It should not have a current passed through it by the external cell of more than a fraction of a milliampere, or else it becomes wounded and unsensitive.
"Hertzian Wave Wireless Telegraphy"
John Ambrose Fleming
Its sensibility ought to be such that it is actuated by a tenth of a milliampere, and, if possible, even by less.
"Hertzian Wave Wireless Telegraphy"
John Ambrose Fleming
To stimulate us to greater improvement, Edison hung up a card which showed the results of tests in milliampere-hours given by the experimental elements as we tried them with the various grades of nickel and iron we had made.
"Edison, His Life and Inventions"
Frank Lewis Dyer and Thomas Commerford Martin