(11) Transparency is penetrability to light and is expressed as the 

 thickness of the paper through which a standard flame can be barely 

 distinguished. 



(12) Moisture and ash are expressed as percentage on the basis of 

 the air-dry paper. Loading as distinguished from the normal min- 

 eral content of the paper and that added in the sizing and coloring 

 can not be definitely determined, but may be approximated for dif- 

 ferent kinds of paper. At present no corrections will be made for the 

 loss on ignition of water of constitution or hydration present in 

 China clay or other loadings, but the practice of the Bureau may be 

 changed at any time on this point. 



(13) Absorptive power of blotting paper is shown by the height in 

 millimeters to which water will be drawn in ten minutes' time by a 

 strip of the paper 15 mm broad. 



QUALITATIVE TESTS. 



(1) Kind of sizing includes a statement as to whether rosin, animal 

 sizing, starch, or casein (as far as the latter can be differentiated from 

 animal sizing) has been employed. 



(2) Character of sizing refers to the resistance of the sizing and for 

 the present is reported as " excellent," "good," "poor," and "very 

 poor." 



(3) Kind of loading is reported as clay (kaolin), pearl hardening 

 (sulphate of lime), agalite, barytes (blanc fixe or permanent white), 

 silicate of soda, etc. (See also "12. Moisture and Ash.") 



(4) The reaction of a paper may be alkaline, neutral, or acid, and 

 papers are reported as alkaline, neutral, faintly acid, and strongly 

 acid. 



(5) Bleaching agents when present will be reported. 



(6) Ohlorids and sulphates are reported at present as "trace," 

 "low," "medium," and "high." 



SOME TYPICAL PAPER TESTS. 



The accompanying tables are illustrative of the two principal phases 

 of paper tests, i. e., those whose purpose is to determine whether or 

 not the papers delivered comply with the specifications, and those to 

 establish suitability for a given purpose. Some tests made in this 

 Bureau on papers delivered on contract to one of the Federal 

 Departments are reported in Table I, and show the salutary effect on 

 the quality of the goods which was produced by the institution of such 

 examinations. 



[Cir.34l 



