Final answer:
The king of Brobdingnag reacts with horror to Gulliver's stories of England, being particularly appalled by their use of gunpowder and viewing the English as 'odious vermin'.
Step-by-step explanation:
The king of Brobdingnag's reaction to Gulliver's stories of England is one of horror. When Gulliver tells the king about the history, government, and the use of gunpowder in England, the king is not impressed. Instead, he is so appalled, especially by the use of gunpowder and weapons of mass destruction, that he refers to Gulliver and his fellow countrymen as 'odious vermin.' The king cannot fathom why such devices and practices would be used for destruction and dominance. His reaction showcases a stark contrast between Brobdingnagian and English society, providing a commentary on the violence and ambition inherent in Gulliver’s homeland.