Barlow's law

[2] Barlow undertook his experiments with the aim of determining whether long-distance telegraphy was feasible and believed that he proved that it was not.

[1] The publication of Barlow's law delayed research into telegraphy for several years, until 1831 when Joseph Henry and Philip Ten Eyck constructed a circuit 1,060 feet long, which used a large battery to activate an electromagnet.

"[1] In 1827, Georg Ohm published a different law, in which current varies inversely with the wire's length, not its square root; that is, where

Heinrich Lenz pointed out that Ohm took into account "all the conducting resistances … of the circuit", whereas Barlow did not.

Ohm's law in modern usage is rarely stated with this explicit term, but nevertheless an awareness of it is necessary for a full understanding of the current in a circuit.