" But that which excels all the rest is at Suentchcou fou, built over the point of an arm of the sea, without which the passage would be sometimes dangerous, even in a boat. It is 2500 Chinese feet in length and 20 in breadth ; it is supported by 252 strong piers, 126 on each side. All the stones arc of the same bigness, as at ell those which are laid from pier to pier, as those which are laid crosswise, insomuch that it is difficult to comprehend how stones of such an enormous size should be placed in that regular manner, or even raised on the high piers on which they lie. After this, there is nothing of the kind worth mentioning." The only conclusion to be drawn from the foregoing description of this work, which excels all the rest, is, that two rows of large stones or piers, (each row con sisting of 126,) have been set up across the shallow mouth of a river or arm of the sea ; that, along the top of these, other long stones have been laid horizontally, like wooden beams ; and lastly, that long stones have been laid crosswise upon those longitudinal beams, in the manner of joists in carpentry, or more probably close together, composing a compacted bed or road way. By dividing 2500, the total length in Chinese feet, by 127, the number of openings, it gives nearly 20 feet between centre and centre of the piers, so that after the thickness of the pier is taken away from the 20 feet, a moderate opening is left for the lintel to cover. The dimensions crosswise, correspond with the description as to the stones being of the same size, (at least as to length) ; for the breadth of the bridge is said to be 20 feet, and taking away the thickness of the two longitudinal beams, leaves the dimensions of the opening to he covered by the stones lying crosswise. It is therefore to the carrying from the quarry and raising stones of this magnitude, that the praise of ingenuity must be attributed ; there being nothing else in the mode of construction which has a claim to relined science, or great progress in the mechanical arts. The danger to boats passing must, no doubt, have arisen from the shallowness of the water, and the frequency and violence of the surfs.
From the following relation, extracted from the same work, there is reason to expect correct information. It is entitled, " An account of the Journey of the Fathers Boures, Fontenay,Gorbillou Le Compte, and Vesdelore, from the port of Ning Po to Pekin, with a very exact and particular description of all the places through which they passed, in the provinces of Tche-kiang, Kiang-nan, Chan-tong, and Pe-tcheli.
" It is in this agreeable place that the city of Chao king has its situation. In the streets arc a great num ber of canals, which give occasion for such a great num ber of bridges. They are very high, and have generally but one arch, which is SJ slightly built towards the top, that carriages never pass over them, which makes a great number of porters necessary. They pass over these bridges by a kind of stairs, of very easy ascent, and whose steps arc not more than three inches in ness. There are other sorts of bridges, made of stones 18 feet long, laid upon piles in the manner of planks.
There are many of these over the great canal very hand somely built." Again, " About four leagues. from Ilang-tcheou we crossed a village called Tan-si. It is built on both sides of the canal, on which arc also two quays, about 400 or 500 geometrical paces in length. They are formed of the same freestone which lines the sides of the canal. There are stairs for the convenicncy of every house, which arc much better built, and more uniform than those in the city. In the midst of the village is a fine bridge of seven large arches ; that in the middle is 45 French feet wide ; the 'rest diminish in proportion to the descent of the bridge. There are two or three great bridges of one arch only.
" We crossed a great village or country town, called Ovan Kiang king, of large extent. One nart communi cates with the other by means of a bridge of three great arches, very curiously built: the mildle arch is 45 French feet wide and 20 feet high." Of these arches, which are here termed large and great, we find the span to be only 45 feet ; an extent which, in Europe, would not be honoured with those appellations.
We have also heard of a bridge over a river named Laffrany in China, which joins two mountains together, said to be of one arch 600 feet span, and 750 feet in height ; but having no distinct authority for this, and its being so very unlike to those described in Duhalde's work, we mention it merely as a matter deserving of more enquiry.
But it is of real importance to notice the descrip tion given by Mr Barrow of the mode in which some of the arches in China are constructed. " Each stone from five to ten feet in length, is cut so as to form the seg ment of the arch, and in such cases there is no key stone ; ribs of wood fitted to the convexity of the arch, are bolted through the stones by iron bars fixed into the solid part of the bridge ; sometimes they are without wood, and the curved stones are mortised into long trans verse blocks of stone." In Egypt and India, from whence the western world derived the rudiments of many sciences and arts, the construction of the arch was totally unknown ; for the magnificent temples of the latter, and the splendid tombs of the former, were produced by cutting matter away in the manner of sculpture. There is no trace of the arch met with in the ancient works of Persia or Phoenicia ; and even the Greeks, who created a school of architec ture and sculpture, and carried it to the utmost degree of perfection of which it was capable, have a very doubt ful claim to the knowledge of the arch. It is certain they never used it as an external feature of their tem ples, much less in the construction of bridges over rivers ; and it has been observed, that the great Pericles, while he adorned the city of Athens with splendid edifices, never constructed a stone bridge over the small river Cephisus, although upon the most frequent ed road to that city. It is therefore to the Romans that the western world is indebted for this singularly useful application of architecture.