HEMP HUEDS AS PAPEE-MAKHSTG MATERIAL. 17 



Discussion of the various cooks will be given in connection with 

 the descriptions of those paper tests in which the stocks from the cooks 

 were used, since a stock and its cooking condition can be judged ade- 

 quately only after it has been put through the various processes and 

 into the finished sheet of paper. 



The first test consisted in making four separate cooks, Nos. 293, 294, 

 295, and 296, of approximately 300 pounds each, dividing the total 

 stock into two parts and making two separate paper tests. The 

 lu'st test was made primarily in order to learn some of the qualities 

 and characteristics of the stock and to get the machinery equipment 

 adjusted properly. The yield of fiber was not determined in this 

 prehminary test, since the knowledge of it was not essential at this 

 stage of the work. The cooked stock which was emptied into the 

 drainer to be washed free from black liquor was composed largely of 

 whole pieces of hurds, but only slight pressure between the fingers 

 was required to crush the pieces. In the case of wood, this condition 

 ordinarily would indicate undercooking, but might not in the case of 

 hurds. Further observation on the action of the cooked stock during 

 subsequent processes was necessary in order to judge of its quality or 

 the suitability of the cooking conditions. The total cooked stock, 

 about 500 pounds, was divided into two portions of 200 and 300 

 pounds, respectively, and work was continued on them separately. 

 The 200-pound test, designated as run No, 135, was put into a 350- 

 jDOund washing engine, washed one hour, and given a total light brush 

 of 2 J hours. The washing removed a great amount of dirt, but the 

 engine did not reduce the hurd stock as much as was desired. After 

 heating the stock in the beater to 40° C, it was bleached with bleach- 

 ing-powder solution, 94 gallons at 0.418 pound bleach per gallon, 

 equivalent to 19.7 per cent of the fiber. This percentage of bleach is 

 regarded as too high for stock intended for book-paper manufacture, 

 and subsequent cooks therefore were given harder treatment in order 

 to reduce this figure. After draining and washing free from bleach 

 residues, the stock was furnished in the beater with 13 per cent of 

 clay, 1 per cent of resin size, and 2.5 per cent of alum, was tinted 

 blue, given one hour's light brush, and pumped to the stock chest. 

 When running it on the paper machine, the Jordan refiner seemed 

 to have little effect in reducing shives of undertreated wood, which 

 indicated further the necessity of harder cooking. The furnish acted 

 well on the paper machine at 70 feet per minute, but appeared some- 

 what too "free " on the wire. The paper produced from this test is of 

 very low quality, due to the improper preparation of the stock, lack 

 of sufficient bleach, the use of too small an amount of blue tinting, and 

 the presence of an excessive amount of dirt, sand, anfl shives. The 

 excessive amount of dirt and sand suggested the sieving of the hurds 

 before cooking, and this was performed in all subsequent cooks. 



