[Footnote 1: Paper read before the British Association.--_Elec.
Engineer._]
By W.H. Preece, F.R.S.
1. I have already on two occasions, at Newcastle and at Leeds, brought
this subject before Section G, and have given the details of the
length and construction of the proposed circuit.
I have now to report not only that the line has been constructed and
opened to the public, but that its success, telephonic and commercial,
has exceeded the most sanguine anticipations. Speech has been
maintained with perfect clearness and accuracy. The line has proved to
be much better than it ought to have been, and the purpose of this
paper is to show the reason why.
The lengths of the different sections of the circuit are as follows:
London to St. Margaret's Bay 84.5 miles.
St. Margaret's Bay to Sangatte (cable). 23.0 "
Sangatte to Paris. 199.0 "
Paris underground. 4.8 "
-----
Total. 311.3 "
The resistances are as follows:
Paris underground. 70 ohms.
French line. 294 "
Cable. 143 "
English line. 183 "
---
Total (R) 693 "
The capacities are as follows:
Paris underground. 0.43 microfarads.
French line. 3.33 "
Cable. 5.52 "
English line. 1.32 "
----
Total (K). 10.62 "