The time came when the child had to leave this nursery to enter school, but always, when the day's session was over, she went directly to that other school where she listened fascinated to all her father taught about the wonders of the inner world of atoms and the mysterious forces that make the visible world in which we live. She still believed in fairies,--oh, yes!--but now she knew their names. There were the rainbow fairies--light-waves, that make all the colors we see,--and many more our eyes are not able to discover, but which we can capture by interesting experiments. There were sound-waves, too, and the marvelous forces we call electricity, magnetism, and gravitation. When she was nine years old, it was second nature to care for her father's batteries, beakers, and retorts, and to help prepare the apparatus that was to be used in the demonstrations of the coming day. The students marveled at the child's skill and knowledge, and called her with admiring affection "professorowna," (daughter-professor). There was a world besides the wonderland of the laboratory, of which Marie was soon aware. This was the world of fear, where the powers of Russia ruled. In 1861 the Poles had made a vain attempt to win their independence, and when Marie was a little girl (she was born in 1867), the authorities tried to stamp out any further sparks of possible rebellion by adopting unusually harsh measures. It was a crime to speak the Polish language in the schools and to talk of the old, happy days when Poland was a nation. If any one was even suspected of looking forward to a better time when the people would not be persecuted by the police or forced to bribe unprincipled officials for a chance to conduct their business without interference, he was carried off to the cruel, yellow-walled prison near the citadel, and perhaps sent to a life of exile in Siberia. Since knowledge means independent thought and capacity for leadership, the high schools and universities were particularly under suspicion. Years afterward, when Marie spoke of this reign of terror, her eyes flashed and her lips were set in a thin white line. Time did not make the memory less vivid. "Every corridor of my father's school had finger-posts pointing to Siberia!" she declared dramatically. When Marie was sixteen, she graduated from the "gymnasium" for girls, receiving a gold medal for excellence in mathematics and sciences. In Russia, as in Germany, the gymnasium corresponds to our high school, but also covers some of the work of the first two years of college. The name gymnasium signifies a place where the mind is exercised and made strong in preparation for the work of the universities. The position as governess to the daughters of a Russian nobleman was offered to the brilliant girl with the sweet, serious eyes and gentle voice. As it meant independence and a chance to travel and learn the ways of the world, Marie agreed to undertake the work.