Leonardo Torres Quevedo read-only conditional branching floating-point arithmetic arithmometer Electromechanical Arithmometer machine arithmetic analytical engine
In his work Essays on Automatics published in 1914, Leonardo Torres Quevedo wrote a brief history of Babbage's efforts at constructing a mechanical Difference Engine and Analytical Engine. He described the Analytical Engine as exemplifying his theories about the potential power of machines, and takes the problem of designing such an engine as a challenge to his skills as an inventor of electromechanical devices. The paper contains a design of a machine capable of calculating completely automatically the value of the formula 




a

x


(
y
−
z

)

2




{\displaystyle a^{x}(y-z)^{2}}

, for a sequence of sets of values of the variables involved. The whole machine was to be controlled by a read-only program, which was complete with provisions for conditional branching. He also introduced the idea of floating-point arithmetic. In 1920, to celebrate the 100th anniversary of the invention of the arithmometer, Torres presented in Paris the Electromechanical Arithmometer, which consisted of an arithmetic unit connected to a (possibly remote) typewriter, on which commands could be typed and the results printed automatically, demonstrating the feasibility of an electromechanical analytical engine.
