stepped leaders

Hi All

I must say that this has been one of the most interesting discussions I
have ever had the pleasure to be a part of. It has not really offered a
satisfying answer to the initial question...How does the spark grow.

I would like to ask for some suggestions as to how to test several of
the proposed hypotheses. I for one would be happy within my abilities
and means to run some tests which would elucidate an answer. 

I already have, as I am sure others have, taken pictures pictures of the
zigzag phenom at one to 15 second exposure times  which has been
discussed. I will be attempting to take pictures at 1/1000 second with
some very fast film to see if anything jumps out.

If YOU have a suggestion to better define whats going on, please put it
on the list and let's see if we can settle this.