What Is the Heptaplasiesoptron?

Part 1 of my Guide to Dukes Prefer Blondes

Vauxhall Gardens, which existed 1661-1859, was a famous pleasure garden in Lambeth, on the south bank of the Thames.

While, sadly, I haven’t found any images of the Heptaplasiesoptron yet (still hoping), I have found several descriptions.

From The Gentleman’s Magazine, Vol 131 (1822):

Monday, June 3. 1822
...the principal novelty is of a more expensive kind; it is called in the bills " The Heptaplasiesoptron" and is formed at one extremity of the saloon...