Glycerin soaps are soaps that contain glycerin, a component of fat or oil. The soap is recognizably different from other soaps because it is translucent. The process for making glycerin soaps was well known as of 1857 in the Western world.
Pears transparent soap is a brand of soap first produced and sold in 1789 by Andrew Pears at a factory just off Oxford Street in London, England. It was the world's first transparent soap. Under the stewardship of Thomas J. Barratt, A. & F. Pears Ltd. company initiated a number of innovations in sales and marketing. According to Unilever records, Pears Soap was the world's first registered brand and is therefore the world's oldest continuously existing brand.
1.^ a b Piesse, G. W. Septimus (1857), The Art of Perfumery And Methods of Obtaining the Odors of Plants, PHILADELPHIA: C. SHERMAN & SON, http://www.gutenberg.org/files/16378/16378-h/16378-h.htm