ON THIS DATE IN 1743: Benjamin Franklin’s “Eclipse Hurricane” unlocked the key to storm movement. The storm became know as the ‘Eclipse Hurricane’ because it struck on the night of a lunar eclipse.
Benjamin Franklin was residing in Philadelphia and was set to make observations of the predicted eclipse, but the clouds from the storm interfered. Franklin observed that the winds accompanying the storm were from the northeast and assumed the storm had come from that direction and so had also interfered with lunar observations made by his brother back in Boston. He was surprised to later find that the eclipse had been visible in Boston and that the storm had struck there hours afterward. Franklin concluded the storm had moved contrary to surface winds.
His observations were confirmed by another hurricane which traveled up the east coast of the Colonies in October of 1749, which Franklin was able to trace by using newspaper accounts from various cities along the storm course.
From ABC 33/40 Weather Blog.