The Laing Co., of Detroit, Mi., manufactured planetariums based on the patent (#578,108) issued to Alexander Laing in 1897. Frank Trippensee (a Laing employee) and his brothers bought the firm in 1905, and turned the simple string and pulley instrument into one that used a chain drive and gears. That form—for which Frank Trippensee received patents in the United States (#881,875) and Canada in 1908—proved remarkably successful and remains in production to this day. This wonderful example is in great shape and is fully functional. It measures 17 inches long and 13 1/2 inches high. Mounted on metal base. The earth is paper based, the two planets are wood, the sun is plastic. The compass works fine. The earth rotates with chain and gears. Very minor signs of wear, no dents or dings. Basically this unit accurately duplicates orbital relationship of Sun, Earth, Moon, Venus, as well as many other concepts through chain-driven gears rotating the arms of the unit. These planetariums are durable and reliable gear and ladder chain driven so that the earth maintains its 23-1/2° axis, revolves around the sun and rotates on its axis, all at the same time. The moon revolves around the earth and keeps its one face toward the Earth. Venus also revolves around the sun, and can be positioned by hand, as well, to show phases and where it is located as the morning or evening star. The Trippensee models have been produced for over 100 years and provide many visual demonstrations that clarify the relationships of these elements of the solar system, in motion, for children and adults interested in learning more about the universe.