392 THE FORMATION OF EGYPT. 



between the convent and the lake-dwelling, because in the 

 narrower part of the valley, in which the latter is situated, 

 the gain may have been more rapid ; but if we only go to the 

 point at which the basin contracts, we shall have a distance 

 of 3000 metres, which would, upon these data, indicate a 

 minimum antiquity of 6750 years. This calculation assumes 

 that the shape of the bottom of the valley was originally uni- 

 form. M. Morlot agrees with Prof. Gillieron in believing that 

 this was the case, and from the general configuration of the 

 valley it seems to me also to be a reasonable supposition. 

 Moreover, the soundings taken by M. Hisely in the Lake of 

 Bienne show that the variations in depth are but of slight 

 importance. We must not, indeed, attach too much impor- 

 tance to these two calculations ; but they appear to indicate 

 that 6000 or 7000 years ago Switzerland was already inha- 

 bited by men who used polished stone implements, but how 

 long they had been there, or how many centuries elapsed 

 before the discovery of metal, we have as yet no evidence to 

 show. 



A still greater antiquity was obtained by Mr. Homer as the 

 result of his Egyptian researches, which were undertaken at 

 the joint expense of the Eoyal Society and the Egyptian 

 Government. Every year the Nile, during its periodical over- 

 flow, deposits a certain amount of fine mud, and even as 

 long ago as the time of Herodotus, it was inferred that Egypt 

 had been formerly an arm of the sea, filled, up gradually and 

 converted into dry land by the mud brought down from the 

 upper country. 



In the great work on Egypt which we owe to the French 

 philosophers who accompanied Napoleon's expedition to that 

 country, an attempt was made to estimate the secular eleva- 

 tion thus produced, and it was assumed to be five inches in a 

 century. This general average was consistent, however, with 

 great differences at different parts, and Mr. Horner, therefore, 



