Chapter XLV: The Cabinet of a Chef-De-Police (5)

Furthermore, beside reflection and absorption, there is one more thing that light suffers; and that we must understand before we can know properly why skies are blue, and stars are twinkling. That one thing more is called Refraction. A horse trots fairly over the stones, but slips the moment stones end, and he comes upon wood pavement. A ray of light travels straight as a dancing-master's back, so long as it is in air, or water, or glass, or any other "medium," as the books say, of a certain unvarying thinness or thickness, fineness or coarseness, or according to the school-word "density." But if a ray that has been traveling through warm and light air, suddenly plunges into air cold and heavy, it is put out of the way by such a circumstance, and in the moment of making such a change, it alters its direction. Still more, a ray of light that has been traveling in a straight line through air, is put out of its course on entering the denser medium of water; it is dislocated, refracted very much, alters its course, and then continues in a straight line on the new course, so long as the new medium continues. In the same way, a ray of light which travels through a medium that becomes denser and denser very gradually would be perpetually swerving from its straight path, and would travel on a curve. Our atmosphere is heaviest upon the surface of the earth, and becomes lighter and thinner as we rise; the ray, therefore, from a star comes to us after traveling in such a curve. But we see all objects in the direction of a perfectly straight line continued in the direction which the rays sent from them took at the moment of falling upon our sense of sight. Therefore we see all stars in a part of the heavens where they really are not; we see the sun before it really rises. Light entering a denser medium is refracted from, entering a lighter medium is refracted toward, a line drawn at right angles to its surface. Light entering a new medium at right angles--that is to say, not aslant--continues its own course unaltered.

There is but one more fact necessary to fill up the small measure of preliminary knowledge necessary for a general understanding of the phenomena produced by the mixing of light with air. Light in its perfect state is white, but the white light is a compound of other rays in due proportion, each ray being different in color and different in quality. So it takes place, because their qualities are different, that grass reflects the green ray and absorbs the rest, and therefore grass is green; while orange-peel reflects another ray, and swallows up the green and all the rest. These colors being in the light, not in the substance colored; in a dark room it is not merely a fact that we can not see red curtains and pictures; but the curtains really are not red, the paintings have no color in them, till the morning come, and artfully constructed surfaces once more in a fixed manner decompose the light. Beside the color of these rays, from which light is compounded, there are combined with them other subtle principles which act mysteriously upon matter. Upon the hard surface of a pebble there are changes that take place whenever a cloud floats before the sun. Never mind that now. The colored rays of which pure white light is compounded are usually said to be seven--Violet, Indigo, Blue, Green, Yellow, Orange, Red; and they may be technically remembered in their proper order by combining their initials into the barbarous word Vibgyor. These are called prismatic colors, because they were first separated by the passing of a ray of pure light through a prism. In that passage light is much refracted, and it happens that the contained rays all disagree with one another as to the extent to which they suffer themselves to be put out by a change of medium. Violet refracts most, and red least; the others stand between in the order in which they have just been named, the order in which you see them in the rainbow. So the rays after refraction come out in a state of dissension; all the rays--made refractory--having agreed to separate, because they are not of one mind, but of seven minds, about the degree to which they should be put out by the trouble they have gone through.

Now we have settled our preliminaries, we have got our principles; the next thing is to put them into practice. Let us first note what has been said of the absorption of light by transparent bodies. The air is one of the most transparent bodies known. On a clear day--when vapor (that is not air) does not mingle with our atmosphere--mechanical obstacles and the earth's figure form the only limits to our vision. You may see Cologne Cathedral from a mountain distant nearly sixty miles. Nevertheless, if the atmosphere had no absorbing power, only direct rays of the sun, or rays reflected from the substances about us, would be visible; the sky would be black, not blue; and sunset would abruptly pitch us into perfect night. The air, however, absorbs light, which becomes intermixed with its whole substance. Hold up your head, open your eyes widely, and stare at the noonday sun. You will soon shut your eyes and turn your head away; look at him in the evening or in the morning, and he will not blind you. Why? Remembering the earth to be a globe surrounded by an atmosphere, you will perceive that the sun's rays at noonday have to penetrate the simple thickness of the atmosphere, measured in a straight line upward from the earth; but in the evening or morning its beams fall aslant, and have to slip through a great deal of air before they reach us; suffering, therefore, a great deal of robbery; that is to say, having much light absorbed.

Now, why is the sky blue? Not only does the air absorb light; it reflects it also. The particles of air reflect, however, most especially the blue ray, while they let the red and his companions slip by. This constant reflection of the blue ray causes the whole air to appear blue; but what else does it cause? Let us consider. If air reflects or turns aside, or hustles out of its place the blue ray, suffering the rest to pass, it follows as a consequence that the more air a ray of light encounters, the more blue will it lose. The sun's rays in the morning and the evening falling aslant, as we have said, across a great breadth of our atmosphere, must lose their blue light to a terrible extent, and very likely reach us with the blue all gone, and red lord paramount. But so, in truth, the case is; and the same fact which explains the blueness of the atmosphere, explains the redness of the sunrise and the sunset. It will now easily be understood, also, why the blue color of the sky is deepest in the zenith, faintest when we look over the horizon; why the blue is at noon deeper than after mid-day; why it grows more intense as we ascend to higher elevations. From what we have already said, the reason of these things will come out with a very little thought. Again, in the example of our London fogs, &c., when in the upper portion of the dense mass the blue rays have been all refracted, there can penetrate only those other rays which make the lurid sky, with which we are familiar, or the genuine old yellow fog. Fog in moderation, the thin vapor on the open sea, and so forth, simply gives a lightness to the blue tint, or more plentiful, an absolute whiteness to the atmosphere.

Now let us see whether we are yet able to make out the philosophy of a fine autumn sunset. As the sun comes near the horizon, he and the air about him become red, because the light from that direction has been robbed of the blue rays in traversing horizontally so large a portion of the atmosphere. The sky in the zenith pales, for it has little but the absorbed or diffused light to exist upon. Presently, we see a redness in the east, quite opposite to the sun, and this redness increases till the sun sinks from our sight. In this case, the last rays of the sun that traverse the whole breadth of the atmosphere, reflected from the east, from vapors there, and more especially from clouds, come red to our eyes; no blue can be remaining in them. From the west, where the sun is setting, the rays come from the surrounding air, and from the clouds, variously colored; they lose their blue, but there remain the red, green, orange, yellow, and the purple rays; and some or all of these may make the tints that come to us, according to the state and nature of the clouds, the atmosphere, and other circumstances that may modify the process of refraction. The sun has set; it is immediately below the horizon, and its rays still dart through all our atmosphere, except that portion which is shielded from them by the intervening shadow of the earth. That shadow appears in the east, soon after sunset, in the shape of a calm blue arch, which rises gradually in the sky, immediately opposite to the part glorified by sunset colors. Over this arch the sky is red, with the rays not shut out by the round shadow of our ball. As the sun sinks, our shadow of course rises; and within it there can be only the diffused twilight, always blue. When this arch--this shadow of the earth--has risen almost to the zenith, and the sun is at some distance below the horizon, then the red color in the west becomes much more distinct and vivid; for the sun then shoots up thither its rays through a still larger quantity of intervening atmosphere; so that the redness grows as the sun sinks, until the shadow of the earth has covered all, and the stars--of which the brightest soon were visible--grow numerous upon the vault of heaven. When stars of the sixth magnitude are visible, then, astronomically speaking, twilight ends. The length of twilight will depend upon the number of rays of light that are reflected and dispersed, and that, again, will depend entirely on the atmosphere. Where there is much vapor, and the days are dull by reason of the quantity of kidnapped light, there compensation is made by the consequent increase of twilight. In the interior of Africa night follows immediately upon sunset. In summer the vapor rises to a great height, and pervades the atmosphere; the twilight then is longer than in winter, when the colder air contains less vapor, and the vapor it contains lies low.

Now, since the appearances at twilight depend on the condition of the sky, it follows that our weather-wisdom, drawn from such appearances, is based upon a philosophical foundation. When there is a blue sky, and after sunset a slight purple in the west, we have reason for expecting fine weather. After rain, detached clouds, colored red and tolerably bright, may rejoice those who anticipate a pic-nic party. If the twilight show a partiality for whitish yellow in its dress, we say that very likely there will be some rain next day; the more that whitish yellow spreads over the sky, the more the chance of water out of it. When the sun is brilliantly white, and sets in a white light, we think of storms; especially so when light high clouds that dull the whole sky become deeper near the horizon. When the color of the twilight is a grayish red, with portions of deep red passing into gray that hide the sun, then be prepared, we say, for wind and rain. The morning signs are different. When it is very red, we expect rain; a gray dawn means fine weather. The difference between a gray dawn and a gray twilight is this--in the morning, grayness depends usually upon low clouds, which melt before the rising sun; but in the evening grayness is caused by high clouds, which continue to grow denser through the night. But if in the morning there be so much vapor as to make a red dawn, it is most probable that thick clouds will be formed out of it in the course of the operations of the coming day.

Refraction of light has a good deal to do also with the twinkling of the stars; though there may go to the explanation of the phenomenon other principles which do not concern our present purpose. The air contains layers of different density, shifting over each other in currents. The fixed stars are, to our eyes, brilliant points of light; their rays broken in passing through these currents, exhibit an agitation which is not shown by the planets. The planets are not points to our sight, nor points to our telescopes; being much nearer, although really smaller, they are to our eyes of a decided, measurable size; so being in greater body, we at most could only see their edges scintillate; and this we can do sometimes through a telescope, but scarcely with the naked eye.

In rainbows, light is both refracted and reflected. You can only see a rainbow when the sun is low, your own position being between the rainbow and the sun. The rays of light refracted by the shower into their prismatic colors, are then reflected by the shower back into your eye, and so, from the principles we started with, it will be clear that while a thousand people may see under the same circumstances a rainbow of the same intensity, no two people see precisely the same object, but each man enjoys a rainbow to himself.

Of halos, and of lunar rainbows, of double suns, of the mirage, or any other extraordinary things developed by the play of light and air together, we did not intend to speak. Our discussion was confined to such an explanation of some every-day sights as may lend aid to contemplation sometimes of an autumnal evening, when

----"the soft hour
Of walking comes: for him who lonely loves
To seek the distant hills, and there converse
With Nature."

Do you not think the man impenetrably deaf who, professing to converse with Nature, can not hear the tale which Nature is forever telling?

THE WIDOW OF COLOGNE.

In the year 1641, there lived in a narrow, obscure street of Cologne a poor woman named Marie Marianni. With an old female servant for her sole companion, she inhabited a small, tumble-down, two-storied house, which had but two windows in front. Nothing could well be more miserable than the furniture of this dark dwelling. Two worm-eaten four-post bedsteads, a large deal-press, two rickety tables, three or four old wooden chairs, and a few rusty kitchen utensils, formed the whole of its domestic inventory.

Marie Marianni, despite of the wrinkles which nearly seventy years had left on her face, still preserved the trace of former beauty. There was a grace in her appearance, and a dignity in her manner, which prepossessed strangers in her favor whenever they happened to meet her; but this was rarely. Living in the strictest retirement, and avoiding as much as possible all intercourse with her neighbors, she seldom went out except for the purpose of buying provisions. Her income consisted of a small pension, which she received every six months. In the street where she lived she was known by the name of "The Old Nun," and was regarded with considerable respect.

Marie Marianni usually lived in the room on the ground-floor, where she spent her time in needlework; and her old servant Bridget occupied the upper room, which served as a kitchen, and employed herself in spinning.

Thus lived these two old women in a state of complete isolation. In winter, however, in order to avoid the expense of keeping up two fires, Marie Marianni used to call down her domestic, and cause her to place her wheel in the chimney-corner, while she herself occupied a large old easy-chair at the opposite side. They would sometimes sit thus evening after evening without exchanging a single word.

One night, however, the mistress happened to be in a more communicative temper than usual, and addressing her servant, she said: "Well, Bridget, have you heard from your son?"

"No, madame, although the Frankfort post has come in."

"You see, Bridget, it is folly to reckon on the affection of one's children; you are not the only mother who has to complain of their ingratitude."

"But, madame, my Joseph is not ungrateful: he loves me, and if he has not written now, I am certain it is only because he has nothing to say. One must not be too hard upon young people."

"Not too hard, certainly; but we have a right to their submission and respect."

"For my part, dear lady, I am satisfied with possessing, as I do, my son's affection."

"I congratulate you, Bridget," said her mistress, with a deep sigh. "Alas! I am also a mother, and I ought to be a happy one. Three sons, possessing rank, fortune, glory; yet here I am, forgotten by them, in poverty, and considered importunate if I appeal to them for help. You are happy, Bridget, in having an obedient son--mine are hard and thankless!"

"Poor, dear lady, my Joseph loves me so fondly!"

"You cut me to the heart, Bridget: you little know what I have suffered. An unhappy mother, I have also been a wretched wife. After having lived unhappily together during several years, my husband died, the victim of an assassin. And whom, think you, did they accuse of instigating his murder? Me! In the presence of my children--ay, at the instance of my eldest son--I was prosecuted for this crime!"

"But doubtless, madame, you were acquitted?"

"Yes; and had I been a poor woman, without power, rank, or influence, my innocence would have been publicly declared. But having all these advantages, it suited my enemies' purpose to deprive me of them, so they banished me, and left me in the state in which I am!"

"Dear mistress!" said the old woman.

Marie Marianni hid her face in her handkerchief, and spoke no more during the remainder of the evening.

As the servant continued silently to turn her wheel, she revolved in her mind several circumstances connected with the "Old Nun." She had often surprised her reading parchments covered with seals of red wax, which, on Bridget's entrance, her mistress always hurriedly replaced in a small iron box.

One night Marie Marianni, while suffering from an attack of fever, cried out in a tone of unutterable horror: "No: I will not see him! Take away yon red robe--that man of blood and murder!"

These things troubled the simple mind of poor Bridget, yet she dared not speak of them to her usually haughty and reserved mistress.

On the next evening, as they were sitting silently at work, a knock was heard at the door.

"Who can it be at this hour?" said Marie Marianni.

"I can not think," replied her servant; "'tis now nine o'clock."

"Another knock! Go, Bridget, and see who it is, but open the door with precaution."

The servant took their solitary lamp in her hand, went to the door. She presently returned, ushering into the room Father Francis, a priest who lived in the city. He was a man of about fifty years old, whose hollow cheeks, sharp features, and piercing eyes wore a sinister and far from hallowed expression.

"To what, father, am I indebted for this late visit?" asked the old lady.

"To important tidings," replied the priest, "which I am come to communicate."

"Leave us, Bridget," said her mistress. The servant took an old iron lamp, and went upstairs to her fireless chamber.

"What have you to tell me?" asked Marie Marianni of her visitor.

"I have had news from France."

"Good news?"

"Some which may eventually prove so."

"The stars, then, have not deceived me!"

"What, madam!" said the priest, in a reproving tone; "do you attach any credit to this lying astrology? Believe me, it is a temptation of Satan which you ought to resist. Have you not enough of real misfortune without subjecting yourself to imaginary terrors?"

"If it be a weakness, father, it is one which I share in common with many great minds. Who can doubt the influence which the celestial bodies have on things terrestrial?"

"All vanity and error, daughter. How can an enlightened mind like yours persuade itself that events happen by aught save the will of God?"

"I will not now argue the point, father; tell me rather what are the news from France?"

"The nobles' discontent at the prime minister has reached its height. Henri d'Effiat, grand-equerry of France, and the king's favorite, has joined them, and drawn into the plot the Duke de Bouillon, and Monsieur, his majesty's brother. A treaty, which is upon the point of being secretly concluded with the king of Spain, has for its object peace, on condition of the cardinal's removal."

"Thank God!"

"However, madame, let us not be too confident; continue to act with prudence, and assume the appearance of perfect resignation. Frequent the church in which I minister, place yourself near the lower corner of the right-hand aisle, and I will forewarn you of my next visit."

"I will do so, father."

Resuming his large cloak, the priest departed, Bridget being summoned by her mistress to open the door.

From that time, during several months, the old lady repaired regularly each day to the church; she often saw Father Francis, but he never spoke, or gave her the desired signal. The unaccustomed daily exercise of walking to and from church, together with the "sickness of hope deferred," began to tell unfavorably on her health; she became subject to attacks of intermitting fever, and her large, bright eyes seemed each day to grow larger and brighter. One morning, in passing down the aisle, Father Francis for a moment bent his head toward her, and whispered, "All is lost!"

With a powerful effort Marie Marianni subdued all outward signs of the terrible emotion which these words caused her, and returned to her cheerless dwelling. In the evening Father Francis came to her. When they were alone, she asked, "Father, what has happened?"

"Monsieur de Cinq-Mars is arrested."

"And the Duke de Bouillon?"

"Fled."

"The treaty with the king of Spain?"

"At the moment it was signed at Madrid, the cunning cardinal received a copy of it."

"By whom was the plot discovered?"

"By a secret agent, who had wormed himself into it."

"My enemies, then, still triumph?"

"Richelieu is more powerful, and the king more subject to him than ever."

That same night the poor old woman was seized with a burning fever. In her delirium the phantom-man in red still pursued her, and her ravings were terrible to hear. Bridget, seated at her bedside, prayed for her; and at the end of a month she began slowly to recover. Borne down, however, by years, poverty, and misfortune, Marie Marianni felt that her end was approaching. Despite Father Francis's dissuasion, she again had recourse to the astrological tablets, on which were drawn, in black and red figures, the various houses of the sun, and of the star which presided over her nativity. On this occasion their omens were unfavorable; and rejecting all spiritual consolation--miserable in the present, and hopeless for the future--Marie Marianni expired in the beginning of July, 1642.

As soon as her death was known a magistrate of Cologne came to her house, in order to make an official entry of the names of the defunct and her heirs. Bridget could not tell either, she merely knew that her late mistress was a stranger.

Father Francis arrived. "I can tell you the names of her heirs," he said. "Write--the King of France; Monsieur the Duke of Orleans; Henrietta of France, queen of England."

"And what," asked the astounded magistrate, "was the name of the deceased?"

"The High and Mighty Princess Marie de Medicis, widow of Henri IV., and mother of the reigning king!"

MY NOVEL; OR, VARIETIES IN ENGLISH LIFE.

[Continued from the October Number.]