some were all of iron so cunningly linked that they might flow like slow rivers of metal or coil themselves around and above all obstacles before them , and these were filled in their innermost depths with the grimmest of the orcs with scimitars and spears ; others of bronze and copper were given hearts and spirits of blazing fire , and they blasted all that stood before them with the terror of their snorting or trampled whatso escaped the ardour of their breath ; yet others were creatures of pure flame that writhed like ropes of molten metal , and they brought to ruin whatever fabric they came nigh , and iron and stone melted before them and became as water , and upon them rode the balrogs in hundreds ; and these were the most dire of all those monsters which melko devised against gondolin .