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SCIENCE 



[N. S. Vol. XXX. No. 781 



ment, that it is difficult to escape the con- 

 clusion that there in reality exists this rare 

 form of electric effect, globular lightning. 

 We can not properly discredit observa- 

 tions of phenomena which are so rare that 

 our own chance for confirmation of them 

 may never come. We must, in such cases, 

 carefully scrutinize the testimony, exam- 

 ine the credibility of witnesses and their 

 chances of being mistaken. It is certainly 

 impossible at present to frame any ade- 

 quate hypothesis to account for this curious 

 and obscure electric appearance. The wit- 

 nesses agree that it is an accompaniment of 

 thunder-storms and that it resembles a ball 

 of fire floating in the air or moving along a 

 surface, such as the ground. It is not de- 

 scribed as very bright or dazzling, and the 

 size of the ball itself may be from an inch 

 or two to a foot or more in diameter. 

 Observers agree that it can persist for some 

 time and that its slow movement allows it 

 to be readily kept under observation while 

 it lasts. When it disappears there is usu- 

 ally an explosion and a single explosive 

 report like that of gun fire. Sometimes it 

 is said to disappear silently. Usually the 

 damage done by its explosion is only slight. 

 This summary of characteristics is common 

 to all accounts. Some accounts are even 

 more detailed, mentioning that the fiery 

 ball seemed to be agitated or with its sur- 

 face in active motion. I have found two 

 instances occurring many years apart and 

 in widely different localities in which it is 

 described as having a reddish nucleus, in 

 diameter some considerable fraction of the 

 whole. The outer fiery mass has been de- 

 scribed as yellowish in color. In some 

 instances it has been seen to fall out of a 

 cloud. It is described as entering build- 

 ings and moving about therein. Person- 

 ally I was for a long period in doubt as to 

 the reality of this strange appearance, 

 deeming it the result of some illusion, or a 



fanciful myth. But on hearing descrip- 

 tions by eye witnesses known to me as per- 

 sons not given to romancing, and finding 

 their accounts to correspond closely with 

 the best detailed descriptions in publica- 

 tions, my doubts have disappeared. 



In one instance, while observing the 

 lightning, during a heavy thunderstorm, a 

 companion, whose eyes were turned in a 

 direction nearly opposite to my own, sud- 

 denly called to me that a ball had just 

 dropped out of the cloud some distance 

 away. The view of the ground was ob- 

 structed by buildings and I unfortunately 

 just missed it. The noise of its explosion 

 was, however, heard in the direction indi- 

 cated by my fellow observer, as a single re- 

 port like the firing of a gun. At the time 

 I closely questioned him as to details of the 

 appearance. Our ignorance of its possible 

 nature is complete. No rational hypothe- 

 sis exists to explain it. Science has in 

 the past unraveled many obscure phe- 

 nomena. The difficulty here is that it is too 

 accidental and rare for consistent study, 

 and we have not as yet any laboratory 

 phenomena which resemble it closely. 



Sometimes photographs taken during 

 thunder-storms have been found to carry 

 curiously contorted streaks in some de- 

 gree resembling lightning flashes. Gener- 

 ally they have been found on plates upon 

 which undoubted lightning discharges have 

 been recorded. In some instances which 

 have come to my notice the streaks have 

 had the appearance of a string of dots or 

 beads and have been taken to represent a 

 very rare form of lightning known as bead 

 lightning. A number of such photographs 

 have been submitted to me for opinion as 

 to the nature of the curious streaks. In all 

 cases they are explained as due to the 

 camera having been moved without cap- 

 ping the lens, permitting images of lights, 

 such as arc lights, or spots of reflected 



