for it was the design of the kings that maedhros should march openly over the anfauglith with all his strength , of elves and of men and of dwarves ; and when he had drawn forth , as he hoped , the main armies of morgoth in answer , then fingon should come on from the west , and so the might of morgoth should be taken as between hammer and anvil and be broken to pieces ; and the signal for this was to be the firing of a great beacon in dorthonion .