Data for more than 970 analyses of container glasses made during 150 years in 37 countries have been collected and analysed. The data obviously included containers made by hand, as well as by machine, from green, white and amber glasses. Compositions developed along two lines, one being green and brown glasses coloured by manganese; such glasses were characterised by low alkali content compensated by increased RO and higher Al2O3 contents. The other, younger, line includes white glasses historically descended from old "forest glasses" and closely related to amber glasses. The compositions of both lines converged gradually, so that from about 1970 all container glasses have fallen within a narrow range of compositions, differing in little but their colouring oxides. Differences between particular producers and countries have decreased a great deal.
