The Lancaster Watch Camera and its little sister, the ladies version, offer some of the earliest proof that spys are, indeed, among us. Ok, maybe not that, but they are a pretty neat piece of 1890′s camera engineering.

The watch pictured at the top is the ladies version, a rarer and smaller type that sold for $36,000 at the Bonhams auction in 2007. Only four of those are known to exist, but not because they were particularly difficult to make — because they were nearly impossible to use.

According to Bonhams’ camera expert Lionel Hughes:

It would have been very inconvenient to use as four very small catches had to be released in order to remove the glass screen and to fit a separate metal sensitised material holder for each exposure.

Constructed of engine-turned metal with nickel plating, the watch/camera expanded on its own when you opened it up. And if you could get them to work, the ladies version took 1 1/4in x 1in exposures, with the larger guy’s spy cam capturing 2in x 1 1/2in snaps.

(via Retronaut)