their experiments on the electric discharge in various gases and in vacua being taken as evidence. They believe that at a height of about thirty-seven miles, the display of the aurora is at its highest brilliancy; is much less brilliant at eighty-one miles; and scarcely visible or even possible at one hundred and twenty-four miles. The color varies markedly with the tenuity of the air. At a pressure of sixty-two millimètres, the magnificent carmine tint prevails which is so characteristic of auroral phe nomena; but as the pressure is reduced the tint changes to salmon color, and from that pales off to milky whiteness. "The roseate and violet tints," says the experimentalists, "are always in the vicinity of the positive source of the electric current. The positive luminosity fades away gradually, and frequently becomes almost invisible at some distance from its source." GAMES AS TEACHERS.-Mr. Latry, 12 Boulevard St. Martin, Paris, has invented historical cards and geographical dominos, with a view to interest children and young people in their own education, and to provide a means of instructive recreation. For example: the departments of France are represented by different series of picture-cards; the name of a department is called; the players immediately produce the prefectures and under-prefectures of that department or any other particulars. In the same manner, on specifying a reign, the cards are played which illustrate the incidents of that reign; and the best player is the one who places the incidents in true chronological order. In geography, the cards aid in defining the ancient provinces as well as the modern departments; they illustrate, moreover, the leading historic facts and the characteristic manufactures of the towns and cities. The dominos, inscribed with dates instead of the usual numerical spots, convert the study of history into a pastime; or, applied to geography, may represent the principal river-valleys of France or any other country. In practice, it is found that a child soon learns the names of the water-courses in a river basin, of the towns through which they flow, is able to identify their position and form a mental picture of the whole. The name chosen for this new game is " Magister," because any one of the players by clever moves may become master. So far as can be judged from these particulars, it is an amusing as well as instructive recreation. When made gas compressed to a liquid state. fast to the sunken object, the communication between the cistern and the balloon is opened; inflation takes place; the sunken vessel or whatever else it may be, is lifted, and can be towed away at pleasure. In the experiment at Kiel, an anchor-stone weighing fifteen tons was thus raised from a depth of thirty-two feet. The lifting power of a balloon ten feet in diam eter is said to be more than one hundred and thirteen tons. THE ELECTRIC LIGHT IN MINES.-The electric light has been brought into use with great advantage in the slate quarries of Angers, France, for instead of digging away the upper strata to get at the good merchantable slatean operation that required months of unremunerative labor-the quarrymen get out the slate by mining. It is in the deep underground workings that the electric light is employed, the result being that with the increased light the laborers do not require their hand-lamps, that the work is better done than before, that a greater quantity of slates is produced, and the liability to accident is diminished. ORGANISMS IN ICE.-Mr. M. A. Verder has been making some microscopical investigations with regard to the purity of ice taken from canals and ponds, specimens being selected from the interior of blocks which appear clear and transparent to the unassisted eye. On melting the ice and examining the water with a power of 900 diameters, bits of vegetable tissues and confervoid growths were recognizable at once, and upon allowing the water to settle and become warm at the ordinary temperature of a room occupied for living purposes, the sediment deposited was found to contain, after some hours, monads whose movements are easily discernible with a magnifying power of from 200 to 400 diameters. As the result of these investigations he is fully convinced that freezing does not free water from filth due to the presence of sewage or decaying vegetable matter. MEN WITH TAILS.-Professor Virchow has recalled attention to this subject. One of the longest tails on record is that reported by Greve in 1878. This occurred in the case of a new-born infant, was 7.5 centimètres in length, and moved about when pricked with a needle. It was removed by an operation. Virchow has recently dissected this tail, and found it not to contain any bone, cartilage, or muscle ; nevertheless, it was a good substitute for a tail. Michel has pointed out that in the human embryo a rudimentary tail is distinctly made: and the discovery of men with tails seems to lend support to Lord Monboddo's theory, that all mankind originally wore them.—British Medical Journal. VARIETIES. APPARENT SIZE OF THE MOON.-M. J. Plateau proposes a method of estimating approximately the apparent distances at which the moon seems to different people to be in the sky. This means consists in looking at the moon steadily until the retina is sufficiently fatigued to produce an “accidental" image or ghost. The observer must then turn his gaze to a blank wall, on which he will see the accidental image projected as a tinted patch of the same shape as the moon. He is then to retreat from, or advance to, the wall until this image appears to him to be of the same size as the moon did itself. The distance measured off between the observer and the wall will be the same as that at which he unconsciously takes the moon to be. One of the sons of the author having made this experiment, found the distance to be in his case about fifty mètres. This seems a small distance, but it was the result of a single experiment under circumstances which were not very favorable. M. Plateau concludes the brief memoir on the subject, presented by him to the Belgian Académie, by cautioning all persons who may be interested in the subject to take care, in repeating the experiment, lest the great brilliance of the luminary should damage their sight. SPIDER-KILLING WASPS.-The following is an interesting extract from a lady's letter, dated Pietermaritzburg: "In a corner of my bedroom window a bit of architecture has been going on which has much interested us all. A pair of slender wasps, with golden bodies and purple wings, came and built, bit by bit, most industriously and fast, seven tunnels of clay; the male insect worked, he fetched the moist pellets of clay from a distant puddle outside the garden. These he worked with mouth and paws into shape most beautifully. When the first tunnel was complete, the female went in and laid her eggs at the bottom. Then together they flew away, and came back with a spider, half killed (that is, stung to a deadened state, but so that it would keep and not putrify), and poor spider was tucked into the tunnel. The pair worked on hunting for spiders all day and popping them in, and night surprised them too soon; so the male fetched a pellet of clay and made a perfect door, closing up the hole from all intruders, and they disappeared. morning, quite early, I opened the shutter, without which they could not get at their work, and very soon they arrived. They cut and tugged at the still damp door till it came away clear and left the open arch, and several more unfortunate spiders were added to the larder of the future grub, laid in embryo at the end of the tunnel. Then it was closed with fresh clay, and made doubly secure by an extra thick In the ness of daubing. And immediately, without waiting to rest, another tunnel was built side by side with the first. For days, I think quite a fortnight, we watched their steady work, until seven of these wonderful tombs-or should I say habitations? were filled and closed. After the insects had quite finished and gone altogether, leaving the whole daubed together and cemented into one large lump of various shades of clay, I cut it out of the window, and have got it in a basket covered with net, so that we may see the exit of the young creatures that are to eat through all those spiders and break their way into the world some day. I opened one tunnel lengthwise that we might see and count the spiders-there were fifteen in it! Fat-bodied little garden spiders of various sorts; one was too big to push in, so they had cut its legs off at the roots! We waited just a little too long before digging an opening into that wasp's mud castle. What we found was this A long transparent brown case, and within it a wasp perfectly formed, but colorless. Not a trace of the fifteen spiders! And these must have been eaten by the little grub which came out of the egg-probably the egg was laid in the fat body of a spider; and when the spiders were all eaten we can only suppose the grub went through a change and came into the wasp, but how that beautiful case was formed over it I cannot imagine. You could see the creature inside perfectly as if it were made of glass, and the whole thing exactly fitted the tunnel of clay. After a few more days, another tunnel was opened, not by us, but by the perfected wasp itself. A round hole at the end was cut as if with a sharp instrument, and out walked the pretty creature, slowly and sleepily. Then it walked up on the top of the clay mound and spread its wings in the sun, and looked out at the world, quite ready to take its place at once on the business of life. We uncovered the net from the basket and let it fly ; and next season I shall look out for another such erection, and open the tunnel earlier, so as to see the grub when half through its larder of cold meat. We saw another and much larger sort of wasp the other day running along with a very large fat caterpillar which it had deadened; it held it by the head in its mandibles, and the body trailed along under the whole length of the wasp and out behind, and the caterpillar was so fat that the wasp had to stride along on tiptoe to carry it at all. At last it stopped-left the body a moment, and began like a terrier to scratch at a hole; the loose earth fell away at once, and was evidently only banked up to hide the hole from intruders. The wasp ran in and disappeared; presently out he came again, backward, with some earth which had fallen in; and he did this several times, throwing out all the earth which had tumbled in. Then he ran and inspected the body of the caterpillar, ran all round it gleefully, and dragged it nearer to his hole. Then we laughed to see the clever fellow, sailor-like, turn himself round and pop down the companion, tail first; and then peeping out, he reached out his head and arms, and seizing the caterpillar, pulled it down after him, into what seemed a long gallery, leading a great distance. No doubt an egg was laid in the body of the caterpillar for the future grub's sustenance."-Hardwicke's Science Gossip. THE RELIGION OF ANCIENT ROME.-If the religion of the Greeks was more fully and richly developed than that of the Romans on the side of speculation, the Romans, on the other hand, cultivated the law with more zeal and earnestness. In fact, they almost resemble some Oriental nations, Aryan and Semitic, in the scrupulous minuteness into which they bent the most trifling transactions of life under the yoke of religious duties. It is true they were free from the minute regulations concerning eating which in the East were an important and characteristic part of religious law. They did not know the difference between clean and unclean animals, nor were the Eastern laws of fasting and manifold washings imposed upon them. All asceticism was unknown to them. But, nevertheless, the observances prescribed by their religion were so numerous and imperative that no transaction of any importance was free from them. Prayers, offerings, vows, religious ceremonies, minutely regulated for every emergency, were of vital importance. The least oversight, the least neglect might draw down the anger of the gods. Even ignorance was no excuse, for the divine interpreters of the will of the gods were at hand to expound the law and to prescribe for every occasion the proper rite of worship. The religion of Rome was a full and carefully elaborated legal system. It laid down minutely the duties of man, and the fines to be paid on every transaction. It regulated the intercourse between gods and men, and showed how the good-will and co-operation of the gods could be obtained by a certain and infallible process. It was, like the civil law, full of fictions and casuistry. It imposed no obligations but those which could be accurately circumscribed by the number and quality of sacrifices and services. It suggested no such thing as love or trust or hope. notion of virtue in our sense of the word was unknown. Cicero defines piety as "justice toward the gods," and he adds the significant words, "What piety is due to those from whom we have received no benefit?" It is clear that the human conscience played a very insubordinate part in such a religion. Morality had nothing to do with it. Every iniquitous action The was allowed by the state religion, provided a man could show that he was formerly in the right. Even the gods might be cheated lawfully if a man was quick and sharp enough to avail himself of some formality in the divine law, or could interpret a doubtful injunction in his favor. An omen sent by the gods might be accepted or rejected, or interpreted in the most convenient and profitable way. A false and lying announcement by an augur had the efficacy of a true one, provided it was duly made in the prescribed form. Unlucky signs were not allowed to prevent any undertaking upon which a Roman magistrate was bent. It was only necessary to repeat the process of divination until the desired favorable signs appeared. If the entrails of the first animal were found faulty, a second was slaughtered, and a third, and so forth, until heart and liver were found to be such as foretold success. If no favorable birds would appear on the first inspection of the sky, the augur had only to continue his observations long enough, until he saw what he wished to see.-From • Early Rome," by Professor Ihne. BETWEEN JOY AND SORROW. BETWEEN joy and sorrow, I lay for a space; And blossoms what bough? "But all there is quiet; On the waif-cumber'd coasts, PHILIP BOURKE Marston. LOVER'S SILENCE. WHEN she whose love is even my air of life |