Battery: Mono Monday

Today's challenge was difficult to find, but by following the clever folk who had found what it was all about, I was able to discern that today's challenge is: 'an invention of the 18th century.'

I have chosen Alessandro Volta, Italian physicist, who invented the battery in 1799.

The photo is of several of my small, and most used, batteries illuminated by a hand-torch which uses two of these batteries.

The photo, as always, is improved by looking at it in large.

I believe that Laurie54 has set today's challenge. Thank you!