His system consisted of a series of towers, each within line of sight of others, each supporting a wooden mast with two crossarms on pivots that could be placed in various positions.

The operator in a tower moved the arms to a sequence of positions, spelling out text messages in semaphore code.

His brother, Abraham, wrote "Reading this book greatly inspired him, and gave him a taste for the physical sciences.

[2] He and his four unemployed brothers decided to develop a practical system of semaphore relay stations, a task proposed in antiquity, yet never realized.

With his help, the Assembly supported a proposal to build a relay line from Paris to Lille (fifteen stations, about 120 miles), to carry dispatches from the war.

The Chappe brothers determined by experiment that the angles of a rod were easier to see than the presence or absence of panels.

[4] However, the Army preferred to use the word telegraph ("far writer"), which was coined by French statesman André François Miot de Mélito.

In 1824 Ignace Chappe attempted to increase interest in using the semaphore line for commercial messages, such as commodity prices; however, the business community resisted.

[12] A bronze sculpture of him was erected at the crossing of Rue du Bac and Boulevard Raspail in Paris.