Another wonderful discovery from the Public Domain Review: an eye test chart from a 1907 San Francisco optometrist George Mayerle. It not only featured international text and symbols, it had a positive and negative side.
[caption id="" align="alignnone" width="1024.0"]<a href="http://publicdomainreview.org/collections/george-mayerles-eye-test-chart-ca-1907/"><img src="http://tempblogfood.files.wordpress.com/2019/08/349d4-georgemayerlee28099seyetestchart28ca.190729.jpgGeorge+Mayerle%E2%80%99s+Eye+Test+Chart+%28ca.+1907%29?format=original" alt=" George Mayerle’s Eye Test Chart (ca. 1907) " /></a> George Mayerle’s Eye Test Chart (ca. 1907) [/caption]
