Waterfall oaths.

I'm looking at the EIEC article 'Oath' (pp. 408-9), signed by Polome,
with the usual Adams-Mallory after-signature.

--start quote--
Hartmut Scharfe has suggested a common semantic core whereby one
swore, not by underground rivers but by the 'water-of-lightening',
i.e. the downpour (c.f. the waterfall imagery) of a thunderstorm, the
lightening guaranteeing the force of the oath.
--end quote--

We all know about Zeus sending a thunderbolt (i.e., a lightening
strike against those who needed to get whupped) and approximately,
killing those who received it.

Let us marvel at the fire and water of a thunderstorm: the lightening
igniting fires (and maybe doing apam napat), as the clouds send down
vast quantities of water. Adding air and earth to fire and water is
very easy. It's Lord Lightening zapping Lady Earth, while sending a
frisson thru Lady/Lord Underworld's behind.

I'm thinking about the current thread re *PerkWnos', the Thundergod.

The idea is that you swore an oath "at the waterfall", or some such
watery place, with the actually current English sense of 'may I be
struck down by lightning if ...'.

Yes, the lightening. Which is positively frightening.