Ermák took with him fifty men and went out to clear the road for the Bukhara merchants. He came to the Irtýsh River, but did not find the Bukharans. He remained there over night. It was a dark night, and it rained. The Cossacks had just lain down to sleep, when suddenly the Tartars rushed out and threw themselves on the sleepy men and began to strike them down. Ermák jumped up and began to fight. He was wounded in the hand. He ran toward the river. The Tartars after him. He threw himself into the river. That was the last time he was seen. His body was not recovered, and no one found out how he died. The following year came the Tsar's army, and the Tartars were pacified. NATURAL SCIENCE STORIES 1869-1872 NATURAL SCIENCE STORIES STORIES FROM PHYSICS THE MAGNET I. In olden days there was a shepherd whose name was Magnes. Magnes lost a sheep. He went to the mountains to find it. He came to a place where there were barren rocks. He walked over these rocks, and felt that his boots were sticking to them. He touched them with his hand, but they were dry and did not stick to his hand. He started to walk again, and again his boots stuck to the rocks. He sat down, took off one of his boots, took it into his hand, and touched the rocks with it. Whenever he touched them with his skin, or with the sole of his boot, they did not stick; but when he touched them with the nails, they did stick. Magnes had a cane with an iron point. He touched a rock with the wood; it did not stick; he touched it with the iron end, and it stuck so that he could not pull it off. Magnes looked at the stone, and he saw that it looked like iron, and he took pieces of that stone home with him. Since then that rock has been known, and has been called Magnet. II. Magnet is found in the earth with iron ore. Where there is magnet in the ore, the iron is of the best quality. The magnet resembles iron. If you put a piece of iron on a magnet, the iron itself begins to attract other iron. And if you put a steel needle on a magnet, and hold it thus for awhile, the needle will become a magnet, and will attract iron. If two magnets are brought together at their ends, one side will turn away from the other, while the other sides will be attracted. If a magnetic rod is broken in two, each half will attract at one end, and will turn away at the other end. Cut it again, and the same will happen; cut it again, as often as you please, and still the same will happen: equal ends will turn away from each other, while opposite ends will be attracted, as though the magnet were pushing away at one end, and pulling in at the other. No matter how you may break it, it will be as though there were a bump at one end, and a saucer at the other. Whichever way you put them together,--a bump and a saucer will meet, but a bump and a bump, or a saucer and a saucer will not. III.