Many persons suppose, and maintain, that the grandeur of the monuments
of the ancients, and the great size of the stones they employed for
building purposes, prove that they understood mechanics better than the
moderns. The least knowledge in mechanics, however, will show this
opinion to be erroneous. The moderns possess powers which were unknown
to the ancients, as the screw, and the hydraulic press, the power of
which last is only limited by the strength of the machinery. The works
of the ancients show that they expended a vast deal of power and labor
to gratify the pride and ambition of kings; but the moderns can do all
these things much easier, and in far less time, whenever they deem it
proper. There was nothing in ancient times to be compared with that
daring, ingenious, and stupendous monument of engineering skill--the
Britannia Tubular Bridge, across the Menai straits--projected, designed,
and built by Robert Stephenson, the famous English engineer. He had
previously built a similar but smaller structure--the Conway Tubular
Bridge.