Be it known that I, SIEGFRIED MARCUS, of the city and county of Philadelphia, State of Pennsylvania, have invented and produced a new and original Design for Prismatic Glass Lights, of which the following is a specification.

My new design for prismatic glass lights is shown in the accompanying drawings, in which—

Figure 1 is a perspective view of the light looking down upon the prismatic face, and Fig. 2 is a transverse sectional view of the same on the line A A of Fig. 1 and slightly enlarged.

The essential feature of the design resides in the prismatic face, which is composed of notched prismatic ribs a b c d e f g h i j k, arranged in a series of broken concentric circles about a central boss m, or, in other words, the prismatic rib of each circle is not continuous, but is broken up into parts, so that each ring is made up of alternate prismatic ribs and plane surfaces. The prismatic ribs in each ring are adjacent to the plane surfaces in the adjacent rings, and vice versa, and as the diameters of the rings increase the length of the prismatic ribs and plane surfaces

correspondingly increase. As shown, each ring is composed of four prismatic ribs and four plane surfaces arranged diametrically opposite, so that the ribs of alternate rings, as a, c, e,, g, i, and k on the one hand and b, d, f, h, and j on the other, are included between the same radial lines. The end edges of the prismatic portions are inclined and provided with notches n, and the series of prismatic ribs are provided with V-shaped notches o, arranged on radial lines and of increasing size and depth from the center. The ribs j at the outer edge of the sides of the plate are of smaller height than the adjacent ribs, and the upper surface is concave. On the corners are pyramidal projections l.

What I claim as new, and desire to secure by Letters Patent, is—

The design for a prismatic glass light substantially as described and shown in the accompanying drawings.

In testimony of which invention I have hereunto set my hand.