Calculator

The first patent for a calculating machine was granted to the American Frank Stephen Baldwin in 1875. Baldwin's machine did all four basic mathematical functions and did not need to be reset after each computation. The second patent was given in 1878 to Willgodt Theophile Odhner from Sweden for a machine of similar design to Baldwin's. The modern electronic calculators are based on Baldwin's design.

In 1910, Babbage's son, Henry P. Babbage, built the first hand held printing calculator based on his father's Analytical Engine. With this machine, he was able to calculate and then print multiples of π to 29 decimal places.

In 1936, a German student, Konrad Zuse, built the first automatic calculating machine. Without any knowledge of previous calculating machines, Zuse built the Z1 in his parents' living room. He theorized that the machine had to be able to do the mathematical fundamentals. To do this, he turned to binary mathematics, something no other scientist or mathematician had contemplated. (The mathematics we use in every day life, decimal, is based on 10 digits. Binary mathematics uses two digits: 0 and 1.) By using binary mathematics, the calculating machine became a series of switches rather than gears, because a switch has two options: on (closed or 1) or off (open or 0). He then connected these switches into logic gates, a combination of which can be selected to do addition or subtraction. Zuse's third model (finished in 1941) was not only programmable, but hand held; it added, subtracted, multiplied, divided, discovered square roots, and converted from decimal to binary and back again. However, to Figure 1. Illustration by Hans & Cassidy. Courtesy of Gale Group. add it took a third of a second, and to subtract an additional three to five seconds. By changing his relays into vacuum tubes he believed he could speed his machine up 1,000 times, but he could not get the funding from the Third Reich government to rebuild his machine.