LIGHTNING’S SECRET

Nelson Evening Mail, Volume LXVI, 21 April 1934, Page 2

LIGHTNING’S SECRET

Remarkable discoveries, hitherto unsuspected, about the nature and behaviour of lightning have been made with a simple camera invented by Dr. Charles Vernon Boys, past president of the Physical Society of London and of the Rontgen Society. Photographs obtained with such a camera, which has two lenses revolving on a disc, reveal that the preliminary to a flash proper is what may be. described as “a dart of light,” only a few yards long. It shoots from a cloud to the earth at the comparatively slow speed of one-thirtieth of the speed of light (which is 186,325 miles a second). As soon as it reaches the earth a return Hash of a totally different kind passes back along the same track to the cloud. The return Hash is much longer than the dart: it may occupy half th e distance between the earth and the cloud.. It also travels much quicker—about one-quarter of the speed of light. After an interval of about one-two-hun-dredth of a second the whole procedure is repeated, and it may be repeated a number of times. The dart is invisible to the human eye, and it is the brightly luminous return flash which is actually seen.