Reading stone

A reading stone was an approximately hemispherical lens that was placed on top of text to magnify the letters so that people with presbyopia could read it more easily. Reading stones were among the earliest common uses of lenses.

Reading stones were developed in the 8th century, following the development by Abbas Ibn Firnas of a process for converting sand into glass. Glass could be shaped and polished into stones used for viewing.

单词	Reading stone
释义	Reading stone 原声例句 TED演讲（音频版） 2020年2月合集 The first vision aid was called a reading stone and was invented over 1,000 years ago. 第一个助视器被称为阅读石，是在 1000 多年前发明的。英语百科 Reading stone A reading stone was an approximately hemispherical lens that was placed on top of text to magnify the letters so that people with presbyopia could read it more easily. Reading stones were among the earliest common uses of lenses. Reading stones were developed in the 8th century, following the development by Abbas Ibn Firnas of a process for converting sand into glass. Glass could be shaped and polished into stones used for viewing.
随便看	Sollya的意思 sollyite的意思 solman的意思 solmargin的意思 solme的意思 solmen的意思 solminol的意思 solmisate的意思 solmisation的意思 solmisation的意思 solmizate的意思 solmization的意思 solmization的意思 solmization syllable的意思 Solms的意思 Soln的意思 Soln.的意思 Solna的意思 Solnechnogorsk的意思 Solnechnogorskiy Rayon的意思 Solnechnyy的意思 sol的意思 Solnhofen limestone的意思 Solnice的意思 Solnicol的意思