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ami were desirous of destroying it, they found the mortar so hard, that they were obligedto give up the undertaking.
Bridge at Ratisbon , over the Danube , began in 1135, by Henry the Superb, Duke ofBavaria, consists of fifteen arches, and its total length is 994 feet. The piers rest on piles,and are defended by jetties and large starlings. It is only 21 feet 4 inches wide; it ispaved with square stone; the footways are only 1 foot in width, and the parapets areformed of flag-stones, placed on edge, united by iron cramps, and run with lead. At aboutone-third of the length there is a descent upon an island, by means of a staircase containedbetween two walls.
The arches are semicircular, and are from 33 feet to 53 feet span.
Bridge of Zwettau , over the Torgau , on the Elbe , was built by King Augustus , in1730. It consists of twelve arches; of the eleven piers five have starlings; the othershave only a set-off. The fall of this bridge is very considerable.
Bridge at Wurtzbourg , over the Meine, consists of eight semicircular arches, 32 feet 9 inchesspan ; the starlings of the piers are semicircular, and rise to the level of the parapet; thework is simple, and very solidly constructed. Statues are placed on the piers, and amongthem is that of St. John Promucena, regarded in all Germany as a patron of bridges.
Bridge of Kosen , on the Saal, near Naumbourg , presumed to have been constructed inthe tenth or twelfth century, consists of eight arches; the five in the middle of the currentare pointed, the others are semicircular.
Bridge of Mossen on the Mulde , in Saxe, is composed of three semicircular arches; wasconstructed from 1715 to 1718, by Daniel Poepelmann, under the reign of Augustus .
Bridge at Nurembourg, called ABC over the Pregnitz, built under the Emperor ('liarlcs VI., who laid the first stone, was finished in 1728 ; it is formed of two arches 4(1feet span. In the interior of the pier is a vaulted passage; this pier is surmounted bytwo obelisks, erected to the honour of the emperor; the parapets are ornamented with pe-destals surmounted by a ball.
Bridge of the Boucherie, at Nurembourg, over the Pregnitz, constructed in 1599 byPeter Carlo, presented many difficulties in its foundations; it consists of a single segmentalarch, 97 feet 2 inches span, and 12 feet 9 inches high ; the thickness of the arch is only 4feet, the breadth of the bridge is 40 feet.
We have seen that wherever Imperial Rome extended her sway, she has left memorialsof those useful works which have rendered her name immortal among the nations, and itis not too much to conclude, that after the long night of barbarism which succeeded theoverthrow of her mighty power, when civilisation again dawned, they would be the guidefor whatever improvements might be required, and we have sufficient evidence that theywere the models from which the after inhabitants derived the knowledge they possessed onthe subject; but we can hardly say that the engineer w'as fully called into practice earlierthan the middle of the seventeenth century, about which period Bernard Forrest de Belidorwrote his “ Architecture hydraulique,” w hich awakened great attention, and laid the foun-dation for those theoretical studies, which had been entirely neglected by practical menthroughout Europe . This writer, an officer in the artillery, w r as requested to suggestsome system to guide the military engineer, which eventually led to the establish-ment in the year 1720, of the Ponts et Chaussces, first composed of an inspector-general, orchief architectural engineer, three other inspectors, and twenty-one assistant engineers. Thenumber was afterwards increased to twenty-five and twenty-eight, and in the year 1770,fifty inspectors were added, taken from the sub-engineers, the numbers of which dependedupon the necessities of the service. This important and erudite body, acquainted both withtheory and practice, directs’the education of all who intend to act as civil engineers, or un-dertake the construction of roads and bridges; and they require those who aspire to thesuperintendence of these works to possess a knowledge in geometry, mechanics, mineralogy,and the natural properties of all the materials employed in the arts of construction.
Among the engineers of this institution are registered the names of the most celebratedmathematicians of France , who have contributed to the formation of a theory upon what-ever subject they may have been employed. Such an establishment for carrying out the
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