By observing of the melt course and by analyzing the measurements of glass samples, the feasibility of nepheline syenite as raw materials for the green float glasses was discussed.

The method can detect the warp by observing the distance between the two images reflected from the precision sheet glass and the standard plate for the same reference object.

The experiment results show that observing jet appearance with the double reflecting mirrors system is feasible as long as the vacuum of the glass tube can meet the requirement of experiment.