Mary Pears, Francis's eldest daughter, and was appointed to run the administration in London. During the nineteenth century, Pears built a large market for its soap in the United States. Following Barratt's death in April 1914, Lever Brothers took a major shareholding in A & F Pears. The takeover process was completed in 1920 and marketing and other secondary functions moved to Port Sunlight in north-west England, but production continued at Isleworth. In the mid to late 1950s, each batch of soap, about 12 a day, was tested to ensure the absence of excess alkali or free fatty acid. Production moved to Port Sunlight in the 1960s, when Unilever, successor to Lever Brothers, set up a cosmetic development laboratory on the Isleworth site. A major fire at the site completely destroyed the original factory. Pears soap is now made in India by Hindustan Unilever, a company in which Unilever now has a 67 percent share. Manufacture Pears soap was made using a process entirely different from that for other soaps. A mixture of tallow and other fats was saponified by an alkali. Clearly, this is currently caustic soda (sodium hydroxide), since the ingredients list shows sodium salts of fatty acids, but a chemist reports that in the 1960s, caustic potash (potassium hydroxide) was used. It has not been possible to determine what was used in the early days of the product, as the writings of Francis Pears mention only alkali in industrial methylated spirits. After saponification was completed, the resulting glycerol was left in the batch. Batches were made not in huge pans, but in small kettle-like vessels. As soon as the translucent amber liquid had cooled enough to solidify, it was extruded into opaque oval bars that were cut into bath- or toilet-weight tablets, ready for beginning their long spell in the drying rooms (ovens). The hot liquid soap fresh from the vessel had a total fatty matter (TFM) of 45% compared with the TFMs of 70–80% usual in soaps made by the conventional method. The TFM increased considerably as the alcohol content fell during drying. The concave shape of the soap is formed by shrinkage while the soap is drying, and is not due to deliberate moulding. The entire Pears plant was a small almost self-contained annexe at the rear of the administration block. It was run by a handful of staff, who not only had experience of