cidedly whiter in color. The slow penetration in 

 the case of the larger chips pointed to the diffi- 

 culties which would be encountered in using this 

 type of treatment on chips of the normal pulping 

 size. Ether, gasoline, ligroin and petroleum ether 

 all yielded clear, bright yellow rosin, showing 

 the excellent quality of the rosin as it existed in 

 the wood. Ethyl alcohol, methyl alcohol, and 

 acetone showed slightly greater extractive powers, 

 the rosin, however, being deeper in color and some- 

 what cloudy. Ether is the most satisfactory 

 solvent for rosin, the solubility being 38-39 per 

 cent at 23C. (H. A. Loos, "A Study on Colophony 

 Rosin/' Columbia University, 1900), and was used 

 in subsequent quantitative determinations. 



Extraction with alkalis is different in principle. 

 The rosin is saponified and dissolved as a soap, 

 while the turpentine is liberated from the rosin 

 without itself dissolving in the alkaline solution. 

 An important consideration is that the alkali 

 causes partial decomposition of the wood itself. 

 The lignone group of the wood is converted by 

 alkaline solutions at elevated temperatures into 

 soluble derivatives, which are acid in nature but of 

 somewhat uncertain composition (Cross and Bevan, 

 "Wood Pulp and its Uses," p. 62). This prin- 

 ciple is carried to the limit in ordinary pulping 

 operations, where the final pulp consists of cellu- 

 lose practically free from lignin. Heating the wood 

 in dilute caustic solutions at the moderate tem- 

 peratures necessary for rosin extraction represents 

 the initial stage of lignin decomposition. The 

 dissolved bodies from this source consist mainly 

 of organic acids of the type of saccharinic and iso- 

 saccharinic acids, as well as those of a lower order, 

 such as formic and acetic acids. In addition, there 

 are dissolved those water-soluble bodies and lower 

 carbohydrates, which exist in the wood to the ex- 

 tent of 5-10 per cent chiefly pentosans and hexo- 

 sans, such* as the glucosides of xylose, mannose, 

 etc. (see Klason and Segerfelt, Papierfabrikant, 9, 

 1911, pp. 1093-9). For convenience, the decom- 

 position products of the lignin of the wood will 

 be designated as "humus" throughout the dis- 

 cussion. 



16 



