Post it to www.instructables.com when you are done (and if you don't fry
yourself first). There are lots of 'Steam-Punk' projects there.
The Jacobs ladder is typically made with an ignition transformer from an oil
burning heating system. The secondary on these transformers is center tapped
with the tap going to case/earth. The output current is limited by the
internal core gap (iirc).
Might be a lot safer since the meter will not measure KV directly, that you
use a suitable scaling resistor and simply measure the mains (primary) side
of the transformer. For added effect, put a filament lamp of 100W or so in
series with the primary. Brightness is proportional to the current drawn and
gives a further current limit control. This may not give enough power for
the arc to travel up the column though.

Be safe!

"glutinous" wrote in message
...
I have just bought a vintage (1943?) DC 25-kilovolt meter (for a
Steam-Punk style 10kv Jacob's Ladder project).