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Popular Science Monthly/Volume 40/March 1892/Popular Miscellany

< Popular Science Monthly‎ | Volume 40‎ | March 1892


A Defense of Examinations.—Examinations are defended by W. H. Maxwell, in a paper which he read before the National Education Association at its meeting in 1890. To the question, "Is examination one of the means that occasion those mental activities which result in knowledge, power, and skill?" Mr. Maxwell gives an affirmative answer, saying: "Knowledge is not knowledge when it has been merely taken in. It is not knowledge until it has passed through the mind and come out again in words or actions of our own. Until this is done, we can not be sure even that we possess knowledge. Every thorough-going student has been at some time or other, when confronted with examination questions, amazed at his own ignorance of subjects with which he fondly imagined he was thoroughly familiar. There is probably no better test of a teacher's ability than his power to determine, during the giving of a lesson or after it has been given, whether it has been mastered by his pupils. And yet I have frequently seen teachers of great ability astonished at their pupils' ignorance of subjects which they (the teachers) thought had been completely mastered. In all these cases the examination test proves that the knowledge in question has not been assimilated, has not been converted into faculty. The very act of reproducing knowledge in the pupil's own words or acts is one of the best means of converting it into faculty; but it is not the only means. The process is not complete when isolated facts, nor even when divisions of a subject, have passed through the mind and been reproduced. All this is necessary, but it is not enough. It is but a means to an end, and the end is the comprehension of a subject as a whole, and the comprehension of the relations of the various parts to one another and to the whole. . . . Nor is even this all. The process of learning is not complete till the pupil can apply his knowledge in some practical way. . . . Examination consists not merely in reproducing knowledge imparted or acquired, but in making practical application of knowledge, in testing power and skill. And hence on this ground also—the ground of practical application as well as that of reproduction—examination, seeing that it is not only a test of application and reproduction, but an exercise in application and a means of the development of power and skill, must be regarded as an element of teaching what is good."


Climate and Health.—The modifying effects of differences in age deserve more attention than they have received in the discussion of the influence of climate upon health. The question is a practical one, and admits, according to the Lancet, of some fairly definite rules and principles. In general, children respond more readily to change than older persons. They commonly do well at the seaside; they often benefit signally by a sea-voyage, and do not suffer severely from the discomforts attending one. They suffer more than grown people from the depressing influences of city life; and, in a large proportion of cases, they are not specially benefited by the climate of high altitudes. The explanation of the love of children for the sea is that they are benefited by it, because they are commonly in a condition to bear stimulation, not having used-up nervous systems. They are attracted by the sea and its products, and by the amusements natural to the seaside; and some of their most common ailments are among the affections most amenable to sea influences. The advantages of mountain air to them are not so conspicuous, but much has yet to be learned on this subject before it can be discussed with full intelligence. Elderly people in general do well with equability and moderate warmth, bear cold badly, and are most benefited by abundant sunshine. High altitudes are rarely suitable to them, and often injurious; and they do best in level places, where there is abundant shelter. They may or may not benefit by the seaside or a sea-voyage, but these measures can not be recommended with the same confidence as to children. In nothing is the superior recuperative power of youth over age more apparent than in the greater readiness and certainty of its response to change of climate. We can confidently recommend to the young measures which we suggest dubiously to the old. In fact, change is rarely at fault in the earlier years of life, whereas it is often a doubtful and sometimes a hazardous experiment for the aged. In the case of the old, we need to have solid reasons and tolerably definite prospects before we induce them to give up the comforts and safety of home for the uncertainties of travel.


The United States Life-saving Service.—Systematic methods for the preservation of life from shipwreck were not adopted till very late in history. According to Mr. Horace L. Piper, of our Life-saving Service, the eighteenth century was "well in its twilight" before any organized effort, and that private, was made for this purpose. The first life-boat was not invented till after our independence was achieved, and George Washington had been two years President when the first serious steps in that direction were taken in England. The United States was abreast of other countries in this work. The Humane Society, organized in Massachusetts in 1786, devoted itself to it in 1789. The Life-saving Service of the United States was begun in 1848, was made more effective in 1871, and was organized into a separate bureau in 1878. For its purposes, the coasts of the Atlantic, the Gulf of Mexico, the Great Lakes, and the Pacific (excepting Alaska), comprising more than ten thousand miles, are divided into twelve life-saving districts, designated by number, beginning with Maine on the Atlantic and ending with Washington on the Pacific. Each district is in charge of a superintendent chosen for his knowledge of the subject, business capacity, and executive ability. The districts are subdivided into stations, known by the names of their localities, and situated with regard to the special dangers of the coast. They are of two kinds: complete life-saving stations, and houses of refuge. In all there are about two hundred and forty stations of both kinds, but some of them are not yet fully completed and manned. A majority of them are on the Atlantic coast; ten on the shores of Maine and New Hampshire; six in Massachusetts, where the Humane Society provides whatever other service is needed; thirty-nine on Long Island; forty in New Jersey; seventeen between Cape Henlopen and Cape Charles; twenty-three between Cape Henry and Cape Hatteras; one station and ten houses of refuge in Florida; eight on the Gulf of Mexico; fortynine on the Lakes; and twelve on the Pacific coast. Every station is in charge of an oflicer who is really the captain of the crew, but whose technical designation of keeper is a survival from the time when only one person was constantly employed and depended on volunteers for help. The crews are technically known as surfmen, and are selected by the keeper from the best men in the neighborhood. The crews are under the control of the keepers, and above these are the district superintendent, who visits the stations quarterly; the assistant inspector, who makes monthly rounds; and the general inspector, who reports periodically to headquarters in Washington. The statements of the operations of the service show that it has been very effective in saving life and property. The entire loss of lives on all the coasts of the United States under the present system since 18 VI has been only thirty-eight in excess of the loss on the Long Island and New Jersey coasts alone during the preceding twenty years. This efficiency is largely due to the fact that politics has not yet intruded into the service, while the principle of choosing and keeping the best men for their work has been steadfastly adhered to.


Organic Variation a Chemical Problem.—The laws of chemism are applied by Prof. A. E. Dolbear to explain the phenomena of protoplasmic growth and change. Since the discovery of the mechanical equivalent of heat there has been no alternative but to suppose those phenomena to be due to motion. Having shown that such motions of matter as constitute sound, heat, magnetism, and the rest, all produce fields external to themselves, and that within such fields other bodies are brought into similar states of position or of motion or both, the author would apply the same principle to protoplasm and cell structure. "Imagine a cell with any degree of complexity, surrounded by material such as it is itself composed of, and what should one look for to take place if not that the same kind of a structure should be reproduced? When this happens, we say growth has taken place, and it is attributed to life. As the new cell is similar to the old one that furnished the specific conditions for its development, we say it has inherited its form and functions. The bearings of this upon the fundamental problems of biology are apparent. If the foregoing be true, heredity is explained as much as inductive magnetism is, and is no more mysterious. . . . Suppose that in such a complex molecule as protoplasm a single atom of a different substance should accidentally become imbedded, either as a constituent or not, it would bring its field along with it necessarily, and the resultant field of the whole would be modified. It could not be what it would be in the absence of this new constituent, and consequently the reaction upon other matter in its neighborhood would be different, and the next organic molecule formed would need to be a little differently organized. Mechanical conditions would necessitate it. Again, if energy, radiant or conducted, should act for a short time upon one part of a molecule, it might easily bring about an exchange of positions among some of the less stable constituents without other disturbance, and this too would result in a change of the configuration of the field and the direction of growth. Every change in the collocation and motions among molecules exhibits itself in changed properties. Such conditions might properly be spoken of as changes in the environment, but it is molecular environment, and the difference between this idea and that heretofore common is, that the molecule produces an environment of its own—the space beyond its own geometric boundary, in which it is competent to act upon other bodies and compel other bodies to conform in a greater or less degree to it. More than that, a new constituent in a nearly saturated molecule could not have as firm a grip upon the structure as the older constituents could have, although it might so modify things while present as to organize other molecules in like manner, but slight changes in the neighborhood might slough off the new acquisition in a subsequent generation, so there might be a return to the form and qualities of the ancestry—that is, reversion to a former type would also be a mechanical consequence. Thus growth, heredity, variation, and reversion may be considered as the consequence of atoms vibrating in harmonic orders, each producing its own field in the universal ether, and each group of atoms constituting a molecule, large or small, having a field which is the resultant of all the fields of its constituents. All of them are molecular properties as much as any one of them can be, and growth has been believed for a long time to be a property of inorganic molecules. The cause of variation is therefore molecular as truly as isomerism is a different collocation of atoms. It is a chemical problem."


Snake-myths.—A great deal of nonsense has been published, and a great deal more is believed, about snakes. Some most thrilling stories turn upon a power which serpents are credited with of fascinating their victims. This appears to be a superstition. According to Mr. Vincent Richards, mice, birds, dogs, guinea-pigs, and other small animals, introduced into a rattlesnake's cage, show little fear, even at first, and afterward none whatever. Smaller birds, after fluttering about till they are tired, end by becoming amusingly familiar with the snakes. Mr. Richards put two rats into a cage containing forty cobras. At the outset the rats' appetites were considerably affected, and they were evidently alarmed. In a short time, however, they recovered their spirits, and caused considerable commotion among the cobras by running all over their heads and bodies. The snakes resented this familiarity by darting at each other and at imaginary foes. The rats lived and partook of food in the cage for ten or twelve days, when, one after another, they were found dead—"victims, no doubt, of misplaced confidence." It is still a matter of debate whether snakes are proof against their own poison. The remedies advised for snakebite are of doubtful validity. Because a man recovers after being bitten by a snake, and dosed with opium, mercury, ammonia, or what not, we must not jump to the conclusion that the treatment has effected a cure. A snake may bite without poisoning. Biting, though in appearance simple enough, consists really of a series of complex movements, following rapidly one upon another in ordered sequence, should any of which be inadequately performed, the victim may not be properly poisoned. Ammonia, alcohol, and making the patient move about, are worse than useless; for they increase the activity of the circulation, and thereby promote the absorption of the poison. Even permanganate of potash is of no effect unless it is administered within four minutes. Researches into the nature of the poison have shown that it resides in some proteid, and that there are three toxic elements—globulin, serum albumen, and acid albumen—but wherein the quality consists that gives to these substances, usually so harmless, their poisonous power, is as much in the dark as ever.


The Gems of the Ancients.—The gems of the ancients, according to Prof. J. H. Middleton's book on the Engraved Gems of Classical Times, consisted chiefly of the varieties of quartz—including colorless rock crystal, amethyst, sard, carnelian, chalcedony, chrysoprase, plasma, jasper, onyx, and sardonyx. Among the non-silicious stones were chrysoberyl, topaz, emerald, garnets, peridote, turquoise, opal, and lapis lazuli. The translucent stones are preferred, for artistic purposes, to the transparent ones. They admit the light, but not the forms of objects, and better reveal the charms of fine and noble workmanship. Many "gems" have been wrought or reproduced in paste and glass. Paste was a hard glass colored by various metallic oxides, such as those of manganese, iron, copper, and cobalt. Sometimes a piece of paste was treated by the gem-engraver just as if it were a natural stone, and sculptured by the aid of the same tools; but inore generally the glass was melted and pressed into a mold. Such a mold had been taken from an engraved gem by a pellet of clay which was afterward hardened by fire. Paste gems arc often beautiful in color and design, though the material lacks something of the optical properties which distinguish many of the true natural stones. The tools and processes employed in ancient times in engraving gems were virtually the same as those in use to day—drills, wire saws, and files, re-enforced with emery, and gravers of diamond, sapphire, or rock-crystal.


Courtship in Torres Strait.—The people living on the islands of Torres Strait are divided by Prof. Arthur C. Haddon into the eastern and western tribes, and customs differ considerably among them. While the usual course in marriage is followed by the eastern tribe, in the western tribe the girls propose—or did, till "civilization" overtook them—marriage to the men. "It might be some time before a man had an offer; but should he be a fine dancer, with goodly calves, and dance with sprightliness and energy at the festive dances, he would not lack admirers. Should there still be a reticence on the part of his female acquaintances, the young man might win the heart of a girl by robbing a man of his head. Our adventurous youth could join in some foray; it mattered not to him what was the equity of the quarrel, or whether there was any enmity at all between his people and the attacked. So long as he killed some one—man, woman, or child—and brought the head back, it was not of much consequence to him whose head it was. . . . The girl's heart being won by prowess, dancing skill, or fine appearance, she would plait a strong armlet, tiapururu; this she intrusted to a mutual friend, preferably the chosen one's sister. On the first suitable opportunity the sister said to her brother, 'Brother, I have some good news for you. A woman likes you.' On hearing her name, and after some conversation, if he was willing to go on with the affair, he told his sister to ask the girl to keep some appointment with him in the bush. When the message was delivered, the enamored damsel informed her parent that she was going into the woods to get some wood or food, or made some such excuse. In due course the couple met, sat down and talked, the proposal being made with perfect decorum. The following conversation is given in the actual words used by my informant, Maine, the chief of Tud. Opening the conversation, the man said, 'You like me proper?' 'Yes,' she replied, 'I like you proper with my heart inside. Eye along my heart see you—you my man.' Unwilling to give himself away rashly, he asked, 'How you like me?' 'I like your fine legs, you got fine body—your skin good—I like you altogether,' replied the girl. After matters had proceeded satisfactorily, the girl, anxious to clinch the matter, asked when they were to be married. The man said, 'To-morrow, if you like.' They both went home and told their respective relatives. Then the girl's people fought the man's folk, 'for girl more big' (i. e., of more consequence) 'than boy'; but the fighting was not of a serious character, it being part of the programme of a marriage. 'Swapping' sisters in matrimony was a convenient way of saving expense in the way of wedding gifts, for one girl operated as a set-off to the other."


Valne of Photography.—The name of impressionists has been given to a school of painters who, abandoning all consideration of the arrangements and mechanism of previous workers, have consulted only their im. pressions of natural scenes, and have painted to those impressions. "With one point of sight and one subject of supreme interest they have aimed to seize above all the action and first impression of that subject." The naturalistic school trust rather to a study of Nature, and make its truthful representation and perfect expression the criterion of their art. Mr. George Davison sees no reason why photography should not be used to express our impressions of natural scenes as well as any other black-and-white method. Worked under the same conditions as the eye, or under conditions as nearly approximate as possible, nothing, he says, gives so truthful a record in drawing as photography, and nothing, when the proper means are used and the requisite knowledge is possessed by the photographer, gives so delicately correct a relation of tones. It is to the proper use of the proper means at their disposal that photographers need stimulating. The most important of these means are such as are directed to securing the proper light effect and relations of light values, and those which give the focusing and relative interests of the subject. Some of the simplest facts of light are overlooked by photographers, who have been governed by untrue and misleading conventions and dogmas concerning gradation and brilliancy. Instead of deep black prints usually in favor among them, it is of first-rate importance in landscape pictures to keep the shadows light. To repeat the impression of outdoor light the whole picture must be luminous, and not heavy and dark, as is the effect of the ordinary style. Further, the shadows when the sun shines are lighter than when he is obscured. The printing medium employed is an important consideration. Mr. Davison finds excellent qualities in the newest extra rough-surfaced papers. Photography is good under suitable conditions of light for representing transient action and effects. Photography has preeminently more of painting qualities than any other monochrome process. It is not specially limited to nor compelled to emphasize facts of form. It gives form by means of tone against tone—the best means of rendering it—and its truth of form is unlimited. It is equal to any other black-and-white process. In nothing more than closed forms is the delicacy of its tonal discriminations shown. The quality of naturalness will tell in the long run. Men will weary of emphasis, and graphic artists will leave past history, archaeology, and fiction to literature or scientific drawing.


A Voodoo Initiation.—A paper was communicated to the International Folk-lore Congress in London by Miss Owen on Voodoo Magic, to the mysteries of which she alone among white women had been initiated. The ceremony of initiation began with a walk at midnight, barefooted and bareheaded, to a fallow field. The author had to walk backward to the field, and when there, to pull up, with her hand behind her, a weed by the roots. She was then bidden to run home and throw the weed under her bed, to be left there till sunrise. Next, the weed had to be stripped of its leaves and made into a little packet, to be worn under the right arm for nine days. At the end of this time the leaves of the packet had to be scattered to the four winds, a few being thrown at a time over the right shoulder as the novice turned round and round, so that they might fall north, south, east, and west. When this was done the novice was ready for instruction. She learned that the preeminently lucky number which, when woven into incantations, was irresistible, was four times four times four; while ten was the unlucky number. After this a knowledge of the value of certain vegetable remedies and poisons had to be acquired. Charms were divided into four degrees. The first were good charms, the hardest to work, because good is always more difficult to practice than evil; the second were bad charms and fetiches made in the name of the devil; the third had special reference to bodily ailments; and the fourth related to what were called "commanded things," such as earth and pieces of stick. After each lesson both pupil and teacher had to get drunk, either by drinking whisky or by swallowing tobacco-smoke. To be thoroughly equipped the novitiate must possess a conjuring-stone—a stone black, kidney-shaped, and very rare. These stones were supposed to operate most rapidly when the moon was full or just beginning to wane. At other times, if the stones were not efficacious enough, their potency could be stimulated by a libation of whisky.


Cremation in Japan.—We are indebted to a correspondent of the London Spectator for the following interesting account of this method of disposing of the dead in Meguro, Tokeigo. It appears that cremation is the general custom among the "Monto sect of the Buddhists," a highly enlightened branch of Japanese Buddhism, which holds to the immortality of the soul as one of its leading tenets. "The building is of plaster, with an earthen floor, with stone supports for bodies. The chimneys are wide, and are carried to a considerable height, and there is no escape of disagreeable effluvium over the neighborhood. The bodies in the ordinary wooden chests which are used for burial are placed upon piles of fagots at 8 p. m., and are totally consumed by 6 a. m. The relations are admitted early in the morning, and the ashes are collected and placed in urns. The scale of charges is 3s. 6d., 7s. 6d., 15s., and 20s., the process in each case being the same, the only difference being that the highest charge insures a solitary chamber, while for the lowest the corpse may be consumed in company with five others, each, of course, occupying a separate stone platform."


Chinese Cookery.—It appears, from the Pall Mall Budget, that the great number of strange dishes spoken of in books of travel are seen only at official banquets, and do not constitute the meals even of the wealthy Chinese. These public dinners are usually given in restaurants, which are built two or three stories high, the kitchen and public rooms being on the first floor, the private rooms above. A correspondent of the Journal des Débats gives the following as the bill of fare at a banquet given by a French official of the Chinese Government to Chen Pao-Chen, the Viceroy of the Two Kiangs: "Four large 'classical' or stock dishes—swallows'-nest soup with pigeons' eggs, sharks' fins with crabs, trepang (bâche de mer) with wild duck, duck with cabbage. Dishes served in cups placed before each guest—swallows' nests, sharks' fins, wild cherries, vegetables, mushrooms with ducks' feet, quails, pigeons in slices, dish of sundries. Four medium-sized dishes—ham and honey, pea-soup, vegetables, trepang. Four large dessert dishes—pea-cheese with bamboo roots, bamboo roots, chicken, shell-fish; four dishes of dried fruits as ornaments, four kinds of dry fruits, four kinds of fruits in sirup, four kinds of fresh fruit; four dishes of hors d'œuvre (two varieties in each dish)—ham and chicken, fish and gizzard, tripe and vermicelli, duck and pork chops. Dishes set before each guest—almonds and watermelon pips, pears and oranges. Sweet and salt dishes served in cups set before each guest—two kinds of salted cakes, hambroth, a broth composed of pork, chicken, and crab boiled down, two sweet cakes, a cup of lotus fruit, a cup of almond milk. Roast and boiled meats—sucking pig, roast duck, boiled chicken, boiled pork. Entremets—a dish of cakes with broth, slices of pheasants. Last service—mutton broth, almond jelly, white cabbage, pork and broth, bowls of rice, cups of green tea." Notwithstanding this elaborate "bill of fare," the Chinese are generally an abstemious people. A coolie will subsist upon eight shillings a month, and live comfortably upon twice that sum. Boiled rice is the staple article of food. In the north of China wheat and canary seed, boiled and made into small rolls, are much used. Small cakes made of boiled wheat, together with a little fish or some vegetables, constitute an excellent dinner for a Chinaman. Some light refreshment is frequently taken between meals by the well-to-do Chinaman—"the kuo tsâ leading up to the morning, the kuo tsong to the midday, and the tien chen to the evening meal, while the chian ya and the kuo yia are partaken of during the night by those who can not get to sleep."


A Defense of Opium-smoking.—That there is no cause without its advocate is evident from the fact that Consul Gardner, in a trade report for the past year, plausibly defends the practice of opium-smoking. We gather the following from the Pall Mall Budget: About 12,000,000 pounds of opium are yearly consumed in China. The smokers are of three classes—occasional smokers, habitual moderate smokers, and excessive habitual smokers. When a Chinaman is said to smoke opium, the recognized meaning is that he belongs to the third class, just as with us when we say that a man "drinks," excessive drinking is understood. In smoking, only part of the drug is consumed; the ash when re-prepared yields fifty per cent of opium. This accounts for the fact that the saloon-keepers sell opium at what appears to be cost price; the ash yields the profit and pays for light, house-rent, and attendance. It is estimated that the immoderate smoker consumes not over four pounds a year, and the average annual consumption of all classes is half a pound. If, as this implies, half the adult population smoke, and opium-smoking is the evil it is represented to be, why are there not visible inherited ill effects? Consul Gardner, in reply, says: "The length of the intestines in man shows that a due admixture of animal and vegetable food is the diet best suited to him. In China the population lives almost entirely on vegetables. Opium-smoking slows the processes of digestion, and, in fact, has the same effect as long intestines, and consequently is highly beneficial." Again, the Chinese live in low, undrained grounds, and are consequently liable to attacks of fever and ague. Under similar circumstances the lowlanders of Lincolnshire took to laudanum; the Chinese take opium in another form. Residents in China are struck with the comparative freedom of the people from pulmonary diseases. "That this immunity is not due to chmatic influences is clearly proved by the fact that Europeans and Americans are not more free from the scourge in China than they are in their own countries." Morphia is an anæsthetic, and rarefied as smoke probably an antiseptic. "In this form it would tend to arrest the suppuration of the lungs that takes place in consumption."


Oscillations of Alpine Glaciers.—About thirty years ago, according to Herr von E. Richter, the glaciers of the Alps began a precipitate retreat. In 1870 the ti-aveler often found a stone-strewn plain or an undulating slope of polibhed rock where ten years before he had scrambled over crevassed ice. About five years later, a slight, transitory forward movement was perceptible, while now the indications of an advance are becoming more marked. Similar changes, at earlier dates, are on record, and their history has been studied by Prof. Forel, Ilerr von Richter, and others. The historical period of the oscillations of the glaciers extends back about three centuries, while prior to this the notices are too sparse and vague to be of any real use. In this period eight marked epochs of glacier growth are on record. The first began in 1592, and the last, excluding the slight one of 1875, in 1835. Each was followed by a period of diminution. The intervals between the epochs vary from twenty to forty-seven years. The observations are not numerous enough to give trustworthy indication of a law, but are supposed to hint at one. The changes are connected with climatic variations, but effects are produced more quickly than is generally supposed. In the present century the curves representing the oscillations of the glacier and those of the annual temperature nearly correspond. Some traditions assert that in the middle ages the glaciers had almost melted away from many parts of the Alps, and passes were then crossed by women and children which are now left to experienced mountaineers. Their evidence relates to the cultivation of vines, cereals, etc., in localities where they are no longer grown, and to the former use of passes which are now practically closed. To the former evidence, as Herr Richter shows, little weight can be given. Man and Nature are in constant conflict in the Alps, and the position of the frontier line between their territories is determined by the convenience of the former. If a particular form of cultivation ceases to be remunerative all the advanced posts are abandoned. Herr Richter, likewise, does not give much force to evidence based on the disuse of passes. This is more than likely to have been brought about by the discovery of better ways or the making of new roads. In short, says the Saturday Review, under this author's treatment, "the traditions, not the glaciers, become unsubstantial, and the warm epoch in the mediæval history of the Alps goes the way of many other legends."


Origin of the Colors of Flowers.—Any one, says Mr. E. Williams Hervey, in Garden and Forest, can solve the problem as to the primitive color of flowers by a study of the native wild plants growing by the roadside or in the fields and woods. Two methods, he says, are employed by Nature in the development of colors, one of which he calls the imperfect or foliar development, and the other the normal floral process. In the former, the colors are apparently evolved directly from the green chlorophyl, as the reds, purples, and yellows of autumn leaves; for from some green-colored flowers a rather limited number of dull reds, purples, and yellows are produced. The reds and reddish purples are, however, rare, and appear mostly on the scales of involucres, where they are common, on the spathes of several of the Aracæe, in Salicornia of the salt marshes, which turns red in the fall, and in the castor oil plant of gardens, which turns a reddish purple in all its parts. The author does not find a satisfactory example of yellow evolved directly from green among our native plants, and doubts if any pure yellow ever immediately succeeds green. But there are some greenish-yellow flowers. For illustration of the normal floral method of development by which he believes all the bright, attractive hues of the floral world are produced, the author takes up the Spiranthes gracilis, or ladies-tresses, an orchid which grows in all our fields, having small white flowers spirally disposed at the summit of the scape. The lip is green, fringed around the edges with white, and the other petals are wholly white. "A small section of the petals, placed under the magnifying glass, appears colorless and transparent, while the delicate network of the tissue glistens like crystal; yet this colorless tissue, in a mass, reflects white. In the same manner a single leaf-like bract of Monotropa uniflora, severed from the stem, appears colorless; but two or more placed together, making a greater thickness, reflect a decided white color." Attention is called to the fact that in Spiranthes the white color directly succeeds the dark rich green of the lip. The author then endeavors to demonstrate that the universal law of progression in color, as regards the floral structure, is first from green to white; "or, differently stated, Nature, before she begins to paint the more rich and delicate tissue of the petals, by some secret chemical process completely eliminates the chlorophyl and prepares a perfectly pure and white canvas upon which to essay higher flights of fancy." Twenty-eight wild and garden flowers are cited as illustrating this principle in the development of their colors, and numerous inconspicuous or weed-like plants in the coloring of their sepals; while the hues of flowers of other colors are thus produced by transition through white, "without a single exception every flower that came to hand of a white color was developed directly from green, without any intervening color."


Canaries.—A correspondent of the London Spectator writes chattily of his pet canaries, and seems to show that they are very human in their reason and unreason. During some intensely hot weather, when the hen was sitting, she drooped, and it seemed as if she might not be able to hatch her eggs. The cock, however, showed himself an excellent nurse. After bathing in fresh cold water, he went every morning to the edge of the nest and allowed the hen to refresh herself by burying her head in his breast. A green and yellow canary hung side by side, and were treated exactly alike. One day three dandelion blossoms were given to the green bird and two to the yellow one. The latter showed his anger at the proceeding by "flying about his cage, singing in a shrill voice." But when one of the three flowers was taken away, both birds seemed quietly to enjoy their feast.


Utilizing the Less-known Metals.—In closing his presidential address before the Chemical Section of the British Association, Prof. Roberts-Austen spoke of the great importance of extending the use of the less-known metals. He supposed that in the immediate future there would be a rapid increase in the number of metallurgical processes that depend on reactions which are set up by submitting chemical systems to electrical stress. Attention is at present concentrated on the production of aluminum. Sodium, also, is of growing importance, both for cheapening the production of aluminum, and as a powerful weapon of research. The manufacture of magnesium, which was a curiosity in 1849, has become an important industry. We may confidently expect to see barium and calcium produced on a large scale as soon as their utility has been demonstrated by research. Minerals containing molybdenum are not rare; and the metal could probably be produced as cheaply as tin if a use were to be found for it. The quantities of vanadium and thallium which are available are also considerable; but we as yet know little of the action when alloyed of those metals which are in daily use. The field for investigation is vast, for it must be remembered that valuable qualities may be conferred on a mass of metal by a very small quantity of another element. The useful qualities imparted to platinum by iridium are well known. A small quantity of tellurium obliterates the crystalline structure of bismuth; but we have lost an ancient art, which enabled brittle antimony to be cast into useful vessels. Two tenths per cent of chromium increases the strength of gold enormously, while the same amount of bismuth reduces the tenacity to a very low point. Chromium, cobalt, tungsten, titanium, cadmium, zirconium, and lithium are already well known in the arts, and the valuable properties which metallic chromium and tungsten confer upon steel are beginning to be generally recognized.