Melting Glass

 
Helen's brother Tzvi has a weekly gig teaching sciences in Tsfat,and asked me to melt some glass for him.Different glasses go at different temperatures,but most,like this sample,lose most of their form by 920 degrees or so.
Trying yet again to understand why glass is considered not-quite-a-solid [old window-panes,for example,being apparently thicker at the bottom,where the glass has slowly continued to flow...] I checked out Wikipedia/glass,where,among much useful and stimulating information,I came upon my friend Silver Nitrate,used as a colorant for glass..."the chemistry involved is complex and not well understood..." I think it's rather fine that there's still stuff like this that no-one understands.