128 



THE AMEKICAN MONTHLY 



[July, 



Brazil wood, to whieli a salt of tin 

 has been added. The carmine is 

 more brilliant, but fades faster than 

 the Brazil wood. These inks, of 

 course, do not undergo the same 

 changes by time as iron inks. 



Blue ink is usually made of Prus- 

 sian blue and iron ink. Of late 

 considerable use is being made of 

 . anilin colors of various hues in the 

 manufacture of inks, with a fair 

 promise of permanency. India ink 

 has been used for centuries for 

 writing purposes, and is the most 

 durable of all conceivable sub- 

 stances that can be used in the ma- 

 nufacture of ink, as it consists of 

 pure carbon. It has this disadvan- 

 tage, however, that it rests upon 

 the surface of the paper and does 

 not penetrate the fibres ; therefore 

 it can easily be removed by scrap- 

 ing. It is stated, however, that if 

 it is put in a weak solution of hy- 

 dro-chloric acid, it will be dissolved, 

 or at least so minutely subdivided, 

 that if it is used as ink, it will pe- 

 netrate the surface of the paper 

 and become so intimately attached 

 to its fibres that it cannot be re- 

 moved without removing the fibres 

 also. The same thing will take 

 place if a bit of India ink is placed 

 in a strong solution of caustic po- 

 tash which can be afterward dilu- 

 ted to a proper consistency. Such 

 an ink is absolutely permanent. It 

 cannot be removed by the applica- 

 tion of any chemicals and will en- 

 dure with all of its original color 

 as long as the paper itself, or even 

 longer. 



Professor Silliman says that faded 

 writing, when iron ink has been 

 used, can be restored by brushing 

 over the surface of the paper with 

 a weak solution of gall nuts. 



Forgers often erase writing for 

 the purpose of making changes in 

 its sense. Acids are used to oxid- 

 ize the ink. Strong alkalies are 



used, and sometimes the ink is 

 bleached by the use of chlorine. 

 Modem paper, however, generally j 

 contains a certain amount of color- 

 ing matter, particularly ultramarine. 

 Each of these processes will dis-l 

 charge the color of the paper and] 

 leave a blotch, so that forgers arej 

 often compelled to resort to scrap- 

 ing. This can almost always be de- 

 tected by examining the surface- 

 with a microscope, and the marksj 

 of the scratches can be seen. Thei 

 fibres of the paper will be cut, theirij 

 direction will be changed and the 

 surface of the paper roughened. If 

 a piece of paper so tampered with 

 be placed in water, it will absorb 

 the moisture much faster than other 

 parts of the paper. If the paper is 

 quite thick, it is recommended to 

 use melted parafline, turpentine, or 

 benzole for the same purpose. 



If an ink mark is drawn across 

 such a scratched place, the edges 

 will look blurred instead of being 

 sharply defined, as they would be 

 upon any other part of the paper. 

 This blurring can be seen with the 

 microscope if it cannot be detected 

 by the naked eye. In order to 

 avoid this blurring, the forger is 

 accustomed to restore the surface 

 with gum water, or varnish, or some 

 other glaze. This, however, can be 

 detected by the microscope as the 

 edges of the glaze look different 

 from the surface of the paper. It 

 can also always be detected chemi- 

 cally. The smoothness of the sur- 

 face of paper is produced not by 

 any glazing applied to it, but by 

 immense pressure from smooth 

 heavy rollers, and nothing which 

 is not contained in the substance of 

 the paper can be dissolved from this 

 surface by chemicals. Artificial 

 glazing always differs from the na- 

 tural glazing. Starch will turn blue 

 by the application of iodine ; size 

 and gelatine are browned by the 



