Popular Science Monthly/Volume 11/May 1877/Popular Miscellany
Cotton-Culture in Egypt.—While the Khedive is taxing to the utmost the resources of his dominions in his desire to subjugate his southern neighbors, he must regard as little less than providential the reputed discovery of a new and extraordinarily-productive species of cotton-plant, the general cultivation of which in the cotton-fields of Egypt will, it is said, more than double the present annual product. According to a correspondent of the London Times, in the autumn of 1873, a Copt living in the upper part of the Delta, at a place called Berket-el-Sab, a station of the Cairo Railway, in the province of Menuf, noticed a plant in a cotton-field wholly different from the rest. He collected the pods, separated the seed, and planted it in secret in an. isolated plot of ground. For three years he has carried on the cultivation, and now there are said to be from 800 to 1,000 pounds in the country, and the seed is sold in the public market. This seed is sold at a price twenty-five or thirty times higher than the common kind.
Comparing the product of this plant with that of the old, the Times correspondent remarks:
"An ardeb (270 pounds) of ordinary cotton-seed sows on an average eight feddans (acres), and produces four cantars (100 pounds) of cotton in seed—that is to say, the cotton with the seed inside it as it comes out of the cotton-pod. Taking this yield as the average, every ardeb planted produces 32 cantars of ginned cotton, and about 24 ardebs of seed. An ardeb of seed of the new species sows, like the other, eight feddans; but its yield is more than treble, and has even been stated at fivefold. But my most trustworthy informant only gives ten cantars per feddan, which I may add is the amount taken by one of the leading firms as the basis of their calculations as to the effect of the new plant. They add that it is difficult to say exactly what would be the ordinary yield, as all returns hitherto are the result of exceptional culture on a small scale. On this calculation of ten cantars, each ardeb of seed would produce 80 cantars of cotton in seed—that is to say, over double the amount produced by ordinary seed. At present prices each ardeb would return about £240 in seed and cotton together, instead of £96 as it does now. The new cotton, I am assured on the best authority, is of good appearance, commercially speaking, and quite equal in quality to the ordinary Egyptian cotton. The plant grows in a different manner from the ordinary cotton-plant. It grows to about the height of ten feet, has a straight, vertical stem, without branches, with very few leaves, and is thickly studded with pods. Seventy are said to have been gathered from the first plant discovered. The ordinary cotton is found on a shrub some four to five feet high, with spreading branches. Nearly a yard must be left for air, light, and growing-room between each shrub, whereas the new plant, from the absence of branches, requires only half the space."
Testimonials to Mr. Darwin.—On the occasion of his sixty-ninth birthday, Mr. Darwin was the recipient of two highly-gratifying testimonials of esteem from scientific men in Germany and in the Netherlands. From Germany came an album containing the photographs of 154 scientific men; it was inscribed, "Dam Reformator der Naturgeschichte" (To the Reformer of Natural History). The offering of the Dutch savants also consisted of an album, with photographs of 217 of his admirers in the Netherlands. Accompanying the latter testimonial was a letter in which were set forth in pretty full detail the labors of Dutch naturalists before Darwin's time and since in propagating views akin to those known as "Darwinian." The first name mentioned in the letter is that of Dr. J. E. Doornik, who in 1816 went out to Java, and spent the remainder of his life in India. In his published works he held that the various modifications in which life was revealed in consecutive times originated from one another. Doornik had no influence on the thought of his time, however, and his theories were forgotten. In 1849 was published a Dutch translation of the "Vestiges of the Natural History of Creation." This work was coldly received by the representatives of natural science in the Netherlands, but found favor with the general public, and reached a third edition. Of the few Dutch scientific men who early recognized the importance of the theory of development two are named—F. C. Donders and P. Harting. The former in 1848 expressed the opinion that in the gradual change of form consequent upon change of circumstances may lie the cause of differences which we are wont to designate as species; and the latter in 1856 expressed similar views.
While visiting Utrecht in 1858, Sir Charles Lyell called the attention of the professors of the university to a paper by Wallace, in the Journal of the Linnæan Society, and announced as forthcoming a work by Darwin ("The Origin of Species") which could not fail to make some noise. Harting soon after declared himself a partisan of the development hypothesis, and in this he was followed by another professor in the same university (Utrecht), Miguel, Professor of Botany. In the mean time "The Origin of Species" had been translated into Dutch by F. C. Winkler. The Darwinian views were now enthusiastically adopted in the Netherlands, especially by the younger scientific men, under the lead of Emil Selenka, then Professor of Zoölogy at Leyden. Gröningen and Amsterdam were not tardy in following the lead of Utrecht and Leyden; in short, the Darwinian theory of development was very generally accepted throughout the Netherlands, and Dutch translations were published of "The Descent of Man" and "The Expression of the Emotions in Man and Animals," both by Dr. Hartogh Heys van Zouteveen. In his reply to this letter, Mr. Darwin expresses his "obligation for the very interesting history contained in it of the progress of opinion in the Netherlands with respect to evolution, the whole of which is quite new to me."
Ignorant Enterprise.—The black-slate beds of Pennsylvania have again and again lured sanguine coal-hunters to loss of time, labor, and money. In that State it is the black slate that plays the "will-o'-the-wisp" to the eager searcher after hidden wealth; elsewhere it is iron pyrites being mistaken for gold, or quartz for diamonds; and where natural deposits of wealth are out of the question, men dig into the ground in search of treasure supposed to have been buried by famous buccaneers or noted misers. Prof. Persifer Frazer lately told, at a meeting of the Academy of Natural Sciences, Philadelphia, the story of one of these searchers for mineral wealth. A farmer of Franklin County, Pennsylvania, had a dream, in which he became aware of the existence of a "treasure" in a certain field. On repairing to the spot he began to dig, and "at the first stroke of the spade," as he says, "black dirt was turned up, and at a short distance below the surface coal was found equal," in the opinion of persons supposed to be experts, "to the best Lykens Valley coal." To work the vein, a tunnel 330 feet long was cut at considerable cost. The "coal" was sent to Prof. Frazer for analysis; it was pronounced to be black slate, with a small percentage of carbon, and that chiefly graphite. It is one of the principal objects of a geological survey to save people from making mistakes like this of the Franklin County farmer.
Production of Near-Sightedness in Schools.—The effects of school-life, in producing near-sightedness in the pupils, have for some time been made the subject of systematic study by Dr. C. R. Agnew, of New York. In a recent address before the Medico-Legal Society, he stated the results of an investigation made in various schools of Cincinnati, New York, and Brooklyn. The number of students examined was 1,479, of whom 630 were in Cincinnati, 549 in New York, and 300 in Brooklyn. Of the 630 Cincinnati pupils, 209 were from the district-schools, and of these 832 per cent, had natural, or emmetropic eyes, while 10 per cent, were near-sighted. In the intermediate schools, 210 scholars were examined, and of these 80 per cent, were natural, and 14 per cent, near-sighted. In the normal high-schools, the eyes of 210 students were examined, and of these 78 per cent, were emmetropic, and 16 per cent, nearsighted. All this goes to show that nearsightedness is a progressive disease in the schools. The results for the other two cities teach the same lesson.
The 549 students mentioned above as examined in New York belonged to the New York College. Here, in the introductory classes, 572 per cent, were found emmetropic, and 29 per cent, near-sighted. In the freshman class 422 per cent, had natural eyes, and 40 per cent, were near-sighted. In the sophomore class no very material difference from what was observed in the preceding classes; but in the junior class 37 per cent, had natural eyes, and 56 per cent, were near-sighted. In the senior class 50 per cent, had normal eyes, and 37 per cent, were near-sighted. The Brooklyn students examined belonged to the Polytechnic Institute of that city. Here, in the academic department, 56 per cent, were emmetropic, and 10 per cent, near-sighted. In the collegiate department (a higher grade), 53 per cent, were emmetropic, and 282 per cent, were near-sighted.
Astronomical Observations on the Rocky Mountains.—It is stated by Prof Henry Draper, in the February number of the American Journal of Science, that, during two years when he photographed the moon every moonlight night at Hastings-on-the Hudson, there were only three occasions when the air was still enough to give good results. Out of 1,500 lunar negatives, only one or two were really fine pictures.
Last summer, during a trip to the Rocky Mountains, he took with him a small achromatic, hoping to find more steadiness of the atmosphere at great elevations, but was disappointed. At Salt Lake City, 4,650 feet above the sea, Capella twinkled as badly, both to the naked eye and in the telescope, as he ever saw it at the sea-level.
At Fort Steele, near 7,000 feet elevation, Antares twinkled very much; and at Camp Douglas, 5,250 feet above the sea, the twinkling of several stars examined was surprisingly great.
At one point, however, he found the atmosphere without undulations, and the stars shone through it with a steady light. The central disk of Arcturus, he says, was hard and sharply defined; Antares near setting hardly twinkled at all; the moon was perfectly steady.
This point of observation was not far from Fort Steele, in the main range of the Rocky Mountains, at an elevation of 8,900 feet above the sea. Distant objects seemed near in the transparent air. The sky was not black, as he expected, but of a light blue; the moon, however, was near its full.
Another trial was made at Trout Lake, nearly 10,000 feet above the sea-level, and the air was found to be unsteady but transparent. At this point, however, intense cold, fierce winds, and heavy snow-falls, occur, making the location of an observatory here undesirable.
Dr. Draper concludes that the atmosphere in these high regions, although more transparent, is quite as tremulous as at the ocean-level at New York.
Influence of Heat on Galvanic Conductivity.—Till very recently it was held to be a law of Nature that the galvanic conductivity of all metals and metalloids is diminished by rise of temperature. It has been shown, however, that selenium is an exception to this rule, its conductivity being increased by heating. And now a further exception must be made in the case of tellurium, a body closely allied to selenium. We have already (in vol. x., p. 115) given an account of Siemens's researches on the action of light on selenium; we now present a synopsis of the results obtained by Franz Exner in his experiments with tellurium. Three bars of tellurium were prepared. Bar 1 broke before its dimensions were determined; bar 2 was 54 millimetres in length and 2.6 millimetres diameter; bar 3 was 153 millimetres in length and 3.73 millimetres diameter. Bar 1 was heated to 200° Cent., and then slowly cooled. The resistance increased up to 90°, and thenceforward gradually decreased. In cooling, resistance steadily increased from 200° down to the room-temperature. This increase was so great that at the end of the experiment the resistance was six times what it was at the beginning, temperatures being equal. The same bar having been again heated from 20° to 200° Cent., there was no turning point, and the resistance decreased steadily to the end, and increased continuously throughout in the cooling; but at the end the resistance was less than at the beginning.
Bar 2 behaved essentially like bar 1; the turning-point, however, was much higher, viz., 140°. With bar 3 five series of experiments were made, and with quite similar results. With the first heating there was a turning-point, which did not appear with after-heatings. At the maximum temperature, the resistance was pretty constant, while the resistances at the beginning and end of the experiments were very irregular.
Destruction of Germs at Low Temperatures.—Prof Tyndall, in a communication to the London Royal Society, shows how heat, when discontinuously applied, though the temperature be below the boiling-point of water, effectually sterilizes organic infusions. In all such infusions, he observes, there is a period of latency preceding their clouding with visible bacteria. During this period the germs are being prepared for their emergence into the complete organism. They reach the end of this period of preparation successively, the period of latency of any germ depending on its condition as regards dryness and induration. The author's mode of proceeding is this: Before the latent period of any of the germs has been completed—say a few hours after the preparation of the infusion—he subjects it for a brief interval to a temperature which may be under that of boiling water. Such softened and vivified germs as are on the point of passing into active life are thereby killed; others not yet softened remain intact. This process he repeats well within the interval necessary for the most advanced of those others to finish their period of latency. The number of undestroyed germs is further diminished by this second heating. After a number of repetitions, which varies with the character of the germs, the infusion, however obstinate, is completely sterilized. The periods of heating need not exceed a fraction of a minute in duration. Sum them up in the case of an infusion which they have perfectly sterilized: they amount altogether to, say, five minutes. Boil another sample of the same infusion continuously for fifteen or even sixty minutes, and yet it is not sterilized, although the temperature is higher and its time of application more than tenfold that which, discontinuously applied, infallibly produces barrenness.
Extinction of a Prehistoric Race.—The extinction of the partially civilized race who once dwelt in the Rocky Mountain region was probably the result of some great geological change. The country is naturally arid, but doubtless when this nearly-forgotten people dwelt here in the numerous cities whose ruins are still to be seen the conditions of life were more favorable. The annals of this interesting race have perished with them, and the history of their downfall is now matter for conjecture. Mr. F. S. Dellenbaugh, of the Buffalo Society of Natural Sciences, describes as follows the course of events which resulted in the extinction of the Shinumos: When the change occurred, "the inhabitants, not understanding the science of irrigation, beheld their crops slowly but surely failing every year. The inevitable result was famine. By this their hardy constitutions were weakened, and the way was prepared for some great epidemic that swept away thousands, and left them in a melancholy condition. Then the epidemic was, possibly, soon followed by the appearance of the Indian, so entirely different from the Shinumo. He was ferocious, treacherous, cunning. Lying, cheating, stealing, murdering, were his pastimes. Then, it is no wonder that the Shinumo, in his emaciated condition, was compelled to retreat before the impetuous attack of such a foe. He was no warrior—no hunter. He had depended almost entirely on his knowledge of agriculture for his peaceful existence. It was impossible for him to act on the defensive, and at the same time successfully till the soil. The Indian was constantly oh the alert to surprise him. He must fall back and yield more territory to the exacting intruder. Vanquished and discouraged, he fortified himself in places extremely difficult of access; built cliff-houses; lived in caves, and finally became extinct. The divisions on the south side of the Colorado fared somewhat better, for the stupendous chasms of the river form a barrier that can only be crossed with success at several widely-separated points. Consequently, when the Indian reached this obstacle, his easy progress southward was interrupted. The crossing-points, too, which of course were well known to the Shinumos, had been strongly fortified by their soldiery, and thus a double check was presented to the invasion. The people then enjoyed comparative peace, till, in the course of their nomadic wanderings, the Indians discovered that there was an end to the canon barrier, and were once more able to cope with their antagonists under favorable auspices. The Shinumos were again slowly driven back, and at the dawn of our knowledge of the region we find surviving only a mere handful of their kindred, in the Pueblo tribes, who were still defending their fortress-homes, as they had been for centuries."
Recent Outbreak of a Sandwich Island Volcano.—The volcano of Mauna Loa, Hawaii, was lately active for a few days, commencing on the evening of February 14th. A correspondent of the San Francisco Chronicle states that the outbreak was extremely sudden and violent:
How Science is advanced in Norway.—A correspondent of the London Times, à propos of the recently-published "Life of Thomas Edward," records an instance of liberal encouragement extended to a Norwedan naturalist. "Some years ago," says this correspondent, "there lived on the wild northwest coast of Norway a clergyman, with his wife, a large family, and a small income. He possessed two great advantages over Edward—a good education, and larger opportunities for observation. He, too, had the seeing eye, without which all opportunities are useless, and shortly it was known that science was being enriched by the hard-worked parish priest. The action of the Storthing was prompt. Though the majority of that body are poor peasants, and hold the purse-strings with a firm grip, they have the virtue of being liberal when good cause can be shown for it. They created a professorship of zoölogy in the Christiania University, endowed it with a salary equal to £1,000 in England, and appointed the clergyman to the professorship, but without requiring either residence or teaching. How the professor went on enriching science with his discoveries, how he trained up his sons to follow in his footsteps, two of whom are now professors in the Christiania University, all this is known to scientific men, nor will they require to be told that the name of the clergyman was Sars."
Sir Wyville Thomson on the Theory of Evolution.—Sir Wyville Thomson said, in a lecture to the natural-history class at Edinburgh University, that the great stumbling block, from the natural-history side of the question, in the way of an acceptance of the evolution hypothesis, was that any such passage from one species to another is entirely outside our experience. The horse had evidently been the horse since the earliest hieroglyphs were engraved upon Assyrian monuments and tombs; and the same held for all living creatures. There was not a shadow of evidence of one species having passed into another during the period of human record or tradition. Nor is this all. We have, in the fossil remains contained in the rocks, a sculptured record of the inhabitants of this world, running back incalculably farther than the earliest chisel mark inscribed by man—incalculably farther than man's existence on this planet; and although we find from the record that thousands of species have passed away, and thousands have appeared, in no single case have we yet found the series of transitional forms imperceptibly gliding into one another, and uniting two clearly distinct species by a continuous bridge, which could be cited as an undoubted instance of the origin of a species. Mr. Darwin's magnificent theory of "natural selection" and "survival of the fittest" has undoubtedly shaken the veil by pointing out a path by which such an end might be attained; but it has by no means raised it. Still, even if we never found out the precise mode in which one species gave rise to another, there could ba no further hesitation in accepting generally an hypothesis of evolution, and in regarding our present living races as the ultimate twigs of a great genealogical tree whose gradually coalescing branches we could trace, if our information were complete, to the dawn of geological time.
The Resources and Industries of Sudan.—At a late meeting of the Egyptian Geographical Society a paper on the Sudan was read, based on information collected by the late Munzinger Pasha. It was stated that there are few mountain-chains in the Sudan, but that granite ridges divide the region into well-defined districts, usually named after the rivers which flow through them. The country is, as a rule, fertile. The watercourses are mere torrents, which in summer are almost dry. The centres of population are few, and all the large towns are on the banks of the two Niles. Gold and copper are found, but the wealth of the country depends on agriculture and cattle breeding. The population numbers about 5,000,000, consisting of Arabs and negroes. Industry is very much developed, and only articles of luxury need be imported. Stuffs, sword-blades, and leather of a very superior quality, are manufactured. The exports are chiefly ivory, gums, skins, etc. The people are nearly all Mohammedans, but their religion is mixed with numerous heathenish superstitions.
Extermination of the Grasshoppers.—Prof. A. S. Packard, Jr., has written to the Tribune a communication in which he advocates the project of affording Government aid toward the extermination of the Rocky Mountain locust. Locust years, he observes, are years of unusual drought, and seasons of drought occur every seven or eight years. In such summers the locust breeds in untold millions, and, the supply of food being short, they fly off hundreds of miles. A swarm observed by Prof. Robinson near Boulder City, Colorado, traveled a distance of about 600 miles to Eastern Kansas and Missouri. When seen at Boulder the swarm was on its way from the north, and may have come from some part of Wyoming. The general direction of the winds in July and August, along the eastern slope of the Rocky Mountains and on the Plains, coincides with the course of these swarms. If we would intelligently study the causes of the excessive increase and migrations of the locust, we must examine the meteorological features of the Western country, ascertain the periods of drought and of undue rainfall, the average direction of the wind for the different months, in order to learn how far they correspond with the phenomena of locust-life. That there are cycles of dry and hot seasons recurring at irregular intervals, while the general average may remain nearly the same, century after century, is supported, though it may be vaguely, by observed facts. The author thinks that the remedy for locust visitations can be discovered and applied by a cooperation between the Signal Service and skilled entomologists employed by the General Government and the States most directly concerned.