The Arab doctors, perfumers and metallurgists made their greatest contribution in chemistry. This was mainly due to the fact that Arab scholars, unlike their predecessors in Greece, never hesitated to take part in laboratory practices in handling drugs, salts and precious metals. The Arabs continued the Egyptian and Babylonian traditions, and learnt extensively from the Indian and the Chinese sources. To these they added their own rich contributions, giving rise to the first statements of scientific chemistry. Arab chemists greatly improved the earlier distillation apparatus and used it for large scale production of perfume. They also undertook large scale production of soda, alum, copperas (iron sulphate), nitre and other salts which could be exported and used particularly in textile industry. While they perfected new techniques, they were not satisfied till they were able to get at the bottom of the reactions which made these techniques possible. Arab chemists stipulated the positive and negative naturc of two reacting constituents. This was the first time that chemical transformation was approached rationally, to lay the basisly modem chemistry.