While most of us are limited to the visible spectrum, people with a condition called aphakia possess ultraviolet vision. Aphakia is the lack of a lens, due to surgical removal for cataracts or congenital defects.
A railroad lantern and a railroad lamp are two different things. Lanterns were designed to be portable (i.e. carried) and were basically globes surrounded by a metal frame with a fuel source. When you think of a railroad worker swinging a signal, think lantern.
External combustion engine. Model Stirling engine, with external heat from a spirit lamp (bottom right) applied to the outside of the glass displacer cylinder. Sectioned steam locomotive. Although the fire is within an enclosed firebox, this is still an external combustion engine, as the exhaust gas and the steam working fluid are kept separate.