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that the scholarly Bacon was the author! The plays, it is said, show a familiarity with Greek and Latin literature that had not then been translated into English, and also with the best science and philosophy of the time; but scattering references to "holy churchyards," nuns, striking clocks, and mediæval manners and customs were put into the Roman plays that we might not guess who wrote them!

GRILLPARZER ON MUSIC.

LA MARA.

Translated and Condensed for THE LITerary Digest from a Paper (9 pp.) in Vom Fels zum Meer, Leipzig, December.

FRANZ GRILLPARZER, by common consent of his countrymen, has been assigned a place among the greatest poets of Germany. In this country, he is perhaps best known as a dramatic writer, but he was no less distinguished as a musician. The music and text of his operas were both his own, and he is hence preeminently qualified to decide on the relations of the sister

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HAT most addressed itself to me in music" said Grillparzer, was the melody, the sound, which, as a nervous excitation, stimulated fantasy and imagination, if only to leave them the sport of the visions thus conjured up. And no less magically than by the melody itself, was I influenced by the natural unison of the tones in harmony with their own laws, ¿. e., not according to prescribed rules for the expression of this or that sentiment or passion. There was for me something supernatural, something infinitely holy, in music as such, in the laws of its being, and the ideal sentiments which it inspired. I prefer, therefore, instrumental music. At the same time, I am highly sensitive to the charm of the human voice in singing. On these grounds there is nothing I can more easily forgive in vocal composers than want of fidelity to their text, provided it is designed to sacrifice the text to the mere organic development and form of the musical portion. Nothing is more unendurable to me than an opera-composer who runs after the words of his text, producing thereby a fragmentary, unmelodious music wanting in organic structure."

The independent beauty of music which Grillparzer proclaimed the most liberal of the arts, was to him one of the weightiest articles of his æsthetic creed. The rigid definition and maintenance of the boundary-lines between music and the related arts was his chief concern. As early as 1819, he was occupied with the idea of writing a "counterblast" to Lessing's "Laocoön": " Rossini, or Beyond the Frontiers of Music and Poetry." "It is necessary to show," he said, in his preliminary reference to the subject, “how senseless it is to make operatic music the mere slave of poetry, and to require that the former, abjuring its characteristic function, shall limit itself to an imperfect echo, in melody, of what the poetry clearly conveys by its ideas. We have to consider wherein and to what extent the realm of music is wider, and wherein narrower; how diverse the nature of their functions are; of music, first in stimulating the nerves and senses, affecting the understanding only indirectly; of poetry, operating on the sentiments through the medium of the understanding. Music is an independent art. conforming to its own rules, conditioned by its own essence, which cannot and dare not be sacrificed even for poetry. When she selects a theme it must be organically constructed and pursued to its end, let poetry object what it will. As a fundamental principle it may be said, No opera shall be regarded from the point of view of poetry-from this point every dramatic musical composition is nonsense-but from the point of view of music. They who require from the opera a purely dramatic effect are usually they who, contrariwise, desire a musical effect from a dramatic poem, i. e., effect with blind force."

"The composer must be faithful to the situation, not to the words; the text must always be disregarded where it hampers the best effects of the music. The saying that music is a

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AN INTERNATIONAL PITCH.
C. W. GRIMM.

Condensed for THE LITERARY DIGEST from a Paper (6 pp.) in
Music, Chicago, December.

TRANGE as it may seem, the exact pitch of all tones or any single tone has never been universally settled. Every country, every city, every village, and sometimes even every orchestra, if there are several in any town, has its own pitch. Every one has it according to his own taste, because an absolute pitch has never been adopted and accepted by all.

In Europe it is established that in all cases the A shall have 435 vibrations. In the United States the A has as many vibrations as may please the manufacturer or the tuner, the latter sometimes letting the pitch drop far below the normal, because he is too lazy to raise the pitch of all the strings in the instrument. Poor instruments are often pitched high in order to sound more brilliant. Ignorant people suppose that this brilliancy is due to the high pitch. Let their instrument be lowered to the normal pitch and they will have no musical tone at all. Church organ-builders usually want a very high pitch, because they can then make the pipes a little shorter and thus save a great amount of costly material. In this way the purchaser is defrauded.

Now that England, though very reluctantly, has accepted the pitch established on the Continent of Europe, it seems a great pity that it could not be adopted in the United States and be established as an international pitch. At a meeting of the Piano Manufacturers' Association of the City of New York and its vicinity, a motion was made in the direction of adopting as a standard pitch in this country the Old World pitch, A 435.

The practical value of such a course would be that you could put together any two vocal or instrumental performers from any part of the globe, and the pitch of their notes would harmonize at once without any previous agreement. Any band or any member of it could play with any other band. Singers would know of, and perform according to, one pitch only. With a standard pitch, soprano singers could not demand to have the pitch below the normal, in order that they may pretend to sing an extra imaginary high note, nor could the bass singer demand a higher pitch, in order to sing extra low tones, existing, not in his throat, but only in his imagination,

I may speak of a commercial value of the international pitch. With string instruments this is not so important, since they can be tuned differently. With wind and wood instruments, such as organs, flutes, and brass instruments, the case is different. Nearly every brass-instrument-maker has his own pitch. Very often some member of a band would buy an instrument from a certain manufacturer, if he could use the instrument in the band in which he plays. The manufacturer's trade is therefore limited to those localities in which the pitch of his instruments is employed.

There is also an asthetic side to the question of the international pitch. A composer imagines his piece in a certain key. Suppose the pitch is different from what he imagined it. The piece, in that case, will certainly make a different impression from what he intended. If the pitch is higher than he

meant, the composition will certainly be more brilliant. Brilliancy, however, though a good quality, is not desirable in all places. If the pitch is lower than he meant, then the piece will not have all the energy the composer intended it to have. Finally an absolute pitch has an educational value. If the piano-player hears the same tone always in the same pitch, he will involuntarily learn to recognize it, if he has any musical ear at all. Unfortunately there are so many who can play only, but not hear. Music proper is what sounds, not the signs on paper or the keys of a piano. Therefore any capable teacher should teach his pupil to hear. The teacher should insist on having his pupil's pianos tuned to the proper pitch. Still further, every teacher ought to teach music-dictation, for which the piano is the most appropriate instrument. Only by means of music-dictation can the ear of the average student be systematically trained. There are a sufficient number of books containing all the necessary information.

Many people have the faculty of discerning relative pitch, which means they can say what interval they have heard, but cannot exactly give the names of the tones themselves. Others can discern the absolute pitch of any note they hear. Some possess this faculty in such a remarkable degree, that they can remember the pitch of an orchestra for several days and give it accurately after that time. These are extraordinary cases. The person who has an absolute ear, possesses in that already a relative ear. Neither Raff nor Wagner had an absolute ear. Yet for that reason surely no one will venture to say that they were not musical.

"CRUSTY CHRISTOPHER" (JOHN WILSON).
HENRY A. BEERS.

Condensed for THE LITERARY DIGEST from a Paper (2 pp.) in
Century, New York, January.

CRUSTY CHRISTOPHER was the not very suitable epithet applied by Tennyson to John Wilson (Christopher North), when the latter, in his capacity of Scotch reviewer, proceeded to pummel the English poet as was the wont of his tribe. But there was nothing crusty about Christopher; he belonged to the type of muscular Christians, and had the simple natural appetite of our Western editor for a fierce assault, whether with the pen or the more carnal weapon of the flesh.

THE

HE age of English Bards and Scotch Reviewers, when Christopher North, the veiled editor of Blackwood, delighted to pour forth his venom on a Cockney or a Whig, was essentially an age of kicks, of rough horseplay, and of coarse personalities. Libel suits and challenges rained upon magazine editors in those days.

Wilson was, perhaps, not personally responsible for all this, but he was largely contributory to it. It was a generation of fighters, and Christopher loved a fight almost as much as he loved trout-fishing, or deer-stalking, or a leaping-match, or a cocking-main, or a drinking-bout. He used to pummel celebrated bruisers in his Oxford days, when they were disrespectful to him on the King's highway; and after he became professor of moral philosophy in Edinburgh University, it was his delight to take off his coat at a rural fair, and thrash a country bully who was getting the better of a weak antagonist. There was no malice in Christopher. His hatred of Whigs was official. The Chaldee Manuscript was conceived in a spirit of noisy fun. The same spirit inspired the roistering and convivial Toryism of the "Noctes Ambrosianæ." The criticisms in Blackwood's, the roasting of Hazlitt and Moore, the sneers at Hunt's "Rimini" were simply other expressions of Wilson's love of fighting, his wild fun, and high animal spirits.

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tice to his fine qualities. In Tennyson's retort, which was unquestionably silly, he wrote:

TO CHRISTOPHER NORTH. You did late review my lays,

Crusty Christopher; You did mingle blame with praise, Rusty Christopher; When I learned from whom it came, I forgave you all the blame, Musty Christopher;

I could not forgive the praise,

Fusty Christopher.

This was very weak and the adjectives badly chosen. In certain moods Christopher may have been crusty, but rusty, musty, or fusty he could never have been. The abounding vitality, the eternal youthfulness of the man was his most apparent trait. Like Charles Kingsley, of whom he strongly reminds one, he was always a good deal of a boy.

At any rate, one always thinks of Wilson, as of Kingsley, as a forerunner of muscular Christianity-leaping twenty-three feet on a level; walking over from London to Oxford-fiftythree miles-in a night, six miles an hour heel-and-toe walking; swimming Highland locks fishing-rod in hand, tramping over the Cumberland hills with the Opium Eater, or hunting bulls on horseback with prick of spear. At Oxford, the tradition of his physical prowess lingered long, and even gave rise to legends. All his contemporaries were impressed by his personal vigor, the size of his chest, his florid complexion, the brightness of his eye, the length of his limb. De Quincy, however, denies that Christopher was a handsome man; his mouth and chin, he says, were Ciceronian, but his hair was too light, and his blue eye lacked depth-its brightness was superficial.

Wilson's literary work was profuse and diffuse, without selection and restraint. He was the most brilliant of magazinists, and Carlyle held that he had the greatest gifts among the writers of his day, but that he had produced nothing that would endure. He compared his Blackwood papers to rugged rocks overgrown with luxuriant foliage, but bound together at bottom by "an ocean of whiskey-punch." But the Ettrick Shepherd" is a dramatic creation of a high order, and the vehicle of wit, eloquence, and poetry always racy, if not always fine. Christopher was, after all, most at home in his sporting-jacket, and his outdoor papers are the best."The Moors," "The Stroll to Grassmere," and the rest. His literary criticism, though interesting as the utterance of a rich personality, is seldom wise or sure. But those who should know, have said that none ever knew the scenery of the Western Highlands like Christopher North, or described it so well.

The Apple in Legend and Fable.-There are few myths which play so conspicuous a rôle in fable and story as the apple. It shone golden in the garden of the Hesperides. Aphrodite, like Eve, held it in her hand, and the serpent and the dragon mounted guard over it. Solomon sung its praises, and in Arab story it is the fruit of healing. Odysseus yearned for it in the garden of Alkinoos, and Tantalus strove vainly to reach it in Hades; and the Edda tells us that Idursa, the goddess of Virtue, treasured apples, the gifts of the gods, of such wondrous virtue that, as age approached, she had only to taste them to renew her youth. Thus she secured perpetual youth, until Raynoröks proclaimed universal annihilation. In many a northern story, the golden bird seeks the golden apple in the King's garden, and when the tree is reached and found bare of fruit, does not Frau Bertha tell her love that it was because of a mouse that gnawed at the roots. In the mythology of the North, the apple is oft-times the tempter, and occasionally makes the nose grow so prodigiously that nothing but a pear will suffice to bring it once more into presentable shape.-Vom Fels zum Meer, Stuttgart.

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SCIENCE AND PHILOSOPHY.

RECENT SCIENCE.

ANTHROPOLOGY.

The Ribs of the Gorilla and of Man.-Describing the articular processes of the gorilla as compared with those of man, Professor Struthers said, in the British Association, that in the gorilla the chest was planted a vertebra lower than in man. The seventh presented all the characters of the normal sixth, the eighth all the characters of the seventh. In man he had seen the whole chest a vertebra too high. He had met with three cases of a rib more than usual. It was common enough in the human body; instead of the ordinary twelve, you had one more at the neck much more commonly than below. In the cases of three out of fourteen gorillas, the extra rib was in the lower part of the chest. The gorilla had one more rib than man, but he had never met with the cervical rib in the gorilla in the upper part of the chest. The tendency in the human chest was to move upward; the tendency in the gorilla's chest was to move downward. President Archibald Geikie said that in man the last rib was a diminishing element, that nothing was more striking than the excessive variations in the length of it. Every organ in the body had a marvelous power of persistency, but it seemed as if the last rib was passing out of existence. Popular Science Monthly, January.

ASTRONOMY.

Planet Notes for January, 1893.—Mercury during the first few days of January will be visible to the naked eye in the morning. One should look toward the east at 7 A.M., a little above the point where the Sun will rise.

Venus will be in the same part of the heavens, but about 15° toward the west. There will be no difficulty in seeing Venus with the naked eye during this month, but telescopic observations will be difficult, because of the low altitude of the planet.

Mars will be visible in the evening until II P.M. The best time for observing the planet is just after Sunset. The disk of Mars will be less than 8" in diameter during the greater part of the month, so that we need not expect to see much of detail on its surface. At 10 P.M. Jan. 25th, there will be a conjunction of Mars and Jupiter. Mars will pass 1° 36' to the north of Jupiter on its eastward course. A telescope with low power will at that time show both planets in the field of view at once. It will be an excellent time for comparing the light of the two planets.

Jupiter will be at a quadrature 90° east from the Sun, Jan. 5th. Or. Jan. 23d, at 6h. 43m., P.M., central time, there will be a close conjunction of Jupiter and the Moon. As seen from the centre of the Earth, Jupiter would then be only 6' north of the Moon's centre. In the southern part of the United States, Mexico, Central America, and the greater part of South America, there will be an occultation of Jupiter. In latitudes north of 38° parallax will throw the Moon to the south of Jupiter.

We presume it is unnecessary to tell many of our readers where the planets Jupiter and Mars are; but for the sake of any who may not know, we will say that they are the two bright stars which we see towards the south and about half way up to the zenith in the early evening. Both exceed in brilliancy any other stars in the evening sky. Jupiter is white, while Mars is red.

Saturn will be at a quadrature 90° west of the Sun, Jan. 2d. This planet will be in good position for observation in the morning during January. It may be easily recognized by its position in the centre of the constellation Virgo, and its bright yellow color. There will be a conjunction of Saturn with the Moon at 2h. 15m. A.M., Jan. 6th. This will produce an occultation of the planet, as seen from South America.

Uranus will be at a quadrature 90° west from the Sun, Jan. 29th, and may be observed best at from 4 to 6 A.M. This planet

is in the constellation Libra. a little west of the bright star a. It may be recognized with a telescope of moderate power by its dull green disk.-H. C. Wilson, in Astronomy and Astro Physics, December.

The Star of Bethlehem.-In a recent number of the Astronomical Journal, Mr. J. H. Stockwell combats the view, taken by Kepler nearly three hundred years ago, that the Star of Bethlehem was due to the conjunction of Saturn and Jupiter, and suggests and advocates the view that it may have been due to the conjunction of the planets Venus and Jupiter. It was the beautiful phenomena presented by these two planets when in conjunction last February that suggested an investigation into the periods at which they would have been in conjunction about the birth of Christ; and the inquiry shows that their geocentric conjunction occurred on May 8th, 6 B.C. This is about fifty days less than two years before the death of Herod. If these calculations are correct, Christ was born as early as May, 6 B.C., and between that year and 60 B.C. there occurred but one Paschal full-moon on a Friday, namely, on April 3, A.D. 33, whence it would seem that Christ was thirty-eight years old at the time of the Crucifixion.

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BIOLOGY.

Reflex Action in Turtles. Recently I had a number of mapturtles (Malaclemys geographicus Le Sueur) for student work, and observed, what is to me, a remarkable instance of reflex muscular action, both in the head and limbs. In one specimen the head had been severed from the body fully an hour, when I observed the students amusing themselves by tapping the nose of the severed head, when almost as quickly as in life the jaws would open, and when a pencil or other hard object was thrust in would close upon it with seemingly as much viciousness as in life, continuing to hold for some time, gradually relaxing, when the experiment would be tried over again. This was the case not only with the one in question, but with a half-dozen others of the same lot. Taking a specimen with the head cut off and all the viscera cleared away, leaving the legs attached to the carapace, the legs manifested sensitiveness to a marked degree. In one specimen the four legs extended from the body almost straight; a very gentle touch with the point of a pencil on the tip of a claw caused that leg to be drawn within the shell, so to speak, as quickly as in life. This was done alternately with each foot to the first again, all giving the same results. Several other specimens tested showed as much and as sudden movement, and one killed at 2 P. M., when touched at 11 A. M. the day following, withdrew its feet instantly. While these observations are common for turtles, I have not observed such marked results in other species.-M. J. Elrod, in Science, January.

ELECTRICITY.

Utilizing Niagara.—Engineers for a long time have had their attention directed to the possibilities of utilizing the enormous amount of energy wasted at the great cataract of Niagara. In 1890 the Cataract Construction Company was formed to give effect to the suggestion. Their system was to sink shafts about a mile above the falls, put turbine wheels in the bottom, and work them by means of water let in from the river. To allow the escape of the waste water from the turbines, it was proposed, to dig a tunnel around the falls which should empty into the river below. Work was begun on the tunnel in October, 1890, and is now complete. The tunnel is 6,700 feet long, 18 feet, 10 inches wide, and 21 feet high, and is lined throughout with brick. The cost has been about $900,000.

The shafts, in which the turbines are placed, are from 196 to 260 feet deep, and are being completed as rapidly as possible. The turbines and dynamos to be used in the central station, are of colossal dimensions, 5,000 horse-power being the units proposed. These are much larger than any machines of the kind ever built. The dynamos are to be placed in a horizontal

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position, and the armatures connected directly to the shafts of the turbines. What is known as three-phase" machines are to be used. On account of the great weight, and to make the friction of the bearings as small as possible, the turbines are so constructed that the water shall bear the weight of the machinery; so that the bearings, where the great weight comes, will be water-bearings. It is estimated that 100,000 horse-power can be developed at the central station. The city of Buffalo, with all her manufactories, will need only 45,000 horse-power, so that there will be over 50,000 horse-power for transmission to other points. According to recent estimates, this power can be delivered in Buffalo at $8 per horse-power per year.

On the Canadian side, the difficulties of construction are much less than on the American. A company has heen organized under a charter granted by the Canadian Parliament, 60 per cent. of the stock of which is controlled by the Cataract Construction Company.

It is estimated that there will be 300,000 horse power at the

foregoing, if resolved into gas, would occupy about ten cubic microns. This volume of gas at that temperature and pressure contains about ten billions of molecules, which for the most. part will consist each of two chemical atoms. Our speck perhaps consists of very complex organic molecules. Allowing two thousand chemical atoms for each organic molecule, the number of these very complex molecules will be about ten millions. This is an army quite large enough to admit of an immense amount of differentiation in its ranks of very active operations within and among the complex molecules, or between brigades of them, all of which are ultra-visible events. These are facts which every biologist should bear in mind when carrying out his investigations and interpreting them, and especially when he is tempted either to speak or even think, of "undifferentiated" protoplasm.-Dr. G. 7. Stoney, in London, Edinburgh, and Dublin Philosophical Magazine, December.

command of the company on the Canadian side. It is proposed J

to wait till the success of the work already begun is assured, when work will be begun on the other side of the river. In a few years, at most, we shall find that the "hoary old cataract" has really become young again, and the throbbing of its mighty heart will send energy to many distant points, where it will give, life and vigor to countless useful industries.-L. E. A., in Denison Quarterly, January.

Electricity in the Manufacture of Chemicals.-A new method has recently been discovered by which caustic soda, chlorine, and other chemical products can be made from the brine directly, by the aid of electricity. The new process effects a saving of 50 per cent. on the cost of the present methods. It is much simpler, the caustic soda being produced from the brine direct in one operation instead of two. The valuable chlorine is also saved and utilized for the production of bleaching powder. Hitherto the ocean has contributed nothing beyond a little table-salt to the world's wealth, but it has other and valuable salts in solution, and the new discovery affords promise of extended economic application. - Hardwicke's Science Gossip, December.

Electric Units.-The committee of the British Association on electrical standards has proposed the following resolutions, with a view to their adoption internationally: "(1) That the resistance of a specified column of mercury be adopted as the practical unit of resistance. (2) That 14.4521 grammes of mercury in the form of a column 106.3 centimetres long, and at oo C., shall be the specified column. (3) That standards in mercury or solid metal having the same resistance as this column, be made and deposited as standards of resistance for industrial purposes. (4) That such standards be periodically compared with each other, and also that their values be redetermined at intervals, in terms of a freshly set up column of mercury." With regard to the units of current and electromotive force, it was agreed that the number .001118 should be adopted as the number of grammes of silver deposited per second from a neutral solution of nitrate of silver by a current of one ampère, and the value 1.434 as the electromotive force in volts of a Clark cell. Prof. von Helmholtz expressed his full concurrence in these decisions.-Popular Science Monthly, January.

PHYSICS.

Ultra-visible Quantities.-The smallest organic speck that the biologist can distinguish from other specks by the highest powers of his microscope is in volume about the one-hundredth part of a cubic micron-about the 1/7000 part of the volume of one blood-corpuscle. Now, liquid or solid material, if resolved into its chemical elements, and if these be brought into the gaseous state, will, at the temperature and pressure of the atmosphere, expand about a thousand times. Hence the

PRACTICAL BACTERIOLOGY.

CARLSEN, M.D., gives in the December number of Naturen og Mennesket (Copenhagen) a very interesting and comprehensive account of how modern Bacteriology has been turned to practical use in Greece in killing field-mice, which infested the province of Thessaly and did great damage. He relates that, about a year ago, Professor Loeffler, of Greifswalde, one of Professor Koch's most prominent disciples, discovered a bacillus which produces a deadly typhus-fever in both house- and field-mice. The bacillus was, therefore, named the Mouse Typhus Bacillus (Bacillus typhi murium). Mixed with mouse-food it develops a deadly disease in eight to fourteen days, but is not dangerous for cats, rats, rabbits, pigs, small birds, pigeons, chickens, and sheep.

Dr. Carlsen next describes at length the physical and economic conditions of Thessaly, and we learn that, from time immemorial, mice have been the curse of the land, devouring the best part of every year's crop. We do not wonder, for we are told that a female mouse, from the month of March till long into the summer, bears every month six to twelve, and sometimes twenty-one, young ones. Last summer the mouse-plague was more dreadful than ever before on account of the drought. The large landowners appointed some of their class as a committee to devise means for relief. The committee called upon Pasteur, who sent them to Loeffler. Loeffler had not as yet dreamt of so large a sphere for the trial of his discovery. He accepted the invitation to come to Thessaly, and, for a consideration, try his discovery, after he had made sure that the mouse-species (Arvicola arvalis) on which he had experimented was the same as that which plagued the Thessalians. In the laboratory, the contagion was transmitted from one animal to another by pollution of their food; and by the living mice eating the dead bodies of those whom disease had killed. When he arrived in the field, however,

he found himself confronted with many difficulties; the first one was, that the Thessalian mouse was not Arvicola arvalis but Arvicola Savii. Experiments proved, however, that the Greek mouse took to the bacillus as readily as the German, and died sooner. The next difficulty was the preparation, on a large scale, of the food. In Germany, the professor had used a decoction of barley-straw, to which he added 1 per cent. peptone and 1⁄2 per cent. grape-sugar. In such a fluid milliards of bacilli would develop in the course of a night. But in all Greece there was to be found only one steam disinfectionapparatus large enough for the production of the sterilized fluid, and that apparatus was in the University hospital. After the difficulty of bursting glass bottles and condensers had been met by the use of tin, and many other difficulties had been overcome, a beginning was made in the neighborhood of Larissa. Pieces of wheat bread of about an inch in thickness. thoroughly saturated with the bacilli-fluid was placed in each mouse hole in the expectation that the mice would eat it. The Government furnished an army of soldiers as workers to teach

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the peasants how the bread was to be saturated and to show them, by eating saturated bread, that the bacillus was not dangerous to man. As soon as the peasants saw the effects upon the mice they entered upon their work with great industry; the rumor of success spread everywhere and the demands for the fluid were so numerous that no supply was sufficient. The mice were killed, and the air was soon full of birds which feed on mice. Examinations of dead mice showed that their liver and milt were overloaded with bacilli. Honors were showered upon Prof. Loeffler.

Naturen og Mennesket says editorially that the fight against the Arvicola agrestis, which does so much harm to Danish forests, is to be carried on by the use of Prof. Loeffler's typhus bacillus, and that the Agricultural College in Copenhagen furnishes the foresters with the fluid; it promises later to give full account of the battle.

SIMPLE EXPLANATION OF THE FLIGHT OF BIRDS. ERNST REICHOW.

Translated and Condensed for THE LITERARY DIGEST from a Paper (4 pp.) in Der Stein der Weisen, Vienna, December.

AERIAL NAVIGATION is now unquestionably one of the leading problems of the age, and in spite of the practical difficulties still unsurmounted,, there is a growing confidence that they will all yield to man's inventive genius.

The author confines himself in the present paper to an elucidation of the mechanics of bird-flight, but clearly points to the conclusion that aërial navigation depends for its satisfactory solution on the application of the same principles. LIGHT involves wing-surfaces-pressure-surfaces-which must be both large and light. For example, a body weighing seventy kilograms will require approximately ten square metres of wing-surface.

FLIGHT

The wing-surfaces of birds are supporting-surfaces, liftingsurfaces, and, relatively, gliding-surfaces. These wing-surfaces are approximately about one two-hundredths of the weight of the bird.

The down-stroke of the wing is rapid and resisting, the up-stroke slower. There results a quick lift (Fig. 2), and as the upper surface is very smooth and gently arched, the up-stroke meets with less resistance. From the effect of the down-stroke results the possibility of rising-the lifting power. The stroke of the wing itself is not so simple a matter as it appears.

(a) In the form of a bent bow, Fig. 1, shows this bow with the action suspended, Fig. 2, during flight.

(6) As the wing-surface from the beginning to the end of the stroke makes a shovel-shaped or scooping movement (Figs. 3 and 4), scooping the air from above forward, and striking it

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downward and backward, by which the wing-surfaces describe a partial twist on the long axis-identical with part of a screwstroke-there results a combination of two operations, a raising, and a forward pushing-movement, which constitute together one operation of flight.

1. The so-called horizontal flight is not really rectilinear, but undulating. Supposing the bird rises from the ground, he holds his body obliquely, and rises in an oblique course by rapid strokes of the wing. On reaching a desired height he brings his body to the horizontal direction by means of his steeringappliances, and pursues his horizontal course, accelerated by the influence of gravitation. The bird is continuously subject to this force, which it overcomes with every stroke of the wing, and the quicker the operation, the more rapidly the bird shoots forward, as is evident from the principle of the stroke defined under (b).

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The bird must then renew his stroke or he will glide gradually downward. If a bird floats a considerable distance without beating his wings or descending, it is in consequence of a resisting current.

3. Circling in horizontal curves is not undertaken by the bird until by rapid strokes he has equipped himself with force of propulsion; if he will then circle, he inclines his body towards the inside of the circle to be described (Fig. 5) like a horse in the manège, and the centrifugal force at once comes into operation. If the circle is contracted, the floating can be maintained longer, for the bird is ever nearing the centre of

FIGURE 5.

the circle by a spiral sweep. Ordinarily, however, the circle is widened, rendering it necessary to resort oftener to the beating of the wings.

But in every kind of sailing the bird imparts to his wings, however rigidly they may be stretched, a more or less obliquely

For an intelligent horizontal flight, the steering-appliances upward direction (Fig. 5), consequently in the direction of the

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