I'lioroMicRocK.iriiy .ixd ir.i iixic.il MicKoscoi-y 



Fig. E. Paper fil)irs liy 97 X. \<ite the surface markings: the gradation 

 in cnlor and the aiipcarance i>f nmii<hiess possessed by some of the fillers. The 

 photograph was taken with a modern medimn-power apochromatic olijective. 



Microscopic examination of textile and paper fibers atTords a means of 

 iilcniification second to none. The fibers arc recogni/.cd by characteristics 

 pecuhar to each and by color reactions to different stains. Cotton, for example, 

 appears as a flat ribbon-like fiber twisted spirally; linen is round and shows 

 "joints" and cross markings. The specimen illustrated consisted mostly of linen 

 with a small proportion of cotton added. 



Fig. F. Electrical porcelain by p(darizrd light, magnification 100 X. 



The quality of the porcelain may be judged to a considerable degree by a 

 microscopic examination. The degree of vitrification is indicated by the round- 

 ing of the sharp corners on the quartz grains; whether or not the porcelain is 

 homogeneous may be determined by the uniformity in distribution of the un- 

 dissolved particles, and fissures, cracks, or voids are readily seen. All of these 

 factors influence the physical characteristics of the porcelain. 



