Electrical experiments. 19th-century diagram of various devices to be used in electrical experiments. The device across top is an electrostatic generator, operated by turning the handle at far right. The other devices all relate to experiments that can be carried out with the electric charge generated with the machine. At lower left (figure 5) is what is described as an artificial 'thunder-house'. Diagram from 'The Works of James Ferguson, F.R.S.' (1823) containing works by Scottish astronomer and instrument maker James Ferguson (1710-1776).