E. A. Wallis Budge 
By Nile and Tigris [PDF ebook] 
A Narrative of Journeys in Egypt and Mesopotamia on Behalf of the British Museum Between the Years 1886 and 1913

Whilst the greatest effort has been made to ensure the quality of this text, due to the historical nature of this content, in some rare cases there may be minor issues with legibility. Merchants have told me that, provided the Tigris flowed close by it as in ancient times, and not a mile and a half from it as at present, Nineveh would be a far more convenient place for a frontier market than Mosul. Indeed, it is probable that the development of Western Nineveh into the large town which Sapor I called Mawsil, was due to the fact that the Tigris removed itself from the west wall of the City further to the west, or that one of the arms of the river flowing parallel with it became the main stream.