Laudator Temporis Acti

The Examiner, No. 936 (Sunday, Jan. 15, 1826), p. 42:

Lord Belgrave, having clenched a speech in the House of Commons with a long Greek quotation, Sheridan, in reply, admitted the force of the quotation so far as it went, "but," said he, "had the Noble Lord proceeded a little further, and completed the passage, he would have seen that it applied the other way." Sheridan then spouted something, ore rotundo, which had all the ais, ois, ous, kon, and kois, that give the world assurance of a Greek quotation; upon which Lord Belgrave very promptly and handsomely complimented the Hon. Member on his readiness of recollection, and frankly admitted, that the continuation of the passage had the tendency ascribed to it by Mr Sheridan,and that he had overlooked it at the moment when he gave his quotation. On the breaking up of the House, Fox, who piqued himself on having some Greek, went up to Sheridan and asked him, "Sheridan, how came you to be so ready with that passage? It certainly is as you say, but I was not aware of it before you quoted it." It is unnecessary to observe, that there was no Greek at all in Sheridan's impromptu.

The source is given as Westminster Review. Apocryphal, perhaps, but amusing.