Cap ID Q's, SG Q's

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Jonathan Peakall by way of Terry Fritz <twftesla-at-uswest-dot-net>" <jpeakall-at-mcn-dot-org>

I picked up some caps at a surplus store the other day, and I'm
wondering if anybody can tell me about them. They are marked:

N4700
701M
(the M is in a circle, like a trademark symbol) M40kv
507A

They test out to .007uf, and are seemingly ceramic. I am using three of
them on a small coil, using  half of a 10kv, 28 ma OBIT. Which brings me
to my next question. I have used a dual gap adjustable bolt and acorn
style SG and a three gap fixed gap with this setup. Overall, I seem to
get better performance out of the fixed SG. Using either, however, I get
periodic "flame outs" for a fraction of a second, then back to regular
firing. Varying the caps from .0014 to .0038 uf doesnt change this, nor
does trying different power levels with the variac and tuning. What
causes this? Somewhere on the list I saw a formula for calculating the
total gap for fixed multiple gap SG, but I searched and couldn't find
it. Anybody have that handy?

Thanks all

Jonathan