82 
THE TELEGRAPH . 
(Ersted, who came to Paris in 1802 and 1803, and again in 
1813, was on each occasion in communication with Aldini. 
Izarn’s manual, printed in 1805, appears to exactly reproduce 
the statement in Aldini’s book printed in 1804. The following 
is the passage: 
“ According to the observations of Romagnesi, the physicist 
of Trent, an already magnetized needle subjected to the 
galvanic current undergoes a deviation/’ This is precisely 
what everyone has, since 1820, been accustomed to call 
(Ersted’s discovery; Romagnesi certainly deserves the credit 
of having first opened out the region which has since yielded 
so much to other explorers. 
Aldini’s book also mentions the chemist Joseph Mojon of 
Genoa as having observed, before the year 1804, that unmag¬ 
netized needles placed near a galvanic current acquire a kind 
of polarity. Izarn repeats this in his “ Manuel du Galvanism 
many copies of which must still exist in France, as the book 
was ordered to be placed in the libraries of all the high- 
schools. 
Ampere was the first to suggest that the movements of the 
magnetic needle produced in this way might be useful in 
telegraphy ; but neither he nor any other person attempted at 
that period to arrange apparatus for the purpose. 
It was Baron Schilling who constructed at St. Petersburg 
the first electro-magnetic telegraph. His connection with 
Soemmering had made him passionately attached to the idea 
of constructing a galvanic telegraph. His first apparatus con¬ 
sisted of a magnetic needle suspended horizontally by a filament 
of silk within one of Schweiger’s multipliers. Under the 
needle was a paper disc painted in two colours so that the 
movements of the needle might be the better discerned. In 
order to give steadiness to the needle and prevent oscillations, 
there w T as attached to the needle below its centre a small 
piece of platinum which dipped into a vessel of mercury. For 
some time Schilling made use of five needles ; but by degrees 
he simplified his apparatus, and at length he was able to signal 
with a single needle and a single multiplier, producing all 
signals required for letters and figures by different combinations 
of movements in two directions. 
In September of the same year, Schilling exhibited his 
