This pic shows the two I got that day. The one next to the Bullers is a Thomas with a partial -20% - stamped mark on it.

The metal pins shown here are illustrated in a 1907 talk by the Engineer who set up this Power Scheme, when he addressed the 'The Electrical Association of New South Wales (Australia)'.

A later pic will show the exact insulator that the Hydro Electric Scheme used that is also in the booklet of the Engineers address.