Williams replies: Eyewitness accounts often provide valuable input to scientific progress. If greater attention had been paid to eyewitness reports of transient luminosity in the middle atmosphere, progress in sprites research would no doubt have been quicker. This expectation seems particularly true given greater awareness of C. T. R. Wilson’s early predictions on sprites (ref. 1 in my article).
Capps’s characterization of quick dismissal by the scientific community is perhaps unjust. Many scientists simply find little to say about qualitative observations. As Lord Kelvin said, “When you measure what you are speaking about, and express it in numbers, you know something about it; but when you cannot measure it, … your knowledge is of a meager and unsatisfactory kind.” Ball lightning is another area in atmospheric electricity in which relatively little progress has been made, largely because good quantitative measurements are scarce.
Given the limitations on article length, I chose to concentrate on aspects of sprites research for which numbers are available and where observations agree and disagree. The earlier historical background Capps mentioned was addressed in the review article by Craig Rodger (ref. 4 in my article). Further discussion of historical observations was given in an older paper that W. A. Lyons and I wrote for the American Meteorological society’s Conference on Atmospheric Electricity in 1993.
I look forward to further discussions with Capps about the eyewitness accounts he mentions, which may not be generally available to other scientists.
