A beginner's question: when using an ablative of means/method where the means/method in question is a verb, does that verb take the gerund ablative form? This is the sentence which prompted the question:
"..ac prope Tiberim fluvium, quem prae se armentum agens nando transierat,.."
Which I translate as:
"..and by the river Tiber, which driving the herd before him he had crossed by swimming,..".
Have I understood this correctly?