“Mercurial” means changeable or temperamental. Gulliver is implying that the Brobdingnagians are not able to see all sides of an issue. However, this is ironic because their government actually functions more smoothly due to the stability and practicality of their laws. Gulliver attempts to criticise the Brobdingnagian government, but in reality, the reader is only convinced more of its superiority to European government.
"A strange effect of narrow principles and short views!..."See in text(Part II - Chapter VII)
This is ironic because the king’s argument that cannons are inhumane and unnecessary is actually very logical and virtuous, which Swift points out using satire. It is actually Gulliver who is being narrow-minded here, siding blindly with British warfare tactics rather than seeing the compelling reasoning behind the king’s critique.
"propagate the breed..."See in text(Part II - Chapter VIII)
Recall that Gulliver used these exact words to explain why he wanted to bring the Lilliputian people and animals to England. However, now that Gulliver is the one at a disadvantage, he likens it to being a “disgrace.” Note though, that Gulliver does not reflect on his treatment of the Lilliputians here even though the parallel may be obvious to a reader.
"his royal displeasure...."See in text(Part III - Chapter IX)
The king is another example of a leader who uses physical power to punish and degrade his citizens. Gulliver’s ironic comment about the “clemency” of the king is Swift’s way of satirizing the king’s cruel methods. His actions clearly do not indicate his decency as a ruler.
