ARSENIATED HIDROGEN GAS, 20t 



gas. The pliial was filled with denfe red fumes, a white 

 flame pervaded the veflel, and a detonation enfued. 



On repeating the experiment with dilute nitric acid, no pHure nitris 

 accenfion took place. The refiduary gas was pure hidrogen,acid. 

 and the water contained arfenic acid. Fuming concentrated 

 nitrous acid therefore is capable of oxidifing the arfenic con- 

 tained in this gas, at the fame time that the oxigen of the 

 acid burns with the hidrogen of the gas, and produces water ; 

 Whereas weak nitric acid is only capable of oxidizing the ar- 

 fenic, without ading upon the hidrogen prefent. 



Into a glafs tube, furniQied with a ftopper at one extre- Nltfo-mHriatle 

 mity, and clofed at the other, I introduced eight cubic *'='<^' 

 inches of arfeniated hidrogen, to which were added two cubic 

 inches of nitro-muriatic acid. After having agit::ted the 

 fluids, on opeaing the tube under water, a diminution of one 

 cubic inch took place. The refiduary gas was pure hidrogen. 

 It is remarkable that, during the addition of the nitro-muriatio 

 acid, a black powder feparated, which again difappeared on 

 agitating the tube. Nitro-muriatic acid ads therefore in the 

 fame manner upon this gas, as oxigenized muriatic acid gas. 

 It effeds firfi a feparation of the metallic arfenic, and then 

 oxiginizes this metal. Liquid oxigenized muriatic acid de- Oxlglnixed nn«- 

 compofes arfeniated hidrogen by mere agitation ; the refidue '■'^''*^ ^^'*^' 

 is hidrogen. Muriatic acid exercifes very little a6tion upon Muriatic add. 

 arfeniated hidrogeii ; but merely diflblves a minute portion 

 of it, which may be expelled again by heat. Concentrated Concentrated 

 acetic acid has no effed upon it. ''"''*' ^"'^' 



Into a glafs cylinder holding eight cubic inches of arfe- Concentrated 

 niated hidrogen, I poured one cubic inch of concentrated ful- fulphuric acid. 

 phuric acid, and then clofed the tube. At the moment of the 

 addition of the acid, the cylinder became lined with a coat Curious pheno- 

 of bright metallic arfenic, fo as to refemble a looking-glafs. menon. 

 On agitating the cylinder, the coating refolved itfelf into a 

 brownifli black powder, which, after a few days, aflumed 

 the colour of Kermes mineral. On opening the cylinder un- 

 der water, a diminution of bulk enfued, and the refiduary 

 gas proved to be hidrogen. The experiment wa-^ repeated, 

 and yielded the fame refults. The fulphuric acid employed The fulphui^c 

 in this experiment, had acquired a penetrating pungent fmell, acid examined. 

 and was examined, after having been neutralized by am- 

 aoiiia, in the following manner : 



5 Ammo- 



