Popular Science Monthly/Volume 23/July 1883/Popular Miscellany

From Wikisource
Jump to: navigation, search
Popular Science Monthly Volume 23 July 1883  (1883) 
Popular Miscellany
 

POPULAR MISCELLANY.

Higher Professional Aims.—"The Higher Professional Life" was the subject of Dr. J. M. Da Costa's recent valedictory address to the graduating class of Jefferson Medical College, Philadelphia. The higher aim of the physician should be to add to knowledge and increase the resources of his profession. It may be sought in various ways: by making original inquiries in the way that Darwin and Pasteur have so brightly illuminated; by cultivating literary tastes, and thereby becoming quicker in perception and more skillful in disseminating truths once learned; by mixing in the great movements that are to benefit mankind, and becoming influential in them; and by becoming active for the advancement of sanitative and preventive medicine. "There are thus many ways in which the aspirations of a higher professional life may be realized in useful or in great work. Some of these can be followed only when success has brought comparative leisure; but all can be kept in mind; one or all can be aimed at throughout our careers, and according to our individual strength."

 

The Glacial Moraine in Pennsylvania.—We have already mentioned the fact that Professor H. Carvill Lewis has traced the great glacial terminal moraine along its whole course through Pennsylvania. An account of his investigations is given in a paper recently read by him before the Franklin Institute of Philadelphia. The moraine enters the State in Northampton County, at latitude 40° 49', and may be followed in a northwesterly direction till it enters New York from Potter County, at a height of 2,580 feet. It afterward turns at right angles to its former course, and, trending to the southwest, re-enters Pennsylvania at Pine Grove township, Warren County, whence it may be traced till it crosses the State line into Ohio at Darlington township, Beaver County, latitude 40° 50'. It thus leaves Pennsylvania at almost precisely the latitude at which it entered it; and, if a straight line were drawn across the State between these two points, the line of the moraine would form with it a right-angled triangle, whose apex would be a hundred miles distant from its base. The moraine crosses the Delaware at an elevation of 250 feet, the Allegheny River at an elevation of 1,425 feet, and the Beaver at an elevation of 800 feet above the sea, or 225 feet above Lake Erie. Upon the highlands it rises a thousand feet or more higher. The distinction between the glaciated portion of the State and the region south of glacial action is very marked, and the moraine itself is so sharply defined that at one point, Buck Mountain in Luzerne County, Professor Lewis was able to stand with one foot upon the glaciated and the other upon the non-glaciated region. The moraine is very finely developed west of Bangor, in Northumberland County, where it forms a series of "hummocky" hills one or two hundred feet high. Its course in Monroe County, as it winds from the top of the Kittatinny Mountain down to Cherry Valley, and then up again on to the Pocono, is a complete vindication of the glacial hypothesis. It is in no sense a water-level, nor could it have been formed by floating ice or by any other cause than that of a great glacier. It is wonderfully shown upon the summit of Pocono Mountain, over 2,000 feet above the sea, where a great ridge of moraine hills, twelve miles long, one mile wide, and 100 feet or more high, composed of unstratified till, and bearing numerous bowlders of Adirondack gneisses and granites, rises out of the plateau. The "kames" of Cherry Valley, with their accompanying "kettle-holes," and the terraces near Stroudsburg are also interesting features. Immense as was the power of the slowly moving glacier, says Professor Lewis, "it had but slight effect upon the topography of the country. It is a mistake to suppose that glaciers can level down mountains or scoop out canons. The glacier had merely 'sand-papered' the surface of the rocks."

 

Joseph Duncan Putnam.—Joseph Duncan Putnam, late President of the Davenport (Iowa) Academy of Natural Sciences) who died December 10, 1881, had accomplished a remarkable amount of scientific work during his short life of twenty-seven years. lie was born in Jacksonville, Illinois, in 1855; began making a collection of insects when eleven years old, and tempted their scientific classification in his fourteenth year. At the same time he was interested in other branches of science and collections. In 1872 he spent three months in the mountains of Colorado with Dr. C. C. Parry; in 1873, five months as meteorologist to Captain Jones's Yellowstone expedition. The next year he spent chiefly in Colorado, completing a series of expeditions in which he collected altogether 25,000 specimens of insects, many of them very rare. From 1869 he was one of the most active and useful members of the Davenport Academy, and was in succession its recording secretary, corresponding secretary, and president; and he sustained a large share of the burden of the editorial supervision and publication of its "Proceedings." Mr. Putnam's scientific publications were not voluminous. With one or two exceptions his most important investigations were never fully elaborated, and were embodied only in notes, letters, and incomplete manuscripts. A list of twenty-one is given, of which the most valuable are papers on bark-lice, and on his investigations of the Salpugidæ, a group intermediate between the scorpions and the spiders. A paper by him on "Insects and Flowers of Colorado" was published in the tenth volume of "The Popular Science Monthly."

 

Getting Water in the Desert.—The supply of water always formed a principal question, and often a preponderant one, during the marches of the French troops in Algeria and Tunis. Rivers having a permanent supply of water are very rare in those countries, but wadies—beds of torrents, generally dry, but full after a shower are numerous. The most ordinary supplies of water were sedirs, or puddles of rain-water held in natural basins of clay or stone, near which the camps were pitched whenever they were accessible. They are to be found in the beds of wadies, and sometimes in slight depressions of the plain, where they are frequently of considerable extent. When full they contain, notwithstanding they are so shallow, prodigious quantities of water, which is, however, exposed to an enormous evaporation, so that it does not last long. These natural reservoirs have been covered with sand in many places, where a permeable bed several feet high has been formed, with a dry surface corresponding with the general level of the surrounding land. It is only necessary to dig a hole, and wait a little while, for the water to rise to a certain level, forming a kind of extemporaneous well, which the Arabs call an oglat. These wells contain but little water, and are soon dried up when drawn from, but will become filled again in the course of a few hours. These resources, precarious at the best, are often wanting; but the country is full of ruins, attesting the former existence of a large population, and among them are many useful structures, including well-made cisterns still almost entire, and very deep. Water is got from them by going down steps to the surface, or by means of a device called the guerber, which is in general use. This is a leathern bottle, adjusted at the curb of the well by means of pulleys and ropes, which are worked in such a manner by a man and an ox that the vessel goes up and down, fills itself with water and empties itself, without any one having to handle it directly.

 

Symptomatic Anthrax and Disinfectants.—The Lyons "Médicale" publishes the results of some valuable experiments which have been made by MM. Arloing, Cornevin, and Thomas, on the influence of various disinfecting agents on the virus of symptomatic anthrax. If the contents of a tumor in this disease be allowed to dry slowly at a temperature of 35º Cent, (or 95º Fahr.), a residue is obtained in which the organisms of anthrax retain their full activity. Water, through which a little of the residue is diffused, has a virulence not inferior to that possessed by the fresh virus, and which continues for at least two years. It was found, in carrying on the experiments, that the resisting power of the dried virus is much greater than that of the fresh. Whatever destroys the dried is capable of destroying also the fresh virus, while the converse is not true. The following substances were found to have no effect even upon the fresh virus: alcohol saturated with camphor or carbolic acid, glycerine, ammonia, acetate and sulphate of ammonia and sulphate of ammonium, benzine, a saturated solution of chloride of sodium, quicklime and lime-water, polysulphide of calcium, a one-in-five solution of chloride of manganese, a one-in-five solution of sulphate of iron, a one-in-five solution of borate of soda, a one-in-five solution of tannic acid, a one-in-ten solution of sulphate of quinine, a one-half solution of hyposulphite of soda, essence of turpentine, and monobromide of camphor; of gases, ammonia, sulphurous acid, and chloroform. A saturated solution of oxalic acid, a one-in twenty solution of permanganate of potash, a one-in-five solution of soda, vapor of chlorine, and sulphide of carbon, destroyed the fresh virus, but had no effect on that which had been dried, while the activity of the latter was destroyed only by solutions of carbolic acid (two per cent), salicylic acid (1 in 1,000), nitrate of silver (1 in 1,000), sulphate of copper (1 in 5), boric acid (1 in 5), saturated salicylic alcohol, corrosive sublimate (1 in 5,000), and bromine vapor. Thus many substances, unanimously regarded as antiseptic, were without effect upon the virus, even in the fresh state. This is the case with pure and camphorated alcohol, with which surgeons are accustomed to wash their instruments, quicklime, with which dead bodies are consumed, etc.

 

The Poisons in Tobacco-Smoke.—Herr Kissling, of Bremen, has published a useful paper on the poisonous constituents of tobacco-smoke, among which he specifies as strong in quality, carbonic oxide, sulphureted hydrogen, prussic acid, picoline bases, and nicotine. The first three substances, however, occur in such small proportions, and their volatility is so great, that their share in the action of tobacco-smoke on the system may be neglected. The picoline bases, too, are present in comparatively small quantity; so that the poisonous character of the smoke may be almost exclusively attributed to the large proportion of nicotine present. Only a small part of the nicotine in a cigar is destroyed by the process of smoking, and a relatively large proportion passes off with the smoke. The proportion of nicotine in the smoke depends, of course, essentially on the kind of tobacco; but the relative amount of nicotine which passes from a cigar into smoke depends chiefly on how far the cigar has been smoked, as the nicotine-content of the unsmoked part of a cigar is in inverse ratio to the size of this part that is, more nicotine the shorter the part. Evidently, in a burning cigar, the slowly advancing zone of glow drives before it the distillable matters, so that in the yet unburned portion a constant accumulation of them takes place. More, relatively, of this substance passes into smoke in the case of cigars that are poor in nicotine than in the case of cigars with much of that substance. Nicotine, notwithstanding its high boiling-point, has remarkable volatility.

 

Fisheries of New York.—According to the reports of the Census Bureau, New York is fourth in the list of fish-producing: States the value of its products being $4,380,565, but it holds a still more prominent position in several special branches. Its menhaden fisheries are more extensive than those of any other State, its yield of the products of that branch being more than half that of the whole country. The value of its oyster-products, $1,577,050, is greater than that of any of the other States, except Maryland, Virginia, and New Jersey. It returns the largest quantities of clams, both hard and soft; and it ranks third in respect to the shad-fisheries. Seven thousand two hundred and sixty-six of its inhabitants, and $2,629,585 of capital are engaged in the fishing industries.

 

Liquid Air and Solid Alcohol.—M. Cailletet, a French chemist, some time ago succeeded, by liquefying ethyline and causing it to boil, in producing a temperature of—105º C. (—157º Fahr.), at which he liquefied a few gases under strong pressure, and even caused oxygen to approach the liquid state. M. Wroblewski, of Cracow, one of his pupils, continuing the experiments, has, by boiling liquid ethyline in a vacuum, produced a temperature of—136ºC.(21245º Fahr.), at which sulphuret of carbon and alcohol were congealed, and oxygen and nitrogen became liquid. The change in the form of oxygen was obtained on the 9th of April in three experiments in which the conditions of pressure (2212 to 2612 atmospheres) and temperature were slightly but not essentially varied. Liquid oxygen is transparent and colorless, differing in this from ozone, which is deep blue. Liquid nitrogen has a similar appearance. Sulphuret of carbon is a white solid at—116º C., but becomes liquid when raised to—110º C. At—130º C., alcohol assumes the form of a white solid, which becomes viscous at—129º. Carbonic oxide was liquefied under similar conditions with nitrogen.

 

Ancient Cities in Guatemala.—Mr. A. P. Maudslay, at one of the recent meetings of the London Geographical Society, described some ruined cities in Guatemala which he had visited during parts of the winters of 1881 and 1882. At Quirigua, not a very great distance from Livingstone, the Atlantic port of the country, the ruins consist of raised terraces or mounds, usually faced with stone, and elaborately carved monoliths, representing human and animal figures, situated near them. The upright monoliths measure from three to five feet across the sides, stand from twelve to twenty-five feet out of the ground, and bear human figures, of which the heads are sculptured in high relief, and are usually surmounted by grotesque masks, whence spring elaborately carved head-dresses. The body and dress are covered with the most intricate and elaborate ornament, in which small human faces and grotesque forms frequently occur. Of the animal-shaped stones, some had curved claws and indications of armor like that of an armadillo, and held a human head, apparently the head of a woman, between their jaws. The largest of these stones, which was estimated to weigh about eighteen tons, represented a turtle, whose head was replaced by a huge grotesque human head, while in place of its tail was a life-sized figure of a woman sitting cross legged, and holding in her hand a manikin scepter somewhat resembling the children's toy of a monkey on a stick. The whole surface of the stone was covered with a profusion of ornaments. All of the monuments bore hieroglyphics and carved tablets— probably symbolical—of curious character. At Tikal, in the extreme northern part of the state, all the houses were made of stone, and coated with plaster, with walls about three feet thick, and the roofs built in the form of gables, without any attempt at an arch. The most imposing buildings are the five temples raised on almost pyramidal foundations. Beams of sapota-wood were used in supporting the building, and many of them remain in various states of preservation, while all were elaborately carved. The ruins of Usumacinta, on the river of the same name, and on the border of the Mexican State of Chiapas, were visited for the first time. The houses are more spacious than those at Tikal, and the lintel beams are of stone, and handsomely carved. One of the houses, which is described as a typical specimen, is built on a succession of terraces; the first terrace, seventy-three feet long by seventeen feet broad, has three doorways, each with a rather poorly carved stone lintel, and is finished off with a projecting cornice. Above it is a second course of eleven feet of stone-work, and over this is a hollow superstructure, looking like a pigeon-house with numerous pigeon-holes. The entire height of the building is about forty-two feet. The whole house has been covered with stucco, and painted in various colors. On the second story are three large and eight small panels, which once held human figures molded in plaster; and in the center of the "pigeon-hole" course is another panel, which once contained a figure of more than twice the size of life. Only parts of these figures now remain, but enough to indicate what they were. Inside the house is a great stone idol, twice the size of life, well carved and sitting cross legged, with its hands on its knees, like the figures of Buddha; the remains of a canopy of ornamental plaster-work were found near it. Remains of circular stone altars were found in different parts of the ruins, and earthen pots, partly filled with some half-burned resinous Substance. The Lacandone Indians, who live here, speak the Maya dialect of Yucatan, and were observed to be lighter colored than Mr. Maudslay's Indian workmen, and to have thick lips, a prominent nose, and an extraordinary receding forehead, nearly resembling the foreheads represented on the carved stones. Their only weapons, so far as Mr. Maudslay could see, were stone-tipped arrows. Their communities were often at war with each other, generally on account of the efforts of one or the other to carry off women. The pots of half-burned incense found in the ruins and near the idol, some of which were comparatively fresh, are supposed to have been made and brought by them; and the suggestion is offered that it is the fact of these Indians still holding in reverence the temples built by their ancestors and offering incense in them that has led to the current Central American belief in the existence of one of the ancient cities still existing hidden somewhere in the forest. The mythic city has been gradually driven farther back, and this river, the Usumacinta, now marks about the last place where it could be looked for.

 

Lightning-Rods.—A committee, representing several societies interested in the subject, which was appointed some time ago to inquire into the best method of constructing and adjusting lightning-rods, has recently made a most valuable report, based upon all the information it was possible to procure. Inasmuch as sharp points, even if made of platinum, are liable to be melted and blunted, the report recommends that the rod should preserve its full diameter nearly to the extremity, and be merely beveled off. To preserve the sharp points for drawing off the silent discharges of electricity, the attachment of a copper ring, bearing three or four needles of suitable size, at a distance of about a foot below the extreme top of the rod, is suggested. Vanes, finials, and other ornamental ironwork on the upper part of a building, must be metallically connected with the conductor. A coronal, consisting of a copper band, with stout copper points, each a foot long, at intervals of two or three feet on its circumference, is recommended for the chimneys of factories. Copper is preferred to iron as the material for rods, chiefly because it is less liable to be injured and rendered inefficient by rust. The diameter should be three eighths of an inch for copper rods, half an inch for copper rope, and nine tenths of an inch for iron rods. The rods should not be insulated from the building, but should be attached to it by fastenings of the same metal as the rod itself. A good earth-connection is specially important. In towns, connection with the iron water and gas mains is recommended, but not with lead pipes, because they are too liable to be melted. As a general rule, the lower end of the conductor should be soldered to a plate of the same metal as itself, having an area of not less than a square yard, while the hole in which this plate is sunk must be so deep that the earth surrounding the plate shall be moist even in the driest weather. Drains and water-courses may be utilized for keeping the plate in connection with a large extent of moist earth. It is recommended that the height of the rod be such that a cone having its vertex at the upper terminal, and its sides sloping at forty-five degrees, shall inclose the whole building, or as much of it as this particular rod is required to protect.

 

Too Long School-Sessions.—A governmental commission in Alsace-Lorraine for the investigation of the sanitary conditions of school-life has made a report in which, besides noticing the unfavorable conditions that usually receive attention in such documents, stress is laid upon the fact that the principles of mental education have not partaken during late years of the progressive improvement which has characterized most branches of knowledge. Thus, the greater variety in the instruction which is imparted by modern education fails in many cases to accomplish its purpose, and is of advantage only to pupils of more than average capacity. Much evil is believed to arise from school-children remaining too long in a cramped or otherwise restrained position, and from the excessive and premature strain to which the youthful brain is often subjected, while the dangers of moral and physical infection are always present. Improvements in the ventilation and sanitary arrangements of schools, however important in themselves, are, it is urged, of comparatively little use, when the pupil is kept for too long a time every day in a combined state of bodily inactivity and mental tension.

 

Schools and Infectious Diseases.—The question is sometimes presented whether it is expedient to close a school, among some of the pupils of which infectious diseases have appeared. The fact that the conditions and customs of school associations give facilities for the dissemination of contagion which are quite unknown in any other phase of social life often makes it seem that the closing of the school is indispensable to the checking of the disease. The necessity of such an extreme measure may, however, be nearly always prevented by the exercise of proper foresight. The teacher should be watchful of absences and their causes, and should give notice, when infectious disease is in question, to the proper officers. The sick pupil should then be isolated from the well ones, and his home and family surrounded with the most rigorous sanitary precautions for not less than eight weeks. Dr. David Page, sanitary officer of Westmoreland, England, has always avoided the necessity of extreme measures by adhering to these principles. The school should be closed only when it has obviously become a starting-point of infection, or when the control specified above can not be exercised. The term of suspension must be determined by circumstances, and can not be previously regulated, but a premature reopening should be avoided; and the reopening should be preceded by a thorough disinfection, by fumigation with sulphur and washing the walls with lime and the wood-work with soap and carbolic acid. The continuance of day schools during the prevalence of scarlatina is justified, says Dr. Page, when the children would be otherwise exposed to much risk in playing about their doors with children of infected families, and with those barely recovered from illness. Under such circumstances, always provided that due supervision over infected families is maintained, a child runs less risk in regular attendance at school. But in scattered country districts, where the children coming from all points are brought together only during school hours, the breaking up of the school is the best and safest course.

 

Earth-Tremors.—The committee appointed by the British Association, two or three years ago, to measure the lunar disturbance of gravity, have met with unexpected difficulties in the accomplishment of their task, and have substantially given it up as for the present unattainable. The Messrs. Darwin, who undertook the observations at Cambridge, found that, as soon as they had made their instrument sensitive enough to record the lunar disturbances, they had to deal with other disturbances, "so incessant and so lawless that the steady march of the lunar swing was utterly overborne and lost." The earth was never really still. It quivered and throbbed and warped and bent under the pendulum night and day, and even, as it seemed, in the absence of all merely local agencies that could be detected. A situation at the bottom of a deep mine was then suggested, but with no better success. The earth yields there under the operation of deep-reaching causes that can not be got rid of, and which produce effects of the same order of magnitude as the direct effect of the moon, and are at present inextricably entangled with it. These causes are the varying mass of the air, that shifts and changes according to the indications of the barometer, and the varying mass of the water on the shores, that shifts and changes with the tides. It is easy enough to believe that, when a mountain-mass is set down upon the earth, the crust must yield and a depression form at the spot upon which the excess of weight is placed. "But it was probably never imagined till now that, when the barometer rises an inch over a land area like that of Australia, the increased load of air sinks the entire continent two or three inches below the normal level. Over a like sea area the water surface may be depressed a foot or more. Thus, as the mass of air sweeps in wind or creeps by slower convection from place to place, the yielding earth sways up and down beneath its weight"; a depression is formed, toward the center of which the surface slopes from all sides, and the plumb-line ceases to be perpendicular to the surface. The mass of air which hovers over the spot also acts like a mountain and draws the pendulum toward it; the two effects are superimposed, and the apparent displacement of the vertical is exaggerated. The two influences always act together, and are proportional; and this twofold deviation is of the same order as that which the moon produces, but is perpetually varying and incalculable. It therefore vitiates all pendulum observations. The tides exercise a similar power, depressing the shore at the flood and allowing it to rise at the ebb. The advance and retreat of the water will also tell on the plummet by mere attraction. The lead will seem to be pulled seaward at high water, and will swing back landward at the ebb. At sixty miles away from the Atlantic coast the deflection due to tidal action of this kind is probably quite as great as the greatest deflection due directly to the moon. These flexures are not confined to the surface, but must extend in almost equal degree beyond the depth of the deepest mine. Until the atmospheric pressure and the state of the tides at each moment can be accurately known for a great distance around any given spot, the experimental determination of the lunar disturbance of gravity is out of our reach; our instrument, even in the most favorable site, must needs record incessant variations of which no satisfactory account can be given. A gravitational observatory must, therefore, for the present content itself with registering the more or less irregular tremors of the earth that are allied with earthquake-movements.

 

English and Metric Measures.—The following comparative summary of English and French (or metric) standards of measures and weights will be useful: The English inch is equivalent to 2·54 centimetres; the foot to 30·48 centimetres; the yard, to 94·44 centimetres; the mile to 1609·33 metres; the nautical mile, to 1852·30 metres.

The square inch is equivalent to 6·45 square centimetres; the square foot, to 929·01 square centimetres; the square yard, to 8364∙13 square centimetres.

The cubic inch is equivalent to 16∙387 cubic centimetres; the cubic foot, to 28·516 cubic decimetres; the cubic yard, to 764·535 cubic decimetres; the pint, to 0·567 cubic decimetre; the gallon, to 45·410 cubic decimetres.

The English grain is equivalent to 64·799 milligrammes; the ounce avoirdupois, to 28·349 grammes; the pound, to 453·590 grammes; the ton, to 1016·050 kilogrammes.

The foot-pound is equivalent to 0·13825 kilogrammetre; the French horse-power, to 75 kilogrammetres a second; and the English horse-power (550 foot-pounds a second, or 33,000 foot-pounds a minute), to 76 kilogrammetres a second.

The metrical unit of pressure is the kilogramme per square centimetre. We may also count by centimetres of mercury or by atmospheres. A pressure of one atmosphere corresponds to a column of mercury 76 centimetres high, or to 1·033 kilogramme per square centimetre. The English pound per square inch corresponds with 70·3 grammes per square centimetre.

 

False Fangs in Harmless Snakes.—The blowing-viper or puffing-adder of the United States, although it is timid and unaggressive, and can rarely be provoked to bite, and then does no particular harm, has been reputed a dangerous and venomous reptile because it has long, fang-like posterior teeth. It belongs to the genus Heterodon, which is so called on account of this unusual and irregular dentition. It is of the same group as the Xenodons, or strange-tooths, of tropical America, which are also supposed there to be poisonous, possibly for no better reason than our North American genera are. Dr. Stradling allowed one to bite him, and suffered no ill effects from the wound. Mrs. Catharine C. Hopley states, in "Land and Water," that she has lately examined one of these strange-toothed snakes for the purpose of seeing the fangs, when she observed that they are mobile, or what are called in the viperine snakes hinged teeth—that is, they are so set that the snake can erect or depress them at pleasure by a volitional movement of the jaw. It is known, she says, that no poison-gland exists in this snake, "and it was only on venturing to feel the teeth, in order to judge of their relative sizes, that the reptile let me know it had a larger pair safely tucked away in case I took too many liberties."