This meant that there was to calculate the logarithms to make the tables, and therefore it was necessary also to realise many calculations. In 1.620, Edmund Gunther invented one formulates to use the logarithms of one more a simpler way although not so precise. This consisted of placing the logarithms in a straight line and the multiplications and divisions were realised adding or removing segments through a pair of splitters. This was known like the Gunther method, a time later William Oughtred used two movable scales that Rule called of Calculation. The scales of the Slide rule graduate according to the logarithms of the amounts that are had to calculate. In century XVII there was a division between the analogical and Digital computers in. Being those that used the Slide rule like analogical, since the values which they were obtained with this were approximated and Digital those that used the abacus, since the calculations realised with this were exact and independent of their physical dimensions, as large as the accounts, or the length of the wires.

The slide rule has been an analog computer of great success, until in the Seventies was replaced by the electronic calculators. The same inventor of the logarithms John Napier, invention also a mechanical apparatus that was called bones of Napier by the similarity that these had with the bones and so that they were constructed of that material. These apparatuses got to be very precise and very economic. Napier also introduced the decimal point, which is still used in ours days to separate the integral numbers of the decimal. 1,4 GEAR MECHANISMS. PASCAL and inventive LEIBNITZ.El and Leonardo l$da Vinci painter, were the one who drew up the ideas for a mechanical sumadora. Average century and later the philosopher and French mathematician of 19 years of age hardly called Blaise Pascal, invented and constructed in century XVII a mechanism (Pascaline) which used to conduct arithmetical operations.