"Brimstone. Always brimstone."
"Sullen lights glow green at the jetty's edge. Far above, the mountain's top flickers red: just for an instant."
Mount Palmerston is a large volcanic island that lies just southeast of Avid Horizon. The devils on the wrong side of their revolution have taken shelter here, under the name "The Brimstone Convention." The humans on the island do not seem to mind the devils, but the soul trade thrives.
A certain Wistful Deviless resides here.
Many Palmerstons exist, as many mountains and islands are named after the famous Henry John Temple, 3rd Viscount Palmerston. Temple was the Prime Minister of the UK from 1859-1865 and had a long and famed career as a politician throughout the Victorian Era, and in Fallen London's alternate universe, he no doubt would have been in London when it fell. Due to his reputation, diplomacy, and political activity, explorers named many sites after him.
One such site in particular are the Palmerston Atolls in the Cook Islands of Polynesia, 15 small islands which are in fact the top of a volcano, the island of Palmerston being the only one populated.