series neon xformer dc power supply?

Hello all,
I recently came across a website with a schematic for a dc power supply
using two 15 Kv neons in series feeding a full wave high voltage dc
rectifier (both diode and tube rectifiers are presented).  The author notes
that after rectification, the supply is capable of around 42 Kv output (30
Kv before).  Now I've read a lot of material suggesting that neons cannot
be used in series, only parallel, and I'm wondering if such a supply would
work without harming the neons?
John Bowers