Eclectic Magazine of Foreign Literature, Science, and Art, April 1885

For example, can you honestly pretend that you really understand the use and importance of that valuable object of everyday demand, fustic? I remember an ill-used telegraph clerk in a tropical colony once complaining to me that English cable operators were so disgracefully ignorant about this important staple as invariably to substitute for its name the word “justice” in all telegrams which originally referred to it. Have you any clear and definite notions as to the prime origin and final destination of a thing called jute, in whose sole manufacture the whole great and flourishing town of Dundee lives and moves and has its being? What is turmeric? Whence do we obtain vanilla? How many commercial products are yielded by the orchids? How many totally distinct plants in different countries afford the totally distinct starches lumped together in grocers’ lists under the absurd name of arrowroot? When you ask for sago do you really see that you get it? and how many entirely different objects described as sago are known to commerce? Define the use of partridge canes and cohune oil. What objects are generally manufactured from tucum? Would it surprise you to learn that English door-handles are commonly made out of coquilla nuts? that your wife’s buttons are turned from the indurated fruit of the Tagua palm? and that the knobs of umbrellas grew originally in the remote depths of Guatemalan forests? Are you aware that a plant called manioc supplies the starchy food of about one-half the population of tropical America? These are the sort of inquiries with which a new edition of “Mangnall’s Questions” would have to be filled; and as to answering them – why, even the pupil-teachers in a London Board School (who represent, I suppose, the highest attainable level of human knowledge) would often find themselves completely nonplussed. The fact is, tropical trade has opened out so rapidly and so wonderfully that nobody knows much about the chief articles of tropical growth; we go on using them in an uninquiring spirit of childlike faith, much as the Jamaica negroes go on using articles of European manufacture about whose origin they are so ridiculously ignorant that one young woman once asked me whether it was really true that cotton handkerchiefs were dug up out of the ground over in England. Some dim confusion between coal or iron and Manchester piece-goods seemed to have taken firm possession of her infantile imagination.

That is why I have thought that a treatise De Banana might not, perhaps, be wholly without its usefulness to the English magazine-reading world. After all, a food-stuff which supports hundreds of millions among our beloved tropical fellow-creatures ought to be very dear to the heart of a nation which governs (and annually kills) more black people, taken in the mass, than all the other European powers put together. We have introduced the blessings of British rule – the good and well-paid missionary, the Remington rifle, the red-cotton pocket-handkerchief, and the use of “the liquor called rum” – into so many remote corners of the tropical world that it is high time we should begin in return to learn somewhat about fetishes and fustic, Jamaica and jaggery, bananas and Buddhism. We know too little still about our colonies and dependencies. “Cape Breton an island!” cried King George’s Minister, the Duke of Newcastle, in the well-known story, “Cape Breton an island! Why, so it is! God bless my soul! I must go and tell the King that Cape Breton’s an island.” That was a hundred years ago; but only the other day the Board of Trade placarded all our towns and villages with a flaming notice to the effect that the Colorado beetle had made its appearance at “a town in Canada called Ontario,” and might soon be expected to arrive at Liverpool by Cunard steamer. The right honorables and other high mightinesses who put forth the notice in question were evidently unaware that Ontario is a province as big as England, including in its borders Toronto, Ottawa, Kingston, London, Hamilton, and other large and flourishing towns. Apparently, in spite of competitive examinations, the schoolmaster is still abroad in the Government offices. —Cornhill Magazine.

TURNING AIR INTO WATER

It has not yet been done; but the following telegrams, received on the 9th and 16th of April, 1883, from Cracow, by the Paris Academy of Sciences, show that chemists have come very near doing it. “Oxygen completely liquefied; the liquid colorless like carbonic acid.” “Nitrogen liquefied by explosion; liquid colorless.” Thus the two elements that make up atmospheric air have actually been liquefied, the successful operator being a Pole, Wroblewski, who had worked in the laboratory of the French chemist, Cailletet, learnt his processes, copied his apparatus, and then, while Cailletet, who owns a great iron-foundry down in Burgundy, was looking after his furnaces, went off to Poland, and quietly finished what his master had for years been trying after. Hence heart-burnings, of which more anon, when we have followed the chase up to the point where Cailletet took it up. I use this hunting metaphor, for the liquefaction of gases has been for modern chemists a continual chase, as exciting as the search for the philosopher’s stone was to the old alchemists.

Less than two hundred and fifty years ago, no one knew anything about gas of any kind. Pascal was among the first who guessed that air was “matter” like other things, and therefore pressed on the earth’s surface with a weight proportioned to its height. Torricelli had made a similar guess two years before, in 1645. But Pascal proved that these guesses were true by carrying a barometer to the top of the Puy de Dôme near Clermont. Three years after, Otto von Guerecke invented the air-pump, and showed at Magdeburg his grand experiment – eight horses pulling each way, unable to detach the two hemispheres of a big globe out of which the air had been pumped. Then Mariotte in France, and Boyle in England, formulated the “Law,” which the French call Mariotte’s, the English Boyle’s, that gases are compressible, and that their bulk diminishes in proportion to the pressure. But electricity with its wonders threw pneumatics into the background; and, till Faraday, nothing was done in the way of verifying Boyle’s Law except by Van Marum, a Haarlem chemist, who, happening to try whether the Law applied to gaseous ammonia, was astonished to find that under a pressure of six atmospheres that gas was suddenly changed into a colorless liquid. On Van Marum’s experiment Lavoisier based his famous generalisation that all bodies will take any of the three forms, solid, fluid, gaseous, according to the temperature to which they are subjected – i.e., that the densest rock is only a solidified vapor, and the lightest gas only a vaporised solid. Nothing came of it, however, till that wonderful bookbinder’s apprentice, Faraday, happened to read Mrs. Marcet’s Conversations while he was stitching it for binding, and thereby had his mind opened; and, managing to hear some of Sir H. Davy’s lectures, wrote such a good digest of them, accompanied by such a touching letter – ”Do free me from a trade that I hate, and let me be your bottle-washer” – that the good-hearted Cornishman took the poor blacksmith’s son, then twenty-one years old, after eight years of book-stitching, and made him his assistant, “keeping him in his place,” nevertheless, which, for an assistant in those days, meant feeding with the servants, except by special invitation.

This was in 1823, and next year Faraday had liquefied chlorine, and soon did the same for a dozen more gases, among them protoxide of nitrogen, to liquefy which, at a temperature of fifty degrees Fahrenheit, was needed a pressure of sixty atmospheres – sixty times the pressure of the air – i.e., nine hundred pounds on every square inch. Why, the strongest boilers, with all their thickness of iron, their rivets, their careful hammering of every plate to guard against weak places, are only calculated to stand about ten atmospheres; no wonder then that Faraday, with nothing but thick glass tubes, had thirteen explosions, and that a fellow-experimenter was killed while repeating one of his experiments. However, he gave out his “Law,” that any gas may be liquefied if you put pressure enough on it. That “if” would have left matters much where they were had not Bussy, in 1824, argued: “Liquid is the middle state between gaseous and solid. Cold turns liquids into solids; therefore, probably cold will turn gases into liquids.” He proved this for sulphurous acid, by simply plunging a bottle of it in salt and ice; and it is by combining the two, cold and pressure, that all subsequent results have been attained. How to produce cold, then, became the problem; and one way is by making steam. You cannot get steam without borrowing heat from something. Water boils at two hundred and twelve degrees Fahrenheit, and then you may go on heating and heating till one thousand degrees more heat have been absorbed before steam is formed. The thermometer, meanwhile, never rises above two hundred and twelve degrees, all this extra heat becoming what is called latent, and is probably employed in keeping asunder the particles which when closer together form water. The greater the expansive force, the more heat becomes latent or used up in this way. This explains the paradox that, while the steam from a kettle-spout scalds you, you may put your hand with impunity into the jet discharged from a high-pressure engine. The high-pressure steam, expanding rapidly when it gets out of confinement, uses up all its heat (makes it all “latent”) in keeping its particles distinct. It is the same with all other vapors: in expanding they absorb heat, and, therefore, produce cold; and, therefore, as many substances turn into steam at far lower temperatures than water does, this principle of “latent heat,” invented by Black, and, after long rejection, accepted by chemists, has been very helpful in the liquefying of gases by producing cold.

The simplest ice-machine is a hermetically-sealed bottle connected with an air-pump. Exhaust the air, and the water begins to boil and to grow cold. As the air is drawn off, the water begins to freeze; and if – by an ingenious device – the steam that it generates is absorbed into a reservoir of sulphuric acid, or any other substance which has a great affinity for watery vapor, a good quantity of ice is obtained. This is the practical use of liquefying gases; naturally, they all boil at temperatures much below that of the air, in which they exist in the vaporised state that follows after boiling. Take, therefore, your liquefied gas; let it boil and give off its steam. This steam, absorbing by its expansion all the surrounding heat, may be used to make ice, to cool beer-cellars, to keep meat fresh all the way from New Zealand, or – as has been largely done at Suez – to cool the air in tropical countries. Put pressure enough on your gas to turn it into a liquid state, at the same time carrying away by a stream of water the heat that it gives off in liquefying. Let this liquid gas into a “refrigerator,” where it boils and steams, and draws out the heat; and then by a sucking-pump drive it again into the compressor, and let the same process go on ad infinitum, no fresh material being needed, nothing, in fact, but the working of the pump. Sulphurous acid is a favorite gas, ammonia is another; and – besides the above practical uses – they have been employed in a number of startling experiments.

Perhaps the strangest of these is getting a bar of ice out of a red-hot platinum crucible. The object of using platinum is simply to resist the intense heat of the furnace in which the crucible is placed. Pour in sulphurous acid and then fill up with water. The cold raised by vaporising the acid is so intense that the water will freeze into a solid mass. Indeed, the temperature sometimes goes down to more than eighty degrees below freezing. A still more striking experiment is that resulting from the liquefying of nitrous oxide – protoxide of nitrogen, or laughing-gas. This gas needs, as was said, great pressure to liquefy it at an ordinary temperature. At freezing point only a pressure of thirty atmospheres is needed to liquefy it. It then boils if exposed to the air, radiating cold – or, rather, absorbing heat – till it falls to a temperature low enough to freeze mercury. But it still, wonderful to say, retains the property which, alone of all the gases, it shares with oxygen – of increasing combustion. A match that is almost extinguished burns up again quite brightly when thrust into a bag of ordinary laughing-gas; while a bit of charcoal, with scarcely a spark left in it, glows to the intensest white heat when brought in contact with this same gas in its liquid form, so that you have the charcoal at, say, two thousand degrees Fahrenheit, and the gas at some one hundred and fifty degrees below zero. Carbonic acid gas is just the opposite of nitrous oxide, in that it quenches fire and destroys life; but, when liquefied, it develops a like intense cold. Liquefy it and collect it under pressure, in strong cast-iron vessels, and then suddenly open a tap and allow the vapor to escape. In expanding, it grows so cold – or, strictly speaking, absorbs, makes latent, so much heat – that it produces a temperature low enough to turn it into fog and then into frozen fog, or snow. This snow can be gathered in iron vessels, and mixed with either it forms the strongest freezing mixture known, turning mercury into something like lead, so that you can beat the frozen metal with wooden mallets and can mould it into medals and such-like.

Amid these and such-like curious experiments, we must not forget the “Law” that the state of a substance depends on its temperature – solid when it is frozen hard enough, liquid under sufficient pressure, gaseous when free from pressure and at a sufficiently high temperature. But though first Faraday, and then the various inventors of refrigerating-machines – Carré, Tellier, Natterer, Thilorier – succeeded in liquefying so many gases, hydrogen and the two elements of the atmosphere resisted all efforts. By plunging oxygen in the sea, to the depth of a league, it was subjected to a pressure of four hundred atmospheres, but there was no sign of liquefaction. Again, Berthelot fastened a tube, strong and very narrow, and full of air, to a bulb filled with mercury. The mercury was heated until its expansion subjected the air to a pressure of seven hundred and eighty atmospheres – all that the glass could stand – but the air remained unchanged. Cailletet managed to get one thousand pressures by pumping mercury down a long, flexible steel tube upon a very strong vessel, full of air; but nothing came of it, except the bursting of the vessel, nor was there any more satisfactory result in the case of hydrogen.

One result, at any rate, was established – that there is no law of compression like that named after Boyle or Mariotte, but that every gas behaves in a way of its own, without reference to any of the others, each having its own “critical point” of temperature, at which, under a certain pressure, it is neither liquid nor gaseous, but on the border-land between the two, and will remain in this condition so long as the temperature remains the same. Hence, air being just in this state of gaseo-liquid, the first step towards liquefying it must be to lower its temperature, and so get rid of its vapor by increasing its density. The plan adopted, both by Cailletet in Paris, and by Raoul Pictet (heir of a great scientific name) in Geneva, was to lower the temperature by letting off high-pressure steam. This had been so successful in the case of carbonic acid gas as to turn the vapor into snow; and in 1877 Cailletet pumped oxygen into a glass tube, until the pressure was equal to three hundred atmospheres. He then cooled it to four degrees Fahrenheit below zero, and, opening a valve, let out a jet of gaseous vapor, which, while expanding, caused intense cold, lowering the temperature some three hundred degrees, and turning the jet of vapor into fog. Here, then, was a partial liquefaction, and the same was effected in the case of nitrogen. Pictet did much the same thing. Having set up at Geneva a great ice-works (his refrigerating agency being sulphurous acid in a boiling state), he had all the necessary apparatus, and was able to subject oxygen to a pressure of three hundred and twenty atmospheres, and by means of carbonic acid boiling in vacuo, to cool the vessel containing it down to more than two hundred degrees Fahrenheit below zero. He could not watch the condition in which the gas was; but it was probably liquefied, for, when a valve was suddenly opened, it began to bubble furiously, and rushed out in the form of steam. Pictet thought he had also succeeded in liquefying hydrogen, the foggy vapor of the jet being of a steely grey color; for hydrogen has long been suspected to be a metal, of which water is an oxide, and hydrochloric acid a chloride. Nay, some solid fragments came out with the jet of vapor, and fell like small shot on the floor, and at first the sanguine experimenter thought he had actually solidified the lightest of all known substances. This, however, was a mistake; it was some portion of his apparatus which had got melted. Neither had the liquefaction of oxygen or nitrogen been actually witnessed, though the result had been seen in the jet of foggy vapor.

Cailletet was on the point of trying his experiment over again in vacuo, so as to get a lower temperature, when the telegrams from Wroblewski showed that the Pole had got the start of him. Along with a colleague, Obszewski, Cailletet’s disloyal pupil set ethylene boiling in vacuo, and so brought the temperature down to two hundred and seventy degrees Fahrenheit below zero. This was the lowest point yet reached, and it was enough to turn oxygen into a liquid a little less dense than water, having its “critical point” at about one hundred and sixty-eight degrees Fahrenheit below zero. A few days after, nitrogen was liquefied by the same pair of experimenters, under greater atmospheric pressure at a somewhat higher temperature.

The next thing is to naturally ask: What is the use of all this? That remains to be proved. The most unlikely chemical truths have often brought about immense practical results. All that we can as yet say is, that there is now no exception to the law that matter of all kinds is capable of taking the three forms, solid, aqueous, gaseous.

The French savans are not content with saying this. They are very indignant at Wroblewski stealing Cailletet’s crown just as it was going to be placed on the Frenchman’s head. It was sharp practice, for all that a scientific discoverer has to look to is the fame which he wins among men. The Academy took no notice of the interloping Poles, but awarded to Cailletet the Lacaze Prize, their secretary, M. Dumas, then lying sick at Cannes, expressing their opinion in the last letter he ever wrote. “It is Cailletet’s apparatus,” says M. Dumas, “which enabled the others to do what he was on the point of accomplishing. He, therefore, deserves the credit of invention; the others are merely clever and successful manipulators. What has been done is a great fact in the history of science, and it will link the name of Cailletet with those of Lavoisier and Faraday,” So far M. Dumas, who might, one fancies, have said something for Pictet, only a fortnight behind Cailletet in the experiment which practically liquefied oxygen. His case is quite different from Wroblewski’s, for he and Cailletet had been working quite independently, just as Leverrier and Adams had been when both discovered the new planet Neptune. Such coincidences so often happen when the minds of men are turned to the same subject. Well, the scientific world is satisfied now that the elements of air can be liquefied; but I want to see the air itself liquefied, as what it is – a mechanical, not a chemical compound. For from such liquefaction, one foresees a great many useful results. You might carry your air about with you to the bottom of mines or up in balloons; you might even, perhaps, store up enough by-and-by to last for a voyage to the moon. —All the Year Round.

THE HEALTH AND LONGEVITY OF THE JEWS

BY P. KIRKPATRICK PICARD, M.D., M.R.C.S

In these days, when sanitation claims a large share of attention, and when questions relating to the public health are canvassed and discussed on all sides, it may be of service to ask what lessons are to be learned from the diet, habits, and customs of the Jews. It is not generally known that their health and longevity are superior to those of other races, a fact which has been noted by careful observers from early times in this and other countries. An experiment, extending over thousands of years, has been made as to the sanitary value of certain laws in the Mosaic code. The test has been applied in the most rigid way, and if it had failed at any period in their eventful history, their name alone, like that of the Assyrian and Babylonian, would have remained to testify to their existence as a nation. The three deadly enemies of mankind – war, famine, and pestilence – have at times been let loose upon them. They have stood firm as a rock against the crushing power of oppression, when exercised at the call of political or religious antipathy. They have been pursued with relentless persecution, from city to city, and from one country to another, in the name of our holy religion. Restricted as to their trade, singled out to bear the burden of special taxation, confined in the most miserable and unhealthy quarters of the towns where they were permitted to dwell, living in the constant fear of robbery without redress, of violence without succor, of poverty without relief, of assaults against their persons, honor, and religion without hope of protection; in spite of woe after woe coming upon them, like the waves of a pitiless sea, they have not been broken to pieces and swallowed up, leaving not a wreck behind. No other race has had the fiery trials that they have gone through, yet, like the three Hebrew youths in the furnace, the smell of fire is not found on them. To-day their bodily vigor is unequalled, and their moral and mental qualities are unsurpassed.

How has it happened that, after being compassed about for centuries with so many troubles, they have at the present time all the requisites that go to form a great nation, and are, in numbers, energy, and resources, on a level with their forefathers in the grandest period of their history? It is not enough to say that all this has come to pass according to the will of God, and that their continued existence is owing to His intervention on their behalf. No doubt it is a miracle in the sense that it is contrary to all human experience, for no other nation has lived through such perilous times of hardship and privation. But as it was in the wilderness so it has been in all their wanderings down the stream of time; the miracle was supplemented by the use of means, without which God’s purpose regarding them would have failed. The blessing of long life and health, promised to them by the mouth of Moses, has not been withheld. Several texts might be quoted, but one will suffice. In Deuteronomy iv. 40, we read, “Thou shall keep therefore his statutes, and his commandments, that it may go well with thee, and with thy children after thee, and that thou mayest prolong thy days upon the earth, which the Lord thy God giveth thee, for ever.” With a promise so rich with blessing, conditional on their obedience, they have through all the ages been monuments of God’s faithfulness, and are to this day in the enjoyment of its advantages.

The following statistics, for which I am indebted to the kindness of Dr. A. Cohen, who has collected them from different sources, will serve to prove their superiority in respect of health and longevity. In the town of Fürth, according to Mayer, the average duration of life amongst the Christians was 26 years, and amongst the Jews 37 years. During the first five years of childhood the Christian death-rate was 14 per cent. and the Jewish was 10 per cent. The same proportion of deaths, it is said, exists in London. Neufville has found that in Frankfort the Jews live eleven years longer than the Christians, and that of those who reach the age of 70 years 13 are Christians and 27 are Jews. In Prussia, from 1822 to 1840, it has been ascertained that the Jewish population increased by 3-1/2 per cent. more than the Christian, there being 1 birth in 28 of the Jews to 1 in 25 of the Christians, and 1 death in 40 of the Jews to 1 in 34 of the Christians.