasonably claim, so inadequate for their expla- 
 nation, its only legitimate operation being to determine the 
 position of matter, the point of space which any atom 
 should occupy ? Does it not repress inquiry, and arrest the 
 mind in its search after truth ? The belief in the attractive 
 force of matter is not only the foundation of the structure of 
 our present philosophy, but it places every stone of the edi- 
 fice, and superintends even its finish and its ornament. The 
 mind has no occasion to exert itself further. By gravitation 
 is explained the act of drawing the first nourishment, and 
 the last expiring breath ; the child totters under it in its 
 first attempts to walk, and old age resists it with its staff. 
 We see only this force of senseless matter when the pendu- 
 lum swings, when the stone falls, when the vessel floats, 
 when the vapor rises, when the clouds hang heavy over our 
 heads. We trace its effect in the descending rain, in the 
 rushing of the mountain brook, in the flow of rivers, in the 
 swell of the tides, in the outline of continents, in the shape 
 of the earth, in the form of her orbit, in the rush of the 
 solar system through space. We imagine even that by the 
 whirling of " star-dust" new worlds are gradually added to 
 the realm under the sway of the attractive power of inert 
 matter ! 
 
 We pause for one moment to glance back at the extent of 
 ground over which we have so rapidly passed. The facts 
 that we have endeavored to examine are numerous and 
 varied in their character. Had we the ability, we have not 
 
224 OUTLINES, ETC. 
 
 the space to present them in their fulness of scientific detail, 
 nor is it necessary in a treatise of this nature. But we 
 have attempted in simple language, with the least possible 
 use of technical phraseology, to group together many pheno- 
 mena under a new theory for their explanation. The result, 
 in spite of errors and mistakes, we hope may tend in some 
 degree to strengthen interest in the works of nature ; for 
 in whatever light the world is viewed, in whatever aspect it 
 is considered, its beauty is apparent ; and though the offered 
 theory be rejected, it may benefit some minds to forget for 
 a moment the established explanations of things, that they 
 may see creation with a light from a new direction touching 
 some of its prominent points. If we have substituted for 
 logical deduction an allusion to the " laughter" of the exult- 
 ing wave, if in place of the formula of the mathematician 
 we have introduced a text of Scripture, if we have ques- 
 tioned the attractive power of matter, and doubted whether 
 it be indeed the cause of all the varying phenomena about 
 us, if we refuse to admit the idea that the universe exists 
 in its present form from the necessity of the case, because 
 it could not be otherwise " considering the known proper- 
 ties of matter," it is because when we look at nature, we 
 wish to see more than the mere external lineaments ; we 
 would trace out the "Indwelling Spirit" which pervades 
 every part ; which is the cause of all change, of all move- 
 ment ; which is to the universe of matter what the life of 
 man is to the body with which he is clothed. We would feel 
 
 " A presence that disturbs us with the joy 
 Of elevated thoughts ; a sense sublime 
 Of something far more deeply interfused, 
 Whose dwelling is the light of setting suns, 
 And the round ocean, and the living air, 
 And the blue sky." 
 
CHAPTER IX. 
 
 "THOUGH IT BE ONE OF THE MAXIMS OP THE TRUE PHILOSOPHY, 
 NEVER TO SHRINK FROM A DOCTRINE WHICH HAS EVIDENCE ON ITS 
 SIDE, IT IS ANOTHER MAXIM, EQUALLY ESSENTIAL TO IT, NEVER 
 TO HARBOR ANY DOCTRINE WHEN THIS EVIDENCE IS WANTING." 
 
 Dr. Chalmers. 
 
 THE tides are often referred to as a proof that the law of 
 gravitation extends to the spheres. They are looked upon 
 as the visible and tangible results of the attractive power 
 of the sun and moon over the waters of the ocean, as a 
 fact which appeals to the senses, as an evidence of the 
 doctrine adapted to the popular mind. Without the tides, 
 it is said, " the principle of the universal attraction of matter 
 would rest solely on abstruse reasoning, on abstract mathe- 
 matical deduction.' 7 The tides indeed are presented by 
 many, as settling the fact, that the law of falling bodies 
 extends upward to the spheres, giving them their motions 
 and their mutual influences. 
 
 But the tides fail altogether to answer this purpose among 
 the unscientific. It is popularly believed that the sun and 
 moon are, in some way or other, connected with the phe- 
 nomena ; how, and why, is not understood. There are 
 questions asked which the books do not answer ; doubts en- 
 tertained, which the theory of gravitation does not dissipate. 
 There is rather an acquiescence in the statements on this 
 subject, than a full and hearty assent. There is, too, a wide- 
 
226 OUTLINES OF A SYSTEM OF 
 
 spread rumor that philosophy itself, with all its strength, 
 and with all its help from abstruse mathematical reasoning, 
 is baffled in the attempt to explain the tides as a result of the 
 law of gravitation. 
 
 We believe that, if the sun and moon do attract the waters 
 of the earth, this attraction cannot produce the phenomena 
 of the tides. To strengthen us in this belief we have high 
 authority. 
 
 Professor Brande expresses the opinion that the collected 
 facts on this subject are in advance of the theory ; and that 
 these facts wait for a more accurate determination of the 
 principles of hydrodynamics, or the laws of the motion of 
 water. La Place expressed the belief that the collection of 
 more facts, at the observatory at Brest, a place well adapted 
 for observation, would account for the discrepancy of the 
 theory with the then established facts. Whewell, in the 
 Philosophy of the Inductive Sciences, says, " The tides are 
 a portion of astronomy, for the Newtonian theory asserts 
 these curious phenomena to be the result of the attraction 
 of the sun and moon. Nor can there be any doubt but this 
 is true as a general statement, yet the subject to the present 
 time is a blot upon the perfection of the theory of universal 
 gravitation, for we are very far from being able in this, as 
 in other parts of astronomy, to show that theory will account 
 for the time, magnitude, and all the other circumstances of 
 
 the phenomena at every place on the earth's surface 
 
 And what is the portion of our mathematics which is con- 
 nected with this solitary, signal defeat of astronomy ? The 
 attempts of the greatest mathematicians, Newton, Maclau- 
 rin, Bernouilli, and La Place, to master such questions, all 
 involve some gratuitous assumption, which is introduced be- 
 cause the problem cannot be otherwise mathematically dealt 
 
MECHANICAL PHILOSOPHY. 227 
 
 with ; these assumptions confessedly render the result 
 defective, and how defective it is hard to say." 
 
 Yet notwithstanding that the theory is thus questioned 
 by truly great men, it is still presented to the popular 
 mind as a proof of the law of universal gravitation. The 
 assumption that this " blot " arises from defects in mathe- 
 matical reasoning, or from ignorance of the laws of the 
 motion of fluids, is entirely gratuitous ; for, without re- 
 course to mathematics, without the assumption of any laws 
 of hydrodynamics except those universally acknowledged, 
 the discrepancy between the facts and the theory is fully 
 apparent. 
 
 We would call attention in the first instance to this incon- 
 trovertible position. The power of attraction, according to 
 the law of gravitation, and consequently the attraction of 
 any heavenly body, is inversely as the distance, and directly 
 as the quantity of matter ; or, popularly, attraction decreases 
 with the distance, and increases with the quantity of matter. 
 If this law is abandoned, the theory of gravitation is annihi- 
 lated at once ; if it be retained, the theory of the tides must 
 be abandoned. For the waters at the surface of the earth 
 are nearest to the earth, and the quantity of matter of the 
 earth is as forty-eight to one, compared with the quantity of 
 matter composing the moon. Now with this vastly inferior 
 attractive power, how can the moon's attraction overcome 
 that of the earth ? How can the moon raise the water in 
 the least degree ? A magnet of inferior power never de- 
 taches a piece of iron from a magnet of greater attractive 
 force. 
 
 Again, if the moon can raise the waters of the ocean from 
 the earth, the attraction of the earth decreases as the waters 
 go up from her centre, while the attraction of the moon 
 
228 OUTLINES OP A SYSTEM OF 
 
 increases as they come nearer to her centre. The idea, 
 then, that the moon can elevate the tidal wave one inch, 
 includes the idea that the moon can draw the waters of the 
 earth to her very surface, the grasp of the earth being 
 gradually relaxed, and the hold of the moon gradually 
 strengthened as the waters ascend. 
 
 Or else there is a focus or common centre somewhere 
 between the moon and the earth, where the gravitating 
 forces of the two spheres produce an equilibrium, and where 
 the elevated waters would remain, and be at rest, the 
 property neither of the moon nor of the earth, belonging 
 exactly to neither sphere. 
 
 If the moon attract the waters of this globe, then she 
 attracts equally all the water of one hemisphere, the 
 hemisphere nearest to her, and depresses equally all the 
 waters of the other hemisphere. We say equally, for it is 
 so practically ; theoretically the waters at the point nearest 
 the moon would be attracted more than the waters at 
 the horizon in the proportion 244. OOO 2 to 240.000 2 . The 
 result of this would be the equal elevation of all the waters 
 of one hemisphere, and the equal depression of the waters 
 of the opposite hemisphere ; and this inequality of the height 
 of the waters would be propagated round the earth by her 
 rotation. The result of this attraction by which the earth is 
 forced to relax her hold on a portion of her waters, and in- 
 crease the hold on other portions, would be a current of 
 water rushing round the globe at the rate of one thousand 
 miles an hour. 
 
 The comparative power of the sun and moon as mathe- 
 matically deduced from their different quantities of matter 
 and distances, to serve for the theory of the tides, is 
 roughly stated as twenty to forty-nine. The sun, then, 
 
OUTLINES OF A SYSTEM OF 229 
 
 has less than half the attractive power of the moon at 
 the surface of this globe. If the moon has this superior 
 attraction for one purpose, she has it invariably for all pur- 
 poses, and should manifest this superiority not only in the 
 phenomena of the tides, but in every phenomenon con- 
 nected with the gravitating or attractive power. The glo- 
 rious luminary, the centre of attraction of all the planets, 
 so large that if they were united in one mass, their aggre- 
 gate would be to the sun as a pebble to a mill-stone, stands 
 aside shorn of his power, degraded to the position of a satel- 
 lite to the moon, his humble office, in the words of the 
 theory, being " to prime and lag " the tidal wave which 
 follows the sweep of the majestic moon across the horizon. 
 The sun, when drawing apart with a force of 355,000 spheres 
 of the size of the earth, manifests not even the power to 
 uplift a little tidal wave, to follow in the wake of the enor- 
 mous wave of the queen of the skies, the solar tidal wave 
 which, if he have any power, should at times follow the 
 lunar wave easterly, and then again westerly being never 
 seen ; for even this little display of force the theory cannot 
 allow him because of stubborn facts. 
 
 But let those who uphold the theory proclaim its defects 
 for themselves. It needs not our aid to show that it is 
 utterly insufficient, and that it is an induction from the the- 
 ory of gravitation, not a deduction from the phenomena 
 which the tides present. 
 
 We make the following quotations from the article on 
 tides in the London Encyclopedia : " The reader will pro- 
 bably be making some comparison in his own mind of the 
 deductions of this theory with the actual state of things ; 
 he will find some considerable resemblances, but he will also 
 find such great differences as will make him doubtful of its 
 
 20 
 
230 OUTLINES OF A SYSTEM OP 
 
 justice. In very few places does the high water happen 
 within three fourths of an hour of the moon's southing as 
 the theory leads him to expect, and in no place whatever 
 does the spring tide fall on the day of full and new moon, 
 nor the neap tide on the day of her quadrature. These 
 always happen two or three days later." After referring 
 to some other deviations of fact from theory, which devia- 
 tions the writer accounts for by the operation of local causes, 
 he continues, " There is also a general deviation of the 
 theory from the real series of the tides. When the moon 
 enters her second quarter at noon, it is high water at Brest 
 at 8.40 instead of 9.48, which theory assigns. Something 
 similar and within a few minutes is observed at every place 
 on the sea-coast. This is therefore general, and indicates a 
 real defect in the theory. Indeed, we have no rules but 
 what are purely empyrical, or which suppose a uniform 
 progression of the tides." 
 
 The theory of the tides could not stand for a moment 
 were it not held up by the doctrine of vis inertice. The 
 indistinctness of this vis inertice- is a very convenient mist 
 to throw over the defects of the theory. If the flow of water 
 does not show itself at the right time, at the time fixed 
 by theory, vis inertice of rest holds the waters back ; on the 
 other hand, if the flow arrives uninvited by the theory, vis 
 inertice of motion brings the unwelcome presence. This 
 vis inertice has been called "a force of inactivity, a 
 forceless force, analogous to a black white, a cold heat, and 
 a tempestuous calm. For these reasons we are inclined 
 to think," continues our author, " that bodies are wholly 
 passive, that they endeavor nothing, that they continue in 
 motion or in rest by whatever begins the motion, and con- 
 tinue to move so long as the cause continues." But the 
 
MECHANICAL PHILOSOPHY. 231 
 
 property of vis inertice^ as we have said, is convenient when 
 stubborn facts will not bow to the asserted theory. Thus 
 the happening of spring tides two or three days after the 
 full or new moon can be accounted for, the tidal wave con- 
 tinuing to rise after the cause of its rise is weakened, from 
 the habit which the water has acquired of increasing its flow. 
 We copy the following explanation of one of the doubtful 
 points in the present theory of the tides, from Sir David 
 Brewster's Life of Newton. " But the most perplexing 
 phenomenon of the tides, and one which is yet a stumbling- 
 block to persons slightly acquainted with the theory of 
 attraction, is the existence of high water on the side furthest 
 from the moon at the same time as on the side next to the 
 moon. To maintain that the attraction of the moon draws 
 towards herself and at the same time from herself, seems at 
 first sight paradoxical. But the difficulty vanishes when we 
 consider the earth, and the waters on each side of it as three 
 distinct bodies placed at different distances from the moon, 
 and of course attracted with forces inversely proportioned 
 to the squares of their distances ; the waters nearest the 
 moon will be much more powerfully attracted than the 
 earth, and the earth more than the waters farthest from the 
 moon. The consequence must be that the waters nearest 
 the moon will rise from their level, while the earth will be 
 drawn away from the waters behind the earth, which waters 
 as it were will be left behind, and be in the same situation 
 as if raised from the earth in a direction opposite to that in 
 which they were attracted by the moon." Sir John Her- 
 schell explains the difficulty in a similar manner. Indeed, 
 it is probably the best solution that can be given under the 
 theory ; and it passes current without examination, notwith- 
 standing its obvious defects. One would suppose that the 
 
232 OUTLINES OF A SYSTEM OF 
 
 earth's attraction might keep the waters at the side opposite 
 to the moon close to her bosom, especially when assisted by 
 the attraction of the moon drawing in the same direction. 
 
 Gravitation, if we admit all that is claimed for it, will not 
 cover the phenomena of the tides. Imagine a miniature 
 world, with its dry land, its lofty mountains, its wide-spread 
 oceans, and its enveloping atmosphere, placed within the 
 sphere of the earth's attraction. How would the earth act 
 upon this little world ? She would draw it towards herself, 
 with a force operating equally on its every atom. If it 
 moved toward the earth through a resisting medium, the 
 more solid parts might advance more rapidly than the 
 rarer, the granite rocks than the thin air ; if it moved 
 through void space, every part would advance with equal 
 rapidity, all retaining the same relative position. 
 
 So if the earth is attracted to the moon, every atom is 
 attracted ; and, if there is any motion induced, every part 
 moves equally. Indeed, astronomers assert that " the 
 earth is constantly falling to the moon, being continually 
 drawn by it out of its path, the nearer parts more, and the 
 remoter less so than the central." But the attraction of all 
 the particles of the earth for each other, which gives it its 
 form, which moulds it into "this goodly ball," is too 
 great for the moon to separate its elements, to tear it apart 
 as it were, to elongate its mass so as to cause the tidal 
 flow. If the moon attracts the earth at all, it must be as a 
 whole, as one mass. She cannot have greater power over 
 one portion than over another of the earth's material. The 
 theory of gravitation does not give the moon elective attrac- 
 tion, by which she is enabled to move the waters of the 
 ocean, yet leave untouched the waters of the great lakes, 
 or to lift the ocean and leave unmoved the bed on which it 
 
MECHANICAL PHILOSOPHY. 233 
 
 rests. And if she can lift water away from its own centre 
 of attraction, why does she not raise the sands of the 
 desert, the atmosphere, vapor, and the descending rain ? 
 So evident is this idea, that a scientific man in France, 
 after writing a treatise on the tides in accordance with the 
 present theory, remarked, how strange it is that the moon 
 should possess this power over the waters of the ocean, 
 when we know she cannot draw towards herself a feather 
 floating above them ! 
 
 The extension of the law which is supposed to determine 
 the fall of bodies, into a universal principle pertaining to 
 all matter, is considered as one of the most important 
 achievements of philosophy. The great glory of the theory 
 is its universality, the extent of ground which it covers. 
 The tendency of philosophy therefore is, never to narrow 
 its range, but by all possible means to extend its applica- 
 tion. A fact that has once passed under its sway is held 
 with a tenacious grasp. It is withdrawn from farther 
 examination. 
 
 The theory of the tides is an instance of this. The tidal 
 wave rises up against the very law of falling bodies ; it 
 escapes from the attraction of the earth. Looking upward, 
 astronomy sees the moon, a smaller body than the earth, at 
 a great distance from it, and endows her with power to 
 overcome the attraction of the greater earth, as regards the 
 waters lying upon her very bosom. The mathematician can- 
 not reconcile the theory with facts, the scientific man looks 
 incredulous when he teaches the doctrine, and plain com- 
 mon sense absolutely refuses to believe it. Thus it remains 
 a doctrine assented to, but not believed, asserted with- 
 out being fully comprehended, declared by men of the 
 strongest minds to be a " Uot" upon the theory of univer- 
 
 20* 
 
234 OUTLINES OF A SYSTEM OF 
 
 sal gravitation. Why not boldly abandon the theory, and 
 seek for a better ? Facts will not support it, and facts never 
 change their argument. They will not do in the future what 
 they have refused to do in the past. 
 
 Our knowledge of the great tidal waves of the ocean is 
 gained only through the facts presented by the tidal ebb 
 and flow. The swelling and shrinking of the ocean is too 
 small compared with the extent of its surface to be percep- 
 tible ; for above its vast expanse there is no fixed point by 
 which to measure its altitude. But on the coasts the con- 
 sequent currents are noticed, and the rise and fall of the 
 waters can be measured. Only by these changes of level 
 on the shores, are the alternations of the great deep made 
 known. It is the tidal ebb and flow which indicate the 
 character of the tidal wave producing them. 
 
 The ebb and flow both continue for six hours, that is, 
 from elevation to elevation, and from depression to depres- 
 sion, there is an interval of twelve hours. This, however, 
 would bring the time of high water to the same hour every 
 day ; but in addition to the regular interval, a half rotation 
 of the globe, there is a lapse of time between the tides, occa- 
 sioning what is called their progression, which continually 
 retards the time of high water to that degree that the pro- 
 gression completes its period, and the phases of the tides 
 complete their revolution, returning to the same hour, in one 
 lunation, or in the time of one revolution of the moon. The 
 tide commences its flow sluggishly, gradually increasing its 
 velocity until towards high water ; it then slackens its speed, 
 and when the full height is attained, it pauses awhile until 
 the depression of the great tidal wave recalls the waters, 
 which in their ebb manifest the same increase, diminution, 
 and cessation of current. 
 
MECHANICAL PHILOSOPHY. 235 
 
 These are the daily phenomena of the tides, the extent of 
 their flow and the direction of the currents being somewhat 
 modified by local and temporary causes, such as the con- 
 figuration of the coast, and the force and direction of the 
 winds. Besides these irregular and occasional fluctuations, 
 there are also periodical changes which are important, as 
 they point to the nature and character of the producing 
 cause of the tidal wave. These periodical variations are 
 governed by the seasons of the year, by the position of the 
 moon in relation to the earth, and by the hour of the day at 
 which high water occurs. The greatest or spring tides take 
 place two or three days after the new and full moon, and 
 the smallest or neap tides at about the same lapse of time 
 from the quadratures. There is also a difference between 
 the day tides and the night tides, and between those of 
 summer and of winter. 
 
 To obtain a distinct view of this subject we must separate 
 the effect from the cause, the current running to and from 
 the coast, increasing and diminishing the waters in bays and 
 harbors, from the elevation and depression of the ocean ; we 
 must distinguish the tidal flow from the tidal wave ; for they 
 are separate and distinct in their character. The great 
 tidal wave is the vertical elevation of the waters of an 
 ocean, the tidal flow is merely a surface current, running 
 on an inclined plane, at the rate of a few miles an hour ; 
 and as the tidal wave by its rise or fall changes the inclina- 
 tion of the plane, the consequent current changes the direc- 
 tion of its flow. The tidal flow therefore is the result, not 
 the cause, of the alternations in the level of the ocean. 
 Compared with the great oceanic currents, the immense 
 westerly current of the tropics and its branches, and the 
 polar currents, the tidal flow is utterly insignificant. But 
 
236 OUTLINES OF A SYSTEM OF 
 
 all these mighty ocean currents are lifted up with the great 
 tidal waves. 
 
 To form these waves the ocean waters of the two opposite 
 hemispheres are elevated, and there is an accompanying 
 depression at the equidistant points ; and by the rotation of 
 the world each part of its surface shares in the alternations. 
 The question is, what is the impulse of this vast oscillation, 
 what the dynamic power for this alternate rise and fall of 
 the waters of the globe ? The even-balanced sea, though 
 so free to move, does not of itself lift and depress its volume. 
 There is a moving power, an impulse which gives the 
 mighty motion. As winds in passing over the surface of the 
 sea form minor waves, so is there some force which pene- 
 trates the waters, stirring them to this vast tidal pulsation, 
 swelling and shrinking them on every shore, in the bays and 
 harbors of every coast. So that instead of a dead level, or 
 a level storm-disturbed only, there are ever varying and 
 periodic alternations of surface, ministering to the wants of 
 man, and presenting to him one of the most interesting 
 phases of the " life of the world." 
 
 In all oscillatory movement, as in the swing of a pendu- 
 lum, there is a transfer of force according as the level 
 changes. The descending water gives out the no longer 
 needed force of rotation to the water rising to the higher 
 level, the mean altitude and the mean degree of force re- 
 maining ever the same. But oscillation does not furnish its 
 own impulse. To account for the tidal wave, we must recur 
 to a regular and periodic passage of force which touches the 
 waters, imparting to them their motion. 
 
 The force which causes the tidal swell must be of varying 
 intensity. We refer not to local and occasional changes, 
 but to periodic alternations in its strength. The motive 
 
MECHANICAL PHILOSOPHY. 237 
 
 power of the tides varies in degree according to the position 
 of the part of the earth at which it is high water in relation 
 to the centre of her orbit ; it varies according to the position 
 which the earth occupies in her orbit, and her position 
 in relation to the moon. In other words, the hour of the 
 day, the season of the year, and the phases of the moon 
 point to the changes in the intensity of the impelling force 
 of the tidal oscillation. It is then connected with the earth's 
 motion ; it is a branch of the same force. It comes there- 
 fore from that which is world-wide in its action, from that 
 which increases and diminishes the great movement of the 
 earth ; for we trace all its changes to the perturbations and 
 vicissitudes of her rotation and revolution. 
 
 The force of terrestrial magnetism was formerly supposed 
 to be of limited and partial action, to pertain to a class 
 of metals only ; but recent discoveries prove the universality 
 of its power over every kind of matter of which the world is 
 composed. The oxygen of the atmosphere has been recently 
 proved to be the subject of its power ; and certain crystals 
 suspended by a thread of silk are found " to take under the 
 direction of the earth's magnetism a determinate and fixed 
 direction," acting as magnetic needles, " pointing constantly 
 towards the poles of the earth, towards the magnetic poles, 
 or toward some azimuthal point." The transfers of elec- 
 tricity, once considered as the passing of matter from the 
 positive to the negative electric state, are now regarded 
 as the plus and minus in the present quantity of a pervading 
 power, and electrical phenomena are deemed the evidence 
 of a restoration of the equilibrium of force. Philosophy 
 recognizes a force flashing through the sea, permeating the 
 atmosphere, and penetrating into the solid earth. 
 
 Nor is this force spasmodic and irregular in its transits. 
 
238 OUTLINES OP A SYSTEM OF 
 
 There are permanent currents indicated by the magnetic 
 needle ; for the constant action of the needle can be caused 
 only by a continued flow of the galvanic stream ; nor is the 
 flow of uniform intensity, but it is subject to regular and 
 periodic alternations of strength. Between the tropics, 
 where by the greater diameter, and the consequently greater 
 degree of rotary force, the electrical and magnetic pheno- 
 mena are more fully developed, the hour of the day can be 
 determined " by the position of the needle, as well as by 
 the changes of the barometer." Humboldt believes in the 
 existence of many systems of magnetic currents ; he de- 
 scribes the incessant oscillation of all magnetic phenomena 
 " according to the hours of day and night, and according to 
 the seasons of the year, and according to the whole course 
 of the year," so that we are compelled to believe, that there 
 are regular and constant transmissions of force around the 
 world, to preserve the equilibrium of motion between the 
 different parts, as by their changing position there is a 
 necessary acceleration or retardation of their velocity, 
 
 In our remarks on the barometer we referred to the oscil- 
 lation of the earth's circumference, by which there was at 
 the opposite points an enlargement of the diameter, and a 
 contraction at the intermediate, equidistant points. It is 
 not the barometer only which indicates this fact. The 
 action of the needle strengthens us in this opinion. If there 
 is this swelling and shrinking, there are parts of the globe 
 which, by their wider orbit of rotation, would require the 
 greater force of propulsion, and parts which by their subsi- 
 dence would require the less. There must needs be a 
 transfer or passage of force, and, the action of the needle 
 being determined by the current of force, this transfer 
 would be indicated by its movements. Accordingly we 
 
MECHANICAL PHILOSOPHY. 239 
 
 find, that the needle has its two maxima and minima of 
 horizontal intensity, corresponding to the maxima and min- 
 ima of the barometer, coinciding with noon and midnight, 
 morning and evening. In the transfers of force to preserve 
 the equilibrium of motion, the current would be the strongest 
 and the weakest at the points indicated by the correspond- 
 ing degrees of magnetic intensity ; at those parts the barom- 
 eter indicates the greatest change of level, which causes this 
 transfer of the force of rotation. 
 
 Again ; there is another manifestation of the need of more 
 and of less force at these opposite points of the earth, from 
 the differing degrees of the intensity of the tension of vapor. 
 Without any known cause, water at certain times passes into 
 vapor, and at others the vapor condenses under the same de- 
 gree of temperature. Besides the occasional and irregular 
 exhibitions of this phenomenon, there are also periodic alter- 
 nations, corresponding with the hour of the day or night. 
 The tension of vapor has also its two maxima and minima, 
 corresponding to those of the barometer and the compass. We 
 believe that this alternation is governed by the need of more 
 or less force of rotation of the several parts of the earth. 
 When force is required the vapor condenses, when it is 
 super-supplied, the water passes into vapor. We have re- 
 peatedly referred to this as one of the means by which the 
 equilibrium of motion is maintained. At first sight, the 
 influence of this alternate vaporization and condensation may 
 appear of little value ; but on the great scale of nature's 
 works, with the wide expanse of the surface waters of our 
 globe, it is indeed a vast agency. It has been supposed that 
 vaporization and condensation were determined directly or 
 indirectly by temperature ; but how can this be when vapor 
 is formed alike under the vertical sun of the tropics and from 
 
240 OUTLINES OF A SYSTEM OF 
 
 the frozen oceans of the poles, snow and ice, as well as the 
 warmest surface water, throwing off vapor which condenses at 
 times in all altitudes, and under every degree of sensible heat. 
 
 The temperature, positive or relative, produced by the 
 sun's rays, appears altogether insufficient as the direct or 
 indirect cause of the passage of the currents of force. It 
 cannot explain the maxima and minima of the barometer, of 
 the needle and of the tension of vapor, any more satisfacto- 
 rily than it could explain the two daily maxima and minima 
 of the tides. The sun's influence changes the temperature 
 of the earth only a few feet beneath its surface, and 
 the temperature varies according to elevation ; yet the 
 barometer, whether suspended over sunny plains or carried 
 to the summits of snow-clad mountains, notes equally the 
 diurnal changes ; and the needle in caves or mines, where 
 the thermometer shows that the solar influence never pene- 
 trates, records the hourly increase or diminution of the 
 magnetic stream by which its motions are governed. Mag- 
 netic storms also pass over vast portions of the earth, disturb- 
 ing the regular action of the magnetic needle, whatever may 
 be its altitude of position or the surrounding temperature ; 
 and if the needle is affected all over the world thus simulta- 
 neously by magnetic storms, surely that which causes its 
 regular action has an equal range, a range far too vast 
 to owe its power to changes of temperature, which from 
 their nature are limited and local. If the perturbations of 
 the needle are world-wide, so is the cause of its normal 
 action. 
 
 Unquestionably all these phenomena, constituting the 
 threefold manifestation of the transfer of force, are connected 
 with heat, not with heat from solar influence, but with the 
 sensible heat evolved by the passage or readjustment of the 
 
MECHANICAL PHILOSOPHY. 241 
 
 magnetic force. The temperature of soft iron is raised by 
 the process of infusing into it the magnetic power ; the heat 
 of the earth, below the surface at least, we believe is deter- 
 mined by its degree of magnetic force ; the magnetic poles 
 are the poles of extreme cold. Transfers cannot take place 
 without indicating that heat is another term for the force of 
 motion. " Terrestrial magnetism," says Humboldt, " stands 
 in most intimate relation with the internal as well as the ex- 
 ternal heat of our planet But the old explanation of 
 
 the horary variations by the progressive warming of the 
 earth by the rotation of the world, must be limited to its upper 
 surface." For the solar heat and the consequent changes 
 of temperature do not always reach the instruments which 
 alternate in their action. They are touched and moved by 
 the force of terrestrial magnetism, and their variations 
 record the changes in the intensity of its passing currents. 
 But, besides the transfer of force for the adjustment of 
 the rotary motion of the parts of the earth, which by the 
 oscillation of surface need the greater or the less degree, 
 there is another flow of the magnetic power to restore the 
 equilibrium of the earth's motion in her orbit of revolution. 
 They both affect the needle, combining to produce its varied 
 phenomena as well as the many meteorological changes 
 and vicissitudes, which present the action of the two causes in 
 various degrees of relative intensity. This globe requires 
 less of the force which impels her in her orbit at some parts 
 than at others. The point nearest the centre of revolution 
 describes an orbit eight thousand miles less in diameter than 
 the point which is the most remote, and generally one hemi- 
 sphere needs less of the force of motion than the other. 
 The rotation of the earth continually changes the position of 
 every part in relation to the centre of the orbit. There is, 
 21 
 
242 OUTLINES OF A SYSTEM OF 
 
 therefore, a constant, unremitting passage of force from one 
 part to the other, from one hemisphere to the opposite. 
 This which for the want of a better name we call the spare 
 force of revolution, we consider as the motive power of the 
 tides, as the impulse which causes the oscillation of the 
 great deep. 
 
 That there is this passage of electrical or magnetic force 
 around the globe is acknowledged ; and it seems evident 
 that it cannot be caused by the progressive warming of the 
 surface of the earth. If we are right in our conceptions of 
 the nature of force, a flow must be produced by the unequal 
 orbits described by the different parts of the earth, as they 
 are more or less distant from the centre of revolution. 
 This inequality appears to us sufficient to produce a transfer 
 that would account for the results which we impute to it ; 
 for there are instruments of such delicacy, as to detect a 
 variation of one forty-thousandth part of the magnetic inten- 
 sity, and surely nature would register in her phenomena the 
 differences in the degree of required force in orbits which 
 vary eight thousand miles in diameter. 
 
 There is another consideration which supports our belief 
 in the reality of this transfer of force. It is, if we may be 
 allowed the expression, the necessity of a life-giving circula- 
 tion, to impart to the face of nature its ever-varying beauty, 
 to produce those changes and vicissitudes which minister to 
 the enjoyment of life, and to create that ceaseless activity of 
 the elements which brings the world into sympathy with the 
 activity of living beings. Without this it would seem as if 
 all things would harden into monotony, and the power now 
 so fully exhibited in exciting and controlling the elements, 
 would be hidden by the dull, unvarying uniformity of its 
 action. We live in a world of change, but of change so lim- 
 
MECHANICAL PHILOSOPHY. 248 
 
 ited that the storm only heightens the enjoyment of the calm, 
 while it has power and beauty of its own, of change so 
 limited, that instead of manifesting chance, it unfolds de- 
 sign, the cycle of vicissitudes showing the steadfastness 
 of the Hand which governs them. 
 
 Our belief in the necessity of this constant transfer of 
 force is further supported by considerations drawn from the 
 arrangements, by which activity of motion is produced in the 
 other planets belonging to the solar system. The strength 
 of this flow of force is governed, not only by the diameter of. 
 the sphere, but also by the proportion which this diameter 
 bears to the diameter of the orbit. That each world may 
 have a sufficient current of force circulating through its 
 several parts to produce the necessary alternations, and yet 
 these alternations be kept within such bounds, that life and 
 the enjoyment of life may be secure, the diameters of the 
 planets increase as their orbits enlarge, and by the addition 
 of satellites, and by the increased number of these attendant 
 spheres, as well as by the wider sweep of their orbits, the 
 extreme points of each local system are more widely sepa- 
 rated as their distance from the centre increases, and an 
 equality in the transfers of force is maintained among them 
 all. This is the case with all the planets, except the sys- 
 tem of smaller spheres between the Earth and Jupiter. The 
 Asteroids have a greater eccentricity than the other planets, 
 and by the greater inclination of their orbits revolve in a 
 different plane, which may perhaps stand in the place of the 
 greater diameter. Were Jupiter placed next the Sun, the 
 wide distance between its extreme parts would bear too great 
 a proportion to its distance from the centre of its orbit. 
 The different degrees of force needed by the parts at the 
 outer and inner circumference of the orbit, would cause too 
 
244 OUTLINES OF A SYSTEM OF 
 
 rapid transfers ; while Saturn, at his distance, can bear the 
 enlargement of diameter caused by his rings ; and perhaps 
 in far-off Uranus the retrograde movements of his satellites 
 gives the required inequality. Nor can we fail to remem- 
 ber, that the outermost planets have the greatest velocity of 
 rotation. 
 
 Returning to the consideration of our own planet, we find 
 not only the transfer of force which is due to her diameter, 
 but also those variations of its intensity which proceed from 
 , eccentricity of orbit, and from the action of her satellite. 
 The motion of the earth in her orbit is not of uniform velo- 
 city, nor does her distance from the sun always remain the 
 same. Hence the increase and diminution of the transfer 
 of force is dependent on the season of the year ; hence has 
 the needle its two annual maxima and minima ; hence the 
 yearly barometrical changes, and the different degrees of 
 the tension of vapor. The maxima and minima of the year 
 correspond to summer and winter, spring and autumn, as 
 those of the day to noon and midnight, and morning and 
 evening. Thus " all things are double one against another, 
 and He hath made nothing imperfect. One thing estab- 
 lisheth the good of another." 
 
 There can be no independent change of motion in any 
 mass or any sphere. The force which one receives another 
 surrenders. All things therefore move sympathetically, 
 there is no isolation in any part of the universe. The 
 spheres move in unison, as if connected, (as the idea has 
 been expressed by another,) by elastic material ties. Dis- 
 believing altogether in the attractive and repulsive power of 
 matter, we regard the universe as one great whole, its 
 separation into parts in man's mind being only because he 
 must divide in order that he may comprehend. 
 
MECHANICAL PHILOSOPHY. 245 
 
 If the heavenly bodies generally move thus in sympathy, 
 if the vibration of the more distant stirs the force that gives 
 the complementary oscillation to the others, how much 
 greater the mutual influence between planets and their 
 satellites, whose relations seem designed to increase and to 
 vary the strength of the life-giving flow of force ! 
 
 The relation of the moon to the earth is not thus intimate 
 because of her nearness of position only. We regard the 
 moon as a part of, as pertaining to, this globe ; we consider 
 them as together constituting one member of the solar sys- 
 tem, revolving together around their common centre. The 
 moon is not an independent mass wrapped up in herself by 
 an individual rotation, as if a separate value were included 
 within her own diameter. Her secondary movement is 
 round the earth as her centre. It is true, as astronomy 
 asserts, that, in passing round the earth, she turns in relation 
 to a point in space. So does every mountain on the face of 
 the earth. Mont Blanc turns in relation to space once for 
 every diurnal revolution of the earth, otherwise its base would 
 not rest on the earth, and its summit point continually from 
 it. So the moon, because she turns in relation to space, 
 keeps, her libration excepted, the same hemisphere 
 always directed towards this globe. We repeat the idea ; 
 she does not by an independent rotation wrap up an inde- 
 pendent value in her diameter. 
 
 Besides, in the associated motion of the earth and moon 
 around their common centre, there is between them a point 
 of equilibrium which describes the true ellipse of 'their com- 
 mon orbit. This point of space, which would be the true 
 position were the masses united, is near the actual line of 
 the motion of both at the moon's quadratures ; at the new 
 and full moon they are both at the greatest distance from 
 
 21* 
 
246 OUTLINES OF A SYSTEM OF 
 
 the mean orbit. Hence come the monthly periodical 
 changes of the earth's motion, and with these changes the 
 periodical increase and diminution of the flow offeree, the 
 increased or diminished spare force of revolution, which 
 records itself in the greater or less flow of the tides, and in 
 the host of connected phenomena. 
 
 The maxima and minima of the tides take place after the 
 new and full moon, and after the quadratures. If the cause 
 of the increase and diminution of the current of force is the 
 oscillatory motion of the earth in her orbit, the onward move- 
 ment of the vibration would continue after the cause had 
 passed its maximum ; the motion of the earth would go on, and 
 its greatest aberration would be some two or three days after 
 the culminating point of the satellite which determined the 
 range of the perturbation. The extreme point of all connected 
 phenomena thus advances beyond the exciting cause. In 
 the extreme of the oscillation of the surface of the earth, its 
 opposite expansions and contractions stretch beyond the 
 normal hour. In the triple manifestation of the flow of force 
 by the barometer, needle, and tension of vapor, the highest 
 and the lowest range are not at noon and midnight, morning 
 and evening, but at later hours. There can be in the econ- 
 omy of nature no sudden suspension of the motion of large 
 masses. The transfer of force which accelerates or retards 
 is a gradual process. No sphere could withstand a sudden 
 change in the force which moves it ; and we love to bring 
 to mind the ease and elasticity of the motion of worlds, free 
 to swerve in their own diameters and to bend in their orbits, 
 yet every change having the safeguard of limit, the compen- 
 sation of mutual adjustments. We see in the very ellipti- 
 cal form of the orbits of the planets the means of insuring 
 this ease and freedom of motion. They are not bound in 
 
MECHANICAL PHILOSOPHY. 247 
 
 rigid circles, in which, by the fluctuations and transfers of 
 force, the time of rotation and revolution would be increased 
 or diminished, and the harmony of their movements be 
 broken up. The application or withdrawal of force would, 
 as it were, break a circle, and the planet would suddenly 
 fall to or from the centre ; while the ellipse is like an elastic 
 spring. The elliptical orbit can approach nearer to or recede 
 farther from the circle, and without a change of the major 
 axis the motion can be quickened or retarded in different 
 parts of the orbit, yet the period of the circuit be forever 
 the same. 
 
 But to return : that there are two tidal elevations and 
 two tidal depressions of the ocean waters, is known from the 
 diurnal ebb and flow on the coast. How are these waves 
 lifted up ? In what manner are these alternate elevations 
 and depressions of the great deep produced ? 
 
 We will suppose that there is not an alternate rise and 
 fall, but that the elevation is permanent, and is propagated 
 round the world. This hypothesis is inadmissible ; for the 
 uplifted waters would rush along with a speed equal to the 
 diurnal motion of the earth, and would overwhelm the land. 
 We will suppose that the elevation is not permanent, but 
 caused by a horizontal flow of water, by currents heaping 
 up the tidal wave. This is liable to the same objection, and 
 such currents could not be formed without exhibiting their 
 intense power. Only one other supposition can be made, 
 the water is lifted vertically, gradually raising itself up from 
 its bed and then again subsiding to rest. This also is inad- 
 missible ; for, were the waters thus raised without horizontal 
 currents, there must needs be a vacuum between the waters 
 and the bottom of the sea. We cannot believe that to form 
 
248 OUTLINES OF A SYSTEM OF 
 
 the tidal wave the waters flow horizontally round the earth, 
 or that they rise vertically from their resting place. 
 
 That which elevates the waters also elevates the earth on 
 which they rest. It is the enlargement of the globe at equi- 
 distant points, and its contraction at the intermediate points, 
 which rounds upward and curves downward the surface of 
 the ocean. This is the reason why no elevation is noticed in 
 inland seas and lakes, and why the tidal wave never mani- 
 fests itself on the sea-coast, the perceived phenomena being 
 simply the consequent ebb and flow of the surface water ; 
 for, as sea and land rise together, there is no gauge to mark 
 the expansion and contraction of the globe. Nor does the 
 curved surface of the ocean away from the land give the 
 surface flow. Like minor waves rising by the possession of 
 the due degree of force for the level to which they ascend, 
 the waters are at the true level corresponding to their 
 present force. The comparatively non-conducting land does 
 not give out the required force, and near the land the un- 
 supported waters establish the surface flow, and the more 
 land-locked the waters of the ocean, as in bays and chan- 
 nels, the greater is this flow. In the Bay of Fundy the rise 
 of the isolated waters is more than sixty feet, while the tide is 
 hardly perceptible on the shores of the broad Pacific. The 
 condition of oscillation is that the fall shall furnish the force 
 for the rise. In the great vibration of the waters, the fall- 
 ing must transfer to the rising water its needed support ; if, 
 therefore, the connection be in part cut off, if there inter- 
 vene a barrier, the force for support at the higher level 
 may not be furnished. From this may perhaps come the 
 horizontal flow. We present the idea for consideration, as 
 one that may account for the known facts. 
 
MECHANICAL PHILOSOPHY. . 249 
 
 The tidal wave must rise at every half rotation of the 
 earth, and the tidal depression must take place at the inter- 
 mediate equi-distant hour. The time cannot change ; this 
 oscillation, being determined by the rotation of the globe, 
 must coincide with the time of rotation. But the tidal flow, 
 though caused by this alternation, is an independent oscilla- 
 tion. It is caused by it ; but its movement is in different 
 time and of a different nature. One is a horizontal flow of 
 water for many miles, the other, a vertical rise measured 
 by feet. The one lags behind the other. They may be 
 compared to two unequal pendulums, the longer impelled 
 into vibration by the motion of the shorter, and their lengths 
 bearing such a proportion that after a fixed number of beats, 
 the motion becomes at regularly returning periods coinci- 
 dent in time. 
 
 To present a theory of the tides with minute exactness of 
 detail, would require the labor of years exclusively devoted 
 to the subject. We give the thoughts that have presented 
 themselves to our mind, without an elaborate analysis of 
 all the connected parts. We feel convinced that we have 
 pointed in the direction of their cause, and that the con- 
 nection of such a vast array of phenomena with the transfers 
 of force, caused by the unequal orbits of the rotation and 
 revolution of the several parts of the earth, proves that there 
 is the spare force of rotation and revolution in constant diffu- 
 sion, and that the earth, neither within her circumference 
 nor in her orbit, is held in the rigid bonds of gravitation, 
 but that an incessant and periodical oscillation is the life of 
 the universe. 
 
 Before we leave this chapter, which we have devoted to 
 the subject of the tides, we would once again recur to the 
 opinion we expressed, that there are in all oscillatory move- 
 
250 OUTLINES OF A SYSTEM OF 
 
 ments two conditions of the undulation, one, the impulse 
 or cause ; the other, the equipoise or balance, to receive 
 the impulse. Thus, in the oscillations of the great tidal 
 waves, we have for the impulse the transferable force of the 
 earth's revolution in her orbit, passing from point to point 
 in self-adjusting distribution, according as successively one 
 hemisphere may require more, and the other hemisphere 
 less, while the act of oscillation is the reception and transfer 
 by the crest and valley of the wave of the rotary force of 
 the world ; the one receiving the more as it rises, the other 
 imparting the more as it falls. Here, then, is a meeting 
 point of these two forces of rotation and revolution ; here 
 they join in one movement ; here is the place of inter- 
 mingling, of intercommunication, so that the excess of the 
 one can supply the lack of the other, and a perfect equi- 
 poise be established for the preservation of the harmony of 
 these great movements. 
 
 Thus is presented to the mind, instead of two isolated in- 
 dependent forces, the one for revolution, the other for rota- 
 tion, one majestic power, now divided according to the need 
 of motion, now commingling in some common movement. 
 Thus harmonious is nature, thus perfect in action is the 
 creating thought of God, a complete whole, in which even 
 -excess and defect, if they can occur, most perfectly balance 
 each other. 
 
 We have no sympathy with theories by which the world 
 is whirled about " with the dust of its own grinding," 
 or its energy is impaired by the friction of its own 
 action. We read such passages as the one we now quote 
 with feelings of revulsion, though it is not unusual language : 
 " Though we cannot by any stretch of the imagination em- 
 brace the period of the duration of the system, the conclu- 
 
MECHANICAL PHILOSOPHY. 251 
 
 sion still forces itself on the mind that at last it must end, 
 that one by one the planets," by the action of gravitation, 
 " must be lost in the sun, the sun itself perhaps be merged 
 in other suns, to contribute by the immensity of its attrac- 
 tion to the destruction of other systems ; that such will be 
 the inevitable effects is admitted ; but no inhabitant will 
 witness the catastrophe, for long before that event our race 
 will have been destroyed by the heat consequent on the 
 reduction of the orbit of the earth." 
 
 Distrust all theories which involve the gradual construc- 
 tion, or the gradual wearing out of the universe. It caine 
 when God willed, perfect at the very first ; it will continue 
 without sign of weakness or mark of decay so long as He 
 may determine, unworn and unimpaired, until He decrees 
 its end, when it shall have fulfilled His august design. 
 Change, apparent to us, is the life-giving stamp of per- 
 petuity. 
 
 " The world's unwithered countenance 
 Is bright as at creation's day." 
 
 There is a wide-spread belief that one of the planets of 
 the solar system has been broken, that the Asteroids are 
 the fragments of that shattered globe. This idea meets us 
 everywhere. It is expressed in standard books on astrono- 
 my, and in the rudhnental treatises designed for district 
 schools. What are the facts ? How did this idea originate ? 
 Long since, in the days of Kepler, it was observed that the 
 space between Mars and Jupiter was too extensive to be 
 untenanted. There was a break in the series of planets, 
 the proportional distance was not maintained. One planet 
 was wanted to give uniformity to the system, to perfect 
 the theory of relative distances. 
 
252 OUTLINES, ETC. 
 
 On the discovery of the first Asteroids, the facts could be 
 accommodated to the asserted law of distances, by the sup- 
 position that these small planets were parts of the one planet 
 which should have occupied the space between Mars and 
 Jupiter, that by some internal convulsion this planet was 
 rent asunder, or broken into pieces by a blow from some 
 erratic comet. This idea of a God-deserted world left to 
 the conflict of its own unrestrained forces, or wrongly placed 
 so as to be in the way of some other sphere, was entertained 
 for no other reason than that the supposition conformed the 
 system to Bode's law of planetary distances. 
 
 We would not venture to assert that worlds may not, by 
 omnipotent power, be recreated from the fragments of other 
 worlds, that the component parts of one sphere may not 
 be remodelled into other spheres. But we cannot, merely 
 to make good a mathematical calculation, entertain the idea 
 of a broken planet with the angular fragments of its crust 
 rounded into spheres by their own motion, revolving with 
 orbits arranged and places assigned by the action of their 
 centripetal and centrifugal forces. We need higher evi- 
 dence than Bode's law. We regard the asteroidal system, 
 the twelve or sixteen worlds revolving in their eccentric and 
 beautifully interlaced orbits, as another striking and won- 
 derful exhibition of the power and wisdom of Him who 
 formed them, this variety in unity, as another evidence of 
 design, this part of the heavens, as declaring afresh the 
 glory of God, and showing forth His handiwork. 
 
 
CHAPTER X. 
 
 ; * IN ORDER TO BIND TOGETHER FACTS, THEORY IS REQUISITE AS 
 WELL AS OBSERVATION, THE CORD AS WELL AS THE FAGOTS." 
 
 Whewell. 
 
 THE trade-winds, which are supposed by some to be an 
 aerial tide, caused by the attraction of the sun and moon, 
 oceanic currents, and some connected phenomena, now 
 claim our attention. 
 
 In a former chapter we expressed the belief that there is 
 a general law which governs the secondary movement of 
 the planets as well as their primary movement ; that is, 
 that there is a normal intensity of rotary motion, as well 
 as of the motion of revolution, belonging to every sphere, 
 and that the one is in a fixed ratio to the other. But as, 
 from its form, the intensity of rotation decreases from the 
 surface of a globe to its axis of motion, the law which 
 governs this movement must be related to the mean velo- 
 city, and not to the velocity of either extreme, to the 
 average speed, not to the motions of either the equatorial 
 or polar regions. 
 
 From this consideration, it is evident that while, in the 
 earth, for instance, there exists the due amount of rotary 
 force, this force is unequally distributed through its mass. 
 There are therefore portions which have a greater, and those 
 which have a less degree of force, than the mean force belong- 
 ing to the sphere. From the tendency of force to diffuse 
 
 22 
 
254 OUTLINES OF A SYSTEM OF 
 
 itself equally through every mass of matter, and from the 
 law that force is transferred from matter not susceptible of 
 motion by it to matter free to move, it follows, as force is 
 distributed through the earth according to the capacity for 
 motion, that air and water, to the extent in which they are 
 free to move independently of the more solid parts of the 
 earth, will have at the poles a motion greater than that of 
 the earth, and that these elements at the equator will have 
 less motion than the earth. 
 
 To illustrate these ideas : Were the earth a perfect 
 sphere, the mean surface velocity of rotation would be 
 found at the parallels of 45 north and south latitude, and, 
 as the earth is shaped, this determination is sufficiently 
 accurate for the purpose of general illustration. From this 
 line of mean velocity of surface rotation, towards the poles 
 as well as towards the equator, the rotary force exists in 
 varying degrees, according to the capacity for motion of the 
 different parts rotating as a united sphere. But the force 
 will not be thus distributed to that matter, which at the 
 equatorial or polar regions is not necessarily a rigorously 
 connected part of the earth, and which may have some ca- 
 pacity for motion independent of the motion of the sphere. 
 To the degree, therefore, in which air and water have the 
 power of independent motion, this motion will be found to 
 be related in its action to the mean surface velocity. 
 
 The atmosphere has this freedom of independent motion. 
 In its movement, therefore, it will be found that the mean 
 velocity of rotation, that with which the surface of the earth 
 moves at 45 latitude, will be the governing principle of its 
 independent motion. It will limit its eccentricity. The 
 winds, of course modified by other laws, will, as a general 
 principle, be related to this mean of rotation, and a reference 
 
MECHANICAL PHILOSOPHY. 255 
 
 to this fact will be found to dissipate some of the mysteries 
 of the movements of this free element. The atmosphere at 
 the north polar regions and the adjoining parts of the tem- 
 perate zone may have a force of motion more intense than the 
 the rotary force of those-portions of the earth. It will there- 
 fore move southward to increase the orbit of rotation, and 
 eastward because it moves faster than the earth. Hence the 
 prevalence of northwest winds in those regions. As we pro- 
 ceed southward through the mean of rotation, there is found 
 a great belt of variable winds. " What," says Mr. Guyot, 
 in reference to these regions, " is more fickle and capricious 
 than the winds ? They are symbols of changeableness itself." 
 At the equatorial regions, the atmosphere has less force of 
 rotation than the surface of the earth on which it rests ; of 
 course it has an apparent motion westward, from moving 
 more slowly than the earth. This wind also blows from the 
 centre northward and southward, thereby narrowing its 
 orbit of rotation, the converse of the action of the winds 
 from the poles, which move southward and northward to 
 widen the orbit of rotation. The easterly trade winds, by 
 the clouds and vapor which they transport, may present the 
 aspect of two zones, which seen from the moon might appear 
 like the belts of Jupiter, which planet, from its immense 
 diameter, and the consequently great velocity of surface 
 rotation, would most distinctly present the zones of retarded 
 and accelerated atmospheric motion. 
 
 We notice in the Annual of Science that Mr. Babinet 
 refers to retarded and accelerated rotation as the cause of 
 oceanic currents, believing " that the waters which flow 
 from the equator have an inclination to advance before the 
 motion of the earth, whilst those which come from the poles 
 have a tendency to remain behind the motion." But we 
 
256 OUTLINES OF A SYSTEM OF 
 
 apprehend that the reverse is the case. The waters follow 
 the laws of the atmosphere, and in their respective motions 
 there is that resemblance which indicates the same general 
 law. There is the great westerly current of the equatorial 
 regions corresponding to the trade winds. This extensive 
 current is deflected northward or southward, when it 
 strikes the eastern shores of the continents, and thus its 
 waters narrow their orbit of rotation by advancing towards 
 the poles. The currents flowing from the polar regions 
 widen their orbit by their advance towards the equator. 
 At the point of equilibrium of rotary force, about the 
 parallels of 45 north and south, all the oceanic currents 
 are turned to the eastward. Thus, in this general eastward 
 movement is found the compensation for the great westerly 
 current of the tropics, and the equilibrium of the waters is 
 preserved. 
 
 It has been supposed that the Gulf Stream, which is a 
 branch of the great westerly current arrested by land and 
 turned northward along the coast of the United States, is 
 deflected to the eastward in latitude 45 by the Banks, which 
 extends across the Atlantic Ocean in about this parallel. 
 We are inclined to the opinion that the same cause which 
 turns the current also forms the Banks.* This deflection is 
 not local and accidental. The current flowing by the east- 
 ern shores of Asia bends to the eastward at the same par- 
 
 * It is said that soundings extend from the Newfoundland Banks across 
 the Atlantic Ocean. We are also informed by an experienced navigator, 
 that in the summer season the Gulf Stream flows farther north before its 
 bend to the eastward than it does in the winter, thus following the sun as 
 do the trade-winds, these phenomena being related in their changes to 
 the changing angle of rotation and revolution, the extreme points of the 
 earth in their revolution following the direction of the sun as the centre of 
 revolution 
 
MECHANICAL PHILOSOPHY. 257 
 
 allel ; in the same degree of south latitude, a polar current 
 flowing northward bends to the eastward off the Cape of 
 Good Hope, while inshore close to the Cape, there is 
 a westerly current, these opposite currents running side 
 by side. The parallels of 45 are the dividing lines ; cur- 
 rents in lower latitudes flow westerly, in higher latitudes 
 flow north and south with an easterly tendency, until they 
 reach this point when they are turned eastward, the waters 
 on one side of the equilibrium of force having a greater, 
 and on the other side a less intenseness of velocity, than the 
 solid earth. The deviations from this general law are 
 caused by the position of the coasts against which the waters 
 impinge. In the map of currents presented in Guyot's 
 " Earth and Man," every arrow showing their direction 
 conforms to this statement. The moving elements, air and 
 water, in the polar regions move with greater, in the equa- 
 torial regions with less, than the mean force of the rotation 
 of the earth. Why, then, trace the cause of the trade 
 winds to the rarefaction of the atmosphere, caused by the 
 more intense action of the sun's rays within the tropics ? 
 Why speak of the attraction of the sun and moon as caus- 
 ing aerial tides, or oceanic currents, or tidal waves ? The 
 cause of these phenomena will be found on the earth, not in 
 the skies, in the changing force of the motion of our own 
 planet, not in the attractive power of other spheres. 
 
 Geology may find, in a reference to the parallels of mean 
 rotary velocity, some help in the investigation of the struc- 
 tural changes of the earth. The erratic drift of boulders and 
 diluvium is spread over the frigid zone and over the north- 
 erly parts of the temperate zone of the northern hemisphere. 
 This dispersion of drift, we believe, was simultaneous. The 
 
 22* 
 
258 OUTLINES OF A SYSTEM OF 
 
 torrent rushed from the polar region southward, with an 
 inclination eastward. Its southerly bounds are about the 
 parallel of 45. Again ; the range of the drift of icebergs 
 seems to be determined by their equilibrium parallels. The 
 mean temperature of the earth at the poles is said to be 
 about 10 of Fahrenheit ; and about two or three degrees 
 below zero at the two poles of maximum cold, twelve degrees 
 distant from the poles of the earth's axis. The Arctic and 
 Antarctic Oceans are frozen to a very great depth, and 
 " during eight months of the year a continuous body of ice 
 extends round the poles of maximum cold, occupying a sort 
 of elliptical area of above four thousand miles of diameter." 
 Icebergs are detached from the margin of this frozen zone 
 at certain seasons. By a beautiful provision of nature, ice 
 cooled to a certain degree changes its character, and from 
 being a non-conductor becomes a conductor of force ; at 
 one time, as if it were a mantle spread over the earth and 
 sea, it confines the heat until the extreme is beyond the 
 limit which nature has assigned ; it then is no longer a bar- 
 rier to the required adjustment, and perhaps by this very 
 means, some transfer of force rends the masses of icebergs 
 from the parent bed of ice, and urged by the present force 
 they move slowly but strongly towards the south or north, 
 undisturbed in their advance by storm or current, until by 
 the widened orbit of rotation the force which impelled them 
 from the poles is absorbed. Icebergs have been observed 
 thirteen miles in length, with perpendicular sides rising at 
 least one hundred feet above the surface of the sea ; but 
 they are found of all sizes and shapes drifting from the 
 frozen oceans. This drift of ice is arrested mainly at about 
 the parallels of 45, though solitary masses may occasionally 
 stray farther from the poles. The icebergs of the northern 
 
MECHANICAL PHILOSOPHY. 259 
 
 Atlantic, it is well known, collect at the Newfoundland 
 Banks as their resting place ; for there the mean of rotation 
 is obtained. 
 
 We notice the same limit to the drift on the land, to the 
 transportation of diluvium and boulders from the north. 
 The course of this mineral or earthy flow was southeasterly. 
 Its path is written down in grooves and striae, or diluvial 
 scratches, and by the smoothing of the northern sides of the 
 mountains. This current also arrested its flow when the 
 impelling force was reabsorbed in rotation by the extension 
 of its diurnal orbit. But the flow of earth and stone was 
 not like the slow movements of the icebergs ; by a sudden 
 rush, as it were, the mountain masses fell from the north. 
 The one is from the every-day action of force, the other 
 came from a readjustment of the earth's surface when it took 
 the form which fitted it for the home of man. The limit of 
 the drift is, however, the mean parallel of latitude, the 
 boulders and diluvium in northern Europe and northern 
 America being confined to the Arctic zone, and to the 
 northern part of the temperate zone. There is no easterly 
 or westerly drift, and none beyond the parallels of mean 
 latitude, or none of great extent arising from any widely 
 acting cause. 
 
 The diluvial scratches or striae marking the track of the 
 erratics from the north, are straight as a mathematical line. 
 They are found on the plains, on the northerly side, and 
 occasionally on the south side of mountains. By whatever 
 force they were moved, their course was not obstructed by 
 the inequalities over which they passed. They flowed on 
 as if without weight, now lightly, now heavily touching 
 the surface of the earth, ascending or descending as more 
 or less upborne by the impelling force. 
 
OUTLINES OF A SYSTEM OF 
 
 We believe that these mountain masses moved with in- 
 tense velocity, because the striae were so evenly grooved. No 
 current of water, nor iceberg floating in the current, nor 
 slide or glacier, could, from known causes move with sufficient 
 velocity to form these grooves. There would be irregulari- 
 ties of motion, depressions, gyrations. There is another proof 
 of the intense velocity of the motion of this flood of rocks. 
 The edges of the engraving rock, the angular points which 
 made the record, did not wear down or become blunted. 
 The only wear was on the tablet which received the im- 
 pression. The effect of great velocity is to preserve the 
 cohesion of the moving body or instrument. A tallow 
 candle, soft as it is, when discharged from a gun will pierce 
 through a pine board. Thus, by intense velocity alone could 
 the sharp angle of the rock making the impression be pre- 
 served. A slow motion of the mass would have worn the 
 engraving, as well as worn into the engraved rock, and 
 there could not have been an equal and even groove made 
 for any considerable distance. It has been remarked, that 
 the striae might have been caused by small stones, pebbles, 
 or sand, between the drifting boulders and the rocks over 
 which they moved. But such intervening substances would 
 have been crushed by the weight and friction. Smoothing 
 or polishing to some extent might have been produced by 
 this means, but not the straight furrow. 
 
 The vortex moulds (pot holes) to which we have before 
 referred, are circular cavities formed in the solid rock. 
 These generally contain a rounded stone or stones. On the 
 shores of Lake Superior are many of these cavities, and we 
 are told that " a stone in one of these might have weighed 
 fifty pounds. Some of the holes were three or four feet 
 deep, and as many in diameter ; some of them formed 
 
MECHANICAL PHILOSOPHY. 261 
 
 steps, the stone having worn down at one side of the hole, 
 and worked on horizontally awhile, and then downwards 
 
 again." 
 
 It has been surmised that these holes were worn into the 
 rock by the action of water on stones lodged in its crevices. 
 How could waves or running water make stationary whirl- 
 pools sufficient to whirl stones weighing fifty pounds penned 
 up in a narrow crevice ? Yet only a swift rotary motion 
 of the encaged stones could have worn these circular holes. 
 
 The motion required to produce these smoothly rounded 
 excavations could hardly be induced by the action of water. 
 The stones which formed them were probably arrested frag- 
 ments of the rushing flood of rocks. Their onward motion 
 being suspended, they would revolve with the same force 
 which before impelled them in a right line. They would 
 act as the arrested water of a current which exhausts its 
 force in the whirlpool ; and the existence of such excava- 
 tions seems to prove the intense velocity of the erratic drift. 
 
 We refer the period of the drift to the time of the great 
 change in the earth, which under the Providence of God 
 gave to it its present form. The moving mountains acted 
 upon by a force more than sufficient for rotation at their 
 position rushed southward, with an easterly inclination 
 widening their orbit, and moving with great velocity until 
 they arrived at the place of rest. 
 
 If this hypothesis be unsound, we believe that no theory, 
 which does not refer the rush to a current of the most intense 
 velocity, can explain the erratic drift. The respect we en- 
 tertain for those who seek to account for the facts of the 
 case from natural every-day causes, leads to hesitation, and 
 an analogous action on a smaller scale would confirm the 
 doubt ; but the record on the mountain-sides, the characters 
 
262 OUTLINES OF A SYSTEM OF 
 
 uneffaced by time impressed on the granite tablet, tell us of 
 a power no longer in operation, the action of which was 
 never observed by man. 
 
 Meteorology, if it may be allowed the name of science, 
 is a science of facts only. The meteorologist neither fore- 
 tells the weather, nor explains its phenomena. He sits, 
 patiently musing over storm and calm, tornado and zephyr, 
 fog and sunshine, the arctic cold and the torrid heat, look- 
 ing anon at the weathercock and the barometer, diligent in 
 recording variations, in a note-book already full of facts, 
 without a principle for their arrangement or explanation, 
 waiting for light to shine forth from his recorded observa- 
 tions upon the vicissitudes of the weather. 
 
 Yet there is nothing out of rule, beyond law, in these 
 apparently capricious changes. There is nothing in this 
 world of ours without a cause. The vane never turns but 
 by the operation of law altering the direction of the wind : 
 nor are the laws which govern the gale and the storm so 
 complicated and mysterious that there is no hope that the 
 mind may comprehend them. In olden times the heavenly 
 bodies presented to the observer nothing but involved, con- 
 fused, entangled movements ; yet the harmonious motion of 
 the spheres now ascertained gives to the astronomer his 
 deepest impression of the simple majesty of nature. If, a cen- 
 tury ago, it had been asserted that the time would come 
 when an almost instantaneous communication of thought 
 could be made to a friend a thousand miles off, and that 
 ideas would rush across continents with the speed of light- 
 ning, the expression of this now established fact would have 
 been deemed as wild and chimerical as it may seem at present 
 to say that future ages will so comprehend the laws of the 
 
MECHANICAL PHILOSOPHY. 263 
 
 elements, that to a very great and practically important 
 extent, the common weather will be predicted. Compare 
 any one science as it now is with its condition centuries 
 ago, and we hardly dare to limit its possible advance ; 
 for its progress is with accumulative velocity; discovery 
 does not exhaust the field ; every instance of successful 
 inquiry gives a vantage ground for greater results. Why 
 should we doubt ? " Even .ZEolus reigns by law," and 
 there is a control over the wildest elements. The law which 
 directs and restrains has not been promulgated, yet we wit- 
 ness the exercise of this control. In every truce which 
 terminates the struggle of the elements we recognize, 
 though we may not understand, the agency which effects it. 
 We quote the following from an article in the North 
 British Review : " For weeks and months the hourly varia- 
 tions [of heat] are of the most capricious and irregular 
 character ; the thermometer being sometimes stationary 
 for a day ; sometimes highest at midnight, and lowest at 
 noon. When we combine however the three hundred and 
 sixty-five observations at each hour, we find these hourly 
 means are the ordinates of a curve of beautiful regularity, 
 each of the four branches of which do not differ more than 
 a quarter of a degree of Fahrenheit from parabolas. The 
 varying temperature of a day, therefore, with all its 
 starts and irregularities, is controlled by a law as precise 
 and unerring as that which regulates the planetary motions. 
 But the other agencies of the atmosphere have not been 
 subjected to law. The wind and the rain, the hail and the 
 snow, the storm and the tempest, seem to have a will of 
 their own, and to triumph in mockery over the person and 
 property of man ; yet lawless as they appear, we shall some 
 time or other discover their haunts and disclose their 
 
OUTLINES OF A SYSTEM OF 
 
 secrets, even though we may never succeed in disarming 
 their fury and reducing their power. Even the hurricane 
 and tornado must yet submit to intellectual control, nor 
 shall the lightnings of heaven escape the analysis of genius. 
 . . . The time will come when the electric flash will be pre- 
 dicted with as much certainty as the occultation of a star, 
 or the emersion of a satellite from the shadow of its planet." 
 
 If in any department of inquiry there be not an even ad- 
 vance, if any science lags behind the others, there is great 
 reason to suspect that there is some radical defect in the 
 foundation-theories on which that science is based ; its culti- 
 vators should therefore go back and reexamine the first 
 principles on which it rests ; these readjusted with accu- 
 racy, they may be able to hold even way with their associ- 
 ated laborers in the much divided field of inquiry. 
 
 Upon a reexamination of first principles, it may be found 
 that the defect to be remedied in the department of mete- 
 orology is a mistaken idea of the extent of the influence of 
 the sun, both in relation to his attraction and to the heat 
 which emanates from him. It may be that the meteorolo- 
 gist goes too far from the field of action, for the cause of - 
 action, that he traces too much to foreign influence, too 
 little to domestic changes. 
 
 We quote from Sir John Herschell a description of the 
 supposed immense range of the sun's influence. " The 
 sun's rays are the ultimate source of almost every motion 
 which takes place on the surface of the globe. By its heat 
 are produced all winds, and the disturbances which result 
 in the changes of the electric condition of the atmosphere. 
 By these rays the waters of the sea are made to circulate 
 in vapor. By them are produced all the disturbances of 
 the chemical equilibrium. " And the paragraph concludes 
 
MECHANICAL PHILOSOPHY. 265 
 
 by assigning the phenomena of volcanic action, indirectly, 
 to the rays of the sun. Even more sweepingly are all 
 the changes of weather made dependent on solar influence. 
 We can hardly call to mind a single fact in this department 
 that is not explained by the vacua of the atmosphere, by 
 the unequal rarefaction of the air, produced by varying 
 temperatures. 
 
 The winds have but this one general cause assigned to 
 them ; and yet, if there are as great inequalities of density 
 in the atmosphere as are supposed to exist, it does not 
 clearly appear how these could create the winds, with their 
 intensity of force, long duration, and extensive range of 
 motion. An effect must be, in some degree at least, com- 
 mensurate with its cause. Motion cannot produce or pro- 
 long itself without cause. To fill vacua, to supply addi- 
 tional air for the restoration of equilibrium to the rarefied 
 parts of the atmosphere, would not require the rush of the 
 colder air for months, for weeks, for days, or even for hours. 
 The repairing and equalizing process, as the winds now blow, 
 would cause wider breaches of continuity than are repaired, 
 would create more void places than are filled. This 
 would undoubtedly be the case when the horizontal currents 
 of wind are greater than the upward-flowing current of 
 heated air, which is supposed to cause the wind. Vacua 
 are filled, and the equilibrium of the density of the atmo- 
 sphere is preserved, by the elasticity of the air. This acts, 
 as it were at once, almost instantaneously ; for the action 
 of elasticity is as rapid as the propagation of sound, while 
 gradually heated air ascends slowly, its place being sup- 
 plied as slowly. It can never create the intense motion of 
 a wind. 
 
 The colder air does not rush toward the heated air. 
 
 23 
 
266 OUTLINES OF A SYSTEM OF 
 
 Did it so rush, there would be established a violent wind, 
 regular and unintermitting, from the poles to the equator ; 
 there would be no wind, as there often is, speeding from the 
 sunny plains of the south, over snow-clad mountains, toward 
 the region of perpetual ice ; the trade winds would not 
 gently flow, spreading themselves toward the colder north 
 and south ; nor would the winds of the frigid zones incline 
 to the eastward. It is true, that there is a draft of air to 
 supply combustion, and that, whenever heated air ascends, 
 other air will move to maintain the equilibrium. The com- 
 parative density of the air, however, cannot account for the 
 geographical or periodic winds, or for local occasional 
 storms. It cannot explain either the direction, intensity, or 
 duration of the wind. Take, for an instance, the circular 
 motion of a tornado ; how can this movement be' induced by 
 a vacuum, or how can it restore the equilibrium of the 
 atmosphere ? 
 
 The idea has been recently entertained by scientific men, 
 that the trade winds arise from retarded rotation. It is 
 evident that the same cause inclines them northward or 
 southward, as, by thus narrowing the orbit of rotation, the 
 equilibrium of motion is restored, since the degree of present 
 force determines the orbit. Thus the winds from the frigid 
 zones flow to the east, moving with greater velocity than the 
 earth, and southwardly or northwardly to widen the circuit. 
 Thus the degree of force possessed by air compared with 
 the velocity of rotation of the part of the earth over which 
 it moves, is not the cause of the east and west winds only, 
 but it also determines the direction of the north and south 
 winds. The inequality of force, which thus gives direction 
 and intensity to the permanent geographical winds, can be 
 traced directly to the differing degrees of rotary velocity 
 
MECHANICAL PHILOSOPHY. 267 
 
 of different parts of the globe ; and we hope to be success- 
 ful in tracing the inequality which gives rise to the variable 
 and occasional winds. 
 
 The land and sea breezes alternating with day and night, 
 are frequently cited as proof that the varying density of the 
 air, caused by differences of temperature, determines the 
 direction of the wind. We think that this alternation is an 
 illustration of the views which we present. By night a 
 greater force of revolution is required, by day a less, as 
 the part of the earth is turned from or towards the centre 
 of revolution. The regular land and sea breezes are most 
 uniform and most active between the tropics, where day and 
 night make the greatest difference in the orbit of revo- 
 lution. These changes of the orbit are accompanied by 
 a transfer 6f force, and, of course, from the different con- 
 ducting powers of land and water land and sea breezes 
 would ensue. 
 
 The monsoons are periodic winds, which in some regions 
 blow regularly for a part of the year from the sea land- 
 ward, and at the opposite season blow from the land toward 
 the sea. In the regions where they occur, for a part of the 
 year the meridian sun is vertical over the land, and for a part 
 of the year it is vertical over the water. This is the con- 
 dition of these periodical alternations. The changing posi- 
 tion of the sun indicates that the earth's axis of rotation has 
 changed its position in relation to the centre of her orbit. 
 Of course the angle which rotation makes with revolution 
 has also changed, and, where monsoons occur, the extremes 
 of revolution periodically pass from the ocean to the land, 
 and from the land to the ocean. The change of the position 
 of the sun, north and south of the equator, causes, or 
 rather, denotes the change of the flow of the spare force of 
 
268 OUTLINES OF A SYSTEM OF 
 
 revolution which moves the elements. This determines the 
 monsoons. The trade winds also, in some degree, follow 
 the course of the sun ; in our latitudes the northwest winds 
 are most frequent and violent in the winter season ; the 
 Gulf Stream in summer runs further north before it bends 
 to the eastward. All the phenomena thus " following the 
 sun," and supposed to result from the influence of his rajs, 
 and the consequent inequalities of temperature, can thus be 
 traced to the changes of relative motion of different portions 
 of the globe, which alter the direction of the currents of 
 force, and consequently of the moving elements, air and 
 water. The position of the sun indicates these changes, 
 but neither his comparative distance, nor the comparative 
 directness or obliquity of his rays produces them. As the 
 hands of a clock indicate his position, so does his position 
 indicate the changes of the motion of the earth, and the 
 changing orbits of revolution and rotation of the several 
 parts of the globe. From these changes, and from the con- 
 sequent changes of the flow of force, come the movements 
 of the elements which give us the variations of meteoro- 
 logical phenomena. 
 
 We are fully aware that we have advanced many princi- 
 ples, which contradict the opinions of those who have devoted 
 themselves to the examination of these subjects. In meteo- 
 rological science, however, we do not feel that we are in the 
 opposition. It is confessedly an open field of investigation. 
 There is little or nothing definitely settled, and, if new 
 theories afford any clew to explanation, this result may 
 strengthen these theories as applied to subjects, which are 
 generally believed to be well explained by the theory of 
 universal gravitation. 
 
 A question has been recently proposed from a high 
 
MECHANICAL PHILOSOPHY. 269 
 
 source, " whether the gush of rain which usually follows 
 the detonation of a thunder storm is the effect or the cause 
 of the electric flash." Should there not be principles com- 
 petent to answer such inquiries, or rather principles, so 
 thoroughly settled, so accurately determined, as forever to 
 prevent such questions from being asked by scientific men ? 
 This is, however, but one of the many points on which no- 
 thing is distinctly known. What creates the progressive in- 
 crease of heat from the arctic to the torrid zones ? Can the 
 comparative obliquity of the sun's rays give a full and satis- 
 factory explanation ? Is there not a source of heat in the 
 earth, independent of the rays of the sun ? What is the 
 cause of the varying degrees of humidity in the atmo- 
 sphere ? Why does water change to vapor more rapidly at 
 one time than at another ? Why do the vapor wreaths now 
 hang over the surface of the earth, and now float aloft 
 as clouds ? Whence the cirrus, half-illuminated clouds ? 
 Why are the magnetic poles the poles of maximum cold ? 
 Why do the curves of equal temperature have for their 
 poles the poles of revolution ? All these phenomena are 
 surely not caused by the inequality of the sun's rays, their 
 varying obliquity, and the consequently irregular density of 
 the atmosphere. 
 
 In the last chapter we alluded to the many provisions, 
 creating the transfer of force, from which proceed the life- 
 giving alternations of the world. One of these provisions 
 was the diameter considered in its proportion to the orbit 
 of revolution, and another, the velocity of rotation. In our 
 planet, the greatest diameter, giving the widest extreme of 
 the differing orbit of revolution of its opposite parts, and 
 the most intense rotation, is between the tropics, at the 
 equator. In that region consequently will occur the greatest 
 23* 
 
270 OUTLINES OF A SYSTEM OF 
 
 and most rapid transfers of force. Accordingly, we find this 
 indicated, not only by the needle and barometer shewing even 
 the hourly variations of the strength of the flow, but by the 
 greatest and most sudden alternations of all meteorological 
 phenomena. There are the most active volcanoes, the most 
 frequent convulsions of the earth and disturbances of the 
 electrical condition of the atmosphere, and the most violent 
 hurricanes. For one instance, at certain seasons, in some 
 places between the tropics, almost every day, some four hours 
 after the sun has attained the meridian, there is a thunder 
 storm, while so rare is this occurrence in the northern 
 regions, that a traveller mentions as a fact worthy of note, 
 that in Nova Zembla and Spitzbergen "it is sometimes 
 heard to thunder." Contrast the general meteorological phe- 
 nomena of the polar regions with those of the torrid zone. 
 They present the extremes of a habitable earth, and these 
 extremes, we believe, are caused by the inequality in the 
 degree of those transfers of force, which give both the peri- 
 odic and the occasional alternations of the elements ; and, in 
 tracing out the causes of meteorological phenomena, we are 
 led to look to these transfers of force. For instance, if we 
 would know what causes the gush of rain accompanying the 
 flash of lightning, we should consider that the cloud is 
 formed from water by the reception of force, that by its rapid 
 condensation force is given out suddenly in the flash of light- 
 ning, and that the condensed water falls at one and the same 
 time ; they are the different phases of the same act. 
 
 We regard the barometer, not as indicating the pressure 
 of a column of air over it, but as indicating the level of its 
 rotation, and we believe that its oscillations at the same ap- 
 parent altitude mark the rising and falling surface of the 
 earth. By this view we have an explanation of the connec- 
 
MECHANICAL PHILOSOPHY. 271 
 
 tion of the changes of the height of the mercury with the 
 changes of the weather. 
 
 The rise and fall of the mercury denote the different 
 levels at which every part of the surface of the earth moves 
 in its diurnal round. By the rise of any portion of the 
 earth's crust more force for motion is required, by its fall 
 less is needed. In the one case force is given out or trans- 
 ferred from the earth ; in the other it is absorbed. A high 
 range of the barometer indicates a low surface and dry 
 weather ; a low range shows a high surface and wet weather. 
 A high surface therefore withdraws force from the vapor of 
 the air, and it condenses ; from the low surface force 
 escapes from the water in the form of vapor. To repeat 
 the idea, a high surface of rotation, indicated by the low 
 barometer, withdraws the sustaining force of vapor; a low. 
 surface, on the other hand, indicated by the high barometer, 
 supplies the force which gives tension to the vapor. The 
 act of withdrawing force by a rise of the earth would recon- 
 dense vapor ; the act of supplying force by a fall of the 
 earth would sustain the vapor in high-floating clouds. Thus 
 is explained the varying height at which the clouds float, now 
 enveloping the surface with fog and mist, and now rising 
 miles above us, with sharp and well defined outlines. 
 
 Water exists in the atmosphere in two states ; in the 
 one, at its greatest tension it is the unobserved humidity of 
 the air ; in the other, it is partially condensed in the form 
 of mist, or fog, or more properly vapor. The humidity of 
 the air is shown by the condensation that takes place in the 
 driest weather, on the outside of a vessel containing water 
 so much cooler than the atmosphere as to cause this conden- 
 sation. The dew-point is that degree of difference of 
 heat between the atmosphere and the earth, which is suffi- 
 
272 OUTLINES OF A SYSTEM OF 
 
 cient to cause the condensation of the humidity of the air 
 into dew. The formation of vapor and its recondensation 
 are not, however, the transfer of sensible heat only. They 
 are caused by the transfer of this heat, of electricity, of 
 galvanism, and of the magnetic fluid, all of which are but 
 phases of the dynamic power of the world, branches of 
 the great current of force by which the equilibrium of 
 motion is preserved. Thus dew is formed by night on 
 those parts of the earth which, being turned away from the 
 sun, require the greater force of revolution on account of 
 their enlarged orbit. It is not formed in cloudy weather, 
 because from local causes, as evinced by the very existence 
 of the clouds, the force which would be given out from the 
 formation of the dew is not required. Even the vapor 
 which rises from a water-fall gives to the air of its vicinity 
 an electrical state different from that of the adjacent atmo- 
 sphere. The electrometer proves that the electrical state 
 of the air changes with the condensation that causes the fall 
 of rain. " In fogs, and in the commencement of a fall 
 of snow," says Humboldt, " I have seen by a very Ions? 
 series of observations, the previously permanent positive 
 electricity rapidly .pass into the negative, both at the plains 
 of the colder zones and at great elevations between the 
 tropics." We know that the tension of vapor has its two 
 maxima and minima daily, which correspond to the maxima 
 and minima of the diurnal alternations of the surface of 
 the earth.* 
 
 * We have frequently alluded to the condensation of vapor by moun- 
 tains and high lands, for the reason that they require a greater force of rota- 
 tion. The fact is thus clearly expressed hy M. Guyot : " The mountain 
 chains are, then, the great condensers placed by nature, here and there 
 along the continents to rob the winds of their treasures, to act as reservoirs 
 
MECHANICAL PHILOSOPHY. 273 
 
 From this cause we have the different character of the two 
 opposite winds of our climate, the north-west, and the south- 
 east. The one is the polar current, in which the air comes 
 from the north, inclining to the east because of accelerated 
 rotation ; in the other the air comes from the south, with an 
 inclination to the west from retarded rotation. The one has 
 more, the other less, than the normal force ; the one by the 
 additional force increases the tension of vapor, the other by 
 the diminished force decreases it ; the one imparts force, 
 and water passes into vapor, the other withdraws force and 
 the vapor condenses ; the one usually gives dry and clear 
 weather, the other, fog, rain or snow. Of course the char- 
 acter of the wind is modified in some degree by its passage 
 over water or land, but, notwithstanding this modification, 
 the characteristic difference of these winds remains, and is 
 proved, not only by the different tension of vapor, but by 
 their contrary effects on the animal organization. The one is 
 an exhilarating, exciting wind ; the other is unelastic and 
 depressing.* 
 
 for the rain waters, and to distribute them afterwards, as they are needed 
 over the surrounding plains." . . . " But as we have .said the plateaus have 
 also a marked effect on the distribution of the rain waters. Their borders 
 act as mountains." .... 
 
 " The effect of the condensation in the supply of the force of rotation is 
 shown by the change it produces, in the character of the winds of the 
 tropics. The trade wind is from retarded rotation of the atmosphere. 
 The copious condensation of the moisture of the air into clouds, and of the 
 clouds into rain, at the rainy season, breaks up the trade winds. When 
 the trade wind blows with its accustomed regularity there is no condensa- 
 tion, 'the air is dry and the atmosphere cloudless.' The periodical rains 
 of the tropics follow the sun, or rather follow the extreme diameter of the 
 revolution of the earth." 
 
 * " This conflict of polar and equatorial winds," says M. Guyot, " oppo- 
 site in character and direction, gives to our climate one of its most char- 
 
274 OUTLINES OF A SYSTEM OF 
 
 How various are the considerations, how numerous are 
 the facts, which seem to support the position, that vaporization 
 and condensation are among the means of preserving the 
 equilibrium of motion ! The bright and clear sky, the dark 
 and lowering cloud, dry weather, fog and mist, the parched 
 earth, and the copious rains, these ever- varying alterna- 
 tions speak to us not of the changing heat of the sun only, 
 nor of a lighter or heavier atmosphere, but of the ever-pass- 
 ing currents of force, and through them of the varying level 
 of rotation as indicated by the barometer. Who can recall 
 the high electrical state of a clear day in midwinter or mid- 
 summer, the damp easterly winds of spring, or the murky 
 atmosphere of the dog-days, and not perceive that the ten- 
 sion of vapor is determined in some degree by the varying 
 motions of the earth, as she speeds in the different parts of 
 her orbit ? 
 
 We divide the winds into two classes, the normal winds 
 of the region where they occur, and the occasional winds 
 arising from local disturbances of the level of rotation. 
 At the extremes of rotary velocity, in the equatorial and 
 polar regions, the prevailing winds are of the former class. 
 There are the regular tropical winds, and the regular polar 
 currents of the northern and southern regions, arising from 
 the retarded or accelerated motion of the atmosphere. 
 Midway there is no prevailing atmospheric current, and the 
 winds arising from local changes appear fitful and capricious. 
 The regular winds are far-pervading, and blow in right lines 
 
 acteristic features, its changeableness, its extreme variety of temperature, 
 of dryness arid moisture, of fair weather and foul." . . . . " The polar 
 winds will prevail in a country and will endanger the crops by the pro- 
 longed dryness of the atmosphere, while further east or west, the trade 
 winds will spread fertility by beneficent rains." 
 
MECHANICAL PHILOSOPHY. 275 
 
 or in curves of wide radii ; the occasional cover a more lim- 
 ited range, moving in narrow circles. The one class has the 
 character of uniformity ; those of the other are storm winds. 
 Thus the hurricane of the tropics is usually a westerly wind ; 
 in our regions, and especially further north, the easterly 
 winds bring the most frequent tempests. Storms being in- 
 duced by sudden changes of level, the air moves with the 
 newly acquired force in a circle, and, as the depression 
 propagates its undulation, the circle advances. The cause 
 preceding the effect, and the change of level being the 
 cause, the barometer indicates the approaching tempest by 
 its sudden oscillation. Storms accompanying the prevailing 
 winds are occasioned by local disturbances accelerating 
 these winds. 
 
 We regard, then, the changes in the direction and inten- 
 sity of the winds, as determined by the transfers of force 
 from altered levels of rotation, and by changes in the position 
 of the earth. The theory which we present for consideration 
 will not only thus explain the great phenomena of the weather, 
 but also many of its apparently fitful changes. We have a 
 reason, for instance, for the want of permanency of fair 
 weather, when the wind of our climate lacks in, as it is called, 
 or comes round by the north to the westward after an east- 
 erly storm ; for this takes place by a local change of level, 
 not by the restoration of the normal wind as determined by 
 the season and by geographical position. We have also the 
 reason for the equinoctial storms, which result from a change 
 of the position of the earth relatively to the sun, the centre 
 of revolution, giving a new direction to the flow of force ; 
 and also for the changes of the weather connected with the 
 phases of the moon. The moon is the people's barometer ; 
 and we believe that it not only widens our local system and 
 
276 OUTLINES OF A SYSTEM OP 
 
 increases the flow of force, but periodically increases and 
 diminishes the intensity of the flow. Changes of weather 
 result from the transfers of force, and these are determined 
 by the motion of the world, as the moon and the earth swerve 
 sympathetically in their common orbit of revolution. 
 
 We pass to the consideration of other phenomena, which 
 seem to strengthen the position that the different degrees of 
 the tension of vapor, and the direction and intensity of the 
 winds, are determined by the degree of force relatively pos- 
 sessed by earth, water, and air, and that the tempest and 
 storm are but transfers to preserve the equilibrium of 
 motion, that they are not accidents, but the consequence 
 of those alternations which give to the elements their life 
 and activity, change within a fixed limit, creating the 
 " agreeable fitness " of all things in this beautiful home of 
 man. 
 
 There have been earthquakes in every part of the world, 
 and they are not rigorously confined to any season of the 
 year. They are, however, by far the most frequent in the 
 torrid zone, and at the commencement of the rainy season, 
 at the vernal and autumnal equinoxes, and at the changes of 
 the monsoons. "We trace them, then, chiefly in regions 
 where the transfers of force are the greatest, and at the 
 times of such changes in the earth's position as vary her 
 motion, and give alternations to the flow of force. An earth- 
 quake sometimes changes the level of rotation of a distant 
 part of the earth, in addition to the local convulsions which 
 it produces. After a violent earthquake in the island of 
 Sumatra, Darwin traced out, as a consequence of it, a sub- 
 sidence of land at a point six hundred miles distant. There 
 have been permanent elevations of a vast extent of coast by 
 this means. Earthquakes are not always preceded by 
 
MECHANICAL PHILOSOPHY. 277 
 
 atmospheric changes, but are invariably succeeded by rains, 
 even when rain is out of season where they occur. Very 
 little is known of the cause of earthquakes ; but we will quote 
 a remark of Pliny, which is somewhat in accordance with 
 our views. " They are because the elastic forces, concussive 
 by their tension, accumulate in the earth when they are 
 absent in the atmosphere ; " in other words, the force of 
 motion is too great for the orbit of rotation, and the earth 
 rises suddenly and convulsively. 
 
 Volcanoes are attended with the same phenomena as 
 earthquakes. In their periods of activity, beside the throw- 
 ing up of great volumes of lava and other substances, and 
 the local agitations produced, there is frequently an agitation 
 of the earth, which is perceived often at a very great dis- 
 tance. The eruption of a volcano is attended " with fierce 
 winds and deluging rains." Stromboli was considered as 
 the dwelling-place of -ZEolus, the regulator of the winds ; 
 and the fishermen on the coast were able to foretell the 
 weather by its eruptions, or by the premonitory symptoms 
 of an eruption. The connection between the eruption of 
 even a small volcano and the state of the barometer is 
 now generally acknowledged. The earth in the vicinity 
 changes its level before- and during the eruption. 
 
 The connection between the undulations of the surface of 
 the earth and the weather, thus indicated by the earthquake 
 and the volcano is not an exception to a general law. It 
 is, if we may be allowed the expression, the abnormal 
 action of the law ; it is a fact, standing as it were unnat- 
 urally, out of position, thereby distinctly showing the action 
 of a law otherwise hidden under the uniformity of its usual 
 routine. This known sympathy between the weather and 
 the change of level of a part of the earth's surface is not 
 
 24 
 
278 OUTLINES OF A SYSTEM OF 
 
 , 
 
 occasional or accidental. By these convulsions sudden 
 changes in the weather are produced ; but it is also varied 
 by more gentle alternations. It is by the transfers of force 
 that the rain falls and the winds blow. It is by the health- 
 giving readjustments of the force of motion that we have 
 the occasional storm ; it is by the equable flow of the life of 
 the world that we have the usual serenity of the face of 
 Nature. 
 
 The mean temperature of a season often changes over a 
 large portion of the earth. We have perhaps a cold sum- 
 mer, or a comparatively mild winter. This inequality 
 spreads as from a centre. As we go from this centre, the 
 excess or deficiency of heat decreases ; and, when we pass 
 the limit, the increase or diminution changes conversely, and 
 we have the opposite increasing alteration of the mean tem- 
 perature. This undulation of the curve of mean tempera- 
 ture moves mainly from north to south. How is this undu- 
 lation to be accounted for ? The sun shines as in former 
 seasons, nor can atmospheric pressure be tortured into a 
 reason. 
 
 We present another phenomenon connected with the trans- 
 mission of force, for a hasty examination. The aurora bo- 
 realis of our northern regions appears to be an arch or 
 circuit of the " magnetic force," spanning a portion of the 
 earth, as if conducting the flow from whence it abounds to 
 where it is needed without passing through the intermediate 
 parts. The shooting cylinders of rays have been compared 
 to the flame which arises in the closed circuit of the voltaic 
 pile between two points of carbon. Is it not a flame stretch- 
 ing between the surcharged and undercharged parts of the 
 earth or atmosphere ? That it is a passage of what is called 
 the galvanic fluid, we know ; for it disturbs the magnetic 
 
MECHANICAL PHILOSOPHY. 279 
 
 needle, which often points to the, corona of the arch. It 
 indicates a disturbed electric condition ; and, while the light- 
 ning in the electrical storm shows a sudden transfer of 
 force, the aurora represents a more gradual adjustment of the 
 equilibrium. It does not occur in the night-time only, but 
 its path may often be traced by day in a circle of half- 
 illuminated clouds. It is usually accompanied by a high 
 barometer and great tension of vapor, by all the phases of 
 motion which indicate more than the usually present force. 
 For this reason we consider it as a distribution of the mag- 
 netism of the polar regions, passing over an already well 
 supplied region. With us the aurora most frequently ap- 
 pears after an easterly wind has subsided, and a clear wind 
 from the northwest has begun to diffuse the spare force of 
 the more northerly regions. 
 
 The transfer of force shows itself often in a light which 
 follows its path, and attends its movements. There have 
 been luminous fogs ; there are often clouds half-illumin- 
 ated, shining not by reflected light, but by their own emana- 
 tions. Without any other assignable cause, whole nights, as 
 in Italy and the north of Germany in the year 1831, have 
 been so light that the smallest print could be read at mid- 
 night. What shall we say of the phosphorescence of the sea, 
 the waters of which, disturbed by the prow of a ship, with 
 a fresh wind and clear sky, are like waves of light ? The 
 presence of animalcules will not account for this ; for a certain 
 electrical state of the atmosphere always attends it. 
 
 But we must leave this, to us, interesting branch of our 
 inquiry. We know that we must have often erred in the 
 application of the principles which we present ; but errors of 
 application should not detract from the value of a general 
 principle. Our hope is, that in our illustrations we may 
 
280 OUTLINES OF A SYSTEM OF 
 
 have been so far successful as to give the necessary explan- 
 ations of our views, so that they may be examined and 
 tested, and, if found worthy, be applied by those who, from 
 years of devotion to scientific pursuits, are more competent to 
 work. Atmospheric changes seem capricious, as if without 
 the law ; but this must be in appearance only. The facts 
 which nature presents are never out of rule. As science ad- 
 vances, the discordant and conflicting phenomena decrease in 
 number ; the periodical, unvarying, regulated, become more 
 numerous ; order extends itself, and accident gradually 
 puts on the appearance of design. It appears as if order 
 was created by the sympathy of the mind with nature ; but 
 now and ever, whether we perceive it or not, a sovereign 
 law is completely and perfectly obeyed. The change is in 
 ourselves ; and the perfection of philosophy is this transfer 
 of the order without to order within, the regularity and 
 harmony of nature giving distinctness and definiteness to 
 thought. 
 
 Before we close this chapter, we will give the reasons why 
 we disbelieve altogether in the existence of the supposed 
 intense heat of the interior of our globe. This heat would 
 be a useless force, and, so far as the action of nature can be 
 traced out, there is found no unemployed or reserved dyna- 
 mic power. All force is in unremitting action. There is 
 no waste energy, none pent up, confined, laid by for 'ulte- 
 rior use. The sensible or diffusible heat of the planet 
 appears to come from the vital force constantly circulating 
 through every part of it, and through every element which 
 rests upon it, or envelops it. A flow of heat from the sun, 
 the centre of its revolution, warms its surface, and beneath 
 its crust the magnetism of the earth, from the decrease 
 of rotary force, gradually becomes sensible heat as we 
 
MECHANICAL PHILOSOPHY. 281 
 
 descend. The magnetic elements of any portion of the 
 globe may be calculated from the heat of that portion, and 
 conversely the distribution of the magnetic force may be 
 calculated from the distribution of heat. Force exists every- 
 where as it is required, and resolves itself into sensible heat 
 no further than by the transfers needed for readjust- 
 ments of equilibrium. The normal action of the needle is 
 from the steady flow of force, and its variations of intensity 
 are from the periodic or occasional variations in the current. 
 On the other hand, the supposition of intense internal fire 
 requires the belief of a permanent inequality, an abiding 
 want of equipoise.* 
 
 We shall be pointed to the earthquake and asked, whence 
 its power ? We reply, it is a sudden restoration of equili- 
 brium, proving that the globe does not bear even slight 
 irregularities, but frees itself of all superfluous power. In 
 relation to the volcano, we have the same answer ; and 
 further, the force or heat exhibited by the earthquake and 
 volcano is altogether insufficient, taking into consideration 
 the magnitude of the globe, to indicate that its interior is a 
 mass of liquid fire. 
 
 We shall be pointed to the crystalline structure of the 
 Plutonic rocks, as proof that these rocks were once fluid 
 from intense heat, and to the upturned strata of the globe, 
 to its distorted mountain ridges, as evidence that heat was 
 
 * The writer of a valuable scientific article in the fifth volume of the 
 North British Review, expresses a somewhat similar idea. He remarks, 
 " When we look at the system of isothermal curves surrounding the poles 
 of revolution, and mark their coincidence with the magnetic poles of the 
 earth, and their similarity to the isodynamical magnetic curves, we are 
 disposed to view so remarkable a phenomenon, as the result of a physical 
 condition of the earth itself, and produced by causes connected with its 
 magnetic, or galvanic, or chemical agencies." 
 24* 
 
282 OUTLINES 'OF A SYSTEM OF 
 
 necessarily the producing cause of the convulsion which up- 
 lifted them. Although we know that crystallization takes 
 place at times without sensible heat, by the magnetic power, 
 we are ready to admit that in the hands of God heat may 
 have been the instrument of re-creation ; but, because force 
 under this form may have been His means of action, it does 
 not follow that it now remains pent up in the bowels of the 
 earth. The same force under other forms of power may be 
 doing His will in the preservation of the globe which he fitted 
 for the home of man. 
 
 But how little of the interior of the earth is known ! Man 
 has penetrated a few feet only. The upraised mountain 
 which is supposed to indicate its deeper structure, may have 
 been changed by its elevation, and may not represent the 
 greater depth. We know nothing of the beds of the ocean, 
 nothing of the internal condition of the earth. Scientific 
 men in Europe are now disputing whether this globe is a 
 hollow sphere, or a solid mass, or whether its interior is com- 
 posed of molten fire. We venture to predict that the ulti- 
 mate decision will not be in favor of the latter supposition. 
 From analogy we believe in its perfect regularity of struc- 
 ture ; the distortions and bendings of its upper rocks may 
 be surface-changes only. 
 
 There can be nothing accidental in the position of any 
 portion of the earth ; and, when we recur to the fact, that 
 for hundreds of miles the extended quarries of rock preserve 
 one direction of dip, and one angle of stratification, when 
 we remember the order of the superposition of the various 
 strata all over the world, we cannot regard the form of the 
 earth as given to it by the accidental heaping together of 
 heterogeneous masses of mineral, convulsively commingled 
 from the bursting of its crust by the action of internal fire. 
 
MECHANICAL PHILOSOPHY. 283 
 
 Science with its present knowledge has ascertained a more 
 perfect order than chance explosions could produce. 
 
 In a previous chapter we alluded to the recently discov- 
 ered magnetic properties of crystals. The experimentalist 
 found that different crystals possess this virtue in varying 
 degrees, and that, when suspended by delicate threads of silk, 
 some point to the magnetic poles, and some to the poles of 
 the earth's axis, while some act as declination-needles. The 
 direction which the crystal takes is determined by the di- 
 rection of its natural cleavages. Is not this earth, as it 
 were, suspended and free to move under the impulse of 
 magnetic force ? Is not the very lay and dip of its mineral 
 body, the stratification of its framework of rock, so 
 arranged that the flow of force may guide and determine its 
 motion, as the minor stream of magnetic power influences 
 the direction of the crystal ? Its structure may have been 
 given to it to adapt it for its required movements, and what 
 appears to us as the accidental position of its parts, may be 
 as much induced by law as the symmetry of the brightest 
 gem. 
 
CHAPTER XI. 
 
 "IN ALL OTHER SCIENCES THE PROPOSITIONS THAT WE ATTEMPT TO 
 ESTABLISH EXPRESS FACTS REAL OR SUPPOSED ; IN MATHEMATICS 
 THE PROPOSITIONS THAT WE ATTEMPT TO DEMONSTRATE ONLY 
 ASSERT A CONNECTION BETWEEN CERTAIN SUPPOSITIONS AND 
 CERTAIN CONSEQUENCES." Stewart. 
 
 IT is supposed by many that the theory of universal grav- 
 itation has been mathematically demonstrated, and therefore 
 stands incontrovertible. These questions will be asked : is 
 not the mutual attraction of the heavenly bodies the very 
 basis of mathematical astronomy, by which the position of 
 every sphere is determined ; and does not observation confirm 
 the reasoning, and of course the theory on which the rea- 
 soning is founded ? 
 
 The hand of a clock may point to the time of noon, and 
 thus indicate the position of the sun> while neither the 
 movement of the wheels, nor the movement of the pendu- 
 lum which governs them, conforms in the least to the motions 
 of the sun. Thus mathematical reasoning may track out the 
 equable motions of the heavenly bodies, while neither the 
 theory on which the process is founded, nor the process 
 itself, in the least degree indicates the cause of the motion. 
 A mathematical process is at times even aided by fiction, 
 and is often successful when the theory on which it is based 
 is known to be the very opposite of truth. 
 
 Under the Ptolemaic theory the apparent motion of the 
 
MECHANICAL PHILOSOPHY. 285 
 
 heavenly bodies was considered the true and real movement. 
 The earth was then believed to be the motionless centre 
 around which the universe rolled. With this assumption 
 the mathematician could, with surprising exactness, project 
 eclipses, and predetermine the relative position of a sphere 
 at any given future time. With this obviously false theory 
 as the groundwork of calculation, results of great accuracy 
 were obtained. This idea has been thus clearly expressed : 
 " Now the truth is that this complicated and fantastic theory 
 of the heavens, [the Ptolemaic,] with its operose contriv- 
 ances of eccentric wheels, and circles riding on circles, and 
 which in point of fact is false from beginning to end, is just 
 as correct a basis for astronomical calculations, as the sim- 
 pler, more beautiful, and more truthful system of Coperni- 
 cus. The language of Mr. Whewell, whose authority on 
 a point like this, no one will dispute, is, ' As a system of cal- 
 culation it is not only good, but in many cases, no better 
 has been discovered. 7 7: 
 
 The character of the mathematical calculations, which 
 are relied upon to prove that the theory of gravitation is 
 applicable to the bodies composing the solar system, may be 
 learned by the following quotation from the History of the 
 Inductive Sciences : " The difficulty of doing what Newton 
 did may be judged of from what has already been stated, 
 that no one with his methods has yet been able to add any 
 thing to his labors ; few have undertaken to illustrate what 
 he has written, and no great number have understood it 
 throughout. The extreme complication of the forces, and 
 of the conditions under which they act, makes the subject 
 by far the most thorny walk of mathematics. It is neces- 
 sary to resolve the action into many elements, such as can 
 be separated ; to invent artifices for dealing with each of 
 
286 OUTLINES OF A SYSTEM OF 
 
 these, and then, to recompound the laws thus obtained, into 
 one common conception. The moon's motion, for instance, 
 cannot be conceived without comprehending a scheme more 
 complex than the Ptolemaic epicycles and eccentricities in 
 their worst form ; and the component parts of the system, 
 are not mere geometrical ideas requiring only a distinct 
 apprehension of relations of space to hold them securely ; 
 they are the foundation of mechanical notions, and require 
 to be grasped so that we can apply to them sound mechan- 
 ical reasonings. Newton's successors, in the next genera- 
 tion abandoned the hope of imitating him in this intense 
 mental effort ; they gave the subject over to the operation 
 of algebraic reasoning, in which symbols think for us with- 
 out our dwelling constantly on their meaning, and obtain 
 for us the consequences which result from the relations of 
 space and the laws of force, however complicated be the 
 conditions under which they are combined." 
 
 Again ; " if the mathematical calculations of the unmixed 
 effect of the central force required transcendent talents, 
 how much must the difficulty be increased when other influ- 
 ences prevented those first results from being accurately 
 verified, while the deviations from accuracy were far more 
 complex than the original action ! If it had not been that 
 these deviations, though surprisingly numerous and compli- 
 cated, were very small in their quantity, it would have been 
 impossible for the intellect of man to deal with the subject ; 
 as it was, the struggle with its difficulties is even now a mat- 
 ter of wonder." 
 
 " And even the possibility of doing what has been done, 
 depends on what we call accidental circumstances, the 
 smallness of inclination and eccentricities of the system, 
 and the like. If nature had not favored us in this way, 
 
MECHANICAL PHILOSOPHY. 287 
 
 La Grange used to say, there would have been an end of 
 geometry in this problem. " 
 
 With a full admission of the accuracy of the results of 
 mathematical reasoning as applied to astronomy, it does not 
 follow that the spheres attract each other. An aberration 
 or perturbation of the earth, calculated from the increased 
 nearness of the sun, may be correctly calculated, and yet 
 the aberration may not be occasioned by any attractive 
 power in the sun. The motion of the earth may be changed, 
 because of the greater force of motion relatively to the 
 diameter of her orbit. The navigator finds the position of 
 his ship by the aid of the imaginary lines of latitude and 
 longitude intersecting each other ; but it is not these lines 
 which give position to the ship. Thus may the astronomer 
 find the place and determine the motion of a planet by ima- 
 ginary forces, the one acting inward, the other outward; 
 but these forces do not give position to the star. His 
 calculation might be more difficult, yet no less certain, if in 
 the place of two conflicting forces he used as the basis of his 
 reasoning but one force giving directly the form of the orbit. 
 
 The arithmetical calculator takes for truth the simple 
 relations of numbers. He believes in his data intuitively ; 
 and he extends these, the more simple relations, to the more 
 complex ratios and values. The astronomical mathemati- 
 cian assumes that bodies fall by the attraction of the earth, 
 and he extends tne attraction of matter to the spheres. 
 This extension partakes not only of the uncertainty of the 
 premises, but also of the uncertainty which may arise from 
 errors of mathematical reasoning. The assumption may be 
 gratuitous, and the process, thus intricate and complicated, 
 may be defective. Uncertainty from two sources, there- 
 fore, attaches to his conclusions. The results of this math- 
 
288 OUTLINES OF A SYSTEM OF 
 
 ematical reasoning come not with the authority of the 
 multiplication table. There is a vast difference between 
 pure mathematics and the abstrusities of reasoning which 
 extend mere speculation, by symbols that think for the 
 calculator. The assertion that two and two are four, makes 
 a different impression on the mind from that made by the 
 calculations, by which the dynamical laws of nature are 
 mathematically handled. Number, quantity, ratio, consti- 
 tute the domain of mathematics. In these it is absolute, 
 while it is the aid, the coadjutor only, in natural philosophy. 
 
 We quote the following from Stewart's Philosophy: " In 
 pure mathematics when the truths we investigate are all 
 coexistent in point of time, it is universally allowed that one 
 proposition is said to be in consequence of another, only 
 with a reference to our established arrangements. Thus 
 all the properties of the circle might be as rigorously de- 
 duced from one general property of the curve, as from con- 
 siderations derived from the radii. But it does not follow 
 that all these arrangements would be equally convenient ; 
 on the contrary it is evidently useful and indeed necessary 
 to lead the mind as far as is practicable from what is sim- 
 ple to what is more complex. The misfortune is that it 
 seems impossible to carry this rule universally into execu- 
 tion, and accordingly in the most elegant geometrical trea- 
 tises which have yet appeared, instances occur in which 
 consequences are deduced from principles more complicated 
 than themselves." 
 
 Every one in the least acquainted with mathematical 
 astronomy is aware that its great burthen has been the 
 process of correction. Thus the mass of Jupiter, his 
 attractive value, has been calculated and recalculated ; and 
 is it wonderful that in all the changing results a value 
 
MECHANICAL PHILOSOPHY. 289 
 
 should at last be hit upon that would bring his influence 
 under the theory of gravitation ? The operation by which 
 such results are obtained, involves the process of integration, 
 " which cannot be performed in an immediate manner, since 
 the quantities to be operated upon depend upon the facts, 
 and thus require us to know the very thing which we have 
 to determine by the operation. The result must be got at 
 therefore by successive proximations. We must find a 
 quantity near the truth, and then by the help of this, 
 another, and so on." Whewell says, " The form in which 
 the question of the truth of the doctrine of universal gravi- 
 tation now offers itself to the mind of astronomers is this : 
 that it is taken for granted that it will account for the mo- 
 tion of the heavenly bodies, and the question is with what 
 supposed masses it will give the best account." This is the 
 same as if it were asserted that twenty plats of ground con- 
 tained an equal number of acres, and, this being taken for 
 granted, the surveyor's question is, what assumed angles of 
 each plat will best conform the theory to his calculations of 
 the areas ? 
 
 But if the mathematical process of thought could embrace 
 the laws of force and motion, could extend the law of 
 falling bodies to the mutual relations of the planets, there is 
 yet no determinate law under the theory of gravitation to 
 be carried up from the earth. The law of the uniformly 
 accelerated motion of a falling stone has no application what- 
 ever to the equable motion of the heavenly bodies, and the 
 law of uniformly accelerated motion is the only principle 
 which the fall of bodies to the earth has yet established. 
 
 The law that attraction is in direct proportion to the mass 
 of matter which attracts, and in inverse proportion to the 
 25 
 
290 OUTLINES OF A SYSTEM OF 
 
 square of its distance from that which it attracts, can never 
 be proved from the action of a falling body. Bodies falling 
 to the earth, without reference to the medium in which they 
 move, fall in the same time ; a heavy pendulum vibrates in 
 the same time as a light pendulum with the same arc ; the 
 world is so large in relation to falling masses, that the reci- 
 procal attraction cannot be observed, and all that is known 
 of the earth's attraction is, that all falling masses, whatever 
 be their quantity of matter or their distance, are drawn with 
 equal force. By the theory, indeed, there is an ounce 
 weight's difference between the strength of the earth's at- 
 traction for one ton at her surface, and her attractive force 
 for this ton a mile above her surface ; but this is too small a 
 diminution of attraction to be the subject of accurate expe- 
 riment. To test, therefore, the theory of attraction relatively 
 to mass and distance, we must go up from the earth to the 
 spheres. There again is another defeat ; for, though the 
 relative distances of the heavenly bodies can be calculated, 
 there is not one of them of which the mass, density, or at- 
 tractive power can ever be known ; and without this know- 
 ledge there is no proof that they do attract according to mass 
 and distance. They attract as much as they do attract ! 
 " It is by the means of the perturbations of the planets," 
 says an eminent astronomer, " as ascertained by observation, 
 and compared with theory, that we arrive at a knowledge of 
 the masses of those planets, which, having no satellites, offer 
 no other hold on them for that purpose." . . " The perturb- 
 ations of the satellites of Jupiter have led, and those of 
 Saturn will doubtless hereafter, lead to the proportion of 
 their masses to their primaries." In this view, all difficult- 
 ies are avoided ; the spheres do attract according to the 
 law of mass and distance, for the mass is of a changeable 
 
MECHANICAL PHILOSOPHY. 291 
 
 value to suit the theory of attraction. Thus, the earth's 
 diameter is, say eight thousand miles, the moon, say two 
 thousand miles ; the mass of the earth being one, the moon 
 to fit her for her attracting office, is placed at 0.125172. 
 Bulk and distance are of no consequence whatever ; for the 
 mass of any sphere is so fixed as to make all things conform to 
 a law, which is not indicated by experiment or accurate obser- 
 vation. But even now there are difficulties, and ever have 
 been. Says Herschell, " the curious and complicated effect 
 of perturbation has given more trouble to geometers than 
 any other part of the lunar theory. Newton himself had 
 succeeded in tracing that part of the motion of the apogee 
 which is due to the direct application of the radial force, 
 but finding it only half what observation assigns, he appears 
 to have abandoned the subject in despair. Nor when 
 resumed by his successors, did the inquiry for a very long 
 period assume a more promising aspect, and strong doubts 
 were excited whether this feature of the lunar motion could 
 be explained at all on the laio of gravitation" It was 
 afterwards settled by taking more properly into account the 
 tangential force. 
 
 There was, too, a difficulty with the secular acceleration of 
 the moon's mean motion, " which, like the great equation of 
 Jupiter and Saturn, had been long the subject of toilsome 
 investigation. Some were again on the point of declaring 
 the theory of gravitation inadequate to its explanation, and 
 others were for rejecting altogether the evidence on which 
 it rested." In this dilemma, La Place stepped in to rescue 
 astronomy from its reproach. There was a difficulty, too, in 
 some of the relative motions of Jupiter and Saturn, " at 
 one time too hastily regarded as almost subversive of the 
 doctrine of gravitation" 
 
292 OUTLINES OF A SYSTEM OF 
 
 Not many years ago doubts were entertained by the 
 German astronomers, whether the law of gravitation were 
 rigorously true with regard to the planetary bodies. Some 
 calculations showed that the attraction of Jupiter as mani- 
 fested by the perturbations of the small planets, Juno, Vesta, 
 and Pallas, was different from the attraction on his own 
 satellites. They inclined to the opinion that the attraction 
 of the spheres might be elective. But this was met by a 
 new determination of the mass of Jupiter by Mr. Airy. 
 
 One thing is certain, that it was a work of great time 
 and labor, so to arrange the masses of the spheres, and so 
 to construct the mathematical theory, that the perturbations 
 could be made to conform to the hypothesis of gravitation ; 
 and that now the mathematical theory is far in advance of 
 observation, bearing in a degree the same relation to per- 
 turbation, that the mathematical theory of the tides bears to 
 the observed facts of the tides. There is perhaps much to 
 cause the astronomer who believes in gravitation, to believe 
 also that perturbation is caused by mutual attraction ; and 
 yet these perturbations could not of themselves, apart from 
 theory, have led to the theory, nor can they prove the 
 theory of themselves, for the reason that the masses of the 
 spheres are determined by the theory itself. 
 
 We form the most definite idea of perturbation by the 
 analogy before alluded to, presented by a distinguished 
 astronomer : " The laws of perturbation will be indicated 
 by supposing all the spheres to be connected by imperfectly 
 elastic material ties. By their motion there would be a 
 forced vibration or oscillation communicated through the 
 whole system of worlds." Perturbation is periodic and 
 diffusible ; the amount of eccentricity is equally divided, 
 what has been called the " eccentricity fund " is the pro- 
 
MECHANICAL PHILOSOPH?. 293 
 
 perty of all in a certain fixed ratio. There is nothing erratic, 
 incidental, accidental about it. The periods of the sidereal 
 year of the earth will be the same after a thousand more 
 revolutions. The mean form of the orbit will never change. 
 It is independent of the number of worlds, and of the quantity 
 of matter that is or has been on either side of it. What- 
 ever be the tie of the worlds, astronomers should never have 
 applied to fixed and periodic changes the word " perturba- 
 tions." The word does not belong to the movement of 
 worlds, so exactly balanced by Infinite Wisdom. 
 
 In what other respect than as accounting for perturbation 
 is the theory of gravitation even remotely connected with the 
 movements of the heavenly bodies ? Not surely with their 
 motion. That gravitation gives motion to the planets has 
 never been assumed by those who invented the theory, nor 
 by any of the distinguished philosophers who have upheld it. 
 All acknowledge an original impulse of motion. It is sup- 
 posed that matter, when once set in motion, tends to move 
 onwards in a straight line with a uniform velocity forever. 
 This assumption that all motion is naturally in a straight 
 line, is, we believe, the foundation error; and it is 
 this assumption which necessitates the supposition of an 
 attractive force to give to the straight line its unnatural 
 curve. The assumption of this necessitates the suppo- 
 sition of the centrifugal force, to keep the planets from 
 falling inward when drawn by the attractive force. Now it 
 is found that the curvilinear motion of the planets can be 
 mathematically represented by the action of these two sup- 
 posed forces, the one, of gravitation, which constantly 
 deflects the straight line into a curve, the other, of repul- 
 sion, which prevents the planet from being too much de- 
 flected. From these, though they may be mere fictions, 
 
 25* 
 
294 OUTLINES OF A SYSTEM. OF 
 
 can be deduced mathematically the true motions. Of 
 course, this success of the mathematician does not in the 
 least prove the theory. 
 
 Whewell says, " many men of good intellectual culture 
 entertain in relation to gravitation vague and perplexed 
 ideas, which show very clearly that the acceptance of the 
 idea, is the result of traditional prejudice, not of rational 
 conviction." If the theory of gravitation be true, it is 
 indeed time that every educated man should have fixed and 
 definite ideas concerning it. It is not claimed for the the- 
 ory that this earth falls toward the sun as a stone falls to the 
 earth. Attraction is equipoised by the repelling force. It 
 is a statical force only. With the aid of its opposite force, 
 it preserves the earth's distance from the sun. It is thus 
 supposed only to determine the curve of the orbit ; and this 
 curve is modified somewhat by the attraction of other bodies. 
 This is the extent of all that can be claimed for gravitation 
 as acting in the solar system. 
 
 We have then this simple intelligible statement : the 
 impulse of the motion of the planets which, not modified, 
 would produce motion in a straight line, by the action of the 
 centripetal and centrifugal tendencies results in the curvi- 
 linear. The attractive force is entirely incompetent of itself 
 to give the orbit. It requires the supposition of an opposite 
 force of equal intensity. If we should begin with a belief 
 in the repulsive power of matter, this belief would require 
 also the belief of an opposite force of equal intensity. Each 
 fiction requires another fiction, the one destroying the 
 power of the other. They are useless. The planet with 
 them, or without them, moves by its own impulse of motion. 
 
 If the centrifugal force is the tendency of a planet to 
 assume a straight line of motion, the strength of this force 
 
MECHANICAL PHILOSOPHY. 295 
 
 must be determined by the strength of the impulse of mo- 
 tion. If the planet's force of motion is always of one degree 
 of intensity, so must be the centrifugal force. But a vary- 
 ing attractive force requires a varying centrifugal force. 
 The curve of the orbit demands an equal balance of repul- 
 sion and attraction. If the sun attract the more, centrifugal 
 force must repel the more, and if by a greater distance the 
 sun attract the less, centrifugal force must repel the less, to 
 preserve the curve. 
 
 The velocity of a planet is determined by its distance 
 from the sun. Unbalanced attraction and repulsion cannot 
 give a determinate distance, balanced attraction and re- 
 pulsion neutralize each other at any distance. We believe, 
 then, that we must go at once for the curve of the orbit, not 
 to an original impulse of motion, but to the intensity of the 
 force present to the planet. It is this, and this only, that 
 determines the distance, the curve of the orbit. It is the 
 intensity of the impelling force which governs the revolu- 
 tion of the spheres. Mathematicians, for the purposes of 
 calculation, may refer to attractive and repulsive forces, 
 may resort to any fictions or hypotheses which aid their 
 processes ; but in philosophy these imaginary lines can at 
 once be discharged. We may look to the heavens with 
 more simple and comprehensible ideas. We may clear the 
 starry hosts from all mathematical intricacies, and no longer 
 associate the planets with radial and tangential forces, and 
 the complex fictions of human weakness ; we may regard the 
 majesty of their movements as true to the one great law, 
 velocity in proportion to orbit, distance according to the 
 impelling force, the spheres as united and oscillating as a 
 great whole by the sweep of the bands of power, yet each 
 pursuing its own course by its own inherent energy, cen- 
 
296 OUTLINES OF A SYSTEM OF 
 
 turies upon centuries passing over them, yet in all their 
 complex relations no permanent change. 
 
 We do not mean by these remarks to undervalue mathe- 
 matical research. Mathematics has its power from its pecu- 
 liar exactness of reasoning, and the definite language which 
 it employs in its processes. Mathematical training gives the 
 power of concentrated thought ; but, as with all other kinds 
 of reasoning, its results, whether beneficial to the world or 
 not, depend on the character of the mind which employs it. 
 It is not an end, but an instrument ; its value consists not in 
 the ability with w T hich the instrument is used, but in the 
 work accomplished by it. Connected with the physical 
 sciences, it may uphold error as well as advance truth.* 
 
 But there is an error which has done much evil in the 
 world ; that is, that it requires the power of abstract mathe- 
 matical reasoning to understand mechanical philosophy. It 
 is not so. The truth, if there are truths only to be arrived 
 at by the process of mathematical reasoning, will be fur- 
 nished by the mathematician. His results, if valuable, can 
 be translated into the popular language. Mathematical 
 investigation is a process, not a result, an aid, but not 
 success. Ferguson, who was surely distinguished by his 
 
 * Stewart, in his Philosophy, deprecates " that unqualified application of 
 the mathematical method to physics, which has heen fashionable for many 
 years, and which seems to have originated chiefly in the commanding influ- 
 ence which the genius of Leibnitz has so long maintained over the scientific 
 taste of most European nations." He speaks "of the obvious tendency 
 which it has to withdraw the attention from that unity of design which it 
 is the noblest employment of philosophy to illustrate." . . . ' ; The conse- 
 quence has been, (in too many physical systems,) to level the study of 
 nature in point of moral interest with the investigations of the algebraist, 
 an effect which has taken place most remarkably, when, from the sublimity 
 of the subject, it was least to be expected, in the application of the mecha- 
 nical philosophy to the phenomena of the heavens." 
 
MECHANICAL PHILOSOPHY. 297 
 
 astronomical knowledge, hardly knew the notation of alge- 
 bra, and could not demonstrate a proposition of Euclid ; and 
 Kepler, whose name is indelibly impressed on the planetary 
 system, was not even a good arithmetical calculator. Phi- 
 losophy is not thus fenced out from men of ordinary educa- 
 tion and common sense. The truths to be understood are 
 few and simple ; and it would be of great service if the 
 general principles of philosophy were examined by those 
 who have no educational bias to any of the present theories ; 
 the whole, after all, is but an appeal to the common sense 
 of those who are sufficiently educated to understand the 
 subject. 
 
 It is admitted that gravitation cannot account for the 
 form and orbits of comets ; and, if not for these, then it 
 cannot for the minor eccentricities of the planets. The 
 difference is in degree only, not in character. Sir John 
 Herschell, in speaking of a comet, says that the laws of gra- 
 vitation are insufficient to account for such a form of equi- 
 librium, and that such a form is inconceivable without the 
 admission of repulsive, as well as of attractive forces. " But 
 if we admit the matter of the tail to be repelled from the 
 sun, and attracted by the nucleus, it no longer presents any 
 difficulty." He hazards the opinion, in order to obtain a 
 repulsive power, that " the sun is permanently charged 
 with electricity." Arago found that the attractive force, as 
 exercised on heavy bodies, is inadequate to explain some 
 peculiar motions of comets ; and is of opinion that these 
 motions " indicate a polar force which turns one semi- 
 diameter towards the sun, and strives to turn the opposite 
 side away from that luminary." To aid the theory of gravi- 
 tation in its application to comets, the supposition of a retard- 
 ing medium has also been advanced, but with little success. 
 
298 OUTLINES OF A SYSTEM OF 
 
 The difficulty, as we have said, is not in the character of the 
 motions of these bodies ; but the great degree of the eccen- 
 tricity of their orbits, shows plainly a defect in the theory 
 of gravitation, which escapes notice when eccentricity bears 
 but a small proportion to the diameter of the body or to its 
 orbit of revolution. It is impossible not to perceive that 
 the sun has not an attractive power, when we trace the mo- 
 tion of a comet. We will suppose a comet, millions of millions 
 of miles away from the sun, moving from him under the 
 impulse of its impelling force, until the central attraction, 
 when immeasurably weakened by distance, changes the 
 direction of the wanderer and recalls it toward the centre ; 
 it returns rushing toward the sun, almost in a straight line, 
 and when so near that another quarter of an hour would 
 bring it into contact with the central luminary, at this near 
 point, although attracted to the centre with a force almost 
 as great as that with which the sun binds together the parts 
 of his own mass, it again speeds away against the full force 
 of the sun's attraction. 
 
 Nor can the sun give form to the orbits of the planets ; 
 for he cannot, with a force invariable on the same mass and 
 at the same distance, determine the form of the ellipses, or 
 the degree of the eccentricity. Attraction does not shape 
 the orbit. We are somewhat acquainted with the mathe- 
 matical reasoning by which the unvarying central force is 
 supposed to give the modifications. But, after all, an equal 
 central force acting on any heavenly body at any one dis- 
 tance, cannot do aught but maintain that distance against 
 the uniform centrifugal force, which is measured by the 
 intensity of the impulse of motion. If there are changes of 
 velocity and changes of curve, they must come from a 
 change in the force which determines the motion. There 
 
MECHANICAL PHILOSOPHY. 299 
 
 is something belonging to the planet, not to the sun, a 
 change at the circumference, not at the centre of revolu- 
 tion, which gives the peculiarities of the orbit. The differ- 
 ence between the orbits of Mercury and Venus, for instance, 
 comes not from solar influence ; this influence varies only 
 with the mass and the distance. It is not mass or distance 
 that determines eccentricity. Therefore, that which gives 
 a different character to the orbits of these two planets is 
 local, and peculiar to each. The eccentricity of the orbit 
 does not come from central attraction, nor does its elliptical 
 form ; nor consequently, does the mean distance, nor the 
 curve, nor indeed any peculiarity of the orbit of any planet. 
 
 To our mind it is another disproof of the theory of gravi- 
 tation as applied to the heavenly bodies, that it throws 
 over the solar system a complicated irregularity. It takes 
 away symmetry, the simple and orderly relation of the 
 spheres ; by the arrangement of masses to suit the theory it 
 destroys the idea of regular progression. For instance, the 
 theory presents the moon as a mass of vapor compared with 
 its primary, while one of Jupiter's satellites is made more 
 dense than Jupiter himself. One planet is puffed up, 
 another unnaturally hardened, and relative density skips 
 back and forth without method or order. Uranus is less 
 dense than Saturn ; Venus and Mars less dense than the 
 Earth, which lies between them. As it has been most sin- 
 gularly expressed, some are as light as vapor, and some 
 heavy as lead ; and between the extremes are those of the 
 consistency " of water, of honey, of antimony, and of pine 
 wood," all confusedly intermingled for the purpose of 
 adapting the heavens to the theory of gravitation. 
 
 To show that we do not exaggerate in these statements, 
 we will quote from a standard authority. " The planetary 
 
300 OUTLINES OF A SYSTEM OF 
 
 system in its relations of diameter and relative position, in 
 density, time of revolution, and eccentricity of orbit, does 
 not offer to our apprehension, any stronger evidence of 
 natural necessity than the proportion observed in the distri- 
 bution of land and water on the earth, and the height of 
 mountain chains. In these respects we can discover no 
 common law in the regions of space, or in the irregularities 
 of the earth's crust." And the heavenly bodies are pre- 
 sented " as facts arising from the conflict of forces acting 
 under unknown conditions." We cannot avoid the belief, 
 that no theory can be sound which does not unfold the 
 beautiful symmetry and perfection of the universe. 
 
 It has been found that the diameter of the earth multi- 
 plied by one hundred and ten, gives the sun's diameter, and 
 that this product, the sun's diameter, multiplied by one hun- 
 dred and ten, gives the distance of the sun from the earth ; 
 and also that the moon's diameter multiplied by one hundred 
 and ten, gives her distance from the earth : 
 
 7920 X 110 = 871,200, observed diameter 880,000 
 871,200 x HO = 95,832,000, " distance 95,000,000 
 
 2160x110 = 237,600, 237,400 
 
 It appears from this, that the diameters of the heavenly 
 bodies have not only a fixed proportion to each other, but 
 also to their distances one from the other. Diameters there- 
 fore are not, if we may be allowed the expression, deceptive ; 
 they have an honest value. It is the circumference of the 
 planet and the sweep of its orbit, that determines its relation 
 to others. Magnitudes as presented to the astronomer are 
 more reliable than speculations as to density. The one, 
 accurate instruments and close observation will give with 
 great exactness ; the other, however acute may be the 
 mathematician, however sound his system of calculation, 
 may be altogether erroneous. 
 
MECHANICAL PHILOSOPHY. 301 
 
 We do not believe that it was by the " conflict of mani- 
 fold forces," that a one-hundred-and-tenth part of the sun 
 was torn off, and carried one hundred and ten times his 
 diameter in distance, there to be consolidated and shaped 
 under the direction of the centripetal and centrifugal forces ; 
 and that the accompanying vapors were rolled off so as to- 
 form a moon exactly one hundred and ten times its diameter 
 in distance from the earth. We believe that the diameters 
 of the heavenly bodies are measured one by the other, and 
 bear to one other a fixed proportion ; that the same meas- 
 ure was used, and was guided by the same hand all over 
 the system of worlds ; that all apparent disorder or irregu- 
 larity is the distortion of facts as seen through the mists of 
 our ignorance. 
 
 We will assume for Mercury a diameter of three thousand 
 six hundred miles, and compare this with the diameters of 
 Venus, Earth, the Moon, and Mars. If we discover a fixed 
 relation in their magnitudes, we may reasonably suppose 
 that the chain of progression extends through the wnole 
 system, even if some of its connecting links are hidden. 
 
 Mercury, 3,600 observed diam. 3,240 
 
 Venus, . . . 3,600 + 3,600 = 7,200 " " 7,700 
 
 Earth and Moon, 7,200 + 7,200 = 14,400 assumed value, 14,400 
 
 Earth, .... 7,200 + 720 = 7,920 observed diam. 7,920 
 
 Moon, .... 720 + 720 + 720 = 2,160 " " 2,160 
 
 Mars, .... 2,160 + 2,160 = 4,320 " " 4,180 
 
 39,600 miles 39,600 
 
 The aggregate of our assumed diameters, as thus " double 
 one against the other," is the aggregate of the observed 
 diameters ; and, while the aggregates thus agree, the diam- 
 eters assumed for each do not vary materially from the 
 magnitudes given by the astronomer. If we can show that 
 the value of the moon by increased rotation is 6480, or in 
 
 26 
 
302 OUTLINES OF A SYSTEM OF 
 
 other words, that the joint value of the earth and moon is 
 14,400 miles, we establish the fact that the diameters of 
 the planets are " built one upon the other." * 
 
 The velocity of the earth's rotation at the equator 
 may be stated as 1,037 miles an hour. If the diameter 
 of the earth were increased by the diameter of the moon, 
 (7,920 + 2,160 = 10,080,) rotation in the same time would 
 give a velocity of about 1,260 miles an hour. The velocity 
 of the moon's rotation is 2,300 miles an hour. This is 
 made up of the increase of 230 miles, which would ensue 
 were she a component part of the earth, and of twice the 
 earth's velocity, constituting the 2,070 miles. Thus, her ro- 
 tation at the circumference of the local system is three times 
 the value of the rotation of the earth at the equatorial regions. 
 
 Earth, v> ^: . .- 7,920 
 
 Moon, 2160x3 = 6,480 
 
 14,400 miles. 
 
 By the multiplication of 14,400 by 16, we have 230,400 
 miles, the minor axis of the moon's orbit ; by the multipli- 
 cation of 14,400 by 17, we have 244,800, the major axis. 
 The eccentricity of the ellipse of the orbit is stated at T J T . 
 The mean of the two extremes 237,600 is exactly the mean 
 distance of the moon from the earth as deduced by obser- 
 vation, and is the distance as obtained by the multiplication 
 of the moon's diameter by 110. 
 
 The distance of Jupiter is 5 times the distance of the 
 earth from the sun. 14,400 X 5 = 79,200, which is the 
 small diameter of Jupiter. If we multiply the moon's 
 diameter by 5^, we have 11,880, which is about the aggre- 
 
 * These " numerical coincidences " extend through the whole system. 
 
MECHANICAL PHILOSOPHY. 303 
 
 gate of the observed diameters of Jupiter's satellites, 
 namely, 2508 + 2668 + 3377 + 2890 = 11,443 miles. 
 
 The mean distance of Mercury from the Sun is thirty- 
 eight millions of miles, or forty-five times the Sun's diameter. 
 Deduct one diameter, and 44 X 2 = 88 gives the revolution 
 of Mercury in days. The moon is 16^- times 14,400 miles 
 from the earth ; 15J- X 2 = 31 days rotation. Is this a 
 mere numerical coincidence ? * 
 
 The sidereal revolution of the moon is, say twenty-seven 
 days ; the sun's rotation, as increased in relation to the 
 earth by the earth's motion in the same direction, is twenty- 
 seven days. In movements thus involved and combined, the 
 sun and moon rotate the same number of times for every 
 revolution of the earth. Are the form of the orbit, the cir- 
 cumference of the planet, and its motion, determined by its 
 mass and distance according to the theory of 'gravitation ? 
 We rest in the belief of a perfect symmetry of all the parts 
 of the solar system, and a close sympathy of motion consti- 
 tuting the universe a perfect whole. 
 
 The preceding are rough calculations, selected from many 
 of the same character, not as the most striking, but because 
 in a simple, unartificial manner, they present the fact ^that 
 the diameters of the spheres, as it were, grow out of each 
 other, and that there is a determinate relation of magnitude 
 and distance running through the system of worlds. The 
 
 ^Mercury, 45 X 2 = 90 days, observ. 88 days 
 
 Venus, . . . . 45 + 22 = 674 X 3 = 202 " " 220 " 
 Earth, . . . . 674 + 224= 90 X 4 = 360 " " 365 " 
 Mars, . . . . 90 +45 =135 X 5= 675 " " 685 " 
 Vesta, . . . .135+90 =225 X 6 = 1350 " " 1350 " 
 We thus roughly indicate a regular progression of the times of resolu- 
 tion, which can be extended through the system with striking numerical 
 coincidences. 
 
304 OUTLINES OP A SYSTEM OF 
 
 relations of these bodies to one other seem to demand the 
 greater attention ; for, when distinctly traced out, all seem- 
 ing incongruities will vanish, and order will be restored to 
 the heavens, or, in other words, the mind in sympathy with 
 nature will discover the order that ever has reigned and 
 ever will reign supreme. 
 
 From the sudden decrease of the diameter of Mars rela- 
 tively to that of the Earth, analogy would lead us to believe 
 in a satellite or satellites accompanying Mars. But the tel- 
 escope does not reveal the existence of these attendants. 
 What are the relations of the Asteroids to Mars ? 
 
 By a hasty generalization we are disposed to end the first 
 series of planets with the Earth, and to consider Mars as 
 intermediate, or pertaining in some degree at least to the 
 system of worlds between the Earth and Jupiter. Is there 
 not another system of Asteroids between Saturn and Ura- 
 nus, and another beyond the bounds of Neptune, and does 
 not system thus interlace with system through the great 
 whole ? 
 
 We turn our attention for a moment to the nebular 
 hypothesis, a short time since so generally believed, now 
 fading away under the clearer light of modern science. It 
 has been thus described : " The assemblage of stars that 
 form at present our solar system, were first confounded in 
 one celestial body, resembling one of those mysterious 
 nebulas we see floating in the celestial spaces." . . . . " But 
 soon the development begins. A principle of concentra- 
 tion, gravitation, counterbalances the unlimited expan- 
 sion of the gaseous matter, brings the molecules nearer 
 together, and groups them in a spheroidal mass. This ap- 
 proximation allows the molecules different in nature to act 
 upon each other according to their chemical affinities ; the 
 
MECHANICAL PHILOSOPHY. 305 
 
 process of life commences, and its earliest manifestation is 
 light and heat. The nebula is detached from the general 
 mass, under the form of a luminous spheroid traced in the 
 obscurity of the heavens. This is the first step in the pro- 
 cess of formation." " This gaseous spheroid then resolves 
 itself into local agglomerations, which, while concentrating 
 each in itself, under the influence of gravitation and chemi- 
 cal combinations, separate from each other in distinct 
 spheres. Whether this phenomenon is effected, as La Place 
 imagines, by the successive separation and agglomeration of 
 concentric layers of the solar atmosphere, or in virtue of 
 some organic law still unknown, is of little importance here. 
 The fact of the separation of the different bodies of our solar 
 system into a number of spheres, planets, and satellites, is 
 not less certain, and constitutes one of the essential and 
 incontestible phases of its development." 
 
 From another work we extract: "The idea, then, 
 which I form of the progress of organic life upon the globe, 
 (and the hypothesis is applicable to all similar theatres of 
 vital being,) is, that the simplest and most primitive type 
 (under the law to which that of like production is subor- 
 dinate) gave birth to the type next above it, and this again 
 produced the next higher, and so on to the very highest." . . . 
 " It has been seen that, in the reproduction of the higher 
 animals, the new passes through stages in which it is suc- 
 cessively fish-like and reptile-like." We make these quota- 
 tions to give what is called the progressive theory as applied, 
 not only to world-making, but also to the development of 
 animal life. 
 
 To all these theories we may apply the language of 
 Cudworth ; we quote from his Intellectual System of the 
 Universe, first published in 1678. " Wherefore, infinite 
 
 26* 
 
306 OUTLINES OF A SYSTEM OF 
 
 atoms of different sizes and figures, devoid of all life and 
 sense, moving fortuitously from eternity in infinite space ; 
 and making successively several encounters, and conse- 
 quently various implexions and entanglements with one 
 another, produced first a confused chaos of these omnifarious 
 particles, jumbling together with infinite variety of motions ; 
 which afterward, by the tugging of these different and con- 
 trary forces, whereby they all hindered and abated each 
 other, came, as it were, by joint conspiracy, to be conglom- 
 erated into a vortex or vortices ; where, after many convo- 
 lutions and evolutions, molitions and essays (in which all 
 manner of tricks were tried, and all forms imaginable exper- 
 imented,) they chanced, in length of time, here to settle 
 into this form and system of things, which now is, of earth, 
 water, air, and fire ; sun, moon, and stars ; plants, ani- 
 mals, and men ; so that senseless atoms, fortuitously moved, 
 and material chaos, were the first original of all things." 
 
 There is another theory somewhat more recently revived. 
 It is the opposite of the development hypothesis, whether 
 applied to world-making, or to the production of the higher 
 orders and types of animal life from the lower. It is the 
 very reverse, a degradation theory ; and shows us ani- 
 mal life sinking below its former level. The reptiles, for- 
 sooth, are not so large as they once were. There are 
 species of fishes brought into existence with eyes misplaced, 
 and mouths askew. We will again quote from Cud worth : 
 " Wherefore, they affirm that the earth brought forth divers 
 monsters, and irregular shapes of animals ; 
 
 " Orba, pedum partim, manuum viduata vicissim, 
 Multa sine ore etiara, sine vultu, ca3ca reperta." 
 
 Of course, we do not impute these speculations to the the- 
 
MECHANICAL PHILOSOPHY. 307 
 
 ory of gravitation. They are not new. In the old atomic 
 philosophy, long before the theory of gravitation was an- 
 nounced, they were presented. But it is an objection to 
 this theory, that it permits the belief of the world-making 
 and life-giving power of matter, as resuscitated in modern 
 times, to find a resting place in the mind. If it does not 
 produce the nebular, the progressive, and the degradation 
 hypotheses, it does not place itself as a barrier against 
 their introduction. This theory and these speculations are 
 not in opposition to each other ; and it behooves those who 
 would maintain the doctrine of the attractive power of 
 matter, so to limit this power that it sha41 never be repre- 
 sented as the potential cause of all things. 
 
CHAPTER XII. 
 
 "IF HIS SUN ROLLS OVER MY HEAD AND WARMS ME, IF HIS WIND 
 COOLS AND REFRESHES ME, IF HIS VOICE SPEAKS TO ME, WHETHER 
 IN THE THUNDER AT MIDNIGHT, OR IN THE WHISPERS OF THE 
 FOREST, OR BUT IN THE RUSTLING OF A LEAF, IF HIS SEASONS 
 STILL COME ROUND TO ME IN THEIR GRATEFUL VICISSITUDE, 
 AND WHEREVER I LOOK IN OUTWARD NATURE, I BEHOLD CONSTANT 
 ACTION, CHANGE, AND JOY, I DO NOT SUPPOSE THAT BRUTE AND 
 SENSELESS MATTER CAUSES ALL THIS BY ITS INHERENT POWER, 
 WHETHER ORIGINAL OR DERIVED, BUT THAT THE SPIRIT, THE 
 PERSON WITHIN, CONTROLS, VIVIFIES, AND PRODUCES ALL." 
 
 Francis Bowen. 
 
 IT may be said that if our assertion, that the earth is sub- 
 ject to occasional and periodic oscillations of surface, were 
 correct, these oscillations would be indicated by cracks and 
 fissures ; that as earthquakes show their agitations, so would 
 these fluctuations declare themselves by inequalities of sur- 
 face. But this would not follow ; for earthquakes are lim- 
 ited, abrupt disturbances, while the more gentle undulations 
 of the earth, which we suppose, would be analogous in their 
 movements to the bending of an elastic spring, the curve of 
 which is too gradual and too extended to produce any rup- 
 ture in its parts. Elevation of the earth's surface would 
 gradually fade away into depression without any break or 
 abrupt change to mark its bounds. 
 
 The Britannia tubular iron bridge, it is said, at times 
 contracts and expands to the extent of three inches. This 
 
MECHANICAL PHILOSOPHY. 309 
 
 is a much greater change of atomic structure in proportion 
 to the length of the bridge, than the change in the structure 
 of the earth necessary to produce the rise and fall indicated 
 by the barometer. " The action of the sun at mid-day does 
 not move the tubes of the bridge more than a quarter or 
 three eighths of an inch. The daily expansion and con- 
 traction of the tubes varies from half an inch to three inches, 
 attaining either the maximum or minimum about 3 o'clock, 
 A. M. and P. M." This statement is copied from a London 
 paper ; if correct, it is in some degree a confirmation of our 
 views. 
 
 Unquestionably there are many plausible objections that 
 can be urged against the hypothesis which we have offered. 
 It is of course incomplete ; there is much to be learned ; 
 much remains for examination, much for further explanation. 
 We but indicate the mine, presenting only specimens of the 
 surface-ore, not the raised and refined metal. The laws of 
 force require assiduous attention for their development, as 
 the currents of its transfer must necessarily be numerous 
 and complicated. 
 
 Our system has not the simplicity of the theory that all 
 matter attracts according to one unvarying law, nor is it so 
 readily and easily applied. And for this very reason we 
 believe that our explanation is more true to nature ; for, 
 while it throws a clear light over some prominent phenome- 
 na, it has not the vagueness which would permit its applica- 
 tion at once to every fact. On the other hand, a theory may 
 cover a vast ground from its very vagueness and indefinite- 
 ness. A loose and unshaped robe can be thrown over any 
 form ; but this easy adaptation does not prove that it is a 
 fitting, useful garment. A theory is not proved to be true 
 by the readiness of its application. The truth on the other 
 
310 OUTLINES OF A SYSTEM OF 
 
 hand, because of its exactness, shows its adaptation only 
 where the fact to which it is applied is well understood, and 
 its application can be extended just in proportion as the 
 relations of things one to another are distinctly traced out. 
 A true theory will be a theory of progress. Its reception 
 will be marked by a constant advance in knowledge. 
 
 Suppose it were asserted that all matter was originally 
 created in one dense and compact mass, and that then a 
 repulsive power was given to it, increasing in intensity in 
 direct proportion to distance and in inverse proportion to 
 mass ; or that space has no fixed and definite extension, but 
 that it contracts and expands with an intensity in propor- 
 tion to the mass and distance of the bodies which it sepa- 
 rates. All facts could be at once arranged under these 
 absurd hypotheses. They merely assert that things are 
 placed as they are placed. Does the more reasonable the- 
 ory of gravitation give any brighter light ? Is it not char- 
 acterized by the same vagueness, and the same readiness of 
 application to all the phenomena of the universe ? 
 
 In former times chemistry divided all matter into four 
 elements, earth, air, fire, and water. This is a simple clas- 
 sification, intelligible and applicable at once. Had it been 
 retained, however, the science could have made no possible 
 advance. It therefore soon abandoned this easy generaliza- 
 tion. In its progress it has divided and subdivided, and it 
 now presents us some sixty elements, and these combined 
 and separated by the conflict of manifold forces. But it 
 will not remain a confused collection of facts. It will be 
 reconstructed on a sure foundation. It will by its minute 
 exactness advance to general principles, and while it de- 
 velops the relations of atoms, and of the constituent ele- 
 ments of masses, it will discern the unity of force, and 
 
MECHANICAL PHILOSOPHY. 311 
 
 discover the general dynamic laws which have remained 
 hidden because philosophy has supposed that already, in the 
 law of attraction, it has attained its ultimate knowledge of 
 the properties of matter. 
 
 There is some reason, therefore, to question a theory 
 of too ready application, which does as much for the ad- 
 vance of science at first, at its very inception, as after the 
 lapse of years. A theory may be apparently useful in col- 
 lecting all minor doubts into one general doubt, in remov- 
 ing obstacles from the by-paths of science, while it gathers 
 together all those obstacles and forms a barrier in the high- 
 way of progress. The leading fact, on which the law of gra- 
 vitation is founded, is the fall of bodies to the earth. To 
 this fact it owes its origin. Of course, if it can explain 
 aught with exactness, if it can give clear ideas in relation 
 to any phenomena, if it have strength, perspicuity, dis- 
 tinctness of illustration, unquestionable adaptation, here it 
 will be found. And if in its application to a falling stone 
 the mind receives no clear light, if even this fact remains 
 enveloped in a mist of obscurity, surely there is some reason 
 to question the value of the theory in its more remote and 
 extended applications. We will now examine the theory of 
 attraction as explanatory of the fall of bodies to the earth. 
 
 It is said that falling bodies move faster and faster the 
 longer they continue in motion. To explain this accelerated 
 velocity, we are told that " the force of gravitation acts not 
 at once, but at every period of descent ; of course the velo- 
 city increases as the time increases ; hence the space de- 
 scribed must be as the time multiplied by the velocity, 
 which is the same thing as to say that the space described 
 is as the square of the time, or the time multiplied by itself." 
 
 Now is it invariably true that falling bodies move faster 
 
312 OUTLINES OF A SYSTEM OF 
 
 and faster the longer they continue in motion ? Does the 
 force of gravitation act, not at once, but at every period of 
 the descent ? The answer must be that this is not rigorously 
 true in relation to bodies falling in an arc, as in the case of 
 a pendulum, nor in the case of water in downward motion 
 over an inclined plane. The space described by a falling 
 body is as the square of the time, only when the fall is 
 perpendicular. 
 
 It is the change of the level of rotation which gives the 
 uniformly accelerated motion. The velocity has no relation 
 to the time of the fall, nor to the space described by the 
 motion. It is measured by the degree of the change in the 
 orbit of rotation. This is the only statement rigorously 
 true, and universally applicable to all the circumstances of 
 a falling body. If we divide the space of the perpendicular 
 fall into equal parts, the velocity of the first part will be as 
 one, of the second as three, of the third as five, and so on ; 
 for the force of any part of the descent will be its own spare 
 force of descent, with the addition of the force of the pre- 
 ceding parts. The same degree of force always describes 
 the same space in the same time ; therefore in the perpen- 
 dicular fall the product is the same, whether the time or 
 the space is squared. 
 
 The question then is, whether the uniformly accelerated 
 motion of a falling body is the result of the time in which it 
 has been moved by the gravitating power, or whether it is 
 the result of the change of the level of rotation. 
 
 On our theory, the spare force of rotation being deter- 
 mined by the degree of the change of level, the downward 
 motion of the falling body would have an increasing velocity ; 
 for the spare force increases with every line of actual descent. 
 However minute the division of the space, the force at every 
 
MECHANICAL PHILOSOPHY. 313 
 
 division and the velocity at every division would be doubled. 
 Hence the reason for squaring, or multiplying by itself, the 
 space described by the fall. It is just what would be 
 affirmed as the result of the theory, without recourse to 
 observation, experiment, or admeasurement. 
 
 On the other hand, a uniform acceleration of the motion 
 of a falling body could never have been supposed as a neces- 
 sary result of the attraction of the earth, and when observa- 
 tion presents the fact, the law of gravitation can give no 
 explanation or elucidation of it. According to the theory, 
 the power of attraction varies only with the mass and with 
 the distance. The accelerated motion is from an increased 
 force without an increase of the attracting mass, and a force 
 increased far beyond what the lessening distance could 
 supply. 
 
 Most unquestionably, an increasing velocity of motion 
 under the same circumstances implies a greater producing 
 force. To obviate this difficulty, it is supposed that the 
 attraction of the earth is cumulative, increments of force 
 being added in proportion to the time in which the earth 
 attracts. Why then does not the earth's attraction accu- 
 mulate in the body when at rest, giving it more and more 
 weight or tendency to descend ? Why does not this attrac- 
 tion accumulate in water falling over an inclined plane ? 
 The water is in motion uniformly and constantly towards the 
 earth. How does the earth, when putting forth an increas- 
 ing attractive power, discriminate between bodies at rest, 
 bodies moving obliquely downwards, and those in direct 
 motion toward her centre ? How does the earth propor- 
 tion the velocity to be added to that already conferred ? 
 The theory of gravitation seems to require an intelligent 
 attracting power, with a nice perception of time, and the 
 27 
 
314 OUTLINES OF A SYSTEM OF 
 
 ability of making mathematical calculations, so that force 
 shall be added in the right degrees, according to the chang- 
 ing circumstances of the moving body. 
 
 Galileo, who first announced the law of the square of the 
 time, was much perplexed by it, and ascribes it, somewhat 
 doubtingly, to the simplicity of the works of nature, saying, 
 "If we attend carefully, we shall find that no mode of 
 increase of velocity is so simple as that which adds equal 
 increments in equal times ; as the uniformity of motion is 
 defined by the equality of spaces described in equal times, 
 so we may conceive of the uniformity of motion to exist 
 where equal velocities are added in equal times." Had 
 this train of reasoning been followed out, the acceleration 
 would have been imputed to the change of level, to the dis- 
 tance of the fall, not to the length of the time of the fall ; 
 it would have been traced to the body falling, not to the 
 earth on which it falls, to a varying force, not to the uni- 
 form force of attraction. But this reasoning could not be 
 resorted to by those who believe gravitation to be the cause 
 of motion ; therefore to this day remains the singular 
 explanation of the uniform acceleration of falling bodies, 
 that, to bodies in motion the earth adds constantly increas- 
 ing increments of force to be measured by the squares of the 
 times ; that is, the power of attracting increases with the 
 use of the power. 
 
 From this it follows that there are two differing attrac- 
 tions, the attraction which gives weight and that which 
 causes motion, the one of stationary intensity, the other 
 increasing with the time of its action. A stone on the sum- 
 mit of a mountain has been attracted for ages without an 
 increase of weight ; when it falls how rapid is the increase 
 of the power which draws it downward ! 
 
MECHANICAL PHILOSOPHY. 315 
 
 How simple and intelligible is the idea that the earth has 
 no influence whatever in the fall of a stone, that she im- 
 parts neither a uniform impulse nor constantly increasing 
 impulses, that the force is always, invariably, in the body 
 which moves, that it is the extent of the fall, not the time 
 of the fall, which measures the extent of the force liberated 
 from the force of rotation, that this force according to its 
 intensity gives motion, not downward only, but laterally and 
 upward, that, if the space described between the two 
 levels of rotation of the descending body is measured, the 
 quantity of force liberated to act in a new direction is ascer- 
 tained. This simple solution takes away all the mystery 
 which so long has enveloped the subject. 
 
 And the converse act, the raising of a stone to a superior 
 level of rotation, confirms this view. To a stone at rest, 
 additional force for its new relative position must be applied, 
 and, however supplied, its intensity is just the force of its fall 
 through the same distance ; in fact, the force of the fall is the 
 force for the rise, as is shown in the oscillations of a pendulum. 
 
 But what is gravitation ? "A name," said one of our 
 strongest men, " that is given to the veil which covers the 
 unknown from our sight." Its original signification was 
 heaviness. Transferred from the tendency to descend to 
 the act of descent, from the act of descent to the "effect of 
 descent, from the effect of descent to the principle by which 
 all bodies descend, thence it went from the earth to the 
 heavens, first deflecting or bending the otherwise straight 
 line of the motion of the moon, then curving the orbits of 
 all the planets, then serving as the impelling power of the 
 sphere, then as the cause of all the perturbations of the 
 orbits of the planets, and of the eccentricity of the orbits of 
 the comets, then causing the motion of the binary stars, one 
 
316 OUTLINES OF A SYSTEM OF 
 
 around the other, and wheeling the astral systems around a 
 centre in the direction of the Pleiades. Returning again 
 to the earth, attraction takes under its ample folds every act 
 of masses, every motion of atoms, the first, last, and only 
 cord by which philosophy ties the creation together, in 
 atoms, masses, worlds, and systems of worlds, aided perhaps 
 somewhat by centrifugal force, the abhorrence of nature 
 for curvilinear motion ! 
 
 The gradual extension of the power of gravitation is well 
 known by those who pierce 
 
 -.* "the long-neglected, holy cave, 
 
 The haunt obscure of old Philosophy." 
 
 Long before the days of Newton, the doctrine of the attrac- 
 tion of the earth was taught and generally believed. Mag- 
 netic attraction was the matrix of the idea. An analogy 
 was early traced out between the descent of falling bodies 
 and the rushing of particles of iron to the magnet. Thus 
 was established a supposed principle, a tendency or desire 
 of bodies for the presence of each other, an idea which is 
 thus curiously expressed by Bacon : " The electrical 
 operation, concerning which Gilbert and others since him 
 have made up such a wonderful story, is nothing else than 
 the appetite of a body excited by friction." This appetite 
 of matter for matter was the germ of the theory, which has 
 taken such rapid strides from its inception by the elder 
 philosophers to the present conception of the schools. 
 
 The great extension of this appetite of the earth for the 
 matter of adjacent masses to an appetite for the matter of 
 the moon, dates from the time of Sir Isaac Newton. Be- 
 fore his time it was hinted at, supposed, timidly expressed, 
 considered possible. The idea had never been distinctly 
 
MECHANICAL PHILOSOPHY. 317 
 
 avowed. It was in men's minds a " shadowy belief.'' Its 
 destined enunciation was reserved for after-times. New- 
 ton, as we shall see, disclaimed the belief. 
 
 The first conception that the attraction of the earth 
 extended to the other spheres thus took its rise. When a 
 body is falling to the earth, it also partakes of the motion of 
 the earth around its axis. Hence the idea that, some how 
 or other, the fall to the earth is connected with the motion 
 of the earth. The fall of an apple from the mast-head of a 
 ship, which partakes also of the motion of the ship, and be- 
 tween the two forces describes a curve in its fall, is one of 
 the connecting links of the fabrication of the chain of attrac- 
 tion, both motions in the same time, one modifying the 
 direction of the other, surely they indicate one cause ! 
 
 The idea had, however, its refining process, its transition 
 state, before being fully incorporated into philosophy. " A 
 ball thrown from a cannon describes a curve by the mutual 
 action of the impelling force and the force of attraction. 
 The explosion of the gunpowder would of itself give the 
 rectilinear line, the curve is therefore the action of gravita- 
 tion." The next step was, " If the impelling force of the 
 explosion were sufficient, it would so far overcome the force 
 of gravitation, that the ball would describe an orbit round 
 the earth, without descending to its surface ; if the impel- 
 ling power were sufficiently great, gravitation would act 
 only in giving the cannon ball an orbit of rotation round the 
 earth like the orbit of the moon." Then came the mathe- 
 matical demonstration, that an arc of the deflection of the 
 moon's orbit, cut off for the calculation, is equal to the fall 
 of a stone for an equivalent period of time. This settled all 
 doubts, and the principle of gravitation, going up to the 
 moon, from this elevation could easily soar higher to cover 
 
318 OUTLINES OF A SYSTEM OP 
 
 all the motions of the heavenly bodies. There is no hin- 
 drance now to any further extension, because, attraction 
 being according to the density, as well as according to the 
 distance of any sphere, philosophy can give to any of the 
 heavenly bodies just the required power. Assume the law, 
 then most easily can density be adjusted, so as to bring the 
 power of the attraction of any star to the limits necessary 
 for the theory. For instance, the sun has too great attrac- 
 tive power according to bulk for the theory, but what of 
 this ? Tlis density can be arranged so as most exactly to 
 suit the theory. For this reason no sphere can trouble the 
 theory, and difficulties are met with only in comets ; for in 
 their case there is too much indistinctness, neither the bulk 
 nor the mass of these bodies being known. 
 
 It is generally believed that Newton mathematically de- 
 monstrated that the attraction which impels a falling stone, 
 gives the deflection of the orbit of the moon, that is, ad- 
 mitting that the impulse which gave motion to the moon, 
 was at the beginning an impulse of rectilinear motion, that 
 the attraction of the earth gives the curvilinear form, and 
 determines the circle of her revolution. We copy an abstract 
 of the demonstration from the London Encyclopedia, Article, 
 Newtonian Philosophy, as in a very few words it conveys 
 the process. " If we imagine the moon deprived of all her 
 motion, and be let go so as to descend toward the earth 
 with the impulse of all that force by which it is retained in 
 her orbit, it will in the space of one minute of time describe 
 in its fall 15 Paris feet ; for the versed sine of that arc, 
 which the moon describes in the space of one minute by its 
 mean motion, at the distance of sixty semi-diameters of the 
 earth, is nearly 16 T V Paris feet. Wherefore, since that 
 force in approaching the earth increases in the reciprocal 
 
MECHANICAL PHILOSOPHY. 319 
 
 duplicate proportion of the distance, and upon that account 
 at the surface of the earth is 60 X 60 greater than at the 
 moon, a body in our regions falling with that force ought in 
 the space of one minute of time to describe 60 x 60 X 15 
 Paris feet, and in the space of one second of time to describe 
 15J of those feet, and with this very force we actually find 
 that bodies here on earth do actually descend." 
 
 This demonstration is incomplete in many points of view. 
 In the first place, it is assumed that the stone falls by 
 attraction. In the next place, the moon being of one quar- 
 ter of the diameter of the earth, there is her reciprocal 
 attraction to enter as an element of calculation ; for the 
 attractive force of the stone and earth would not measure 
 the joint attractive force of the earth and moon. Her mass, 
 never to be ascertained, would influence the result. Again, 
 the resisting medium of the motion of the stone and the 
 moon may be different, making the fall and deflection of 
 different values for the same time. 
 
 But admit that the stone falls by attraction, that the 
 moon's greater mass does not vary the strength of the 
 attractive force, and that the media through which they 
 move are the same, the attraction for the stone is a con- 
 stantly increasing force, giving constant and uniform accele- 
 ration of motion, while the attraction for the moon is a stati- 
 cal force, bearing with uniform intensity or weight. Attrac- 
 tion for the falling stone is a cumulative energy. for the 
 moon a constant power. The moon is not drawn toward the 
 earth, but keeps the same orbit ; she preserves, so far as 
 relates to the force of gravitation, one distance. If two, 
 three, or four similar arcs be cut off, of two, three, or four 
 minutes, the aggregate of deflection will be found by the 
 simple addition of the deflection of each, the aggregate 
 
320 OUTLINES OF A SYSTEM OF 
 
 of the fall of the stone for two, three, or four seconds, will 
 be found by squaring the time, not by the simple addition 
 of the time. 
 
 If we take for one element of calculation an uniformly 
 accelerated velocity to be handled mathematically in com- 
 parison with an equable velocity, it must be motion for a 
 definite time, and the mean of this varying velocity must 
 be deduced as its measure or value ; for instance, take the 
 time of the fall of the stone equal to one revolution of the 
 moon, find the mean velocity, and compare this mean velocity 
 with the velocity of the moon in her orbit. Will a body 
 falling for the whole time of the revolution of the moon, 
 have a mean velocity equal only to the deflection of the 
 moon in one orbitual circle ? Even here there will be only 
 an approximation to a common standard ; for the true ele- 
 ment for calculation is the mean velocity of the falling stone 
 for the whole duration of time for which the moon has been 
 in motion. As the proposition has been demonstrated, the 
 result is true of one given arc of deflection, compared with 
 one second of the time and the resulting velocity of the 
 falling stone. The moon, if she were let go and fell to the 
 earth, would unquestionably obey the laws of falling bodies. 
 Her spare force of rotation would be in the same ratio 
 according to the change of level. Every line of her down- 
 ward motion would increase her velocity. Continuing in her 
 orbit, her motion is uniform, equable, ever the same, accord- 
 ing to her distance from her centre of rotation around the 
 earth or its axis. The two motions have no analogy ; there 
 is between them no ground of comparison ; the one is 
 equable, the other accelerated, the one is fixed, the other 
 without bounds, the one is incidental, the other perpetual. 
 They cannot be bound together in the same mathematical 
 
MECHANICAL PHILOSOPHY. 321 
 
 reasoning, save under the law of equal areas, and that by 
 which decreasing areas of motion give out the same force 
 that equal increasing areas of motion would require. 
 
 To combine them demands that a retarding element be 
 added to the one, or an accelerating element to the other, 
 and the degree or value of this new element cannot be math- 
 ematically expressed, since it involves the conception of an 
 infinite series. It plunges us at once into the depths of 
 transcendental mathematics. 
 
 Newton was aware of the incompleteness of the demon- 
 stration. He believed in a subtle ether which filled all 
 space, and which gave to the spheres a retarded velocity. 
 His disciples discarded the ether, and succeeding philoso- 
 phers adopted the bold and bare conception of gravitation, 
 which Newton thus expressly disavows in his often quoted 
 letter to Dr. Bentley. 
 
 " It is inconceivable," writes Newton, " that inanimate 
 brute matter should, without the mediation of something 
 else which is not material, operate upon and affect other 
 matter without mutual contact, which it must do if gravita- 
 tion in the sense of Epicurus be essential and inherent in 
 it, and this is the reason why I desire that you would not 
 ascribe it to me. It is so great an absurdity that I believe 
 no man, who has in philosophical matters a competent way 
 of thinking, can ever fall into it." * So even those may dis- 
 
 * On this subject, Stewart remarks in his Philosophy, " It is impossi- 
 ble to conceive, in what manner one body acts on another at a distance, 
 through a vacuum. But I cannot admit that it removes the difficulty to 
 suppose, that the two bodies are in actual contact. That one body may be 
 the efficient cause of the motion of another body placed at a distance from 
 it, I do by no means assert ; but only that we have a good reason to 
 believe that this may be possible, as to believe that any one natural event 
 is the efficient cause of another." 
 
322 OUTLINES OF A SYSTEM OF 
 
 card the attraction of brute matter most who revere the 
 name of Newton, those who are 
 
 "passionate for ancient truth 
 And honoring with religious love, the great 
 Of elder times," 
 
 are not compelled to adhere to a theory, which gives one 
 sphere a power over another sphere, at a distance from it, 
 without the mediation of something which is not matter 
 that passes between them. 
 
 It is not wonderful that Newton repelled almost indig- 
 nantly the imputation that he believed in the attraction of 
 brute matter ; but it is surprising that any man should have 
 a distinct conception of the harmony of the spheres, of their 
 equable unchanging velocities, of the fixed law of their 
 movements, and find in their uniformity an analogy with a 
 falling stone, between which motions there can be no rela- 
 tion whatever, no ratio of velocity, no common condition, 
 the one being permanent, the other incidental ; the one, as 
 it were the accident, the other the law of nature ; the one, 
 a flowing in a determined orbit, the other a passage from one 
 orbit of rotation to another orbit of rotation ; the one 
 bearing the stamp of perpetuity, the other being the evi- 
 dence of change ; the one continuous, the other enduring but 
 for a time. Equally surprising is it that any one can look 
 upward to the revolving spheres, in number exceeding the 
 sands of the sea-shore, all, every one, moving in curves ; 
 or look downwards, seeing there no straight lines of motion, 
 the smallest 'level of the earth to the eye of philosophy 
 being a curve, knowing that the straight line, wherever 
 drawn, would be a line of collision and impingement, and 
 yet affirm, that not one sphere for one moment could be 
 
MECHANICAL PHILOSOPHY. 323 
 
 held to the curve, without the conflicting force of gravitation 
 to overcome the natural rectilinear law of motion. 
 
 We have thus passed hastily over a vast extent of illus- 
 tration, and present this rough outline to the public eye. 
 We wish that it were more worthy of the subject, more 
 faithful to the idea that we have formed. 
 
 Not by way of apology, but to give the reason for it, we 
 will advert for a moment to our frequent recurrence to the 
 religious bearings of science, and to the Mosaic account of 
 the Creation. The association of this research with the 
 Bible, came early with the thought that in the instance of 
 the rainbow philosophy was but the echo of the voice of 
 God, and the connected passages were read with an in- 
 creased reverence and intense interest. 
 
 There is no man, however skeptical the usual frame of 
 his mind, however careless and worldly the usual train of 
 his thought, who does not at times look upward for support 
 and direction. Nor, in a scientific inquiry, when baffled in 
 the attempt to comprehend the works of Nature, when 
 tossed on the changing wave of theory, can the student 
 refrain from seeking light, direction, authority, from above. 
 The mind is so constituted as to look for some revelation 
 beyond what the face of nature presents. 
 
 Were the Mosaic account of the beginning but the fresh- 
 ness of philosophy, the earnest expression of the human 
 mind, when the earth in her early morning was first exam- 
 ined by man, were the ideas mere thoughts handed down 
 from the beginning of the world, mere traditions kept 
 pure and uncontaminated in the Bible, preserved from the 
 defilement of a passage through the minds of countless gen- 
 erations, like the pure waters of a mountain lake, clear 
 and sparkling in the light of heaven, because kept from a 
 
324 OUTLINES OF A SYSTEM OF 
 
 soiling channel, in this point of view, worthy is the tradi- 
 tion, how much more worthy to him who looks upon the 
 Bible as the word of God ! 
 
 In whatever point of view it may be considered, there 
 are strong expressions, there is a force of words, a striking 
 language in the first of Genesis, and if studied, not in verbal 
 criticism, but with a tone of mind in sympathy with its 
 spirit, there may be found light to show the construction of 
 the world and the nature of the elements of which it is com- 
 posed ; and light that will dissipate the mists of skepticism 
 which dim the beauty and glory of creation. 
 
 In conclusion, we ask for a few minutes' consideration of 
 the effect of mechanical theories of the universe on faith in 
 the superintending Providence of God. A blameless life 
 and the most fervent piety have often been associated with 
 manifest errors in philosophy ; and grievous faults and utter 
 indifference to religion have been accompanied by the most 
 eminent scientific attainments. Therefore a man's theories 
 should never be deemed the test of his religious character. 
 But, on the other hand, the effect of philosophical speculation 
 on the general mind, its tendency to aid in the formation 
 of the Christian character, or to produce a skeptical spirit, 
 is a proper subject of investigation. 
 
 There are no atheists now. No man avows his unbelief; 
 nor are there any theories put forth which do not recognize 
 the existence of the Great First Cause. A purely mechan- 
 ical theory of the construction of the world, the nebular 
 hypothesis for instance, acknowledges that God created the 
 material from which the worlds were constructed, and that 
 He gave to it its law, or mode of action. But this being 
 accomplished, the idea of God becomes an abstraction ; it 
 
MECHANICAL PHILOSOPHY. 325 
 
 is no longer a necessary part of the speculation. Matter has 
 been created, and it acts ; the machine has been constructed, 
 and it continues in operation. There is no need of a super- 
 intending Providence. Mechanism, the power of matter, 
 stands in its place. The sparrow falls to the ground because 
 of some material sequence. The earth is self-shaped and 
 self-sustained ; its relative position and motion are derived 
 from the action of other spheres upon it. A circle is thus 
 described around all material things, excluding God, yet 
 comprehending within its circumference all requisite power 
 for the self-preservation and self-government of matter. 
 Notwithstanding the chilling influence of this theory, a man, 
 from the original bias of his mind, from early education, or 
 by means of the written and spoken word, may retain his 
 faith ; but it is not a theory to convert the skeptical, con- 
 firm the wavering, or deepen the conviction of any mind. 
 Therefore, although science has enrolled among its votaries 
 the names of many men distinguished for their religious 
 faith, it has not been preeminent as it should have been, for 
 producing and confirming the religious character. 
 
 We believe that the ultimate test of the soundness of 
 theory in philosophy should be its religious bearing on the 
 character ; and that if any mechanical theory ascribes to mat- 
 ter power to shape for itself its masses, or to determine for 
 itself its position and motion, thereby enabling the mind to 
 regard creation without the idea of a present sustaining 
 God, it is not the true theory. True philosophy will do 
 more than merely to permit or tolerate a belief in God ; it 
 will compel the mind to trace all things directly and imme- 
 diately to Him. 
 
 The belief that the universe is a vast machine, in regular 
 constant action because of the inherent powers of matter, 
 
 28 
 
326 OUTLINES OF A SYSTEM OF 
 
 arises from a supposed analogy between the works of God 
 and of man. They ought not to be thus associated. The 
 means and processes of the mechanic are not the means and 
 processes of the Artificer of worlds. A steam-engine is 
 constructed ; the desired result is to control and change the 
 direction of the force of steam by means of the iron cylin- 
 der, of bolts and rods, of pipes and valves. The object is 
 to modify the action of existing force, and this is accom- 
 plished by using the known properties of matter, its elas- 
 ticity and force of cohesion. The engine constructed, the 
 mechanic stands aside, the spectator of its action. Thus 
 mechanical philosophy regards the world. God, by means of 
 the properties and laws of matter, has constructed a world, 
 and He then becomes only a witness of the action of the 
 perfect machine. But there is no analogy whatever be- 
 tween these processes, or their results. The artisan, by the 
 use of mechanical powers, by wheels, levers, and pullies, 
 seeks to control existing force, to change established mo- 
 tion. He works with the full understanding, that, in rela- 
 tion to him, there are fixed laws of force, and definite pro- 
 perties in matter. His command over matter comes from 
 the sequences established by a higher power. Not so with 
 God. Matter in relation to Him has no assigned quality, 
 no position derived from its inherent powers. It is clay in 
 the hands of the potter. Its only attribute is obedience, 
 and the form, position, motion given to it, its only possible 
 property. Where it is and what it is are from God. It 
 has no will of its own, nor is the Divine Artificer constrained 
 to apply the law which governs one form of matter to limit 
 the force of another form of matter. Hence to God there is 
 no machinery whatever. A planet is in its place, not by 
 any virtue or energy of its own, nor by the virtue or energy 
 
MECHANICAL PHILOSOPHY. 327 
 
 of any other sphere. It is whefe it is, and moves as it 
 moves, not by a mechanical power, but by a spiritual agency, 
 not by machinery, but by the will of God. One event 
 does not happen because of another preceding event, but 
 both from His will ; one thing is not the cause of another, 
 but all things are obedient. 
 
 There is no necessity, arising from inherent properties of 
 matter, that this earth should be the pleasant home of man. 
 Matter of itself cannot minister to human wants. There is 
 no absolute necessity that there should be the regulated 
 succession of phenomena, by which man traces out order and 
 design. There is no necessarily existing connection between 
 material cause and effect. All is from the direct and imme- 
 diate will of God. The natural sequences of things, the 
 regulated successions of events, are but ministrations to hu- 
 man weakness. The body has wants, and they are provided 
 for ; the mind desires knowledge, and the creation is brought 
 down as it were to the level of its comprehension. An 
 order is stamped upon the mind, and to this order, to this 
 low degree of comprehension, is the creation adapted. 
 
 A miracle declares the presence of God ; but the miracle 
 is only the sudden withdrawal of the veil which uniformity 
 of action spreads over the Supreme Power. And in one 
 point of view even the uniformity of God's Providence is a 
 miracle. For this very regulated succession, and these 
 apparently predetermined results, are the manifestation of 
 the Supreme Power as conformed to the intellectual wants 
 of the individual man. Every instance in which man traces 
 the conformity of one thing to another, every instance of the 
 discovery of order in the heavens or in the earth, is the 
 manifestation of the Divine attributes, which have so con- 
 structed the Universe and the soul of man, that the order in 
 
328 OUTLINES OF A SYSTEM OF 
 
 the one is the counterpart of the order in the other. In the 
 discovery of this order is the glory of philosophy and its 
 reward, and herein is philosophy taught to bring all its the- 
 ories to this ultimate test : Do they impress on the mind, 
 not the idea that there is power in matter, and that the uni- 
 verse is a perfectly constructed machine, but the great idea 
 of a Father in Heaven, w r ho condescends to the weakness 
 of his children, giving them not only day by day their daily 
 bread, but furnishing them, in the evidences of design con- 
 tinually displayed before them, the intellectual strength 
 which may lift their minds to Him ? 
 
 " How exquisitely the individual Mind 
 (And the progressive powers perhaps no less 
 Of the whole species) to the External world 
 Is fitted : and how exquisitely too 
 Theme this but little heard of among men 
 The External world is fitted to the mind ; 
 And the Creation (by no lower name 
 Can it be called,) which they with blended might 
 Accomplish this is our high argument." 
 
 We firmly believe that in the progress of time there will 
 remain no mechanical theories of the construction or of the 
 preservation of the universe. Does matter by delegated 
 power, or does God directly determine the place and posi- 
 tion of all things ? One or the other is the case ; there is no 
 divided sway. The universe is a machine with a far-off 
 God ; or the present God sustains, upholds, moves every 
 part, and this, not from a law impressed upon matter from 
 the beginning, but because matter has no quality, attribute, 
 or power of its own. It but obeys His present will. 
 
 We have attempted to form some definite idea of 
 power, of force, of something which exists independently 
 of matter, which is not a property of matter, and which 
 
MECHANICAL PHILOSOPHY. 329 
 
 matter can never wield or direct. We ascribe to the ma- 
 terial of creation no power of self-direction or self-control. 
 We believe in power, because we are conscious of exercising 
 it in some degree through the will, by which we can change 
 the position and motion of things. We compare our feeble 
 strength with the force of the elements, and this with 
 the intensity of the motion of the world, and this again with 
 the majestic movements of the extended system of worlds. 
 Nor will the mind pause here ; it goes at once to the omni- 
 potence of God. The acknowledgment that the power which, 
 proceeding from human volition, acts directly on matter, 
 is something which is independent of matter, born of the 
 will and not generated by mechanism, is the first step in 
 progress. Comparing this in its utter insignificance with 
 the power which moves the great universe, knowing as we 
 must know that this force can proceed only from mind, we 
 are led upward till we reach the Source of all power. 
 
 We look upon the universe as the creation of God, set 
 forth as the symbol of His wisdom, as His thoughts writ- 
 ten out in matter. We are not willing to assign to matter 
 that which is not, and which never can be its property, or 
 to degrade the spiritual into a pantheistic commingling with 
 the material. We cannot conceive of a universe without the 
 idea of the Creator, nor of a universe that can contain God, 
 or be of sufficient extent or value to give scope for the attri- 
 butes of the Omnipotent. We have no sympathy with the- 
 ories which present the idea of a gradual induction of order 
 from confusion, of a waiting for completeness, of extended 
 time as requisite to bring about the desired results. We 
 love to think that the worlds came perfect from the hands of 
 their Creator, and that all their changes are but from one 
 perfection to another perfection, without a gradual process, 
 
330 OUTLINES OF A SYSTEM, ETC. 
 
 without an intermediate confusion. We believe not in a 
 time when the world was not clothed with perfect wisdom as 
 its vesture. We hold that philosophy to be the most true to 
 the actual construction of things, which most clearly estab- 
 lishes these ideas in the mind. We like to discharge the 
 words, nature, law, regular succession, and the like, and to 
 ascend at once to that which they indistinctly represent, 
 to the idea of " that pure and holy Mind that with swift 
 thoughts agitates the whole world." Why should we confine 
 ourselves to language which gives the idea of intervening 
 powers, and which thus separates the Deity from His works ? 
 The word nature is but a substitution, the word law is 
 but the obscured representation of Omnipresence, order, 
 regulated succession, mean Omniscience, adaptation, har- 
 mony, " the agreeable fitness of things," vaguely present 
 the idea of a Father in Heaven. 
 
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