516 
NATURE 
| March 30, 1882 
The War Office exhibit, which, in the face of flattering | illustrated by the stall of the South-Eastern Railway 
expectations, and in spite of interested accounts, must be 
pronounced a very disappointing one, and comparatively 
insignificant when contrasted with the display made by | 
foreign governments in Paris, has nevertheless a novel 
feature in the equipment of a mountain telegraph train 
for service in the field. This is carried by three dummy 
mules, one of which bears two drums containing about 
three miles of insulated wire for laying on the ground, 
another bears the working tools, and a third the shelter- 
tent, furniture, and apparatus, constituting the mountain 
of fire. ‘‘Sounders” are used in preference to “inkers” 
as receiving instruments, and telephones are added, be- 
cause when a wire is cut by the enemy, or otherwise 
UY 
Company, whose engineer, Mr. C. V. Walker, F.R.S., 
was one of the first to see the importance of the telegraph 
for the prevention of accidents and the furtherance of 
trafflc. Mr. Walker’s original electromagnetic semaphore, 
now used in block signalling, his plan for intercommuni- 
cation between passengers and guards, and his train- 
describer for announcing to the next station the character 
| of the approaching train, are all worthy of close attention. 
Mr. Spagnoletti’s apparatus, as used on the Great 
Western Railway, including his indicator for showing if a 
lamp is “in” or “out,’’ is also very interesting. So, too, 
is the new system of Messrs. E. K. Winter and Craik, for 
working single lines on the block system, and now em- 
ployed with great success in India. Ly this 
arrangement, a train leaving station A for sta- 
tion B itself puts the outdoor signal at Afto 
danger, and this signal remains unalterable by 
either signalman of himself, until the arrival of 
the train has been signalled from B to A, and 
“line clear” has again been asked for and 
obtained. Models of the Preece system, as 
worked on the London and South-Western 
Railway, the Sykes’ combined lock and block 
system, as used on the Metropolitan District, 
and other railways, and Harper’s interlocking 
instruments, as employed by the London, 
Brighton, and South Coast, and other Railways, 
are also exhibited. This company likewise 
shows the Saxby and Farmer Union of Lock 
and Block Signalling, and many other things, 
including Perry and Houghton’s alarm for 
tunnels, together with alarm-bells for gate- 
houses or level crossings. The electric fog 
and night signal of Mr. E. A. Sullivan is 
worthy of note. By this the wheel-tire of a 
passing train is made to press down a lever 
and sound a gong, but the gong can only be 
int i 
WT 
Johnson and Phillips’ Insulator. 
damaged, the telephone will often read a message when 
no other instruments will. Experiments at Aldershot, 
and recent experiences in Caffraria, have proved that a 
telephonic message can be received, though the wire is 
cut and lying on the ground. As an aid to military tele- 
graphy in a difficult country possessing a brilliant sun, 
the War Office also exhibit a Mance heliograph, or ad- 
justible mirror, for flashing a beam of light in signals, 
according to the Morse telegraphic code. The great 
advantage of this apparatus is that there is no wire which 
can be cut by the enemy, and little or no delay in erecting 
a sending-station. In the recent campaigns of Afghan- 
istan and Zululand it has proved of great service to the 
army, and messages have been flashed over distances 
varying from forty to sixty miles. 
Railway signalling from its earliest infancy is admirably 
sounded when the signalman liberates the 
lever by electromagnetism. In King’s Electric 
Railway Signal (exhibited by the Electric Rail- 
way Signalling Company of Stone Cross, N otts), 
there are signal posis placed at intervals along 
the line, and the train passing the first of 
these puts the signal, by mechanical means, 
at danger, while at the same time it signals 
forward by means of electricity to any distant 
junction. On passing the next post, it puts 
the signal at danger, and sets the post just 
past at line clear. At junctions the signals are 
connected with the points, which, when opened, 
show danger to the driver coming on the main 
line, and clear to the branch, remaining so 
until the points are closed. 
The English firm of Siemens Brothers, 
Charlton, exhibit a number of portable field 
outpost telegraphs, with sounders and inkers, 
such as are used in the German army. 
Jointers’ tools, A B C instruments, and other 
ordinary telegraphic apparatus, is also displayed, includ- 
ing specimens of their compound telegraph wire, made 
by covering steel wire with a skin of copper, to increase 
the electric conductivity and non-rusting qualities. Sie- 
mens’ telegraph poles made of wrought-iron tubes inserted 
into cast-iron tubular bases, are also exhibited, together 
with Le Grand and Sutcliffe’s base pile for sinking into 
the ground, to form a root for the pole. The great weight 
of this pole is, however, against it, for use abroad, where, 
owing to the ravages of the white ant, iron poles are pre- 
ferable to wooden ones. Weight is an important item 
when transport has to be considered in a new country, 
and hence the lighter pole of Mr. J. Muirhead (as exhi- 
bited by Messrs, Latimer, Clark, Muirhead, and Co.) has 
advantages in this respect. It consists of a light iron 
tube, strengthened below bya steel lining, and inserted 
