xxxviii Trans. Acad. Sci. of St. Louis. 



Mr. George M. Wright Avas elected an active member. 



Dr. C. Barck read the paper of the evening, on " The 

 History of Spectacles." He divided the subject into two 

 parts, the development of the industrial art, and the evolution 

 of the scientific selection. 



In regard to the former, it is an open question, whether the 

 Chinese invented glasses prior to the Europeans. Of the 

 ancient nations of western Asia, we possess only one relic, 

 namely a convex lens of rock crystal which was dis- 

 covered among the ruins of old Nineveh by Sir Layard. 

 To the Egyptians, Greeks and Romans glasses were unknown. 

 The latter assertion does not agree with the common opinion, 

 as expressed in the belief, that Nero was near-sighted and 

 used glasses. But this is due to a misinterpretation of a 

 passage of Pliny, as proven at length by the reader of the 

 paper. During the first twelve centuries of the Christian era 

 there is no mention of spectacles ; they were invented at the 

 end of the thirteenth century by two Italians, Armati and Spina, 

 either independently or conjointly. This is proven by a 

 number of documents. The essayist then dwelt upon the 

 gradual spread of their use, and the improvement of the 

 frames and lenses. At first only convex lenses were used, 

 concave ones being employed about two centuries afterwards. 

 Cylindrical lenses for the correction of astigmatism, which 

 had been discovered by Thomas Young in 1801, were devised 

 by the astronomer Airy in 1827. Bifocals were invented and 

 first used by Benjamin Franklin, 1785. 



As to the selection of the appropriate lenses, this was at 

 first done by the peddlers who sold them. Physicians for a 

 long time paid no attention to it. Even after the epochal 

 work of the astronomer Kepler had opened a new era in 

 optics by demonstrating the physiology of the act of vision, 

 1604, physicians maintained their reserved attitude, and 

 considered it below the dignity of their profession to have 

 anything to do with the selection of glasses. It was only in 

 the middle of the last century that the change took place. 

 This was due mainly to the labors of Helmholtz and Donders, 

 who laid the foundation for the adjustment of lenses accord- 



