500,000 Volt Abacus is a very large and impractical method of counting.
It's simply a set of balls that can be moved along the high-tension cables connecting two high voltage pylons. Of course there are some extra wires to make up the array, and the cables are arranged differently to resemble an abacus.
Actual counting on the abacus is a tricky business that can only be achieved by moving the balls along the wires using a highly insulated pole, and while being totally isolated from any risk of becoming a 500,000 volt earth connection.-- xenzag, Sep 17 2014 An easier way to reach your balls... Gondola_20with_20the_20Wind [normzone, Sep 17 2014] Do not use in rainy weather ...-- 8th of 7, Sep 17 2014 + i can imagine a learner's version charged by an 0.5MV Van de Graaff machine.
It would be cool to have some of the vertical wires be made of highly insulating material (e.g. teflon.) With the right sort of beads, it might count by itself!-- csea, Sep 17 2014 Why was this idea not brought to my attention sooner?-- MaxwellBuchanan, Sep 23 2014 You were busy. We didn't like to disturb you. As you pointed out, it's not very often that three daughters of your estate staff all have their fourteenth birthday on the same day. Even with the ginseng and the injections of monkey-gland extracts, you need to take things a bit easier.-- 8th of 7, Sep 23 2014 Ah! So they were _my_ daughters! I thought the noses looked familiar. Explains why the memsahib was making such a fuss over them.-- MaxwellBuchanan, Sep 23 2014 random, halfbakery