1. Lightning is caused by the friction of vapor, which is at a suitable temperature. Thus two or more currents of air coming together will cause lightning, as the friction concentrates the electricity, and as there is no conductor the heavy voltage flies usually toward the nearest conductor. This voltage is so great that it explodes the air. The air coming together again produces a great vibration, called thunder. 2. Aurora Borealis. The outer circle around the earth represents atmosphere. The sun current carries it far from the earth's surface. At the north, when the sun's reflection strikes the earth's crust in such a manner, its reflection will be seen in the atmosphere at a great height, called Northern Lights. This is mostly seen in November, December, and January. [Figure: Uncaptioned line drawing (accompanying the paragraph above) of the Earth's orbit about the sun.] 3. The museum of Alexandria was established about 400 years B.C., for the purpose of restoring science that had been lost thousands of years before. The cultivation of knowledge by experiment, observation, and mathematical discussions: this was the birth of a science of to-day. The library contained many thousands of volumes of books, but was destroyed by Cyril; a girl in charge of the library by the name of Hypatia was brutally killed and the flesh was scraped from her bones with sea shells. This occurred in 414 A.D. Alexander died at Babylon 323 B.C. China, Mesopotamia, and India had made astronomical observations at this early date. Most of these learnings were destroyed. Brono, Isaac Newton, Brably, and some few others, promoted science by their discoveries of what is to-day. "Good Will to man."