Toronto is a strange place. In restaurants and bars the smoking lamp is out. But in the cannabis buyers club you can smoke all you like.
The smoking lamp probably came into use during the 16th Century when seamen began smoking on board vessels. The lamp was used to light the smoke before matches were invented.
The smoking lamp was also a safety measure. It was devised mainly to keep the fire hazard away from highly combustible woodwork and gunpowder.
Most navies established regulations restricting smoking to certain areas on board. Usually, the lamp was located in the forecastle or the area directly surrounding the galley indicting that smoking was permitted in this area.
Even after the invention of matches in the 1830s, the lamp was an item of convenience to the smoker. When particularly hazardous operations or work required that smoking be curtailed, the unlighted lamp relayed the message.
The smoking lamp is lighted or the smoking lamp is out were expressions indicating that smoking was permitted or forbidden. The smoking lamp has survived only as a figure of speech. When the officer of the deck says the smoking lamp is out before drills, refueling or taking ammunition, that is the Navy's way of saying cease smoking.