1896.1 *" [Doromus. 



question cas to whether the ink was cosine or not. Experts were called 

 for both sides and the writer was among those retained by the executors. 

 As the right to use reagents on the document was denied all the preliminary 

 tests had to be of a physical character, though they were afterwards veri- 

 fied by chemical tests in court. My attention had been called several 

 years previously to the black appearance of the lips of players using 

 rouge, one kind of which I knew to be eosine. Eosine is irresponsive to 

 yellow rays and seems almost black in the glare of the footlights. Carmine 

 and other reds retain more of their red color. Experiments were there- 

 fore made with different red inks, as carmine, aniline red, safrauine, and 

 eosine, and their appearance noted under monochromatic illumination of 

 , a sodium flame. 



The results were not as pronounced as desired. Recourse was then had 

 to comparing the various inks in strong daylight behind differently colored 

 glasses. The eflects were very striking, especially with the aniline inks 

 since they possess iridescence. 



Colored glasses also greatly aid in the discovery of their fluorescent 

 qualities. 



The ink on the document presented a lustre when illuminated through 

 green glass which was quite different from that of carmine and various 

 aniline inks. 



The fluorescence of eosine may also be enhanced by the use of blue or 

 purple glass. 



These experiments induced the writer to try a spectroscopic examination 

 of inks, both in solution and in form of writing. 



A Zeiss micro-spectroscopic eye-piece and low-power lens were used at 

 first, then a higher power. This test is especially valuable since the docu- 

 ment is uninjured. 



It requires the brightest sunlight as a source of illumination. The ink 

 is viewed by transmitted light and an absorption spectnim is obtained. 

 When mapped the spectra are found to vary. 



This means of identification was, however, not sufficiently developed to 

 enable it to be used in court, nor could it be shown because of the absence 

 of proper facilities. 



At court the preliminary examination of the experts was strengthened 

 by chemical tests applied to the ink on the document and prominently 

 the action of hydrochloric acid which produced a yellow color and by the 

 greenish yellow fiuorescent nature of a solution of the ink. 



The opinion of the experts for the defense that the ink was eosine was 

 corroborated by several ink manufacturers and a well-known importer of 

 aniline dyes. 



In rebuttal it was claimed that the ink was aurine. 



It was necessary to breaVi the evidence going to prove the ink to be 

 eosine since that color was not discovered until 1874, eight years after the 

 date of the will. Aurine was, however, in commercial use in 1865, and 



PROC. AMER. PHILOS. SOC. XXXV. 150. J. PRINTED JULY 2, 1896. 



