NOTE 1: This construction is common only with trádúcó, tráició, and tránsportó. The preposition is sometimes repeated with compounds of tráns, and usually with compounds of the other prepositions. The ablative is also used: -
NOTE 2: The secondary object may be retained with a passive verb: as, - Belgae Rh=enum traducti sunt (B. G. ii. 4) the Belgians were led over the Rhine.
NOTE 3: The double construction indicated in § 395 is possible only when the force of the preposition and the force of the verb are each distinctly felt in the compound, the verb governing the direct, and the preposition the secondary object.
But often the two parts of the compound become closely united to form a transitive verb of simple meaning. In this case the compound verb is transitive solely by virtue of its prepositional part and can have but one accusative, - the same which was formerly the secondary object, but which now becomes the direct. So tr=aici=o comes to mean either (1) to pierce (anybody) [by hurling] or (2) to cross (a river etc.):
In these examples hominem and Rhodanum, which would be secondary objects if tráiécit were used in its primary signification, have become the direct objects. Hence in the passive construction they become the subjects and are put in the nominative: -
The poetical tráiectus lóra (Aen. ii. 273), pierced with thongs, comes from a mixture of two constructions: (1) eum tritiecit lóra, he rove thongs through him,[Perhaps not found in the active but cf. tráiecto fúne (Aen. v.488).] and (2) eum tráiécit lóris, he pierced him with thongs. In putting the sentence into a passive form, the direct object of the former (lóra) is irregularly kept, and the direct object of the latter (eum) is made the subject.