SCIENCE IN THE INDUSTRIAL WORLD 



and made the paper non-absorbent. This was known as 

 "sizing" and the solution used was called the "size." 

 The paper so treated was then dried, and if an espe- 

 cially smooth surface were required, was rolled between 

 metal rollers. 



This process of making paper is all but obsolete at 

 the present time, although a few hand-paper mills are 

 still in existence. English banknotes are still printed 

 on hand-made paper; but the American "greenback" 

 is made by machinery. The essentials of the processes 

 of hand-making and machine-making, however, are 

 practically identical, the difference being largely one of 

 method of application. Working under the old method, 

 it took three men a day to mold and finish four thousand 

 small sheets of paper, the process from start to finish 

 requiring about three months. By modern methods, 

 as we shall see, a forest tree, standing in its full vigor 

 to-day, can be marketed as paper to-morrow. 



MODERN RAG-PAPER 



The discovery that wood pulp could be utilized for 

 the manufacture of paper had a revolutionary effect 

 upon paper-making machinery and paper-making meth- 

 ods for certain kinds of paper. But no means have 

 been found, as yet, to produce the finer grades of paper 

 from wood pulp, or from anything else, save the time- 

 honored but plebeian rag. Indeed the rag industry is 

 almost as important to-day perhaps quite as important 

 as it was when rags were the only substance used 

 for paper-making. Thus we have the curious paradox 



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