mercurial

noun

1. (obsolete)Any of the plants known as mercury, especially the annual mercury or French mercury (Mercurialis annua).
2. A person born under the influence of the planet Mercury; hence, a person having an eloquent, quickwitted, furtive, or volatile character.

   “As for [Lambert] Simnell, there was not much in him, more then that hee was a handſome Boy, and did not ſhame his Robes. But this Youth (of whom wee are now to ſpeake) was ſuch a Mercuriall, as the like hath ſeldome beene knowne; and could make his owne part, if at any time hee chanced to bee out.”

3. A chemical compound containing mercury.
4. (historical)A preparation of mercury, especially as a treatment for syphilis.

   “She had paſſed through the milder Remedies frequently without ſucceſs: upon which account I deſigned Mercurialls; and beginning with Venæſection, afterwards purged her with decoct. epithymi, as it is preſcribed in the method of Cure. [...] After I had thus evacuated the Plethora, and diſpoſed her body for Mercurialls more operative, I gave her each morning and evening a few grains of Mercur. diaphoret. in a bolus with conſ. lujule and Mithridate, [...]”

   “[A] small dose of the mercurial may cause excessive salivation; and, if this discharge be attended by much soreness of throat, it is most difficult to determine whether the salivation is actually the result of the mercurial, or merely symptomatic of the sore throat and cold. If it proceed from the mercurial, there will generally be some tenderness of the gums, a soft and flabby state of the sides of the tongue, and it will generally be more obstinate.”

adj

1. (comparable)Having a lively or volatile character; animated, changeable, quick-witted.

   “his mercurial temperament”

   “[Y]our Mercuriall wit hath mangonized a Gigantean fury with an humble hue.”

   “When the ſoule bringeth its fire deſire out of its owne ſelfe-will into the Love-deſire of God; and goeth out of its owne ſelfneſſe, and ſinketh into the mercy and compaſſion of God, and caſteth it ſelfe into the death of Chriſt; and willeth no longer the fire-ſource, but deſireth in its fire-life to be dead in the death of Chriſt; then the poyſon of the Mercuriall life dyeth in the will of iniquity, and there ariſeth a new twigge, and budding of love-deſire.”

   “From the natural Mercurial Briskneſs of her [Sally Salisbury's] Temper, a ſedentary Life had ever been her Averſion, wherefore ſhe rather choſe to follow the Fortunes of a Wheel-Barrow, than thoſe of a Diſtaff; [...]”

   “Robert Maxwell, who has died aged 68, was one of the most mercurial postwar operators not only in the British media but British commerce generally, a self-made individualist who managed - just - to keep a fitful peace with the mores of a British corporate scene notoriously unaccepting of flamboyant personalities.”

2. (not-comparable)Pertaining to the astrological influence of the planet Mercury; having the characteristics of a person under such influence (see adjective sense 1).

   “The Sun to the Terms of Mercury. It inclineth the native to be Mercurial, given to ſtudy Arts and Sciences, and to delight in reading, and to follow his Calling with chearfulneſs.”

   “6thly, The ☽ separates from a △ of ♂︎, and applies to ☍ of ☿, lord of the 3d; which intimated that some neighbour of the querent, either with a letter, words, or cross information, would wholly destroy the querent's hopes; and that mercurial men, viz. scholars or divines, would be his enemies: [...]”

3. (not-comparable)Pertaining to the planet Mercury.
4. (not-comparable)Of or pertaining to the element mercury or quicksilver; containing mercury.

   “Beware alſo of Mercuriall lotions, I meane any which haue Mercurie Sublimate Precipitat or otherwiſe prepared in them, for though they haue good qualities, yet they are vpon my knowledge and experience dangerous, [...]”

   “[...] Dr. Francis Fuller, [...] upon wearing a Quick-ſilver Girdle, for the Cure of the Itch, (and that after an inconſiderate and raſh manner) was brought under a violent Spaſmodick Diſtemper, which was ſupposed by himſelf and others to be owing to ſome Mercurial Particles lodg'd in ſome excretory Ducts of the Brain.”

   “If to theſe we add the inconveniences inſeparable from mercurial preparations, and which are always the conſequences of their uſe; if we conſider the ſmall number of patients to whom mercury may be exhibited with ſafety, [...] the uſe of mercurial medicines will be confined within very narrow limits.”

   “[I]n the month of May, a mercurial thermometer, having its bulb covered with paper, and blackened in a similar manner to the spirit one, was inclosed in a square bottle of thin glass, four inches wide, to protect it from the wind.”

5. (not-comparable)Caused by the action of mercury or a mercury compound.

   “I ſaw in the Year 1709. a notable inſtance, where a Phyſician order'd the Patient to be Bled five times in a Mercurial Salivation in a Caſe not Venereal; when he did ſpit at the rate of ℔ iv. per diem, and it was at the height, and yet notwithſtanding it did continue for all this, and the Patient eſcap'd with his Life.”

   “The last exciting cause of the mercurial ulcer, which I shall now mention, is the use of the knife or of the caustic, during a mercurial course, to wounds made or enlarged at this time; for the great additional irritation, which the operation must produce, disposes such wounds to take on easily the mercurial disease.”

6. (Roman, not-comparable)Pertaining to Mercury, the Roman god of, among other things, commerce, financial gain, communication, and thieves and trickery; hence (comparable), money-making; crafty.

   “Near-synonym: Hermesian”

   “I know the ſhape of's Legge: this is his Hand: / His Foote Mercuriall: his martiall Thigh / The brawnes of Hercules: but his Iouiall face— / Murther in heaven?”

   “[Benjamin] Franklin, the mechanic of his own fortune, [...] tendering, from the self-created nation, to the mightiest monarchs of Europe, the olive-branch of peace, the mercurial wand of commerce, and the amulet of protection and safety to the man of peace on the pathless ocean from the inexorable cruelty and merciless rapacity of war; [...]”

7. (alt-of)Alternative letter-case form of mercurial.

   “The alchemists too spoke of the return of the Mercurial spirit as a ‘celestial rain’, or ‘dew’ (Norton’s stilla roris madidi, Dee’s ros caeli), a ‘divine water’ falling from the ‘heaven’ of the vessel to reanimate the blackened earth of the Stuff.”

   “In addition, the magnetometer on MESSENGER will characterize Mercury’s magnetic field in detail from orbit over four Mercurial years.”

   “Then he is called a daemon in order to make it obvious that such gifts are handed down from Mercury himself via a Mercurial daemon to a rational Mercurial soul.”

   “However, despite these talents, despite the fact that he saw Mercurial as well as Jovial strains in his paternity, and despite his opinion that Mercury shared with Jupiter a special need of rehabilitation, Lewis claimed no special relationship with the planet of the second sphere. In fact, he confesses that the Mercurial essence is almost beyond his grasp: […]”