71 
with him, from the results of his spirited labours. Such is the 
brief history of the old time work which now belongs to the 
Manchester Ship Canal Company. 
If Brindley’s scheme of a century and a quarter ago was 
considered ‘a castle in the air,’ what would the present scheme 
have been thought? The Bridgwater Canal will pass over the 
Ship Canal a few yards higher up than the old stone aqueduct. 
This swing aqueduct, which is placed skew to the canal, is 
merely a watertight swing bridge. The approaches to the 
Barton Aqueduct on the north side, consist of a watertight 
wrought-iron bridge over Barton Lane. This simply consists of 
plate web girders with plate flooring. From Barton Lane to the 
canal there are sandstone walls. The bridge itself is of wrought- 
iron, and resembles Moore Lane swing bridge with these 
exceptions: it is of wrought-iron, it has equal arms and it is 
provided with a centre press. 
The aqueduct is 240 feet long, 19 feet broad, 33 feet deep at 
centre, and 29 feet at ends. The towing path is carried on 
brackets fixed to the strut of the main girder at a height of about 
10 feet above water level. The water is 6 feet deep. The 
difference in level of water in Bridgwater and Ship Canals is 
16 feet. The flooring consists of ordinary cross girders and 
straight plates with watertight joints. To make the aqueduct 
watertight when across the canal, inclined planes of cast-iron 
are fastened to each abutment and each end of the bridge. 
Between these planes, which are inclined 1 in 24, cast-iron skew 
wedges working between guides on the abutment are rammed 
tightly home by hydraulic pressure. India rubber facings are 
provided, and the greater the pressure on the wedge the tighter 
will the wedge be rammed. Each abutment and each end of 
the bridge are, of course, provided with gates, to be closed when 
the bridge is swung. These are closed and opened by hydraulic 
pressure. Those on the abutment are caisson gates 3 feet 
72 inches wide. This great breadth is to make the gate act as a 
displacer, so that there is only a few inches space between the 
two gates preparatory to it beg swung. The water is drained 
from between into the Ship Canal, and is let in from the Bridg- 
water Canal. All the gates being closed the wedges are raised, 
and the entire structure swung full of water. The weight of 
water is 763 tons when swung back, the wedges are rammed 
home, the space between the gates filled with water from the 
Bridgwater, the gates opened and traffic with the Bridgwater 
resumed. The aqueduct and bridge are pivoted on a centre pier 
in the middle of the canal, the latter being here widened for the 
purpose. This pier is of concrete 534 feet 6 inches long and 
35 feet wide. 
