ELEPHANTS MOVING TIMBER AT MOULMEIN, BRITISH BURMAH.
ELEPHANTS MOVING TIMBER AT MOULMEIN, BRITISH BURMAH.
It is reported that a comparison of the relative strength of yellow and Norway pine was made at Dayton, O., with the following results: The specimens were dressed exactly one inch square, and these were broken in a testing machine by placing them on bearings, one foot apart, with the weight in the center. The southern pine had been air seasoned for two years and upward, the Norway from a year to fifteen months. The weakest yellow pine broke at 763 pounds, the strongest at 1,102; average of eight specimens, 904 pounds. The weakest Norway broke at 501 pounds, the strongest at 790 pounds; average of ten specimens, 702 pounds, showing the yellow pine to be 28.7 per cent. stronger than Norway, and that a yellow pine sill 4x8 inches dimensions is equivalent to a Norway sill of 5½x8 inches, with the further advantage in favor of the yellow pine that it can be got much freer of knots and consequently stronger in comparison than these figures show, which are based on clear timber. Another test was made at a meeting of the Master Car Builders' Association, with the following results: Five pieces of each variety, one inch square and eleven inches between bearing points, were experimented upon, the pressure being applied in the center. The outcome showed strength of yellow pine at 500, 510, 500, 490, and 530 pounds breakage strain, or an average of 506; while Norway stood a strain of 620, 645, 730, 650, and 630 pounds or an average of 625 pounds. These experiments do not appear to throw much light on the question of relative strength.
"Our women in Germany," said the professor of a German university to me, a few days ago, "must by all means be acquainted with the different departments of housekeeping, and must interest themselves therein. Those who stand highest as well as those who stand lowest, from the wives and daughters of a Minister of State to the wives and daughters of the meanest peasant. The Princess-Royal attends to the skimming of the milk in her dairy." "I beg your pardon for interrupting you," I said, "but an American lady would think that quite out of her sphere; and if I were not convinced of your seriousness, I should imagine you were amusing me by a piece of fiction." "I do assure you," replied the professor, "that it is a well known fact that the Princess-Royal keeps cows and superintends personally the management of her dairy, and I have heard that the Queen of England does the same." "Please to instruct me further regarding the education of women in Germany," I said. "I am very much interested in that subject, as, from my own observations, I have seen that as a general thing the German ladies are well read, not only in the literature of their own country, but also in that of France and England." "Our women," he replied, "also speak French and English, especially French, and many of them are able to read the authors of those countries in the original." "This is the more surprising to me," I remarked, "as they seem to be much occupied with the cares of housekeeping, and I would like to know how they find time to learn foreign languages, and to read all the principal works of the poets and romance writers of three countries." "That," said the professor, "is a part of their education, and in order that you may understand in what manner German girls must utilize their time at school, I will give you a brief explanation of the system of education employed and of that knowledge which it is incumbent upon every German girl to possess, whatever be her position in life, and afterward of the different grades of education from that of the peasant girl to that of the lady of the highest position in the State. Every girl in Germany must learn to read and to write, to sew and to knit, to cook and to do general housework, and to acquire besides some general knowledge of grammar, geography, mathematics, and history. Beginning at the daughter of theBauer, or, as you say in America,farmer, the above mentioned knowledge, which is the starting point for the education of the other classes, is the limit of her education; and as it may be interesting to you, I will mention that when the daughters of the Bauer have learned thus much they quit school and labor in the field until they are married, when they leave aside the field work and enter upon the duties of the household and its immediate attachments, such as the dairy, the chicken yard, the gardens, etc.; and while the products of the field belong to their husbands, the garden stuffs, and the milk, eggs, butter, etc., become their own property, and from the profits of these, which they carry to the markets and sell, they provide their pantries with the necessary teas, sugar, coffee, etc., and themselves and their children with clothes.
"Between the peasant class and nobility there are many grades and classes varying more or less in the refinement of their manners as well as in the extent of their education, but as it would not be possible and is also unnecessary for our purpose to describe them all in particular, I prefer to include them all under the head of gentry, and for these a more ample education is provided. The daughters of the gentry must, in addition to the aforesaid rudiments of knowledge, have a very thorough education in history as well as in grammar, mathematics, and natural and physical geography.They must know French and English, and have an intelligent understanding of the literature of those countries, as well as of that of Germany. They must learn fine needle-work and the art of governing a house and of educating young children. They must also acquire a knowledge of good manners and an understanding of society. They must be able to receive company and do the honors of the house. In addition to this they will have an intelligent understanding of music and art. For all of these branches of knowledge there are schools provided, and according to the position or wealth of the parents, or the intelligence and application of the daughters, will vary the refinement and education of each. As, for instance, the education of a country squire's daughter will be superior to that of a wholesale merchant's daughter, and that of the wholesale merchant's daughter will be superior to that of the retail merchant's daughter. The daughter of a very wealthy banker will be educated above the daughters of the merchants; the daughter of a professor of the University above that of the daughters of a professor of the Gymnasium, and so on; and each will fill a position in life differing from that of the others, according to the respect in which the position of the parents is held.
"The same system of education which we have described for the daughters of the gentry will be incumbent on the daughters of the nobility, with the addition of a more finished and thorough education in regard to the manners and formalities which attach to their station of life, and these will also vary in kind and extent, according to the position of the persons concerned. A Duke's daughter, for instance, will be more accomplished than a Count's. But the difference will be more apparent than real; the actual knowledge of both will, as far as their education provides, be the same. In the society of the Court, the ladies will naturally acquire some knowledge of the affairs of State, which those in private life and a more retired existence will not care to learn. But in matters of art, in literature, in the general business of life, all German ladies are expected to be well informed and to be able to converse intelligently regarding them, while the special faculties of law, of medicine, of theology, of chemistry, etc., etc., are left to the higher ambition of their fathers and brothers, and they do not meddle with them. But, above all, as I remarked in the beginning, a German girl of whatever rank or condition must understand fully all the matters concerning ahousehold."
When the Professor had finished, I thanked him and expressed so much admiration at the system of education provided for the women of Germany, that he promised me at some future time a brief explanation of morals and manners in Germany, which I shall be most happy to present before the reader at the proper time.K.G.D.
The most ancient of such instruments is certainly the syringe. The Egyptians, says Herodotus (ii., 87), employed the latter in the embalming of common people, for filling the belly with oil of cedar, through injections madeper ano, without opening the body and extracting the intestines. Heron, in his "Pneumatics," describes an instrument of this kind, calledPyulgue, which was designed for sucking pus out of wounds.
The following apparatus, also described by Heron, is the first step that was taken toward the production of the pneumatic apparatus properly so called
"Construction of a cupping glass that sucks without the aid of fire."
LetΑΒΓ(Fig. 1) be a cupping glass (like that which is usually applied to the skin), divided by a partition,ΔΕ. Through the bottom let there be passed two tubes that slide one within the other by friction—ΖΗbeing the external andΘΚthe internal one. In these two tubes, external to the glass, there are two apertures,ΛΜ, that face each other. The extremities of the tubes situated within the apparatus should be open, and the external extremity ofΘΚshould be closed and provided with a key. Beneath the partition,ΔΕ, there is another cock,ΝΞ, like the one just described, save that the corresponding apertures are within the cupping-glass, and are in communication with an aperture in the partition,ΔΕ.
"Things being arranged thus, the keys of the cock are revolved in such a way that the apertures of the one at the bottom of the instrument are in a line with each other, while the cock above the partition remains closed, inasmuch as its apertures do not correspond. The chamber,ΔΓ, being full of air, if we apply the mouth to the orifices,ΛΜ, and suck out a portion of the air, and turn the key of the cock without removing the mouth from the tube, we shall be able to thus keep up a rarefaction of the air in the chamber,ΓΔ. The oftener we perform this operation, the more air we shall remove. Let us now apply the cupping-glass to the skin in the usual way, and open the cock,ΝΞ, by turning the key. A portion of the air contained inΑΔΕwill pass intoΓΔ, and we shall then see the skin, as well as the subjacent matters that pass through its interstices, that we call unexplored spaces, drawn into the space in which the air is rarefied."
As for the pressure fountain, this had reached perfection as long ago as the Alexandrine epoch. The following description of it is borrowed from the "Pneumatics:"
"To construct a hollow sphere, or any other vessel, in which, if a liquid be poured, the latter may be made to rise spontaneously with great force so as to empty the vessel, although such motion be contrary to nature."
"The construction is as follows: Let there be a sphere of a capacity of about six cotyles (about 2¾ pints) made of some metal tough enough to withstand the pressure of the air that is to be produced. Let us place this sphere,ΑΒ, upon any base whatever,Γ. Through an aperture in its upper part we introduce a tube which runs down to that part of the sphere which is diametrically opposite the aperture, but which leaves sufficient space there for the water to pass. This tube projects slightly above the sphere, to whose aperture it is soldered, and divides into two branches,ΗandΖ, to which are affixed two bent tubes,ΖΜΝΞandΗΘΚΛ, that communicate internally withΗandΖ. Finally, in these tubes,ΗΘΚΛandΖΜΝΞ, and in communication with them, there is adapted another tube,ΠΟ, from which issues at right angles a small tube,ΡΣ, that communicates with it and terminates atΣin a fine orifice.
If, taking the tube,ΡΣ, in hand, we revolve the tube,ΠΟ, the two apertures that face each other can no longer establish a communication, and the liquid that rises will no longer find an outlet. Then, through another aperture in the sphere, we insert another tube,ΤτΦ, whose lower orifice,Φ, is closed, but which has upon the side, toward the bottom, atΧ, a round hole to which is adapted a small valve of the sort called by the Romansassarium. Into the tube,τΦΤ, we insert another and closely fitting tube,ΨΩ. Let us now remove the tube,ΨΩ, and pour liquid into the tube,τΦΤ. This liquid will enter the cavity of the sphere, through the aperture,Χ. The valve will open in the interior, and the air will escape through the apertures in the tube,ΟΠ, of which we have already spoken, and which have been so arranged as to communicate with the tubes,ΗΘΚΛandΖΜΝΞ. When once the sphere is half full of liquid, we incline the small tube,ΡΣ, so as to shut off all communication between the corresponding apertures, and then push down the tube,ΨΩ, and drive into the interior of the sphere the air contained inΤτΦ. This requires some force, as the sphere itself is full of liquid and air, but the introduction is rendered possible through the compression of the air, which shrinks into the empty spaces that it contains within itself. Let us now take out the tube,ΨΩ, again so as to fill the tube,ΤτΦ, with air, and let us push down the tube,ΨΦ, again and force this air into the sphere. On repeating this operation several times in succession we shall finally have in the sphere a large quantity of compressed air. It is clear, in fact, that the air introduced by force cannot escape when the piston-rod is raised, since the valve, pressed by the internal air, remains closed. If then, replacing the tube,ΡΣ, in a vertical position, we set up a communication again between the corresponding apertures, the liquid will be driven to the exterior through the compressed air, and the latter will assume its normal volume again, and press in the liquid beneath it. If the quantity of compressed air is considerable, there will occur an expulsion, not only of the entire liquid, but also of the excess of air.
Fig. 1.—HERON'S CUPPING GLASS.
Fig. 1.—HERON'S CUPPING GLASS.
The valve of which I have spoken is constructed as follows (Fig. 2, 1bisand 1ter): Take two pieces of brass about one inch square, and about as thick as a carpenter's rule, and rub their surfaces against each other with emery, that is to say, polish them so that neither air nor liquid can pass between them. In the middle of one of the pieces bore a circular aperture about4/10an inch in diameter. Then fitting the two plates together by one of their edges, unite them by a hinge so that the polished surfaces shall coincide with each other. When this valve is to be made use of, the part containing the aperture is adapted to the aperture that is designed for the introduction of the liquid or air that is to be compressed. The pressure causes the other part of the valve (which moves easily on its hinge) to open and allow the liquid or air to enter the tight vessel, wherein it is afterward confined and presses against the unperforated part of the valve and thus closes the aperture through which the air entered."—A. de Rochas, in La Nature.
Fig. 2.—HERON'S FOUNTAIN.
Fig. 2.—HERON'S FOUNTAIN.
Professor Adolf Meyerhas been experimenting upon the relative digestibility of natural and artificial butter. The experiments were made on a man of 39, and a boy of 9 years. He found that there was but little difference, but in these individuals the natural butter seemed to be more easily digested. While natural butter was all digested, at least 98 per cent. of the artificial butter was also digested.—Chemiker Zeit.
An editorial comment inThe Medical Recordof April 14th, upon a paper by Dr. Hamilton, of Philadelphia, may serve as an apology for some remarks on a subject which ordinarily seems to possess scarcely more interest for practicing physicians than for "practical" laymen; both being wont to lay the finger of incredulity against the nose of scorn when they turn their deafest ears to the voice of the sanitarian. In the present very unsettled condition of professional opinion as to the diagnosis of typhoid fever—passably good authorities in India, on Western mountain peaks, and even nearer home, differing widely thereanent—I shall not attempt here to discuss its etiology, or to single out for reprobation any particular one of the several kinds of bacteria which have been respectively described as its exclusive cause. Suffice it merely to hint that there may be possible source of error in statistical arguments touching its relative frequency in town or country. But, waiving this, I am not aware that "professed sanitarians" have ascribed to "sewer-gas" alone such pre-eminence over other vehicles of filth or fungi as the article in question imputes. On the contrary, I believe that the majority of cases of enteric fever which have been traced accurately to their origin have been traced to other and more tangible contaminations of food or water. Nevertheless there is strong evidence, which has stood the test of much cross examination, that the so-called "filth diseases" deserve their name in this respect: that whatever be the specifictertium quidwhich determines their occurrence in the individual, filth-poisoning (i. e., the imbibition, through some channel, of the products of organic decomposition) is an essential factor in their genesis.
The first source of fallacy in the arguments referred to lies in the misinterpretation of the term "sewer gas," connecting it with sewers in particular instead of with sewage in general. Thus, I find it stated that typhoid is "more prevalent in the suburbs and surrounding country than in the cities subjected to the contamination of sewer gas;" that diphtheria and scarlatina occur most fatally "in the country, where sewer gas is wanting;" and that in Philadelphia the extension of the sewage system into the rural sections has diminished the sickness from fever. Now the facts on which most sanitarians lay great stress are, that unsewered rural districts are more exposed to danger from fermenting filth than cities, that the ineffable atrocities of leaching cesspools and privy-vaults (those perversions of barbarism to which the American rustic clings as to his most precious birthright) do infinitely more to poison air, and soil, and water than all the blunders of city engineers and plumbers combined; and that, granting the worst that can be said of some city sewers which shall be nameless, even a bad sewer is better than none at all—which is merely equivalent to saying that it is better to carry away as much of one's sewage as possible than to keep the whole of it on the premises to decompose under one's nose. And the peril from this fount and origin of evil is augmented a hundredfold where the mania for "modern improvements" has invaded rural households. Long before sewers are thought of—even before the importation of the agonizing pianoforte—the suburban housewife insists on having a bath-room, including that sum and substance of vileness, a pan water-closet on the bedchamber floor, and a kitchen sink and "stationary tubs" down stairs; and these fixtures, commonly constructed in the cheapest and nastiest manner, are connected with an unventilated cesspool, serving as so many inlets to insure the constant pollution of the house atmosphere with the gases of decomposition. Then, in an uncemented basement a "portable furnace" is arranged to transport to the upper rooms not only the cellar-air, but the freely indrawn "ground atmosphere," laden with noxious vapors from the soil-soakage of cesspools or privies. It is not saying too much to affirm that for every one channel of filth-poisoning in a paved and sewered city there are at least three in the average village settlement, and if the evidence of insanitary conditions be found in "not more than one house out of five," it is because, unfortunately, very few physicians in this country have cared to learn how to look for it—familiarity with the doses of drugs and the results of disease being regarded in most of our medical schools as vastly more important thanrerum cognoscere causas.
I am not sufficiently informed of the morbility statistics of African cities to appreciate the full weight of reasonings based upon their alleged comparative salubrity; the occasional scattered returns which I have seen from a few of them show death-rates ranging from 30 to over 40 per 1,000. But I am free to admit, on general principles, that it is less dangerous to let organic matter decompose fully exposed to atmospheric oxygen than to store it in unventilated receptacles to form sulphureted and carbureted compounds, or to saturate an undrained soil with it. It is to be remembered that few, if any, sewage substances are suspected of pathogenic power while in their fresh solid or liquid state: the products of their subsequent chemical changes are what we have to fear; and if these products be liberatedal frescoas fast as they are formed, they are diluted to homœopathic insignificance by the surrounding air. Of the two evils, therefore, the Africo-Hibernian practice of throwing house refuse promiscuously upon the surface is preferable to the American village method of fostering and festering it in cumulative concentration.
As regards the allegation that "the young men at work in the fields were more frequently attacked (by typhoid fever) than the females, who were generally engaged in domestic duties in or about the house," it may be observed: First, that agricultural laborers do not spend all their time in the fields, but sleep in rooms from which, as a class, they carefully exclude all ventilation; second, that, for some unexplained reason, enteric fever seems to have a selective affinity for robust young males. It is an affair of common observation that, under apparently precisely similar conditions, fragile women may resist the infection to which strong men succumb.
Facts, however, are more forcible than words, and I therefore subjoin a few examples of coincidences which have very much the air of causes and consequences. I have excluded instances where water-pollution could be supposed to bear a part, and also those where careful inquiry did not seem to eliminate the possibility of immediate or mediate importation of contagium from a pre-existing case. And let me, at the outset, deprecate the Liebermeisterian criticism that if an adynamic fever with peculiar temperature curve, abdominal symptoms, etc., be not directly traceable to a preceding patient, it is not true typhoid, but only something otherwise indistinguishable from it; or that, without evidence of contagion, a pseudo-membranous angina with grave constitutional depression is not genuine diphtheria, though a remarkably good imitation of the real article. Grant only that there are diseases—call them what you will—which closely resemble the regulation nosological types, that peoplesometimes die of them, and that they are intimately associated with the eating, drinking, or breathing of filth-products, and I shall, for the present, leave the question of diagnosis to be begged by whosoever cares for it.
I.Typhoid.—Large country house with numerous "conveniences." Two "pan closets" on second floor; one in a small windowless hall-apartment, the other in a bath-room adjoining a bed-chamber; basin and bath-wastes led into trap of water-closet; leaden soil-pipe not continued above the line of fixtures, communicating directly with cesspool, and badly corroded at bends of closet-traps. Servants' pan-closet in basement with foul and leaky "retainer;" kitchen and laundry wastes on same horizontal branch, constantly liable to siphonage. Frequent illnesses of minor grade prevailed in this household until the whole plumbing system was reconstructed on a proper plan, since when the inmates have enjoyed excellent health.
II.Typhoid.—Small house in village street. Under the cellar runs the ill-covered channel of a former brook, which receives the sewage of several adjoining tenements. The house-refuse is discharged into this foul trench through an open untrapped conduit in the basement.
III.Typhoid.—Cottage of better class. No plumbing fixtures except kitchen sink, which discharges untrapped into an obstructed and very foul drain; leaching privy-pit on higher ground than the basement, which, with the foundation walls, is uncemented, affording ingress to ground-atmosphere.
IV.Diphtheria.—Elegant mansion, regarded by owner and "practical plumber" as a model of sanitary construction. Soil-pipe extended above roof, but without ventilation at its foot. Materials and workmanship good. On a lateral branch was a down-stairs water-closet into the trap of which the kitchen waste discharged, and into the dip of the running-trap of this horizontal soil-pipe, in the basement, and within a few feet of the furnace, was inserted a servants' hopper-closet without any flushing fixture; excremental matter being, of course, thus retained in the trap a great part of the time, and its decomposition favored by the admixture of hot water from the kitchen. When the water from the boiler was set running, the steam arose freely from this hopper.
V.Diphtheria.—Handsome country-seat. Plumbing work recently overhauled and declared perfect by the plumber. Three foul pan closets and numerous other "conveniences," all leading to unventilated cesspool. In the bedroom occupied by the patient the "safe-waste" from a stationary basin was carried into the soil-pipe, constituting a direct inlet from the cesspool.
VI.Diphtheria.—Presumably "first class" residence. Kitchen and laundry wastes carried from basement into privy-vault, which was filled to above the level of the pipes.
VII.Typhoid?(two irregular cases).—Cottage in good neighborhood. Bath and basin wastes discharging into trap of foul pan-closet with "putty-joints." Two inch tin pipe inserted, with leaky slip-joint, into bend of water closet trap, and carried with several angles to roof; no other ventilation of soil-pipe, which connects with leaching cesspool. Cellar riddled with rat-burrows (indicating probable connection with some old drain), and airbox of furnace made of loosely jointed boards, so as to convey the cellar air to upper part of house.
VIII.Typhoid?(continued fever)—Cottage on high ground. Offensive pan-closet on bedroom floor. Soil-pipe relieved by angular galvanized vent. But carried without other ventilation or trapping to cesspool on lower ground. Kitchen and laundry wastes untrapped and led to a row of buried barrels which were filled with a most malodorous mess, the water being allowed to soak into the soil as best it might.
IX.Diphtheria.—House without plumbing fixtures. Cellar loosely paved with bricks, and saturated with soakage from several privy-vaults on much higher ground and close in the rear; the fæcal-smelling semi-liquid filth actually oozing up between the bricks when they were stepped upon.
X.Diphtheria.—Cottage alleged by the owner, and innocently believed by the tenant, to be "one of the best plumbed houses in the county." Pan closet in a decadent and offensive condition, with untrapped bath waste and insufficiently trapped basin waste led into its seal. Short vent from bend of closet trap to outside of wall, with orifice closed during winter "to prevent water pipes from freezing;" soil-pipe thus without ventilation at top or bottom. Butler's pantry sink connected by tin pipe with earthenware drain, which was badly laid and composed of different sized pipes. Some distance beyond the junction of the soil pipe and wastes, this drain was tapped by a "ventilating" pipe carried into a chimney flue, with an occasional down-draught. Kitchen waste opening directly into an unventilated cesspool. All lead pipes of poorest quality.
XI.Diphtheria.—Country farm-house. No plumbing. Uncemented cellar; living room in wing built directly upon the earth. Overflowing privy-vault within twenty feet and on higher ground, the soakage and surface washing from which had permeated the soil around and under the building.
XII.Diphtheria.—Large and handsome house. Sanitary arrangements satisfactory to plumber. Pan-closet with insufficient flush. Two-inch tin vent from bend of soil-pipe carried with various angles into cold chimney flue. Running under the whole length of the basement was an eight inch earthenware drain receiving the soil-pipe and the wastes from different fixtures; its large caliber and slight grade precluded proper flushing, and it was thickly coated with refuse and chilled grease. Into its upper end was inserted the overflow from a tightly covered cistern, so that the only ventilation of the entire house-drainage system was through the rain-water leader, close to a "mansard" bedroom window.
XIII.Typhoid?—Two small houses of the poorer class, situated on a road at the foot of a steep declivity. No plumbing. Two privy-vaults, a pig-pen, and an indescribably filthy cow stable just behind and above them, from which the washings were traceable into their cellars.
I could extend the list by scores of illustrations of rural house-defects: soil-pipes disjointed from their outlet drains and discharging their sewage under basement floors; cesspools "backing-up" into kitchen sinks or laundry tubs, or pouring a reflux tide through "overflow" pipes into drinking water cisterns; ingenious devices of every sort to deprive the gases from pent-up filth of any escape, save into the dwelling. And these among the "wealthier residents," whose surroundings are commonly supposed to be above suspicion. As regards the unplumbed poor, their chances of inhaling filth-polluted air or imbibing filth contaminated water are often enhanced by inadequate cubic space and faulty construction within doors, and ignorant neglect of the very rudiments of hygiene in the environment; their cellars and wells being sunk in soil saturated with putrescent refuse. In the intermediate agricultural or mechanic class similar conditions frequently exist, their potency for evil depending chiefly upon the porous or retentive character of the soil; precautions to exclude the ground atmosphere from cellars or basements are seldom found; cesspools and privy-vaults are close at hand; and it is a common thing for a couple of adults and two or three children to sleep in a "stuffy" unventilated room with not more than 1,000 or 1,500 cubic feet among them.
From a sanitary point of view it matters little whether the gases from decomposing sewage escape from sodden soil or from a foul sewer; their nature is alike in either case, and the aggregate dose may be even larger in the former instance. But when, and why, and how, they, or any of them, exert their most deleterious influences, are questions which it is impossible to answer in the present state of our knowledge. It is an indisputable fact that people may for a long while be exposed to them without pronounced manifestations of "filth disease"—although such people, in my experience, are seldom thoroughly well, even if not specifically ill. But sooner or later an apparent qualitative change may take place, and an acute zymosis declare itself. I have elsewhere suggested the part that may be borne in this complicated problem by a "personal factor," or temporarily altered individual susceptibility;7but it seems necessary also to assume an alteration in the external conditions; and such alteration is explained by many etiologists on the hypothesis of the importation or evolution of specific pathogenic micro-organisms. That certain varieties of schizophytes are associated with some of the acute infections is beyond doubt; that in a few, such "microdemes" are the conveyers,8if not the causes, of the infection seems proved; but it must be remembered that in the diseases chiefly under consideration no characteristic bacteroidal forms have been defined. In typhoid fever, Klebs describes a bacillus where Letzerich finds only micrococci; according to Wood and Formad, the micrococcus of diphtheria is just like that of the ordinary buccal mucus; indeed, nearly all of the acutest infectious diseases are attributed to these ubiquitous micrococci, indistinguishable from each other in most instances, and divided into species solely on the score of their assumed physiological effects. Admitting all that the most ardent advocates of the germ theory can claim for it, there are at least three possible ways in which filth and fungi may be connected.
1. Taking the view of Naegeli and others as regards the mutability of the bacteria, it is conceivable that the common "scavenger" microphytes may acquire pathogenic properties by successive generations of development amid the products of certain decomposing substances. In favor of this conception may be cited the seemingly gradual intensification of "filth poisoning" in numerous instances; sore throats of a less septic type forerunning outbreaks of diphtheria; diarrhœal derangements preceding enteric fever; and, furthermore, Koch has found both bacillus-spores and micrococci in surface soils, the latter organisms preponderating where the earth is subjected to excremental soakage.
2. Or, accepting the specific classification of the schizomycetes, it may be supposed that some pathogenic germs obtain favorable intermediate conditions for their development and multiplication in these products of decomposition; a supposition almost necessary if the specific-germ theory be applied to enteric or choleraic discharges.
3. Finally, if it be conceded that desiccated spores may retain their specific vitality indefinitely, and be air-wafted almost unboundedly, the predisposing action of our filth emanations maybe imagined to be cumulative, slowly undermining the individual powers of resistance, or rendering certain cell groups an easier prey to the intruding organisms in the struggle for existence.
Which of these hypotheses, if either of them, will ultimately prevail is a question only to be decided by experimental investigations which are beset by a multitude of difficulties and sources of error.—Med. Record.
Owing, no doubt, to the preponderance of horizontality over verticality in the construction of the horse, there results a considerable difficulty in administering medicine to that quadruped, and he frequently has to undergo what may be said to amount to cruelty in the endeavor to persuade him to swallow the unpalatable dose. It is therefore with satisfaction that we bring under our readers' notice a simple and effective invention which promises to do away with this difficulty, and from humanitarian motives we hope to see it widely adopted. It is the joint production of Mr. Philip Fonnereau, of Masons' Arms Yard, Maddox Street, and Mr. Willoughby Fielding, of Lisle Street, Leicester Square, London. The inventors have adopted the sensible and very obvious plan of utilizing that which the horse is trained to tolerate—viz., the bit. It will be seen from the annexed engravings that the invention consists essentially of a tubular bit, with a funnel attached, as shown at Fig. 1. The bit has a hole, which is close to the horse's tongue when in its mouth. The upper part of the apparatus is fitted with a rope, which is passed through a ring in the ceiling of the stable. By this rope the horse's head is gently elevated, so as to prevent the medicine from going in any other direction than down its throat. When it has been properly adjusted, as shown at Fig. 2, the medicine is poured into the funnel, and it immediately runs through the hole into the horse's mouth, and the animal cannot help swallowing it. The apparatus is then removed, and rinsed out for future use. Of course the invention is adapted to liquid medicine only, but we believe it is as easy to prepare medicine in a liquid form as in any other, and therefore there need be no difficulty on that account. We commend this invention to all having the care of horses as a practical means of obviating the perpetuation of a hitherto necessary but now unnecessary cruelty to animals.—Iron.
Fig. 1.Fig. 2.
Fig. 1.
Fig. 1.
Fig. 2.
Fig. 2.
As regards the vascular condition of the cerebrum during natural sleep, there seems to be at present a virtual agreement among physiologists. Whatever views may be held of the immediate or proximate cause, it is generally admitted that during sleep the brain is relatively anæmic. There are well-attested facts enough on record to substantiate this. The brain, denuded of a portion of its cranial covering, has been carefully watched during the waking state and in sleep, and it has been ascertained that, both in man and in the lower animals, the organ is comparatively bloodless during sleep, and its circulation more sluggish than at other times.
In the early part of this century Blumenthal first enunciated this theory, and supported it by the interesting case of a patient who had lost a portion of the right frontal bone; during sleep the brain was seen to be anæmic and in a collapsed condition. Dendy9relates a similar case, which was observed in 1821. But Durham's memoir on the physiology of sleep, which was published in the volume of "Guy's Hospital Reports" for 1860, was the first really thorough and scientific contribution to our knowledge of the vascular state of the encephalon during sleep, and the relation of that state to the phenomena of sleep. To Hammond also, many of whose experiments were made prior to Durham's publication, we are indebted for numerous original observations, and for the most exhaustive and conclusive exposition of the subject yet given to the world.10
We may see that during sleep all the encephalic blood-vessels are under a diminished pressure, as proved in fact by the manometer, and that this lessening of the active flow corresponds with a diminution of cerebral function. Even if no experiments had ever been made, inductive reasoning would have led irresistibly to this conclusion. During the intervals of digestion the gastric mucous membrane is relatively pale and bloodless; the submaxillary gland does not become turgid with blood until it begins to secrete saliva; a muscle in action becomes markedly hyperæmic. It is so with the organs in general. The performance of function is characterized by vascular activity and fullness. If in any part there is a call for work, there is a call for more blood. The nervous system forms no exception to this law, and there is the most intimate and absolute correlation between the evolution of nervous energy and the activity of the circulation. So true is this that it is everywhere admitted that the induction of functional work in any such apparatus as the digestive, the sexual, or the muscular produces a degree of hyperæmia of the apparatus called into action sufficient to prove a serious hinderance to the easy and satisfactory performance of any severe mental task.
Professor Mosso, of Turin, has lately made some interesting experiments on persons who had lost portions of the cranial bones, using Marey's ingenious hydro-sphygmograph. Noting, like others before him, that during sleep the brain diminished in volume, with shrinkage of its blood-vessels, and that the lively blush characterizing its surface during the waking state disappeared, he observed also that any sudden impression, if sufficient to rouse the brain to partial activity, was sure to be attended with an increase of its vascularity and its volume. He has proved, too, that every effort of the intellect is normally accompanied by a diminution of volume in the peripheral parts, the arm, for example, and that, on the contrary, when the cerebral activity is lessened the distant members are augmented in volume. Sleep is always accompanied by a dilatation of the vessels of the extremities, and particularly of the forearm, where this dilatation has repeatedly been measured by Mosso with his registering apparatus. Every excitation from without causes a contraction of the vessels of the forearm of the sleeping subject, and the augmented blood pressure at once produces a renewed afflux of blood to the brain. In this manner the fluctuations of cerebral activity can be followed: a sound, a touch, a ray of light falling on the closed lid of the sleeper, all give rise to modifications of the cerebral circulation—unperceived, doubtless, but possibly the source of dreams.11
The immediate cause of sleep is not simply the shutting off of a portion of the blood current from the brain. There are more important factors. Here Vulpian12is right. The lessening of the blood supply to the encephalon is rather the accompaniment than the cause of sleep. We cannot produce normal sleep in a person simply by exsanguinating his brain, or else we should have in an ice-cap and a hot foot-bath the speediest and most effective of hypnotics. The brain must first be in a certain condition. There must be in the constitution of the supreme nerve centers something that forbids further activity, and with that cessation of activity there will be a lessening of the blood-flow to the brain, in accordance with the physiological law before stated. What is the particular modification of the cortical cells which renders them less fit for the liberation of their special forces, and finally compels a suspension of action, with a diminution of the blood supply? Herbert Spencer has given a very plausible explanation, in accordance with the theory of evolution:
The waste of the nerve-centers having become such that the stimuli received from the external world no longer suffice to call forth from them adequate discharges, there results a diminished impulse to those internal organs which subserve nervous activity, including more especially the heart. Consequently, the nerve-centers, already working feebly, are supplied with less blood and begin to work more feebly, responding still less to impressions, and discharge still less to the heart. And so the two act and react untilthere is reached a state of profound unimpressibility and inactivity. Between this state and the waking state the essential distinction is great reduction of waste, which falls so low that the rate of repair exceeds it.... During the day the loss is greater than the gain, whereas during the night the gain is diminished by scarcely any loss. Hence results accumulation; there is restoration of nerve-tissue to its state of integrity.
According to Mr. Spencer, that rhythmical variation in nervous activity which we see in sleep and waking is the result of adaptation, due to survival of the fittest. "An animal so constituted that waste and repair were balanced from moment to moment throughout the twenty-four hours would, other things equal, be overcome by an enemy or competitor that could evolve greater energy during the hours when light facilitates action, at the expense of being less energetic during the hours of darkness and concealment."13
With some qualification, the foregoing statement is about as satisfactory as any that has yet been offered as to the proximate cause of sleep. During the waking hours the vaso-motor center in the medulla is doubtless under inhibition by the superior centers, and there is relative relaxation of the cerebral arterioles, with dilatation of the capillaries; when the cells of the hemispheres are exhausted, they are no longer able to exercise this inhibition—in common parlance, they no longer powerfully extract the blood—and the vaso-motor center "puts on the brakes"; the blood supply is then no longer sufficient for function, though enough for nutrition.
An ingenious theory has lately been proposed by Preyer, of Jena,14according to which, to use a homely illustration, the fire ceases to burn because the flues are clogged with cinders.
As Preyer puts it, the activity of the cerebrum is a sort of respiration, while its repose is a sort of asphyxia of this organ. It is certain that every psychical act, every thought, involves a certain consumption of oxygen by the nervous substance. During waking, this gas is furnished to the brain in the blood. If the blood supply fails, those forms of activity which we denominate consciousness, attention, volition, and thought cease. This is easily proved by compression of the carotids. It is known that in the waking hours the muscles, as well as the nerves and the nerve-centers, as a consequence of that activity, produce substances easily oxidizable, among which is lactic acid. Some have even attributed the sense of fatigue which we experience after prolonged exertion to the presence of this acid in the blood.15According to Preyer, after the work of the day is done, and the quiet of sleep is sought, the waste materials of which we have spoken, and which he proposes to callponogènes(substances which cause fatigue), being accumulated in the tissues, little by little undergo decomposition, by taking oxygen from the blood. They thus divert a considerable quantity of this gas from the cerebrum, the cells of which, deprived of this element so indispensable to their activity, enter into a state of relative repose. These waste matters are, then, the physical cause of sleep, which will be the more profound and prolonged the more the blood is charged with the excrementitious products of function. Preyer has experimented on animals by injecting varying quantities of lactic acid into their blood, and has produced a deep somnolent condition which could not be distinguished from natural sleep. The use of lactate of sodium in the human subject has sometimes been attended with a like hypnotic effect. Further researches are needed before the question can be considered as settled.—N. Y. Med. Jour.
The usual methods of preparing chlorhydrines are in part inconvenient, in part unsatisfactory in yield. A. Ladenburg therefore proposes the following process, using ethylen-chlorhydrine as an example:
Glycol is heated in a distillery apparatus to 148° C., and aslowcurrent of dry hydrochloric acid passed through it. The water formed and the glycol-chlorhydrine distill over and are collected in tubulated receivers. The temperature of the bath is gradually raised to 160° C., when all the glycol is completely decomposed, except a trifling residue. The distillate is mixed with two or three volumes of ether, and then freed from any hydrochloric acid present with potassium carbonate. The ethereal solution is drawn off, and completely dried over freshly fused potassium carbonate.—Berl. Ber.
At a recent meeting of the Clinical Society of London, Dr. Oliver gave a demonstration of the method he employs for the detection of sugar in the urine by means of test-papers. The test-papers were charged with the carmine of indigo and carbonate of soda. When one was dropped into an ordinary half inch test tube, and as much water poured in as just covered the upper end, and heat applied, a transparent and true blue solution, resembling Fehling's in appearance, was obtained. (A transparent solution could not, at the meeting, be produced from the London water. The characteristic reaction with grape sugar was, however, unimpaired).
If with the paper one drop of diabetic urine had been added, shortly after the first simmer, a beautiful series of color changes appeared; first violet, then purple, then red, and finally straw color; while, on the other hand, one drop of non-diabetic urine induced no alteration of color. The colors returned in the inverse order on shaking the tube, which allowed the air to mingle with the liquid. Reheating restored the colors again.
Confirmation of the presence of glucose was obtained by dropping in a mercuric chloride paper, while the solution was still quite hot, after the complete development of the indigo reaction. Then there was produced immediately a blackish green precipitate. No such precipitation occurred when a drop of non-saccharine urine was under examination by the indigo test; then the blue solution was merely turned into a transparent green one.
This test, as Dr. Oliver pointed out, discovers (a) the normal sugar; (b) the varying proportions of sugar which fill in the gap between the normal amount and that which characterizes diabetes mellitus, as in liver derangements and vaso-motor disturbances; (c) diabetic proportions.
It possesses the following advantages over Fehling's test:
1. It will detect sugar in any proportion in the presence of albumen, peptone, blood, pus, or bile, and as readily as in ordinary diabetic urine.
2. It gives no play of colors with uric acid.
3. It possesses portability, cleanliness, and stability.
Moore's, Trommer's, and Boettger's bismuth tests are all inferior in delicacy.—British Medical Journal.
The author has previously shown the possibility of uniting the fragments of solid bodies by the sole action of pressure. He also established at the same time the possibility of forming chemical compounds by means of pressure. Thus he obtained cuprous sulphide by compressing a mixture of sulphur dust and copper; mercuric iodide, by compressing mercuric chloride with potassium iodide, etc. Finally, by compressing in the same manner mixtures of the filings of different metals, he formed alloys having for equal compositions the same melting points as those obtained by fusion.
The last mentioned facts certainly establish the possibility of causing bodies to enter into chemical reaction by the mere agency of a mechanical energy. This result is closely linked with another obtained during the course of the same investigation: the polymerization of certain simple bodies,e. g., sulphur, by the action of pressure. The author had drawn a general conclusion from his experiments, and had announced that matter takes, below a given temperature, a state corresponding to the volume which it is compelled to occupy.
He has since undertaken a methodical study of the chemical reactions accomplished by the action of pressure. He had already shown the possibility of forming metallic arsenides by compressing mixtures of arsenic and of the filings of different metals (Bulletin de l'Académie Royale de Belgique, t. v., 1883), and he now communicates the results obtained by compressing mixtures of sulphur and of certain metals or non-metals. The results not merely confirm the author's former conclusions, but they throw a new light on the relations of organic and inorganic chemistry, and exhibit the so-called simple bodies as capable of assuming a peculiar constitution varying according to the conditions in which they are placed, and the actions to which they are submitted.
He used the metals in the state of fine filings immediately mixed with flowers of sulphur previously thoroughly washed. The mixtures were made in atomic proportions and were submitted to a preliminary pressure of 6,500 atmospheres. They then assumed the state of a hard compact mass, showing, on examination with the microscope, that the reaction of the sulphur and the metal had taken place wherever the elements were in contact. The mass obtained was then reduced into fine powder and compressed again from twice to eight times.
1.Sulphur and Magnesium.—After six compressions there was obtained a gray mass with a feebly metallic surface luster. It dissolves in water at 50° to 60° with a slow escape of hydrogen sulphide, the liquid becoming of a golden yellow. A drop of hydrochloric acid occasions immediately a very strong escape of hydrogen sulphide, while free sulphur is deposited. Hence magnesium and sulphur combine under the action of pressure, forming magnesium sulphide and possibly a polysulphide.
2.Sulphur and Zinc.—Three compressions yield a block deceptively similar to native blende with metallic luster. Dilute sulphuric acid dissolves the block slowly with an escape of hydrogen sulphide.
3.Sulphur and Iron.—After four compressions a block is obtained which the file scarcely touches. Dilute sulphuric acid dissolves it easily with continuous escape of hydrogen sulphide. If the product of compression is heated in a closed tube no luminous phenomenon is observed, the body entering into tranquil fusion. Hence the potential heat of the free sulphur and iron has been realized during the compression.
4.Sulphur and Cadmium.—Three compressions give a yellowish-gray homogeneous mass. The powder is yellow, but less pure than that of cadmium sulphide obtained by precipitation. Strong hydrochloric acid dissolves the mass with escape of hydrogen sulphide.
5.Sulphur and Aluminum.—Result incomplete. After five compressions a mass is obtained which, in contact with moist air, gives off an odor of hydrogen polysulphide.
6.Sulphur and Bismuth.—The combination takes place with great ease.
7.Sulphur and Lead.—The combination is still more easy.
8.Sulphur and Silver.—The action is slow; eight compressions are necessary.
9.Sulphur and Copper.—Three compressions complete the combination. When the product of the compression is heated, there is no development of heat or light.
10.Sulphur and Tin.—Three compressions give a block which yields a yellowish-gray powder, easily soluble in a hot solution of sodium sulphide. Stannic sulphide is therefore formed by the compression of sulphur and tin.
11.Sulphur and Antimony.—After two compressions we obtain a gray-black mass having the color and luster of stibine. When powdered it dissolves with ease in hot hydrochloric acid, giving off hydrogen sulphide.
12.Sulphur and Red Phosphorus; Sulphur and Carbon.—Result entirelynil; there is produced not the least trace of phosphorus sulphide nor of carbon sulphide.
The negative results just mentioned have an especial interest. It is established that red phosphorus has a higher specific gravity than white phosphorus, that of the former being 1.96, and that of the latter 1.82. The author's former researches (Bulletins de l'Académie Royale de Belgique, 49, p. 323, 1880) have shown that if sufficient pressure is applied to a body capable of assuming several allotropic states, it takes under pressure the state corresponding to its greatest density. It is consequently impossible to transform red phosphorus into white phosphorus by pressure. But we know, on the other hand, that red sulphur and red phosphorus may be mixed with impunity at common temperatures without combination ensuing; to produce combination the temperature must be raised to about 260°, the point of transformation of red phosphorus into white phosphorus.
It is thus established that red phosphorus must first be changed from its allotropic condition before entering into combination with sulphur. The pressure opposing this change renders also the act of combination impossible; red phosphorus appears to us like a body which has lost its chemical faculties.
Thus, the combination of an element with itself,i. e., its polymerization, has really the effect of extinguishing its energy, rendering it incapable of fulfilling certain functions. The chemistry of red phosphorus, more simple than that of white phosphorus, may be considered as the chemistry of a deadened body. The phosphorus which is found in combination with sulphur is phosphorus sulphides, and that which enters into combinations of other kinds, is certainly not phosphorus in the red state; it is even possible, if not probable, that it is not even white phosphorus, but a substance still unknown in the free state.
We arrive at a similar but more complete conclusion as to the nature of carbon. It is known that the affinity of carbon for sulphur and even for oxygen only becomes manifest at a temperature bordering upon redness. Is not this tantamount to saying that, in order to enter into combination with another body, carbon, like red phosphorus, must first change its allotropic condition? This view is supported by the following considerations: The specific heat of amorphous carbon, and,a fortiori, that of graphite and diamond, form exceptions to the law of Dulong and Petit; they are too small by more than one-half. They would be normal if the atomic weight of carbon were greater than it really is; in other words, free carbon were a polymer of combined carbon. Rose has found that at a temperature of about 500° the specific heat of carbon agrees with the law of Dulong and Petit. At this temperature carbon undergoes a beginning of depolymerization,i. e., its chemical affinities reappear, and it burns readily in oxygen. Do not these facts show a complete parallelism between the chemical history of phosphorus and that of carbon?
Crystalline carbon, and even free amorphous carbon, are without chemical activity at the ordinary temperature; but when, in consequence of a rise of temperature, they take another state, they are transformed into a new kind of carbon, constituting a fourth allotropic state, and endowed with a prodigious capacity of combination. If these conclusions are well founded, we may venture a step further and ask, if the carbon which enters into the composition, not of mere organic compounds, but of organized bodies, is not a carbon of still another allotropic state characterized by the appearance of new properties or forms of combination which find their expression in the vital phenomena.
In other words, a derivative of carbon, before forming part of a living body, must first undergo in its atoms a transformation similar to that which permits amorphous carbon to enter into the composition of organic compounds. In this order of ideas the carbon of organic chemistry would be merely a first deadened form of the carbon of biological chemistry, while free carbon is merely the defunct remains of the carbon of organic chemistry.—Bulletin de la Société Chimique de Paris; Chem. News.
The earth's crust consists in part of eruptive rocks, in part of sedimentary rocks. Both of them have served from time immemorial for building purposes; but at a very early period they were the only source from which weapons and tools could be made. Subsequently metals became known, and were employed for this purpose.
Metals are rarely met with in a pure state, but generally in combination with oxygen or sulphur. If we examine the original material of which the earth was composed, and which is frequently injected through crevices in the earth's crust, and the superjacent sediment as eruptive rock, we find it to be a mixture of different substances of a complex nature. It contains silicon, aluminum, iron, calcium, magnesium, potassium, and sodium. None of these are in a free state, but are combined with oxygen. Silicon, the lighter metals, and heavy iron do not exhibit their true metallic character, having all been changed into stone-like compounds, "calcified by contact with vital air," as the old chemists expressed it.
Of the heavy metals that are of such importance to civilization I have only mentioned iron, for this alone, in its compounds, takes any considerable part in the rock formations. Other heavy metals are met with in smaller quantities in the rocks. They are scarcely taken into account by geologists who consider the earth as a whole, but it is these rare guests that are of the greatest importance to civilization.
The metals are met with as silicates in the eruptive masses; they are also found as oxides or sulphides, scattered through different eruptive rocks in small granules.16Besides these, the "ores," which are workable metallic compounds, are here and there concentrated in crevices or fissures, which exist in eruptive as well as in sedimentary rocks.
Ironis met with as oxide in the eruptive rocks, in fissures, and finally in thick strata and deposits within the sediment; whole mountains consist of iron ore.
Tinoccurs as oxide (tin stone), scattered through eruptive masses rich in quartz, also in fissures.
Copper, combined with sulphur, is found distributed through dark eruptive rocks, poor in silica, and also in fissures in those regions.
Goldandsilverare mixed in smaller quantities with ores of other metals.
All these are continually exposed to atmospheric agencies toward which they act very differently. The oxidized ores of iron and tin do not change their character. The sulphur compounds, at least when near the surface, are oxidized, and hand in hand with this process goes the partial reduction of certain metals to the metallic state. Gold and silver, and to a less extent copper, are subject to this change; they are unmasked and are exposed to day light, not as stones, but as brilliant, malleable metals. Finally, the heavy ores and metallic particles are loosened from the rocks by the destructive action of water, floated off, elutriated, and washed. In undisturbed mountain ranges the mineral treasures lie in masses before our eyes.
The native shining and malleable metals (gold, silver, and copper) naturally first attracted the attention of man. They may have used the separate nuggets for ornaments as they found them, or after hammering them together into plates. This was surely the first step in the use of metals. It can scarcely be supposed that this use of soft native metals contributed much to the progress of mankind, and it is highly probable that in those early times the noble metal had but little value. The shining particles, as long as the natural supply lasted, seemed like worthless tinsel. Copper, which can be made into tools and vessels, as well as soft, poor weapons, was more highly prized. Such materials were not, indeed, suitable and able to take the place of stone tools and weapons; nevertheless, this working of metals served as preparation for the more complicated work of later times. Man learned to hammer and shape metals, and he found out that the operation was much facilitated by heating the metal.
The discovery of iron meteorites may have had some value. In these the smith first became acquainted with the properties of a hard metal. But I would not attach too much importance to this. The art of working metals is not the possession of a people that have a few meteoric knives. In my opinion the metallurgical preparation of the hard metals from their ores is alone decisive on this point.
The volks' sagas frequently mention some god or hero, who discovered and taught metallurgy, yet there is scarcely any doubt that the "god," in most cases, was human ingenuity led by chance.
We have already seen that only certain metals are found native, while the hard metals under normal conditions remain in the form of oxide or mineral. They have a strong affinity for the oxygen of the air, and can only be separated and converted into metals by powerful chemical agents. There isonesubstance which has a still more powerful attraction for oxygen than those metals. This is ignited carbon, which, in its fight with the metallic oxides, robs them of their oxygen.
Carbon has been separated from the carbonic acid of the air by the life-giving force of the sun, and vegetable life dependent upon it. But the isolated element waits impatiently for the impulse that will enable it to unite with the vital air under flame and heat. Men that know how to utilize this process of nature possess the means of resurrecting those metallic treasures which, without its powerful assistance, would remain forever hidden from their eyes. But accident, as we have said, pointed out the way.
In numerous places visited by primeval man, as hunter and fisherman, and afterward as nomad, conflagrations broke out. Not unfrequently whole forests were burned, either intentionally or not. It could not be otherwise than that the earth's surface would get red hot in such places, and if a strong wind favored it, this would suffice to open these treasures. The glowing charcoal would rob the ores of their oxygen and leave the pure metal as melted drops or cakes.17Copper, tin, and iron ores could have been reduced in this way; mankind not only knew the result but also the method of reducing metals.
This process took place not once merely, but thousands of times in various parts of the earth, and thus, in my opinion, metallurgy may have become known to different races of people and at different times.
A simple trench in the ground, in which a heap of glowing coals and some pieces of ore could be subjected to a strong draught of air, suffices, under favorable circumstances, for the preparation of the metal; the oldest metallurgists had scarcely any more complete means at hand for their work.
In such primitive furnaces the well known and soft metals would naturally be worked first, and afterward copper, tin, and iron would be obtained from their ores. A variety of substances that occur together in nature would be smelted together in mixtures, and different metals would naturally be mixed and a great variety of products obtained.
The oldest civilized races used bronze for a long space of time as their chief useful metal, although some neighboring races understood the metallurgy of iron. These facts, which are in glaring contradiction to the present condition of things, require some explanation.
First it must be mentioned thatironfrequently contains injurious contaminations, sulphur, phosphorus, etc., and that it must have been very difficult for these primitive metallurgists to remove these contaminations, and to introduce the proper quantity of carbon into the iron. We must also consider that even a good, pure steel would be a useless product unless it was worked by a skillful and experienced smith. Finally, iron is much more rapidly destroyed by oxidation than bronze. These negative considerations certainly favored the rule of bronze for a long time.
The following facts must be fixed in mind regarding the manufacture of bronze in olden times:
1. In many districts copper and tin ores are found near together (as in Cornwall), so that under these circumstances bronze could have been obtained by smelting both at once, and together.
2. In olden times only the upper horizon of copper deposits were worked in all districts. In these, as we know, the ores are mostly oxides (with native copper). Such ores are easily worked and yield largely.
3. In regard to the mixing of metals, the metallurgists everywhere must have soon learned by experience that the metal remained soft and red when too little tin was added, while too much tin made it light colored and lustrous, but, at the same time, very brittle. Hence, we find that among all peoples the alloys used for weapons contain from 6 to 16, or, more closely, 8 to 12 per cent. of tin. These mixtures have been found to do the best.
4. Bronzes, as we shall see below, by slight admixtures and certain treatment, can be made so tough and hard that they will compare with moderately hard steel.
So we see: The metal was useful, and there was an excess of rich and easily worked ores. Under such conditions, of course, the age of bronze would flourish a long time.
Zinc ores frequently occur on copper beds, and yet zinc is rarely found in quantity worth mentioning in the bronzes of the ancients. There are two reasons for this:
1. Near the surface of the earth zinc occurs as calamine (silicate of zinc), which is a gray, unattractive, earthy looking mineral, not heavy enough to be taken for a metallic ore, and would naturally be thrown away and not put in the furnace.
2. If some zinc ore did get into the furnace, part of it would be volatilized and part oxidized by subsequent smelting.
In later times, however, we find zinc ores used a good deal. We can distinguish three types of zinc alloys:
1. Copper with 10 to 20 per cent. zinc produces a red metal, red brass, which is similar to bronze that is poor in tin.
2. Copper with 20 or 30 (and even 40) per cent. of zinc, gives a yellow metal (yellow or ordinary brass), which has more of a golden color than bronze with much tin, but quite brittle.
3. Statuary metal, which is made of copper with quite a good deal of zinc and little tin (often lead) can be called brass containing tin.
All three types may be used for casting (ornaments, statues, and coin), but are not useful for tools or weapons, because they have not sufficient strength.
After discussing the natural association of ores, and the most important alloys of copper, we will turn to the analyses of antique alloys. I have found it necessary to divide them into two groups:
1. Alloys from which the weapons and tools wereforged. These are pure and genuine bronzes. I shall designate them as malleable metals or weapon bronzes.
2. Alloys from which ornaments, vessels, statues, and coin werecast. Some of these contain lead, some zinc, and some are varieties of our brass. I shall designate these as cast metals or ornamental alloys. Those substances present in some quantity were evidently put inintentionally, and I have classed them as admixtures, while the unintentional ones in small quantities I have designated as impurities.