16 Feb
2008
16 Feb
'08
4:04 a.m.
ard at p850ug1.demon.co.uk (Tony Duell) writes:
I would say relays were definitely available in 1900.
Yes, they were -- my 1871 copy of Robert M. Ferguson's "Electricity"
describes them in the selection about telegraphic applications:
http://offog.org/stuff/ferguson-relay.jpeg
--
Adam Sampson <ats at offog.org> <http://offog.org/>
