Thought I would share the result of a bit of idle research.
I lost a bet re which Admiral said “damn the torpedoes, full steam ahead”—could not have been Farragut, I thought, as torpedoes had not yet been invented in the Civil war. I said Dewey, who famously actually did say, “Gridley, you may fire when ready”.
Turns out that the phrase (never actually uttered) was indeed attributed to Union Navy Admiral Farragut, because in the Civil War, a torpedo was what we would call a (naval) mine today. Only later in the 19th century, did torpedo come to mean a self propelled naval mine.
Torpedo itself comes from “any sluggish bottom-dwelling ray of the order Torpediniformes having a rounded body and electric organs on each side of the head capable of emitting strong electric discharges”. Torpedo from the Latin for “numb”.
Mine refers to the tunneling under enemy fortifications. Explosives would be put into the mine.
Question is: why/when did torpedo come to mean exclusively self propelled naval mine, and the word “mine” used to mean a relatively stationary explosive set off by contact or proximity.
Landmines (also called land torpedoes), explosives set off by pressure of personnel or vehicles, developed in the mid 19th century. Earlier mines were more like the modern “claymore mine”, intentionally set off by troops as part of a defensive network.
So “mine”, the word for tunneling in the earth now means ‘an explosive floating in water’, and ‘torpedo’ the word for a relatively stationary flat fish now means a something best described as a water rocket.