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: 
rags, sails, etc. 
sacks 
rope waste 
waste paper 
a. Manufactured 
waste. 
A. — Textile fiber, 
flax tow 
jute butts 
manila 
papers. 
b. Raw waste 
hemp tow 
(silk) 
B. — Bast fiber papers. 
Linen (including ramie, china grass, etc.) 
Paper Mulberry {Broussonetia papyrifera) 
Adansonia (Adansonia digitata) 
Mitsumata {Edgeworthia papyrifera). 
L. — Palm fiber papers 
Palmetto 
Yucca 
Coconut, etc. 
D. — Grass and Bamboo fiber papers 
Straw (rye, oats, barley, wheat, rice, etc.) 
Maize 
Esparto (alfa grass = Shpa tenacissima) 
Bamboo 
Sugar cane, sorghum. 
E. — Wood fiber papers 
Coniferous woods 
spruces 
firs 
pines 
hemlock 
etc., etc. 
Non-coniferous woods 
