History, evolution, operation and propaganda, of all the devices of calculating machines: contóstilos, calculation rules and machines of calculating mechanical. You can also calculate really with two old machines.

If you want all this information in a book, 6 PowerPoint and more in a CD ROM Spanish version, you can have it for just 25 Euros. 

Contact me in the following address: JOSEPBALSACH@telefonica.net

I decided to start writing the book: "DE LA MANO AL CÁLCULO ELECTRÓNICO", 4.000 años calculando (FROM THE HAND-TYPING TO THE ELECTRONIC CALCULATION, 4.000  year calculating) since I checked it did not exist any book about calculating machines written in Spanish and few in foreign languages.  The book  is about all the instruments the men used to calculate since the prehistory up to nowadays. It explains, by chronological order, who invented these instruments, a summarise explanation about the marks, history, curiosities and the mechanical functioning. Copier of old advertising, instruction manuals, pictures, patents, web sites.... up to more than 300 different marks.  You can also calculate really with two old machines

This book is more extensive than the book written by Ernest Martin: "THE CALCULATING MACHINES (DIE RECHENMASCHINEN). THEIR HISTORY AND DEVELOPMENT.

You can find this book in the following web site: http://www.mipaginapersonal.movistar.es/web3/calculating/

Please do not hesitate to contact me in: JOSEPBALSACH@telefonica.net