66 Mr. Ware’s Design for 
This work was finished in 260 days, and then the river was turned 
into its ancient channel; so that Semiramis could go privately 
from one palace to another, under the river. She made also two 
brazen gates at each end of the vault, which continued to the time 
of the kings of Persia, the successors of Cyrus.” 
In 1798, atunnel, 900 yards in length, was projected to pass 
under the Thames, to unite Tilbury, in Essex, with Gravesend, in 
Kent, at an estimate of only £15,955. Subscribers were obtained 
to promote the undertaking, by whose means an engine-house and 
steam-engine were erected, and a shaft dug, about 146 feet deep, 
when the engine-house was burnt, and the operations were aban- 
doned. 
In 1805, an Act of Parliament (45 Geo. 3. cap. cxvii.) was 
obtained, to construct a tunnel under the Thames, at the Old 
Horse Ferry, about 23 miles below London Bridge, and to raise 
£140,000, and a further sum of £60,000, in all £200,000. A 
shaft, 76 feet deep, was sunk, and a driftway, 5 feet high, 
3 feet wide at the bottom, and 2 feet 6 inches at the top, was 
extended, under the direction of Mr. Trevetheck, a Cornish 
miner, 1011 feet from the south shore, under the bed of the 
Thames, when sand and water burst in upon the workmen, 
and further progress was suspended. The powers given by this 
act are now, by lapse of time, void. In 1809, notice was given, 
idea* that the Euphrates was 5 stadia in breadth, see lib. ii, c,1. The Eu- 
phrates was turned out of its channel, in order to effect this purpose. Hero- 
dotus, who is silent concerning the tunnel, says, that the river was turned 
aside in order to build a bridge. Diodorus describes a bridge also. ‘here is 
an absurd story told, in both these historians, respecting the disposal of the 
water of the river during the time of building the bridge. According to them, 
the water was received into a vast reservoir, instead of the obvious and usual 
mode of making a new channel to conduct the river, clear of the work con- 
structing in its bed, into the old channel, at a point lower down t.” 
* Diodorus merely states, that the bridge built by Semiramis was 5 stadia in 
length. Bridges are frequently five times aslong as the width of the river 
they stride. 
+ This story, from the vastness of the reservoir, may be true. Local circum: 
stances may have compelled Semiramis to adopt this apparently extrayagant 
mode of removing the water of the Euphrates from the site of the tunnel. 
