Chapter X: Appendix: On the temperature of the earth anciently (2)

We arrive at the same conclusion in case of _friction_. It
is well known that pieces of wood can be made to _blaze_ by
rubbing them together. But it is not so well known, that two
pieces of rock crystal, or quartz, taken from any depth in the
earth, and which cannot be supposed to have ever been in the
light of the sun, when rubbed quickly together, even _under
water, will give out volumes of light_. _Whence_ this light?
from the quartz doubtless. Of course it must have been in a
latent state, and was set free by friction. Let it be strictly
observed, the crystals _never were exposed to the light of the
sun, of course could not have derived this light from that
luminary_.

We must come to the same conclusion, in regard to the light
given out by _animal_ substances. Many _insects_ are known to
have the power of evolving light, or putting the surrounding
luminiferous ether in motion, which is the same. Putrescent
animal matter has been observed to possess it, in some cases,
in a very great degree; sufficiently to illuminate a room, or
pantry, for hours together. In some instances the fingers of
those who touched the luminous flesh, became luminous.

This is eminently the case in regard to some fishes. A
species of fish called PHOLAS, has the power of evolving a
large quantity of light. This power is greater when the fish is
sound and fresh. Pliny mentions this fish, and says it rendered
the hands and clothes of persons luminous. When put in water,
under proper circumstances, it renders the water luminous. But
when put in milk, a single _pholas_ made seven ounces of it so
luminous as to enable one to distinguish the faces of persons
present. _Ency. Brit. Art._ LIGHT.

The evolution of light from the sea in the night, is a fact
of common observation, and is sometimes so great as to enable
one to read large print on a ship’s deck. _Ency. Brit. Art._
LIGHT.

In all the above instances, and many more might be added,
the light evolved, or, (which is the same thing in this
investigation,) the luminiferous ether put in motion, must have
been in a state of combination with the substances from which
it was evolved. The only question which remains is this: _Was
all this light transmitted from the sun, and become latent and
combined at the earth’s surface by absorption?_

It would certainly be hazardous to answer this question in
the affirmative. For how could we account for the evolution of
light from those bodies which have never been subject to the
sun’s influence?

Again: If all this light had been transmitted from the
sun, it will inevitably follow, that there was a time when
the quantity of light at the surface of the earth, and in
combination with terrestrial bodies, _was very small_, and of
course combustion, friction, and compression of bodies produced
anciently a much smaller quantity of light than now; because
there was a smaller quantity in combination.

It is evident that this supposition would come to this
conclusion: _The quantity of light, in combination at the
earth’s surface, has increased in the same ratio as the
increase of the duration of the influence of the sun on the
earth: and, by consequence, the quantity of light produced by
artificial means has increased in the same proportion._ Of
course, fires and candles burn more brightly now than they did
five thousand years since.

Though this conclusion is legitimate from the foregoing
supposition, yet it is at war with common sense, and the
current observations of the world.

We are therefore compelled to conclude that the MATTER _of
light_ is diffused throughout the universe, as is caloric, and
that it is evolved, or put in motion by the influence of the
sun; as also by artificial and chemical means; as combustion,
compression, friction, chemical action, &c.

This conclusion is much strengthened by the fact, that the
_existence of caloric_ is well ascertained, _not as proceeding
from the sun_, but in combination with all terrestrial
substances; and also by the fact of the constant _analogy_
between the phenomena of light and heat. This analogy is so
strong and striking that we are compelled to conclude, _if
heat be the effect of a real substance, light must be also_.
Indeed the analogy is so strong that it almost convinces us of
the _identity_ of the matter of heat, light, electricity, and
galvanism.

Notwithstanding the amount of evidence is against this
supposition at present, yet there is a strong tendency in
recent philosophical experiments to confirm it; and I am
inclined to believe that future discoveries will confirm this
identity. Some of the most obvious evidences in favor of it may
be introduced here.

1. Almost all the celebrated authors and experimenters have
occasionally _suggested_ the probability of this identity.
Mr. Turner, Elements of Chemistry, p. 67, says, in reference
to heat and light: “It has been supposed that _they are
modifications of the_ SAME AGENT; and though most persons
regard them as independent principles, yet they are certainly
allied in a way which at present is inexplicable.” Again,
p. 71. “Mr. Leslie conceives that light when absorbed, _is
converted into heat_.” Dr. Henry (Art. Light,) says, “A new
fact has been lately ascertained by Dr. Delaroche, which seems
to point out _a close connection_ between heat and light,
_and a gradual passage of the one into the other_. The rays
of _invisible_ heat pass through glass with difficulty at a
temperature below that of boiling water; but they traverse
it with a facility always increasing with the temperature,
as it approaches the point at which bodies become luminous.”
“The general facts, says Sir H. Davy, of the refraction and
effects of the solar beam, offer an analogy to the agencies
of electricity.” (_Ure, Chemical Dictionary, Article Light._)
It is well known that this view pressed itself strongly on
the attention of Sir Isaac Newton, during his philosophical
investigation. _See Ure, Chem. Dic. Art. Light._

2. This identity is strongly suggested by the constant and
striking analogy between the laws of heat and light.

_First:_ The color of surfaces has an influence on the
passage of light and heat.

_Secondly:_ The power of light, heat, and electricity
diminishes as the squares of their distances.

_Thirdly:_ The particles of heat, light, and electricity,
are _idio-repulsive_.

_Fourthly:_ The passage of the electric spark is generally
attended with the production of light and heat.

_Fifthly:_ Heat is emitted in all directions from the
surface of an ignited body: so is light from the surface of a
burning body.

_Sixthly:_ The laws of reflection are the same in light and
heat.

Other coincidences might be established, and other
celebrated names added.

If this identity should be established finally, it would
not effect the doctrine of the foregoing pages in the least. It
would only be necessary to say, the luminiferous fluid of this
essay is the well established substance now called caloric.

_Addenda on Light._

1. It is now generally admitted that the real body
of the sun is surrounded with a peculiar set of clouds,
_phosphorescent_ in their nature. It is also allowed that these
clouds do not emit heat. And as it is well known that no one of
the _planets_ has such clouds, but receive their light from the
sun, _it is extremely probable that these phosphorescent clouds
are intended by the Creator, to be the great dispenser of light
to the solar system, by operating as the exciting cause to put
the luminiferous ether in motion throughout the solar system_.

By a parity of reasoning, each centre of a system may be
invested with similar clouds, which operate in the same way in
reference to the planets which belong to it.

2. If light were a real substance, _as commonly
understood_, solar light must proceed from the sun by
_impulsion_, and artificial light from burning bodies by
_evolution_. Take the case of burning bodies. A single candle
placed two miles above the surface of the earth in the air, and
lighted up in that position, will _instantly illuminate a space
of two miles in every direction from itself, or a spherical
space four miles in diameter_. In this case a sufficient
quantity of light is instantly evolved to fill this space,
and the evolution continues as long as the candle burns. The
question upon this fact is this: Can it be supposed that there
is a sufficient quantity of light, in combination with a single
candle, or the oxygen necessary to keep up its combustion, to
fill a spherical space four miles in diameter for several hours
together? This would indeed be almost incredible in view of the
space filled by light evolved from a single candle.

But this difficulty would be satisfactorily solved upon
the supposition that light is the _effect_, produced by a
luminiferous ether, universally diffused, and put in motion,
by which it becomes visible, by the sun, burning bodies,
&c. Because, the motion which renders the luminiferous
ether visible, commences instantly upon the commencement of
combustion, and is propagated from the point of combustion _in
right lines_, under the appearance of rays of light: but the
motion ceases instantly on the cessation of combustion, and of
course darkness instantly ensues.]

After having attended to the production of _light_, and noticed some of its properties, it is a paramount duty to contemplate its glorious Author; especially as by this mysterious production he himself has chosen to be represented. If creatures be excellent, what must be the Creator? and to admire the former without adoring the latter, would be profane and atheistical. “The Deity,” says Sir Isaac Newton, “in infinite space, as in his own _sensorium_, has an intimate perception of all things:” so we, possessing intellect, should “look through nature up to nature’s GOD.” Then matter, however rarefied or diversified, would serve as his minister to introduce us into his presence. A pious ancient, on being asked by a profane philosopher, How he could contemplate high things, since he had no books? answered, That he had the whole world for his book, ready open at all times, and in all places, and that he could therein read things heavenly and divine. As the visible creation is the outward expression of the existence of God, and displays several of his infinite perfections; so we should study him in the works of nature, and trace him in the operation of his hands.

The late excellent and pious Bishop Horne very beautifully observes,--“When the angels beheld the dark and disordered state of created nature upon its first production, they were, doubtless, thrown into some perplexity to conceive how it should ever be made a means of manifesting forth the glory of the Creator. But when they saw the light spring up, at the Divine command, from that blackness of darkness, and fix its residence in its tabernacle the sun, illuminating and adorning the firmament of heaven with its glorious show, and the earth with its beautiful furniture, all formed out of rudeness and confusion, then they confessed that the difficulty of the work served only to display the skill of the workmaster, which is proportionally estimated by the unpromising nature of the materials.

In like manner, whoever views the chaos to which the infinite wisdom of a presiding Providence sometimes permits the moral world to be reduced by the prevailing power of the prince of darkness, and the agency of his instruments, will scarce be able, at first, to discern any traces of the Divine counsels in a mirror so sullied and clouded over by the enormities of sinful men. Yet let him wait with patience for a little season, and those clouds shall pass away; a light shall shine, and some great end present itself to sight, so worthy of God, so beneficial to man, that standing amazed at a power able to bring the greatest good out of the greatest evil, he will be forced to cry out concerning the economy of the spiritual system, as David did concerning the operations of the natural--‘Oh Lord, how manifold are thy works! In wisdom hast thou made them all.’”[46]

* * * * *

_Section_ IV.--DAY AND NIGHT.

Original terms of Day and Night -- Motion the effect of
a Divine power -- Commencement of Time -- Utility of Day and
Night -- Religious improvement of Time -- Sin moral darkness --
The Gospel a Light to dispel it -- A Christian the subject of
a transition from the one state to the other.

The separation of _light_ from the _darkness_, was the work of the _first day_. This was an arrangement made by infinite Wisdom, as well as a display of almighty power. When this took place, it is highly probable that God gave to the earth its rotation upon its own axis, to produce the necessary succession of _day_ and _night_. “The word ערב _éreb_, which we translate _evening_, comes from the root ערב _ârab_, to _mingle_, and properly signifies that state in which neither absolute darkness, nor full light, prevails. It has nearly the same grammatical signification with our _twilight_, the time that elapses from the setting of the sun till he is eighteen degrees below the horizon, and eighteen degrees before he arises. Thus we have the morning and evening twilight, or _mixture_ of light and darkness, in which neither prevails; because, while the sun is within eighteen degrees of the horizon, either after his setting, or before his rising, the atmosphere has power to refract the rays of light, and send them back to the earth. The Hebrews extended the meaning of this term to the whole duration of night, because it was ever a _mingled_ state; the moon, the planets, or the stars, tempering the darkness with some rays of light. From the _ereb_ of Moses came the Ερεβος _Erebus_ of Hesiod, Aristophanes, and other heathens, which they _deified_, and made with _nox_, or night, the parent of all things. The word בקר _boquer_, which we translate _morning_, from בקר _boquar_, he _looked out_, is a beautiful figure, which represents the morning as _looking out_ at the east, and illuminating the whole of the upper hemisphere.”[47]

All bodies continue in a state of rest, till they are put into motion by some external force impressed on them. Motion is the removal of a body from one place to another, or a continual change of place.[48] Any force acting on a body to move it, is called a _power_. The _momentum_, or quantity of motion, is in proportion to the force impressed. The heavier any body is, the greater is the power required to move it.

There are but three possible ways of accounting for motion:--either by supposing that there has been an infinite succession of impulses communicated from one body to another from eternity, without any active principle either in matter or without it: or, that there is an active principle in matter that renders it self-active, and motion essential to it: or, else, that there is a Being distinct from matter, and is the cause of its motion.

An infinite succession of impulses, without an active or moving principle, will never give birth to motion, because this would be to produce an effect without the assistance of a cause. This absurdity was asserted by Spinosa; yet when urged by his friends to explain how matter could ever come into motion, if motion was neither essential to matter, nor proceeded from any external cause, he always avoided giving a direct answer. This conduct makes it reasonable to believe, that he himself would have given up his account of motion, if he could have saved his atheistical scheme and his reputation.

That motion is essential to all matter, and action as much an attribute of matter, as extension or solidity; and, consequently, every atom of matter is necessarily self-moving, or active from the necessity of its own nature, is asserted by Toland. Though he thought fit to reject the hypothesis of Spinosa as indefensible, yet he believed in the atheistic notion, that motion is essential to matter, and thinks it will be sufficient without troubling the Supreme Being. The reason which has always determined mankind to look out for a cause of motion extrinsical to matter, was this: though they could easily conceive it capable of being moved and divided; yet the conceiving of it to be undivided, and unmoved, was a more simple notion of matter, than the conceiving it divided and moved. This being first in order of nature, and an adequate conception of it too, they thought it necessary to inquire, how it came out of this state, and by what causes motion, from whence this diversity in matter arose, could come into the world?

Descartes, though he allowed the infinity of matter, as well as Toland, was yet sensible that even this would not alter the nature of matter, nor the idea that every person had of its inactivity, and therefore could see no way of altering its primitive idea, and reconciling it with the motion of matter, but by introducing an infinite Being, who had sufficient power to rouse matter out of that sleepy state in which its original idea had represented it.[49]

That such a circumstance exists, and what it is, a French author very clearly states. He says, The universe is composed of matter, and, as a system, is sustained by motion. Motion is not a property of matter, and without this motion the solar system could not exist. Were motion a property of matter, that undiscovered and undiscoverable thing, called perpetual motion, would establish itself. It is because motion is not a property of matter, that perpetual motion is an impossibility in the hand of every being but that of the Creator of motion. When the pretenders to atheism can produce perpetual motion, and not till then, they may expect to be credited.

The natural state of matter, as to place, is a state of rest. Motion, or change of place, is the effect of an external cause acting upon matter. As to that faculty of matter called _gravitation_, it is the influence which two or more bodies have reciprocally on each other to unite and be at rest. Every thing which has hitherto been discovered with respect to the motion of the planets in the system, relates only to the laws by which motion acts, and not to the cause of motion. Gravitation, so far from being the cause of motion to the planets that compose the solar system, would be the destruction of the solar system, were revolutionary motion to cease; for as the action of spinning upholds a top, the revolutionary motion upholds the planets in their orbits, and prevents them from gravitating and forming one mass with the sun.

“By ceaseless action all that is subsists;
Constant rotation of the unwearied wheel
That nature rides upon, maintains her health,
Her beauty, her fertility. She dreads
An instant’s pause, and lives but while she moves.
Its own revolvency upholds the world.”

In one sense of the word, philosophy knows, and atheism says, that matter is in perpetual motion. But the motion here meant refers to the state of matter, and that only on the surface of the earth. It is either decomposition, which is continually destroying the form of the bodies of matter, or recomposition, which renews that matter in the same or another form, as the decomposition of animal or vegetable substances enter into the composition of other bodies. But the motion that upholds the solar system is of an entirely different kind, and is not a property of matter. It operates also to an entirely different effect. It operates also to perpetual preservation, and to prevent any change in the state of the system.

Giving then to matter all the properties which philosophy knows it has, or all that atheism ascribes to it, and can prove, and even supposing matter to be eternal, it will not account for the system of the universe, or of the solar system, because it will not account for motion, and it is motion that preserves it. When, therefore, we discover a circumstance of such immense importance, that without it the universe could not exist, and for which neither matter, nor any, nor all, the properties of matter can account, we are by necessity forced into the rational and comfortable belief of the existence of a cause superior to matter, and that cause is GOD.

The motion of the earth, therefore, is an effect of Divine power, because there is none other equal to it; and the constant operation of the same cause is requisite to perpetuate its progress. How amazing it is that this globe, so large in circumference, should move at all! Plato attributes motion to the power of God, “How is it possible,” he argues, “for so prodigious a mass to be carried round for so long a time, by any natural cause? For which reason,” he says, “I assert God to be the cause, and that it is impossible it should be otherwise.”[50] “Every thing that is moved,” adds Aristotle, “must of necessity be moved by some other thing; and that thing must be moved, either by another, or not by another thing. If it be moved by that which is moved by another, we must of necessity come to some Prime Mover that is not moved by another. For it is impossible that what moves, and is moved by another, shall proceed _ad infinitum_.”[51] Since motion then is not a property of matter, but an effect produced by the power of a Divine agent, what a constant display we have of this efficient energy, in moving this earth, and with such a surprising, swiftness! Surely all men should fear and reverence a Being, who possesses and exercises such a power! He who created all things out of nothing, could, if he pleased, extinguish the light, and shake the solid earth into atoms!

When the ponderous wheel of nature first began to move, _time_, consisting of days, months, years, and ages, and measured by the duration and revolutions of the heavenly bodies, commenced.

_Time_ (in eternity parenthesis)
Is measur’d by successive days and months,
Seasons and years; which closely like the links
Of an extended chain progressive join:
Or as a clock, with all its hidden springs
And constant motions, wound up to the top,
Begins its course, revolving until down.

The distinction between _day_ and _night_ is a wise and gracious provision for man. In the morning, after the weary limbs have repaired their exhausted vigor by the indulgence of soft repose, we are pleased with the blessing of light; and, after a few fleeting hours engaged in our diversified pursuits of the day, we begin to court the evening shades, pleased again to enjoy that balmy retreat which alone refits us for the fatigues of the ensuing day. When a few fleeting hours are spent, the day is no longer gratifying; but its light becomes burdensome, and we wish for the shadows of the evening to be stretched over us. This sable period is scarcely gone, when we welcome the dawning day, and leave the place of our rest with gladness.

_Day_ and _night_, and their alternate changes, are adapted to suggest useful thoughts, and calculated to employ our serious meditation.

“From night to day, from day to night,
The _dawning_ and the _dying_ light
Lectures of heavenly wisdom read;
With silent eloquence they raise
Our thoughts to the Creator’s praise.
And neither sound nor language need.”

A force continually impressed by the supreme Being produces and preserves these different and useful motions, which measure out that portion of time assigned us, for the performance of his work, and the securing of our own salvation. We are directed in his word how to employ this important _talent_ lent to us; also warned to guard against a misapplication of it, and told that a day will come when we shall have to give an account of our stewardship. As _day_ is afforded for the management of those employments which could not be done in the night, how unwise would it be to postpone such concerns till the approach of darkness? So the short period of life is given us that we may “work out our own salvation.” We are favored with the light of Divine truth to illuminate our understandings; the operation of the Holy Spirit to influence our wills; and our pressing necessities should impel us to perform what God requires.

The Greeks have two words for _time_, χρονος and καιρος: the former signifies time in general; and the latter that part of it which is proper for doing a thing--the present season in which any thing to be done may be done fitly and to advantage. Accordingly Solomon says, “To every thing there is a season, and a time to every purpose under heaven.”

What the apostle says to the Christians at Ephesus is equally applicable and interesting to persons in succeeding ages of the world; giving a view of the importance of time, and directing to a right improvement of it. “See that ye walk circumspectly, not as fools, but as wise, redeeming the time, because the days are evil.”

_Walking_, in the Scripture style, is a word frequently used to denote the whole course of a man’s life and conversation, including all his thoughts, words and actions. Walking _circumspectly_, ακριβως, signifies correctly, accurately, consistently, or perfectly. In another place the same word is rendered _diligently_. Herod said to the wise men come from the east, Go to Bethlehem, and search ακριβως, _diligently_, narrowly, for the young child Jesus. But the word _circumspect_ is from the Latin _circumspicio_, and signifies to look round about, on all hands, to be every way watchful, wary, and cautious, in order to avoid danger, discern enemies before they come too nigh, and secure a man’s interest by every possible and lawful means.[52]

The necessity of this duty is suggested in the Greek text, βλεπετε ουν _see then_ or _therefore_, take care of this as a matter of the highest concern and greatest importance; it is that on which your all depends. He adduces a cogent reason for this--“Not as fools, but as wise.” As if he should say, It is your _wisdom_ to walk circumspectly, and not to walk so would be your _folly_: to walk circumspectly is the wisdom that God recommends to you, and which is adapted to make you truly wise, both in this world and in that which is to come.

The word _redeeming_, εξαγοραζομενοι, literally signifies _buying time_. The term _buying_ is proper in reference to civil contracts, but it is here applied morally. Properly speaking, time cannot be bought: it is a commodity for which all the treasures in the world would not be an equivalent. Its price is above rubies. But the term imports the great value of time, and intimates that we should be willing to suffer any privation or inconveniences, rather than lose it. _Redeeming_ properly implies the laying down a price for re-purchasing or recovering that which was ours, but which has fallen into the possession of another. A captive sometimes is redeemed out of the hand of an enemy. Now, in this sense, to redeem time already past is impossible, for when once gone it is irrecoverable. So that by _redeeming_ time, nothing else can be understood but a diligent and prudent improvement of it, which is the only way in our power to counterbalance the loss we have sustained by our former neglect. The effects of our past negligence should be counteracted by double diligence in future: we should do much work in a little time. This is to redeem that time, concerning which we have allowed worldly business, unprofitable visits, sensual indulgence, carnal recreations, and vain thoughts, to rob us, and, as it were, to take and keep us captive. To redeem time then is to be diligent in future, wisely improving it so as may make amends for our very culpable remissness. Future diligence is, as it were, the price of redemption paid down for what we had mortgaged into the hands of those things which we have suffered to deprive us of it.

The argument used to enforce the practice of this duty is, “because the days are evil.” Time, in itself, properly speaking, is neither good nor evil; but in regard to the moral state of mankind may be so called. The days here primarily intended by the apostle, denominated _evil_, were those of his own time, in which he himself and his contemporaries lived, and which abounded with trouble and danger, by reason of the opposition made by unbelieving Jews and Gentiles against Christianity. But all our days, as well as those, may be called evil, because of the prevalence of sin, Satanic delusion, and hostility of the ungodly against real religion. Many persons can adopt the language of the patriarch Jacob, “Few and evil have the days of the years of my life been.” Job gives a similar testimony, “Man that is born of a woman, is of few days, and full of evil.”

The whole argument runs thus: seeing that you cannot enjoy true quiet and substantial comfort in this terrestrial abode, and are in danger of being quickly deprived of all opportunity of getting and doing good, fail not to improve the present time to the best advantage, in reference to the future state, that you may secure for yourselves a happy and glorious eternity.

* * * * *

Footnotes - Chapter II

[23] See Dr. A. Clarke on Gen. i. 1.

[24] Barington’s Dissertations, &c, p. 82.

[25] An eminent chemist and philosopher, Dr. Priestley,
has very properly observed, that it seems plain that Moses
considered the whole terraqueous globe as being created in
a _fluid_ state, the earthly and other particles of matter
being mingled with the water. The present form of the earth
demonstrates the truth of the Mosaic account, for it is well
known, that, if a soft or elastic globular body be rapidly
whirled round on its axis, the parts at the poles will be
flattened, and the parts on the equator, midway between the
north and the south poles will be raised up. This is precisely
the shape of our earth; it has the figure of an _oblate
spheroid_, a figure pretty much resembling the shape of an
_orange_. It has been demonstrated by admeasurement, that the
earth is flatted at the poles, and raised at the equator. This
was first conjectured by Sir Isaac Newton, and afterwards
confirmed by M. Cassini, and others, who measured several
degrees of latitude at the equator and near the north pole,
and found that the difference perfectly justified Sir Isaac
Newton’s conjecture, and consequently confirmed the Mosaic
account. The result of the experiments instituted to determine
this point, proved, that the diameter of the earth at the
equator is greater by more than _twenty-three_ and _a half_
miles than it is at the poles, allowing the polar diameter to
be 1-334 part shorter than the _equatorial_, according to the
recent admeasurements of several degrees of latitude made by
Messrs. Mechain and Delambre. L’Histoire des Mathem. par M. de
la Lande, tom. iv, part v, liv. vi: and Dr. Adam Clarke, on
Gen. i. 10.

[26] Hesiod. Theog. 116.

[27] Aristoph. Aves, 694.

[28] Longin, sect. ix, Edit. Pearce.

[29] Walker’s History of the Creation, p. 8, 9.

[30] Benson on the Text.

[31] Preface to Dr. Black’s Lectures, by Robison.

[32] Carpenter’s Lectures on the Works of Creation, vol. i.
p. 87.

[33] Boerhaave’s Chem. by Shaw, vol. i. p. 299.

[34] Parkes’s Chemical Catechism, or Rudiments of
Chemistry, chap. ii.

[35] Contemplative Philosopher, vol. ii. p. 149, 150.

[36] See Dr. Burnet’s Theory, vol. ii, p. 30.

[37] Apud Stob. Eclog. Phys. p. 44.

[38] That light is a fluid which encompasses the earth,
and requires only to be agitated by some other inflamed body,
in order to render it perceptible, is an hypothesis, says a
celebrated German divine, that has been adopted by the most
eminent philosophers. “It is certain, at least, that there is
a great difference between _fire_ and _light_. The latter is
incomparably more subtile than the former. It penetrates glass,
and other transparent bodies, in a moment; whereas fire does it
very slowly. The pores of glass are consequently large enough
to give a free passage to the light, while the fire meets with
more resistance, because it is less subtile. Fire moves more
slowly than light. Let burning coals be brought into a room,
the heat diffuses itself very slowly, and the air becomes
warm by degrees; but the moment a candle is brought into an
apartment, the whole is suddenly illuminated; and wherever
the rays can reach the parts become more visible. From these
facts, and some others, it is concluded, that fire and light
are different substances; although we generally see them both
together, and find that one may produce the other. But the
consequence drawn from this is possibly false.”

[39] A new material has recently been introduced in
this country, for the purpose of lighting houses, streets,
manufactories, &c, namely, the inflammable gas of coals.
When coals are burning in a common fire-place, a flame more
or less luminous, according as it is more or less encumbered
with incombustible smoke and vapor, issues from them; and
very frequently emit some very beautiful streams of a flame
remarkably bright. All this arises from the gases which are
extricated from the coal by the heat. It was natural to imagine
that such gas might be received in proper reservoirs, and, on
being forced out of small apertures, and lighted, would serve,
as the flames of candles, to illuminate rooms or other places.
The trial was easily made, and has been attended with the
desired effect.

[40] Dr. Rees’s New Cyclopædia, Art. Light; and Dr. O.
Gregory’s Lessons, Astronomical and Philosophical p. 157.

[41] Gregory’s Economy of Nature, vol. i, p. 173.

[42] See Relig. Philos. vol. iii, pp. 869, 870, Fourth
Edition.

[43] Sturm’s Reflections, vol. iii, p. 184.

[44] Dr. Rees’s Cyclopædia, Art. Light.

[45] Parkes’s Rudiments of Chemistry, chap. xii.

[46] Sermon on 1 Pet. ii, 21.

[47] Dr. Adam Clarke on Gen. i, 31.

[48] When Zeno, the Prince of the Stoics, was endeavoring
to prove, by a sophistical argument, that there was no
motion, Diogenes, the cynic, who had come into his school to
hear him, quickly started up and walked: which was an ocular
demonstration of motion, and sufficient to refute all his
sophisms adduced to the contrary.

[49] See Gurdon’s Sixth Sermon at Boyle’s Lecture.

[50] Plato in Epinom.

[51] Aristot. Physic. lib. vii, c. 5.

[52] Dr A. Clarke on Eph. v, 15.

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