Page:The Bell System Technical Journal, Volume 1, 1922.pdf/9

and the necessity for sharpening the edge is obviated by allowing the glass to adhere to the flat portion of the disc only, care being taken to prevent its flowing around the edge. It is necessary to have a ring of glass on both sides of the seal in order to equalize the bending stresses

Fig. 3

Fig. 3

Fig. 4

Fig. 4