FATHER. In a certain sense perhaps so,-only with this difference. that they wished also to make a meal out of the cooks.

JULIA. That would not have been very agreeable to me.

FATHER. To our friends, too, the visit was not over pleasing. They were resting, tired of work, on their beds, when Ivan heard an unusual noise and growling, mingled with yells. He rose up and believed he had been dreaming, when he heard it anew and more plainly than before. Immediately he waked up the others. "I believe we are going to have another change of weather," said he. "Only listen to the storm."-"A fine storm!" said the old pilot; "get up and take your guns: it is the bears which are trying to break in!" They quickly sprung up, seized their loaded guns, and hurried from the cave into the hut. Gregory carefully opened the little window. The air was as cold as possible; but clear and shining, from the fiery northern lights, lay the valley covered with the dazzling snow, before him. But what a sight! what horror! Five great white bears that had become ravenous from hunger, snuffling and howling, were trying to break into the door of the hut, which, happily, was fast bolted. Ivan immediately shot at the nearest bear, and hit him so well that he staggered. The shot re-echoed through the rocky wall; some wolves which were lurking in the distance, to see if they might not also obtain their prey, raised a frightful yell and ran off. But the bears, become the more furious, stood their ground all the more firmly. They were indeed at first somewhat startled at the flash of the powder, and the report of the gun resounding through the rocks, but Soon they fell into a still greater rage, which they at once vented on their brother that had sunk under the shot, and pitched upon him furiously and tore him dreadfully. From the pain of this tearing and rending, the almost lifeless animal was roused again; and now his rage, being excited by the wound from the ball, and the mode of cure his friends had adopted with him, was raised to the highest degree. He fell furiously on the nearest of his neighbours, and in a short time they were all biting and tearing each other.

MARIA. That was fine sport to our friends.

FATHER. You think so, do you, Maria? However, great was the noise of the tearing and biting, however they might have looked on it when they were no more troubled by their enemies about the besieged hut, yet they were in continual fear lest the four might again muster and venture on a new attack, and very probably a more successful one, against their door.

Ivan and Gregory, in the meantime, were no idle spectators of the dreadful fight; they kept up a firing among them, but not a single bear fell.

Gus. Ha! I do not understand about that. They had at other times been such good marksmen!

FATHER. Probably in the confusion in which the bears all were, they could get no sure aim; it is possible also, that the bears in their fury did not regard wounds, which else would have been severe and painful.

"The fray is becoming doubtful," said the pilot; "this noise may call here more of them, and thus add to the strength of the besieging force. We must resort to another method," he added after a short reflection. "Keep at your posts till I come back." With these words he hastened to the cavern, and caught up a package of squibs.

JULIA. What did he catch up? Squibs? FATHER. Gustavus, explain the meaning of the word to your sister. It belongs in some measure to warlike preparations.

Gus. Squibs are a kind of cartridges filled with powder and other burning matters, which are used in sport, in fireworks, and seriously to frighten horses. They differ from rockets that are thrown up, as in their course they jump about in wide spaces on the ground, and therefore they are also often called frogs or snakes. At every jump they give a loud report and sprinkle fire and sparks around them.

FATHER. Very well explained. - The pilot set fire to one of these squibs and threw it among the bears, and it was fine sport to see how the thing jumped about on the hard frozen snow, like a will-of-thewisp, scattering sparks; and how with every report it made a side jump, and sometimes lighted on a bear's head, and then again on another's shaggy coat.

JULIA. How did the bears take these fire-works, let off in honour of them?

FATHER. You can easily conceive. They had never experienced such an honour. They were startled, put their

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squib struck their face, or they wallowed in the snow, when it came into closer intercourse with their thick furs.

Not to let it all go off in a joke, Gregory and Ivan shot continually at them, while the old pilot threw some more squibs, and the enemy at last drew off growling and limping, and greatly displeased, leaving one of their dead behind them. After the besieging force had withdrawn, our friends took possession of the enemy left, a monstrous white bear. With the greatest exertions, they succeeded in bringing him at first only into the hut, and bolted the door. They could not now think of trying to skin him. There was something else to be done.

(To be continued.)

ORGANS. — Of great English organbuilders, the oldest were the celebrated contemporaries and rivals, Harris and Smith, whose contention, at the time of the erection of the fine organ still standing in the Temple Church, will long be memorable among musicians. About the end of the reign of Charles II. (we forget the year), they were both engaged each to erect an organ in different parts of the church; the preferable instrument to be retained, and the other removed. They spent about twelve months in the work, and the instruments were then submitted to trial. For a long time they were played upon by the greatest musicians in England-Blow, Purcell, and others-before crowds of listeners; and the matter gave rise to a feud between the partisans of the rivals, in which all the great world of London was involved. The Honourable Roger North says, in his "Musical Memoirs," that the competition between Smith and Harris was carried on with such violence by the friends on both sides that they were just not ruined. And Dr. Burney relates that," in the night preceding the last trial of the reed stops, the friends of Harris cut the bellows of Smith's organ in such a manner, that, when the time came for trying it, it could not be played upon."

CHILDREN-FOURTH ARTICLE.)

(Continued from page 42.)

"But this application of hydrogen gas to balloons is a digression, although neither an useless, nor, we trust, an uninteresting digression. We were to have collected some hydrogen in a bag or bladder, for another purpose; we were to demonstrate what the effect would be of mixing hydrogen with oxygen in the proportion of two volumes to one, and exploding the mixture. Again we must be ingenious, must call our inventive faculties into play. Were we to write about stopcocks, union-joints, soft cement, hard cement, graduated gas-jars, and all that, the result is clear enough; our readers would never perform the experiments described would never, perhaps, read these descriptions, though, how to perform them, but contenting themselves with just glancing at the beginning of the subject and its end, they would consider that even more than enough. We must, therefore, be ingenious: stopcocks we don't mean to use, for they are rather out of the way things, and even when procured they are of no use without proper attachments. How, then, shall we manage to get a mixture of two volumes hydrogen, and one of oxygen into a moistened bladder? We will manage it thus: taking a widemouthed pint bottle, we fill it with water, and when filled, invert it in the usual manner over the shelf of the pneumatic trough. We now take a little bottle, say of two ounce capacity, and use it as a measure. This little bottle we fill with water, just as we did the large one, and invert it over the shelf of a pneumatic trough. We now fill it once, twice, with hydrogen gas, and empty it as often into the large, wide-mouthed pint bottle, taking care that no gas escapes; and, finally, we fill it once with oxygen gas, emptying the latter also into the large-mouthed pint bottle. Is it not evident, then, that at length, we have accomplished one part of our task? we have procured a mixture of two parts, by measure, of hydrogen, and one

porcelain, or glass; to the neck of the funnel let him attach, firmly, by means of some twine, the neck of the bladder, previously moistened in water to render it soft, and from which all the atmospheric air has been pressed out. Looking at the diagram, the reader will see that its neck is tied with a string a b; not tied, however, in a knot, but the string secured merely by means of one turn, in such a manner that it may readily be slipped. The funnel to which the bladder is attached is to be considered as a gas-jar, filled with water, held tightly by the left hand, whilst the mixture of oxygen and hydrogen gases is to be transferred underneath its mouth, from the large pint bottle. Need we state, at this advanced portion of our sketches, that the operation described must be performed under water?

Well, the mixed gases are now safely got into the bladder, and we can proceed with our first experiment with them, which shall consist in blowing some soapbubbles in a basin of soap solution. For this purpose the bladder must be removed from the funnel tied to the end of a tobacco-pipe, and used thus, (See Fig. 35.) Exerting pressure, bubbles will be blown,

and will collect on the surface.

"Now," said the lecturer, " having confined the mixed gases in nothing, so to speak, I will touch one of them with a taper flame. Mark now the result. They all explode violently. This part of the result is evident enough. It appeals to your ears; you hear the report. But there is another part of the result

Fig. 35.

And here our constructive ingenuity is completely at an end. The reader cannot by means of any self-constructed apparatus report the lecturer's next experiment. Fortunately, however, its nature will be so self-evident from mere description as to render the experiment perfectly easy of comprehension, if not of performance. The woodcut represents a very strong

Fig. 36.

glass vessel, something like a sodawater bottle in appearance, but open at each end; at least, capable of being opened, the upper end being supplied with a stopper, and the lower end with a stopcock, rendering the vessel itself capable of being united with a glass bell-jar, represented standing in the pneumatic trough.

Now, in the performance of the experiment about to be described, it is essential that the inside of the glass vessel be not moistened; hence it cannot be filled with gas in the ordinary manner, by means of the pneumatic trough.

The

process, therefore, had recourse to for filling it is this. The vessel itself being screwed on to the plate of an air-pump, and the latter set in action, all the atmospheric air contained in the vessel is pumped out. If, when in this empty condition it be attached to a gas-receiving jar, previously charged with the due mixture of oxygen and hydrogen gas, and the stopcock opened, it is evident that the vessel will become filled with dry mixed gas. How is the latter to be ignited? Not by the application of fire, inasmuch as that would involve removal of the stopper: then, how is it to be accomplished? Chemists now and then have recourse to very out of the way methods for gaining their results, and this is one. If the glass stopper be observed, two wires will be seen perforating it. Through these wires an electric spark can be transmitted,—a flash of lighting in miniature, which by darting through the gas inflames it. No sooner does the flash appear than the inside of the vessel, dry before, is seen to be dim with dew, which collecting sinks into a fluid drop of water,-nothing but water.

This very ingenious instrument was invented by the Honourable Mr. Cavendish, whose name it bears; still being known as Cavendish's Endiameter. It was by means of this instrument that Cavendish demonstrated the composition of water, thus rendering his name conspicuous amongst great chemists, as his eccentricities render him conspicuous to the non-scientific portion of mankind. has been described as a man without love, without hate, without hope, fear, pity, compassion, revenge, or ambition; heedless of the world's censure or applause, and totally abandoned to science.

He

The experiment just described, is a very instructive one. Let us now, for a change, present the reader with an amusing experiment. It shall present the advantage, too, of being readily performed; an advantage not presented by the latter.

Not only is hydrogen gas lighter than atmospheric air, but a mixture of two measures of hydrogen, and one of oxygen, is also lighter; hence bubbles blown with this mixture, and sent floating in the air, will ascend. If a lighted taper be brought in contact with one of these bubbles during its ascent, the bubble explodes with a very

loud noise, almost like the discharge of a gun. A word of advice to operators, who, unlearned in chemistry, perform these experiments with mixed oxygen and hydrogen gases, for the first time. Let the amount of gases mixed be not greater than absolutely sufficient for performing the experiment, and keep all sources of flame, whether of candle, spirit-lamp, or of whatever kind, as far as may be from the vessel in which the gases are contained.

Professor Faraday showed some very pretty experiments, having for their object to demonstrate the lightness of hydrogen, in addition to that with the balloon of goldbeater's skin. Having hung a glass jar, represented in

our diagram by (a), to a hook, he poured into the jar thus suspended some hydrogen gas, until the latter overflowed the jar, which the lecturer demonstrated by applying a taper-flame, when the hydrogen took fire. Finally he ladled out portions of the gas by means of a glass-ladle (6), until the large jar became quite empty. Filled the jar and ladled out the gas, do we not hear a reader exclaim (a very young reader by-the-by), how could he do that, when the jar and ladle are both pictured mouth downward, and must have been mouth downward if the jar were indeed hung from a hook? We will Fig. 37. simplify matters by minding such an inquirer that hydrogen gas, being a very light gas, pours upward not downward, and that whilst reading about pouring hydrogen gas from one vessel to another vessel, he must turn all his ordinary notions of pouring upside down; then all will be right. This was one experiment performed by the lecturer in illustration of the levity of hydrogen gas; the next was as follows:-Having previously removed one pan from the beam of a pair of scales, he hung in its stead a glass jar, as represented in our diagram by (a). Into this jar he poured (the expression will be intelligible now) some hydrogen gas, when immediately the previously existing equilibrium of the beam

re