UTILIZATION" OF AMERICAN FLAX STEAW. 



11 



suits of one series of tests on a lime-cooked flax-straw paper are 

 here given (Table V). The wet sheets were placed on a cloth- 

 covered iron cylinder heated by steam to 103° C. and held down by 

 placing on top a cloth which was maintained at a definite tension. 

 The sheets shrank more and cockled more under a light tension than 

 under an increased tension. The physical tests were made at 80° C. 

 and 65 per cent relative humidity (fig. 3). 



Table V.- 



-Effect on the physical constants of paper dried under different 

 tensions. 



Tension of cloth. 



Breaking 



length 



of sheet 



(meters). 



Folding 

 factor of 

 sheet, 

 ream 25 

 by 40 by 

 500: 



550 grams . . 

 1,245 grams 

 2,155 grams 

 3,240 grams 

 3,700 grams 



3,165 

 3,420 

 3,810 

 4, 150 

 3,960 



0. 00312 

 .0040r 

 .00487 

 . 00571 

 . 00405 



From Table V it appears that within certain limits the strength 

 and folding quality of a sheet depend to a considerable degree upon 

 the method of drying. 



Bleaches were made with from 12 to 25 per cent of burned lime, 

 calculated on the bone-dry weight of the straw used, employing 

 temperatures from 135° to 170° C. and treating at the definite tem- 

 perature from 6 to 10 hours. 



The most thorough reduction and generally satisfactory results 

 were obtained with 11 per cent of lime acting for 10 hours at 170° C, 

 or the equivalent of 100 pounds steam pressure. The yield of total 

 fiber obtained did not vary much with the different bleaching condi- 

 tions, ranging from 60 to 68 per cent of the bone-dry weight of the 

 original straw employed. Determinations of the yield of washed 

 or separated fiber on the satisfactory bleaches gave an average of 32 

 per cent of the bone-dry Aveight of straw employed. 



MILL TESTS ON THE MANUFACTURE OF WRAPPING PAPER. 



Tests of wrapping paper from flax straw were made at Cumber- 

 land Mills. Me. Semicommercial machines were used, and most of 

 the work was performed by the regular mill employees. 



The straw used in these tests was raised in the vicinity of Fargo, 

 X. Dak., being the same as that used in the laboratory tests. It was 

 first sieved on a l!-mesh screen, in order to remove the loose chaff 

 composed of dirt, seeds, and empty seed capsules, which amounted 

 in total to 24.5 per cent of the original straw. 



