The debt we owe to Henry as a scientist

The name of Joseph Henry is connected with the most brilliant epoch in the history of the science of electricity. To appreciate it fully, let us briefly describe the state of this science prior to the beginning of this glorious epoch — I refer now to the discoveries of the eighteenth century. Stephen Gray´s discovery of electrical conduction in 1729 was the broadest foundation for subsequent work. Franklin´s discoveries and philosophical speculations in the realm of electrical phenomena gave a tremendous impulse to further research. Galvani´s fortunate discovery of the existence of electric force in the contact region of heterogenous bodies closes this period.