This card is to be viewed through a Telebinocular. If the viewer sees both pig and dog at the same time, eyesight is sufficient. Even better, though, is to see the dog over the pig. Complete failure, according to the instructions, is to see a dog only, a pig only, or both a dog and a pig, but not at the same time.
This is a warm-up card. When looking at it through the Telebinocular, the viewer will see the turkey behind bars. (A sad image, though, don't you think?)
This card tests color blindness.All three cards are part of the Keystone Diagnostic Series created by the Keystone View Company in Meadville, Pennsylvania. Era unknown. (Yes, another swap find. Can you see how much fun the swap is? One never knows what interesting thing might appear...)
You might want to check this out for information about the company: http://www.yellowstonesteroviews.com/publishers/keystone.html
ReplyDeleteIt indicates that as interest in stereo viewers dropped off (seemingly in the 1920s?) the company started to emphasize the educational value of their scenic images and also the diagnosis of eye problems.
I also found a description of a set like this at www.thejumpingfrog.com but will send you that separately as I don't seem to be able to paste into this box.
Thank you for this interesting information and the website referral, Cathy! I hope you'll accept the post of Official Blog Researcher because you add such good background material. It is an honorary position, so you only have to research the stuff you want to research.
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