The Advance in Electricity Since the Time of Franklin (Paperback)

Purchase of this book includes free trial access to www.million-books.com where you can read more than a million books for free. This is an OCR edition with typos. Excerpt from book: CHAPTER III PROTECTION FROM LIGHTNING WHEN we enter upon a scientific examination of one of the greatest manifestations of energy in nature, we naturally think first of Benjamin Franklin. His dramatic act in drawing lightning from the clouds is related to every school boy; but few Americans know the bearing of Franklin's theory of electricity upon the electron theory which now prevails: this bearing I hope to make clear. In the first place, let us examine the prevailing views and superstitions of the common man in regard to lightning and his attitude toward the lightning rod. It is now one hundred and seventy odd years since Franklin advocated the use of pointed rods to draw electricity from the clouds, and Dalibard tried an experiment with such rods in Paris. Franklin did not wait for the erection of a rod in Philadelphia but flew a kite provided with a metallic point, and held by an ordinary pack thread, during a thunder storm. At the end of the pack thread a silk thread and a key were attached: the silk thread was attached to a tree. For a time no effect was observed, and Franklin began to despair of success; presently, however, the string being wet, he presented his knuckles to the key and received a spark. Thus was made the most renowned experiment in electricity. Perhaps he got merely a wireless message from a distant lightning flash, for the kite and string may have served as an aerial for a pulsating inductive effect: indeed sucheffects occur during thunder storms on telegraph and telephone wires. I mention this as a possible interpretation of the result he obtained, but not to belittle his achievement. If he did not actually draw down lightning from the clouds he proved the identity of atmospheric electricity with that furnished by electrical machines. The simplicit...