From rags to riches
The increasing demands for more paper during the late eighteenth and early nineteenth centuries led to shortages of the rags needed to produce the paper. Part of the problem was that no satisfactory method of bleaching pulp had yet been devised, and so only white rags could be used to produce white paper. Chlorine bleaching was being used by the end of the eighteenth century, but excessive use produced papers that were of poor quality and deteriorated quickly.
The potential of wood as a source of fibre for paper had been noted, in France, by Reaumur as early as 1719 from his observations of wasps, nature’s papermakers. Little was done to follow up his work until Jacob Christian Schäffer of Regensburg published the results of his experiments in using other materials, such as sawdust, rye straw, moss and spruce wood in 1765. In 1800 Matthias Koops, working in Bermondsey, also published his work on rag substitutes. This book included five leaves of paper made entirely from wood but without a description of how he achieved it. Finally in 1844 Charles Fenerty, in Halifax, Nova Scotia, demonstrated that ‘chafed’ wood could be used for paper manufacture and, in Germany, Keller patented a wood-pulp grinding machine making the production of Mechanical wood-pulp for newspapers a practical reality.
However, mechanically ground wood-pulp was not ideal for producing fine papers so the search continued for a better means of pulping wood. The first practical alternative, the Soda Process, was developed by Burgess and Watt in 1851 working at Frogmore Mill using caustic soda to chemically pulp the wood fibres. But, without any large forest interests in the UK, little financial support was forthcoming and Burgess went to America to secure his patent in 1854. The first mill to use this process was built near Philadelphia and began operations in 1855 under the direction of Burgess himself, who served as manager of the mill for nearly forty years.
An improved chemical wood pulping process, the Sulfite process, based on sulforous acid was invented by Benjamin Tilghman around 1868 and turned into a practical system first by Fry and Ekman in1870, improved upon again by Mitscherlich in 1876 and again by Ritter and Kellner in 1880. This process speeded up the ‘cooking’ time for pulp production significantly. The final commonly used chemical process for the preparation of fibres from wood was developed by Dahl in Germany in 1883. The Sulphate process is similar in many ways to the soda process, and its development was spurred by the desire to replace the unavoidable loss of soda with some material cheaper than soda ash.