How they kept the ice frozen at the ice rink in 1844 is fascinating:
The rink was based on a concrete surface, with layers of earth, cow hair and timber planks. Atop these were laid oval copper pipes carrying a solution of glycerine with ether, nitrogen peroxide and water. The pipes were covered by water and the solution was pumped through, freezing the water into ice. Gamgee had discovered the process while attempting to develop a method to freeze meat for import from Australia and New Zealand, and had patented it as early as 1870.
Photo by allyaubry.