In A Nutshell Antiques and Interiors has dated this piece to the Victorian era.
On each side of the box are terminals where the metal probes are connected and it has its original paper label below the lid.

It is an excellent quality example made by S.Maw Son & Thompson and the winding handle and the wheel are ornately made from gilt brass in the form of dolphins.
I have not attempted to test the machine as far as whether it generates a shock and it is being sold as seen. However I can confirm that all the parts move as they should and when a voltmeter is used on the terminals it does produce a current.

It is in good condition for its age. It has been cleaned and lightly polished and the box has been given a light wax to retain its aged patina. The box has picked up some scuffs and knocks and minor marks over the years but no major damages. The drive band connecting the wheel to the coils is strong and turns well. The wires on the probes are slightly frayed in places there is no key to the box but overall it displays well.
The best description comes from the photos so please look at them all carefully and if you have any questions just ask.
Tracked UK Delivery £10
In A Nutshell Antiques and Interiors has dated this piece to the Victorian era.
Selling good quality victorian, georgian and earlier furniture, accessories & decorative items. Ashburton, devon. LAPADA member
You can view the stock and full dealer information on the In A Nutshell Antiques and Interiors Profile Page
In A Nutshell Antiques and Interiors is a registered member of LAPADA CINOA