LIVING SILVER.

BY MARY H. SEYMOUR.

The ground was covered with snow, and now it had begun raining. There was no prospect of a change in the weather, which made Fred's face rather gloomy as he looked out of the window. Harry was turning over the leaves of a story-book. You could see they were both disappointed that the morning was stormy; for when they came to grandpapa's in the winter, they expected bright days and plenty of fun.

"What shall we do?" said Fred.

"Let's go into the garret!" exclaimed Harry.

This plan evidently suited both of them, for they made a rush toward the door; and the dog, awakening from his nap, entered into the idea, too.

At this moment, Aunt Carrie came into the room. They wished it had been grandmamma, for she never laid the least restriction on their sports, but smiled on every request and allowed them to do exactly as they pleased.

"Now, boys," said Aunt Carrie, "where are you going?"

"Only into the garret, auntie."

"Be sure to leave things exactly as you find them," she replied, with a laugh and a little groan.

"We always do, Aunt Carrie."

Away they went, with Gyp at their heels, and every footstep resounded through the old house until they reached the upper floor.

"It is no wonder that garret is never in order," said Aunt Carrie; "but the children must enjoy themselves."

"Of course, they must, Carrie," replied grandma from the depths of her heart.

First, the boys pulled out a box of old books and papers, and busied themselves reading the queer names and advertisements of old times. Soon they turned from these to a shelf of chemical instruments. Most of them were in perfect order, and they knew they must keep their hands off, for the bulbs and tubes of glass were too delicate to be touched by unskilled fingers.

"Here is an old broken forrometer," exclaimed Harry. "Let's ask grandpa if we can have it."

"You mean thermometer, don't you?" said Fred. "What can we do with that?"

"Don't you see? There is a great deal of quicksilver in this glass ball, and we can play with it. I'll show you how." And away they went downstairs to find their grandfather.

"Grandpa, can we have this?"

Mr. Lenox looked up from his newspaper.

"Let me see it a moment. What do you wish to do with it?"

"We will break it and take out the quicksilver, and then I will show you. Let me ask Ellen for a dish to catch the drops."

"Not quite so fast; wait a moment, Harry," replied Mr. Lenox. "I wish you to notice something about it first. The top of the tube is slightly broken, which makes it of no exact use, for to measure heat or cold the quicksilver must be entirely protected from the air. If you had noticed it when you first came in, you would see that the warmth of the room has caused it to rise in the tube. This is shown by the marks on the plate to which it is fastened. Now, if you hold it close to the stove, the quicksilver will rise still higher. Let it stand outside the window a moment, and it will sink."

By this time the boys were much interested.

"But what makes it do so, grandpa?" they asked.

"Quicksilver is very sensitive to heat and cold. If the weather is warm, or if the room it is in is warm, it expands—swells out—and so rises in the glass tube, as you have seen. The least coolness in the air will cause it to contract, or draw itself into a smaller space; then, of course, it sinks in the tube.

"The barometer is another instrument in which quicksilver is used. It is intended to measure the weight of the air, therefore the quicksilver in it must be exposed to the pressure of the air. Common barometers have it inclosed in a small leather bag at the back of the instrument. This we do not see, but only the tube which is connected with it. When the weather is pleasant, the air, contrary to the general idea, being heavier, presses against this little bag and the quicksilver rises in the tube. When the atmosphere is damp, the pressure being less, the metal sinks."

"Grandpa," said Harry, "when you think of it, isn't quicksilver a funny word?"

"Yes; it was so named by people who lived many hundreds of years ago. They called it living silver also. It is the only metal found in a liquid state; and so many strange changes did it pass through under their experiments, that it seemed to them really a living thing. If they tried to pick it up, it would slip out of their fingers. When thoroughly shaken, it became a fine powder. They boasted that it had the faculty of swallowing any other metal, while powerful heat caused it to disappear entirely. It is now known among metals as mercury. Can you tell me, Fred, some of the metals?"

"Oh yes, sir! There are gold, silver, iron, lead and copper."

"That is right. But, you know, all these are hard; some of them can be chipped with a knife, but they cannot be dipped up in pails, unless they have first been melted. Yet mercury can be frozen so hard that it may be hammered out like lead, and sometimes it takes the form of square crystals. Yet it can be made to boil, and then sends off a colorless vapor."

"Grandpa." said Fred, who had scarcely listened to the last words, "if mercury can be dipped up in pails, it must be very easy to get it. I read somewhere that gold and silver are so mixed in with the rock that it takes a great deal of time and money to separate them."

"That is true; but mercury is not always obtained easily. It forms part of a soft, red rock called cinnabar, composed of mercury and sulphur. The cinnabar is crushed and exposed to heat, when the metal, in the form of vapor, passes into a vessel suited to the purpose, where it is cooled. Then, being reduced to its liquid state, it is pure and fit for use. When men working in the mines heat the rocks, the quicksilver will sometimes roll out in drops as large as a pigeon's egg, and fall on the ground in millions of sparkling globules. Think how very beautiful it must be, the dark red rock glittering on every side with the living silver, while every crack and crevice is filled with it!

"Visitors to the mines of Idria are shown an experiment that I think would interest you boys. In large iron kettles filled with mercury are placed huge stones, and these stones do not sink."

"Why, grandpa! how can that be?"

"Did you ever see wood floating on water?"

"Yes, sir, but that is different."

"But the principle is the same; can you tell me why?"

Both the boys looked puzzled.

"It is only because the wood does not weigh so much as water; neither are the stones as heavy as mercury, therefore they cannot sink."

"I wish we could go into the mines. Can't you take us, sometime, grandpa?" said Harry.

"That is asking rather too much, my child, for quicksilver is not a common metal. There are in the world only four important localities from which it is obtained. These are California, Peru, Austria, and Almaden in Spain. The mines nearest us are in California. I think I shall never go as far as that, but I hope you both may before you reach my age.

"It is a curious story how the mines in Peru were discovered. Cinnabar, when ground very fine, will make a beautiful red paint. The Indians used this to ornament their bodies on grand occasions. This caused the country where they lived to be examined, and the cinnabar was found. The Romans used this paint hundreds of years ago in decorating their images and in painting pictures. It is very highly valued now, and we call it vermilion."

"Fred," continued Mr. Lenox, "you spoke of the difficulty of separating gold and silver from the rock in which they are found. Did you know that our wonderful mercury renders valuable aid in this? The rock that contains the precious metal is crushed fine, sifted and washed until as much as possible of the gold or silver is removed; then it is placed in a vessel with the quicksilver, which seems immediately to absorb it, thus separating it entirely from every particle of sand or rock. If the metal to be cleansed is gold, you will see a pasty mass or amalgam, as it is called, of a yellowish tinge. This is heated, and the mercury flies away, leaving behind it the pure gold."

"How did people learn to do this?" asked Fred.

"They did not learn it all at once. It was only by years of patient effort and frequent failure that they finally succeeded.

"You know there are many gold and silver mines in California," continued grandpa. "Near some of them large mines of quicksilver have been discovered. You can imagine that this caused great rejoicing, for all the quicksilver previously used was sent in ships to this part of the world, which, of course, made it scarce and very expensive. Now, we can send away quantities to other countries after supplying our own wants.

"Notwithstanding that this strange metal renders such service to mankind—for I could tell you of many other useful things it does—it is a deadly poison. Its vapor is so dangerous that persons searching for it often die from breathing the air where it is found. About seventy years ago, the mines in Austria, took fire, and thirteen hundred workmen were poisoned, and many of them died. The water that was used to quench the fire being pumped into the river Idria, all the fish died excepting the eels. Since that time, spiders and rats have deserted the mines.

"Mercury is carried in sheepskin bags and cast-iron bottles. It is so heavy that an ordinary cork would soon be forced out by it, therefore an iron stopper must be screwed in.

"Once, some bags of mercury were stored in the hold of a foreign vessel; unfortunately, a few of the bags were rotten and leaked. Every person on board was poisoned, and every piece of metal connected with the vessel received a silvery coating of mercury."

"It is dreadful! Fred, don't let us touch it," said Harry.

"Don't be frightened yet, Harry. Did you know that mercury is used as a medicine? It is given in very small doses."

"I am sure I shall never take it," exclaimed Fred.

"Perhaps you may have done so already," replied their grandfather, laughing. "Did you ever hear of blue-pill and calomel? They both are preparations of mercury."

Just then the sun shone into the room so brightly that every one turned to the windows. Such a sparkle! The evergreens were covered with shining ice-drops, and the tall trees pointed their glistening branches toward the few clouds that were hurrying over the blue sky.

"I am not sorry it rained, after all," said Fred. "I have enjoyed the morning so much that I forgot the play we were going to have."

Two happy, tired boys went to sleep that night, and the next morning they started for home. They both agreed in thinking they had never enjoyed a more delightful visit at grandpapa's.