The author studied on the dulabilities of chrome-green and carbon-brown glasses. The results were summerised as followed:
Green glasses, which were coloured by minute quantities of chrome oxide or other chrome salts, and brown glasses, which were coloured by carbon, showed the better dulabilities than those which were prepared from the batches of the same compositions except colouring materials as fomer.
Tnese phenomena were considered to be caused by neither volatilisation of alkalies nor other changes of glass-compositions. Because the analysis of the above mentioned coloured and no colour glasses showed that the compositions of those glasses were regarded to be the same.
