CHAPTEK II. 
ACOUSTIC TELEGRAPHY. 
Ancient system—Speaking Tubes—String Telegraph-Telephones—Telephone 
Companies. 
The historian Diodorus relates that a king of Persia 
communicated between Susa and Athens by the voices of the 
sentinels he had placed from distance to distance. The in¬ 
telligence was conveyed in one day over a space of thirty days’ 
march. 
Kircher in 1550, and Schwenter in 1636, wrote treatises on 
auricular signs, and proposed to translate the letters of the 
alphabet into musical notes. 
Bernouilli, in his “ Travels,” mentions that he saw at Berlin 
an instrument formed of five bells, which could express all the 
letters of the alphabet. 
It is said also that Alexander the Great discovered a mode 
of making himself heard by his whole army, at a distance of 
four leagues, by means of a speaking trumpet (tula stentoro - 
phonica). A representation of this instrument is preserved in 
the Vatican. 
Morland invented speaking-trumpets which gave great in¬ 
tensity to the voice. The king of England was, in 1670, 
presented with one of them, which enabled words pronounced 
a mile and a half off, to be audible even against the wind. 
Two or three of these trumpets were so far improved by 
Morland, that the Warden of Deal wrote to the First Lord of 
the Admiralty that a conversation could be carried on with 
vessels at a distance of three miles from the shore. Morland 
has left only imperfect descriptions of his speaking trumpets, 
but he showed that the tubes must be gradually enlarged 
towards their outer extremity, in order to reinforce the sound. 
In 1782, Dom Gantey made some experiments on the pro- 
