Jungermanns indeling in capita van Herodotus’ Historiën

The division in capita of Herodotus’ Histories goes back to the edition of Gottfried Jungermann of 1608. What were his model, motive, and method when undertaking this editorial task? The answers to the first two questions can be found in one of his prefaces (Ad candidum lectorem), the relevant section of which is here offered in a transcription and translation. The last question can only be tentatively answered by looking at the actual division itself, since he does not say anything about it, except that he wanted to keep together speeches.