Bonhams : HELMHOLTZ SOUND SYNTHESIZER. HELMHOLTZ, HERMANN VON. 1821-1894. Chemnitz: Max Kohl, c.1905.
Hexen und Hexenmeister – Community – Google+
AC/DC ░ mercury arc rectifier , Tesla .
Charles Babbage's design for a mechanical computer. In 1991, British scientists worked on these notes and created Difference Engine No. accurate to 31 digits based on Babbage’s specifications. They were able to work on logarithm and trigonometry calculations with this model. Only two devices were built from Babbage’s designs, and one of them is currently on display at the “Computer History Museum” in Mountain View, California.
Antique Bank Vault Door - Two people open and close the Vault. Weighs 22 Tons.