USES OF WOOD PULP. 



For a number of years the Mitscherlitch brothers maintained their German patents 

 and received royalties on all pulp manufactured in this country by their methods, 

 so that the price was maintained at about $10 per 100 kilograms (220 pounds). But, 

 after a long and determined litigation, the German courts set aside the Mitscherlich 

 claims, and from that time the number of factories increased to 63, of which 21 ex- 

 port part or all of their product, 21 sell only to German consumers, and 21 consume 

 their own pulp in the manufacture of paper and cellulose articles. This abolition 

 of the inventors' royalties and the consequent increased number of factories so 

 sharpened competition that the price of air-dried chemical pulp has declined to 

 about $5.25 per 100 kilograms, and, if the statement of manufacturers may be 

 credited, there is now comparatively little profit in the business. Consumers have 

 become very fastidious and exacting in respect to quality, only the whitest and purest 

 grades having now any chance in the competition for export to France or England. 

 The scarcity of water power compels the use of steam power by most of the fac- 

 tories, and the important advance which has occurred in the cost of German coal 

 since 1888 has borne heavily on the pulp makers, handicapped as they already were 

 by costly wood, labor, and freights. 



But the steadily increasing consumption of paper and paper goods, particularly 

 in the United States, must in the end transfer a large portion of the pulp industry 

 to our own country; and, in view of the frequent inquiries which have been received 

 at this office during the past year for technical information on the German methods 

 of cellulose manufacture, a succinct account of the Mitscherlich process is herewith 

 submitted. 



The underlying principle upon which this process is based is the fact, well known 

 in chemistry, that the resinous matrix or incrusting material which surrounds and 

 holds together the individual fibers of wood is soluble and produces a chemical 

 reaction with certain aqueous solutions of bisulphites, notably that of the bisulphite 

 of lime. The problem was to apply the bisulphite under conditions which would 

 completely and quickly eliminate the incrusting substance without unnecessarily 

 weakening the fiber, and for this purpose it was found best to apply the solution at 

 a high but carefully governed temperature and under a mechanical pressure that 

 would force the chemical solution into every pore of the woody structure and en- 

 able the loosened and dissolved matrix to be removed by washing with water. 

 The more intense the heat and the stronger the chemical solution employed the 

 greater the injury to the fiber, and in perfecting his method Dr. Mitscherlich was 

 careful to ascertain the exact minimum degree of both heat and pressure that would 

 best promote the desired result. His process is, in its integrity, somewhat slower 

 than other modifications of the sulphite system, but each manufacturer regulates 

 these conditions to fit the nature of the wood employed, the quality of product 

 desired, and the relative capacities of boiling and finishing apparatus. The Mit- 

 scherlich process, as practiced at Okriftel, Aschaffenburg, and v other points in the 

 district of Frankfort, may be described as follows: 



The wood used is pine, mainly of the variety known in Germany as "Tannen- 

 holz," which grows straight and slender in the densely planted forests, the supply for 

 this region coming from the Black Forest and the Odenwald. The trees, when cut 

 in the latter forest, are from 8 to 12 inches in diameter and have few or no branches 

 except near the top. They are carefully selected, felled, and cut into lengths 

 of about 8 feet, the bark shaved off, and knots and other blemishes removed by 

 hewing or boring. The selection and preparation of the timber for pulp making 

 is a most important part of the business, the workmen assigned to that duty being 

 among the most intelligent and liberally paid of all occupied in the manufacture. 

 Experienced German pulp makers ascribe much of the difficulty encountered by 

 their American competitors in making high-grade cellulose to the lack of sufficient 



