TOPOGKAPHY OF CORNWALL. 345 



trusted entirely to Ptolemy'^ leadership, and the next jjlace is 

 taken by those who have been misled by fancied etymologies. 



Now a cursory examination of Ptolemy will show that there 

 is a very marked diiference — as indeed was inevitable — in the 

 accuracy of his latitudes and his longitxides. He is very little 

 over a degree out in his estimate of the length of Great Britain 

 from the Land's End to Dunnet Head ; but he is four degrees in 

 excess of the estimate of the much smaller distance between the 

 Land's End and the JSTorth Foreland ; and places which are really 

 on the same meridian of longitude are set down as differing from 

 each other nearly 14 degrees. Moreover, while Ptolemy averages 

 nearly two degrees in excess in the latitudes given to places in 

 this western promontory, they are relatively placed with much 

 greater exactness, the total range of comparative error being 

 about 40 minutes. But the longitude is quite another matter. 

 Between the Land's End and Exeter 6|- degrees are allowed 

 instead of less than 2;^ ; while between the Land's End and Hart- 

 land 3 degrees are given instead of 1. All in fact that Ptolemy's 

 longitudes can do, at any rate in the West, is to indicate relative 

 position ; and to pay further attention to them would only 

 ensure error. 



There is no reasonable doubt that Isca Damnoniorum is our 

 modern Exeter. Let us see how this fact will enable us to 

 approximate the position of its sister towns. 



The latitude assigned to Voliba is 25 minutes less than that 

 of Exeter, and we may take the longitude so far into account as 

 to accept the statement that it is the most westerly of the group. 

 Kunning along the latitude indicated we find ourselves about 

 the middle of Cornwall, and we shall see by and bye, from other 

 considerations, that the most likely place is Polruan. 



To Uxella the same latitude as Exeter is given, and so far 

 as longitude is concerned it would be east of Voliba. If Uxella 

 was a port (and all Ptolemy's western towns appear to have been 

 near the sea) this would bring us to the north coast, and indicate 

 in all likelihood the estuary of the Camel , which would be well 

 within the ordinary range of error. It is a curious coincidence, 

 if nothing more, that in this locality we have Uxella echoed in 

 such nam's as Perth Izaak and Lezizick, Zanzidgie, Canalidgie, 

 and St. Issey ; and there is ample evidence that the Camel was 



