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618,280 · Manning · "Window and Light-Reflecting Device" · Page 2 Home  > Prism Glass  > Patent Index  > Page 2

618,280: 2 of 3

In Fig. V is shown the exact shape of the angular side of the prismatic glass, being two angles α and β and the sides Q R, R S, and S T. The relative length of the sides and of the angles being dependent upon the conditions of the light distribution—that is, for each angle of visible horizon—there exists a form of glass two sides of which are parallel and the other two angular, which will allow the greatest quantity of light to be distributed in a certain direction. For moderate-length rooms the angles α and β are approximately forty-five degrees each, and R S is parallel to the other side.     The theoretical increase of light given by my window construction and attachment thereto is seen in Fig. I. Suppose C and D (the mirrors) to be equal in size to the window and a line drawn across from the bottom of the window to the upper edge of D just touches the lower edge of the visible horizon. Then all rays of light, like R' R', include all the light which falls direct on the window. With my attachment an equal number of rays, like R'' R'', are once reflected against the window. An equal number of rays, like R''' R''', are reflected from C against the window.

Another set of rays RIV RIV also reach the window by two reflections from both C and D. These last two rays of R''' RIV are of great importance. By the arrangement shown practically double the amount of light (other things being equal) will be thrown into the room than would be the case if only one reflector were used. The question of determining the angles of prismatic glass to deliver the greatest quantity of rays throughout the desired space is therefore one of the conditions of the size of the reflectors and the angle of visible horizon.     Having described my invention, what I claim as new and original is—     The combination of a window, a bracket below said window, a horizontal reflector supported by said bracket and a second reflector mounted on hinges and simulating a blind on the outside, substantially as described.     In testimony whereof I affix my signature in presence of two witnesses. CHARLES E. MANNING. Witnesses:     PHILLIPP WERNER,     ALBERT PORTER.