Something to Prove
Jennings set out to prove that the wind was the cause of the ribbon effect in a laboratory of the University of Pennsylvania, under the direction of Professor Arthur Goodspeed. To test Jennings' theory, the two scientists blew a blast of air across the direction of a single spark from an induction coil, resulting in the image shown here:
Report Plate 6. (149K)
In a letter to Franklin Institute Secretary Hoadley, Jennings claimed that the "Ribbon Effect" was his own original observation.
You can view the original letter penned in Jennings' elaborate scrawl by clicking on the thumbnail at right. Find a transcription of the letter below*.
Jennings also proved that a lightning flash does not confine itself to one plane. In order to demonstrate this fact, he placed two similar cameras one-hundred feet apart, and succeeded in obtaining two negatives of the same discharge. The plate at right shows the results of his experiment, which were displayed publicly for the first time at a convening of the members of The Franklin Institute in May of 1892.
*Transcription of Jennings to Hoadley, 10/3/1929:
My Dear Doctor: