Chapter IV: Front Matter (4)

Professor Dewar, who was born in Kincardine-on-Forth in 1842, was educated at the University of Edinburgh, where his natural and special gifts as a chemist were developed by Sir Lyon Playfair, at that time Professor of Chemistry in the university. The perspicacity and tenacity of purpose which are characteristic of so many Scotchmen were eminently the inheritance of Sir Lyon’s young assistant, and between that period and the present a long series of original investigations in all departments of chemistry have won for Professor Dewar at his prime the Jacksonian Professorship of Natural Experimental Philosophy at Cambridge University, the Fullerian Professorship of Chemistry at the Royal Institution, the Fellowship of the Royal Society, the degree of Doctor of Laws, and other dignities, which make great alphabetical richness after his name upon scientific occasions of state. Personally, he is of middle height and strong build, with a clearly cut face, full of character. His speech, faintly flavored with the accent of Scotia, is exact and emphatic; and his manner, whether he is concentrated upon a scientific demonstration in his laboratory or traversing the speculative questions of the hour in ordinary conversation in his drawing-room, has the earnestness of the profound scientist, very agreeably tempered by the polish of the traveller and cosmopolitan man of the world. His absorption in scientific pursuits has not denied him a very marked esthetic development, and his residential suite of apartments at the Royal Institution is filled with treasures, rare tapestries, bronzes, and carvings, picked up at continental dépôts or purchased at the sales of great collections, which would make a highly interesting article in themselves. To her husband’s scientific sense of the value of age in wines, Mrs. Dewar adds her original researches in the matter of choice teas, and it is averred by the eminent membership of the Royal Institution that the degree of domestic civilization which prevails on the third floor of the building is quite as high and more potentially attractive than the stage of scientific civilization which rules in the theatre, the libraries, and the laboratories of the floors below. Like most Scotchmen, however, Professor Dewar is simple in his tastes, and is more deeply stirred by a frozen gas or an antique bronze than anything in the way of bisques or _suprêmes_. His heart, which shows no signs of low temperature, is mainly in his laboratory, and he leads the way there, down a flight of stone steps to the basement, with a readiness that very clearly exhibits his latent enthusiasm.

Moreover, it is a laboratory eminently calculated to excite the enthusiasm of anybody, being, in fact, the most famous laboratory known to chemical science. The workshop of Sir Humphry Davy, Michael Faraday, and Doctor Thomas Young, to say nothing of lesser and still famous men, it is a nest in which more great discoveries have been hatched than any other of its kind on earth. Here it was that Young conducted the experiments which gave us the undulatory theory of light. Here Davy, covering, nearly a hundred years ago, almost the whole field of chemistry and electricity, made clear those principles which science and applied science since his time have developed to the marvellous degrees of to-day. A little room leading to the right of the main laboratory was the scene of all Faraday’s experiments in magnetism, and a cellar on its south side is known to this day as “Davy’s Froggery,” from the fact that Davy kept in it hundreds of live frogs for use in his experiments. Professor Dewar, whose sense of the inspiration of his surroundings is clearly deep, dwells upon them with interest, and tells how on one occasion a barrel of live frogs, imported by Davy from France, burst at the docks, causing astonishment there and consternation in the laboratory when Davy learned of his loss. It was in this laboratory that Faraday first liquefied chlorine gas, sending thereupon that famously curt note to Dr. Paris, the biographer of Davy, in 1823:

“DEAR SIR:--The oil you noticed yesterday turns out to be
liquid chlorine.

“Yours faithfully,

“MICHAEL FARADAY.”

All of Faraday’s work in the liquefaction of gases, the discovery of new hydrocarbons, the study of the changes of steel through the slight admixture of other metals, the improvement of optical glass, and the long list of results which are to-day represented in millions of tons of products from thousands of factories, were obtained within these four walls. And nothing could better illustrate the earnestness and modesty of the great chemist than a little anecdote which Professor Dewar, standing in the centre of the room, calls to mind. “I never met Faraday,” says he, “but Tyndall told me this story of him. The first time Tyndall entered this laboratory, Faraday led him to this point and said: ‘Tyndall, this is a sacred spot. This is the spot on which Davy separated sodium and potassium.’”

The laboratory of to-day, however, looks very little like a scene of chemical industry. It has more the air of a machine shop, equipped with power and mechanical appliances of a very heavy kind. Instead of bottles and multi-colored liquids, all is metal and steam. The room is about thirty feet wide and fifty deep, the north front consisting entirely of glass windows opening on a well-lighted interior court. In the left-hand corner, at the back, is a large steam-engine, while a smaller one occupies the corner diagonally across. Shafts, wheels, and belting run to two large air-pumps and three steel compressors, each about the size and shape of a small travelling trunk, and used respectively for compressing oxygen, nitrous oxide, and ethylene. A fourth compressor, or double compressing chamber, is cylindrical in form, and is wrapped in thick white flannel. This is the source of the liquefied oxygen. The system which Professor Dewar has followed is not novel in its general principles, as he explains. Specifically, however, it contains many new inventions which he does not wish made public. They are mainly in the nature of stop-cocks and valves, which it took long study to invent, and which became perfect only after many failures and costly experiments. To liquefy oxygen, he simply used pressure at low temperatures; but as, up to 1878, both oxygen and nitrogen after repeated trials were looked upon as permanent gases, it may be imagined that the attainment of temperatures low enough was a problem which required an extraordinary command of mechanics as well as of chemistry to practically solve.

“The process of liquefying oxygen, briefly speaking,” says the professor, “is this. Into the outer chamber of that double compressor I introduce, through a pipe, liquid nitrous oxide gas, under a pressure of about 1,400 pounds to the square inch. I then allow it to evaporate rapidly, and thus obtain a temperature around the inner chamber of −90° C. (−130° F.). Into this cooled inner chamber I introduce liquid ethylene, which is a gas at ordinary temperatures, under a pressure of 1,800 pounds to the square inch. When the inner chamber is full of ethylene, its rapid evaporation under exhaustion reduces the temperature to −145° C. (−229° F.). Running through this inner chamber is a tube containing oxygen gas under a pressure of 750 pounds to the square inch. The ‘critical point’ of oxygen gas, that is, the point above which no amount of pressure will reduce it to a liquid, is −115° C., but this pressure, at the temperature of −145° C., is amply sufficient to cause it to liquefy rapidly. In drawing off the liquid under this pressure, I lose nine-tenths of it by evaporation, and I have not yet seen how to diminish that loss. Every pint of it which I collect therefore represents ten pints manufactured. In all, I have thus far collected and used about fifty gallons, and the cost of machinery and experiments, very generously met by subscription among members of the Royal Institution and others, has been about five thousand pounds sterling.” It should be here stated that one of the most generous contributors to the fund has been Professor Dewar himself, a large fraction of the sum having come out of his own pocket.

Going more into detail, he makes clear some of the mechanical and chemical difficulties which beset him in the work. “The secret of my success,” he continues, “has been the mechanical arrangements combined with the use of ethylene. This is a volatile hydrocarbon, and is the chief illuminating constituent of coal gas. The only means of keeping it liquid for any length of time is to surround it with solid carbonic acid. Faraday was the first to call attention to the properties of ethylene, and we manufacture it by heating sulphuric acid in a glass retort protected by an iron cover to 160° C. Alcohol heated to 160° C. is allowed to drip into it and ethylene results, passing off as a gas, which is stored, after being purified. It is then compressed by two pumps, the first with a six-inch plunger and six-inch stroke, and the second a two-inch plunger and six-inch stroke. This liquefies it under the pressure stated. It is nasty stuff to handle, as, whenever it becomes mixed, by leakage or otherwise, with nitrous oxide or air, an explosion is imminent, and we have had not a few explosions in the course of the work. It liquefies at −103° C. (−152.4° F.), and when boiled in a partial vacuum absorbs a large amount of latent heat. The failure of preceding attempts to liquefy oxygen is due to lack of knowledge of its ‘critical point,’ and the law which that phrase describes. As long ago as 1851, Natterer subjected oxygen to a pressure of 2,800 atmospheres, or over thirty tons to the square inch. He obtained no result, because, as I have said, no amount of pressure will affect it above −115° C. I liquefy it at −145° C. for two reasons. The lower the temperature at which it is liquefied, the less is the pressure required upon the oxygen and the greater is the amount of latent heat which it absorbs in evaporating. By evaporating, under exhaustion, oxygen liquefied at −145° C., I get as low as −200° C., which I could not do were it liquefied at a higher temperature.

“Having obtained the liquid oxygen,” he continues, turning to the long table below the windows, “the question was how to store it for working purposes, with the least possible loss by evaporation. After various trials and experiments, we devised a set of vacuum vessels, each consisting of a tube or bottle for the liquid oxygen, sealed at the neck in a second tube or bottle, from which the air had been exhausted. I found the cheapest and best method of getting a vacuum to be the old Torricellian one of driving out the air with mercury vapor and then condensing the vapor. This had a further advantage. The tube containing the liquid oxygen was so cold that it froze the mercury vapor, and coated itself with a perfect metallic mirror, which by its reflection still further diminished the loss by radiated heat from the outside.” Without more ado, he lifted from a small frame one of the vacuum vessels referred to. It was a white glass jar, inside of which was what seemed to be a round metallic ball. Open at the neck, this ball was a bottle nearly filled with liquid oxygen, and by the light which reached it through the neck of the bottle it was a very clear pale blue liquid, which was evaporating quietly in a single thread of tiny bubbles, like a glass of champagne which has become nearly still.

It was one of those moments which Faraday would doubtless have regarded as solemn. To behold, for the first time, a liquid which your professors of chemistry have assured you was a gas and always would be a gas, is an experience which does not occur many times in a lifetime. After that, a sight of perpetual motion or the square of the circle would leave you calm. To know, furthermore, that this strange gas, which is the prime agent of all life, which is eight-ninths of all water and three-fourths of the entire earth, has been laid captive by science, reduced to a form which cannot fail to shed a flood of light on any number of abstruse problems in chemistry and mechanics, excites a deeper feeling. The pale blue liquid, which is strangely lustrous, seems truly magical. Moreover, it is a great surprise to see the liquid, which you expect to find under great pressure and ready to blow its containing vessel to pieces, evaporating quietly in the air, protected from heat by a vacuum on one side and its own cold vapor on the other. And so you can do nothing but stare at it in amazement, and gently shake the bottle, and turn from it to its discoverer with a feeling which is not entirely dissociated from awe. It has lost all its impressiveness to the professor, however, for he is busy preparing to illustrate some of its properties--an interesting introduction in themselves to the conditions which prevail twice as far below the freezing point of water as its boiling point lies above.

He begins by pouring some of the oxygen into a test tube, white fumes appearing as he does so from the freezing of the moisture in the surrounding air. Then he drops into the liquid oxygen in the test tube a bit of phosphorus. Despite the flaming energy with which these two combine at ordinary temperatures, there is no action. The phosphorus is as unaffected as a chip of wood in water. He takes it out and pours in some pure alcohol, whose freezing point is much below that of mercury. It freezes with a slight sputter into what you can only call alcohol ice. He takes out the ice and holds a match to it. There is no sign of combustion. Placed on a glass dish the alcohol ice melts into a thick, oily liquid, which also declines to burn. In a few seconds, however, it warms to its ordinary thinness and burns as hungrily as ever. Then comes an exhibition of the “spheroidal state.” A drop of water thrown towards a red-hot stove does not touch the stove, because the evaporation is so rapid that the forming gas lifts the water and keeps it moving about. Precisely the same thing occurs when the oxygen is dropped over a flat glass dish at the temperature of the air, which is red-hot to the oxygen, comparatively speaking. It dances about, shaking and boiling furiously. As he pours it, a tiny drop splashes on the professor’s hand, and he flings it off with a quick jerk. “It makes a sore worse than a burn,” he explains, “if it ever touches the skin.” Then he drops some of it into water. It floats quietly, and as it boils off into gas, freezes a cup of water around it, floating about comfortably in its own boat. Then came curious evidence of its magnetic properties. Pouring a little into a flat cup of rock salt, he placed the cup between the poles of an electro-magnet, the one which Faraday used. The boiling liquid, the moment that the circuit was completed, flew to the two terminals _en masse_ and clung there, still boiling away rapidly on the two points. A piece of cotton wool soaked in the liquid was held closely to one of the points, until all the oxygen had been sucked out of it, when it hung suspended between them. Liquid oxygen has a magnetic property, he said, which is about 1,000 as compared with 1,000,000, the magnetic property of iron. It is a non-conductor of electricity, and a spark one-tenth of a millimetre long from a coil machine, which would give a long spark in the air, would not pass through the liquid. It gave a flash now and then as a bubble of oxygen vapor came between the terminals. Liquid oxygen is, in fact, a high insulator.

Liquid oxygen at atmospheric pressure boils at −184° C. (−229.2° F.). By evaporating it under a diminished pressure, he gets much higher degrees of cold, and these have enabled him to both liquefy and solidify nitrogen and air. The experiment illustrating this was not only interesting; it was difficult to believe. In a double vacuum vessel the centre of which was an open test tube, and the second compartment a reservoir of liquid oxygen connected with an exhaust pump, he so lowered the pressure that the oxygen boiled tumultuously. As it did so, drops of clear liquid began to form on the sides of the test tube and gather at the bottom. It was liquid air, the oxygen and nitrogen of the atmosphere liquefying together at a temperature of −197.2° (−322.9° F.). He poured some of the liquid air into a second tube, and then showed how the nitrogen, which liquefies at a temperature fourteen degrees below oxygen, boiled off first. A smouldering splinter of wood held at the mouth of the tube was extinguished. A few moments later when it was again held there, it burst into brilliant flame. The nitrogen had all evaporated, and the oxygen was coming off. He explained that air became solid under pressure at −207° C. (−340.6° F.). It was a structureless glass, and he had not determined whether or not the oxygen in it was solid or was held suspended as a jelly. Nitrogen solidified under pressure at −210° C. (−346° F.). It was a white crystalline substance. He had no knowledge as yet whether oxygen crystallized in solidifying, but his belief was that it would not.

Concerning hydrogen, most elusive of all the gases, he had no present expectation of attaining liquefaction. Its critical point was below −210° C., and its boiling point −250° C. He had no means as yet of attacking the problem. In fact, the only thermometer he was able to use at these low temperatures was one which used hydrogen expansion as a measure of temperature. His main reliance in measuring low temperatures was a thermo-electric junction. Deeply interesting also was his description of liquid ozone, that strange form of oxygen which though identical with it in constitution is different in molecular arrangement. He obtains twenty per cent. of ozone from liquid oxygen by electrical stimulation, the ozone being of a very dark blue color, as dark as concentrated indigo. It is highly unstable, a beam of light having caused it to explode on one occasion, and its study even in small quantities requires all the delicacy of manipulation which is one of the special directions in which Professor Dewar as a chemist occupies the foremost rank.

Through all these explanations, and others too elaborate and too technical for these pages, he had spoken in the clear, emphatic way which is characteristic of men who deal with abstruse subjects, and desire, from long habit, to present them with the maximum of clearness and the minimum of words. His speech is incisive, the utterances of an energetic and concentrated mind. Over a cup of tea upstairs, however, he spoke more slowly and dwelt with interest upon some of the many strange results which have already met his eyes in the region of −200° Centigrade.

“As we approach the zero point of absolute temperature,” said he, “we seem to be nearing what I can only call the death of matter. Pure metals undergo molecular changes which cannot yet be defined, but which entirely alter their characteristics as we know them. Tensile strength, electrical resistance, in fact, the whole character of the metal as we are acquainted with it, appears to change. At −200°, for instance, iron becomes as good an electrical conductor as copper, while it is more than probable that at the zero of absolute temperature, if not before, the electrical resistance of all metals reaches its zero point. The alloys do not follow the same rule, being much less affected. Carbon is a strange exception, its electrical resistance increasing with cold and decreasing with heat. The effect upon colors is also remarkable, and opens up a wide field for experiment and investigation. In fact, the most marked and immediate effect of my experiments will appear, I think, in the field of magneto-optics. You have seen a red oxide of mercury turn yellow when cooled to the temperature of liquid oxygen, and regain its original color upon returning to the temperature of the air. In the same way, sulphur becomes white. Bichromate of potash becomes also white. A solution of iodine in alcohol becomes colorless, as does ferric chloride, a deep red at the temperature of the air. They all regain their colors upon returning to the ordinary temperature. At these low temperatures chemical action ceases, as you have seen. I supposed the rule was invariable, but found that a photographic plate placed in liquid oxygen was still acted upon by energy from the outside, and at even −200° C. was sensitive to light.

“The effect upon bacterial life is also not what one would expect. Though it is destroyed by boiling in water, a temperature of 100° C., it can still endure unaffected a degree of cold much greater in proportion. I have submitted putrefying blood, milk, seeds, etc., for the space of an hour, to a temperature of −182° C., but found that they afterwards went on putrefying or germinating as the case happened to be. This is interesting in one way, as it gives color to Lord Kelvin’s suggestion that the first life might have been brought to this planet by a seed-bearing meteorite, though it does not explain,” he added with a smile, “how the meteorite was originally equipped with seeds. It shows, however, that spores may live upon a planet through long periods of low temperature. In the phenomena of diminishing electrical resistance and its final disappearance, I look for much new light upon the mystery of electricity itself. The changes in the characteristics of metals already observed enlock lessons whose scope we have not yet begun to measure. In fact,” said he, “for a long time to come I shall confine myself to the many fields of research which the temperatures already attained have opened up.”

Concerning the zero of absolute temperature, Professor Dewar was disinclined to theorize. As to its being the temperature of inter-stellar space, he has not yet come to any final conclusion, though he expressed the view that the strange white and shining night clouds which have puzzled the astronomers were composed of carbonic acid gas frozen solid. Nor does he yet, despite the temperatures reached, see how the zero is to be attained. He, like the Arctic explorers of the past, has reached a point beyond which no appliances of modern science can carry him. The mysteries which cluster about this point are so many, however, that the efforts to reach it will be untiring from this time forth. That its discovery will be a key to many unsolved problems in electricity, in matter, in light, and the great inscrutable mystery of life itself, is not to be doubted. This is an age of constant change in scientific conceptions and traditions, every marked advance in any one science tending to cause more or less of a readjustment of existing views in every other. Science has long been editing the Book of Genesis with an unsparing pen, and with the attainment of the zero of absolute temperature the command “Let there be light” may take on a meaning which the profoundest philosopher or scientist of the present time cannot remotely conceive.

THE HOUSE WITH THE TALL PORCH.

BY GILBERT PARKER.

No one ever visited at it except the little chemist, the avocat and Medallion; and Medallion, though merely an auctioneer, was the only one on terms of intimacy with its owner, an old seigneur who for many years had never stirred beyond the limits of his little garden. At rare intervals he might be seen sitting in the large stone porch which gave overweighted dignity to the house, itself not very large. An air of mystery surrounded the place: in summer the grass was rank, the trees seemed huddled together in gloom about the house, the vines appeared to ooze on the walls, and at one end, where the window-shutters were always closed and barred, a great willow drooped and shivered; in winter the stone walls showed naked and grim among the gaunt trees and furtive shrubs.

None who ever saw the seigneur could forget him--a tall figure with stooping shoulders; a pale, deeply-lined, clean-shaven face; and a forehead painfully white, with blue veins showing; the eyes handsome, penetrative, brooding, and made indescribably sorrowful by the dark skin around them. There were those in Pontiac, such as the curé, who remembered when the seigneur was constantly to be seen in the village; and then another person was with him always, a young, tall youth, his son. They were fond and proud of each other, and were religious and good citizens in a high-bred, punctilious way. Then the seigneur was all health and stalwart strength. But one day a rumor went abroad that the seigneur had quarrelled with his son because of the wife of Farette the miller. No one outside knew if the thing was true, but Julie, the miller’s wife, seemed rather to plume herself that she had made a stir in her little world. Yet the curious habitants came to know that the young man had gone, and after a good many years his having once lived there was almost a tradition. But the little chemist remembered whenever he set foot inside the tall porch; the avocat was kept in mind by papers which he was called upon to read and alter from time to time; the curé never forgot, because when the young man went he lost not one of his flock, but two; and Medallion, knowing something of the story, had it before him with gradually increasing frequency; besides, he had wormed a deal of truth out of the miller’s wife. He knew that the closed, barred rooms were the young man’s; and he knew, also, that the old man was waiting, waiting, in a hope which he never even named to himself.

One day the silent old housekeeper came rapping at Medallion’s door, and simply said to him, “Come--the seigneur!” Medallion went, and for hours sat beside the seigneur’s chair, while the little chemist watched and sighed softly in a corner, now and again rising to feel the sick man’s pulse and to prepare a draught. The housekeeper hovered behind the high-backed chair, and when the seigneur dropped his handkerchief--now, as always, of the exquisite fashion of a past century--put it gently in his hand, and he would incline his head ever so gently, and wipe his pale, dry lips with it.

Once when the little chemist touched his wrist, his dark eyes rested on him with inquiry, and he said: “How long?”

It was useless trying to shirk the persistency of that look. “Ten hours, perhaps, sir,” he said with painful shyness.

The seigneur seemed to draw himself up a little, and his hand grasped his handkerchief tightly for an instant; then he said: “So long? Thank you.” Then, after a little, his eyes turned to Medallion, and he seemed about to speak, but still kept silent. His chin dropped on his breast, and for a time he was motionless and shrunken; but still there was a strange little curl of pride--or disdain--to his lips. At last he drew up his head, his shoulders heavily came erect to the carved back of the chair, where, strange to say, the stations of the cross were figured, and he said with a cold, ironical voice: “The angel of patience has lied.”

The evening wore on, and there was no sound save the ticking of the clock, the beat of rain upon the windows, and the deep breathing of the seigneur. Presently he started, his eyes opened wide, and his whole body seemed to listen. “I heard a voice,” he said.

“No one spoke, my master,” said the housekeeper.

“It was a voice without,” he said.

“Monsieur,” said the little chemist, “it was the wind in the eaves.”

His face was almost painfully eager and sensitively alert. “Hush,” he said, “I hear a voice in the tall porch.”

“Sir,” said Medallion, laying a hand respectfully on his arm, “it is nothing.”

With a light on his face and a proud, trembling energy, he got to his feet. “It is the voice of my son,” he said. “Go, go, and bring him in.”

No one moved. But he was not to be disobeyed. His ears had been growing keener as he neared the subtle atmosphere of that brink where a man strips himself to the soul for a lonely voyaging, and he waved the woman to the door. “Wait,” he said, as her hand fluttered at the handle, “take him to another room. Prepare a supper such as we used to have. When it is ready I will come. But listen, and obey me. Do not tell him that I have but half a dozen hours of life. Go, and bring him in.”

It was as he said. She found the son, weak and fainting, fallen within the porch, a worn, bearded man, returned from failure and suffering and the husks of evil. They clothed him and cared for him, and strengthened him with wine, while the woman wept over him, and at last set him at the loaded, well-lighted table. Then the seigneur came in, leaning his arm very lightly on that of Medallion, with a kingly air, and, greeting his son before them all as if they had parted yesterday, sat down. For two hours they sat there, and the seigneur talked gayly, with a color, and his fine eyes glowing; at last he rose, lifted his glass, and said: “The angel of patience is wise: I drink to my son.” He was about to say something more, but a sudden whiteness passed over his face. He drank off the wine and, as he put the glass down, shivered, and fell back in his chair. “Three hours short, chemist,” he said, and smiled, and was still--forever.

STRANGER THAN FICTION.

THE BRONTËS AL FRESCO. THE BRONTËS AND THE GHOSTS. THE DEVIL AND THE POTATO BLIGHT. THE GREAT BRONTË FIGHT.

BY DOCTOR WILLIAM WRIGHT.