I’ll be waiting in the lifeboat.

Dear Word Detective: Is this (link attached) the origin of “tell-tale”? — Harry Farkas.

Oh boy, a test of my powers of verbal description. The link you sent is to a photo of a gizmo standard on the bridge of every large engine-powered ship until around 1950 and frequently seen in movies set at sea. It consists of a round dial on a drum-like contraption mounted on a short (waist height) pillar on the deck of the bridge. By moving a handle attached to a pointer on the dial, the pilot of the ship signals the gang in engine room to speed up, reverse, etc., the engines. Bells ring when this is done, and someone else usually says, “All ahead full, aye sir” or something similar. A bit later the same person screams “It’s an iceberg!” or maybe just “Godzilla!” I’m not sure what the proper term for that guy is, but I know I don’t want his job.

The picture you sent shows just such an instrument, with a smaller dial mounted below the large one with the handle, and the caption of the photo explains that it is the “tell-tale” from the USS Olympia, a battleship active in the Spanish-American War and now in danger of rusting into oblivion. But the caption is misleading. The big dial on top is an “engine order telegraph,” so-called because it relays orders to the crew in the ship’s engine room. It’s the smaller dial mounted below that’s called a “tell-tale,” and thereby, ahem, floats a tale.

“Tell-tale” is both a noun and an adjective, and both forms date back to the 16th century. The initial meaning of “tell-tale” as a noun was simply a person who “tells tales,” particularly stories maliciously disclosing the personal secrets of other people. A “tattletale,” in other words (“tattle” coming from Germanic roots meaning “to chatter or babble”). As an adjective in a figurative sense, “tell-tale” is probably best known from the title of the 1843 Edgar Allan Poe short story “The Tell-Tale Heart,” in which a murderer goes mad (or madder than he already was), believing that he (and the police who have arrived to investigate) can hear the heart of his victim still beating loudly beneath the floorboards where he has concealed the dismembered body.

“Tell-tale” as a noun in a figurative sense (i.e., not a person) appeared in the 18th century meaning, as the Oxford English Dictionary puts it, “A thing that reveals or discloses something not intended to be made known” (or, intriguingly, “A small hidden object placed so as to reveal a secret intrusion by its disturbance”). By the early 19th century, we were using “tell-tale” in the considerably less dramatic sense of “A device for mechanically indicating or recording some fact or condition not otherwise apparent; an indicator, a gauge.”

This is the sense which gave us “tell-tale” for the dial often mounted adjacent to the engine order telegraph on a ship’s bridge. Such “tell-tales” usually indicated the orientation of the ship’s rudder, but could also be a compass. Such a “tell-tale compass” was often mounted on the ceiling of the captain’s cabin facing downward so that he could check that the ship was on its proper course when he was away from the bridge.

“Tell-tale” was (and is) also used in non-maritime endeavors mean a mechanism or device designed to monitor performance and warn of malfunction or specific conditions. A “tell-tale pipe,” for instance, is a small pipe tapped into a cistern near the top. If water flows from the pipe, it means that the cistern is nearly full. A turnstile that counts people passing through it, the meter in a taxicab, and even the lights on a car’s dashboard indicating that the turn signal is blinking have all been known as “tell-tales.” Today most mechanical “tell-tales” have been replaced by electronic gadgets, and overall use of “tell-tale” as a noun, even in the personal sense, has faded, which is actually a bit odd in this age of the whistleblower and Wikileaks.

Incidentally, if you Google “Titanic” and “Louise Patten” (a British novelist), you’ll find an interesting new theory (too long to relate here) about why that ship actually sank back in 1912. Something tells me that the Titanic is going to be “telling tales” long after we’re all living on Mars.

I think I’ll just stay home and betray myself, thanks.

Dear Word Detective:  Contemporary use of the term “double-cross” is unambiguous. I have tried to research its origins, and posted queries on other sites, with no success. “Cross” in all permutations seems not to yield an answer. Please can you tell me where we got the phrase? — Maura Emm.

Unambiguous? That’s what they want you to think. Seems pretty ambiguous to me. Not that there’s anything wrong with ambiguity, of course. Still, sometimes a little certainty would be nice. A few years ago somebody gave me a book called “You Are Being Lied To.” I started to read it, but then I began to suspect that the title might be a meta-joke and the book itself be stuffed with lies. So I parked it on the shelf and left it there, where it still sits, making me strangely queasy. Any reasonable offer will be entertained, including driving a stake through the thing.

But seriously, there does seem to be a bit of unclarity in how “double-cross,” a staple of detective fiction, “heist” movies, and “secret agent” shows on TV, is actually used in everyday speech.

The root of “double-cross” is, of course, the word “cross,” which first appeared in Old English, borrowed from the Irish “cross,” which was derived from the Latin “crux” (which also gave us “crucial,” “crusade,” “excruciate” and, of course, “crux” meaning “central or critical point”). The appearance of “cross” in Old English (replacing the existing word “rood”) was closely tied to the spread of Christianity in Europe, so it’s not surprising that its initial sense in Old English was “the instrument of crucifixion on which Jesus Christ was put to death.” Over the next few centuries, “cross” acquired a wide variety of other meanings as a verb, adjective, adverb and noun, including the “x” made in lieu of a signature by someone unable to read or write. Almost all uses of “cross” involve that “two lines crossing” meaning in some fashion, whether literally or figuratively. When we say that someone is “cross,” for instance, we mean that the person is irritably opposing or quarreling with other people, a usage which seems to be rooted in currents or winds running across (perpendicular to) a sailing ship’s course and thus impeding its progress.

One of the meanings “cross” developed as a verb, in the early 19th century, was “to cheat, to act dishonestly towards or to betray” (“It wouldn’t have happened if we hadn’t been crossed. A journalist thought he could put one over on us,” Graham Greene, 1938). This colloquial use was popularized in the lower reaches of society at that time, and often employed to describe a criminal deal “gone bad” by the betrayal of one partner by the other.

A more ornate (and dangerous) species of betrayal in this world was the “double-cross,” first appearing in print in 1834, in which the malefactor pretends to be in cahoots with not one but two other parties, each of whom is trying to cheat the other. This “man in the middle” pretends to take the side of each party in the scam until the final moment, when both crooks come up empty and the “double-crosser” walks (or runs rapidly) away with the prize.

The “double” in this “double-cross” scenario refers, of course, to the fact that such a scheme is a double betrayal, as opposed to the simple “cross” of one crook cheating another. But perhaps because this sort of scenario is hard to carry out and thus fairly rare, “double-cross” almost immediately took on the far looser meaning in common usage of simply a “cross,” i.e., “betrayal by a trusted friend.” It is sometimes said that “double-cross” in this looser sense was originally justified if the deal itself was illegal or dishonest, making the betrayal of one thief by another a case of “crossing a crosser.” If that theory were true, the term “cross” would still be used to mean a simple everyday betrayal, but such use is very rare today. Even failure to speak up for a colleague in an office meeting is likely to be labeled a “double-cross.” So I’m afraid the original complex beauty of a “double-cross” has simply fallen victim to rhetorical inflation in the Age of the Drama Queen.