Page from <i>The Progressive Machinist</i> by William Rogers, (1903 T. Audel &amp; Co.) showing a monkey wrench and a Stillson or pipe wrench, and explaining the difference.
William Rogers (publisher Theo. Audel &amp; Co.)
<a rel="nofollow" class="external text" href="https://books.google.com/books?id=DLdBAAAAIAAJ&amp;pg=PA172&amp;dq=monkey-wrench+stillson-wrench+intitle:machinist&amp;lr=&amp;as_brr=0&amp;ei=rq6jSPOZFob-swPP8aWeBQ">The Progressive Machinist: A Practical and Educational Treatise, with Illustrations</a>