The development of the synthetic jewel industry by Verneuil-method in France, Switzerland, Germany and also in Japan and in America is reviewed chronologically, from pre-Verneuil stage. Especially many improvements in Verneuil-method achived in Germany during the period of 1900-1935 are surveyed in some details. In Japan, the present author initiated researchs on Verneuil-method in 1935, at the Research Laboratory of Tokyo Electric Co. (present Tokyo-Shibaura Electric Co.) and successfully established the boule-manufacturing factory in 1940. Several factories have been established since then, some were abandoned. A brief survey on Japanes jewel industries is made. The jewel-manufacturing factory in America was established in 1940 and it is reported that the factories using Verneuil-method have almost stopped their operation. The Verneuil-plants in other countries are still active and continue their activities.
