The satiric fable had a considerable vogue throughout the century, and collections appeared at frequent intervals.[37] Nearly all have allegorical elements and contain little direct satire, their main object being to point out and ridicule the weaknesses and follies of human nature. The octosyllabic couplet, the favorite measure for fables, was also a popular verse form in familiar epistles and humorous tales, modelled on the work of Prior, Gay, and Swift.[38] Ephemeral political satire continued to flourish in rough and indecorous street-ballads, sometimes rising almost into literature in the productions of men like Charles Hanbury Williams (1708–1759) and Caleb Whitefoord (1734–1810). With the inception of the _Criticisms on the Rolliad_, political verse assumes a position of distinct importance in the history of satire. The material represented under the title _Criticisms on the Rolliad_ was published in the Whig _Morning Herald_, beginning June 28, 1784, shortly after the fall of the Fox-North coalition and the appointment of the younger Pitt to the office of Prime Minister. It presents extracts from a supposed epic, based on the deeds of the ancestors of John Rolle, M. P., who had become the pet aversion of the Whigs. The alleged verse excerpts, all of them short, are amalgamated by clever prose comment. The editors included a group of young and ambitious Whig statesmen: Dr. Lawrence, later Professor of Civil Law at Oxford, who furnished the prose sections; Joseph Richardson (1755–1803); Richard Tickell, already mentioned as the author of _The Wreath of Fashion_; and two former cabinet ministers, General Fitzpatrick, the friend of Fox, and Lord John Townshend. The object of these men was to belittle and deride the more prominent Tories in both Houses, particularly Rolle, Pitt, Dundas, and the Tory Bishops, by singling them out, one by one, for ridicule. Their verse was a flippant and free form of the heroic couplet. Although their main purpose was political, they dealt only slightly with party principles, preferring rather to excite laughter by their personal allusions. The marked public approbation which attended their experiment led the editors to continue their project in a series of _Probationary Odes for the Laureateship_, comprising parodies of twenty-two living poets. The odes follow the plan of the _Pipe of Tobacco_ (1734) of Isaac Hawkins Browne (1705–1760), which burlesques the poetry of Cibber, James Thomson, Swift, Young, and Ambrose Phillips.[39] The plan of the contributors was further amplified in _Political Eclogues_ and _Political Miscellanies_, which keep to the original policy of vituperation, at the same time showing a striking deterioration in the quality of the verse. The first zest had grown languid, and in the last collection, _Extracts from the Album at Streatham_ (1788), containing poems purporting to be by several ministers of state, the verse had no value as literature.