strong enough to withstand, besides the weights rushing through it, the
natural gales and artificial squalls of wind to which, throughout its
entire length, and at its fearful height, it is permanently to be
exposed."

Notwithstanding these "incomprehensible" speculations, the tubes are
abundantly strong to sustain the pressure of the heaviest trains, even
were they to stand still in the middle of the bridge. It is calculated
that each tube, in its weakest part, would sustain a pressure of four or
five thousand tons, "support a line of battle ship, with all her
munitions and stores on board," and "bear a line of locomotives covering
the entire bridge." The bridge was completed, and the first train passed
through it March 5th, 1850. The total cost of this gigantic structure
was only £601,865.




GLORY OF ANCIENT ROME.


Ancient Rome was built upon seven hills, which are now scarcely
discoverable on account of the vast quantities of rubbish with which the
valleys are filled. Pliny estimates the circumference of the city in his
time at 13,000 paces (which nearly agrees with modern measurements), and
the population at 3,000,000. Rome was filled with magnificent public
edifices, temples, theatres, amphitheatres, circuses, naumachiæ,
porticos, basilicæ, baths, gardens, triumphal arches, columns, sewers,
aqueducts, sepulchres, public and private palaces, etc.