Nathaniel Hawthorne's Sci-Fi

You probably know the name Nathaniel Hawthorne. Often described as one of the greatest fiction writers of the 19th century, and master of the allegorical and symbolic tale, he penned The Scarlet Letter and The House of Seven Gables, and was a close friend of Herman Melville, Merson, Thoreau, and many of the greatest thinkers and writers of his time.
What you may not know is that, among his many stories, are several that prefigure sci fi as a genre. This book collects six of his finest: a fountain of youth that fixes nothing, a watchmaker's mechanical butterfly, a garden built to weaponize beauty, and a world emptied of every human soul, among others.

In the rejuvenation tale Dr. Heidegger's Experiment (1837), the waters of the fountain of youth are tested on an elderly, and initially ecstatic, group.
In the post-apocalyptic The New Adam and Eve (1843) two new humans wander the ruins left by the old civilization.
In the bioengineering tale The Birthmark (1843), a scientist strives to remove the single blemish of imperfection from his beloved, not realizing the implications of his success.
History's first robitc insect appears in The Artist of the Beautiful (1844).
In the bioengineering tale Rappaccini's Daughter (1844), a doctor obsessed with poisons tries to bring great power to his daughter.
In P.'s Correspondence (1845), we find an Alternate history from a London where Byron, Keats, and Shelley never died young.