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Patents: 289 of 530	UNITED STATES PATENT OFFICE. JAMES G. PENNYCUICK, OF TORONTO, CANADA, ASSIGNOR TO JOHN LAWRENCE SPINK AND THOMAS WALTER HORN, TRUSTEES, OF SAME PLACE.	James G. Pennycuick 4 of 12
VAULT-LIGHT. SPECIFICATION forming part of Letter Patent No. 568,789, dated October 6, 1896. Application filed November 5, 1895. Serial No. 568,014. (No model.)

To all whom it may concern:     Be it known that I, JAMES G. PENNYCUICK, sanitary engineer, of the city of Toronto, in the county of York and Province of Ontario, Canada, have invented a certain new and Improved Vault-Light, of which the following is a specification.     The object of my invention is to devise a vault-light which is protected from grinding by the feet of passers-by and which will throw the light transmitted both horizontally and downwardly; and it consists, essentially, of a light cast with a series of teats on its upper surface and two prisms on its under surface having different reflecting angles, and of such other details of construction as are hereinafter more specifically described, and then definitely claimed.     Figure 1 is a perspective view showing four lights in position in a portion of the iron supporting-frame. Fig. 2 is a sectional perspective view of one of the lights.     In Fig. 2, A is a flat glass tile forming the body of the light. The under surface B (indicated by dotted lines) lies in a horizontal plane when the light is in position. As pavements in which these lights are to be used are set at a slight pitch, the upper surface B of the tile is set at a small angle to the under surface, so that while the under surface is horizontal the upper surface corresponds with the pitch of the pavement. The angle may of course be varied to suit the pitch of the pavement in which it is to be used.     D is a rabbet formed around the edges of the light, with which the ribs of the supporting iron frame engage, as hereinafter described.     E E are a series of teats, preferably nine in number, cast on the upper surface of the tile. These may be of any shape that will answer their purpose, which is to prevent the feet of the passers-by grinding the surface of the light and thus materially reduce its transparency.     On the under surface B of the tile two prisms F and G are cast. The prism F is preferably so proportioned that the angles at the base of its cross-section are respectively eighty-five degrees and forty-five degrees, as shown in the drawings. The other prism, G, is

so proportioned that the angles at its base are respectively eighty-five degrees and fifty degrees, while its apex extends below the level of the apex of the prism F. From this construction it follows that light passing downward through the flat glass tile A is reflected horizontally by the reflecting-surface H of the prism F, while light striking the reflecting-surface I of the prism G is reflected obliquely downward, as indicated in dotted lines in Fig. 2.     I do not wish to confine myself to the exact proportions and angles shown, as these may be varied slightly without materially decreasing the utility of the light, but those shown I consider as preferable.     In Fig. I, J is the iron frame, provided with cross-ribs K and L. The ribs K, running in the direction in which the light is cast by the prisms, are deep and give strength to the frame, while the ribs L, running across the direction in which the light is shown, are made shallow, so as to intercept as few rays as possible.     The sides of the frame J and the supporting-ribs K and L are provided with shoulders M, on which the lights rest, being secured in position by any suitable cement.     From this construction it will be seen that I have devised a vault-light which is suitable for a pitched pavement, in which the surface is protected from grinding by the feet of passers-by, in which the light transmitted is reflected not only horizontally but also obliquely downward, and that the supporting-frame intercepts the smallest possible amount of the reflected rays.     What I claim as my invention is--     1. A glass tile, having two prisms on its under surface, arranged one behind the other, the reflecting-surface of one prism being at an angle of substantially forty-five degrees to the horizontal, and the reflecting-surface of the other prism being at an angle of substantially fifty degrees to the horizontal, the said prisms reflecting the rays of light in the same general direction, and each having a non-reflecting surface in front of the reflecting-surface, substantially as described.     2. A glass tile, having two prisms on its