Something very odd - a periscope and Wollaston combination perhaps?

[Steven Tribe]

I still find it hard to resist something which is way beyond "normal" lens design conventions!

Anonymous maker, unmarked iris (which isn't a surprise). Two lenses of different focal lengths. two extension tubes.

I deduce the lenses are simple meniscus, like Plasticca, Objectif d'Artiste, Wollaston, Reinhold and periscopes.

It isn't vey big, in spite of appearance. E**y 380861444249.

[Amedeus]

Interesting find ... looking forward to hear about it when you get it into your hands

[Steven Tribe]

It is, indeed, a miniature version of the Objectif d'Artiste! Very well made set.

Looks like quite a few makers experimented with using Wollaston lenses, as single lenses and pairs during the period after 1890, when there was not the same demand for just reproducing what photographers could see with their own (well corrected) eyes.

Another way of looking at it is that this is an economical product which satisfied those who couldn't afford the brand name aplanats etc. Looking at catalogues pre-WW1, there were a range of no-name periscopes -at budget prices - before the listing of branded lenses.