456 



ELEMENTARY CHEMICAL MICROSCOPY 



Pyroxylin or Collodion Silk. (Denitrated Nitro-Cellulose.) Obtained by 

 nitrating cellulose, dissolving in ether-alcohol, filtering and either spinning into 

 filaments or forcing the collodion into water through fine nozzles. The filaments 

 are then denitrated by a suitable compound such as ammonium sulphide. 



Under the microscope the laboratory sample will be found to consist of structure- 

 less transparent flattened filaments, thicker at the edges than at the center. Longi- 

 tudinal striations when present are so faint as to be practically invisible. Edges, 

 straight and smooth. In cross-section the filaments are very irregular in outline, 

 the majority, however, are more or less dumb-bell-like or dumb-bell-like flattened 

 on one side. The filaments polarize strongly and when viewed edgewise give 

 high polarization colors. 



VI. COMMON PAPER FIBERS. 



Papers may be classified as follows: 



A. Textile fiber. . 

 papers. . . . 



a. Manufactured 

 waste. . 



b. Raw waste 



rags, sails, etc. 

 sacks 



rope waste 

 waste paper 



flax tow 

 jute butts 

 manila 

 hemp tow 

 (silk) 



B. Bast fiber papers. 



Linen (including ramie, china grass, etc.) 

 Paper Mulberry (Broussonetia papyri/era) 

 Adansonia (Adansonia digitata) 

 Mitsumata (Edgeworthia papyri/era). 



U. Palm fiber papers 

 Palmetto 

 Yucca 

 Coconut, etc. 



D. Grass and Bamboo fiber papers 



Straw (rye, oats, barley, wheat, rice, etc.) 



Maize 



Esparto (alfa grass = Stipa tenacissima) 



Bamboo 



Sugar cane, sorghum. 



E. Wood fiber papers 



Coniferous woods. . . . 



Non-coniferous woods. 



spruces 

 firs 



pines 

 hemlock 



f poplar 

 < bass wood 

 birch 



etc., etc. 



etc., etc. 



