Methyl methacrylate is probably the nearest approach to organic glass thus far developed. Its optical properties make it suitable for spectacle lenses, camera lenses, magnifying glasses, and protective goggles. Spectacle lenses are now being made to prescription by molding. It is estimated that 900 molds will supply the requirements of about 98 percent of the prescriptions. The excellent light transmitting quality of methyl methacrylate permits its use in edge lighting, advertising displays, and instrument dials. It is also used in inspection windows in various types of machinery where curved sections are necessary and where glass might be broken. A synthetic resin combining the properties mentioned, together with high tensile and impact strength, good dielectric properties, ultraviolet transmission, and resistance to water, oil, acids, and alkalies is an important contribution. The acrylates may be colored or have fillers added to give any desired translucency or opaqueness. They can be sawed, cut, blanked, turned, drilled, ground, polished, and sanded much the same as are nitrocellulose plastics. [Illustration: AIRPLANE COCKPIT ENCLOSURES OF CAST ACRYLATE RESIN. Source: Rohm & Haas Company, 222 W. Washington Square, Philadelphia, Pa.] [Illustration: SPECTACLE LENSES MOLDED TO OPTICAL PRESCRIPTION FROM ACRYLATE RESIN. Source: Rohm & Haas Company, 222 W. Washington Square, Philadelphia, Pa.] A new and interesting application of the acrylate resins is as molded reflectors in a system of indirect highway lighting. The reflectors are pressed from colorless, transparent methyl methacrylate resin and are 1⅝ inches in diameter. They are assembled in a pressed metal housing to form a double facing marker which is snap-locked to the top of an angle iron post. The posts are so located that the reflectors are accurately aligned 3 feet above the pavement edge. An installation has been made on U. S. Highway No. 16 between Detroit and Lansing, Mich., at a cost of about $340 per mile. The motorist provides his own light from his headlights which strikes the reflectors and is returned as a narrow beam of brilliant illumination. The chief of the United States Bureau of Public Roads states that this is a definite contribution to the safety and utility of the highways at night. The reflector is a group of tiny cube corners, over 300 in each disk. Each cube corner is a complete retrodirective optical system; a light ray entering the front surface is reflected from surface to surface of the cube and after the third reflection is directed back toward the headlight regardless of the entrance angle. If the cubes are made with a high degree of dimensional accuracy, the reflected light has a high candlepower, strong enough to be seen for a mile. Other uses for these resins are in sound recording records, dentures, telephone and radio transmitter diaphragms, novelties, and lighting fixtures.