LIGHTNING, THUNDER AND LIGHTNING CONDUCTORS. _WITH AN APPENDIX ON THE RECENT CONTROVERSY ON LIGHTNING CONDUCTORS._ BY GERALD MOLLOY, D. D., D. Sc. _ILLUSTRATED._ [Illustration] NEW YORK: THE HUMBOLDT PUBLISHING CO., 28 LAFAYETTE PLACE. LIGHTNING, THUNDER, AND LIGHTNING CONDUCTORS. CONTENTS. LECTURE I. Pages 5-26 LIGHTNING AND THUNDER. Identity of Lightning and Electricity--Franklin’s Experiment--Fatal Experiment of Richman--Immediate Cause of Lightning--Illustration from Electric Spark--What a Flash of Lightning Is--Duration of a Flash of Lightning--Experiments of Professor Rood--Wheatstone’s Experiments--Experiment with Rotating Disc--Brightness of a Flash of Lightning--Various Forms of Lightning--Forked Lightning, Sheet Lightning, Globe Lightning--St. Elmo’s Fire--Experimental Illustration--Origin of Lightning--Length of a Flash of Lightning--Physical Cause of Thunder--Rolling of Thunder--Succession of Peals--Variation of Intensity--Distance of a Flash of Lightning LECTURE II. Pages 26-53 LIGHTNING CONDUCTORS. Destructive Effects of Lightning--Destruction of Buildings--Destruction of Ships at Sea--Destruction of Powder Magazines--Experimental Illustrations--Destruction of Life by Lightning--The Return Shock--Franklin’s Lightning Rods--Introduction of Lightning Rods into England--The Battle of Balls and Points--Functions of a Lightning Conductor--Conditions of a Lightning Conductor--Mischief Done by Bad Conductors--Evil Effects of a Bad Earth Contact--Danger from Rival Conductors--Insulation of Lightning Conductors--Personal Safety in a Thunder Storm--Practical Rules--Security Afforded by Lightning Rods APPENDIX. Pages 55-62 RECENT CONTROVERSY ON LIGHTNING CONDUCTORS. Theory of Lightning Conductors Challenged--Lectures of Professor Lodge--Short Account of his Views and Arguments--Effect of Self-Induction on a Lightning Rod--Experiment on the Discharge of a Leyden Jar--Outer Shell only of a Lightning Rod Acts as a Conductor--Discussion at the Meeting of the British Association, September, 1888--Statement by Mr. Preece--Lord Rayleigh and Sir William Thomson--Professor Rowland and Professor Forbes--M. de Fonvielle, Sir James Douglass, and Mr. Symons--Reply of Professor Lodge--Concluding Remarks of Professor Fitzgerald, President of the Section--Summary Showing the Present State of the Question LIST OF ILLUSTRATIONS. PAGE THE ELECTRIC SPARK: A TYPE OF A FLASH OF LIGHTNING, 8 CARDBOARD DISC WITH BLACK AND WHITE SECTORS; AS SEEN WHEN AT REST, 12 SAME DISC; AS SEEN WHEN IN RAPID ROTATION, 12