18 BULLETIN 404^ U. S. DEPARTMENT OF AGRICULTUEE. 



The finish of the sheet is very poor, due to the fact that the calender 

 stack was composed of very light rolls which did not have a satisfac- 

 tory surface, yet the stack is known to be able to produce better finishes 

 if the proper stock is employed. 



Run No. 136 was made on the 300-pouiid portion of stock from 

 cooks Nos. 293, 294, 295, and 296, and in essentially the same manner 

 as run No. 135. The stock was washed one hour, but given a brush 

 of three hours, and this brush was harder than in run No. 135. 

 Bleach to the extent of 19.8 per cent of the fiber was used, assisted 

 by 1 pint of oil of vitriol, and the resulting color was an improvement 

 over that of run No. 135. After adding 13.5 per cent of clay and 

 sizing with 1.1 per cent of resin size, the furnish was given one-haK 

 hour's light brush, tinted, and run on the machine, which was set 

 at 70 feet per minute. This stock acted better on the wire and gave 

 no trouble on the machine, but it still seemed to be impossible to 

 reduce the wood shives by manipulation of the Jordan refiner. The 

 resulting sheet is an improvement over that produced by No. 135, 

 but is far from satisfactory. 



Run No. 138 was made from hurds which, as in all subsequent tests, 

 were sieved on a ll|-mesh wire screen until practically all the loose 

 dirt and sand was removed, which operation caused a loss averaging 

 3 per cent of the hurds. Stock from cooks Nos. 302 and 303 was 

 used for this run and the increased amount of caustic soda and the 

 increase in the time of cooking gave a stock of better appearance than 

 those of preceding tests. 



The stock, amomiting to 231 pounds dry weight, was washed and 

 at the same time given a light brush for one hour only, after which 

 it was bleached with 17 per cent of bleach without the addition of 

 acid. Since the preceding paper appeared somewhat weak and had 

 a low tearing quality, it was decided to use a furnish of 15.7 per cent 

 bleached sulphite and 84.3 per cent bleached hemp-hurd stock. 

 After loading with 13.1 per cent of clay and sizing with 1.1 per cent 

 of resin size, the furnish was given a medium brush for one hour, 

 tinted, and run on to the machine at 70 feet per minute. The stock 

 gave no trouble on the machine, but it was impossible to judge the 

 effect of the Jordan refiner, because through an oversight the machine 

 chest had not been cleaned since previous use on an unbleached 

 yucca material. It is believed, however, that sheet No. 138 shows 

 improvement in the preparation of the hurd pulp. 



Rim No. 139 was made from stock of cooks Nos. 304 and 305, 

 in which still more caustic soda was employed and the time and tem- 

 perature of cooking were increased, giving a yield of total fiber of 

 40.7 per cent of the sieved or 39.4 per cent of the misieved hurds. 

 The cooked stock still seemed to be undertreated, but it must be 

 remembered that in working with any new raw material it is impos- 



