With the development of semi-indirect illumination, bowls and globes have become to be extensively used associated with high wattage gas-filled lamps.
Fixing the lamp in improper position with respect to bowl or globe may sometimes injure them in relatively short period owing to some local over heating. thus causing cracks on their surface as shown in figure 1.
Authors have given the relative positions of lamp and dust cover if any with respect to certain glass bowl to instal within its safety-temperature rise and also disc, isied the' uniformity of its surface brightness for the safety-relative position of lamp with respect to bowl (let. mined from the standpoint now refered).
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