LIGHT UNDER WATER.—PEARL-FISHING AND TURTLE-HUNTING.
Frank was curious to know how it was possible to see under water. He thought it would be dark at great depths, and, if so, it would be impossible to do anything there on account of the darkness. Lamps could not be made to burn under water, and until this was done the explorers of the sea could not make much progress.
Captain Johnson replied that Frank's theory was correct. As the diver goes down the light becomes more and more dim, but the dimness or the absence of it depends upon the clearness of the water where he is at work. If the water is clear and the sunlight good, there is no trouble about seeing at any depth to which a diver may safely descend. In a stream like the Mississippi or the Missouri river it will be darker at ten feet deep than in the Mediterranean at a hundred.
"But science has come to our aid," he continued, "by giving us the electric light. There is one form of it that can burn in a vacuum—in fact, it needs a vacuum for its proper working. Now all you have to do is to insulate the wires leading to the glass globe that holds the light, and you can carry it under the water without the least trouble.
"For ordinary purposes there is a very simple arrangement, which consists of a box with a plate of glass in the bottom. You put this in the water, so that the glass is a few inches below the surface, and then you can see very clearly, where the depth is not too great. Fishermen in some parts of the world have something of the same nature, which they call a telescope; it is nothing but a tube of wood four or five feet long, and six inches in diameter, and with the top so arranged that when the eye is put against it there can be no entrance of light at that end of the tube. When a man wishes to examine the bottom of the sea where he is fishing, he sinks this tube and looks through it. He can make out many objects that are altogether invisible under ordinary circumstances, and can frequently discover the whereabouts of a school of fish that might otherwise escape him.
SUBMARINE OBSERVATIONS.
"Sometimes a man who is using one of these aids to marine observation finds himself the object of attentions he would gladly avoid. A friend of mine was once looking through a box from the side of a boat, when a large sawfish came from below and thrust his snout through the glass. A shark followed the sawfish, and was evidently anxious for a fight, and the two swum off together, to the satisfaction of my friend. What made the matter more exciting was that an expert swimmer had just dived from the boat, and gone down to take a survey of the coral-trees that grew on the bottom. He came up safe and undisturbed, and the probabilities are that the sawfish and shark had been too busy over each other and the glass-bottomed box to pay any attention to such an insignificant object as a man swimming near them.
THE BELLOWS-FISH, OR ANGLER.
"The bottom of the sea abounds in many curious things that we never see at the surface, unless they are brought there. There is a fish known as the Lophius, or bellows-fish; he is also called 'the angler,' from his artistic way of supplying himself with food. He seems to be nearly all mouth, and reminds you of the dog that could walk down his own throat without touching the sides. He has a long rod projecting from the middle of his forehead, and at the end of it there is a lump of flesh, like a morsel of beef. This rod is movable; and, as he lies flat on the mud, he spreads his great mouth open like a trap. Then he angles, or fishes, with his rod, moving it up and down and on both sides, so as to attract fish or crabs, or anything else that is edible. When they come within reach of his capacious jaws he closes on his prey, and goes on with his fishing as unconcerned as a man who has caught a small trout, and stowed it away in his basket."
The boys laughed at the idea of an angling fish, and wondered how he managed to get along when he had lost his bait by any accident. The captain was unable to tell them, as he had never seen a bellows-fish that had suffered such a misfortune.
A CURIOUS HOME.
"You see thousands of crabs and lobsters and other creeping things at the bottom of the sea," the captain continued; "there is one kind of crab that loves to live in a shell which is not his own, at any rate not the one he was born to. They crawl around with these shells, never daring to leave them for fear some other crab will happen along and take possession. Sometimes two of them will fight for a shell, and they tear away each other's claws and commit other havoc before the battle is over. Generally the one in the shell has the best of it, as he is on the defensive, and the house in which he is lodged is a good protection. One day I found one of these crabs in the bowl of a tobacco-pipe that had the stem broken short off, and it was very funny to see him move around with this awkward covering. It was not as convenient as the sea-shells in which his brethren were quartered, and he seemed to understand it, as he changed to an empty shell as soon as one was placed near him, and he was left undisturbed.
CRABS IN A QUARREL.
"These crabs are amphibious, and seem equally at home above or under the water. They are very quarrelsome, and when put together in a box proceed to eat each other up without the least hesitation. I once put a dozen of them together, and in two days there was only one left; he was large, and had a good appetite, as he left nothing but shells and crushed claws to tell what had become of his comrades.
"But we have been so long beneath the surface that we must go above to breathe. As we come up we must be careful not to touch one of those long filaments hanging down from the Physalia that has spread its sail to the wind. If we do, we shall feel a sharp sting that will last us for some time."
Frank inquired what the Physalia was.
"You have seen it very often at sea," said Captain Johnson, "and probably you knew it as a Portuguese man-of-war."
"Oh, certainly," Frank answered. "We saw thousands and thousands of them on the Pacific Ocean when we were coming from San Francisco, and sometimes the water was covered with them for hours at a time. And they looked very pretty, with their little sails spread to catch the wind."
"What you saw above the surface was not really a sail," the captain replied, "but a little sack containing air. The Physalia has the power of contracting this sack, so that it can sink beneath the waves for protection against a storm or to avoid other dangers. The use of the long filaments is not well understood; but they are evidently for purposes of defence, as each of them contains a sting that has anything but an agreeable effect on the swimmer who comes in contact with it."
Fred asked if the Physalia was anything like the sea-anemone which he had seen in Aquarius, and had admired greatly on account of its beautiful colors.
"How many colors of it do you think you have seen?" the captain asked, in reply.
SEA-ANEMONES.
Fred could not say positively, but he thought he had seen not less than three or four.
"They are of every color imaginable," responded Captain Johnson; "we find them white, with a delicate shading of pearl, and we have them in gray, pink, purple, yellow, orange, lilac, green, and blue. Sometimes a single specimen will have half a dozen colors in his composition, and you could easily imagine he had borrowed all the hues of the rainbow in getting himself up to a satisfactory complexion. They have the properties of both animal and vegetable, and in this particular they resemble the sponge and other marine productions. If a part of the sea-anemone is destroyed, it is reproduced; and if one of them is torn or cut into several pieces, each piece converts itself into a perfect anemone."
"Is the sponge an animal?" Frank asked of the captain. "You said something about the sea-anemone having animal and vegetable properties like the sponge. I always supposed the sponge was a vegetable growing at the bottom of the sea, and had nothing of the animal about it."
"Scientific men have long been in dispute on this subject," was the reply; "and while some assign the sponge to the vegetable kingdom, others class it with the animal. The latest authorities favor the theory that the sponge is an animal, and all agree that it occupies a middle ground between the two forms of life.
THE SPONGE AT HOME.
"It is fastened to a rock, or to the hard bottom of the part of the sea where it grows, and it has no power of moving from one place to another. Water is continually absorbed into the sponge, just as we absorb air by breathing; and when the food and air contained in the water have served their purpose, the residue is thrown off.
"The sponge has a skeleton that must be dissolved and washed away before the article is of use. Various processes are used to remove the skeleton—according to the character of the sponge and the purposes for which it is designed. The finest are washed repeatedly in water, and in a weak solution of acid, and are then bleached in a bath of diluted soda. These fine sponges come from Syria, and from the Greek islands of the Mediterranean; the coarse sponges, used for washing carriages and similar purposes, come from the West Indies, and also from the East; and when first taken from the sea they have a sickening odor, like flesh that is just beginning to decay. This odor becomes stronger and stronger, and finally resembles exactly that which arises from a putrefying body. During this process of decomposition they are buried in the sand, and are afterwards submitted to the action of the waves to wash away the impurities that the decay has left."
One of the boys asked how sponges were obtained, and at what depths of water they were to be found.
HOW SPONGES ARE SPEARED.
The captain explained that they were found at all depths, from a few feet to two or three hundred. The most of them were taken from shoals and reefs, where they were ten or twenty feet below the surface, as they could not get a good supply of light in deeper water. In the East they are generally taken by diving, after the primitive fashion; while in the West Indies they are speared from boats.
"But we started out to talk about pearls," said Captain Johnson, "and we have wandered off to several other things. Suppose we go back to pearls, and see what we can ascertain about them."
The boys promptly agreed to this; and Frank was evidently determined to begin at the beginning, as he referred to the pearl which Cleopatra was said to have dissolved in vinegar, so that she might swallow a more costly drink than had ever been known to anybody else.
"That was more than eighteen hundred years ago," said Fred, "and perhaps the incident never happened."
CLEOPATRA DISSOLVING THE PEARL.
Captain Johnson was uncertain about it, as he said he had no documentary proof sufficient to convince an ordinary court of law that dissolved pearls were a fashionable beverage in the days of Antony and Cleopatra. "However," he said, "the pearl can be dissolved in strong vinegar; and this fact is sufficient to establish the possibility of the beautiful Queen of Egypt indulging in the freak that is attributed to her.
"Pearls have been known and valued for a great many hundred years. They are mentioned in the Bible, and in the time of Job they were great price. The Greeks and Romans had great numbers of pearls, and some of the wealthy citizens were in the habit of wearing them on their shoes. In all ages they have been associated with wealth, and probably they will continue to be for ages to come.
PEARL-BEARING SHELLS.
"The oyster that produces them is not good to eat; probably he thinks he has quite enough to do to make pearls, without being devoured after he has performed that noble duty. They are found in various parts of the world; but the best pearls have always come from the East: they are valuable in proportion as they possess that peculiar lustre known as 'water,' which it is impossible to describe in words. There are several varieties of the pearl-oyster, but the best of them is of a nearly circular form, and from four to eight inches in diameter. Here is a picture of one of these shells, with a single pearl adhering to it. The outside of the shell is rough, and has a series of ridges that extend from the valve to the edge. The young oysters rarely contain pearls; and the divers understand this so well that, when they find smooth-shelled and small oysters in their baskets, they throw them back into the sea. In the haste of gathering them from the rocky bottom, they have no time to select with care.
"The pearl is nothing more nor less than carbonate of lime, secreted by the oyster, and hardened after a process which he carefully keeps to himself. It was for a long time supposed that the pearl was formed by the attempt of the oyster to cover a grain of sand with a smooth substance, so that it would not be inconvenient to him. It was believed that the sand was rolled in by the action of the waves while the oyster had his mouth open; and, as he could not expel it, he proceeded to cover it up. Many persons adhere to this theory still; but the fact that many pearls have been sawed open and found not to contain the least particle of sand or other impurity, is calculated to throw doubt upon it. The latter belief is, that the pearl is the result of a disease in the oyster, just as a tumor is the result of disease in man.
"In China and Japan the natives have long followed the practice of putting small beads of porcelain inside the oyster, and then returning him to the water, where he is left undisturbed for three or four years. At the end of that time he is taken up and opened, and the beads are found to be coated with the pearly substance. They also have the trick of putting little images or idols into the oyster, and in course of time these become coated over in the manner I have described. You can see some of the results of these processes by looking at the two open shells on the right of the picture."
Frank wished to know the different sizes of pearls and their values.
SIZES OF PEARLS.
"As to that," said the captain, "your question is not an easy one to answer. Some pearls are so small as to be hardly visible to the eye; and of course they are of no value when you cannot see them. They are only useful when large enough to be strung on a necklace, or otherwise set as jewellery. The largest pearls are apocryphal; by this I mean that no person of modern times has seen some that are famous in history, and there are doubts that they ever existed. It is said that the pearl which Cleopatra drank to the health of Mark Antony was worth $375,000 of our money; and, if so, it must have been of great size. Pearls have been reported to exist that were nearly two inches long by one and a quarter in diameter, and weighed fifty-five carats, or two hundred and twenty grains.
"The largest that we know of at the present time do not exceed thirty carats, or one hundred and twenty grains. There is one among the crown-jewels of Portugal weighing twenty-five carats; and there is said to be one of twenty-seven carats in the hands of a Russian merchant in Moscow. It is safe to say that there are not two dozen pearls known to exist now that weigh over twenty carats, or eighty grains.
"The value of a pearl is generally estimated like that of a diamond—by the multiplication of the square of its weight. A pearl of one carat is held to be worth about $16; and to get the value of a pearl of two carats we multiply two by two, and the product by $16, and we get $64. In the same way the value of a pearl of three carats would be $144, and so on for any weight we happen to have.
PEARL-FISHERY AT BAHREIN.
"One of the favorite fishing-grounds for pearls is at Bahrein, on the Persian Gulf. The divers bring in the oysters from the fishing-banks in the gulf, and pile them on the shore in great heaps. Here they lie till they are rotted; and the stench that arises is enough to turn any inexperienced stomach. When the substance of the oyster is quite decomposed, the shells are opened, and the mass of matter they contain is thrown into tubs and washed with water. It is necessary to pass the pulp very carefully through the fingers for fear that some of the pearls will be lost, and consequently the washing is very slow. When a pearl beyond a certain size is found, the washer receives a handsome present; but below the regulation figure he gets nothing but his daily wages. Large pearls are very rare, and consequently the chances that a pearl-washer will make a fortune by a lucky find are exceedingly small.
PERSIAN GULF DIVER.PERSIAN GULF DIVER.
"There is a belief quite current through the East that the pearl is a drop of rain-water which has fallen into the shell of the oyster when he was at the surface, and been afterwards hardened. This is a pretty bit of sentiment; but as the oyster never goes to the surface unless he is carried there, the story does not have much foundation to rest upon."
"If the pearl is so valuable, and so difficult to get, I should think there would be men who would try to imitate it," Frank remarked.
"You are quite right," was the reply; "and men have tried a great many times to make false pearls."
"Have they succeeded?"
"Partially; but not altogether. No counterfeit pearl has yet been made that could pass all the tests of the genuine; but their lustre is quite equal, sometimes, to the best pearls of Ceylon, and they can be made to deceive anybody but an expert."
"How do they make them?"
"The best of the false pearls," said the captain, "are made by what is known as Jaquin's process.
"M. Jaquin was a manufacturer of beads in France, and he spent a great deal of time and money in trying to make his beads better than any other man's. One day he was walking in his garden, and observed a remarkable silvery lustre on some water in a basin. It instantly occurred to him that if he could put that lustre on his beads, he would have something decidedly new.
"So he called his old servant, and asked what had been in the water. She answered that it was nothing but some little fish called ablettes, that had been crushed in the basin, and she had neglected to throw the water out.
M. JAQUIN'S EXPERIMENT.
"M. Jaquin was very glad, for once, that she had neglected her duty. He began experimenting with the scales of the ablette, or bleak, a little fish about the size of a sardine, and very abundant in certain parts of Europe. After several trials he adopted the plan of washing the scales several times in water, and saving the sediment that gathered at the bottom of the basin. This was about the consistency of oil, and had the lustre he desired. Next, he blew some beads of very thin glass, and after coating the inside of a bead with this substance, he filled it up with wax, so as to give it solidity. Thus the fish-scales gave the lustre, the glass gave the polish and brilliancy that we find on the genuine pearl, and the wax furnished a solid backing to the thin glass. This is the process of making false pearls; and it is fortunate that the bleak is very abundant, or he would run the risk of extermination.
THE BLEAK.
"Is the manufacture of false pearls so great as that?" Fred inquired.
"It is pretty extensive," was the captain's response, "but not enormously so. The fact is, it requires more than a thousand of these little fish to make an ounce of the 'essence d'orient,' as the French call it, or essence of pearl. Other substances have been tried, in the hope of obtaining the same result for a smaller outlay, but none of them have been entirely successful. There is—"
The conversation was interrupted at this moment by a call from the Doctor, who was sitting near the rail, and happened to be looking at the sea. The rest of the party rushed to his side, and their eyes followed the direction indicated by his finger.
THE DOCTOR'S DISCOVERY.
The object that attracted his attention was an enormous turtle not more than ten yards away. He appeared to be asleep, as he was lying perfectly still, and did not seem aware that a ship was near him. Suddenly he roused himself, and raised his head an instant above the surface to take a survey of the situation. Evidently he scented danger, as he lost no time in diving below, where the ship was not likely to follow him.
Pearls were dropped from the conversation, and turtles took their place. As the turtle is a product of the sea, the subject was not likely to be an unknown one to Captain Johnson.
"There are several varieties of the marine turtle," said the captain, "and more of the land-turtle, or tortoise; as we are at sea, and engaged on matters connected with salt-water, we will leave the occupant of the land quite out of consideration. His marine brother has fins instead of feet, and he rarely goes on shore except in the breeding-season. Some of the sea-turtles live entirely on vegetable food, while others devour shell-fish and other living things; the flesh of the vegetable-feeders is delicious, while that of the animal-feeders is not. They grow to a great size when compared with the land-turtle: the green turtle that makes such excellent soup is frequently five feet long, and weighs five or six hundred pounds; and the loggerhead-turtle sometimes reaches a weight of one thousand five hundred pounds and more."
"Enough to feed a great many people," Frank remarked.
"Unfortunately," the captain continued, "a great many people would not eat his flesh. The green-turtle feeds on sea-weed, and is very choice about what he eats, and therefore his flesh is highly esteemed. The loggerhead-turtle is much more common than the green one, but he eats shell-fish of all the sorts he can crush in his powerful jaws. The flesh of the young turtles of this variety is sometimes eaten, but the old ones are so tough and musky that a man must needs be very hungry to be able to eat them. Even their eggs are too strong of musk to be edible, and the shell is of little value; about the only use that can be made of the loggerhead-turtle is to try out the large quantities of oil that he contains.
"The flesh of the turtle you just saw is not of much consequence, for the same reason. He is more valuable for his shell, which forms the turtle, or tortoise, shell of commerce."
"I remember," said Fred, "that we saw a great deal of shell at Nagasaki, in Japan, that had been wrought into many beautiful forms. The Japanese are very skilful in this kind of work, and so are the Chinese."
"You will see more tortoise-shell," was the reply, "when you get to Singapore. A great deal of the shell comes there for a market from all parts of the Eastern Archipelago."
Frank asked how the turtle was caught, when he spent so much time in the water, and was so far away from land.
"He is caught," said the captain, "in two or three ways. He sleeps on the surface of the water, and, when thus off his guard, he can be easily approached. A boat steals quietly up to him, and, before he is aware what is happening, he is a prisoner.
THE TURTLE AT HOME.
"Turtles are captured at night, when they go on shore to lay their eggs. They generally select a moonlight night for this purpose, and a smooth sandy beach; they dig holes in the sand, where they deposit their eggs, and leave them to be hatched by the heat of the sun. When they are on shore for this purpose, the hunters come upon them; the turtle cannot move rapidly on the sand, and is easily overtaken. The hunters turn the poor turtles on their backs, and then leave them till the next day, when they come and remove them."
"I have heard," said one of the boys, "that when a turtle is placed on his back he cannot turn over and put himself right side up."
"That is quite correct, and a knowledge of this peculiarity is of great assistance to the turtle-hunters. But there is another way of catching the turtle that will strike you as the most curious of all."
"What is that?"
"It is by fishing with the Remora."
"And what is the remora?"
"It is a fish found in tropical waters, both in the East and West Indies. Its popular name is 'the sucking-fish,' and it is so called on account of a disk on its head, by which it can attach itself to a smooth surface, like the side of a shark, a ship, or the shell of a turtle. The disk is very much like the soft leather 'suckers' made by school boys, and when the fish has attached himself, you can pull him to pieces rather than induce him to release his hold.
"The turtle-hunters go out in a boat and carry several of these fishes in a tub. When they see a turtle they get as near to him as they can, and send a sucker after him. The fish is held by a ring on his tail, attached to a stout cord; he swims towards the turtle and fastens on his shell, and then the fish and turtle are hauled in together. In the air the remora loosens his hold, and is dropped back into the tub, to wait till he is wanted again."
The boys laughed at this comical way of fishing. Fred wondered if the remora was able to understand the joke, and comprehend the value of his services to mankind. Frank said he would like to know what the turtles thought of the business, and whether they had any respect for a parasite that came uninvited and caused them to be captured.
TURTLE-HUNTING.