PART I. 
OPTICAL TELEGRAPHY—ACOUSTIC TELEGRAPHY- 
PNEUMATIC TELEGRAPHY. 
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CHAPTER I. 
OPTICAL TELEGRAPHY. 
System of the Ancients—Various Methods before Chappe’s Telegraph—Aerial 
Telegraph—Leseurre’s Heliograph—Mance’s Heliograph—Its application 
to the Service of the English Army in Afghanistan—System proposed by 
Sir William Thompson for distinguishing one Lighthouse from another. 
In his “ Art of Signals,” published at Hanau in 1795, Major 
Boucherceder states that the art of telegraphy dates from the 
building of the Tower of Babel in the year b.c. 2247. This 
structure, he thinks, must have had for its special purpose the 
establishment of a central point of communication between the 
different countries then inhabited by mankind. 
Scripture also relates that columns of fire and of smoke were 
used to lead the Israelites across the desert after their flight 
from Egypt. 
The idea of attaching a signification to the appearance of fires 
on heights is so natural that traces of it are found among 
various savage tribes in Africa. 
History and poetry have preserved certain traditions which 
prove that the art of telegraphy was used in heroic times. 
Hannibal erected watch-towers in Africa and in Spain in 
order to transmit phrases by signals. The Romans adopted 
this method, and wherever they extended their conquests, they 
established rapid communications which enabled them to main¬ 
tain their power over the conquered nations. Remains of these 
towers still exist in France. Those of Uzes, Bellegarde, Arles, 
