TRANSACTIONS OF SECTION G. 745 



of the different portions of the line, and the arrangement and material of the 

 wires. 



Speech is already commercially maintained hetween Paris and Brussels (190 

 miles); Paris and Lille (158 miles); Paris and Rouen (80 miles); Paris and 

 Havre (135 miles) ; Paris, Lyons, and Marseilles, the latter being a distance of 

 nearly 600 miles, but in all cases over aerial wires, excepting for a short length 

 (about 2 miles) of underground work in Paris. 



The author has experimented on the cables between Dover and Calais, between 

 Holyhead and Dublin, and between South Wales and Wexford. The conditions 

 to be fulfilled are very simple. The circuit must be metallic, the material must be 

 copper, and the product of the resistance of the line (It) and its capacity (K) must 

 not exceed a certain figure. It has been determined roughly by experiment that 

 when 



KR = 



We have thus a .species of Beaufoy's scale applied to telephonic communication. 



A circuit approaching as nearly as possible one between London and Paris was 

 made on an artificial cable, and it was found lo comply with the requirements. 



An actual circuit was then made from Worcester, through 27 miles of the 

 Jjondon underground system, to Baldock, on the Great Northern Railway, giving 

 similar electrical conditions, and with the same result. It may be considered as 

 absolutely settled that speech is possible between London and Paris. 



In the United States speech is maintained between New York and Boston, 350 

 miles, and in many instances to distances exceeding that between London and Paris, 

 but they have not been compelled to surmount the difficulties of underground wires 

 at each end, and of a cable in the middle. 



7. On the Purification of Sewage and Water contaminated tvith Organic 

 Matter hij Electrolysis.^ By W. Webster. 



The paper was divided into four sections, bearing on the different values of the 

 methods for the oxidation of organic matter in solution, leading up to the action 

 produced by the electric current. 



1. By natural processes due to the action of atmospheric oxygen dissolved in 



water. 



2. By the action of the soil, due to oxygen in its pores, and also to the iron 



oxides therein acting as purveyors of o.xygen. 



3. By artificial disinfectants, represented by chemicals such as chromic acid, 



permanganates, chlorine, &c., chlorine having a powerful oxidising 

 action upon all organic matter, living or dead. 



4. The electric current produced by mechanical or chemical power. The 



fact that water and the salts contained therein are easily decomposed, 

 provided the current of electricity is of sufficient intensity, is an 

 explanation of the whole .system. The changes taking place in sewage 

 when electrolysed depend chiefly on the splitting up into their consti- 

 tuent parts of sodium, magnesium, and other chlorides, nascent o.xygen 

 and chlorine being set free at the positive, and the bases at the negative 

 pole, 

 (rt) The adaptation of the electric current to filters and filter beds in such a 

 manner that putrefaction cannot take place in the pores of the filtering 

 media owing to the constant presence of nascent oxidising agents, 

 the filter always remaining clean, because the impurities are consumed 



' Printed in extenso in the Electrician, October 4, 1889. 



