In September 1839, when the wires of the electric telegraph were carried as far as West Drayton, a distance of fifteen ... When a small magnetic bar is poised at the centre, so as to be free to move in any direction, one end points towards theanbsp;...
|Title||:||Chambers's information for the people, ed. by W. and R. Chambers|
|Author||:||Chambers W. and R., ltd|