The converter invented by Henry Bessemer in Wales for the steel industry was adapted in copper production by Pierre Manhés in France after changing bottom blowing to side blowing. This new technology replaced the Welsh process for copper production which was based on the roast reaction. The application of this new technology to nickel sulfide necessitated the invention of the Top Blown Rotary Converter. A new furnace was further applied to the conversion of lead sulfide to replace the ancient roast reaction for lead sulfide.