IS OP Till: AJSBRIOAN ACADEMY. 



phosphorus is necessary. The color of the bands 



mewhat resembling that from hydrogen sul- 



,,1,1,1,.. Hydrochloric acid make- the band a bright lemon yellow, but 



h ut ii length. The yellow turns Blowly brown when 



i to light Auric chloride acts very slowly, giving at first a 

 brownish red, which changes to purple Ammonia acts 

 -\!y than on the arsenic band, giving a less intense black. 



The 'Solutions used were made from a sample of pure tar- 

 tar emetic, which had been shown to be free from arsenic. They con- 

 bively L.O, 0.1, and 0.01 mg. of antimonious oxide per 

 io centimeter. Volumes corresponding to 10, 30, ■ '•', and To mmg. 

 of the oxide were added to separate bottles and the reduction carried 

 < . 1 1 fur thirty minutes. No color was obtained in any ca le. Hydrochlo- 

 ric acid did imt develope. Auric chloride brought out slowly a purple 

 duller finally than that of a similarly treated arsenic band. Am- 

 monia turned the band quite quickly black, and a comparison with the 

 ammonia standards showed amounts equal to about 20 to 40 

 per the arsenic values. On further reduction for thirty mini; 



with fresh strips, there was no additional deposit on the paper wh 

 ild be developed by ammonia Continuing the experiments, it was 

 ry to add loo mmg. of antimonious oxide before any vis- 

 ible band was obtained, and 200 mmg. before the band appeared to be 

 ■mie length as that from 30 mmg. of arsenious oxide. The color 

 was a taint gray when first visible ; darker with increasing amounts. 

 The development with hydrochloric acid and auric chloride or with 

 ammonia showed of curse that the paper had been originally affected 

 a much greater length than was then visible. 

 These results agree with those obtained by Franceschi, 27 who 

 found by the action of stibine on mercuric chloride a white body to 

 which he gave the formula SbHHg a Cl 3 , analogous to the formula as- 

 ted by him to the red arsenic compound. Dowzard, 28 also, was 

 unable to obtain a stain on mercuric chloride paper from 0.01 

 0.1 mg. of tartar emetic, while from 0.2 mg. he got a faint black- 

 i b brown color, a result which is essentially confirmed by our 

 experiment 



' f Reagents. From the necessary amounts of 



b substanc shown by the above trials, approximately equal 



•r bands were prepared from arsine, stibine, phosphine, and hydro- 



" 13 •()). »» Jour. Chem. Soc, 79, 716 (1901). 



