The yacht <i>Ariel</i> was built by Thornycroft's yard at Chiswick, and it was featured in the November 4, 1870 edition of the periodical <i>Engineering</i> on page 329, accompanied by some illustrations, including this one.
Unknown illustrator of the time
Engineering, 1870-11-04, page 329, <a rel="nofollow" class="external text" href="http://www.gracesguide.co.uk/images/8/8a/Eg18701104.pdf">link to file at gracesguide.co.uk</a>