16 



BULLETIl^ 404^ U. S. DEPARTMENT OF AGRICULTURE. 



located in the bottom of a circulating trough and the other set on the 

 periphery of a roll revolving just above the former set of knives. It 

 is during this operation that the loading and sizing agents are incor- 

 porated and the whole furnish is tinted either to produce a satisfac- 

 tory white or the desired color. 



The term "paper making/' as used in this publication, means the 

 operation of forming the finished sheet of paper from stock which has 

 been furnished and prepared in the beater. In these tests a 30-inch 

 Fourdrinier machine of regular construction was used, a machine 

 which often is used for the production of paper for filling regular com- 

 mercial orders. The machine is designed to cause the water suspen- 

 sion of fibers to flow on to a traveling wire cloth, whereby the water 

 drains away. More water is removed by passing the wet sheet through 

 a series of press rolls, after which the sheet is dried on steam-heated 

 drums and passed through polished iron rolls, which impart a finish 

 to the sheet. A Jordan refining machine was employed in conjunction 

 with the machine to improve further the quality of the fiber, and a 

 pulp screen was used in order to remove coarse and extraneous mate- 

 rials from the fiber. 



DESCRIPTION OF TESTS. 



The nature of each complete paper test and the dependence of 

 each operation. on the others were such that it does not seem advisable 

 to submit the results of the seven tests in tabular form. The numer- 

 ous cooks, however, which furnished the pulp for the paper tests are 

 presented in Table I in all essential detail. 



Table I. — Data on cooking hemp hurds. 



Cook No. 









Cooking. 



Caustic 



soda used 



(percentage 



of bone-dry 



Strength of 



caustic soda 



(grams per 



liter). 



Causticity 

 of soda 

 solution. 







Time 



Tempera- 



liurds). 





(hours). 



ture (°C.) 



20.6 



100 



75.3 



3 



166 



21 



100 



75.3 



3 



166 



21.6 



100 



75.3 



3 



166 



20.3 



100 



75.3 



3 



166 



21.9 



100 



82.5 



4 



166 



24.4 



100 



82.5 



4 



166 



24.2 



100 



84.3 



4 



166 



25 



100 



84.3 



4 



170 



25 



100 



84.3 



5 



170 



27.8 



107.5 



84.3 



4 



166 



26.7 



107 



84.4 



5 



170 



26 



107 



84.4 



5 



170 



27.3 



107 



84.4 



5 



170 



27.1 



107 



84.4 



6 



170 



27.2 



107 



84.4 



6 



170 



28.3 



116.5 



85.5 



5 



170 



29.1 



113.1 



84.9 



5 



170 



29.1 



109 



83.9 



5 



170 



29.4 



109 



83.9 



5 



170 



30 



109.5 



84.9 



5 



170 



29.6 



109.5 



84.9 



5 



170 



29.6 



107 



84.8 



5 



170 



29.4 



107.5 



84.2 



5 



170 



29.3 



107.5 



84.2 



5 



170 



Yield of 

 bone-dry 

 fiber (per- 

 centage of 

 bone-dry 

 unsieved 



hurds). 



293 

 294 

 295 

 296 

 301 

 302, 

 303 

 304 

 305 

 306 

 307 

 308 

 309 

 310 

 311 

 312 

 313 

 314 

 315 

 316 

 317 

 318 

 319 

 320 



(1) 



44.1 

 39.5 

 39.4 

 36.5 

 38.1 



37.3 



37.0 

 36.8 

 35.9 



35.2 



34.9 

 37.2 

 37.0 

 37.7 



35.4 



1 Stock not used; dirty. 



