The sniggeringly pseudonymous Roger Pheuquewell’s contribution to a series of 18th-century erotic novels imagining the female body as land needing to be “ploughed” is among a collection of books from the British Library’s “Private Case” – a collection of obscene titles kept locked away for more than a century that are finally being shared with a wider audience.

First published in the 1740s, the Merryland books were written by different authors, all describing the female anatomy metaphorically as land ripe for exploration. Thomas Stretzer, who died in 1738, was the then-anonymous author of A New Description of Merryland, credited in a 1741 edition to one Roger Pheuquewell. In it, the author describes his “instrument” as “of a large radius … inferior to none”, writing of how “to say truth, the nature of the Soyl is very strange, so that if a man do but take a piece of it in his hand, twill cause (as it were) an immediate Delirium, and make a man fall flat upon his face upon the ground, where if he have not a care, he may chance to lose a limb, swallowed up in a whirl-pit”.

Facebook Twitter Pinterest ‘The Soyl is very ftrange’ … a page from A New Description of Merryland by Roger Pheuquewell. Photograph: British Library

Together with an 18th-century directory of sex workers in the Covent Garden area of London, and the violent erotic works of the Marquis de Sade, the Merryland books are among the 2,500 volumes in the British Library’s Private Case collection. The volumes have now been digitised, and are being made available online by the publisher Gale as part of its Archives of Sexuality and Gender academic research resource.

“There was essentially a series of cupboards in the keeper’s room from the 1850s, where material that was deemed to be unsuitable was kept locked away – usually because of its obscene nature, so pretty much anything to do with sex,” said Maddy Smith, curator of printed collections. “It was added to throughout the 19th century, and this carried on until around 1960, when attitudes to sexuality were changing.”

The collection dates back to 1658, with the book Rare Verities: the Cabinet of Venus Unlocked and Her Secrets Laid Open – the double entendre very much intended, according to Smith. It also features 40 copies of John Cleland’s 18th-century novel Fanny Hill or Memoirs of a Woman of Pleasure, which is considered to be the first pornographic novel written in the English language; an account of the sexual exploits of a gentleman named Walter in Victorian England, My Secret Life; and Memoirs of Dolly Morton, an 1899 novel about the erotic adventures of a Quaker woman in the American south before the civil war.

Teleny or The Reverse of the Medal, which is part of the collection, tells of the tragic relationship between a young Frenchman and a Hungarian pianist. Authorship of the novel has been attributed to Oscar Wilde and members of his circle in the late 19th century. “Nowadays we are more used to erotica, and fiction in general, including gay characters and storylines, but in the past this was pretty shocking,” said Smith. “Teleny is one of the earliest works of male gay erotic fiction in English and it was particularly shocking at the time.”

Harris’s Lists of Covent-Garden Ladies, meanwhile, is an 18th-century pocketbook directory of female sex workers in London that arranges its entries by name and address – “Miss Sp–nc–r, No 35, Newman Street” – and also includes information about the women’s physical attributes: Miss Sp—nc—r “is never so good a companion as when a little enlivened with the juice of the grape”.

Of a Miss Fr–m, from Berwick Street, it advises “she is now about nineteen, of a fair complexion, with blue eyes … tall and elegantly made, with well-formed projecting bubbies, that will, without being obliged to stays, keep their original ground”. Her “parts below”, it adds, “are very conveniently adapted to any size”.

Facebook Twitter Pinterest ‘All of these works are pretty much written by men, for men’ … title page of 1793 edition of Harris’s Lists of Covent-Garden Ladies. Photograph: British Library

“All of these works are pretty much written by men, for men. It’s to be expected, but looking back, that’s what is shocking, how male-dominated it is, the lack of female agency,” said Smith.

The Private Case collection has been accessible to the public through the British Library’s rare books collection since the 1960s, but the digitisation project with Gale means the titles will now be available to a much wider audience, by subscription to libraries and higher education institutions, or for free at the library’s reading rooms in London and Yorkshire. “It’s the final push to making them completely accessible,” said Smith.

Adrian Edwards, head of printed heritage at the library, said the collection “offers extraordinary insights into many facets of human sexuality over at least three centuries … By digitising this collection … we hope to make this collection visible and available as never before.”