how did gulliver tried to win favour of the king in ch7,part 2 ,explain.

Gulliver had told the king about an invention, discovered between three to four hundred years ago to make a certain powder into a heap of which, the smallest spark of fire falling would kindle a big mountain in one moment. A proper quantity of such a powder when rammed into a hollow tube of brass or iron and propelled with speed and violence could decimate the surrounding areas and lay them to waste. The king however was horrified by such an idea and Gulliver's proposal to make it was dismissed.