George Grant’s Difference Engine: How it Worked The difference machine of Grant was approximately 2.5 meters long and 1.5 meters high, weighing about 900 kg.

THE DIFFERENCE ENGINE: Charles Babbage and the Quest to Build the First Computer Doron Swade, Charles Babbage, . . Viking, $24.95 (352pp) ISBN 978-0-670-91020-5 ...

In the early 1800s, the English mathematician Charles Babbage proposed a machine called a difference engine that would compute and print automatically a large class of tables. Although Babbage's ...