Hi, I'm trying to put together materials to demonstrate the Faraday Effect. I need to locate the supplier of some flint glass (glass with lead oxide or similar materials increasing the Verdet constant), that I could use in my lab. I had found this from Mansion Schools: http://www.mansionschools.com/prisms-science-laboratory-flint-glass-block-for-faraday-effect-br-u8474060-light-and-optics.html [Broken] but they are not shipping until May 8 for some reason. Does anyone have another source? Thanks.