THEORY of the E4RTH. 299 



out a parallax, as to calculate the deftruction of the folid land 

 without a meafure correfponding to the whole. 



THE defcription which POLYBIUS has given of the Pontus 

 Euxinus, with the two oppofite Bofphori, the Meotis, the Pro- 

 pontis, and the Port of Byzantium, are as applicable to the 

 prefent ftate of things, as they were at the writing of that hi- 

 ftory. The filling up of the bed of the Meotis, an event 

 which, to POLYBIUS, appeared not far off, mud alfo be con- 

 fidered as removed to a very diftant period, though the caufes 

 ftill continue to operate as before. 



BUT there is a thing in which hiftory and the prefent 

 ftate of things do not agree. It is upon the coafl of Spain, 

 where POLYBIUS fays there was an ifland in the mouth of the 

 harbour of New Carthage. At prefent, in place of the ifland, 

 there is only a rock under the furface of the water. It muft be 

 evident, however, that the lofs of this fmall ifland affords no 

 proper ground of calculation for the meafure or rate of wafting 

 which could correfpond to the coaft in general ; as neither the 

 quantity of what is now loft had been meafured, nor its quali- 

 ty afcertained. 



LET us examine places much more expofed to the fury of 

 the waves and currents than the coaft of Carthagena, the nar- 

 row fretum, for example, between Italy and Sicily. It does 

 not appear, that this paflage is fenfibly wider than when the 

 Romans firft had known it. The Ifthmus of Corinth is alfo 

 apparently the fame at prefent as it had been two or three 

 thoufand years ago. Scilla and Charibdis remain now, as they 

 had been in ancient times, rocks hazardous for coafting veflels 

 which had to pafs that ftrait. 



IT is not meant by this to fay, thefe rocks have not been 

 wafted by the fea, and worn by the attrition of moving bo- 

 dies, during that fpace of time ; were this true, and that thofe 

 rocks, the bulwarks of the land upon thofe coafts, had not 

 been at all impaired from that period, they might remain 



P p 2 for 



