Holmes Stereoscope ‘The Stereo-Gothard’
The American Stereoscopic Company got the idea to combine the ease-of-use of the Holmes stereoscope design with the light-blocking benefits of the closed-box Brewster design and patented this Stereo- Gothard Attachment in 1901. You could buy this attachment as an add-on for a Holmes-style stereoscope or buy an all-in-one version called The Stereo-Gothard. Both are fairly rare but the Attachment version seems to be harder to find than the all-in-one. This creative design facilitated the viewing of the semi-transparent tissue stereoviews that the company also published.
