A Lens Attachment for Lamps

1901 Scientific American  
THE SPONTANEOUS BREAKING 01' AN INKWELL. If a mass of molten metal or of glass be allowed to cool suddenly, the outer portions will be chilled while the inner portions are still hot, and the thinner
doi:10.1038/scientificamerican02091901-84b fatcat:tz3hovctzjdfhivb3m3ynea4hm