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Still, we are not altogether ignorant; some circumstances appear to be followed by effects so definite, that we may almost consider we have before us, in true position, cause and effect. Let us look at this position in reference to the simple influence of temperature on the value of life.
If we observe the fluctuation of the thermometer by the side of the mortality of the nation at large, no calculable relationship seems, at first sight, to be traceable between the one and the other. But if, in connection with the mortality, care be taken to isolate cases, and to divide them into groups according to the ages of those who die, a singular and significant series of facts follow, which show that after a given age a sudden decline of the temperature influences mortality by what may be considered a definite law. The law is, that variations of temperature exert no marked influence on the mortality of the population under the age of thirty years; but after the age of thirty is reached, a fall of temperature, sufficient to cause an increased number of deaths, acts in a regular manner, as it may be said, in waves or lines of intensity, according to the ages of the people. If we make these lines nine years long, we discover that they double in effect at each successive point. Thus, if the, fall in the temperature be sufficient to increase the mortality at the rate of one person of the age of thirty, the increase will run as follows: 1 death at 30 years of age will become 2 deaths at 39 years of age, 4 at 48 years, 8 at 57 years, 16 at 66 years, 33 at 75 years, and 64 at 84 years.
In these calculations nothing seems to be wanting that should render them trustworthy; they resulted from inquiries conducted on the largest scale; they were computed by one of our greatest authorities in vital statistics, the late Dr. William Farr, and they accord with what we gather from common daily observation. They supply, in a word, the scientific details and refinements of a rough estimate founded on universal experience, and they lead us to think very gravely on many subjects which may not have occurred to us before, and which are as curious as they are important.
We often hear persons who know little about vital phenomena, by which term I mean nothing mysterious, but simply the physics embraced in those phenomena which we connect with form and motion under the term life, harping on the one string, that man knows nothing of the laws of life and death. But what an answer to such presumption do the facts rendered above supply. Life and death are here reduced, on given conditions, to reasonings as clear and positive as are the reasonings on the development of heat by the combustion of fuel. It is not necessary for the vital philosopher to go out into the towns and villages to take a new census of deaths to enable him to give us his readings of the general mortality under the conditions specified. He may sit in his cabinet, and, as he reads his thermometer day by day, predict results. There is a fall of temperature that shall be known by experience to be sufficiently deep and prolonged to cause an increase of one death among those members of the community who have reached thirty years. Then, rising by a definite rule, there have died sixty-four, in proportion to that one, of those who have reached eighty-four years. This is sound calculation, and it leads to reflection. It leads one to ask, what, if the law be so definite, are curative and preventive medicine doing meanwhile, that they shall not disturb it? I fear that they hardly produce perturbations, and I do not see why they should; because, as the truth opens itself to the mind, the tremendous external change in the forces of the universe that leads to the result, is not to be grappled with nor interfered with by any specific method of human invention. The cause is too general, too overwhelming, too grasping. It is like the lightning stroke in its distance from our command; but it is widely spread, not pointed and concentrate; prolonged, not instantaneous; and, by virtue of these properties, is so much the more subtile and devastating.
At first it seems easy to explain the reason why a sudden fall in temperature should lead to an increase in the number of deaths, and it is to be admitted that, to a certain extent, the reason is clear.
ANIMAL POWER AT DIFFERENT PERIODS OF LIFE.
Without entering on the question whether heat is the animating principle of all living organisms, we may accept that in the evolution of heat in the body we have a measurement of the capacity of the body to sustain motion, which is only another phrase for expressing the resistance of the body to death. For example, if we assume that a healthy man of thirty respires sufficient air per day to produce as much heat as would raise fifty pounds of water at 32 deg. Fahr. to 212 deg. Fahr., and if we assume that a man of sixty in the same temperature is only able to respire so much air as shall cause him to evolve so much heat as would raise forty pounds of water from 32 deg. to 212 deg., we see a general reason why the older man should feel an effect from a sudden change in the temperature of the air which the younger would not feel; and if we assume, further, that a man of eighty could in the same time produce as much heat as would raise only twenty pounds of water from 32 deg. to 212 deg., we see a good reason why the oldest should suffer more from a decrease of external temperature than the other two. It is necessary, however, to know more than this general statement of an approximate fact; we ought to understand the method by which the reduction of temperature influences, and the details of the physiological process connected with the phenomena. When a human body is living after the age when the period of its growth is completed and before the period of its decay has commenced, it produces, when it is quite healthy, by its own chemical processes, so much heat or force as shall enable it, within given bounds, (1) to move its own machinery; (2) to call forth, at will, a limited measure of extra force which has been lying latent in its organism; and (3) to supply a fluctuating loss that must be conveyed away by contact with the surrounding air, by the earth, and by other bodies that it may touch, and which are colder than itself. There is thus produced in the body, applied force, reserve force, and waste force, and these distributions of the whole force generated, when correctly applied, maintain the perfect organism in such balance that life is true and steady. So much active force carries with it the power to perform so much labor; so much reserve force carries with it the power to perform a measure of new or extra labor to meet emergencies; so much waste force enables the body to resist the external vicissitudes without trenching on the supply that is always wanted to keep the heart pulsating, the chest breathing, the glands secreting or excreting, the digestive apparatus moving, and the brain thinking or absorbing.
Let us, even in the prime of manhood, disturb the distribution of force ever so little, and straightway our life, which is the resultant of force, is disturbed. If we use the active force too long, we become exhausted, and call on the reserve; if we continue the process, the result is failure more or less perfect, sleep, and, in the end, the last long sleep. Let us, instead of exhausting the force, cut it off at the sources where it is generated; let us remove the carbon or coal that should go in as fuel food, and we create prostration, and in continuance a waning animal fire, sleep, and death; or let us, instead of removing or withdrawing the supply of fuel, cut off the supply of air, as by immersion of the body in water, or by making it breathe a vapor that weakens the combination of oxygen with carbon—such a vapor as chloroform—and again we produce, at once, prostration, sleep, or death, according to the extent to which we have conducted the process. Lastly, if instead of using up unduly the active and reserve force, or of suppressing the evolution of force by the withdrawal of its sources, we expose the body to such an external temperature that it is robbed of its heat faster than it can generate it; if to supply the waste heat we draw upon the active and reserve forces, we call forth immediately the same condition as would follow extreme over-exertion, or suppression of the development of force; we call forth exhaustion and sleep, and, if we go far enough, death.
We have had in view, in the above description, a man in the prime of life, in the center of growth, and decay. In regard to the force of animation in him, let us look at him now retrospectively and prospectively. In the past his has been a growing, developing body, and in the course of development he has produced an excess of force commensurate with the demands of his growth; this has enabled him gradually to bear more fatigue and more exposure, without exhaustion, and even with ease, until he has reached his maximum. When he has stopped in development, when he stands on a fair level with the external forces that are opposed to him, then his own force, for a short time balanced, soon stands second in command. He feels cold more tenderly; if his rest be broken, the demand for artificial heat is more urgent; if he lose or miss food, he sinks quickly; and, returning to our facts, as to the influence of the external temperature on mortality, these are the reasons why a fall in the thermometer sweeps away our population according to age so ruthlessly and decisively.
If we analyze the facts further by the side of the diseases which kill the old, we find those diseases to be numerous in name, but all of two types. They are diseases which of themselves tend either to produce undue loss of force, or that tend to prevent the development of force at its origin. Thus affections which are accompanied with exhaustive loss of fluids from the body, such as diabetes, dropsies, and haemorrhages, are of the first class; affections in which due supply of air to the lungs is prevented are of the second class, especially bronchitis, a disease so commonly assigned as the cause of the deaths among the members of the aged and enfeebled population, that succeed immediately on an extreme fall of the thermometer.
FALL OF TEMPERATURE—MODE OF ACTION.
In what has been written above I have stated simply and in open terms the fact that the fall of temperature produces a specified series of results, by reducing the force of the living organism, and disposing it to die. We may from this point investigate, from a physiological point of view, the mode by which the effect is produced in the economy. How does the decline of temperature act? Is the process simple or compound?
EXTRACTION OF HEAT.
The process is compound, and into it there enter three elements. In the first place, the body is robbed rapidly of its waste force, and the reserve and active elements of force are, consequently, called upon to the depression of the organism altogether. This obtains because the medium surrounding the body, the air, unless it be artificially heated, removes from its contact with the body a larger proportion of heat than can be spared; and it might be possible to produce such an influence on the body by sudden extraction of its heat as to destroy it at once by the mere act. If a man could be surrounded with frozen mercury he would die instantaneously, as from shock, by the immediate extraction of his heat. But in ordinary cases, and under ordinary circumstances, the mere rapid extraction of waste heat is not sufficient to account for all the mischief produced by a low temperature; for by artificial warmth and non-conducting garments, we counteract the influence, and that, too, in a manner which proves pretty successful. We may, therefore, leave this element of extraction of heat as a most important, but not as the sole, agent of evil.
SUPPRESSED OXIDATION.
The second element is the effect on the process of oxidation of blood under the influence of cold. We all are aware that if a portion of dead animal or vegetable matter be placed at a low temperature, it keeps for a considerable time; and we have evidence of dead animals which, clothed in thick ribbed ice, have been retained from putrefaction for centuries. Hence we say that cold is an antiseptic as alcohol is, and chloroform, and ammonia, and other similar bodies. Cold is an antiseptic then, but why? Because it prevents, even in the presence of a ferment, the union of oxygen gas with combustible matter. The molecules of oxygen, in order that they shall combine, and in their combination evolve heat, require to be distributed, and to be distributed by the form of motion known as heat; deprive them of this activity, and they come into communion with themselves, are attracted to each other, and lose to the extent of this attraction their power of combining with the molecules of other bodies for which they have an affinity. In an analogous, but more obvious way, we may see the same effect of motion in the microscopic examination of blood. In the blood, while it is circulating briskly in its vessels, there are distributed through it, without contact with each other, the millions of oxygen carriers called blood corpuscles. In the circulation in the free channels of the body, the arteries and veins, it is motion that keeps these corpuscles apart; we draw a drop of blood and let it come to rest on the microscope glass, and as the motion ceases the separated corpuscles run together, and adhere so firmly that we cannot easily separate them without their disintegration. If we were able to drive them in this state round the body, through the vessels, they would not combine readily with the tissues; they have, in fact, forfeited the condition necessary for such combination. So with the oxygen they carry; when its invisible molecules are deprived of the force called heat, which is motion, they do not readily combine with new matter. But perfect combination of oxygen and carbon in the blood is essential to every act of life. In the constant clash of molecule of oxygen with molecule of carbon in the blood lies the mainspring of all animal motion; the motion of the heart itself is secondary to that. Destroy that union, however slightly, and the balance is lost, and the animal body is, in a plain word, ill.
Cold or decreased temperature, below a given standard, which for sake of comparison we may take at a mean of 40 deg. Fahr., reduces this combination of oxygen and carbon in blood. In my Lettsomian lectures to the Medical Society of London, delivered in 1860, I entered very fully into this subject, and illustrated points of it largely by experiment. Since then I have done more, and although I have not time here to state the details of these researches, I will epitomize the principal facts. I found then that, by exposing blood in chambers into which air can pass in and out, the blood could be oxidized at temperatures of 70 deg. if the distribution of air and blood were effectually secured, and I also found a proper standard of oxidation from a proper temperature. Afterward I proceeded to test for combination at lower temperatures, and discovered a gradually decreasing scale until I arrived at 40 deg. Fahr., when efficient combination ceased. Of course, my method was a very crude imitation of nature, but it was sufficient to show this fair and reliable result, that the oxidation of blood decreases as the temperature of the oxygen decreases.
From this point I went to animal life itself. I exposed animals to pure cold oxygen and to cold atmospheric air, and compared the results with other experiments in which animals of similar weight were exposed to warm air and warm oxygen. The facts gleaned were most important, for they proved conclusively that the products of combustion, that is to say, the products resulting from the union of oxygen and carbon, were reduced in proportion as the temperature of the oxygen was reduced. In the course of this inquiry another singular and instructive fact was elicited. It has been long known that at ordinary temperature, say 60 deg., pure neutral oxygen does not support animal life so well as oxygen that is diluted with nitrogen. In the nitrogen the molecules of oxygen are more freely distributed under the influence of motion, that is the meaning of the observed fact. What, then, would be the respective influence of low and high temperatures on the respiration of pure oxygen? To settle this question, animals of the same size and weight were placed in equal measures of oxygen gas and common air at a temperature of 30 deg. Fahr., and with the inevitable result that the animal in the pure oxygen ceased to respire one-third sooner than did the animal in common air. Carrying the inquiry further, I found that if the oxygen gas were warmed to 50 deg. Fahr., the respiration was continued six times as long as in the previous experiment, while if the warming were carried to 70 deg., it was sustained twenty-four times as long. I reversed the experiment; I made oxygen with cold produce anaesthetic sleep in a warm-blooded animal.
I need not carry this argument further; it is the easiest of the demonstrative facts of physiological science that reduction of temperature lessens the combining power of oxygen for blood, and therewith causes a reduction of animal force, and a tendency to arrest of that force, which, in the end, means death.
MECHANICAL COLD.
The third element in the action of cold is more purely mechanical, and this, though in a sense secondary, is of immense import. When any body, capable of expansion by heat, that is to say, by radiant motion of its own particles, is reduced in temperature, it loses volume, contracts, or shrinks. The animal body is no exception to this rule; a ring that will fit tightly to the warm finger will fall off the same finger after exposure to cold. The whole of the soft parts shrink, and the vessels contract and empty themselves of their blood. Cold applied to the skin in an extreme degree blanches the skin, and renders it insensible and bloodless, so that if you prick it it does not bleed, neither does it feel. In cases where the body altogether is exposed to extreme cold this shrinking of the external parts is universal; the whole surface becomes pale and insensible; the blood in the small vessels superficially placed is forced inward upon the heart and vessels of the interior organs; the brain is oppressed with blood; sleep, or coma, as it is technically called, follows, and at last life is suspended.
In exposure to the lowest wave of temperature in this country these extreme effects are not commonly developed; but minor effects are brought out which are most significant. In particular, the effect on the lungs is strongly marked. The capillary vessels of the lungs, making up that fine network which plays over the computed six hundred millions of air vesicles, undergo paralysis when the cold air enters, and in proportion as such obstruction from this cause is decisive, the blood that should be brought to the air vesicles is impeded, and the process of oxidation is mechanically as well as chemically suppressed. The same contraction is also exerted on the vessels of the skin, driving the blood into the interior and better protected organs. Hence the reason why on leaving a warm room to enter a cold frosty air there is an immediate action of the visceral organs from pressure of blood on them, and not unfrequently a tendency to diarrhoea from temporary congestion of the digestive tract. Three factors are at work, in fact, whenever the low wave of temperature affects the animal body; abstraction of heat from the body, beyond what is natural; arrest of chemical action and of combustion; paralysis of the minute vessels exposed to the cold.
COMBINED EFFECTS.
We cannot view the extent of change in the organic life induced by the low wave of heat without seeing at once the sweep of mischief which exposure to the wave may effect. It exerts an influence on healthy life in the middle-aged man, and I know of no disease which it does not influence disastrously. Is the healthy man exhausted, it favors internal congestion; has he a weak point in the vascular system of his brain, it renders that point liable to pressure and rupture, with apoplexy as the sequence; is he suffering from bronchial disease, and obstruction, already, in his air passages, here is a means by which the evils are doubled; has he a feeble, worn-out heart, it is unable to bear the pressure that is put upon it; has he partial obstruction of the kidney circulation, he is threatened with complete obstruction; is he indifferently fed, he is weakened generally. It is from this extent of action that the mortality of all diseases runs up so fast when the low wave of heat rolls over the population, affecting, as we have seen, the feeblest first.
Another danger sometimes follows which is remote, but may be fatal, even to persons who are in health. It is one of the best known facts in science that when a part of the surface of the body has been exposed long to cold, the greatest risk is run in trying suddenly to warm it. The vessels become rapidly dilated, their coats relax, and extreme congestion follows. But what is true of the skin is true equally, and with more practical force, of the lungs. A man, a little below par, goes out when the wave of temperature is low, and feels oppressed, cold, weak, and miserable; the circulation through his lungs has been suppressed, and he is not duly oxidizing; he returns to a warm place, he rushes to the fire, breathes eagerly and long the heated air, and adds to the warmth by taking perchance a cup of stimulant; then he goes to bed and wakes in a few hours with what is called pneumonia, or with bronchitis, or with both diseases. What has happened? The simple physical fact of reaction under too sudden an exposure to heat after exposure to cold. The capillaries of the lungs have become engorged, and the circulation static, so that there must be reaction of heat, inflammation, before recovery can occur. Nearly all bronchial affections are induced in this manner, not always nor necessarily in the acute form, but more frequently by slow degrees, by repetition and repetition of the evil. Colds are often taken in this same way, from the exposed mucous surfaces of the nose and throat being subjected first to a chill, then to heat.
The wave of low temperature affecting a mixed population finds inevitably a certain number of persons of all ages and conditions on whom to exert its power. It catches them too often when they least expect it. An aged man, with sluggish heart, goes to bed and reclines to sleep in a temperature, say, of 50 deg. or 55 deg.. In his sleep, were it quite uninfluenced from without, his heart and his breathing would naturally decline. Gradually, as the night advances, the low wave of heat steals over the sleeper, and the air he was breathing at 55 deg. falls and falls to 40 deg., or it may be to 35 deg. or 30 deg.. What may naturally follow less than a deeper sleep? Is it not natural that the sleep so profound shall stop the laboring heart? Certainly. The great narcotic never travels without fastening on some victims in this wise, removing them, imperceptibly to themselves, into sleep ending in absolute death.
SOME SIMPLE RULES.
The study of the physiological influence of the wave of low temperature, and of its relation to the wave of mortality, suggests a few rules, simple, and easily remembered.
1. Clothing is the first thing to attend to. To have the body, during variable weather, such as now obtains, well enveloped from head to foot in non-conducting substance is essential. Who neglects this precaution is guilty of a grievous error, and who helps the poor to clothe effectively does more for them than can readily be conceived without careful attention to the subject we have discussed.
2. In sitting-rooms and in bedrooms it is equally essential to maintain an equable temperature; a fire in a bedroom is of first value at this season. The fire sustains the external warmth, encourages ventilation, and gives health not less than comfort.
3. In going from a warm into a cold atmosphere, in breasting the wave of low temperature, no one can harm by starting forth thoroughly warm. But in returning from the cold into the warm the act should always be accomplished gradually. This important rule may readily be carried in mind by connecting it with the fact that the only safe mode of curing a frozen part is to rub it with ice, so as to restore the temperature slowly.
4. The wave of low temperature requires to be met by good, nutritious, warm food. Heat-forming foods, such as bread, sugar, butter, oatmeal porridge, and potatoes, are of special use now. It would be against science and instinct alike to omit such foods when the body requires heat.
5. It is an entire mistake to suppose that the wave of cold is neutralized in any sense by the use of alcoholics. When a glass of hot brandy and water warms the cold man, the credit belongs to the hot water, and any discredit that may follow to the brandy. So far from alcohol checking the cold in action, it goes with it, and therewith aids in arresting the motion of the heart in the living animal, because it reduces oxidation.
6. Excessive exercise of the body, and overwork either of body or of mind, should be avoided, especially during those seasons when a sudden fall of temperature is of frequent occurrence. For exhaustion, whether physical or mental, means loss of motion in the organism; and loss of motion is the same as loss of heat.
One further consideration, suggested by the subject of this paper, has reference to the bearing of the public toward the labors of the medical man in meeting the effects of the low wave of heat. The public, looking on the doctor as a sort of mystical high priest who ought to save, may often be dissatisfied with his work. Let the dissatisfied think of what is meant by saving when there is a sudden fall in the thermometer. Let them recall that it is not bronchitis as a cause of death, nor apoplexy, nor heart disease, as such, that the doctor is called on to meet; but an all-pervading influence which overwhelms like the sea, and against which, in the mass, individual effort stands paralyzed and helpless. When the doctor is summoned the mischief has at least commenced, and, it may be, is so far over that treatment by mere medicines sinks into secondary significance. Then he, true minister of health, candid enough to bow humbly before the great and inevitable truth, and professing no specific cure by nostrum or symbol, can only try to avert further danger by teaching elementary principles, and by making the unlearned the participators in his own learning.—The Asclepiad.
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THE TREATMENT OF GLAUCOMA.
As this disease is so fatal to vision, any remedy that may be suggested to diminish the frequency of its termination in blindness cannot fail to be read of with interest. M. Nicati, in the Revue generate de clinique et de therapeutique, has had marked success in the treatment of glaucoma by drainage of the posterior chamber, either by sclerotomy or by sclero-iritomy, as the conditions of the individual case may require.—N.Y. Med. Jour.
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A TWIN SCREW LAUNCH RUN BY A COMPOUND ENGINE.
The launch shown in our illustration was built in New Westminster, British Columbia, Canada. She is 42 ft. keel and 7 ft. beam, and has 4 ft. depth of hold. She has an improved Clarke compound engine, also shown in an accompanying illustration, with a high pressure piston four inches in diameter, and a low pressure piston eight inches in diameter, the stroke being six inches, and the engine driving two twenty-six inch screws. With 130 pounds of steam, and making 275 revolutions per minute, the launch attains a speed of nine miles per hour, thus fully demonstrating the adaptability of this engine to the successful working of twin screws.
In the Clarke engine, the exhaust pipe from the high pressure cylinder leads to the steam chest of the low pressure cylinder, while the piston in the upper cylinder is secured on a piston rod extending downward and connected with a piston operating in the lower cylinder, the exhaust pipe from the latter leading to the outside. On the piston rod common to both cylinders is secured a crosshead pivotally connected by two pitmen with opposite crank arms on crank shafts mounted to turn in suitable bearings on the base, which also supports a frame carrying the low pressure cylinder, on top of which is a frame supporting the high pressure cylinder. The valves in the two steam chests are connected with each other by a valve rod connected at its lower end in the usual manner with the reversing link, operated from eccentrics secured on one of the crank shafts.
The crank arms stand at angles to each other, so that the crank shafts are turned in opposite directions, and the position of the link is such that it can be readily changed by the reversing lever to simultaneously reverse the motion of the crank shafts. On the crank shafts are also formed two other crank arms pivotally connected by opposite pitmen with a slide mounted in vertical guideways, supported on a frame erected on the base, the motion of the crank shafts causing the vertical sliding motion of the slide traveling loosely in the guideways, and thus serving as a governor, as, in case one of the propellers becomes disabled, the power of the shaft carrying the disabled propeller is directly transferred to the other shaft through the crank arms, pitmen, and slide, and the other propeller is caused to do all the work. All the parts of the engine are within easy reach of the engineer, and there are so few working parts in motion that the friction is reduced to a minimum.
It is said that the plan of construction and the operation of this engine have been carefully observed by practical engineers, and that, considering the dimensions of the boat, her speed, the smallness of the power, the ease with which she passes the centers, the absence of vibration while running, and the very few working parts in motion, the engine is a notable success. She can be run at a very high velocity without injury or risk, and is designed to be very economical in cost and in weight and space. This engine has been recently patented in the United States and foreign countries by Mr. James A. Clarke, of New Westminster.
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IMPROVEMENTS IN THE CONSTRUCTION OF RIVER AND CANAL BARGES.
By M. RITTER (KNIGHT) VON SZABEL, late Austrian Naval Officer, of Vienna.
This innovation consists essentially in an arrangement by which two distinct vessels, on being revolved round their longitudinal axis to an angle of 90 deg., can be combined into one single duplex vessel, or, to put it in different words, a larger vessel is arranged so that it can be parted into two halves (called "semi-barges"), which can be used and navigated with equal facility as two distinct vessels, as if combined into one. By the combination of the two semi-barges into one duplex barge the draught of the vessel is nearly doubled, the ratio existing between the draught of a loaded semi-vessel and the equally loaded duplex vessels being 5:8 (up to 8.5)
The advantage of the invention consists:
1. In this difference of draught.
2. In the smaller width of the semi-vessel as compared with the duplex vessel.
3. In the fact that the combination and separation of the vessels can be effected, without the least disturbance of the cargo, in a minimum of time.
It facilitates the utilization, to the highest possible extent, of the varying conditions and dimensions of canal locks and rivers.
The transition from rivers to canals, and from larger canals to smaller ones, is expedited by the possibility afforded of, on the arrival at the locks, dividing the vessel in a space of a few minutes; of passing with the semi-vessel, singly, the various smaller locks or the shallow canal, after which the two sections may be re-combined and navigated again as one vessel. The process of "folding up" the two vessels will of course take longer than that of separation.
On rivers, the channels of which are interrupted by sand banks and rapids, the same operation may be carried out, thus avoiding the expense and delay necessitated by, perhaps, repeated "lightering," i.e., reduction of the cargo.
Thus, the through traffic on large rivers like the Danube, with its repeated obstacles to navigation, such as the "iron gate," and several sand-banks known and dreaded by bargemen, would be materially facilitated, any necessity for unloading part of the cargo being obviated; moreover, such a duplex vessel composed of two semi-vessels affords the advantage of utilizing to a fuller degree the power of traction, and one large vessel will be more convenient for traffic than two smaller ones.
Further, the mode of construction of the semi-vessels—both ends of which are of a similar pattern—allows of their being navigated up and down a water channel without the necessity of turning them round; provision having also been made for the fixing of the rudder at either end, which would therefore merely require exchanging. This is of some advantage in narrow river beds and canals, and applies equally to the duplex vessel as to the single semi-vessels.
Each semi-barge on its part is also constructed of two equal halves—which are, however, inseparable—and as there is no distinct stem or stern, any one of these semi-vessels will fit any other semi-vessels of the same dimensions, and can be attached to the same by means of the coupling apparatus, and the two "folded up" into one duplex vessel. This process does not present any material difficulties. The two single boats on being coupled together can be made to lean over toward each other, by filling their lateral water compartments, to such an extent that the further closing up can be easily effected by means of specially constructed windlasses. In the case of petroleum vessels the "folding up" operation is facilitated by the circumstance that the petroleum may be made to serve the purposes of water ballast.
As regards the size and tonnage of the new vessels, this will of course depend on the local condition of the rivers and canals to be navigated. Thus a vessel destined for traffic on canals with locks of varying dimensions will have to be adapted to the dimensions of the smallest existing lock.
Supposing the size of the latter to be such as found in the case of the Rhine-Marne or the Rhine-Rhone Canal, or on the Neckar down to Cannstadt, or in the Danube-Main Canal and some smaller canals in the Weser district, etc., viz.:
Length of lock 34.5 meters. Width 5.2 " Depth 1.6 to 2.0 meters.
The semi-barge may be made 32 meters in length, 4 meters in breadth and 2.5 meters total depth, and with a draught of 1.5 meters will be capable of carrying a load of 100 tons (of 1,000 kilos each). Correspondingly the duplex vessel will be able to carry 200 tons, with a minimum draught of 2.4 meters and a width of 5.4 meters, but, with a favorable height of the water level, the draught of the semi-barge may be increased to 1.65 and that of duplex vessels to 2.7 meters.
Where not limited to certain proportions by the dimensions of the locks to be passed, the vessel may in the first place be made longer; the width and height may also be increased accordingly (provided that the proportion of breadth to width is kept within the ratio 4:2.5), so that the semi-barges may be constructed for a single burden up to 300 tons, or 600 for the duplex vessel.
As regards the nature of the cargo, parcels would not be admissible in this instance, but any kind of homogeneous cargo would be suitable which would bear laying over on one side.
Thus this style of vessel would be well adapted for petroleum tank vessels, for the transport of all kinds of cereals, flour, coffee, and sugar in sacks—these latter being held in position by an arrangement of planking and boards so as to prevent any overturning of the goods on the vessels being folded up or taken apart. Similarly in the case of a cargo of loose grain or other loose produce, the same must be prevented from being upset by a kind of wooden casing.
Two semi-vessels loaded with different cargoes may be coupled together, provided that there is not too much difference between their respective draughts. Slight differences may be balanced by the water compartments being filled to a greater or smaller extent.
The peculiar position of the hatches allows of loading the semi-vessels separately as well as when coupled together.
If there is for the time being no necessity for using the vessels in their capacity of separate and duplex barges, any kind of cargo might be loaded that does not require large hatches.
The vessels, on account of their more complicated construction, will be somewhat more expensive, but wherever the advantage offered by them outweighs the extra expenditure, they can be used with success.
The innovation might be of particular importance where a new canal system is being constructed, since the latter might be subdivided into main canals and branch canals—similarly as in the case of ordinary and narrow gauge railways—the main canal being built of a larger section and with larger locks to suit the duplex barges, while the branch canals could be planned of smaller dimensions calculated to suit the semi-barge. Thus the first cost of such a canal system would be materially reduced as compared with a canal installation of one uniform section throughout.
Likewise in mountainous districts with rock soil it would be an important consideration whether a canal had to be blasted out of the solid rock or a tunnel cut, in dimensions suitable for a vessel of 6 or of 14 square meters section below the water line.
In this case, even in certain portions of a main canal—where rendered desirable by the rocky nature of the ground—a smaller section might be adopted, which would only be large enough for single semi-barges, so that the duplex vessel would in these instances have to be taken apart in the same way as in a branch canal.
The saving to be effected by constructing a canal on this principle, as compared with a canal of one uniform section throughout, must be considerable, and the advantages of the arrangement are apparent.
The appended figures will further illustrate the arrangement. Fig. 1 shows two separate semi-barges ready to pursue their journey independently. Fig. 2 shows two semi-barges coupled together ready to be "folded up" by means of ropes and specially constructed windlasses—their lateral water compartments having previously been filled. Fig. 3 shows the duplex vessel after the "folding up" operation just described; and Figs. 4 and 5 show the cross section of two loaded semi-barges as outlined in Figs. 2 and 3.
These Figs. 4 and 5 will also serve to illustrate the manner in which sacks and loose produce should be loaded. Fig. 4 also shows the filled water compartments, and the effect of their weight in making the boats lean toward each other.
The materials most suited for this new style of vessel will be iron and steel such as generally used in the construction of canal and river vessels.
The new ship can be moved by any motor or driving implement, nor could there technically a great difficulty be found for making the boilers move on a quadrant-like rail base in the shape of a circle segment's quarter, or for building a double screw steamer by combining two single screw propellers.
May be a ship owner is willing to submit the innovations to an attempt, so much the more as there is running no great risk by doing so; for in case the ships should not answer the expectations, both separable as well as joinable, they can be used like single ships, without any further alteration being made, except as to the loading gaps.
The above invention is covered by United States patent No. 435,107. Any further information may be had by addressing M. v. Szabel, ix Bezirk, Beethovengasse 10, Wien, Austria.
* * * * *
WELDON'S RANGE FINDER.
Colonel Weldon has recently considerably modified and improved his ingenious range finder, and we illustrate herewith from Engineering the form in which it is now manufactured. It consists of a metal box, the lid of which is shown open in the engraving, and on this lid are fitted three prisms which are the essential constituents of the instrument. When the lid is closed, these, with the compass and level, also attached to the lid, lie inside the metal box, and are thus thoroughly protected. The upper prism marked 1 is a right-angled one and is mounted with the right angle outward; looking into the left-hand corner of this prism one will see in it, by double reflection, objects lying on one's right hand. Below this is a second prism with a principal angle of 88 deg. 51 min. 15 sec., and below this a third with a principal angle of 74 deg. 53 min. 15 sec.
A level and a compass are also mounted on the lid as shown. To use the instrument the observer stands so that the object the range of which is required lies on his right hand, and looking into the left-hand corner of the upper prism views it there by double reflection from the internal faces of the prism. At the same time looking through the opening shown in the lid below the prism he selects some object, which appears nearly in line with the image seen in the prism. He then shifts his position till these two images coincide, in which case lines joining him with the two objects will make right angles with each other. In Fig. 2, O is the object whose range is required, D the object seen by direct vision, and A the position of the observer. The observer now marks his position on the ground, and shifting the instrument looks into the left-hand corner of the second prism, when he again sees the image of the object, whose range is required, by double reflection, but lying now to the right of the object, D. He then retires, keeping in line with A and D, till he reaches B, when the two images again coincide; the lines joining them and the observer now make an angle of 88 deg. 51 min. 15 sec. Then in the triangle, OBA, OA = tan 88 deg. 51 min. 15 sec. X A B = 50 AB. The length AB is easily paced, and the distance OA is 50 times this length.
A longer base, and probably greater accuracy, can be obtained by using the second prism only, as indicated in Fig. 3, in which case the distance of the object is 25 times the distance BC. This second prism is, however, best adapted for predicting the range of moving objects. Three observers are required. Two of them have finders, while the other measures the distance between the two. The first two observers separate, and No. 2 takes a position such that the object is reflected to one side of observer No. 1, whom he views by direct vision. As the object continues to move, its image gets nearer and nearer No. 1, who during the whole of the time moves a little to one side or the other, so as to keep the image of the object constantly in line with No. 2. Just as the image of the object gets very near No. 1, No. 2 calls out "Ready," the distance between the two observers is taken by the third, and when the image of the object actually falls on No. 1 its distance is just 25 times the distance between them, and the guns set to this range are fired by word of command from No. 2.
By using the third prism in conjunction with the second a still longer base of one-fourth the distance of the object can be employed. The range finder can also be used as a depleidoscope for transit observations. For this purpose it is mounted on a block of wood by means of elastic band and leveled by the level on its lid, being at the same time set in the meridian of the place. The lid is opened to make an angle with the horizon equal to the latitude of the place of observation. On looking into the upper prism two images of the sun will be seen on each side of the apex of the prism, which gradually approach each other as the sun nears the meridian, and finally coincide as it passes it, the time of which being noted gives the longitude of the place.
Extensive trials of the instrument have been made both in this country and in India, which agree in showing that the average error in using the instrument is about 21/2 to 31/2 per cent.
* * * * *
WHEELS LINKED WITH A BELL CRANK.
There are four ways in which a connecting rod is made use of in machine work. The first is in linking two wheels together that stand in the same position, but a slight distance off centers. The rod in this case has only to lead the driven wheel around by connecting it with the driver, and consequently has only to endure a pulling strain in the direction of its length. The second is when the rod is called upon to stand a pull and a push at every revolution. The third takes in the matter of the twisting strain that a rod can manage; but the fourth brings the hardest usage that a connecting rod can be called upon to endure, and that is by making a lever of the rod to get a driving action by prying on a fulcrum in the center. In Fig. 1 is seen a case of this kind taken from a machine in which a disk engine was made use of. The rod has a chance to turn about on its center from a ball and socket joint, and engages with both wheels in nicely fitted journals, and boxes set in line with the center of the socket joint, so that when one wheel turns, the rod pries the other around by using the rod as a lever and the ball joint for a fulcrum, giving a uniform leverage all the while, with no dead centers.
To set this arrangement around at right angles, or where the shafts will bring the wheels together, as for bevel gears, a bent lever arm would need to be used, as shown in Fig. 2, but the bend in the connecting arms brings in another feature that must be provided, as it allows the wheels to turn either with or against each other, and leaves two places where the bent arms will come to a dead center. What is needed here is another element that will take all the twisting strain on the rod and keep the pitch of both arms alike in every portion of a revolution. To do this the ball and socket joint will need to be replaced by a gambrel joint like a ship's compass, and arranging the bent driving arms as shown in Fig. 3; then the driving end of the connecting frame will move about in a true circle, producing as great a tendency to turn the driving wheel in one position as another. In this arrangement there must be at least six nicely fitted journals and their bearings, four of which will be required to take care of the forked connecting rod that joins the wheels together. Besides all this the bearings must all line up with the same center that the shafts are centered from or there will be a "pinch" somewhere in the system. It may seem at first that there must be more or less end-on movement provided for, and that the bearings should be spherical; but that it is not the case will be noticed when all the points are understood to be working from one center similar to that provided for in bevel gears.—Boston Journal of Commerce.
* * * * *
THE DECORATIVE TREATMENT OF NATURAL FOLIAGE.[1]
[Footnote 1: Lectures before the Society of Arts, London, 1891.]
By HUGH STANNUS.
Lecture I.
Sec. 1.—THE ELEMENTS OF DECORATION.
The chief impelling Motives which have caused that treatment of objects which is now termed Decorative, have been:
(a) That necessitated by the Usage, which is FUNCTIONAL;
(b) That resulting from the Instinct to please the eye, which is AESTHETIC;
(c) That arising from the Desire to record or to teach, which is the DIDACTIC motive;
The AESTHETIC instinct of the early peoples was gratified by:
(a) The forms of their weapons or tools;
(b) The patterns with which they are decorated;
(c) The imitation of the surrounding animals, e.g. the Deer scratched on the horn at the British Museum.
Imitation was afterward applied to the vegetable creation; and much of what is termed Ornament was derived from that class of elements.
The ELEMENTS OF DECORATION are the material used by the Artist. They might be considered to include everything that is visible; but since Decoration is a result of the aesthetic instinct, the field is narrowed to such as are pleasing at the first glance. And the selection is further limited to such as are suitable to the shape and size of objects.
They may be classified according to their relative Dignity, as follows:
The Human form, Animal forms, Natural foliage, Artificial objects, Artificial foliage, and Geometrical figures.
Sec. 2.—THE TWO KINDS OF FOLIAGE.
A Distinction is made between natural and artificial foliage. They have much in common; and consequently many have supposed that our Western artificial foliage is merely a very-much-conventionalized version of natural foliage. The supposition is correct with regard to Eastern Pattern work, but not in Western Architectural ornamentation.
A simple generalization may make this clear. The ordinary stock foliage of the Ornamentist was evolved in connection with:
(In the West) (In the East) ARCHITECTURE, TEXTILES, as in Greece. as in Persia.
Hence the primary Elements of decoration were derived from:
(In the West) (In the East) GEOMETRICAL LINES, NATURAL FLOWERS and LEAVES, e.g. the meander, spiral, etc. e.g. the pine, pomegranate, etc.
Further, it may be observed that the Method of treating these Elements has been different:
(In the West) (In the East) The Geometrical lines The natural foliage was were enriched by the introduction codified by the introduction of the details of of Geometrical arrangement; Natural vegetation; thus thus becoming becoming gradually more gradually more naturalesque. artificial.
An APPROXIMATION between the two treatments, sometimes appears; but the two kinds—Artificial, and Natural—are essentially different in origin; and should be kept distinct in their application.
This approximation may be shown, in a tabular arrangement, thus:
GEOMETRY...........................................................NATURE
The patterns are merely The plants are copied as straight lines, dots, and accurately as possible. portions of circles.
The lines become stems. The plant is applied without repetition.
Leaves are added to the Repetition is used with the stems. plants.
Serration is added to the Weaving economy induces leaf-edge. symmetry.
Similarity of serrated Symmetry induces Geometrical leaf-edge to the Akanthos Severity, and the Omission plant, is observed; of all details of the Imitation becomes more original plant which are not direct; and this artificial easily worked in connection foliage becomes termed with geometrical "Acanthus." arrangement.
Flowers generally circular The Flowers and Leaves in mass-shape, are added (only) survive; the growth at the ends of the spiral of the stems is forgotten; stems. and tradition does the rest.
Sec. 3.—APPLICATION OF THE TWO KINDS.
Each of these two kinds of foliage has its own proper use. Artificial foliage is appropriate to the enrichment of Architecture; and Natural foliage to those objects which are not architectural, but are termed "movables," including under this term, Furniture, and more especially Hangings and other applications of the Textile art.
This may be seen on comparing the two columns below, of which the L.H. one refers to Architecture, and the R.H. one to Natural foliage.
(Architecture) (Natural foliage) RULES: Governed by severe Exhibits apparent playful rules of Repetition, Freedom. There are Axiality, Symmetry, etc., underlying Rules, which which are apparent to are detected by the scientific the passer-by. Hence Botanist; but these Artificial foliage, being are not seen by the casual regular in its structure, observer. is more appropriate than the (apparently) irregular growth of Natural foliage. CHARACTERISTICS: Rigidity and Stability. Elasticity and Tremulousness in every breeze.
LINES OF COMPOSITION: Geometrical lines. In determinate curves, The geometrical lines which are very subtile, and spirals of Artificial and varied, and therefore foliage demand an unmoving suitable to a hanging and surface for proper view. swaying material.
The curves of Nature They would generally be spoiled are not spoiled when on a if not on a plane surface. folded material.
DISTRIBUTION: Symmetrical. The Balanced. The growth symmetry of artificial of natural foliage is generally foliage is appropriate to symmetrical; but that of Architecture. this is not apparent.
BEAUTY: Depends on form, with More appropriate to objects color as a secondary adjunct. which depend on color for their principal charm.
There have been waves of the desire to introduce Natural foliage into Architecture (e.g. in the "Decorated period" of Gothic architecture); but the Artificial elements have always proved too strong, and the two have never mixed. In Architecture, everything has three dimensions; and the artificial foliage is carved with leaves, etc., of a suitable thickness: in Natural foliage the tenuity of leaves, etc., is such that it cannot be reproduced. Even in the architraves round the glorious doors of Florence the natural foliage is not always a success; and where Ghiberti has stopped short in the ductile bronze, it is not probable that the modern carver will succeed in stone. It may therefore be suggested that the close imitation of Natural foliage should be confined to objects of two dimensions, i.e., to plane surfaces and figured materials.
This selection of the Elements of Decoration, according to their association, is analogous to the selection made use of by the Poet, from the words and ideas, which are his Materials. It will be observed that, as on a Classic or Heroic subject, the choice is of learned words and classical ideas, and on a Domestic or Pastoral one, simple words and homely similes are used—so, in conjunction with the severe forms of Architecture, the formal character of artificial foliage is suitable; and for decorating Textiles and other movable Accessories, the Natural foliage, with which the earth is clothed and beautified, is appropriate.
ENRICHMENT OF SURFACE may be beautiful for one reason; IMITATION OF NATURE is beautiful for another. When imitations of natural foliage are introduced decoratively on a surface, then may it be twice beautiful—first, in the principles according to which the distribution is arranged; and secondly, because of the elements which are worked in being beautiful in themselves. Geometrical elements might be so used as to serve the first end, but can never fulfill the second: Storiation fulfills the second; but its increase of interest absorbs the first.
This course of Lectures is intended to treat of Natural foliage, leaving Artificial foliage to be dealt with at another opportunity. It is not Historical. The History of the Decorative treatment of Natural foliage, showing its evolution in the past, is a large and interesting theme; but, unless this were accompanied by critical remarks based on given principles, the method might be barren of results. Tradition is not to be undervalued; but the student should be led to Tradition through Principles.
It is further intended more especially to apply to the aesthetic use. When natural foliage is used AEsthetically (i.e., decoratively), then the Shape of the surface should govern the Mass shape of the foliage, and there should be Parallelism between them (see Sec. 29). When used Didactically (i.e., symbolically), then the foliage may be treated more freely.
Sec. 4.—THE FOUR TREATMENTS.
There are, broadly speaking, four methods of treating Natural foliage. These may be arranged in a Chart, according to their relation to the two poles of Art and Science; from Realism (which is all Art and no Science) to the "Botanical Analysis" method (in which is a little Science but no Art), thus:
The first two of these methods are Artistic and legitimate: the others are inartistic and misleading. Before treating of the artistic methods it will be well to clear the ground by dismissing the others.
ART POLE..........................................SCIENCE POLE
Realism Conventionalism Disguised Botanical (See Sec. 10). (See Sec. 14). Artificialism Analysis (See Sec. 6). (See Sec. 5).
Sec. 5.—THE BOTANICAL ANALYSIS TREATMENT.
In this method the student was taught (i) to draw each plant with the Stem straightened out, the Leaves flattened out, and the Flowers represented as in side elevation or plan. (ii) The Flowers were further pulled in pieces, and the Petals were flattened out in a manner similar to the Entomologists' practice of displaying their "specimens" scientifically. Often, also (iii) the Stems and Buds were cut through; and "patterns" were made with the Sections.
With regard to the first of these practices (i): it should be observed that much of the beauty of appearance of natural foliage results from the variety of view, the subtile curvature, and the foreshortening, as seen in perspective; and that to sacrifice all these for the sake of a diagram would be a wasted opportunity.
With regard to the other practices (ii) and (iii): it is obvious that these statements of the facts of the plant are useful as a part of the Science of Botany; but can no more be considered as making Decoration than Anatomical diagrams can be looked upon as Pictures. Some knowledge of external Botany is useful to a Pattern artist as some knowledge of external Anatomy is useful to the Pictorial artist. In each of these cases, the Science, which discovers and records facts, is subservient to its sister, Art, which uses the facts to interpret appearances; and, when scientific diagrams are put forth as Art, the Science is in its wrong place: it has then been treated as if it were the Building instead of being only the Scaffolding; and the results of such attempts cannot be considered as complete or final.
Examples of this method are given in Figs. 1 and 2. It was officially encouraged about twenty-five years ago; and books like "Plants, their Natural Growth and Ornamental Treatment," and "Suggestions in Floral Design," both by F. Edward Hulme, F.L.S., etc., show it at its best.
In criticising this method, there is no desire to cast any slight upon those who were responsible for it. They were groping in the dark, and did the best they knew, according to their lights. But Japanese work was not known at that time, and, but for that, the Pattern artist of to-day might still be occupied in pinning leaves and flowers against the wall. It was, moreover, a protest against the Cabbage Rose on the Hearth rug, that some may still remember with shuddering.
Sec. 6.—THE DISGUISED ARTIFICIALITY TREATMENT.
In this method the student was taught to sketch out what he considered to be good Curves and Spirals; and then (i) to bend the selected plant so that its stem might coincide with them, regardless of its own proper natural growth; or (ii) to deck out the first drawn spirals with the leaves and flowers of the selected plant.
With regard to the first of these practices: it is much more foolish than the Analysis method; and is little short of blasphemy against the Great Designer. He has determined how each plant shall grow: how, within limits of cultivation, its stems and branches shall separate, each to seek its own share of air and sunshine; how its leaves shall stand erect or droop, each according to its function; and always in perfect beauty. And further: how each family of plants shall have its own method of branching; which is as much a part of its character and often of its beauty as are the Flowers and Leaves.
The second practice, which generally produces a result similar to the first, is quite as unthinking. It is more often practiced; and is responsible for many of the labored and uninteresting designs which are common. If the Pattern-artist deck-out the old worn-out and common place spirals with leaves and flowers borrowed from Nature—the result is like the "voice of Jacob and the hands of Esau;" it is merely a Disguise of Artificiality.
An example of this method is given in Fig. 3. It was generally practiced in Germany; and books like "Das Vegetabile Ornamente," by K. Krumbholz, show it at its best.
If this treatment were universally followed—there would soon be an end to design with natural foliage. The spectator might observe one border which appeared to be a Rose, another a Tulip, the third a Thistle, and the fourth a Fuchsia; and, on examination, discover that these were not Rose, Tulip, Thistle, and Fuchsia; but merely that very artificial old friend—the Spiral-scroll—in disguise.
An apologist for this method remarks:—" ... In such matters as the ramification of plants, ... nature is always making angles and elbows [sic] which we are obliged, in decorative treatment, to change into curves for our purpose;...". This opinion needs only to be applied to animals in order to exhibit its absurdity; and with regard to plants, it will be seen that this tampering has not even the poor merit of success.
Sec. 7.—NOTE ON SYMMETRY.
A desire for Symmetry often accompanies these two treatments. This is a quality to be avoided whenever possible in Natural foliage design. The so-called "Turn-over patterns" are an economy in Weaving-design, but the economy is of the wrong kind. An artist should spend his thought to spare material or cost in working. When he spares his thought—making the least amount of thought cover the greatest amount of surface—then is his work worth to the world just what it has cost him, i.e., very little.
So injurious is the influence of Symmetry in Natural foliage design, that it might almost be a test question—"Is the design symmetrical?" When the exigencies of Machine-reproduction necessitate this with Natural foliage—it is a hardship which the Artist regretfully accepts, and no one would willingly make a design for Hand-reproduction which was symmetrical; rather would he spend himself to insure the worthier result which ensues from Balance.
An example of Symmetry is given in Fig. 4; and of Balance in Fig. 5. Each panel contains two classes of Elements:—Natural foliage (i.e., two branches of the Bay tree), and an Artificial object (i.e., a Ribbon which ties them). The lower Element (i.e., the Ribbon) is treated symmetrically in both panels: the higher Element (i.e., the Branches) are symmetrical in the former panel, and balanced in the latter. This latter treatment, will be seen to be not only the more interesting, but the more like the infinite variety of Nature; while the former is a wasted opportunity, and contrary to Nature.
The Student will observe by experience that the mind soon tires of Artificiality, both in Curvature and in Symmetry; the lines of Nature have a pleasant freshness and inexhaustible variety; and the Natural method of treating Nature is not only the most true, but also the most beautiful.
Sec. 8.—REALISM AND CONVENTIONALISM: DEFINITIONS.
REALISM—the result of Realistic treatment, i.e., the attempt to render the reproduction as like the reality as is possible, even to the verge of deception—is the aim of the Pictorial-Artist. In Pictures the surface appears to have been annihilated, and the spectator beholds the scene as if there were a hole through the wall. It is not the highest, and should not be the only aim in Art; but it has always been sought for and admired. It requires perfect conditions, of materials and tools; i.e., complete Technical appliances.
CONVENTIONALISM—the result of incomplete Technical appliances, and the attempt to render so much of the Beauty of the original as is possible, with due regard to their capabilities—is the aim of the Decorative-Artist. It is not the highest aim; though a necessary curb in Decorative-Art, both for the technical reason, and also as a result of the Position or Function of the object.
It will thus be seen that the two words, when used with regard to foliage of any kind, refer to the Method of representing it, and not to its Kind or its manner of Growth.
Sec. 9.—SCALES FROM REALISM TO CONVENTIONALISM.
These two methods, when applied absolutely, form the two extremes:—The most complete REALISM being at one end, and the most limited CONVENTIONALISM at the other. There are scales of gradual reduction between them, which may be shown on two charts:
(i) Reduction in the NUMBER OF PARTS which preserve their Realistic rendering.
(ii) Reduction in the DEGREE OF REALISM through all parts.
(i) According to the number of the features or parts of the design which are treated with less than realism. Thus there might be a panel representing a Window-opening with an architectural framing, with a Flower-vase on the sill, and a Landscape-background. The first part to be reduced in realistic rendering would be the Background, the second would be the Framing, leaving the third, the Flower-vase, as the survival. This is a Scale of reduction in Number of Parts.
It may be shown, in tabular arrangement, thus:—
REALISM............................................CONVENTIONALISM.
COMPLETE PICTORIAL REALISM, in which all parts are realistically represented (see Sec. 10).
SEMI-PICTORIAL REALISM, in which the Back-ground is reduced to a flat-tint, while all the remaining parts are realistically represented (see Sec. 11).
DECORATIVE REALISM, in which the chief Feature (only) is realistically represented, and all the other parts are reduced to conventional renderings (see Sec. 12).
COMPLETE CONVENTIONALISM, in which all parts are reduced to conventional renderings (see Conventionalism).
Inasmuch as there is some realistic part remaining in each of the first three methods—these are classified under the heading of REALISM.
(ii) According to the Degree in which color, gradation, or shading, is sacrificed, in consequence of the limited Means at the disposal of the Artist; resulting in the gradual departure from Realism to the most severe Conventionalism. The reduction is applied to all parts of the work. This is a scale of reduction in Degree. There are two Varieties in each degree; and they are marked with italic letters.
It may be shown, in tabular arrangement, thus:—
REALISM.............................................CONVENTIONALISM.
COMPLETE REALISM, in which all parts are represented, in proper colors, and perfect gradation, with correct light and shade (see Sec. 10).
FIRST DEGREE OF CONVENTIONALISM, in which all parts are represented: (a) By a reduced number of Pigments, the other qualities remaining; (b) By reduction in gradation and shading to Flat-tints of several pigments (see Sec. 15).
SECOND DEGREE OF CONVENTIONALISM, in which all parts are represented: (c) By a reduction to Monochrome of color, with Gradation (only) remaining; (d) By reduction to Monochrome of White and Black, with Gradation (only) remaining (see Sec. 16).
THIRD DEGREE OF CONVENTIONALISM, in which all parts are represented: (e) By reduction to a Flat-tint of one pigment on a ground of another; (f) By reduction to a Flat-tint of White on Black, or vice versa (see Sec. 17).
ULTIMATE CONVENTIONALISM, in which all parts are represented; (g) By reduction to Outline of several pigments; (h) Reduction to Outline of one pigment (see Sec.18).
Inasmuch as Realism ceases so soon as any reduction in the three qualities (of color, gradation, and shadow) is introduced; and the treatment becomes more Conventional in each method after the first—these are classified under the heading of CONVENTIONALISM.
[There is an analogous scale of reduction in Form, from the Complete-relief of an isolated Statue to the Flatness of a Floor-plate; but this does not belong to the present subject.]
* * * * *
THE CYCLOSTAT.
The various processes commonly employed for the observation of bodies in motion (intermittent light or vision) greatly fatigue the observer, and, as a general thing, give only images, that are difficult to examine. We are going to show how Prof. Marc Thury, upon making researches in a new direction, has succeeded in constructing an apparatus that permits of the continuous observation of a body having a rapid rotary motion. The principle of the method is of extreme simplicity.
Let us consider (Fig. 1) a mirror, A B, reflecting an object, C D, and revolving around it: when the mirror will have made a half revolution, the image, C' D', of the object will have made an entire one. The figure represents three successive positions of the mirror, distant by an eighth of a revolution. The structure of the image shows that it has made a quarter revolution in an opposite direction in each of its positions. But if (Fig. 2) the body itself has revolved in the same direction with an angular velocity double that of the mirror, its image will have described a circle in remaining constantly parallel with itself. The image will be just as insensible as the object itself; but it is very easy to bring it back to a state of rest.
Let us suppose (Fig. 3a) the observer placed at O, the revolving object at T, the axis of rotation being this time the line O F. Let us place a mirror at A B and cause it to revolve around the same axis; but, instead of looking at the image directly in the mirror, let us receive it, before and after its reflection upon A B, upon two mirrors, C D and D E, inclined 30 deg. upon the axis of rotation of the system; the image, instead of being observed directly in the mirror, A B, will always be seen in the axis, O F, and will consequently appear immovable.
The same result may be obtained (Fig. 3b) with a rectangular isosceles prism whose face, A B, serves as a mirror, while the faces, A C and B D, break the ray—the first deflecting it from the axis to throw it on the mirror, and the second throwing it back to the axis of rotation, which is at the same time the line of direction of the sight.
The principle of the instrument, then, consists in causing the revolution, around the axis of rotation of the object to be observed, of a mirror parallel with such axis, and in observing it in the axis itself after sending the image to it by two reflections or two refractions. In reality, the entire instrument is contained in the small prism above, properly mounted upon a wheel that may be revolved at will; and, in this form, it may serve, for example, to determine the rotary velocity of an inaccessible axis. For this it will suffice to modify its velocity until the axis appears to be at rest, and to apply the revolution counter to the wheel upon which the prism is mounted, or to another wheel controlling the mechanism.
But Mr. Thury has constructed a completer apparatus, the cyclostat (Fig. 4), which, opposite the prism, has a second plate whose actuating wheel is mounted upon the same axis as the first, the gearing being so calculated that the prism shall revolve with twice less velocity than the second plate. This latter, observed through the prism, will be always seen at rest, and be able to serve as a support for the object that it is desired to examine.
The applications are multitudinous. In the first place, in certain difficult cases, it may serve for the observation of a swinging thermometer, which is then read during its motion. Then it may be employed for the continuous observation of a body submitted to centrifugal force. Apropos of this, we desire to add a few words. Most of the forces at our disposal, applied to a body, are transmitted from molecule to molecule, and produce tension, crushing, etc. Gravity and magnetic attraction form an exception; their point of application is found in all the molecules of the body, and they produce pressures and slidings of a peculiar kind. But these forces are of a very limited magnitude; but it might nevertheless be of great interest to amplify them in a strong measure. Let us, for example, suppose that a magician has found a means of increasing the intensity of gravity tenfold in his laboratory. All the conditions of life would be modified to the extent of being unrecognizable. A living being borne in this space would remain small and squat. All objects would be stocky and be spread out in width or else be shattered. Viscid or semi-solid bodies, such as pitch, would rapidly spread out and take on a surface as plane and smooth as water under the conditions of gravity upon the earth. On still further increasing the gravity, we would see the soft metals behaving in the same way, and lead, copper and silver would in turn flow away. These metals, in fact, are perfectly moulded under a strong pressure, just like liquids, through the simple effect of the attraction of the earth applied to all their molecules. Upon causing an adequate attractive force to act upon the molecules of metals they will be placed under conditions analogous to those to which they are submitted in strong presses or in the mills that serve for coining money. The sole difference consists in the fact that the action of gravity is infinitely more regular, and purer, from a physical standpoint, than that of the press or coining mill. Through very simple considerations, we thus reach the principle which was enunciated, we believe, by the illustrious Stokes, that our idea of solid and liquid bodies is a necessary consequence of the intensity of gravity upon the earth. Upon a larger or smaller planet, a certain number of solid bodies would pass to a liquid state, or inversely. Let us return to the cyclostat. In default of gravity, centrifugal force gives us a means of realizing certain conditions that we would find in the laboratory of our magician. The cyclostat permits us to observe what is going on in that laboratory without submitting ourselves to forces that might cause us great annoyance. We have hitherto been content to put poor frogs therein and study upon them the effect of the central anaemia and peripheral congestion produced on their organism by the unrestrained motion of the liquids carried along by centrifugal force. The results, it seems, have proved very curious.—La Nature.
* * * * *
MERCURY WEIGHING MACHINE.
We illustrate herewith a novel type of weighing machine. Hitherto the weighing machines in common use have either been designed with some kind of steelyard apparatus, upon which weights could be moved to different distances from a fixed fulcrum, or springs have been so applied as to be compressed to different degrees by different weights put upon the scale pan, or table, of the machine. In other instances more complicated mechanism is used, and various movable counterpoises are usually required in order to balance the moving parts of the machine.
The type of machine which we now illustrate has been recently brought out by Mr. G.E. Rutter, and the system has given very satisfactory results with platform weighing machines. The engraving illustrates a form of balance which may be applied to strength testing machines, or for any work where an apparatus of the type of a Salter's balance would be of use. It is simple in construction, and consists of a tube A closed at the bottom and forming a reservoir for mercury. The body which it is required to weigh is hung upon the hook B carried by the crossbar C, which is connected by rigid rods to the upper part of the tube, and by means of the internal rods D is attached to the cross head E, which works freely inside the tube A. The top part of the tube is, as will be clearly understood from the illustration, cut away to allow of the descent of the rods. To the cross head E is attached the piston F, which may be made of wood or of a hollow metal tube closed at the end, or other suitable material. It will be easily understood that when a weight is hung upon the hook B, the piston F is caused to descend into the mercury which rises in the annular space between the piston and the tube. The weight of the volume of displaced mercury is proportional to the weight of the body hung upon the hook, and the buoyancy of the piston in the mercury forms the upward force which balances the downward pull of gravity. When the apparatus is at rest the piston F descends into the mercury to such a distance as will balance the weight of the rods, hook, and piston itself. If, now, the cross bar G, provided with a pointer H, be fixed to the rods, it should at that time register zero, upon the scale J fixed to the outside of the tube, and as the descent of the piston into the mercury is directly proportional to the weight of the body attached to the hook B, the divisions of the scale will all be equal. It will thus be seen that the apparatus is extremely simple in theory, and it only remains to construct it in such a form that the mercury may not easily be spilt in moving the instrument from place to place. This is effected by causing the cross head E to fill the tube while working freely therein, and a small valve is arranged to allow for the passage of air. The cross bar G can be regulated upon the rods by means of set screws.—Industries.
* * * * *
REEFING SAILS FROM THE DECK.
While this method may be applied to topsails and top-gallant-sails, I especially apply it to courses, which, being so difficult to reef the old way, may by this method be reefed from the deck in a few minutes.
After several years of trial by myself and others, on voyages around Cape Horn under all circumstances of weather, of sleet and snow, this method has always given the utmost satisfaction.
The average time required for reefing and setting was noted for five years, being seven and one-half minutes.
This trial was made on a mainsail, the yard being seventy-one feet long, and reefyard sixty-six feet long, eleven inches diameter at center and nine at yard-arms.
By reference to the drawing it will be seen that it is not necessary to have clewgarnets or buntlines in reefing. The operation is performed by easing of the sheet and hauling the lee reef-tackle first, also the midship reef tackle.
When the yardarm of the reefspar is up at the lee side, the sail cannot sag to leeward when the tack is eased away. Now haul the weather reef-tackle likewise midship, snug up to the yard, belay all down the tack, and sheet aft.
As all the reef-tackles lead to the slings of the yard, there is no impediment in swinging the yard when the reef-tackles are taut and belayed.
The slack sail will not chafe, as it remains quiet, but if so desired may be stopped up at leisure with only a few hands with stops provided for that purpose.
In case of a sudden squall the sail may be hauled up the usual way. The buntlines will draw the part of the sail below the reef well up on the part above the reefyard, and remain becalmed, while the weight of the reefspar will prevent any slatting or danger of losing the sail any more than any other sail clewed up.
In case there is steam power at hand, all three reef-tackles may be hauled simultaneously, easing sheet and tack sufficiently to let the wind out of the sail without shaking.
There are other advantages gained by this method; while its essentials are positive, quick reefing from the deck in all weathers, it is also better reefed than by the old method. For by this new method the sail is not strained or torn, and the sail will wear longer, not being subject to such straining.
It may be carried longer, as the spar supports the sail like a band, especially an old sail.
This method does not interfere with the use of the so called midship-tack, but change of putting on bands, from the leech of the sail at the reef to the center tack would be necessary.
The weight of the spar may be considered by some as objectionable, (an old argument against double-topsail yards). The spar used for the reef may be about one-half the diameter of the yard on which it is to be used.
Such critics do not consider that a crew of men aloft on the yard are several times heavier than such a spar.
L.K. MORSE.
Rockport, Me., Oct. 28, 1891.
* * * * *
A NEW PROCESS FOR THE BLEACHING OF JUTE.
By Messrs. LEYKAM and TOSEFOTHAL.
Jute is well known as a very cheap fiber, and its employment in textile industry is consequently both extensive and always increasing. Accompanying this increase is a corresponding one in the amount of old waste jute, which can be employed for the manufacture of paper.
Up to the present time, only very little use has been made of jute for the manufacture of thread and the finer fabrics, because the difficulty of bleaching the fiber satisfactorily has proved a very serious hindrance to its improvement by chemical means. All the methods hitherto proposed for bleaching jute are so costly that they can scarcely be made to pay; and, moreover, in many cases, the jute is scarcely bleached, and loses considerably in firmness and weight, owing to the large quantities of bleaching agents which have to be applied.
In consequence of this difficulty, the enormous quantities of jute scraps, which are always available, are utilized in paper making almost entirely for the production of ordinary wrapping paper, which is, at the best, of medium quality. In the well known work of Hoffmann and Muller, the authors refer to the great difficulty of bleaching jute, and therefore recommend that it be not used for making white papers.
Messrs. Leykam and Tosefothal have succeeded in bleaching it, and rendering the fiber perfectly white, by a new process, simple and cheap (which we describe below), so that their method can be very advantageously employed in the paper industry.
The jute fiber only loses very little of its original firmness and weight; but, on the other hand, gains largely in pliability and elasticity, so that the paper made from it is of great strength, and not only resists tearing, but especially crumpling and breaking.
The jute may be submitted to the process in any form whatever, either crude, in scraps, or as thread or tissue.
The material to be bleached is first treated with gaseous chlorine or chlorine water, in order to attack the jute pigment, which is very difficult to bleach, until it takes an orange shade. After having removed the acids, etc., formed by this treatment, the jute is placed in a weak alkaline bath, cold or hot, of caustic soda, caustic potash, caustic ammonia, quicklime, sodium or potassium carbonate, etc., or a mixture of several of these substances, which converts the greatest part of the jute pigment, already altered by the chlorine, into a form easily soluble in water, so that the pigment can be readily removed by a washing with water. After this washing the jute can be bleached as easily as any other vegetable fiber in the ordinary manner, by means of bleaching powder, etc., and an excellent fibrous material is obtained, which can be made use of with advantage in the textile and paper industries. |
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