Military telephone. Historical artwork of French soldiers using a Berthon telephone at the end of the 19th century. Berthon invented a microphone, known as the Berthon system, which improved the quality of the telephone, which had been invented in 1876. The apparatus shown here involves the unwinding of the telephone wire carried on the back of one of the soldiers (right). The correct functioning of the telephone requires the system to be electrically earthed using the pointed metal stick at lower right. Systems like this allowed better communication by French armies. Artwork from A Travers l'Electricite (G. Dary, Paris, 1900).