WHEN WE are very young, we tend to regard the ability to use a colon much as a budding pianist regards the ability to play with crossed hands: many of us, when we are older, regard it as a proof of literary skill, maturity, even of sophistication: and many, whether young, not so young, or old, employ it gauchely, haphazardly or, at best, inconsistently.
Etymologically, colon (Greek kōlon) was originally a person's or an animal's limb; hence, portion of a strophe in choral dancing, hence a division in prosody; hence, also, a clause-notably a principal clause-in a sentence; hence, finally, the sign [:] marking the breathing-space at the end of such a clause.
Historically, the colon not unnaturally preceded the semicolon. In English the colon long predominated over the semicolon, but throughout the 19th Century and indeed until the middle 1920's, except in such writers as the Landors, it fell into disuse for structural purposes and seldom occurred for any purpose other than the annunciatory. Since 1926, when H.W. Fowler's admirable book, A Dictionary of Modern English Usage, appeared, the colon has been returning to favour and a much more various employment; twenty years earlier the Fowler brothers (H.W. and F.G.) had, in The King's English, sown the seed of this fruitful counter-revolution. To be mulcted of our money and mutilated of our property is serious enough: to be deprived of our colon would be intolerable. Several writers, whom it were invidious to name, have perhaps been somewiiat too revolutionary; nevertheless, they are performing a service more than yeoman, for they have re-introduced the colon to a public indifferent to its value and almost ignorant of the name, some good souls associating colon with nothing more literary than the large intestine.
The main purposes and chief uses of the colon may be summarized thus: