Part 20

The varieties of the banana are infinite in number, and, as in most other plants of ancient cultivation, they shade off into one another by infinitesimal gradations. Two principal sorts, however, are commonly recognised—the true banana of commerce, and the common plantain. The banana proper is eaten raw, as a fruit, and is allowed accordingly to ripen thoroughly before being picked for market; the plantain, which is the true food-stuff of all the equatorial region in both hemispheres, is gathered green and roasted as a vegetable, or, to use the more expressive West Indian negro phrase, as a bread-kind. Millions of human beings in Asia, Africa, America, and the islands of the Pacific Ocean live almost entirely on the mild and succulent but tasteless plantain. Some people like the fruit; to me personally it is more suggestive of a very flavorless over-ripe pear than of anything else in heaven or earth or the waters that are under the earth—the latter being the most probable place to look for it, as its taste and substance are decidedly watery. Baked dry in the green state “it resembles roasted chestnuts,” or rather baked parsnip; pulped and boiled with water it makes “a very agreeable sweet soup,” almost as nice as peasoup with brown sugar in it; and cut into slices, sweetened, and fried, it forms “an excellent substitute for fruit pudding,” having a flavor much like that of potatoes _à la maître d’hôtel_ served up in treacle.

Altogether a fruit to be sedulously avoided, the plantain, though millions of our spiritually destitute African brethren haven’t yet for a moment discovered that it isn’t every bit as good as wheaten bread and fresh butter. Missionary enterprise will no doubt before long enlighten them on this subject, and create a good market in time for American flour and Manchester piece-goods.

Though by origin a Malayan plant, there can be little doubt that the banana had already reached the mainland of America and the West India Islands long before the voyage of Columbus. When Pizarro disembarked upon the coast of Peru on his desolating expedition, the mild-eyed, melancholy, doomed Peruvians flocked down to the shore and offered him bananas in a lordly dish. Beds composed of banana leaves have been discovered in the tombs of the Incas, of date anterior, of course, to the Spanish conquest. How did they get there? Well, it is clearly an absurd mistake to suppose that Columbus discovered America; as Artemus Ward pertinently remarked, the noble Red Indian had obviously discovered it long before him. There had been intercourse of old, too, between Asia and the Western Continent; the elephant-headed god of Mexico, the debased traces of Buddhism in the Aztec religion, the singular coincidences between India and Peru, all seem to show that a stream of communication, however faint, once existed between the Asiatic and American worlds. Garcilaso himself, the half-Indian historian of Peru, says that the banana was well known in his native country before the conquest, and that the Indians say “its origin is Ethiopia.” In some strange way or other, then, long before Columbus set foot upon the low sandbank of Cat’s Island, the banana had been transported from Africa or India to the Western hemisphere.

If it were a plant propagated by seed, one would suppose that it was carried across by wind or waves, wafted on the feet of birds, or accidentally introduced in the crannies of drift timber. So the coco-nut made the tour of the world ages before either of the famous Cooks—the Captain or the excursion agent—had rendered the same feat easy and practicable; and so, too, a number of American plants have fixed their home in the tarns of the Hebrides or among the lonely bogs of Western Galway. But the banana must have been carried by man, because it is unknown in the wild state in the Western Continent; and, as it is practically seedless, it can only have been transported entire, in the form of a root or sucker. An exactly similar proof of ancient intercourse between the two worlds is afforded us by the sweet potato, a plant of undoubted American origin, which was nevertheless naturalised in China as early as the first centuries of the Christian era. Now that we all know how the Scandinavians of the eleventh century went to Massachusetts, which they called Vine-land, and how the Mexican empire had some knowledge of Acadian astronomy, people are beginning to discover that Columbus himself was after all an egregious humbug.

In the old world the cultivation of the banana and the plantain goes back, no doubt, to a most immemorial antiquity. Our Aryan ancestor himself, Professor Max Müller’s especial _protégé_, had already invented several names for it, which duly survive in very classical Sanskrit. The Greeks of Alexander’s expedition saw it in India, where “sages reposed beneath its shade and ate of its fruit, whence the botanical name, _Musa sapientum_.” As the sages in question were lazy Brahmans, always celebrated for their immense capacity for doing nothing, the report, as quoted by Pliny, is no doubt an accurate one. But the accepted derivation of the word _Musa_ from an Arabic original seems to me highly uncertain; for Linnæus, who first bestowed it on the genus, called several other allied genera by such cognate names as Urania and Heliconia. If, therefore, the father of botany knew that his own word was originally Arabic, we cannot acquit him of the high crime and misdemeanor of deliberate punning. Should the Royal Society get wind of this, something serious would doubtless happen; for it is well known that the possession of a sense of humor is absolutely fatal to the pretensions of a man of science.

Besides its main use as an article of food, the banana serves incidentally to supply a valuable fibre, obtained from the stem, and employed for weaving into textile fabrics and making paper. Several kinds of the plantain tribe are cultivated for this purpose exclusively, the best known among them being the so-called manilla hemp, a plant largely grown in the Philippine Islands. Many of the finest Indian shawls are woven from banana stems, and much of the rope that we use in our houses comes from the same singular origin. I know nothing more strikingly illustrative of the extreme complexity of our modern civilisation than the way in which we thus every day employ articles of exotic manufacture in our ordinary life without ever for a moment suspecting or inquiring into their true nature. What lady knows when she puts on her delicate wrapper, from Liberty’s or from Swan and Edgar’s, that the material from which it is woven is a Malayan plantain stalk? Who ever thinks that the glycerine for our chapped hands comes from Travancore coco-nuts, and that the pure butter supplied us from the farm in the country is colored yellow with Jamaican annatto? We break a tooth, as Mr. Herbert Spencer has pointed out, because the grape-curers of Zante are not careful enough about excluding small stones from their stock of currants; and we suffer from indigestion because the Cape wine-grower has doctored his light Burgundies with Brazilian logwood and white rum, to make them taste like Portuguese port. Take merely this very question of dessert, and how intensely complicated it really is. The West Indian bananas keep company with sweet St. Michaels from the Azores, and with Spanish cobnuts from Barcelona. Dried fruits from Metz, figs from Smyrna, and dates from Tunis lie side by side on our table with Brazil nuts and guava jelly and damson cheese and almonds and raisins. We forget where everything comes from nowadays, in our general consciousness that they all come from the Queen Victoria Street Stores, and any real knowledge of common objects is rendered every day more and more impossible by the bewildering complexity and variety, every day increasing, of the common objects themselves, their substitutes, adulterates, and spurious imitations. Why, you probably never heard of manilla hemp before, until this very minute, and yet you have been familiarly using it all your lifetime, while 400,000 hundredweights of that useful article are annually imported into this country alone. It is an interesting study to take any day a list of market quotations, and ask oneself about every material quoted, what it is and what they do with it.

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.