Laudator Temporis Acti

M.L. West, Hesiod: Works & Days. Edited with Prolegomena and Commentary (Oxford: Clarendon Press, 1978), pp. vi-vii:

Another novelty is my sporadic use in Latin quotations of the apex (') to mark long vowels. It seems to me most regrettable that the very existence of this useful and decorative sign, which the Romans themselves saw fit to employ, is almost universally concealed from those studying Latin at school and university, and that practically no attention is paid to teaching the correct quantities of vowels in Latin words except in so far as this is necessary for the scansion of verse. I cordially invite all those sufficiently informed in the matter to follow my example. It is an honourable cause, and they need not feel they are doing something eccentric like going out into the street in gipsy earrings. Rather it is like restoring fluoride to water supplies that are deficient in it; it will certainly afford some protection against the decay of knowledge.

Few, it seems, have accepted West's cordial invitation to follow his example. Perhaps there aren't that many sufficiently informed in the matter.

On the apex, see a work by the scholar with the palindromic name, Revilo P. Oliver, "Apex and Sicilicus," American Journal of Philology 87 (1966) 129-170, who wrote (at 131):

The apex is found in thousands of inscriptions, and also in the few surviving papyri and wax tablets, of the last six decades of the Republic and the first two centuries of the Principate, after which it becomes increasing rare. The innumerable occurrences of it make it obvious that its function was to distinguish long vowels.

For some amusing remarks on false quantities, see Hugh E.P. Platt, A Last Ramble in the Classics (Oxford: Blackwell, 1906), pp. 152-158 (available through Google Book Search and the Internet Archive), e.g. (at 153):

Lawyers have some venerable stories, as of the counsel who talked of nolle prosēqui, and was reminded by the judge that at the end of term it was a pity to lengthen anything unnecessarily. In the House of Commons the last false quantity made by a distinguished man was when Mr. J. S. Mill misquoted Horace, Ep. i. 16. 47, as 'Habes pretium, cruci non figeris'; and Mr. Lowe in his reply brought in 'non pasces in cruce corvos,' 'which I prefer,' he said, 'to cruci non figeris.'

In the House of Lords, as Mr. Herbert Paul relates in his paper on the Decay of Classical Quotation (Nineteenth Century for April, 1896), Lord Clarendon achieved a 'record' by committing two false quantities in consecutive words, when he quoted Martial [1.16.1] in this fashion:

Sunt bona, sunt quaedam mediocria, sunt plura mala.