3-4 Tandem . . . fatigatis, i.e. after H.’s attempt to pass by a side-way over a glacier failed.
4 in iugo, i.e. on the higher level where the road was broken away.
6 ad rupem muniendam = to cut a way through the rock. Munire (cf. moenia) = lit. ‘to wall,’ ‘to build.’ So munire viam = to make a road. Hannibal widened the narrow ledge of road by making a sort of terrace.
9 detruncatis = trimmed, (lit. ‘lopped off’), i.e. cleared of branches.
11-12 infuso aceto. Limestone rock might be softened by vinegar, which the posca, the soldiers’ regular drink of vinegar and water, would supply. Polybius does not mention this.
13-14 molliuntque . . . clivos = relieve the steepness of the descent by gently-sloping zigzag paths. Anfractus, from ambi + frango.
References. Polybius, iii. 54-56; Ihne, i. 171-179.