electrons. In the late nineteenth century, the nature of the energy emitted by the discharge between high-voltage electrodes inside an evacuated tube—cathode rays—attracted the attention of many physicists. While the Germans thought cathode rays were waves, the British and the French believed they were particles. Working at the Cavendish Laboratory, established by Maxwell, J. J. Thomson directed a dedicate experiment demonstrating that cathode rays were in fact negatively charged particles, now called electrons. The experiment enabled Thompson to calculate the ratio between the magnitude of the charge and the mass of the particle (). In addition, because the ratio was the same regardless of the metal used, Thompson concluded that electrons must be a constituent of all atoms. Although the atoms of each chemical elements have different numbers of electrons, all electrons are identical. Computer science and logic Inspired by the explorations in abstract algebra of George Peacock and Augustus de Morgan, George Boole published a book titled An Investigation of the Laws of Thought (1854), in which he brought the study of logic from philosophy and metaphysics to mathematics. His stated goal was to "investigate the fundamental laws of those operations of the mind by which reasoning is performed; to give expression to them in the symbolical language of a Calculus, and upon this foundation to establish the science of logical and construct its methods." Although ignored at first, Boolean algebra, as it is now known, became central to the design of circuits and computers in the following century. The desire to construct calculating machines is not new. In fact, it can be traced all the way back to the Hellenistic Civilization. While people have devised such machines over the centuries, mathematicians continued to perform calculations by hand, as machines offered little advantage in speed. For complicated calculations, they employed tables, especially of logarithmic and trigonometric functions, which were computed by hand. But right in the middle of the Industrial Revolution in England, Charles Babbage thought of using the all-important steam engine to power a mechanical computer, the Difference Engine. Unfortunately, whilst Babbage managed to secure government funds for the construction of the machine, the government subsequently lost interest and Babbage faced considerable troubles developing the necessary machine components. He abandoned the project to pursue a new one, his Analytical Engine. By 1838, he had worked out the basic design. Like a modern computer, it consisted of two basic