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8. CHEMISTRY.

the room.

PRACTICAL SCIENCE.

large bottle to receive the first portion of the gas that escapes from the flask, because it is mixed with the air, and consequently useless for experiment, and is usually al

lowed to escape in the room; but if reCHLORINE.

ceived into this large bottle it will prevent 1. To make the gas. I intend making you interrupting me by coughing, and the some chlorine gas for you to-day, and try bottle may be afterwards placed in the garing a few experiments with it; but before den, and the gas allowed to escape there. doing so, I must beg that you will not

I observe that some of you are holding come too near the apparatus, and that you your handkerchiefs to your noses; and will not remove any of the stoppers from this reminds me that I had forgotten to the bottles of collected gas, when my at- mention that it is advisable to sprinkle a tention is directed to some other part of strong solution of ammonia about the table,

and also to have a towel saturated with it, You observe that I have a stand, with a near at hand. I have not neglected this

moveable slide and precaution on the present occasion; as
ring to hold a retort some of you have reminded me with tears
or flask, and that in your eyes.
the Florence flask,

There are two methods of making this gas; placed in the ring

and as I wish you to know how everything of the stand, is is done, we will prepare some gas by each. fitted with a cork,

You see that I have put some black having a bent glass powder into the mortar, and also an equal tube, securely fixed portion of common salt. The black pow. in it, and" long der is the black oxide of manganese ; and enough to pass to when the two are well mixed by rubbing the bottom of the them together in the mortar, we will take bottle, which is two ounces of the mixture and place it in also placed in the the retort ready for use. [Does so, after

same manner as I the salt and black oxide of manganese are shall require to use it afterwards, with a mixed). The bottle you see in my right cover of greased cardboard, and a spirit- hand contains sulphuric acid, or, as it is lamp underneath the flask.' You see that commonly called, oil of vitriol; and when I have also several square pieces of card this is mixed in a thick earthen jug, with board and glass, all well greased, and some an equal quantity of water, we shall have greased stoppers lying near to these differ- advanced another step in our preparation ent sized bottles upon the table ; and that of chlorine. You must be careful in mixon my left-hand side, there are some pieces of ing sulphuric acid with water; because if printed calico, a sprig of parsley, and various the combination takes place in a thick glass other things, all of which we shall require. or earthenware jug, it will probably break The reason that you were requested not the vessel, in consequence of the sudden to approach too near the apparatus is, be- heat produced by mixing the acid with water. cause chlorine gas is exceedingly irritating I would therefore advise you to use a wooden to the lungs, and when breathed excites bowl and a stick, to mix them well. coughing, spitting of blood, and violent in- Now that the acid is properly diluted, fiammation of the air passages. Even when I will pour some into the flask, and by largely diluted with the air it is very irri- shaking it occasionally the powder will tating, and therefore I have provided a mix more readily with the fluid, and pre

sently we shall see that the lower part of * Discovered by Scheele, in 1774. Chemical

the flask contains a thin paste. It is very symbol, C-atomic weight =36 ---specific gravity necessary to moisten the powder well; for =2.5, or about 2 times heavier than common air. if this precaution be not observed, the bottom The name of chlorine, which was given to this gas of the flask would break when the flame of by Sir H. Davy. is derived from the Greek word chloros (xlwoos), which signifies yellowish the spirit-lamp came in contact with it.

Some gas is passing out of the fiask,

green

although I have not yet applied any heat, we have upon the table serves for this and therefore the cork fitted with the method, and the manner of proceeding is bent glass tube must be put in, and the gas precisely the same. Some chemists add collected at once. (Places the tube and cork two drops of oil of turpentine, to prevent in the flask, and the flask in the ring of the the materials frothing up. retort-stand, as in the figure, page 129]. You Chlorine gas in a pure state may also observe that I do not apply the flame of be obtained by acting on one part of powthe spirit-lamp to the bottom of the flask dered bichromate of potash in a small at once, but that the flame is moved back- retort, with six parts of strong hydrowards and forwards underneath it. When chloric acid. The retort is gently heated this has been done for a few minutes, you at first, and then the heat withdrawn, as it should remove the flame of the spirit-lamp, is only required to commence the process. and wipe the surface of the flask, so as to We will now try a few experiments with get rid of the superfluous moisture, the the gas already collected in the bottles. product of condensation.

[Experiment 1.) You remember I menThe ordinary method of collecting gasestioned that this gas was highly irritating in bottles for experimenting is by means to the air-passages, and therefore is not of a pneumatic trough, as it is generally calculated to sustain animal life. Here is called; but as we shall consider this upon a mouse which is racing about at full another occasion, I shall only allude to it gallop in his cage, and you will see that here. You appear astonished that the when it is suspended in this jar, it will plan was not adopted in the present in die instantly. [Drops the mouse into the stance, particularly as you have no doubt jar, and it dies immediately.] Now seen many lecturers collect it over water although this gas is so irritating that it like other gases; but although it is done, has already made some of you cough, and yet the practice is bad, because, as we shall killed the mouse, yet it has been found presently see, water absorbs chlorine gas, that when largely diluted with atmospheric and therefore until saturated with it, you are air, it acts beneficially upon persons expending the gas without any benefit, un- affected with certain diseases of the lungs, less, indeed, you wish to make chlorine water and moreover, that the labourers employed at the same time. By using strong brine, the in the bleaching manufactories, and those gas may be collected without losing much persons residing near to them, are seldom of it by absorption. The best plan is, to let attacked with consumption. the end of the bent tube pass to the bottom [Experiment 2.] I stated that the reaof the receiving-bottles,—which should be son this gas was not collected over water, loosely covered with a piece of card, as in was because the water absorbed chlorine. ile apparatus on the table,

see if such be really the case. being much heavier than the air in the Here is some distilled water, which I am bottle, displaces it, and when the bottle going to pour into the bottle of chlorine is full of the greenish coloured gas, we place gas before me. [Adds the water.] You see a greased stopper firmly in the bottle, or that about a third of the bottle is occupied cover the mouth of it with a piece of by the water, and the remainder by the greased card-board, and supply its place gas. I will shake the bottle well, and with another receiving bottle.

you will then observe the yellowish-green We have now collected several bottles colour disappear from the upper part of of the gas, and are therefore prepared to the bottle. [Performs the experiment, perform some experiments ; but before and the water absorbs the chlorine.] We doing so, I will describe the other method may now safely assert that one part of of obtaining chlorine.

water will absorb two parts of chlorine Instead of putting a mixture of salt and gas. The solution we have made is called black oxide (per-oxide) of manganese into chlorine water, which is used as a bleaching the retort or flask, and adding diluted sul- agent, and for destroying offensive effluvia, phuric acid, we place one part of the and arresting putrefaction. In order that black oxide of manganese in the flask, and you may remember these properties of the add two parts of strong hydrochloric acid, aqueous solution of the gas, we will try or spirit of salt. The small apparatus / some experiments with it.

This gas,

Let us

an

[Experiment 3.) Here is a piece of you saw, is simply this. The oily vapour putrid meat, and although the effluvia from arising from the wick unites with the it now is most offensive, yet soon after its chlorine and becomes inflamed, because immersion in the chlorine water, the the gas has a remakable affinity (or noisome odour will be destroyed. [Per- attachment we may say) for hydrogen, forms the experiment.] If fresh meat be which is contained in the inflammable suspended over chlorine water or sub- matter of the taper. The following experimitted to the fumes of the gas, putrefac- ment will illustrate the truth of these tion will not take place, and the chlorine remarks. water thrown down offensive drain [Experiment 7.] Here is a piece of speedily removes the disagreeable effluvia paper, moistened with oil of turpentine, arising from it.

and when it is plunged into this bottle of [Experiment 4.] Here is a tumbler of chlorine gas, it will burn with a brilliant

a solution of indigo, and we flame. [Fixes the paper on the end of a will pour in a little of the wire, similar to that used for the taper, chlorine water, and stir it and plunges it into the bottle, when it inwith this glass rod, and you stantly inflames, and a dense smoke (carwill then see the bleaching bon) is deposited at the same time). qualities of the gas. [Does [Experiment 8.] Let us try a few more

so, and the colour of the experiments, to prove that chloride is a solution is destroyed.]

supporter of combustion. Here is a lump [Experiment 5.] Let us see if the gas of charcoal, which was only made two will bleach as well as the aqueous solution hours ago, (in fact the experiment could of it. Here are two bottles. I shall sus- not succeed well unless the charcoal was pend a sprig of damp parsley in one, and freshly made), and when it is reduced to a this piece of printed calico in the other. fine powder, and dried, I will pour some [Does so.] You observe that the parsley of it into this bottle of the gas, and the has already become rather yellow, and is effect will be beautiful. [Pounds and dries rapidly assuming a white appearance, and the charcoal, and performs the experiment, the piece of printed calico is also white. when a vivid stream of fire is observed). If you took a small bouquet of flowers [Experiment 9.] If we affix a small and dipped them into water, and then, sheet of gold-leaf to a wire, and plunge it having shaken off the superfluous moisture, into a bottle of the chlorine, we shall see immersed them in a jar of the gas, you it burn with a brilliant green flame. If would have a white bouquet of all kinds of we used silver leaf instead, the flame would flowers and leaves.

be white; tin, when heated in a defla(Experiment 6.] As chlorine gas grating spoon, or a small iron cup, at the

unites with some substances with end of a wire, burns with a blueish white
evolution of heat and light, it is flame when immersed in this gas; bismuth,
termed a supporter of combustion, heated in a platinum spoon, burns with a
and yet it extinguishes a lighted blue flame ; and iron, heated in a platinum
taper imniersed in a jar of it. Here spoon, burns with a vivid red light.
is a disc of greased card-board, and Other metals may be burned in chlo.
we will pass this wire through it, and rine; but they should never be tried except
affix a lighted taper to one end. If by those who are skilled in the mysteries
you will hand me over that bottle of chemistry, because the fumes from some
of the gas, I will plunge the taper of them are dangerous if inhaled.
into it. [Does so.) You saw that could show you many of them, but let me
when the taper was first placed in particularly caution you against following
the gas that the flame was extin- the experiments given in any works, where

guished, but that it was afterwards sufficient caution is not enjoined, because re-kindled, and continued to burn with you may either lose your life or health. a small red flame, and emit a quantity Be assured, that whatever I tell you will of smoke, and that this fame was ex- be always sufficient guarantee that there tinguished when the taper was removed is no danger, unless accompanied by the from the bottle. Now the reason of what necessary warning, - in which case, of

FLOWERS.

VI. THE STAINED LILIES.

conversant

course, the pupil, and not the teacher, is to blame.

STORIES FOR THE YOUNG. Chlorine unites with many metals, forming chlorides or chlorurets ; but we must not stay now to consider them, further than to illustrate the truth of the observation by a simple experiment.

A family of white Lilies once dwelt [Experiment 10.] Here is a solution of beside a placid lake in the still woods. lunar caustic, or nitrate of silver, and For many seasons they had lived in conwhen I add a little of the chlorine water to tented happiness ; and generation after it, you will see that a curdy kind of deposit | generation had blossomed into perfect takes place, this is the chloride of silver. loveliness, and flung their rich fragrance [Performs the experiment].

on the forest winds. They heard no Let me once more caution you never to praises save the hum of the insects, and perform any experiments with chlorine and the song of the birds. No rude touch the following articles, until you are more ever sullied their purity; and when their

with PRACTICAL SCIENCE, lives were spent, they calmly scattered otherwise the consequences may be serious. their leaves upon the bosom of the still

Arsenic, Mercury, Phosphorus, and lake that had alone reflected their Antimony, should never be experimented beauty, with by the inexperienced, and not even by The Lilies were very happy in this sylvan those well versed in chemical knowledge, solitude, and they dearly loved the bright unless with EXTREME CAUTION.

clear waters that sent nourishment to their

roots, and in whose transparent depths POLITENESS AND TRUTH.—Many per- they saw constantly mirrored sweet images sons plead a love of truth as an apoiogy for of themselves. No ripple disturbed the rough manners, as if truth was never gentle perfect calm of its surface, save when a and kind, but always harsh, morose, and passing breeze ruffled its waters slightly, forbidding. Surely good-manners and a and then the sweet, pure faces of the flowers, good conscience are no more inconsistent as they smiled fondly upon it, seemed soon with each other than beauty and innocence, to restore its wonted calm. which are strikingly akin, and always look The sunbeams peeped down among the the better for companionship. Roughness thick foliage of the forest trees, and wove and honesty are indeed sometimes found a network of gold upon the breast of the together in the same person, but he is a lake, and the little birds soared gaily poor judge of human nature who takes above it, and dipped their wings in its ill-manners to be a guarantee of probity of waters as they passed. At night the quiet character ; or suspects a stranger to be a stars came out, and looked steadily down rascal, because he has the manners of a into the clear depths,-for they love the gentleman. Some persons object to po- Lilies because they are the stars of earth; liteness, that its language is unmeaning and, beyond all, the blue sky was reflected and false. But this is easily answered. A in the still lake like another heaven. lie is not locked up in a phrase, but must But the constant Lilies only saw all these exist, if at all, in the mind of the speaker. beautiful things as the lake showed them; In the ordinary compliments of civilized and they were content to know that when life, there is no intention to deceive, and the sun was veiled, and the birds gone to consequently no falsehood. Polite lan rest,--when the stars were set, and the guage is pleasant to the ear, and soothing sky obscured by clouds,-still the faithful to the heart, while rough words are just waters reflected their images steadily and the reverse ; and if not the product of ill- unbroken; nothing could shake the earnest temper, are very apt to produce it. The affection of the lake: and for the Lilies, plainest of truths, let it be remembered, were not their roots embedded beneath its can be conveyed in civil speech, while the waves ? inost malignant of lies may find utterance, As the family of Lilies increased and and often do, in the language of the fish spread along the shores of the lake, one inarket.

group that dwelt near an opening in the

wood, where the stream entered that sup- “Delightful, indeed,” cried the other, plied its waters, began to look longingly pleased with the impression she had made, out upon the world beyond. They bent " and you can do nothing better than forward over the bank, and noticed not the accompany me thither in the early spring; calm reflection of the still lake while they you will have a gay life, I can assure you, eagerly gazed between the trees, where and enjoy more in one season than if you afar off they could see the little stream were to mope here in the woods for ever.” come tumbling over the stones with a So the Lilies listened to the words of the mirthful rush, and only subsiding into foolish Columbine, and consented to take quiet just before it joined the placid lake her advice ; and without saying a word to of the Lilies.

the rest of their family, who they knew There was something in the rapid waters would oppose them, they carefully gathered that fascinated the flowers; and when a their seed in the seed vessel, and, through wild Columbine, that had lately sprung up the agency of Columbine, arranged with at their side, flung her blossoms on the Zephyr to transport them away together in still lake, and awakened no murmur of the early spring. admiration in return, she spoke sneeringly The inconstant Zephyr was enraptured to the Lilies.

with his mission, for the tall forest trees “Such a quiet, prosy sheet of water as screened the Lilies from his insidious this lake is I never saw before,” she said ; advances, and the stately flowers had "why, you have dwelt here time out of scarcely ever bent their heads in acknowmind, and I don't suppose it has ever told ledgment of his salutations; he now antiyou how lovely you are. I wonder you do cipated much pleasure in moving the not tire of such a monotonous life.” transplanted flower, and cheerfully fulfilled

“But the lake loves and nourishes us, his task." if it does not flatter us,” replied the Lilies; Accordingly, one lovely morning, the " and let what will pass over its surface, Lilies awoke in their new home, and were it reflects always our images the same.” for a little while completely dazzled by

“That is all very well if it suit you," the flood of sunshine that burst upon them. returned the Columbine, who resented the When they became accustomed to the indifference with which the lake had re- bright light, so different from the softened ceived her advances ; " but for my part I shadows of their own green wood, they should soon die with weariness, shut up for glanced eagerly around. ever in this still place, and seeing always The merry stream went rushing noisily the same things. I shall certainly beg over the stones at their feet, and broke into Zephyr to carry me back to the spot a thousand fantastic eddies as it sped along; whence I came,- I cannot live here.” there were myriads of flowers upon the

"Where is your home ?asked the banks eagerly bending over to catch a Lilies, eagerly.

glance at the laughing stream, and the “Just at the side of the stream beyond,” | hum of insects completely bewildered them. answered the giddy flowers; we grow on There was no shade, no quiet anywhere, a bank where the water flows most rapidly, and before the Lilies had even time to see and new eddies are continually forming as themselves reflected in the water, a new it rushes on, in which we see ourselves eddy dimpled its surface and destroyed reflected in ever-varying forms; then the the perfect image. Soon the stream flung stream is always shouting and singing as drops of spray toward them, shouting that he goes,

and dashes the spray playfully at they were crystal diamonds to form a corous, saying the drops are fairy mirrors in net for the lovely flowers ; and every which to view our beauty, and the breezes ripple that reflected them in new forms, whisper to us as they pass ; while as for the flattering stream declared only made insects, they surround us, constantly hum- them lovelier. ming our praises."

Soon Zephyr came with murmuring "How delightful such a life must be,” sighs, and whispered of their fexile grace sighed the Lilies, who were silly enough to and exquisite beauty, singing praises in be charmed with the chatter of their gay tones borrowed from the musical reeds and neighbour.

the inurinuring leaves. The bold sun

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