Show globular lightning 11 ll lightning balls are comparatively rare phenomena although there are many recorded instances jub of their appearance pe arance during thunderstorms tho the cause of their for formation M atto a Is more or less it ii mystery but some light has been thrown upon lipon it recently by the experiments of signor signer right at bologna ile he has succeeded in producing aroln arbili cial lightning balls with a powerful holtz electric machin enild and a battery of leyden jars and has mails made photographs of them in various stages ot of their existence the conditions under which lie hp produces his mimic lightning are arc high resistance in the di discharging 8 circuit great capacity in the condet conweiser con deiser ser and a rarefaction ot of tho the air through which the discharge takes place |