A Decennial Record 33 



and individuals outside of the laboratory, as well as for routine identi- 

 fication within the organization. 



/// the Use of Wood for Pulp and Paper 



One of the most comprehensive investigations completed by the 

 laboratory is the one on the grinding of wood for mechanical pulp, 

 which was conducted in a full size experimental ground-wood mill 

 especially constructed for the pin-pose at Wausau, Wisconsin. 



This study brought out the fundamental principles underlying 

 the grinding process and the effect of certain variables such as press- 

 ure, speed and quality of grinding surface upon the quality and 

 amount of pulp. The effect of preliminary steaming of the wood upon 

 the pulp was determined for a number of species, and the suitability 

 for mechanical pulp of a large number of American woods was deter- 

 mined. In fact, experiments were carried out on all species which 

 seemed to have any possibilities whatever; it being the intention to 

 make the study so nearly complete that no further work would have 

 to be done upon grinding for many years to come. 



Studies of similar breadth and scope have been under way for 

 many years in the production of chemical pulps from American woods. 

 Two principal objects liave })een aimed at, viz., to determine the funda- 

 mental cooking or pulping conditions underlying each of the three 

 principal chemical processes (sulphite, sulphate and soda), and to 

 <letermine the suitability of the individual species for the production 

 of pulp by the process or processes to which it is adapted. These 

 studies were not quite completed when war activities made it necessary 

 to a])andon them for the time being. They hnve since, however, been 

 finished and the results made available. 



Most paper is bought and sold upon specification, and the speci- 

 fication usually has some provision concerning the ])hysical properties. 

 ^Methods of determining these properties have })een very unsatisfac- 

 tory, however, and knowledge concerning the subject lacking. A 

 special testing room in which the atmospheric conditions can be kept 

 constant, has been constructed and series of tests made to develop the 

 inter-relationship among the various physical properties and to im- 

 ])rove methods of test. The effect of atmospheric moisture u])on the 

 strength of paper has been determined, and several new methods of 

 test ])erfectcd. 



