Charles Barbier used a similar system, because Napoleon wanted a code that soldiers could use to exchange messages silently and without light at night. Barbier called it night writing. Night writing uses two columns of six dots. It uses phonemes (separate sounds), not letters. Barbier's system was too hard for soldiers to learn, and the military did not use it. From the year 1821, he started to test his system in the school Haüy had founded. There it became very successful. Even though the system was difficult to learn, it did help the blind to read better than earlier systems. Barbier had understood that it was better to use a system that used dots over one that used lines.