These legions are all mentioned in our author. Before the time that Vespasian was emperor, Josephus relates, _Bell. jud._ II. 16. that king Agrippa, in his speech to the Jews, in Nero’s time, and before that emperor called the XIVth legion from Britain, speaks of four legions then in Britain. I have this further to add, in relation to our map: when I began to consider it with that attention which it deserves, I was a little surprised to see the river Trent, instead of falling northward into the Humber, to be carried eastward through Lincolnshire, into the East sea. I presently suspected, this was owing to the artificial cut of the Romans, called Fossdike, part of the Carsdike; which Fossdike is drawn from Torksey at the Trent, to Lincoln: there it meets the river Witham coming from the south, and proceeds eastward toward Boston. Ever since I was capable of observation, I often took notice, that the whole flat, or fenny country of Lincolnshire, has a gentle declivity, or natural descent eastward. This is owing not only to the sea lying that way, but is the case of all levels in the whole globe: the cause must be asserted to be the earth’s rotation upon its _axis_; which observation I printed, long since, in my _Itinerarium Curiosum_. It is a principle in nature, that, when a globe is turned on its _axis_, the matter on the surface flies the contrary way to its motion. The philosophers call this improperly a _conatus recedendi ab axe motus_: it is not owing to an endeavour of matter to fly the contrary way, but to the innate inactivity of matter that resists the motion; does not readily follow it. But it is evident from hence, that the earth, receiving its motion before the surface was perfectly consolidated, the moistish matter would be left westward, as far as it could be, and produce an extended and gentle declivity on the east; and at the same time, by stiffening, would render the west side of all hills steep. This is a fact throughout the whole globe. Hence it is, that all plains and levels have naturally their descent towards the east; and hence it is, that the river of Witham, from Grantham side, running northward to Lincoln, readily takes its course thence eastward, to meet the ocean over the fenny level.