The tale recounts the visit to Earth of a being from a planet circling the star Sirius and his companion from the planet Saturn. This story and Voltaire's 'Plato's Dream' (another early precurser of Sci-fi) were probable influences upon H.G. Wells.
The technique of using an outsider to comment on aspects of western culture was popular at this period, and was used again by Voltaire in Zadig, and by Montesquieu in Lettre persanes (Persian Letters), amongst others.
See also: Jonathan Swift, Gulliver's Travels; Mary Shelley, Frankenstein, The Last Man; Thomas More, Utopia.