Gullivers Travels by Part 3 Chapter 3 Page 12

But there is still indeed a more weighty reason, why the kings of this country have been always averse from executing so terrible an action, unless upon the utmost necessity. For, if the town intended to be destroyed should have in it any tall rocks, as it generally falls out in the larger cities, a situation probably chosen at first with a view to prevent such a catastrophe; or if it abound in high spires, or pillars of stone, a sudden fall might endanger the bottom or under surface of the island, which, although it consist, as I have said, of one entire adamant, two hundred yards thick, might happen to crack by too great a shock, or burst by approaching too near the fires from the houses below, as the backs, both of iron and stone, will often do in our chimneys. Of all this the people are well apprised, and understand how far to carry their obstinacy,