solely for the purpose of preying upon what remains of the carcases of his prey after his lordly appetite is satisfied. A ring of jackals may often be seen surrounding a lion when engaged in feeding, patiently waiting until his wants are supplied and they can consume the remainder.

Occasionally a jackal will separate himself from his companions, and live in solitude. These hermit animals are terrible foes to the farmers, attacking the hen-roosts and sheep-folds by night, and causing great havoc amongst the assembled animals.

The fur of the jackal is of a yellowish-brown tinge, whence the scientific name, aureus-i.e., 'golden '-is derived. In size, it rather exceeds the common British fox. Like that animal, it is possessed of a powerful and unpleasant odour, which, singularly enough, gradually dies away if the creature be kept in confinement. The black-backed jackal of South Africa may be easily distinguished from the Asiatic species by the black and white markings upon the back. The size and general appearance of both animals are much the same; in habits also they are so similar that a detailed description is rendered unnecessary.

THE fiercest and most terrible animals of the dog tribe are found in the WOLVES, which inhabit almost all parts of the world, from the Arctic regions to the tropics.

There are several kinds of wolves, as well as many varieties, which by some authors are elevated to the rank of species. The best known of these is the Common Wolf (Canis lupus), which is so abundant in many parts of Europe. The colour of this animal is grey,

rather thickly sprinkled with black hairs, and tinted. in some parts of the body with a warm fawn hue; the lower parts of the body are almost white.

When found singly, which is not very often, the wolf is a comparatively insignificant enemy, his courage not being of a very high order; when banded together in packs, however, which is almost always the case, there are few animals which they cannot overcome. Even the bear himself often falls a victim to their attacks, and such powerful animals as the buffalo and the elk have little or no chance against them.

One great peculiarity in the wolf lies in its unwearying pertinacity when engaged in the pursuit of prey. Once fairly upon the trail, it follows up the victim with a long, swinging gallop, which carries it along at a wonderful pace, and is certain, sooner or later, to bring it up with the quarry, however fleet the hunted animal may be.

When the victim is once overtaken, its chance of escape is small indeed. The wolves crowd round it, attacking it with a series of fierce, snapping bites, each of which causes the teeth to meet in the flesh of its adversary. If one animal is killed, another at once takes its place, and before very long the issue of the struggle is decided.

When the victim is once slain, the wolves seem to lose all control over themselves, fighting fiercely for every morsel of the coveted flesh, and attacking each other with the most ungovernable fury. If one should be overcome, he is instantly devoured by the survivors, and it is even reported that any animal who is unfortunate enough to dabble himself with the blood of the victim is certain to share the same fate. A weak and sickly wolf, also, is sure to fall a prey to the ravenous hunger of its comrades.

The wolf is not very particular as to the nature of

his prey, animals of all kinds, even to frogs, toads, and insects, supplying him with food.

It seems strange that so bold an animal as is the wolf as a general rule, should at other times exhibit the most utter cowardice. If a wolf is caught in a trap, for instance, his courage seems at once to leave him, and he cowers down in a corner of his prison, and allows himself to be slaughtered without offering the slightest resistance.

As is the case with the lion, too, its suspicious nature sometimes offers a chance of escape to its intended victims. Travellers, when chased by wolves, have more than once escaped by trailing a piece of rope, or some other object from the carriage, and changing it for another as soon as the wolves began to lose their suspicions. The hunters also take advantage of this excessive caution, and protect their slaughtered game from the wolf as they do from the lion-viz., by planting a stick by the side of the carcase, and attaching to it a streamer of white cloth, which flutters in the wind, and deters the fierce animals from approaching.

The Black Wolf (Canis occidentalis) of America greatly resembles the last-mentioned animal, both in character and habits. In appearance also he differs only in a slight degree, and for a long time was considered to be nothing more than a permanent variety of the common species.

A smaller and more abundant animal, found in great numbers upon the vast American plains, is the Prairie Wolf (Canis latrans). These animals are always to be seen in great profusion upon the outskirts of the herds of bisons which populate the plains, hovering in the neighbourhood in the hopes of over

coming any injured or weakly member of the herd. A considerable number also usually follow the hunter, feeding upon the carcases of animals which he has slain, and from which he has taken sufficient for his own requirements.

One of the best-known of the American wolves is the Coyote, or Cajote (Canis ochropus), which is equally hated and despised by the hunters on account of its skulking and cowardly nature. This animal, which is very abundant on the prairies, has more of a fox-like aspect than the other wolves. In general habits it presents no very great difference from the previously-mentioned species.

The young of the wolves vary from three to eight or nine in number, and are brought up in a kind of nest constructed by the mother, which is lined with moss and fur pulled from her own body. When they attain the age of six or seven months, the young wolves are able to take care of themselves.

In spite of their fierce and savage nature, wolves have occasionally been tamed and brought into subjection such animals, of course, being captured when quite young, before their character was fully developed. A mixed breed has sometimes occurred, between the

strong is this scent, that any object touched by the fox retains the odour for a considerable period of time.

The fox seems to be aware of the possession of this peculiar property, although, in all probability, his nostrils are unable to perceive the odour; for when hunted he will try every means which occurs to his fertile brain to break the line of scent. For this purpose he employs a perfect variety of tricks, such as returning upon his own track for some little distance, and leaping off at right angles, in the hope of escaping before the fraud is discovered. The animal will even roll in any odorous substance he can find, in order to disguise his own peculiar scent, and mislead the hounds by causing them to imagine that they are upon the wrong track.

Many foxes become so crafty that they make their escape again and again, always contriving to elude the pack, until the hounds become completely dispirited, and consider the issue of the chase as a foregone conclusion.

There is a gravel pit in Kent which exhibits the cunning of the fox in a very singular manner.

The animal has burrowed into the ground at some

tame wolf and the domestic dog, their offspring being especially powerful and courageous.

NEXT we come to the FOXES, of which there are several species. Formerly included by zoologists in the preceding genus Canis, together with the dogs and the wolves, they were separated by later writers on account of the elongated pupil of the eye, and also from the bushy nature of the tail. The ears, too, are always triangular, and are sharply pointed.

The best known of the foxes, of course, is that found in our own country (Vulpes vulgaris), and which is so familiar to us on account of the chase, for which it is specially preserved.

The colour of this animal is a rich reddish-brown, becoming rather lighter on the lower parts of the body. At the approach of winter the fur becomes perceptibl par, asi at the same time increases greatly in thickness, just as is the case with the stoat, although not to the same degree. The tip of the tail, or brush,' always retains a more or less whitish hue.

Perhaps the most remarkable point in the nature of the fox is the singularly powerful and unpleasant odour which is exuded from the body, and which proceeds from glands situated near the tail. So

distance from the mouth of the pit, carefully concealing the entrance to the earth' among the tangled vegetation. Carrying the tunnel on, a second exit appears in the side of the pit itself, some half-way to the ground.

When hunted, the animal was evidently accustomed to enter his burrow at the upper end, pass through it, and make his escape by leaping into the quarry, while the hounds were at fault above, the idea of the second exit not being likely to strike the huntsmen, at any rate for some little time.

The same craft and cunning is employed by the fox when pillaging the hen-roosts, etc., of the neigh bourhood, his visits being paid with such caution tha detection is rendered almost impossible.

Yet, cunning as is the fox as a general rule, on some occasions his craft seems almost entirely to desert hir... The late Mr. Charles Waterton, in one of his we known essays, relates an instance of this want of sagacity.

A fox, visiting a poultry yard, had made off with eight young turkeys. Finding that his booty would more than suffice for a single meal, he buried five of his victims in a neighbouring garden, evidently intending to return on the following evening and resume his

banquet. But although the bodies of the slaughtered birds were carefully concealed, one wing of each was left projecting above the soil, thus pointing out the transaction to every passer-by. As Mr. Waterton remarks, ‘An ass, in this case, would have shown just as much talent and cunning as Reynard himself had exhibited.'

Passing to the foxes of other countries, the American fox (Vulpes fulvus) deserves a passing mention. This animal is very variable in its colouring, specimens having been found of almost every intermediate hue between black and pale yellow. A black streak almost invariably crosses the shoulders, earning for the animal the alternative title of 'cross fox.'

The Arctic fox (Vulpes lagopus) is a very well-known animal, chiefly on account of the valuable fur, which is much used in commerce. During the winter, at which time it is most in request, the coat is of a beautiful silky white, darkening to a dull greyish-brown as the season advances. The Arctic fox inhabits the northern regions of Europe, Asia, and America.

This animal appears to be almost destitute of the remarkable cunning of the others of its race, being easily trapped, and allowing a hunter to approach within easy shooting distance. In one way, however, it is sagacious enough, possessing the power of imitating the cries of the birds upon which it feeds, and so enticing them within its reach.

SOMEWHAT resembling a very small fox in general appearance, the Asse, or Caama (Vulpes caama) merits a passing mention.

This animal is found in Southern Africa, where it is remarkable for its inroads upon the nests of the ostriches, the eggs of which it destroys in great numbers. Not being able to pierce the thick shell with its tiny jaws, it rolls the egg against a stone, or other hard substance, and so contrives to obtain the contents.

Passing by the Otocyon and the Fennec, we come to the last of the dog tribe which can be mentioned in this paper, and whose position in the family is as yet very uncertain. This is the Hunting Dog (Lycaon venaticus), which has been thought to constitute a connecting link between the dog tribe and the hyænas; a final decision, however, has not as yet been arrived

at.

In fact, the characteristics of the hyenas and the dogs are so curiously intermixed in this strange animal, that it must be a matter of extreme difficulty to relegate it to its true position in the scale of creation.

The colour of the hunting dog is a reddish-brown, mottled with black-and-white patches; the nose and jaws are black, and a black streak runs along the head between the eyes. The ears are large, and the tail is long and bushy.

Like the dhole and the buansuah, the hunting dog combines in large packs for the purpose of procuring game, generally choosing the night-time for its predatory excursions. Its sense of scent is wonderfully keen, and its speed very great, and it is but seldom that the hunted animal is allowed to escape.

It will be seen that, although the cat and dog tribes both include some of the larger carnivora, the two families are, in structure as well as in habits, essentially different; and that the distinctions between the domestic cat and dog are no greater than between their more savage relatives which have never known the loss of freedom.

(To be continued.)

How I Teach Elementary Science.' FOURTH SCHEDULE SUBJECTS: MECHANICS.

BY RICHARD BALCHIN.

IT is proposed to introduce elementary science' as a 'class-subject' in the Mundella Code. It is put on a level with Geography and Grammar, and a syllabus is given in which Mechanics' occupies a very prominent place. This indicates the value set upon such kind of instruction by the Department. I think I can trace the handiwork of one of the best known and most highly esteemed of H. M. Inspectors. I am, as may be supposed, especially gratified to find my favourite subject thus treated. Of the direct encouragement given to the teaching of Mechanics by the London School Board, I can speak from pleasant personal experience. It is no wonder it should be thus highly esteemed. It is the one subject above all others that lends its aid, in the words of Gambetta, to that progress which is the development of that capital given by nature, and which is called reason.' I suppose all teachers have read Sir John Lubbock's speech at York, as reported in the Times. I felt a certain personal interest in reading it. For a short time since, one of Her Majesty's Inspectors did me the honour to bring Sir John and Lady Lubbock to Gloucester Road to hear one of my lessons on elementary science. Well, I feel that when I am engaged in this kind of teaching, I am, though in a humble sphere, a fellow worker with those men of mighty minds, who met to listen to that remarkable address from their president.

I propose in this article to give an outline of the first lesson, dealing with 'matter in the three states: solids, liquids and gases. The mechanical properties peculiar to each state.' These are the words of the syllabus. If I had had the wording of this, I should have said: 'Matter; its three states, solid, liquid and gaseous; the physical properties peculiar to each state.' In order that the teacher should know what he is talking about, and clearly conceive of a plan for best presenting the subject before juvenile minds, it is necessary that he read Tyndall's 'Heat, a mode of motion,' and especially Grove's 'Correlation of the Physical Forces,' besides the ordinary text-books on Natural Philosophy. I have found a little difficulty in deciding what shall be the basis upon which to build up my explanation of the three states of matter. Whether I shall take 'heat' as the basis, and consider the motion of atoms in the liquid as greater that that of those of the solid, and the greatest motions of all, resulting in the gaseous state; or whether I shall regard the three states as being due to different degrees of attraction of cohesion among the molecules of the respective states. It is very doubtful whether any of our boys, even in Standards V., VI. or VII., really grasp the meaning of this resolution into 'motion' of any of the physical forces. And if they cannot grasp it, it is better to leave it alone, than run the risk of forming erroneous conceptions in their minds. We must remember, too, that the very existence of atoms and molecules is theoretical. It is a theory only. It is not a well-established fact or law, like that of gravitation among the physical sciences, or of evolution among the biological ones. On the whole I think it

better to found your explanation of the phenomena under consideration upon the difference of the mutual attraction of the molecules.

Now for the lesson. The division consists of about fifty boys in Standards V. and VI. On the table is a cubic block of chalk, a basin of water, a little heap of peas, and I have an india-rubber ball in my pocket. A gas pendant is of course in the room, the gas being turned on at the meter. The black-board is up and empty. I begin the lesson.

John Jones, come here: take this block of chalk in your hands; tell me what you know about it from only feeling it. Ans. It is rough. Anything else? Ans. It easily rubs off. Anything else? Ans.-It is a square. Is he quite right, boys, in calling that a "square"? Ans.-Ño, sir; it is a cube. Yes. Now shut your eyes and tell me the shape of this (handing him the ball). Ans.-Round. Again, boys, is he right in calling that "round"? No, sir. Yes, sir. Some boy says "Yes." Why? Ans.-Because it is round, every way. It is, but the cube is also "square every way, yet you said it was wrong to call it "square." What is the proper word for this shape? Ans.—A globe or sphere. Just so. Now, Smith, you come here. Put your fingers in that basin of water and tell me its shape? Ans.-I can't feel any shape. No, you can't. It has no shape, and you cannot give it shape of itself. See, I place the chalk on the table and it remains there and keeps its shape. Now I will pour some water on the table. You see it does not remain there; it runs away. What do you think is in that pipe? Ans.-Gas. I am going to turn it on, but not light it. I want you two boys, in opposite corners of the room, to tell me when you begin to smell it. (After a few seconds)-I can smell it, sir. Yes, and so can I here. (A boy)—I can smell it. (Another boy) ---And so can I. Yes, you can all smell it. Now I have turned it off. How much gas came out, think you, while it was turned on? Ans.-This room full. Indeed? Do you know how many cubic feet that would be? Ans.-No, sir. Well, then, this room is 20 feet long, 20 feet broad, and 20 feet high; and 20 times 20 times 20 is what? Ans.-8,000. Yes; then how many cubic feet of space is there in this room? Ans.-8,000. Now do you think that 8,000 cubic feet of gas passed out of that pipe during the few seconds it was turned on? Ans.-No, sir. Why do you think not? Ans. (a boy whose father is in the gas works)-Because gas is three shillings a thousand feet, so that would be twenty-four shillings for 8,000 feet. Well, what of that? Ans. We have three or four burners in our house, going every night, and our gas only costs us 24s. for three months. (Another boy)— Please, sir, when you filled our little hydrogen-gas balloon the other day, at that burner, it took more than a minute to get quite full, and you told us that balloon held one cubic foot. Yes, that is true. boys, there was really only about one cubic foot of gas passed out while I turned it on. (A boy)-Please, sir, how could it fill this room, then? Ah! that is just what I was about to ask you. (A boy)-It spread. Spread? What spread? Ans.-The gas. know of anything else that would spread in this way? No answer? Well, suppose I bring a cubic foot of water, say that pail-full, into the room, would it spread all over it? Ans.-No, sir. How many cubic feet of water must I bring into this room to fill it? Ans.

Now,

Do you

8,000. And if I wanted to fill the room with chalk, how much? Ans.-8,000 cubic feet. Yes, and yet it seems that one cubic foot of gas will fill it. (A boy, holding up his hand.) Well? Please, sir, I can make a cubic foot of water fill this room. Can you? How? Ans. Make it hot, and turn it into steam. Yes, but then it would be vapour and not water. (A boy)-I read in one of our library books that steam and water are just the same. Yes, so they are in composition; but water in a state of steam is not called water: you can turn the vapour into water by condensing it. But you have not answered my question as to how the one cubic foot of gas can spread all over this room. Can any of you tell me? No one? Well, now listen. What would you call the smallest conceivable divisions of this gas? Ans.-Molecules. Yes, there must be a certain number of molecules in a cubic foot of it, must there not? Ans.-Yes, sir. Well, are there any more molecules in the cubic foot when it has spread all over the room, than when it passed out of the pipe? No, sir. Then what must have happened to the molecules? No answer? Look, here is a little heap of peas on the table. Suppose I wanted to make them spread all over the table, what must I do? Ans.-Put them farther apart. Just so. Then, what must have happened to the molecules of gas? Ans.-They must have gone farther apart. Yes, they separated from each other. Now, why do not the molecules of water in that basin, or the molecules of carbonate of lime in that block, separate from each other? Now think. (A boy) There must be something to keep them together. Exactly so there must be, and there is, and I will write on the board the name of that 'something'-' Attraction of cohesion.' In the case of the gas, the molecules are not only not bound together, they fly apart. Tell me some word which is the opposite of attraction.' No one can tell? You two boys come here: stand together; now push each other away. There, you see, they nearly fell down. There was certianly no attraction; what was there? Ans.— Repulsion. Just so. Now, one of you boys try and put your finger into that piece of chalk. You can't? Ans. No, sir. No, not very easily. Now put your finger into that water. Yes, that is easily done. What was it you pushed apart in the water? Ans.-The molecules of water. (A boy)-I could push apart the molecules of chalk with a nail and hammer. Yes, you could; but that requires great force. So in which of those two things is the attraction of cohesion stronger? Ans. In the chalk. Now take out your books and write: In solids, such as chalk, the attraction of cohesion is great; in liquids, such as water, the molecules move freely among themselves, for the attraction of cohesion is slight; in gases or vapours there is no attraction of cohesion at all, but repulsion, between their molecules.

End of lesson. In the next lesson I should explain that 'heat' diminishes and ultimately neutralises the attraction of cohesion.