NO. 12 REMARKARLE LIGHTNING PHOTOGRAPHS ABBOT 3 



occupying the same relative positions on the different rushes; in that respect 

 they beliave somewhat hke the striae in a vacuum. 



It is possible that these beads in reahty were not as wide as they appear, the 

 apparent width being caused by their intense light causing halation to a cer- 

 tain extent. The whole flash seems to be made up of these alternate light 

 and dark spaces ; in some places of the picture, where the flash was moving 

 either away from or toward the observer, it shows the beads very close together, 

 forming almost unbroken lines, but judging from the general appearance, it 

 seems that the divisions are of about uniform dimensions. When this pic- 

 ture was taken there was a continual display of meandering flashes, lasting for 

 over an hour. No rain was falling, and Mr. Spickerman judged the lightning to 

 be about + mile above the ground. The flash is certainly very interesting, and 

 I think that it deserves to be reproduced in the yearly report of the Institution, 

 if possible, together with the photograph taken by me on May 29, marked no. 4 

 in my last report. 



The barometer reading at 7 p.m. = 758.5 mm. Temperature = 29° C. Relative 

 humidity 80 percent. Wind, west. 



B. F. J. Schonland, of the University of Cape Town, Union of 

 South Africa, has lately been making somew^hat similar experiments 

 in lightning photography, on which he reported at the meeting of 

 the National Academy of Sciences at Washington, in April, 1934. 

 Mr. Schonland, calling at the Smithsonian Institution, examined Mr. 

 Larsen's photographs and expressed a particular interest in the one 

 here shown as plate i, figure i. At his suggestion this publication is 

 made, and it seemed to the writer interesting to include also figure 2. 



