§4.17.1Caesar his de causis quas commemoravi Rhenum transire decreverat; sed navibus transire neque satis tutum esse arbitrabatur neque suae neque populi Romani dignitatis esse statuebat.
Caesar for these reasons which I have mentioned had resolved to cross the Rhine; but he deemed that crossing by boats was neither safe enough, nor did he judge it to be consistent with his own dignity or that of the Roman people.
§4.17.2Itaque, etsi summa difficultas faciendi pontis proponebatur propter latitudinem, rapiditatem altitudinemque fluminis, tamen id sibi contendendum aut aliter non traducendum exercitum existimabat.
Therefore, although the greatest difficulty of constructing a bridge was presented on account of the breadth, rapidity, and depth of the river, still he thought that he must strive for this, or otherwise not transport his army.
§4.17.3Rationem pontis hanc instituit.
He established this plan for the bridge.
Tigna bina sesquipedalia paulum ab imo praeacuta dimensa ad altitudinem fluminis intervallo pedum duorum inter se iungebat.
He joined together two joists at a time, each a foot and a half thick, sharpened a little at the bottom, and proportioned to the depth of the river, leaving an interval of two feet between them.
§4.17.4Haec cum machinationibus immissa in flumen defixerat fistucisque adegerat, non sublicae modo derecte ad perpendiculum, sed prone ac fastigate, ut secundum naturam fluminis procumberent, §4.17.5iis item contraria duo ad eundem modum iuncta intervallo pedum quadragenum ab inferiore parte contra vim atque impetu fluminis conversa statuebat.
When he had, by means of engines, lowered these into the river, secured them, and driven them home with pile-drivers, not straight down like piles in a perpendicular line, but sloping and leaning forward, so as to incline in the direction of the current of the river, he also placed opposite to these, at a distance of forty feet on the lower side, two other joists joined in the same manner, turned against the force and rapid current of the river.
§4.17.6Haec utraque insuper bipedalibus trabibus immissis, quantum eorum tignorum iunctura distabat, binis utrimque fibulis ab extrema parte distinebantur; §4.17.7quibus disclusis atque in contrariam partem revinctis, tanta erat operis firmitudo atque ea rerum natura ut, quo maior vis aquae se incitavisset, hoc artius inligata tenerentur.
These two sets of piles were kept apart by beams two feet thick let in from above, as wide as the distance between the joints of the joists, and were held fast at each end by two brackets on either side; since these were kept apart and secured in opposite directions, so great was the strength of the work and such the nature of the structure, that the greater the force of the water that pressed against it, the more tightly they were held bound together.
§4.17.8Haec derecta materia iniecta contexebantur ac longuriis cratibusque consternebantur; §4.17.9ac nihilo setius sublicae et ad inferiorem partem fluminis oblique agebantur, quae pro ariete subiectae et cum omni opere coniunctae vim fluminis exciperent, §4.17.10et aliae item supra pontem mediocri spatio, ut, si arborum trunci sive naves deiciendi operis causa essent a barbaris missae, his defensoribus earum rerum vis minueretur neu ponti nocerent.
These were covered with timber laid in a straight direction, and were boarded over with long poles and hurdles; and besides, piles were driven obliquely on the lower side of the river, which, placed below as a buttress and connected with the whole work, might break the force of the stream; and other piles also at a moderate distance above the bridge, so that, if trunks of trees or vessels were floated down by the barbarians for the purpose of destroying the work, the force of such things might be diminished by these defenders, and they might not injure the bridge.