Pelton's Patent Hurdy-Gurdy water wheel. This undershot whell develops 4 horsepower.
The patent related to the divider which sends the water out sideways rather than straight back, and thus develops 30% more power. A simple device with a very powerful effect.
Gold panning demonstration. The pan is zinc-plated and has ridges all round the rim. First you wash out all the fine silt. Then, with the pan tipped away from you, slide the lighter pebbles out. When you are left with the heavy fine silt, swirl round with a "wave motion" and the tiny flecks (or very occasionally small nuggets) of gold become visible in the lowest part of the pan.
Memorial to the first deep introduced into Otago. They adapted far too well, and eventually because pests. Many of the wild deer have recently been captures, and they are now farmed for venison.