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Popular Science Monthly/Volume 49/October 1896/Fragments of Science

Fragments of Science.

A New Classification of Elevation Areas,—Prof. Hermann Wagner, of Göttingen, one of the best-known geographers and statisticians of Germany, has recently published a new

PSM V49 D879 Wagner hypsographic curve.png

Wagner's Hypsographic Curve.

altitude classification of the earth's surface, which he divides into five regions, as follows: The culminating area of the earth's crust, occupying six per cent of the surface and lying altogether above 1,000 metres, with a mean height of 2,200 metres (or 7,200 feet) above the sea. The continental plateau, occupying all the surface from the 1,000 metre contour line of elevation to the 200 metre contour line of depth—i. e., to the margin of the shallow sea border or continental shelf; it comprises 28·3 per cent of the surface, and has a mean elevation of 250 metres (800 feet) above the sea. The continental slope, from a depth of 200 metres to 2,300 below sea level, covers nine per cent of the earth's surface, and has a mean depth of 1,300 metres (4,300 feet). The oceanic plateau, between the depths of 2,300 and 5,000 metres, occupies no less than 57·3 per cent of the surface, and has a mean depth of 4,100 metres (13,500 feet). Finally, the depressed area, deeper than 5,000 metres, is assumed to occupy three per cent of the surface, with a mean depth of 6,000 metres (say 20,000 feet). The mean level of the surface of the earth's crust is placed by these calculations at a depth of 2,300 metres, or 7,500 feet, below actual sea level. The total area of land is worked out at 28·3 per cent and that of sea at 71·7 per cent of the earth's surface; the ratio of land to water surface is thus 1: 2·54. The accompanying chart is reproduced from Nature of June 4th.

 

Silk from Wood.—According to the London Times, there is growing up in France a considerable industry, based on the manufacture of a so-called silk from wood pulp. The works are at Besançon, and utilize a process devised by M. de Chardonnet, which is as follows: The pulp, thoroughly cleansed and looking very much like thick gum, is put into cylinders, from which it is forced through pipes into the spinning department. Here the machinery is very similar to that of the ordinary spinning shed, except that one of these pipes passes to each machine. The pipes are supplied with small taps, fixed close together, and each tap has a glass tube about the size of a gas burner, at the extreme point of which is a minute aperture, and through this the pulp is forced. These glass tubes are called the silkworms, and some twelve thousand of them are in use in the factory at Besançon. The pulp appears as a minute globule. This a girl touches with her thumb, to which it adheres, and she draws out an almost invisible filament, which she passes through the guides and onto the bobbin. Then, one by one, she takes eight, ten, or twelve other such filaments, according to the thickness of the thread to be made, and passes them through the same guides and onto the same bobbin. The subsequent details are practically those of ordinary natural silk spinning. The chief difference in appearance between the natural and the artificial silk is in the greater luster of the latter. The new product is said to take dye much more readily than the natural silk, but not to be quite so strong. It is stated that a factory for the manufacture of this material is to be erected near Manchester, England, which will cost $150,000.

 

Old Madagascar War Customs.—Descriptions of curious war customs that prevailed in Madagascar are quoted by M. A. Grandidier from Mayeur, who visited that country in 1*785, or more than a hundred years ago. The hostile bands usually agreed on the day and place of the battle, and at the appointed time the opposing parties marched to the designated spot. When all was ready, some of the soldiers of one host advanced, fired their guns, and ran back to the protection of their army. While these were reloading, the soldiers on the opposite side went through the same manœuvre; and this was continued till one of the hosts got so much the worse of the fight that it retired. Both armies would then go home and return to the occupations of peace, to resume their odd hostilities at some future time. The first battle that Mayeur witnessed lasted from ten o'clock in the morning till four o'clock in the afternoon, with twelve thousand soldiers in line, without victory to either side, while there were twenty-two killed and wounded. Ten days afterward, one of the chiefs having obtained re-enforcements, the fight was resumed and hotly contested till, in the very thickest of it, a cloud of locusts suddenly darkened the sky and alighted on the neighboring rice fields. Firing was stopped at once, and all the combatants went pell-mell to picking the destructive insects, of which they were very fond as food. Women, children, and old men hurried out of the villages, where they had hidden themselves, and mingled with the soldiers; and in less than a quarter of an hour the plain was covered with more than twenty thousand people, squatting on all fours and capturing the insects. It was the custom, M. Grandidier observes, to suspend hostilities in the presence of a plague, which, as the king said to Mayeur, threatens a whole people, while war generally interests only the chief who makes it.

 

The Year's Polar Expeditions.—Dr. Frithiof Nansen, who started from Christiania, Norway, in June, 1893, in the Uttle vessel Fram, to reach the north pole if possible, has returned, after having attained latitude 86° 14′ north, within about two hundred and fifty miles of the pole, the highest point yet reached. (An excursion twelve miles farther on ski is also mentioned.) Dr. Nansen started with the expectation of meeting a current in which his vessel would be borne along with the ice to the pole and past it, basing the expectation on information which has since been found to be false. The Fram was constructed in a peculiar manner, so that when it met the heavy ice it should be lifted up and borne upon it instead of being crushed by it. In latitude 78° 50′ north, longitude 138° 37′ east, and in the latter part of September, 1893, the ship was allowed to be closed in by the ice, and was then drifted north and northwestward during the fall and winter months. A sudden increase in the depth of the water at latitude 70° to from sixteen hundred to nineteen hundred fathoms seems, according to Dr. Nansen, to upset the theories that are based upon a shallow polar basin. The sea bottom was remarkably devoid of organic matter. Under the surface of cold ice water covering the polar basin warmer and more saline water was found, probably from the Gulf Stream. No land and no open water, except narrow creeks, were seen. A few days after Christmas, 1894, the Fram was at latitude 83° 24′, the farthest north that had been reached. Dr. Nansen here left the ship, taking Lieutenant Johansen with him, to explore the sea farther north. He reached his highest point on April 7, 1895, and, finding the prospect of a further advance discouraging, started on his return journey the next day. He reached Franz-Josef Land June 7th of this year; was embarrassed to find Payer's map all wrong; and, after sailing and paddling around for several weeks in the supposed direction of Spitzbergen, met the steamer Windward. Leaving Franz-Josef Land in this vessel, August 7th, he and his companion were brought by a short and very pleasant passage to Vardöe, Norway. The Fram, which Dr. Nansen left in charge of its master. Captain Sverdrup, returned safely to Norway only a few days after Dr. Nansen's arrival. Persona best informed in arctic research affirm that the expedition has made many and valuable discoveries.

An expedition of eminent explorers, among whom are Sir W. Martin Conway and Mr. Trevor Battye, which started out to cross Spitzbergen and explore its interior, has successfully accomplished its purpose. M. Andrée, who went to the polar regions for the purpose of attempting to reach the pole by balloon, found himself constantly baffled by opposing winds, and has returned, having been obliged to give up the attempt for this year.

 

Poisonous Spider Bites.—It has always been questioned whether the bites of the spiders of the temperate zone were ever fatal. Popular belief has it that they sometimes are, but spider students generally scout the notion. A few cases have recently been cited, however, on testimony which can hardly be doubted, that point to an affirmative answer. An account is given in Dr. Biley's Insect Life of a man in excellent health who died fourteen hours after having been bitten in the neck by the species Latrodectus mactans. He instantly felt an intense pain, and picked off from the wound a spider of the species named. Four hours afterward the spot was marked by a circle of little white pimples about as large as a silver half dollar, but the wound itself was not seen; and, while there was no swelling, the neck and left arm were rigidly hard. Violent pains ensued, reaching the intestines, but the sufferer was able to go to the village for whisky and back, after which spasms set in. Sis cases of spider bites, observed by M. Corson de Savannat, were followed by serious but not mortal effect. The identity of the conditions under which the bites were received and the similarity of the observed symptoms give the cases resemblance to real laboratory experiments. All suffered great pains in the abdomen and back and tetanic contractions lasting several hours, with dyspnoic respiration and rapid, strong pulse. The patients' condition appeared desperate without its being possible to define any particular local pain. The cases were treated with injections of chlorhydrate of morphine and internal stimulants. Similar nervous troubles and contractions were marked in 1833 by M. Graells, of Barcelona, as following bites by the Latrodectus mamigniatus. In some cases a rash is mentioned as breaking out in a few hours either in the region around the bite or over the whole body, A spider whose bite is regarded as fatal is found on the seashore of New Zealand. The symptoms following the bites of these spiders are described by the New Zealand doctors as like those consequent upon the action of narcotics, while those produced by our northern spiders are rather convulsive.

 

Alaska.—Mr. W. H. Dall, in his paper on Alaska as it Was and Is (1865-1895), describes the region which includes the Aleutian chain and other islands west of Kadiak as presenting a striking contrast "to the densely wooded mountains and shining glaciers of the Sitkan region to the east and the rolling tundra, cut by myriad rivers, in the north. Approached by sea, the Aleutian Islands seem gloomy and inhospitable. Omnipresent fog wreaths hang about steep cliffs of dark volcanic rock. An angry surf vibrates to and fro amid outstanding pinnacles, where innumerable sea birds wheel and cry. The angular hills and long slopes of talus are not softened by any arborescent veil. The infrequent villages nestle behind sheltering bluffs, and are rarely visible from without the harbors. In winter all the heights are wrapped in snow, and storms of terrific violence drive commerce from the sea about them. Once pass within the harbors during summer and the repellent features of the landscape seem to vanish. The mountain sides are clothed with soft yet vivid green, and brilliant with many flowers. The perfume of the spring blossoms is often heavy on the air. The lowlands are shoulder high with herbage, and the total absence of trees gives to the landscape an individuality all its own. No more fascinating prospect do I know than a view of the harbor of Unalashka from a hill top on a sunny day, with the curiously irregular, verdant islands Bet in a sea of celestial blue, the shore lines marked by creamy surf, the ravines by brooks and waterfalls, the occasional depressions by small lakes shining in the sun. The sea abounds with fish; the offshore rocks are the resort of sea lions, and formerly of sea otters; the streams afford the trout-fisher abundant sport, and about their mouths the red salmon leap and play. In October the hillsides offer store of berries, and in all this land thei-e is not a poisonous reptile or dangerous wild animal of any sort. The inhabitants of this land are an interesting and peculiar race."

 

The Underground Houses of Techin, Tunisia.—The curious underground houses of Techin, and other places near Gabes, in Tunisia, are described by M. Albert Tissandier, in La Nature, as being easily cut out of the clay-limestone rock. A square pit, twenty or twenty-five feet deep, is generally dug first to form a central court, from the lower part of which are made the grottoes that serve as sleeping and store rooms. A gently sloping gallery rising from the level of the bottom to the level outside, and closed by a modern door, is the means of communication with the country without, or forms a path to other houses. Niches are cut in the walls of the entrance court for storage of the agricultural implements and things of minor value, and silos are provided for the grain crops and oil jars. The rooms are lighted only through the doorway from the entrance court. They are furnished with mats and carpets. A bed and a wooden pedestal for the lamp, rudely carved and whitewashed like the walls of the cavern, form the principal ornaments, and a few primitive utensils of enameled earthenware are the principal articles of furniture. The size of the house and the number of rooms, etc., vary according to the wealth and station of the proprietor.

 

A Measure for Odors.—Very interesting studies have been made by M. Eugène Mesnard of the perfumes of flowers, valuable to science and to the perfumer's art. This art is still in a rather crude state because it has never found a practicable way of measuring an odor or of determining the strength of the several odors which it may seek to combine. M. Mesnard has observed, however, that though the absolute intensity of an odor can not be measured, its comparative strength can be estimated. A perfumer who has five or six hundred kinds of fragrance in his shop can readily distinguish the differences between them, although he can not tell how strong any of them are. So it is possible to detect by the smell the existence of a large number of chemical substances, although it is impossible to guess how much, if any, of them may be present in the air. Suppose, now, the author says, we pass in a given receiver air charged with a known perfume and air which has passed over a special essence—spirits of turpentine, for example. It is possible to obtain in this way a mixture of neutral odor, or such that a very slight variation of its constituents on either side will cause the special odor of the perfume or the smell of the turpentine to prevail. We can in such case regard the two odors as equivalent, and have only to seek a means of determining the intensity of the turpentine odor to have a measure of that of the perfume. A measure for the turpentine is obtained by means of the property which it has of extinguishing the phosphorescence of phosphorus. For that purpose a bit of common starch is employed which has been dipped in a sulphide-of-carbon solution of phosphorus. The sulphide evaporates and the starch remains, a homogeneous substance impregnated with phosphorus which shines in the air. The shining may be extinguished, as M. Mesnard has shown, by the introduction of a quantity of air inversely proportioned to the strength with which it is charged with turpentine. Spirit of turpentine may thus be made a common standard for the different essences, and we may regard as the measure of the intensity t)f the perfume disengaged by a given weight of an essential oil the ratio between the weight of the turpentine which will neutralize the perfume and the weight of the same substance which under corresponding conditions will act upon phosphorescence with corresponding energy. M. Mesnard has devised an ingenious apparatus for performing practical measurements by the application of this principle.

 

Cordite.—According to the Industrial World, the manufacture of cordite is very simple. Nitroglycerin and dried gun cotton are mixed together in accurately weighed portions, the liquid nitroglycerin being poured over the gun cotton and mixed by hand until it is all taken up by the cotton, producing a dirty-white mass which looks much like sugar. This mass is then placed in kneading machines, which mix in the proper proportion of acetone. After several hours' kneading some vaseline is added and mixed in by further kneading. The mass finally becomes a stiff dough, which can be readily molded into any desired shape. The combination of nitroglycerin and gun cotton with acetone produces a compound quite different in appearance and properties from either of its components. Cordite is a heavy substance which burns only on the surface, the violence of whose explosion can hence be readily regulated by varying the relation between surface area and volume. Both nitroglycerin and gun cotton are very unstable. Cordite, on the other hand, is quite the reverse. Thus, a bonfire made around eight cases piled up against each other simply burned up the boxes and then the cordite, no explosion occurring.

 

Death of Prof. Ernst Curtius.—Dr. Ernst Curtius, Professor of History and the Fine Arts in the University of Berlin, who died July 12th, aged eighty-one years, was one of the most distinguished and most learned historians and archæologists of the century. He was born at Lübeck in 1814, of a family distinguished by love for literature and art; studied at Bonn, Göttingen, and Berlin; went with Prof. Brandeis in 1837 to Greece on an errand for the furtherance of archaeological research; afterward, with Ottfried Müller, spent four years in Greece in historical and archaeological studies, and began in 1864, but carried on with great activity after 1875, the excavations at Olympia which have been rewarded with the richest and most abundant treasures of classic art. From 1844 to 1849 he was extraordinary professor at the University of Berlin and tutor to the crown prince. In 1856 he was elected professor at Göttingen, but returned to Berlin as professor in 1868. His History of Greece is rivaled in merit only by Grote's, and is its fitting complement, supplying what Grote's lacks as Grote's supplies what it lacks, and is distinguished by the life it gives to the old legends and its appreciation of the artistic genius of the Greeks. He also published—works of equal merit in their respective fields—a book on the Acropolis of Athens (1844) and an account of the Discovery of Olympia (1882), besides many smaller works and monographs.

 

Plant Breeding.—In a recent copy of Nature M. T. Masters has an interesting article on Plant Breeding, from which the following extracts are taken: The natural processes of variation in the plant world as controlled by the art of the gardener are well typified in the garden rose of to-day—quite a different flower from those roses of our forefathers, which have, with a few exceptions, totally disappeared. It is the same with peas and potatoes and with most other plants that are grown on a large scale. The two methods made use of by gardeners for the improvement of plants are selection and cross-breeding, the latter, as far as results are concerned, only a modification of selection. The natural capacity for variation of the plant furnishes the basis on which the breeder has to work, and this capacity varies greatly in degree in different plants, so that some are much more amenable and pliant than others. The trial grounds of our great seedsmen furnish object lessons of this kind on a vast scale. The two processes are antagonistic. On the one hand, every care is taken to preserve the breed and to neutralize variation as far as possible, so that the seed may "come true"; on the other hand, when the variation does occur, the observation of the grower marks the change, and he either rejects the plant, manifesting it as a "rogue," if the change is undesirable, or takes care of it for further trial if the variation holds out promise of novelty or improvement. Where the flowers lend themselves readily to cross-fertilization by means of insects, it is essential, in order to maintain the purity of the offspring to, grow the several varieties at a very wide distance apart. Some apparently slight variations, which even to the trained botanist are hardly noticeable, may be of great value commercially; as, for instance, of two apparently almost identical varieties of wheat one may be much better able to resist mildew and diseases generally than another. Some, again, prove to be better adapted to certain soils or for some climates than others. Some are less liable to injury from predatory birds, and so on. So far we have been alluding to variations in the plant as grown from seed, but similar changes are observable in the ordinary buds, and gardeners are not slow to take advantage of these variations. The field is one of great scientific as well as commercial interest, and a thoroughly equipped biologist would probably soon distance the ordinary gardener, who works by rule of hand, in producing and perpetuating valuable variations.

 

Some African War Customs.—When war comes to the Bondei people in Africa, the Rev G. Dale, missionary, says, the first who hears it climbs up to the top of the house and beats the drum with one band, calling the people to assemble there. A drum is beaten in every village as soon as another drum is heard. Everybody goes where the first drum was sounded, and the people cry war all over the country. All the women and children go into the forest with their property, taking especial pains to carry the basket containing the money and beads. The warriors take their weapons, put their amulets on their arms and neck and face, and adjust their ostrich plumes. Each one supposes that the charms will keep him safe, and have power, even if he is struck with a bullet, to prevent its entering him. Another charm consists in scarifying the man all down his arms and breast and back, after which, it is believed, no sword will cut into his body. The great doctors have a powder which they put into water, which the warriors drink. On approaching the seat of war the warriors assemble, when every one is smeared on the face with a certain preparation and given medicine, and is licked by the fundi. Then they separate; each band goes in its special direction, and the battle takes place. If they conquer they return together singing songs signifying, "As the kishundu is a great bird and is accustomed to the mountains, so we are accustomed to war"; or, "Come and live in our land. That yonder is glowing with the fire of burned villages. We are like the Masai"; and entering the village they shout, "The land is at rest, till and eat!" If a man has been killed, they return singing, "My millet has a limit, who has eaten it?"—go to the house of the dead man, fire their guns, and take away the grass that slopes over the door—and so the wife knows that she is a widow. Then they go and tell the old folks. The man who has killed an enemy in battle performs a ceremony for seven days which includes climbing to the top of the house every morning, boasting, and naming the man he has killed. If the warriors are defeated, they come back one by one, having hidden themselves. In case of victory the women greet the warriors with great joy, and shave, for the first time since their husbands went to war.

 

Paints for Iron.—A new study of paints for iron has led Herr Spennrath to the conclusion that none of the metallic oxides entering into the composition of paints combines chemically with the oil. The drying of the paint is caused solely by the absorption of oxygen by the oil, which is facilitated in a purely mechanical way by the presence of the oxide. The relative value of the oxides is very variable. Oxide of zinc, when used in outside work, swells rapidly to twice the original volume, in consequence of the absorption of carbonic acid and the vapor of water. The red and white oxides of lead absorb sulphureted hydrogen and increase in volume. These substances are, however, good driers when they are pure. Carbon paints are very stable, but their protecting power is not great. Herr Spennrath has attempted to explain the duration of different paints by means of comparative experiments on sheets of zinc. The painted zinc was dissolved in an acid, and films of paint were obtained and subjected to various tests. AH were rapidly destroyed by the action of dilute hydrochloric or nitric acid, and of the vapors of sulphuric and acetic acids. Alkaline vapors likewise destroyed them rapidly. Pure water acts more rapidly than salt water, which goes to prove that corrosion by sea water is rather an effect of mechanical washing than of chemical action. Temperature, too, has a considerable influence on the resistance of paints. The films became brittle at a temperature of 95° C, and a perceptible contraction of the layer took place. Similar effects were produced on paints exposed for a long time to a low temperature.

 

August Kekulé.—August Kekulé, Professor of Chemistry in the University of Bonn, who died July 13th, sixty-six years old, left his mark on the science of chemistry in a distinct advance to which he gave the impulse. He was born at Darmstadt, in 1829, went to school there, and was then sent to Giessen, under the expectation that he would be educated to become an architect. But Liebig was at Giessen, and Kekulé's attention was turned to chemistry. Returning to Darmstadt, he studied chemistry under Moldeuhauer, and then entered again as a student at Giessen under Liebig and Will. He afterward studied in Paris; sojourned for a short time in Switzerland as assistant to Von Plantu, at Reichenau; was engaged at St. Bartholomew's Hospital in London; established a laboratory, where he received pupils, at Heidelberg; and became professor, successively, at Ghent and Bonn. Kekulé's services to chemistry were chiefly in the theoretical field. The twenty-fifth anniversary of his promulgation of the benzene theory was celebrated at Berlin, in 1890, and the twenty-fifth anniversary of his professorship at Bonn, in that city, two years later. He took up Frankland's theory of valency and elaborated it; laid the foundation of the study of constitutional chemistry; gave the start to the fruitful investigation of the carbon compounds; and pointed the way to thousands of important experiments and was the inspiration of hundreds of valuable discoveries.

 

Drawing Upside Down.—Observations of children drawing upside down have been collected by Mr. Rina Scott, who says, in Nature, that a great many children draw in this way, while many from the first draw the right way up. He relates that a boy of four, when asked to draw a rook on a haystack, began at the bottom of the paper with the rook's back, and gradually worked his way up to the haystack; then turned the drawing round and asked his observer to look at it—evidently realizing that it was inverted. Mr. Scott does not find the explanation of the peculiarity in any inversion of the retinal image; for, if a child who draws upside down when drawing on a horizontal table, is asked to draw on a blackboard placed vertically, he will draw everything the right way upward. He supposes that when the object seen on a vertical plane is to be represented on paper placed in a horizontal plane—in which there is already a considerable divergence from the real appearance—it is simply a matter of convenience to him at which end he begins—both being equally wrong from his point of view. So children sometimes look at picture books upside down, and small children are more ready to draw objects which they have been accustomed to see in a horizontal plane, than erect objects. Mr. Alfred W. Bennett relates that he has been able all his life to read easily a book upside down, so that it makes no difference to him which way the book is presented. This is because, as he has been told, he first learned to read, upside down, by standing in front of a brother and looking over the top of the book from which he was being taught to read. The facility curiously extends to books in foreign languages, even those in which other alphabets—as Greek and Hebrew—than the Roman are used, and to nearly the same extent to handwriting. Li a similar connection Mr. Hiram M. Stanley speaks of a strong native tendency in some children—and he might have added adults, for we have seen sign-painting in which that style was present—to reverse right and left in drawing such letters as J and L. He compares this confusion, and probably is right, with the confusion of right and left which one first feels on using a mirror for toilet purposes.

 

School Conditions and Eyesight.—Dr. Brudenell Carter has taken up the question of the effect of school conditions on the eyesight, particularly as to whether they develop and aggravate short-sightedness and the other defects of vision which have been charged to them. He examined 8,125 children in twenty-five elementary schools of London. In forty per cent of them the eyes were right. The others were subjected to further special examinations. The author reports, as the general result of his investigation, that the proportion of cases of myopia was small, and that it bore no relation whatever to the lighting of the school; the two schools in which the greatest proportions of defective visions were found being respectively the best lighted and the worst lighted of the whole number. No evidence was found of progressive myopia. Some of the worst cases were found among children who had recently joined school, and there was nothing to show that it increased with the length of time the children had been at school. The proportion of cases of astigmatism was less than the proportion discovered in Dr. Carter's private practice among patients examined for every kind of optical weakness. The vast majority of optical defects were due to hypermetropia. The most unexpected result of the investigation was the discovery that a very large proportion of the cases of defective vision were due, not to structural defects in the refractive combinations of the eye, but to imperfect practice in seeing. Comparing the vision of children at a country school with the cases in the town schools, the author found the country vision much better. It is inferred that vision is strengthened by the habit of looking at objects at a distance, which are presented far more frequently in the expanses of rural landscapes than in the street-bounded sights of the town. Dr. Carter recommends that the vision be tested and trained systematically; that it be included among the physical faculties that are tested by competition and for proficiency in which prizes are given.