Re: William H. Hanks
You should be able to borrow the book through your local library, Inter Library Loan (ILL)
Warren E. Grabau's "Ninety-Eight Days, A Geographer's View of the Vicksburg Campaign"
The site below list the libraries beginning with those nearest me, Sparks, NV
http://www.worldcat.org/title/ninety-eight-days-a-geographers-view-of-the-vicksburg-campaign/oclc/42652609&referer=brief_results