OF REMOTE AGES. 349 
(which Herodotus says they were not,) it may 
well be doubted whether they could be made of 
adequate strength, without being nearly as heavy 
as the block they had to lift. Diodorus* speaks 
of the inclined plane having been used in their 
construction, and one commentator conceives the 
machines mentioned by Herodotus to have been 
pulleys. The mass of combined labour which a 
system of slavery places at the command of the 
master, with two such powers as the pulley and 
the inclined plane, would certainly be equal to the 
construction of all the buildings in question, and 
I conceive scarcely any other means would; and 
if these powers were known and used in so remote 
an age, what an impression does this give us of 
the advanced civilization of a people who had 
invented and employed them a thousand years 
before our era! 
On the whole then, the conclusions we may 
draw, respecting the stupendous fortifications we 
have been considering, are reduced to this limited 
amount : 
That they all took their origin before the birth 
of authentic history, and that some of them have 
* B. iv. p. 73. 
