Q. How do you distinguish that light which is alike refrangible?

A. It is known as primary, simple, homogeneal light.

Q. By what terms do you know that light, the rays of which are not alike refrangible?

A. Those rays are known as compound, heterogeneal, and dissimilar. The colours produced by homogenous rays are termed primary or simple; those of heterogenous are known as secondary or mixed colours.

Q. How are those bodies known through which light quickly passes?

A. They are said to be transparent, as air, glass, water, &c.

Q. By what term are those bodies known through which light does not so pass?

A. They are known as opaque bodies, as stone, wood, &c. Q. What causes one body to be transparent, and another to be opaque?

A. By Sir Isaac Newton transparency was supposed to arise from the particles and their intervals or pores being too small to cause reflexion at their common surfaces; so that all light which enters transparent bodies passes through them, without any portion of it being turned from its path by reflexion. Opacity he supposed to arise from an opposite cause; namely, when the parts of bodies are of such a size as to be capable of reflecting the light which falls upon them, in which case the light is "stopped or stifled" by the multitude of reflections.*

Q. Are the same terms still adopted, to give the cause of transparency and opacity?

A. Transparency is now supposed to be connected with the arrangement and density of bodies: when particles are uniformly arranged and of equal density, the light which falls on them is equally attracted in all directions; it is therefore in the same state as if not attracted at all, and passes freely through these bodies. Many, if not all, bodies attract and admit light; but the particles of these bodies being either unequal in density, or not uniform in their

arrangement, the light is so differently attracted and directed, by such a number of surfaces, of different densities, as not to find a passage through them, and they are termed opaque. The different states of carbon may illustrate this: when crystallized, we have in the diamond one of the most transparent and dazzling substances in nature; when in the form of charcoal, it is black and opaque.

Q. You say that light is supposed to proceed especially from the sun may I venture to ask, what is that glorious body? how does light proceed from it? and what are those spots thereon of which I have frequently heard?

A. As an humble inquirer like yourself, let me take you to Dr. Herschell for replies to your queries. By this celebrated man, the sun is supposed to be a solid opaque body, which turns on its own axis, the primary planet of our system; a habitable world, which has mountains and valleys like our earth, higher and deeper in some proportion to the magnitude of the two bodies; and that the inhabitants thereof are furnished with organs adapted to their residence.

It is also supposed that the sun has an atmosphere capable of being decomposed; that the emission of light is connected with the actual decomposition of this atmosphere; and that this luminous atmosphere, and not the sun itself, is the glorious object we behold. This atmosphere is supposed to consist of various fluids, more or less transparent; and as the clouds belonging to our earth are probably decompositions of certain elastic fluids, so we may suppose that in the vast atmosphere of the sun similar decompositions may take place, but with this difference, the decompositions of the elastic fluids of the sun are of a phosphoric nature, and attended by lucid appearances, as they give out light.

This atmosphere is sometimes so transparent, as to allow parts of the body of the sun to be seen through it; and what we term spots are, in fact, either the high mountains of the sun, projecting beyond this shining atmosphere, or openings therein, by which these mountains are seen: these black spots are known as macula. The sun has also some peculiarly bright and shining parts, which are termed

tures of these luminous fluids, or their condensation on some peculiar parts of the surface of the body.

In this way Dr. Herschell supposes light to be connected with the sun; accounts for the spots that are seen thereon ; and supposes that the rays are not hot in themselves, but produce this sensation by their action on other bodies.

The sun is the great and glorious image (if it be lawful to speak of a created image) of God, "dwelling in light;" of Him who is the απαυγασμα from the αυγασμα, the proceeding splendour from the inherent splendour, (Dr. Clarke, Heb. i. 3,)" the Light of the world," and the source of uncreated heat."

"Hail, holy light; offspring of heaven first born!
Of the eternal co-eternal beam.

May I express thee unblamed? since God is light,
And never but in unapproached light
Dwelt from eternity, dwelt then in thee,
Bright effluence of bright essence increate.
Or hear'st thou, rather, pure ethereal stream,
Whose fountain who can tell?

Celestial light,

Shine inward, and the mind through all her powers
Irradiate there plant eyes, all mist from thence
Purge and disperse; that I may see and tell
Of things invisible to mortal sight."

THE SIN AND PUNISHMENT OF GEHAZI.

WHAT the true principle and source of Gehazi's guilt was, will best appear from his punishment; which being dictated by the Spirit of God was, beyond all doubt, rightly

directed.

When Naaman was healed of his leprosy by obeying the directions of the Prophet Elisha, he returned in gratitude to acknowledge the obligation; and earnestly entreated the Prophet to accept from him some valuable proofs and tokens of his gratitude. The Prophet having absolutely refused them, his servant thought that was an осса

means to be lost: and therefore he resolved at once to disgrace his master, and in him the religion of his God; to violate the truth, and to defraud Naaman, rather than leave his own vicious appetites unindulged. Doubtless he deemed the Syrian garments proper ornaments to adorn his person; and when that was done, the other conveniencies of life must be adjusted, and suited to them: this consideration made oliveyards and vineyards but necessary conveniencies, suited to the other circumstances of his dignity.

The spirit of the Prophet attended him, through the inmost recesses and windings of his heart, (which plainly demonstrates it to be the Spirit of God,) saw clearly into his most secret purposes, and immediately suggested a punishment most admirably accommodated to all the circumstances of his guilt: he inflicted a distemper upon him, which made all those vanities useless at once. Syrian ornaments would but ill become a leprous carcase; and would, in effect, but make his deformities more conspicuous: and, indulgence of appetite would but more inflame his incurable disease; which must go down to his posterity, together with his ill-acquired inheritance.

Ah! how many unhappy Gehazis are there in the world, who trample under foot every duty they owe to God and man, and derive to themselves worse than leprosies, in consequence of their vanities of dress, and unruly indulgence of appetite; and convey the taint (but mostly without the inheritance) to their posterity!

The love of pomp, and of the glare of dress, is a false and fantastic appetite. And all such appetites are gratified with difficulty; and not only so, but draw after them many other congenial and vexatious vanities, leading to enormities of every kind.

Gehazi's guilt was a taint, that had infected his soul; and it was chastised by an infectious disease, that bore an amazing and a dreadful analogy to it.

Sin is to the soul, what the worst diseases are to the body; ulcers, and loathsome corruptions, of every kind. And the disease now inflicted upon Gehazi was at once a most

shocking picture and punishment. How finely and how dreadfully instructive is this history to us! and how strictly and religiously should we be upon our guard, lest the inward defilements of our sins should descend, like those outward pollutions of Gehazi, to our latest posterity; and derive not only mortal diseases, but immortal miseries upon them!

That the people of this nation are overrun with strong appetites and unruly vanities of various kinds, as Gehazi was, is a truth equally lamentable and notorious. This is the true source of those pests that infect your cities and infest your highways. This is the true cause why so many of your sons grow up, not as healthful, but as poisonous plants; that your daughters grow up, not as the polished corners of your temples, but as the polluted corners of your cities. This is the true source of that great decay, that leading into captivity, and that complaining in your streets, far beyond the corruption and calamity of all former ages.

This is the true reason why so many of one sex openly act as if the laws of the Gospel were totally reversed to them; forgetting, or entirely neglecting, to adorn themselves with modest apparel, with shamefacedness, and sobriety; but, on the contrary, glaring in the eyes of the world, with broidered hair, with gold, and pearls, and costly array, and an equal contempt of modesty and sobriety.—Delany.

ORIGIN AND MATERIALS OF BOOKS.

PRIOR to the invention of paper, a variety of substances were employed for inscriptions, manuscripts, and books. An enumeration of some of these will tend to throw light on several passages of Scripture, which must appear very singular to persons who are not acquainted with the form and materials of ancient books.

1. STONE and BRICKS.—It is generally admitted that stone was one of the first substances on which figures and afterwards letters were engraven. Of this there is abundant evidence in the fact of the decalogue, or ten command