Tide Predicting Machine No. 2 &x28;&x22;Old Brass Brains&x22;&x29;

This photo shows the largest of the three sections of Tide Predicting Machine No. 2, a special purpose mechanical analog computer for predicting the height and time of high and low tides. The gears on the left transmit power from the hand crank. The components on the right contribute to the computation of the time of high and low tides. The U.S. government used Tide Predicting Machine No. 2 from 1910 to 1965 to produce its tide predictions. The machine, also known as “Old Brass Brains,” uses an intricate arrangement of gears, pulleys, chains, slides, and other mechanical components to perform the computations. A person using the machine would require 2-3 days to compute a year’s tides at one location. A person performing the same calculations by hand would require hundreds of days to perform the work. The machine is 10.8 feet (3.3 m) long, 6.2 feet (1.9 m) high, and 2.0 feet (0.61 m) wide and weighs approximately 2,500 pounds (1134 kg). The operator powers the machine with a hand crank. The National Oceanic and Atmospheric Administration (NOAA) occasionally displays the machine at its facility in Silver Spring, Maryland.