20 BULLETIN 309, U. S. DEPARTMENT OF AGRICULTURE. 



This evidence was considered sufficiently complete with regard to the oxycellulose 

 question. The behavior of Epicampes pulp with the usual solvents of cellulose was 

 tried, with results as follows: 



(a) Schweitzer's reagent dissolved all but the merest faint trace of the fiber. 



(6) Concentrated sulphuric acid dissolved the fiber quite rapidly and completely, 

 with a very faint darkening in color — not nearly so dark as straw celluloses usually 

 give with sulphuric acid. 



(c) Zinc chlorid in concentrated hydrochloric acid dissolved the fiber more slowly 

 than did sulphuric acid, but quite completely. 



(d) Zinc chlorid solution swelled the fiber, but dissolved it only slowly. 



The percentages of ash and moisture were also determined, ash being 2.2 per cent 

 and moisture 4.8 per cent. Both determinations are of minor importance, the ash 

 qualitatively and quantitatively being dependent on the previous treatment of the 

 pulp and the moisture on the atmospheric conditions. The fact that they were not 

 extraordinary had, however, to be determined. The moisture was within 0.2 per 

 cent of that of poplar pulp under the same atmospheric conditions, indicating again 

 the close chemical relationship that has been evident throughout in the comparison 

 of poplar and Epicampes pulps, as it is well known that different forms of cellulose 

 have widely differing hygroscopicity. It is, in fact, more closely related to poplar 

 pulp than it is to straw celluloses, like those of wheat or rye. These latter give from 

 12 to 14 per cent of furfural, for example, while Epicampes pulp gave a 10.8 per cent 

 average, poplar giving 10 per cent. The resistance of Epicampes cellulose to destruc- 

 tive agents in general is correspondingly higher than that of the usual straw celluloses. 



It was next intended to make a methoxyl determination on the Epicampes pulp, 

 but microscopic examination showed (1) lignified cells still present and (2) cells in 

 bundles that are usually completely separated by cooking, although only a very little 

 of either. A methoxyl determination would be unfair to the sample when thus under- 

 cooked, and so was not carried out. 



Direct determination of cellulose by any of the accepted methods is obviously use- 

 less here, (1) because the pulp has already been through processes for lignin removal 

 and (2) because the presence of oxycellulose renders impossible a determination of 

 cellulose accurate to 15 per cent, as it is always attacked much more than lignin by 

 the usual reagents. There is no existing accurate method for these conditions. 



Carbon and hydrogen determination by combustion would add, perhaps, a little 

 to the already present wealth of evidence of oxycellulose presence, but the relation 

 of furfural yield to carbon percentage is so well known that the carbon could be pre- 

 dicted to a fraction of a per cent. This determination, therefore, seemed needless 

 for the complete characterization of the Epicampes fiber. 



Hydralcellulose was tested for during the ' 'copper number' ' determinations, by 

 Schwalbe's method, and found absent. 



To sum up the net result of these determinations: Ejricampes macroura bleached 

 pulp is a natural oxycellulose closely related to poplar pulp in chemical properties 

 and considerably superior to the usual straw celluloses in power of resisting chemical 

 attack by destructive agencies. 



SEMICOMMERCIAL TESTS OF THE PULP. 



Having experimentally determined the cooking conditions and 

 found them to be reasonable and satisfactory and also having deter- 

 mined that the chemical nature of the pulp was satisfactory, the 

 work was continued on a semicommercial scale and was planned to 

 include the actual manufacture of paper. There is a tendency on 

 the part of many to discount the practical value of results obtained 



