The process of weighting silk has been greatly abused, as it is comparatively simple to adulterate it, without discovery, to such an extent that the properties of the fibre are seriously impaired. Weighted silk never has the strength or wearing quality of the unadulterated product. However, a certain amount of weighting—to restore a part of the degumming loss—is generally recognized as legitimate, although the percentage permissible is often a matter for discussion. Both skein and piece silk are dyed by being immersed in vats containing the hot dye solution. The silk is run over rollers which insure even coloration throughout. After dyeing it is dried, stretched on a tenter frame and then submitted to dry heat which sets the dye and adds luster to the silk. [Sidenote: _Printing_] Printing is also used for coloring and pattern effects in very much the same way as for cotton goods. After printing the goods are submitted to a dry steam heat which sets the colors. [Sidenote: _Finishing_] Beyond dyeing or printing, silk goods require very little finishing other than calendaring by passing through rollers. Some types of fabric require softening and others, hardening—accomplished in a variety of ways too numerous to describe. Many of these are secret processes perfected and patented by individual companies. A multitude of different effects can be obtained by these various treatments of the surface of the goods. CHAPTER VI ARTIFICIAL SILK 1. EARLY DEVELOPMENT [Sidenote: _Chardonnet_] The discovery of what is known as “artificial silk” is generally attributed to a Frenchman, Count Hilaire de Chardonnet, who after many years of research and experimentation, between 1840 and 1890, finally perfected a fibre that possessed the necessary qualities for practical weaving. He introduced his discovery to the public in 1891 at the Paris Exposition, and in addition to winning the “Grand Prix” was also made a knight of the Legion of Honor in recognition of his contribution to science and industry. [Sidenote: _Further Development_] Since that time others have contributed to the development of the new fibre and discovered other methods of production—all, however, based on the same general principle as the Chardonnet process. Despaisses and Panly, two Frenchmen, and Stearn, Cross and Bevan, Englishmen, are the outstanding names in this work. 2. VARIOUS PROCESSES [Sidenote: _Use of Cellulose_] All the processes that have met with any success are based on the use of cellulose in some form, as a foundation. The two sources that have proved most successful are wood-pulp and cotton and it may be said that the bulk of the artificial silk on the market comes from one or the other of these two raw materials. [Sidenote: _Chardonnet Process_] The Chardonnet process uses cotton as its base. It is first bleached, then by chemical treatment is changed to nitro-cellulose, which is dissolved in alcohol and ether and thus made ready for “spinning.”