Post by John Higgins
Since the work was published in the 1940s it's unlikely to have been digitized, and I can't quickly locate any copies on major used-book websites.
I now recall that the UK section of Archive CD Books (when it was still operating) entered into an agreement with the Harleian Society to publish CD copies of virtually all of the "visitation series" publications of the society (including the ones still under copyright, except perhaps the "new series" volumes). It appears that they are still available through other parts of the Archive CD Books organization. Specifically the "Yorkshire Pedigrees" volumes are here, as a single CD:
And at another site as well:
Since these volumes are unlikely to appear on sites such as Google Books or the Internet Archive in the foreseeable future, the CD versions could be a sensible purchase for interested parties.