Popular Science Monthly/Volume 34/April 1889/Popular Miscellany
Natural Purification of Polluted Streams.—The growing population of the many cities which discharge their sewage into rivers gives increasing importance to the question how great a degree of pollution is allowable in a stream of given flow, the water of which is to be used lower down for domestic or for manufacturing purposes. Mr. Rudolph Bering says that oxidation and decomposition of sewage matter was for a long time thought to be the main cause for the clarification of polluted rivers. To-day it is known to be but a minor cause compared with dilution and subsidence; and if the sewage is discharged in a fresh condition into a stream of water, its destruction is in part due to fish and other aquatic animals. Some of the refuse from stock-yards is disposed of, no doubt, in this way. Most of the decomposition, or oxidation as it is usually termed, of sewage is effected by the myriads of microscopic plants, microbes, or bacteria contained in both air and water, which at once seize upon the dead organic matter. For purifying the sewage discharged into a river, oxidation can be depended upon only to a limited extent, because of the comparative slowness with which it takes place. Subsidence of the heavier matter tends to clarify it before it flows many miles; dilution with a sufficient quantity of clean water prevents an offensiveness almost at once; but oxidation requires many days under continuous aeration of the river. From a comparison of data in regard to the actual purification of polluted streams we may draw the following inference: Rivers not to be used for water-supplies, but to be inoffensive to communities , residing a few miles below, to remain fit for ordinary manufacturing purposes, and to sustain the life of fish, may receive the sewage from one thousand persons for at least every one hundred and fifty to two hundred cubic feet of minimum flow per minute, supposing that natural subsidence of the heavier matter takes place immediately below the town discharging the sewage. Beyond the above limit it appears to be advisable to resort to land or other filtration, or to chemical precipitation. But the whole subject needs further investigation.
The Nebraska City Pontoon Bridge.—Colonel S. N. Stewart, of Philadelphia, has recently built a pontoon bridge for ordinary traffic across the Missouri River, at Nebraska City. It is 1,074 feet long, 2412 feet wide, and consists of a flooring laid upon boats which float upon the river and are securely anchored. The city has held a franchise for such a bridge for twelve years, but the project has been opposed by persons interested in steamboats plying on the river. Many predicted that the attempt would fail, for the Missouri River has a swift current, which here attains about its highest velocity, and large numbers of logs and trees are constantly drifting in the stream. These, however, are carried under the floats without doing any damage. In the channel of the river the bridge makes a V, pointing down stream, which is the draw. To open the draw, the connections at the point of the V are cast off, and the current swings the two sections apart, leaving a free opening 528 feet wide. It is the widest draw in any bridge ever built. The ends of the section are connected by a sunken steel-wire cable, and the draw is closed by winding this up on a capstan, worked by one man. There is a pontoon bridge across the Mississippi River at Prairie du Chien, the draw of which requires a powerful engine to close it. The bridge is to be removed each winter when ice covers the river. Both the pontoon bridge and a crib-work structure 1,050 feet long which crosses a second arm of the river were built in twenty-eight days, at a cost of about $18,000. For the spring floods it is proposed to greatly increase the strength of the steel anchoring cables. The bows of the boats are to be sheathed with iron, and the bottoms are to receive an extra planking of oak. A railroad bridge of steel crosses the river near the pontoon bridge. This was built between December, 1887, and June, 1888. Heretofore pontoon bridges have been little used except as a temporary expedient for military purposes; but their cheapness, and the satisfactory character of the draw and other details in the form just described, bespeak for them a more extended use.
Somali Traits.—The Somalis, as represented by Mr. F. L. James, who has traveled among them, are a curious people, hostile to Europeans, treacherous, "marauding, semi-civilized half-castes, offshoots of the great Galla race, allied to the Caucasian type by a steady influx of pure Asiatic blood. They are Mohammedans, but the rites of their religion sit loosely upon them. Although their trust is in Allah, they have been known to ask where he can be found, as some of them would like to catch him and spear him for having laid waste their homes and killed their wives and cattle. Yet they let off sudden prayers with great fervor during moments of anxiety." The hire of camels and drivers to the traveler was ratified by an oath that, if the man failed to keep the terms of the contract, he would divorce his wife. Mr. James had to engage women servants, because the men refused to build their own mat-huts or do any cooking. None of their fathers had done this, they argued, and were they to do the work of women the tribes through which they passed would despise them. At one place the people believed the caravan had descended from the heavens, and this was confirmed when Mr. James and the others began to smoke. "The pipe was part of ourselves, for how else could our mouths blow forth clouds, which would of course bring down rain?" The author explained that these clouds were not "water-bearers," but were due to plants lighted by harmless fire-makers," and to prove this one of the party struck a match and lit a fresh cigarette. This caused further bewilderment. The match had produced lightning, and of course the cloud could produce thunder; so the travelers were "storm-makers."
Healing of the Broken Bones of Birds.—It is not often that doctors are able to observe a broken bone almost in the very act of healthful healing, as has recently been the privilege of Dr. R. W. Shufeldt. He obtained on the same day a red-tailed hawk and a turkey-vulture which had been shot while high in the air with a 0·45 caliber government carbine; the ball in the former case passing clear through the chest, and in the latter case breaking in two the radius and the ulna. The hawk's wound could not be discovered, and the bird was apparently whole and vigorous. When killed and dissected, three weeks afterward, it was found that all of the costal ribs and the scapula had been broken across, but were now substantially healed. The ribs had individually made a good union and there was no anchylosis among them, and the blade of the scapula, though not perfect, was in essentially as good a condition as ever; the whole constituting a case of "a fearful wound with a truly magnificent recovery." The buzzard, besides having been shot, had been kicked about by the soldiers, "and was more dead than alive." It had recovered, and could fly well in about a week, when it was killed. The union of the bones was complete and firm, and a mass of callus was being rapidly absorbed at the sides of the fracture, while the bones had remained practically straight. From this and other cases within his experience, the author is convinced that, in case of fractures of the bones of the wings in birds, the good unions that result with hardly any deformity or shortening are largely due to the material assistance afforded by the quills of the primary and secondary feathers, which act as splints. Were this not the case, and if deformity ensued, the bird would be crippled in its power of flight, or deprived of it.
Food and Economical Plants of Abyssinia.—The most important of the food plants of Abyssinia is the taff (Poa Abyssinica ), a cereal bearing grains as small as a pin's head, from which the general bread is made. An inferior black bread is made from a kind of millet that grows in low grounds. Roasted flax-seed is sometimes eaten. The flower-stock of the plantain, cooked with milk and butter, is very tender, has the flavor of new bread somewhat underdone, and is an excellent dish. From the leaves of the ensete mats are made. The eeca, an asclepiad, furnishes a tough fiber, which is used in making cordage and twines. Other fibers, for various uses, are furnished by the bark of the Calotropis gigantea; and the tender leaves newly pulled from the stipe of the doum-palm are wound into all kinds of matting and basket-ware. The powdered seed of a large tree called herebera (Milettia ferruginea) is thrown into the water to stupefy fish, and makes it more easy to catch them. The chief articles of export are calves' hides, salted and dried, beeswax, ivory, tamarinds, ostrich-feathers, gutta-percha, gum arable, mother-of-pearl, leopard skins, musk, honey, and tobacco.
Interest in Reading.—The primary object of ordinary reading or study, Mr. Balfour holds, in his rectorial address at St. Andrews, is the enjoyment to be obtained by the possession and acquirement of knowledge. Knowledge is most easily attained in those subjects which we like most and take most interest in; and by that principle we should be directed to the kind of reading which we should take up. By the same principle we should not try to read the books on the list of the hundred or so best, merely because they are on the list; but when our interest is fixed on a particular line, the list is good to refer to for the best books bearing upon it. What interests the ordinary man at one time does not interest him at another; but "his interests change with the changes that are going on around him in the world. He sees some natural curiosity, reads something in the newspapers, hears of some incident or character in history, or goes to some place which awakens his interest and attention, and induces him to read. If the ordinary man, then, is to read what interests him, he is pretty sure to read widely, and therefore necessarily, since life is short, superficially. . . . Now, can it be said, that the man who reads like this, with freshness and vigor, eager to find out something, to get light on a subject dark to him before, will not get more knowledge, and so benefit himself vastly more, than the man who, with slow and painful steps, heavily plods through a list of books, though that list has on it all the masterpieces of creation?"
House-top Summer-Resorts.—A plan to make our house-tops useful is sketched by Dr. Gouverneur M. Smith, in a paper on "Wasted Sunbeams—Unused House-tops." The Oriental has no difficulty in the matter; he lives on the top of his house a considerable part of the year, and builds his roof with an especial eye to that sort of occupation. Why may not we? By pitching our tents upon them, or by taking them as they are, except that the roof-coverings would have to be made more solid, we might make our roofs comfortable sojourning-places and inexpensive summer health-resorts. "Roofing," says the author, "can be contrived suited to this climate, and enduring as pavement. A pleasure resort might ornament each residence, its limits bounded by the area of the dwelling; neighborly consent could widen the range, turf and flowers brightening the plan. Iron-framed and glass inclosed rooms or cupolas could be added, which would prove useful during all seasons, artificial heat tempering brumal inclemency. If such adaptation of house-tops would be an advantage to the affluent, who can escape city life during the summer, how much greater advantage would be secured to the tenement-house districts!. . . For the higher graded tenement-houses, such fresh-air facilities would be hailed with delight by the inmates. The proximity of open breathing-places to their rooms would endear their humble homes. Summer moonlight evenings could have a new aspect; and again, round a family lantern, groups might gather to read, sew, or engage in games, and thus a home-felt pleasure could quiet restless spirits, craving questionable or illicit amusements. More true enjoyment might be observed in such groups than on the piazzas of fashionable resorts. Landlords could arrange for the periodical sweeping of roofs, as well as of the halls and stairways, and, among a very large class of the respectable poor, pride would stimulate to a tidy and decorative care of their home parks." By a little alteration in structure the upper stories of houses, now stuffy places enough, could be made light and airy, and attractive as resorts or play-rooms in inclement weather. This recalls the papers contributed by Mr. Bunce in "Appletons' Journal" several years ago, in which a similar utilization of the roofs of the tall houses just then coming into fashion, or their conversion into gardens, was advised and illustrated with pleasing descriptions of what might be.
Adolf Sutro's Water-Power.—Mr. Adolf Sutro's aquarium at San Francisco, though at a higher level than the ocean, is fed by sea-water in sufficient quantities to furnish a strong constant stream by the action of natural forces only. How it is done has been told, in the California Academy of Natural Sciences, by Mr. Theodore H. Hittell, who indicates also what may be a new economical power. The aquarium is on the lee side of a jutting rock. Through this rock, and leading out to its exposed face, is a short tunnel, while on the face of the rock most exposed to the rollers of the ocean is an excavated hollow place or basin, the bottom of which is several feet above high-water mark. As the rollers come in they dash violently against the face of the rock, rise in mingled water and foam to a very considerable height, and splash over into the basin. The water thus caught in the basin does not fall back into the ocean, but runs through the tunnel into the aquarium and maintains its high level. Between that level and the level of the ocean in the cove, where there is no rock to dash against and no splashing, there is a fall, as indicated by the running stream, of several feet—enough to furnish very valuable water-power. The principle of gaining a head of water thus applied may obviously be made of great importance at many points along the coast. Though the main body of water to be caught is thrown up only during high tide, there is hardly any limit to the amount that may be thus secured, provided the basin is large enough and not too elevated.
Fast Railway-Trains.—Some remarkably fast time has been made recently by trains between London and Edinburgh, in consequence of a rivalry between the Northwestern and the Great Northern Railways. The journey formerly took nine hours, but last summer the former road reduced the time to eight hours and a half. Its rival then made it eight hours, and, on August 6th, the Scotch Express, on the Northwestern, covered the distance in eight minutes less. The times of the runs made without stopping on this trip were: Euston to Crewe (158 miles), 2 h. 56 m.; Crewe to Preston (5212 miles), 51m.; Preston to Carlisle (90 miles), 1 h. 38 m.; Carlisle to Edinburgh (10012 miles), 1 h. 45 m.; the average speeds attained being the highest yet reached. On the second day of the accelerated service, this train, consisting of an engine with six coaches, made the run from Crewe to Preston in fifty minutes, and that from Preston to Carlisle in ninety minutes. This is claimed as beating every previous record.
Sagacity of the Blood-hound.—The bloodhound is declared by Dr. Gordon Staples, from his own somewhat wide experience, to be one of the most sagacious of all dogs. His wisdom when quite a puppy is sometimes astonishing. When only six months old, he will often show to his master that he has already come to the conclusion that life is real and earnest, and not meant merely to romp and play in. I have had a puppy at this age take me quite in charge, as it were, giving himself all the airs and manners of a dog of seven years old, and going on watch at nightfall as serious as a sentry in an enemy 's country. He would look up in my face as much as to say: 'There's nobody in this wicked world worth a thought except you and me, master, and you don't count as far as defense goes; if you please, I'll do the watching for both.' As a rule, the bloodhound is most docile and willingly affectionate. He can be trusted with children; so much so, that a boy may safely do duty as the 'hunted man' when the hound is being trained in hill or forest. The animal is nevertheless suspicious of the motions of strangers; he therefore makes a most efficient guard either to person or to property." Both scent and sight are remarkably well developed in the blood-hound; the animal is beautifully formed all over for hard work, but does not excel in speed. In olden times he was called the "slow-hound," among other names, and when the trail was perceptible, even to human senses, the dog was taken on horseback to save time. Great value is put upon the hound's up-bringing and general treatment when not on duty. "If the creature has been reared and trained by a fool, and under the influence of fear—if he be not well kept, properly bedded, exercised, and fed, and allowed the companionship of man, he is certain to develop more or less of nervous debility, and ten to one will go wrong at the critical moment. , . . Some people doubt the possibility of dogs tracking a criminal through the streets and lanes and busy thoroughfares of a crowded city. They speak of cross-scents; but in doing so they speak of what they do not understand as well as—the blood-hound does. He has got the right scent at the right place, and, if he is the right sort of dog, he will stick to that and no other. Besides, it has been done over and over again."
Diet and Disease.—Dr. A. Hunter's new cook-book—"Culina Famulatrix Medieinæ; or, Receipts in Modern Cookery, with a Medical Commentary"—contains much plain speaking with reference to certain dishes which are supposed to contribute to the increase of the business of doctors. A certain giblet-soup is described as containing "a considerable amount of gout and scurvy." A mock-turtle soup is pronounced "a dangerous dish, and will soon bring a man to his crutches"; a second kind is denounced as "a most diabolical dish, only fit for the Sunday dinner of a rustic who is to work the six following days in a ditch-bottom"; and of a third, the author observes, "there is death in the pot." Other dishes of equally elaborate composition, and to the lay view as indigestible, are well spoken of; whence it may be inferred that the author is as prejudiced as scientific.