Spencer Company Eye Test Chart on Board antique magic lantern slides if one should be so

if one should be so lucky as to have a living relative born in 1931

I assume the intent was for this to be made into a rug or mat

While certainly a functional base for a dramatic floral arrangement

and is pretty rare

and a little foxing here and there

Spencer Company Eye Test Chart on Board antique magic lantern slides if one should be soI believe this eye test chart dates to the mid to late 1940s; I have found some references to the Spencer Company of Mount Vernon that produced it from around then, including in Popular Photography magazine advertising photography equipment. I have found no matches for it out there anywhere though, so am not sure how much traction it gained as among optometrists though with its terrific mix of text and patterns and color it seems like it would have