Popular Science Monthly/Volume 16/January 1880/Popular Miscellany
Education of the Color-Sense.—Though it is but a few years since general attention lias been directed to the subject of color blindness, the study of its phenomena has shown that there are two forms of the defect, not perhaps sharply separable, but nevertheless quite distinct. In one form there appears to be simply an imperfect or undeveloped sense of color, the power of distinguishing the different colors, though not wholly absent, being far below the normal. In the other form of the defect there is an entire inability to recognize one or more of the primary colors—that is, the blindness is complete so far as particular colors are concerned. Dr. Swan M. Burnett, surgeon in charge of the Ophthalmic Division of the Central Dispensary in Washington, in a short paper entitled "A Systematic Method for the Education of the Color-Sense in Children," expresses the opinion that cases of the first-mentioned variety are susceptible of decided improvement by early and persistent training of the individual. In cases of the other kind, however, which are generally hereditary, he believes that amelioration can be brought about, if at all, only by a course of education applied to successive generations. The author finds fault with the general neglect of the subject in our schools, and also with | the methods practiced in the few instances where such training has been attempted. In the Washington schools the practice is to use a chart on which the various colors are painted. These colors soon become so faded and dim as to no longer represent what was originally intended; and, even with this imperfect chart, no systematic instruction is given in the comparison of the colors. The first requisite, in Dr. Burnett's opinion, for teaching color to children is, that the method shall be simple and easy. The study should also be made interesting, so that the children will pursue it more as a diversion than a task. Each child should be taught separately, but the instruction may be carried on in such a manner that the other children can participate. As the main object is to enable the child to discriminate between the various colors, the comparison of one color with another will be the principal part of the work. But the pupil should at the same time be taught the names of the colors and shades, so as to be able to convey the impressions he has received in definite language. To carry out these indications in a simple and effective way, there are required—first, a set of sample colors with which comparisons are to be made; and, second, a collection of colors from which the pupil may choose such as are to be compared with the sample. For the former. Dr. Burnett recommends the following: "Take a half-sheet of white perforated cardboard (42 x 26 cm.) with the largest size perforations, and work into it, with Berlin wool, bars 18 cm. in length and 35 mm. in width, of each of the following colors: red, green, and blue, with a distance of 1·5 cm. between them. These should be as pure as possible, and represent the three primary colors. Then, beginning 3 cm. below, work in at the same distances apart each of the following colors of medium shade and as pure as can be got: purple, orange, yellow, pink, brown, and gray. A single skein of Berlin wool is generally enough to work a bar of the required length and width, which is sufficiently large to be seen distinctly across any ordinary schoolroom by a normal eye. This card is to be placed on a white background on the wall in sight of all the pupils." In the process of instruction the pupils are first familiarized with this card, and with the names of the colors represented on it, and, when able to designate each of these correctly, the teacher will explain what is meant by a "shade," and, taking a package of Berlin wools containing all the shades of the nine colors on the card, will pick out and exhibit to the class all the shades of one of the colors. After this, the shades are thoroughly mixed with the other colors in the pile, and the pupils are then called upon to do the choosing, arranging them in regular order from darkest to lightest. The same process is to be repeated with each of the colors on the card.
Population of Africa.—Accurate statistics of the population of Africa, and especially of the interior portions of the continent, are of course not yet obtainable, and it will probably be many years before several of the populous districts now known will be sufficiently accessible for a thorough census; but much important information has been gathered about the distribution of the inhabitants and the density of the population in the different parts of the country. In the region of the great lakes, for example, there are countries as thickly peopled as many of the states of Europe—relatively small areas which, according to Stanley, possess millions of inhabitants. Behna states that the negro regions are by far the most populous, while the desert parts represent the other extreme. M. A. Rabaud, in a paper published in the "Bulletin of the Marseilles Geographical Society," gives the following as the population of the different subdivisions of the continent: In the Soudan, the population is estimated at 80,000,000, or about fifty-three per square mile; the town of Bida, on the Niger, contains 80,000 inhabitants. The population of East Africa is estimated at 30,000,000, and that of Equatorial Africa at about 40,000,000. One of the latest authorities divides the population as follows among the great families into which ethnologists have separated the peoples: Negroes, 130,000,000; Hamites, 20,000,000; Bantus, 13,000,000; Foolahs, 8,000,000; Nubians, 1,500,000; Hottentots, 50,000. This would give a total population of 172,550,000. These figures are, of course, only approximate, and both German and English geographers think them too low, the former estimating the population at 200,000,000.
About Herrings.—From statistics of the Scottish herring-fisheries, furnished by a writer in "Chambers's Journal," we may get a partial idea of the enormous productiveness and abundance of that species of fish. During a recent year the herrings taken in Scottish waters and cured were sufficient to fill one million barrels, each barrel containing an average of seven hundred fish. This quantity it must be observed represents cured fish only, and only those which are caught in Scotland under the superintendence of the Fishery Board. It is pretty certain that as many herrings are captured and offered for sale as fresh fish and "reds" as are cured for the markets in Scotland and offered for sale as salt herrings; which gives us the prodigious total of fourteen hundred millions withdrawn annually from the sea; and even this number, vast as it is, does not include what are used in the form of white-bait, or those which are sold as sprats.
After draining the sea to such an extent, it might almost be supposed that there would be scarcely herrings enough left to suffice for a breeding-stock; but the demands of man are a mere fraction of what are taken out of the shoals. All that are captured, as well as all that are wasted during the capture, and destroyed in the process of curing, sink into insignificance when compared with the vastness of the quantities which are devoured by other enemies of the fish. Cod and ling are known to prey extensively on the herring; and a calculation, based on the number of cod and ling annually caught under the auspices of the Scottish Board of Fisheries (three million five hundred thousand were taken in 1876), assumes that there is a capital stock of these fish in the Scottish firths and seas of seventy million individuals; and that each individual consumes four hundred and twenty herrings per annum, which at the rate of two herrings every day for seven months in the year, shows a consumption of twenty-nine thousand four hundred million individual herrings. Nor does the account stop at this point. The commissioners who recently collected information on the Scottish herring-fisheries, assume that in Scotland alone the gannet (a sea-bird) will annually draw on the shoals to the extent of one thousand one hundred and ten million herrings! In addition to dog-fish, cod, gannets, and other sea-birds, the herring has many other enemies; porpoises, seals, coal-fish, and other predaceous fishes are constantly lying in wait to fall upon and devour them. A female herring, we know, yields over thirty thousand eggs; but at the shoaling-time myriads of those eggs are devoured by a variety of enemies; besides which, hundreds of thousands of the eggs are never touched by the fructifying milt of the male fish, and so perish in the waters.
A Fabled Eastern City.—In a communication to the Royal Asiatic Society of Bombay, M. C. Doughty gives an account of a visit to the so-called rock city of El-Hejjer, which lies upon the Haj road in Arabia, at twenty camel-journeys' distance from Damascus, and about which many extravagant stories are current among the Arabs. In the days of Ptolemy, who calls it Egra, the place was an emporium on the trade-road of gold and frankincense to Syria. Having got there after great fatigue, Mr. Doughty found the fabled seven cities of the Arabs—said to be hewed in as many mountains—to be about a hundred funereal chambers excavated in the sandstone rocks. The city appears, by the traces remaining of foundations, to have been a cluster of four or five palm villages in clay, each surrounded by a wall in the ordinary Arab fashion. In their interiors the funereal monuments are plain sepulchral chambers with sunken tombs in the floor and recesses, while in the walls are shallow shelves of a man's length. Inscriptions are seen handsomely engraved in a panel above the doorways in many of the monuments. Above these again, in the nobler monuments, there is very commonly the thick figure of a bird with outstretched wings. The Arabs say it is a buzzard or a falcon, but Mr. Doughty suggests that the effigies are those of the mortuary owls of the old Arabians. Mr. Doughty's visit has disposed of the singular fables propagated by the Arabs as well as by Turkish and Persian pilgrims, and which, he says, have been accepted in some works of learned Orientalists in Europe.
Cases of Remarkable Precocity.—From an entertaining paper in "Chambers's Journal" we select a few instances of "precocious cleverness." Anne Maria Schurmann was, in her day, the boast of Germany. At the age of six, and without instruction, she cut in paper the most delicate figures; at eight, she learned in a few days to paint flowers, which, it should be added, were highly esteemed; and two years later it cost her only five hours' application to learn the art of embroidering with elegance. Her talents for higher attainments, we are told, did not develop themselves till she was twelve years of age, when they were discovered in the following manner: Her brothers were studying in the apartment where she sat, and it was noticed that, whenever their memories failed in the recital of their lessons, the little girl prompted them without any previous knowledge of their tasks except what she had gained from hearing the boys con them over. In her education she made extraordinary progress, and is said to have perfectly understood the German, Low-Dutch, French, English, Latin, Greek, Italian, Hebrew, Syriac, Chaldean, Arabic, and Ethiopian languages. Her knowledge of science and her skill in music, painting, and sculpture were also extraordinary; and her talent for modeling was shown by the wax portrait she contrived to make of herself with the aid of a mirror.
Another prodigy was Dorothy Schlozer, a Hanoverian lady, who was thought worthy of the highest academical honors of the University of Göttingen, and had the degree of Doctor in Philosophy conferred upon her when she was only seventeen years of age. Before she was three years old she was taught Low-German; and three years later learned French and German; and, after receiving ten lessons in geometry, was able to answer abstruse questions. Other languages were next acquired with singular rapidity; and before she was fourteen she knew Latin and Greek, and had become a good classical scholar. She also made herself acquainted with almost every branch of polite literature, as well as many of the sciences. As an instance of this lady's indefatigable industry, it may be mentioned that she visited the deepest mines in the Harz Forest in the common garb of a laborer, to gain proficiency in mineralogy.
It is said that Blaise Pascal, one of the most profound thinkers and accomplished writers of France, exhibited precocious proofs of genius, especially in mathematics, from his earliest childhood. Having been purposely kept in ignorance of geometry, lest his propensity in that direction should interfere with the prosecution of other studies, his self-prompted genius discovered for itself the elementary truths of the forbidden science. When quite a boy, he was discovered by his father in the act of demonstrating on the pavement of an old hall where he used to play, and by means of a rude diagram he traced with a piece of coal a proposition which corresponded to the thirty-second of the First Book of Euclid. At the age of sixteen he composed a tractate on conic sections, which excited great admiration. Three years later he invented his celebrated arithmetical machine; and at the age of twenty-six he had composed the greater part of his mathematical works, and made those brilliant experiments in hydrostatics and pneumatics which ranked him among the first natural philosophers of his time.
Discrimination and Memory of Sounds.—Some very extraordinary feats of memory are by the "Scientific American" credited to a youth named Hicks, residing in Rochester, New York. Hicks has not lived long in Rochester, having removed thither lately from Buffalo; yet he is able to give the numbers of nearly three hundred locomotives on hearing their bells. During the day he is employed at so great a distance from the railway that he rarely hears a passing train; but at night he can hear every train, as his house is situated near the railroad. Men who have for years been connected with railways admit that at most they can distinguish the sounds of only very few locomotive-bells as compared with the great number Hicks can name almost without thought. Not long ago an old switch-engine, used in the yards at Buffalo, was sent to Rochester for some special purpose. As it passed near Hicks's house he heard the bell, and remarked that the engine was number so-and-so, and that he had not heard its bell for six years. A boarder in the house ran to the railroad and found that the number given was the correct one. Not long since the young man went to Syracuse, and, while there, hearing an engine coming out of the round-house, remarked to a friend that he knew the bell, though he had not heard it in five years. The number which he gave proved to be the correct one.
Lubbock on Science in the Primary Schools.—Sir John Lubbock, advocating in the British House of Commons the cause of science-teaching in schools, urged that elementary science should be placed on an equality in the education-code with grammar, geography, and history. The practical difficulties in the way could be easily overcome, and his proposal, so far from upsetting the equilibrium of the code, would really establish it, seeing that, at present, the code was entirely one-sided, all knowledge of natural phenomena being excluded. It was often said, he urged, that it was ridiculous to teach "ologies" before the children could read and write thoroughly. But, in the first place, it wag a misnomer to call the lessons he proposed "ologies"; secondly, it should be remembered that, when children were learning to read, they had to read something, and the question was what that something was to be. He wished for nothing difficult or abstruse, nothing beyond the range of the children's minds and daily experience. "In mechanics, the simple forces might be explained to them—why carts were put on wheels, how levers and pulleys acted, the use of the screw and wedge; then the nature and relative distances of the principal heavenly bodies, the primary facts relating to air and water in agricultural districts, the character of the soil, the reason for the rotation of crops, the origin and principal qualities of such substances as chalk, coal, iron, copper, etc.; the succession of the seasons, the flow of rivers, the growth of plants; the fundamental rules of health, the necessity for ventilation and cleanliness, and, last^ not least, the need for industry, frugality, and economy. Explanations of these simple and every-day things would be most interesting and useful to the children. So far from cramming and confusing them, you would introduce light and order into their minds, and give them an interest in their lessons, which, under the present system, they rarely felt."
Ancient Uses of Cork.—A writer in the "Pharmaceutical Journal" has collected a large amount of interesting information on the subject of the cork-tree and its bark, and the uses of the latter in both ancient and modem times. The tree, and the application of its bark to useful purposes, was well known to the Egyptians, Greeks, and Romans. The former used to construct their coffins of this material. Theophrastus, the Greek philosopher, who wrote on botany, etc., four centuries b. c., mentions this tree among the oaks, under the name of phellus, and says that it has a thick, fleshy bark, which must be stripped off every three years to prevent it from perishing. He adds that it was so light as never to sink in water, and on that account might be used for many purposes. Pliny describes the tree under the name of suber, and relates everything said by Theophrastus of phellus. From his account we learn that the Roman fishermen used it as floats to their nets and fishing-tackle, and as buoys to their anchors. The use of these buoys in saving life appears to have been well known to the ancients, for Lucian ("Epist. 1," 17) mentions that two men, one of whom had fallen into the sea, and another who jumped after to afford him assistance, were saved by means of an anchor-buoy. The use of this substance in assisting swimmers was not unknown to the Romans. By Plutarchus, in his "Vita Camilli," we are told that, when the imperial city was besieged by the Gauls, Camillus sent a Roman to the Capitol, who, to avoid the enemy, swam the Tiber with corks under him, his clothes being bound upon his head, and was fortunate enough to succeed in the attempt. The use of cork for stoppers was not entirely unknown to the Romans, and instances of its being thus employed may be seen in Cato's "De Re Rustica," cap. exx.; but its application to this purpose seems not to have been very common, or cork stoppers would have been oftener mentioned by authors who have written on agriculture and cookery, and also in the works of ancient poets. The convivial customs of those days had no connection with the bottle, glass bottles being of a much later invention. Instead of having dozens of sparkling champagne or hock, to be liberated from the bottle by the corkscrew, at their feasts, the guests filled their drinking-cups of gold, silver, crystal, or beech-wood from a two handled amphora, a kind of earthenware pitcher in which their choice wines used to be kept. The mouths of these vessels were stopped with wood, and covered with a mastic, composed of pitch, chalk, and oil, to prevent air spoiling the wine or evaporation taking place. Columella, who wrote one of the earliest works on agriculture, gives directions for preparing this cement. Pliny, in describing the cork-tree, says it is smaller than the oak, and its acorns of the very worst quality. He tells us the cork-tree did not grow throughout Italy, and in no part whatever of Gaul. At the present day it is abundant in France, and Fee states that the acorns of Quercus suber are of an agreeable flavor, and the hams of Bayonne are said to owe their high reputation from the pigs having fed on the acorns of the cork-tree. Some ancient authors speak of the cork-tree as the female of the holm-oak (Quercus ilex), and in countries where the holm does not grow, they used to substitute the wood of the cork tree.
Traditional Origin of Social Distinctions.—In the latter part of the fourteenth century social distinctions became the subject of theological controversy in England—the Lollards, a religious association including large numbers of the common people, maintaining the natural equality of man; while the Roman Catholic preachers, on the other hand, encouraged the belief that the division of society into distinct classes was a permanent judgment of God, the origin of which, according to Alexander Barclay, a poetical writer in the reign of Henry VII., they thus accounted for: "One day, while Adam was absent occupied with his agricultural labors, Eve sat at home on their threshold with all her children about her, when suddenly she became aware of the approach of the Creator, and ashamed of the great number of them, and fearful that her productiveness might be misinterpreted, she hurriedly concealed those which were the least well-favored; 'some of them she placed under hay, some under straw and chaff, some in the chimney, and some in a tub of draff; but such as were fair and well made she wisely and cunningly kept with her.' God told her that he had come to see her children that he might promote them in their different degrees, upon which she presented them in the order of their birth. God then ordained the eldest to be an emperor, the second to be a king, and the third a duke to guide an army; of the rest he made earls, lords, barons, squires, knights, and hardy champions; some he appointed to be 'judges, mayors, and governors, merchants, sheriffs and protectors, aldermen and burgesses.' While all this was going on. Eve began to think of her other children, and unwilling that they should lose their share of honors, she now produced them from their hiding-places. They appeared, with their hair rough and powdered with chaff, some full of straws, and some covered with cobwebs and dust, 'that anybody might be frightened at the sight of them.' They were black with dirt, ill-favored in countenance, and misshapen in stature, and God did not conceal his disgust. 'None,' he said, 'can make a vessel of silver out of an earthen pitcher or goodly silk out of a goat's fleece, or a bright sword of a cow's tail neither will I, though I can, make a noble gentleman out of a vile villain. You shall all be plowmen and tillers of the ground, to keep oxen and hogs, to dig and delve, and hedge and dike, and in this wise shall ye live in endless servitude. Even the townsmen shall laugh you to scorn; yet some of you shall be allowed to dwell in cities, and shall be admitted to such occupations as those of makers of puddings, butchers, cobblers, tinkers, costard-mongers, hostlers, or daubers.'" Such, the teller of the story informs us, was gravely taught as the beginning of servile labor.
Experiments in Punishment.—The present convict system of England is an outgrowth of the transportation system, which it has supplanted. It has grown up by successive alterations and improvements, made in accordance with varying circumstances and demands; and, to understand it fully, it is necessary to know something of the various experiments which have from time to time been tried with different methods of punishment. But, without going into this part of the subject, we give below the conclusions of a writer in the "Nineteenth Century" regarding the principles which experience seems to have established. They are: "1. That a well-devised system of secondary punishment should provide for subjecting those sentenced to it to a uniform course of penal deterrent discipline. 2. That every means possible should be adopted for developing and working on the higher feelings of the prisoners directly by moral, religious, and secular instruction, and indirectly by insuring industry, good conduct, and discipline, through appealing to the hope of advantage or reward, as well as by the fear of punishment. 3. That, with a view to deterrence as well as reformation, it is desirable that the first part of every sentence should be undergone on the separate system, as developed at Pentonville. 4. That, before discharging the convict to a full or modified degree of liberty, he should be subjected to further training, in which he should bo associated under supervision, while at labor, but separated at all other times. 5. That properly constructed prison-buildings, providing among other things for this separation, are all important requisites for the success of the system. 6. That employment should be provided, and industry enforced or encouraged for all. 7. That care should be taken to select and train a good staff of skilled and responsible officials to supervise and carry on the work of the convict establishments, and means adopted to prevent their work being hindered or defeated by the prisoners being brought into close contact, on works or otherwise, with free men who were under no such responsibilities. 8. That those who on discharge are disposed to follow honest courses should be guided and assisted in their endeavors, and that a careful watch should be kept over all till they have reestablished their character."
Anthropometric Observation.—The report of the Anthropometric Committee of the British Association showed that considerable progress was made during the past year in the matter of collecting valuable statistical information. Returns had been obtained, giving the birthplace, origin, and sex, age, height and weight, strength of arm, and eyesight, of pupils at sundry public schools, London policemen and letter-sorters, workmen, rifle volunteers, soldiers, and criminals. By this, means the committee were put in possession of nearly 12,000 original observations on the main question of weight and height in relation to age, in addition to 50,000 already collected. The committee submitted a series of tables made up from the information contained in the returns. From these it was shown that the London letter-sorters were the lowest in height, the average heights between the ages of twenty and thirty-five being 64 to 67·1 inches. The letter-sorters were also at the bottom of the weight table, their average weights in pounds being 122·5 to 139·9. The metropolitan police were at the head of both lists: height 69·2 to 71·5 inches and weight 122·5 to 182·7 pounds. Other tables were given, showing that the average height and weight vary with the social position and occupation of the people, and that to obtain the typical proportions of the British race it would ha necessary to measure a certain number of individuals of each class. Taking the census of 1871, they find that a model community—that is, a community which would exhibit the typical proportions of the British race—must consist of 14·82 per cent, of the non-laboring class, 47·46 per cent, of the laboring class, and 37·72 per cent, of the artisan and operative class. It is found that the full stature is reached in the professional class at twenty-one years, and in the artisan class between twenty-five and thirty years. The growth in weight does not cease with that of the stature, but continues slowly in both classes up to the thirtieth year.