74 
THE TELEGRAPH. 
carriers are transported every quarter of an hour from one office 
to the other with the least possible loss of time. Of course, 
this is unnecessary when only a very short time is required for 
the removal of the obstruction. 
If it should happen that the interruption is prolonged, the 
plan is adopted of sending the trains in either direction instead 
of circularly. In this case the compressed air apparatus will 
have to supply double the quantities necessary for the regular 
working. There is a loss of time in changing from one mode 
of working to the other ; therefore when the interruption can be 
removed in less than four hours, the use of carriages ever the 
interrupted section is preferred. 
The system of lines in Paris.— M. Ch. Bontemps gives 
very precise details concerning the formation of the Paris system 
of lines. In 1866 a trial line connecting the Bourse (Exchange) 
and the Grand Hotel was established and worked regularly with 
air compressed by the water supply of the city. The tubes 
were afterwards extended from the Grand Hotel to the rue 
Boissy d’Anglas, then to the central station, rue de Grenelle- 
Saint-Germain. This office was afterwards joined to the Bourse 
by a second communication through the sub-offices of the rue 
des Saints-Peres, the Hotel du Louvre (rue de Rivoli), the rue 
Jean-Jacques-Rousseau and so on to the Bourse.- These works 
were finished in 1867. 
Numerous branches have since been established, and the 
extensive works which are about to be commenced in order to 
complete the Paris system will be used by the postal service as 
well as by the telegraphic. Figs. 33 a and 33 b exhibit the 
general arrangement of the pneumatic apparatus in an im¬ 
portant station. 
Pneumatic tubes are not in use in the provincial towns of 
France, with the exception of Marseilles, where the central 
office, situated in the Place du Prefecture, has been connected 
with the Bourse by a tube 866 yards in length. 
Together with the descriptions of the London and Paris 
systems, we shall give one of the Berlin system, so that our 
readers may be able to compare the pneumatic tube despatch 
services of the principal capitals in Europe. 
Pneumatic tubes first came into use at Berlin on the 1st of 
December, 1876, and they were employed both for the postal 
