144 



SCIENCE 



[N. S. Vol. XXXI. No. 787 



ward elastic reaction of the air becomes so 

 great that the meteorite rebounds, but if the 

 angle of the path is a high one, atmospheric 

 friction and impact retard the meteoric veloc- 

 ity to so great an extent that gravity gets the 

 victory, and the last part of the meteor's fall 

 is vertical. If this conclusion is correct, there 

 should be some evidence that bolides which 

 strike the ground fall more often than not in 

 a vertical direction. I am not aware that such 

 evidence has been sought, or especially noted. 

 The present instance is so well authenticated, 

 that it seems worth putting on record. Sub- 

 sequent investigation has proved that the 

 fall of the meteorite occurred at about quarter 

 before seven o'clock on the evening of Thurs- 

 day, October 7, as witnessed by several people 

 in Norwood. Frank W. Very 



Westwood, Mass., 

 October 12, 1909 



A LABORATORY ILLUSTRATION OF BALL LIGHTNING! 



In Dr. Elihu Thomson's address at the 

 opening of the Palmer Physical Laboratory 

 at Princeton University he made, with regard 

 to ball lightning, the statement, " The diffi- 

 culty 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."' This suggested to me that a phe- 

 nomenon which I witnessed some six or seven 

 years ago might be worth recording. 



With a copper wire a student accidentally 

 short-circuited the terminals of an ordinary 

 110-volt circuit. I happened at the time to 

 be a few meters from him and to be looking 

 toward the terminals. At the instant of the 

 short circuit I saw an incandescent ball which 

 appeared to roll rather slowly from the ter- 

 minals across the laboratory table and then 

 disappeared. As I remember it, I should say 

 that the ball may have appeared to be about 

 three centimeters in diameter. I think no one 

 else in the room saw anything more than a 

 flash of light — much as if a fuse had blown. 

 On the table where the ball had rolled we 

 found a line of scorched spots, as if the ball 

 had bounced along the table and had scorched 

 the wood wherever it touched. As I remem- 



» Science, XXX., p. 868, December 17, 1909. 



ber them, these scorched spots were rather 

 close together, perhaps not more than one or 

 two centimeters apart. In the top of the table 

 was a crack perhaps a millimeter or two wide, 

 and at this crack the scorched line ended. In 

 a drawer immediately under this crack we 

 found a tiny copper ball, perhaps a millimeter 

 in diameter. Apparently the ball that rolled 

 along the table was incandescent copper vapor, 

 although my memory of it is rather of a yel- 

 low-white than of a greenish light. 



The above suggested the possibility of a 

 laboratory study of a phenomenon which may 

 very possibly be similar to that of ball light- 

 ning, but I have never attempted to repeat 

 the experiment. A. T. Jones 



PuKDUE University 



.'' BALL LIGHTNING 



To THE Editor of Science: In the address 

 on " Atmospheric Electricity " by Professor 

 Elihu Thomson, on pages 867 to 868 in the 

 issue of December 17, reference is made to 

 lightning in the form of a ball of fire. This 

 calls to my mind an experience which I had 

 some fifteen years ago while watching a heavy 

 electrical storm. I observed what appeared to 

 be a ball of fire between two and three feet in 

 diameter rolling along the street. It was also 

 accompanied by several others of smaller size. 

 This appearance occurred just after a very 

 heavy electrical discharge to a telephone pole 

 some few squares away. The discharge along 

 the telephone wire heated the wire to red heat. 

 The wire broke on account of this heating and 

 a section of some considerable length was 

 hurled along the street with a whirling motion. 

 The rapidity of the rolling motion gave the 

 appearance of a ball, as it also gave a forward 

 motion to the ball of fire. Subsequent investi- 

 gation revealed the two ends of the wire dan- 

 gling from adjacent poles with a considerable 

 length of the wire missing. I beg to suggest 

 that the rapid heating of metal particles in 

 some manner similar to this may be the cause 

 of many of the so-called balls of lightning. 

 Louis M. Potts 



Baltimore, !Md., 

 January 10, 1910 



