BRIDGES. 
lowest; and if the ground be rocky, hard 
gravel, or stony, the first stones of the 
foundation may be laid on the surface ; but 
if the soil be soft sand, it will be necessary 
to dig till you come to a firm bottom. For 
the particular mode of constructing stone 
bridges, the reader is referred to the latter 
end of the article Building. 
We have many bridges of considerable 
note in our own country. The triangular 
bridge at Croyland, in Lincolnshire, which 
was erected about the year 860, is said to 
be the most ancient Gothic structure re- 
maining entire in the kingdom. There are 
two circumstances in the constructon of this 
bridge which render it an object of great 
curiosity. First, it is formed by three semi- 
arches, whose bases stand in the circumfe- 
rence of a circle, at equal distances from 
each other. These unite at the top ; and 
the triune nature of the structure has led 
some to imagine that it was intended as an 
emblem of the Trinity. Secondly, the as- 
cent on each of the semi-arches is by steps 
paved with small stones set edgeways, and 
is so steep, that none but foot-passengers 
can go over the bridge : horsemen and car- 
riages frequently pass under it, as the river 
in that place is but shallow. For what pur- 
pose this bridge was really designed, it is 
difficult, if not impossible, to determine. 
Utility, it is obvious, was one of the least 
motives to its erection. To boldness of 
design and singularity of construction it has 
more powerful claims ; and these qualities 
it must be allowed to possess, in as great a 
degree as any bridge in Europe. Although 
this bridge has been erected so many cen- 
turies, it exhibits no marks of decay. 
London bridge is in the old Gothic style, 
and had twenty small locks or arches ; but 
there are now only nineteen open, two 
having been lately thrown into one in the 
centre. It is 940 feet long, 44 high, and 
4 7 clear width between the parapets. The 
piers are from 15 to 35 feet thick, with 
starlings projecting at each side and end, so 
that the greatest water- way, when the tide is 
above the starlings, is 545 feet, scarcely 
half the breadth of the river; and below 
the starlings the 'water-way is reduced to 204 
feet, causing a dangerous fall at low water. 
London bridge was first built with timber 
in the reign of Ethelred, between the years 
993 and 1016 ; it was repaired, or rather 
rebuilt, of timber in 1163, and the present 
stone bridge was begun under King Hen- 
ry II. in 1176, and finished under King 
John in the year 1209. It is probable there 
were no houses on the bridge for upwards of 
200 years, since we read of a tilt and tour- 
nament held on it in 1395. Houses were 
erected upon it afterwards, but being found 
a great inconvenience and nuisance, they 
were removed in 1758, the avenues to 
the bridge Enlarged, and the whole made 
more commodious : the two middle arches 
were then thrown into one, by removing 
the pier from between them. The ex- 
pense of the repairs amounted to above 
80,000/. 
The bridges of Westminster and Black- 
friars, over the river Thames at London, are 
among the finest structures of the kind in Eu- 
rope. The former is 1220 feet long, and 44 
feet wide, having a commodious broad foot- 
path on each side for passengers. It con- 
sists of thirteen large and two small arches, 
fourteen intermediate piers, and two abut- 
ments. The length of each abutment is 
76 feet ; the opening of each of the smaller 
arches is 25 feet ; the span of the first of 
the large arches at each end is 52 feet, of 
the next 56 feet, and so on, increasing by 
four feet at a time to the centre arch, the 
span of which is 76 feet. The two piers of 
the middle arch are 17 feet wide, and the 
others decrease equally on each side, by 
one foot at a time, every pier terminating 
with a salient right angle against either 
stream. The arches are semi-circular, and 
spring from about the height of two feet 
above low water. The breadth of the river 
in this place is about 1220 feet, and the 
water-way through the bridge amounts to 
870 feet. The bridge was begun in 1738, 
and opened for passengers in 1750, at a 
neat expense of 218,800/. It is constructed 
of the best materials, and in a neat and 
elegant taste ; but the arches are too small 
in proportion to the quantity of masonry. 
Blackfriars bridge, nearly opposite to the 
centre of the city of London, was begun 
in 1760, and completed in ten years and 
three quarters, at a neat expense of 
152,840/. It is an exceedingly light and 
elegant structure ; but, unfortunately, the 
materials do not seem to be of the best 
kind, as many of the stones in the piers are 
decayed. The bridge consists of nine large, 
handsome, and nearly elliptical arches ; the 
central arch is 100 feet wide, and the four 
arches on each side, reckoning towards the 
shores, decrease gradually, being 98, 98, 
83, and 70 feet respectively, leaving a 
water-way of 788 feet. The whole length, 
from wharf to wharf is 995 feet, the breadth, 
of the carriage-way 28 feet, and that pf th§ 
/ 
