To Blair and Murray we may add Noah Webster,. According to Baron 1982, Webster in his 1794 grammar strongly disapporved the terminal preposition. So the 19th century began with three widely used, standard school texts formidably opposing the preposition at the end of the sentence. The topic entered the general consciousness through schoolteachers, and, as we have seen, it persists there still.
Perhaps the construction was relatively new in Dryden's time, and he was reacting, as many do, to something new and obtrusive. Bu he did pick one out of Ben Jonson, and Shakespeare had used it too:
Thou hast no speculation in those eyes
Which thou doest glare with (Macbeth)
We also have evidence that the postponed preposition was, in fact, a regular feature in some constructions in Old English. No feature of the language can be more firmly rooted than if it survived from Old English. Evidently the whole notion of its being wrong is Dryden's invention.
And what is curious is the fact that the first example Dryden picked to make his point about (the one quoted above) contains a construction in which the preposition must be put at the end - a relative claused introduced by that. Some recent commentators such as Burchfield 1981, 1996 have pointed out that there are a few constructions in which the postponed preposition is either mandatory or prefereable. The restrictive clause introduced by that has required the postponing of the preposition since Old Enlgish. Here are some examples:
"Now," thought he, "I see the dangers that Mistrust and Timorous were driven back by." - John Bunayn, Pilgrim's Progress, 1678
Fanny could with difficulty give the smile that was here asked for - jane Austen, Mansfield Park, 1814
... owing to the restrictions of space that Mr. Belloc has contented himself with - Times Literary Supp., 20 Feb. 1937
... with whatever it is that good English is good for - James Sledd, in Greenbaum 1985
When the restrictive clause is a contact caluse (with the relative pronun omitted), the preposition also must come at the end:
There were some of the placid blessing I promised myself the enjoyment of - Samuel Johnson, The Idler, 10 June 1958
The Universtiy is one most people have heard of - Robert Frost, letter, 20 Jan. 1936
... to visit a guy I went to Ohio State with - James Thurber, letter, 1937
... something all of us can learn a thing or two form - Simon 1980
Clauses introducted by whatrequire postponing the preposition:
I know what you are thking of - Jane Austen, Mansfield Park, 1814
.. what the same cars look like- Young America Junior Reader, 7 Mr. 1952
That's what the taxpayers provide our salaries and buildings for - John Summerskill, quoted in Change, October 1971
Wh- clauses in general tend to have the preposition at the end:
... the reception which this proposal met with - Henry Fielding, Jonathan Wild, 1743
... aspect of Army life which I delight in - Edward Weeks, Atlantic, December 1952
... people ... whom you would like to dine with - Archibald MacLeish, letter, 13 Sept. 1954
... a pitch which the New York batter... swung at - E. L. Doctorow, Ragtime, 975
Wh- questions usually have the preposition postponed:
... What else are they for? - Trimble 1975
"And what are they made of?" Alice asked - Lewis Carroll, Alice's Adventures in Wonderland, 1865
Whom is that literature about? - Earl Shorris, N.Y. Times Book Rev., 1 July 1984
Infinitive clauses have the preposition at the end:
He had enough money to settle down on - James Joyce, Dubliners, 1914
... should have had a paragraph all to himself to die in - Leacock 1943
The pecualiarities of legal English are often used as a stick to beat the official with - Gowers 1948
Burchfield also mentions two other constructions. One is the passive:
None of them ... has yet been heard of - The Intimate Notebooks of George Jean Nathan, 1932
The other is the exlamation: "What a shocking state you are in!" (example from Burchfield). And here are a few assorted inversions, passives, and other constructions in which the terminal preposition is idiomatic:
Albania, indeed, have seen more of than any Englishman -Lord Byron, letter, 3 May 1910
... the Pretender had not gratified his enemies by getting himself put an end to - Henry Adams, letter, 3 Sept. 1863
They probably know which shelf everything is on in the refrigerator - And More by Andy Rooney, 1982
... shorts, size 36, which she spent the rest of the evening crawling in and out of - Russell Baker, N.Y. Times Mag, 29 Jan. 1984
The preposition at then has always been an idioamtic feature of English. It would be pointelss to wrory about the few who believe it is a mistake.
Idle hands, you know.