[138] His words run as follows: “I think that it may be prudent, when designing bridges for rivers of great width, to introduce some strong piers, which in case of need may serve as abutments, putting them at distances of three or four arches apart. Moreover, this arrangement will enable us to construct long bridges in different parts successively, and each part may be considered as a complete bridge, having its own independent abutments; but strict care should be taken not to contract the beds of rivers by using too many thick piers.” One of Perronet’s immediate predecessors, the engineer Gabriel, built a bridge of this sort, over the Loire at Blois. He spaced his plan into eleven fine arches, and erected two abutment piers, placing them at four bays from each bankside, and leaving three bays between them. By this means his bridge was divided into three independent parts. [139] Examples: See the index under the headings “Trezzo,” “Ticino,” “Pavia,” and “Ammanati’s Trinità at Florence.” [140] See Degrand’s “Ponts en Maçonnerie,” Tom. 2, p. 24, note 3. See also Dalquié’s translation of Kircher’s book, published at Amsterdam in 1670. There is a reference to iron in a bridge on p. 288, but Degrand’s information must be taken from the following passage: “L’on voit un pont dans la Province de Junnan, qu’on a basti sur un torrent, lequel roule ses flots impetueux dans le panchant d’une profonde vallée. C’est un commun sentiment qu’il fût basti en l’an 65 après la naissance de Jesus Christ par l’ordre de l’Empereur Mingus, sorti de la famille Hame; il n’est pas fait de brique ny de pierre; mais on a attaché de grosses chaisnes [chaînes] à ces deux montagnes qui vont d’une extremité à l’autre, au-dessus desquelles on a mis des ais pour faciliter le passage des voyageurs. Ce pont, qui a vingt chaisnes, a 20 perches de long qui font 140 pieds: l’on dit que quand beaucoup de personnes passent dessus, ou qu’il y a quelque grand fardeau, il branle si fort qu’il fait peur à ceux qui y sont” (p. 289). This description is vivid, and M. Degrand regards the chains as chains of iron. He says: “Kircher mentionne l’existence ... d’un pont composé de chaînes de fer supportant, en travers d’une vallée profonde, un tablier en charpente d’une grande longueur, c’est-à-dire un véritable pont suspendu, ayant précédé sans doute de plusieurs siècles les ponts du même genre construits à l’époque moderne en Europe et aux États-Unis.”