to stay up very late in order to study or do some other work
The word oil was used in various phrases referring to the use of oil in a lamp for nocturnal study. For example, to lose one’s oil meant to study or labour in vain; the English historian Edward Hall (1497-1547) wrote the following in The vnion of the two noble and illustre famelies of Lancastre [and] Yorke, published in 1548:
Thei were like to lese bothe worke and oyle, cost and linyng.
And to smell of oil meant to bear marks of laborious study. The English physician and author Thomas Browne (1605-82) used this phrase in his address to the reader at the beginning of Pseudodoxia Epidemica: or, Enquiries into Very many Received Tenents, And commonly presumed Truths:
A work of this nature is not to be performed upon one legg; and should smel of oyl, if duly and deservedly handled.
The first known user of midnight oil was the English poet Francis Quarles (1592-1644) in Emblemes (1635):
Wee spend our mid-day sweat, our mid-night oyle;
Wee tyre the night in thought; the day, in toyle.
Other verbs besides to spend were subsequently used. For example, the English poet William Shenstone (1714-63) wrote in Elegy XI. He complains how soon the pleasing novelty of life is over:
Smit with the charms of Fame, whose lovely spoil,
The wreath, the garland, fire the poet’s pride,
I trimm’d my lamp, consum’d the midnight oil—
But soon the paths of health and fame divide!
The Latin noun lucubrum denoted a small light, a lantern. It was derived from lux/luc-, meaning light.
From lucubrum, the Latin verb lucubrare meant to work by lamplight, work at night, and to make, compose (a work) by lamplight, at night. And, from this verb, the Latin noun lucubratio(n-) meant a working by lamplight, nocturnal study, night work.
From these Latin words, English has two terms, now obsolete:
– the verb to lucubrate, which means to write or study, especially by night, and, by extension, to produce learned written material;
– the noun lucubration, which means writing or study, and, usually in the plural lucubrations, a learned or pedantic piece of writing.
And in French, élucubrer and élucubration are from the intensive Latin forms (with the prefix ex-, meaning thoroughly) of lucubrare and lucubratio(n-).
Originally, these French words also referred to laborious thought and study, but now the verb élucubrer means to dream up and élucubrations (in the plural) means wild imaginings.