This is a 1/6 scale model of a Hall's rotary steam engine from 1868. It could be described as the 19th century equivalent of the modern Wankel petrol engine in that it produces direct rotary motion with no intervening reciprocating motion.
The full size engine was not a commercial success, mainly because of its high steam consumption for the power produced.
The model here is being run on compressed air.
It was made using a set of casting and drawings from Reeves (https://www.ajreeves.com)
