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.
A steamboat uses a steam engine similar to those on a steam locomotive. An external wood or coal fire heats water in a boiler, and the pressure of its expansion into steam is â¦ used to turn a shaft that is connected to paddlewheels, or to a propeller blade.