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Tethod of separate Tanch.-This was adopted by Knight in straight line (fig. 371). The bundle represented in fig. 373 i: this country in 171.5 , and consis's in placing the two contrary formed of five plates of steel placed side by side, that in fig

. wish to magnetise, and making them both slude simultaneousla four plates in each. The form of the horse-shoe is preferabl : towards one of the ends of the bar, holding them vertically. Eich magnet is then brought back tie middle of the bar, and

Fig. 374. the operation is repeated several times on bith sides till the bar is magnetised." Duhamelimproved this neirol by placing the two eniis of the bar to be magnetised the contruy poles of two final magnets, whose action combines with that of the moveable magnets, the relative position ef the piles being the same as in lin. 372. This process gives the most steady magnetic power.

Met hand cr Detais -- In this meh 1, introduced by for supporting a weight by means of the magnet, because use Mitchell, the two regrets en pored in friction are still placed is made of both poles at the same time. The magnetic power at the middle of the bar we wish to mana tise, with their of a bundle is not equal to the sum of the separate forces of contrary poles towards each other; ta med of sliding the bars, owing to the repulsive action of neighbouring poles towarus its extremsies in contrarts, they are kep at upon one another. a certain distance ran ::: Tostal piece of wood Armatures or Keepers of magnets, are the pieces of soft iron placed between them?

fr in the middle to which are placed in contact with the poles, to preserve or one extremity, the:

Tetiremity, and so on increase the magnetic power. Fig. 375 represents a natural in such a manner thai ::8.

trundergoes the same magnet with its armatures. On the surfaces corresponding to number of three : TS.

served that in the the poles are two plates of soft iron, each terminated by a varius processes is 1876. magrets, Jose none of massive block. Under the influence of the natural magnet theur part, ws: Encarte fluids do not pass these plates become magnetised, and the letters A and B reprethum inc ba: te

senting the position of the poles of the natural magnet, it is in F. 1.-The action of the easy to see that those of the armatures are respectively repreestih name ringte si dang similar to that of | sented by ab. Now these armatures, when once they are

Fig. 372.

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mech oppassen constantly tends to separate the magnetised, react in their turn upon the neutral Auid of the

a neutral state in soft iron and steel, ' natural magnet, decompose it, and thus increase the magnetic
mirce, the coercive force being very power. Without armatures, natural magnets are very feeble,

is earth is insufficient to produce mag. but with them they become capable of sustaining weights which His with a bar of soft iron, especially if it

Fig. 375. OP ; hte meridian parallel to the inclination.

unsteady sort of magnetisation. mis en Arendtitre 8 of Magnete. -A magnetic Down ***on of magnetised bars united parallel to

Sometimes it is nach war at their poles of the same name. made in the shape of a horse-shoe (fig. 373), sometimes of a

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Fig. 373.

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till they have reached a certain limit that is never passed. The substance supported a' b', which is of soft iron, acts as a second armature, for being magnetised by induction, its poles a' and b' react upon the poles a and 6 of the former. To furnish artificial magnets with armatures, place them in pairs, as represented in fig. 376, with the contrary poles opposite each other; then put iwo small bars of soft iron A B in connexion with the poles, these becoming magnetised by induction, their poles react upon the magnetised bars and preserve their intensity. As for moveable needles (figs. 362 and 365) as they turn towards the magnetic poles of the globe, the influence of this latter acts as an armature.

B

Law of Magnetic Attraction and Repulsion.—Coulomb was the which the micrometer has been turned, represents the total first who established the law, that magnetic attraction and torsion of the thread. repulsion is inversely as the square of the distance, a principle In the experiments made by Coulomb, this number was which he established by two methods, that of the torsion 35, but it varies with the length of the thread, its balance and that of oscillations.

diameter, and the intensity of the bar a B. Now the needle

remaining at present in equilibrium, it is evident that the Fig. 376.

force of the torsion of the thread is precisely equal and opposite to the directing influence of the earth. This action, then, in the experiments of Coulomb was represented by 35 for a deviation of one degree; but the force of torsion being proportional to the angle of torsion (vol. iv. p. 101), and the directing action of the earth, when there has once been equilibrium, being equal to it; it follows that this latter force, for the deviation of 2°, 3°, etc., is represented by twice, three times, etc. 35 degrees.

The action of the earth being determined, put the magnet a b Torsion Balance. This apparatus consists of a glass box (fig. into the box, taking care to put poles of the same name 377), with a glass cover capable of being removed at pleasure, opposite each other. The pole of A of the needle is then and having an opening near the edge to admit a magnet ab. repelled, and if x represent the number of degrees which In the centre of this cover is a second opening, into which a measure the angle of deviation when the needle A B is in glass tube is fitted so as to turn with slighe friction against the equilibrium, this needle tends to return to the magnetic edges of the orifice. This tube has in the upper part of it a meridian with a force represented by n + 35 n, the part n micrometer, or combination of two pieces, one of which D is being due to the torsion of the thread, and the other part 35 N fixed and divided round its edge into 360 degrees, and the to the action of the earth. But since it does not return to the other e which is moveable, has graduations marked on magnetic meridian, the repulsive force exercised between the it, to show the number of degrees through which it is poles a ar! A must be itself equal to n + 35 n. Now turn the turned on the dial-plate d. On the left of the figure at c disc E in such a way that the angle of deviation n may become and d the two pieces which constitute the micrometer are half what it was. According to the position of the needle A B represented a large scale. To the disc e are affixed two in the accompanying figure, it would be necessary to turn it uprights, through which passes a horizontal axis. Upon this from right to left. Representing the displacement of the disc axis a very fine silver thread is wound, supporting a magnetised E by n, we see that the suspension thread is twisted n degrees

to the left at its upper end, and Fig. 377.

degrees to the right at its 2

N

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N lower end, consequently its whole torsion is n + Therefore

2 the real force which tends to bring back the needle to the magnetic meridian is (" n+*) **,- + representing

35 x the force of torsion, and the action of the earth. Now,

2 as the needle does not return to the meridian, the repulsive force between the two poles a and A must itself be represented

35 N

by m + poproting

2 2 Substituting for n and N the numbers supplied by experi

3.1 x ment, we find that the quantity nt + is precisely the

2 2 quadruple of the quantity n + 35 n obtained by the first experiment. Therefore the law of Coulomb is demonstrated, for experiments are made with arcs, n and so small as to be

2' needle A R. Lastly, at the bottom of the box is a dial-plate with divisions to measure the displacement of the needle A B nearly equal to their chords, that is to say, that when the arc and

consequently the torsion of the silver thread, or the force is bisected, a a, the distance between the two poles is also with which it returns to a state of rest.

apparently bisected. The index a of the disc e being at zero on the dial d, the

Method of Oscillations. This consists in making a magnetised box is placed in such a manner that the centre and the zero needle oscillate in equal times, first under the sole influence of the lower dial-plate may be in the magnetic meridian. of the earth, and then under the combined influence of the Then, taking the needle a's away, replace it by a similar earth and the attracting pole of a magnet placed at two needle made of copper or any other non-magnetic metal. Turn unequal distances one after the other. the glass tube, and with it the pieces B and p in such a way numbers of oscillations observed, the law of Coulomb may be that this needle may stop at the zero point of the lower dial deduced by calculation. plate. The magnetised needle not being yet inserted, remove Measure of Terrestrial Magnetism.--A great number of philothe non-magnetic needle, and put the magnetised needle A B sophers and navigators have employed themselves in measuring in its place, which will then be exactly in the magnetic the magnetic intensity of the earth in different places and at meridian, and the torsion of the silver thread is null.

different periods. Several methods have been adopted, which The apparatus being thus arranged, it is necessary before consist in making a needle of inclination or declination oscillate introducing the magnet a b to know the action of the earth for a given time, and then deducing the relative intensities upon the moveable needle A B when it is a certain number of from the number of oscillations. Their observations have led degrees out of the magnetic meridian. For this purpose, turn to the establishment of the following laws. the piece e till the needle

A B is moved one degree in the 1. The intensity of the earth's magnetism increases as we same direction. The number of degrees minus one, through | recede froin the equator, and it appears to be half as great

Method of Separate Touch.-- This was adopted by Knight in straight line (fig. 371). The bundle represented in fiz. 37
this country in 1745, and consists in placing the two contrary formed of five plates of steel placed side by side, that in ...
poles of two bars of equal intensity at the middle of the bar we 374 consists of twelve plates arranged in three layers
wish to magnetise, and making them both slide simultaneously four plates in each. The form of the horse-shoe is fre'
towards one of the ends of the bar, holding them vertically.
Each magnet is then brought back to the middle of the bar, and

Fig. 374.
the operation is repeated several times on both sides till the
bar is magnetised. Duhamel improved this inethod by placing
the two ends of the bar to be magnetised at the contrary poles
of two fixed magnets, whose action combines with that of the
moveable magnets, the relative position of the poles being the
same as in fig. 372. This process gives the most steady
magnetic power.

Method of Double Touch.-In this method, introduced by for supporting a weight by means of the magnet,
Mitchell, the two magnets employed in friction are still placed is made of both poles at the same time. The mig
at the middle of the bar we wish to magnetise, with their of a bundle is not equal to the sum of the sepi
contrary poles towards each other ; but instead of sliding the bars, owing to the repulsive action of neigh').
towards its extremities in contrary directions, they are kept at upon one another,
a certain distance from each other by a small piece of wood Armatures or Keepers of magnets, are the pic
placed between them, and slide together from the middle to which are placed in contact with the polex,
one extremity, then from this to the other extremity, and so on increase the magnetic power. Fig. 375 repris
in such a manner that each half of the bar undergoes the same magnet with its armatures. On the surfaces,
number of these operations. It is to be observed that in the the poles are two plates of soft iron, eachi
various processes of magnetisation the magnets lose none of massive block. Under the influence of the
their power, which proves that the magnetic fluids do not pass these plates become magnetised, and their
from one bar to another.

senting the position of the poles of the 1;"
Magnetisation by the Action of the Earth. The action of the easy to see that those of the armatures ar
earth upon magnetic substances being similar to that of sented by ab. Now these armatures, TM

Fig. 372.

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magnets, terrestrial magnetism constantly tends to separate the magnetised, react in their
two fluids which are in a neutral state in soft iron and steel. natural magnet, decom
But in the latter substance, the coercive force being very power. Without arm.
great, the action of the earth is insufficient to produce mag. but with them they by
netisation. It is not so with a bar of soft iron, especially if it
is placed in the magnetic meridian parallel to the inclination.
Yet even this is only an unsteady sort of magnetisation.

Magnetic Bundles. Armatures of Magnets.-A magnetic
bundle is a collection of magnetised bars united parallel to
each other at their poles of the same name. Sometimes it is
made in the shape of a horse-shoo (fig. 373), sometimes of a

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ced. When we think of that liberty
Le agency, and to the performance of
kind of liberty which we have in our
the inoral quality of an act, we never
ick than the spontaneous inclination of
rink it necessary to know in what way
quired. If the action proceed from
is concerned it is a moral act. We
great:r or more desirable liberty than
atures, indeed, cannot possess that inde-
h is the prerogative of the Deity. The
ding his liberty, is still under the govern-
idence.
int that we entertain distinct and accurate
ity which is inconsistent with free agency
as been termed moral or philosophical
is not incompatible with human liberty.
*han the certain operation of moral causes,

effects, according to the power which they
ecessity, it has been shown, must belong to
e cannot act in opposition to truth, wisdom,
. It this does not hinder him from acting freely.
in heaven and glorified saints are so confirmed

they cannot sin; but still in loving and serving
most freely.
the common use of terms, and according to the
prehension of men, liberty and necessity are dia-
pposite; when the name necessity is applied to
+, the prejudice immediately arises that it cannot
-pecially if there be some points in which it coin-
1 real necessity. Here, it is probable, we have the
urce of the difficulty and perplexity in which this
nas been involved. The word necessary should never
en applied to any exercises which are spontaneous or
ary, because all such are free in their very nature.
11 we apply this term to them, although we may qualify
calling it a moral or philosophical necessity, still the idea
rally and insensibly arises, that if necessary they cannot
free. It is highly important not to use a term out of its
roper signification ; especially when such consequences may
arise from an ambiguous use. An event may be absolutely
certain without being necessary. It was absolutely certain
that God, in creating the world, would act most wisely. It is

a matter of absolute certainty that the holy angels will con-
wut (tinue to love and serve God incessantly; but this certainty is

not inconsistent with liberty, If a man possess good prinlf

ciples, and all temptation to do wrong be removed, it is in

morally certain that, in any given case, he will do right; and

if a man be of corrupt principles, and all virtuous considera-
funda-

tions be foreign from his thoughts, and strong temptations be
presented to his ruling passion, it is certain that he will yield
to temptation and commit sin. But in all these cases there is

no necessity, because there is no coercion or compulsion. If
TY.

the mere certainty of an event were inconsistent with freedom,

then there could'be no such thing as liberty in God or the it to satisfy us,

creatures, As God knows all things most certainly, every adduced ; yet it thing, in his view, whatever may be its cause, is equally cerd, there are any tain; the divine prescience cannot be mistaken. There is ucy of man. It is no good reason why uncertainty should be considered essential sposition to any other to that liberty which is necessary to moral actions. All reason and the evident causes operate according to their nature and force.

The erience seem to stand in reason why one effect is necessary and another free is, not that arise from some misappre- the one takes place without an adequate cause, or that the or understanding is given us

same cause may produce different effects ; for both these are
-, no proposition clearly per- contrary to common sense. The true reason is, that the one
itively or by ratiocination, can is produced against will, or without will, whereas the other is
er truth.

a voluntary act.
refore, in the first place, to have Let the distinction between what is certain and what is

neant by liberty, and what by necessary be fully comprehended and attended to, and a great
'nce must be, not to metaphysical part of the darkness which, in the view of many, has obscured
inon judgment and clear conviction this subject will be dissipated. Although, then, it should be
it has already been stated that that demonstrated that the will is as certainly governed by motives
sary to moral agency, can be nothing as the scale of the balance is by weights, yet there can be no
of doing what we will, to the extent of legitimate inference from the one to the other, as if that would
reedom of action in conformity with our prove that the will is not free but under a necessity. The
Vhen a man is compelled by force to strike difference lies, not in the difference of certainty in the two
a not by the force of strong motives, but by cases, but in the difference in the nature of the causes of that
force), we say he is not accountable, because I certainty:

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again at the poles as at the equatorial line; consequently, the not be a moral act. Here we have a second circumstance or
line without inclination is also that of the least intensity: characteristic essential to moral agency, namely, that the

2. The magnetic intensity of the earth decreases as we riee action be voluntary. No involuntary action can be of a moral
in the atmosphere, and this decrease is probably according to nature.
the law that the force is inversely as the square of the Some distinguish the liberty of the agent from voluntari.
distance,

ness, but to us they appear to be the same, or to involve one 3. The magnetic intensity of the earth varies with the another. If an act is voluntary, it is free; and if free, it must hour of the day, being least between 10 and 11 in the morning, be voluntary. The highest conceivable degree of liberty in a and greatest between 4 and 5 in the afternoon.

dependent being is the power of doing as he wills or pleases. 4. The magnetic intensity exhibits icregular variations, and, But as this subject has by metaphysical controversy been like the inclination and declination, is subject to perturbations involved in perplexity, something may be said hereafter from the influence of the aurora borealis,

respecting what is called the freedom of the will.

When it is said that the actions of moral agents are the only proper objects of moral approbation or disapprobation, two qualifications of the assertion must be taken into view.

The first is, that the omission to act when duty calls is as LESSONS IN MORAL SCIENCE. -VO. IV.

much an object of disapprobation as a wicked action. Should

we see a number of persons sailing on a river in a boat, and MORAL AGENCY, AND WHAT IS NECESSARY TO IT. while we surveyed them, should a child near them fall into

the river, and no hand be stretched out to rescue it from As actions of moral agents are the proper and only objects drowning, we could not help feeling a strong disapprobation of moral approbation or disapprobation, it becomes necessary of the conduct of the persons who were near enough to render to institute an inquiry into the nature of moral agency or the necessary help. If, however, it should be ascertained into what are the constituents of a moral agent. The deci, that one or more of the persons were fast bound and pinioned, sion of this question must depend entirely on experience, and so that they could not possibly stretch out their hands to can never be determined by reasoning on abstract principles. rescue the child,

we should exempt them from all blame . for The process is simply this: we contemplate a great variety of no man is bound to do what is physically impossible. The acts, which by the moral faculty we judge to possess a moral second qualification of the statement is, that when we discharacter. We next examine the circumstances in which approve an external act, we always refer the blame to the those acts were performed, and we conclude those things motive or intention. But if we have evidence that the agent which are found in all of them to be necessary to moral possesses a nature or disposition which will lead him often or agency. Or, to render the examination more simple, we may uniformly to perpetrate the same act when the occasion shall suppose some one condition of the action to be absent, and occur, we not only censure the motive, but extend our moral then another, and then viewing the action as thus changed in disapprobation to the disposition or evil nature lying behind. its circumstances, we may bring it before the mind, and if the

If we suppose the case of an agent acted on by a superior moral quality of the act appear unchanged, we conclude that that which has been removed from it is no essential circum- power, so that the nature and direction of the act depend not

upon the agent himself, but upon the power by which he is stance in moral agency. But if the change in the circumstances governed, we shall consider the immediate agent as not free, of the action leads all men to take an entirely different view and the acts brought forth as not properly his acts, but those of its nature, then we conclude that this circumstance is essen

of the governing power. A demoniac or person possessed by tial to moral agency. To illustrate this principle, let us

an evil spirit who had power to direct his thoughts and suppose the following case: If we see a man suddenly, without govern his actions, would not be an accountable agent. any apparent provocation, raise his hand and strike another,

There are some who maintain that all human actions proceed believing that it was freely done, by a man compos mentis, we from God, as their first cause, and that man can act only as feel a strong disapprobation of the act, as immoral and he is acted upon. Upon this theory, it does not appear how deserving punishment. But if on inquiry it is ascertained man can be an accountable moral agent; for though his actions that the person who committed the assault was utterly desti- may be voluntary and performed in the exercise of reason, yet tute of reason, we may blame his keepers or friends

who left as he does not originate them, they can scarcely be considered him at liberty, but we no longer feel any moral disapproba- his own. tion of the act. For it is the intuitive judgment of all persons,

We will now suppose the case of a man possessing reason, that a man destitute of reason is not a moral agent, nor freedom, and will, and originating his cwn actions, but destiaccountable for his actions, whatever evil may be produced. tute of a moral faculty, or unable to perceive a difference We consider such a man as exactly in the same predicament between right and wrong. Can such a person be considered as a wild beast which does an injury. This is the common judgment of men; for in all courts of justice, when a man is of reason he may possess-who has no perception of moral

a moral agent? We think not. That being-how much soever arraigned for an assault

, if it can be proved that he was a relations, and no feeling of moral obligation, would be incamaniac at the time, he is acquitted, and all men approve the pable of a moral law, or of performing moral acts. judicial decision which exempts him from punishment. case is an imaginary one. There are, I believe, none who Hence it is apparent that the exercise of reason is essential to possess reason, and yet are destitute

of all moral sense ; but moral agency.

We may bring before our minds a thousand though we conceive of the intellect of a dog or an elephant acts, under different circumstances, but all performed by increased to any degree, yet, as being destitute of a moral agents without reason, and no man can believe that such faculty, we do not regard them as moral agents. actions are of a moral nature, or of good or evil desert.

It may seem to be an objection to this broad assertion that there are some who entertain the opinion that infants are

MAN A MORAL AGENT. moral agents from their birth, and commit actual sin. But these persons do not suppose that an irrational being can be

Very few have entertained the opinion that man is a mere a moral agent, but they think that infants have an obscure machine, governed by physical influences. It will not be exercise of reason. Their mistake is not in the general prin- necessary, therefore, tò occupy time in refuting an opinion ciple which has been laid down, but in the fact that infants contrary to reason and universal experience. have reason in exercise.

But there are many who entertain the opinion that man is Again, let the case supposed be varied. Let it be that the the creature of necessity; that in the circumstances in which person committing the assault had the full exercise of reason, each man is placed, he could not be different from what he is. but that the stroke was not voluntary, but the effect of a This theory of fatalism is plausible, becauee a slight observar spasmodic

, diseased, action of the muscles; or that the hand tion of the history of man shows that the moral characters of was moved by another. Every one, at once, judges that the most men are formed by the ed.ication which they receive, and person giving the stroke, whatever he might be in other by the sentiments and conduct of those with whom they assomatters, was no moral agent in this assault. It was a mere ciate. It has, therefore, been maintained—and the opinion physical operation, and not proceeding from the will, could | has in our day been industriously propagated that man is no

But the

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