ZACATON AS A PAPER-MAKING MATERIAL. 17 



the losses ran about 20 per cent, while with the more dilute they were from 8 to 10 

 per cent, with, as was noted, a large factor of possible error. The ordinary bleaching 

 practice would give results nearer the lower limit, if anything. 



The blow-pit stock from which the pith had not been separated did not bleach to a 

 good color, even on long treatment. The loss in weight in one case which was weighed 

 was 12.5 per cent, but the stock was not up to a pure white — rather a light cream color. 

 This was due partly to the depth of coloring of the cooked pith and its resistant nature. 

 The strongly resistant nature of the pith is seen by comparison of the results of dilute 

 alkali and acid treatment with their effect on the original straw. 



The loss on boiling the pith 1 hour with 1 per cent caustic soda was 18.5 per cent 

 in one case and 17.8 per cent in another. The straw lost 45 per cent under similar 

 treatment, and the pure bleached fiber 20 per cent. 



The loss on heating the pith 7 hours at 70° with 10 per cent nitric acid was 18.3 per 

 cent in one case and 17.9 per cent in another, while the straw lost 61 per cent and the 

 pure bleached fiber lost 10 per cent under the same treatment. The necessity of 

 removing the pith, even at the expense of some fiber, is apparent. There was quite a 

 iittle fiber in the sample of pith, as shown by shaking up a sample with an excess of 

 water, but no method of quantitatively separating the two has as yet suggested itself, 

 unless fractional levigation or filtration may succeed in some form later. Chemically, 

 there is not enough difference to effect even an approximate separation. 



3. Black liquor.— The black liquor resulted from cooking Epicampes straw in an 

 autoclave at 90 pounds for 7§ hours, using 23 per cent caustic on the straw weight, at 

 concentration of 23.9 grams per liter. It was investigated for specific gravity, per- 

 centage of dissolved solids, saccharine matter, nitrogenous matter, ash, and total 

 organic matter. 



The specific gravity of the liquor was 1.046. It had 9.9 per cent total solids dis- 

 solved by one determination, and 10 per cent according to a second. Of this, 2.89 

 per cent should be the original caustic soda (of course, somewhat altered by combi- 

 nation with silica, etc.). A determination of the ash of the evaporated residue cor- 

 roborated this; 6.2 per cent of the residue burned away in the blast, leaving 3.8 per 

 cent ash, the 6.2 per cent being, then, total organic matter. The amount of ash does 

 not by any means account for the silica of the straw, even assuming that half of it is 

 left in the finished paper. It is probable that much of it is loosened by the cook and 

 is washed away as a fine suspension. 



A Kjeldahl analysis of an evaporated residue showed 2.1 per cent "proteid," using 

 the usual factor in calculation from the ammonia found; that is, there was about 

 0.2 per cent proteid in the liquor before evaporation. 



The addition of mineral acid to the black liquor gave a voluminous precipitate, 

 consisting of acid cellulose, lignic acids, and some silicic acid. The amount of the 

 precipitate was 4.8 per cent of the black liquor, leaving, then, 1.4 per cent organic 

 matter in the filtrate. 



The filtrate was examined for sugars. In 100 c. c. of the filtrate only 33 milligrams 

 of sugar were present, calculated to dextrose. Probably the remainder in solution 

 was levulinic acid, humic acids, acid-soluble modifications of cellulose, and similar 

 products of the breaking down of the complex substances in the straw, but their 

 small quantity and lack of value after identification argued against the necessarily 

 long and laborious task of isolating them, even if they could be identified. 



Condruion. — The result of an investigation like the present one on substances of 

 this nun in- gi . e necessarily only u general impression rather than a summary of defi- 

 nite and precisely measurable constants. In general, it may be said that Epicampes 

 macroura gives a commercially practical yield of rather unusually high-grade paper 

 fiber, with no particular trouble to be expected except from pith and silica in the 

 procee of manufacture. 



