of Arsenic a7id Antimony. 405 



in ; scarcely any of the latter was lost by volatilization. This 

 alloy wa^ cast and divided into eight parts equal by weight. 

 Ihree ot these parts gave abundant arsenical stains in the hy- 

 drogen apparatus : here the proportions are one and a half 

 part of arsenic to 1500 parts of zinc. 



Two parts out of the eight were fused with 400 grains more 

 zinc, cast and divided into five equal parts by wei^/ht; two 

 out of the five parts were placed in the hydrogen ap'par'atus; 

 very faint but characteristic arsenical stains were obtained J 

 here the proportion of arsenic to zinc was four parts of the' 

 former to 20,000 of the latter, or one part to 5000. This ap- 

 peared to be the minimum quantity capable of being detected 

 m the apparatus. 



The next experiments were for the purpose of ascertaining 

 the minimum quantity of arsenious acid which could be de- 

 tected in the apparatus. The zinc employed was from a difl 

 ferent sample to that used in the first set, and was previously 

 well tested and found incapable of afibrding any stains. 

 _ 2-24 grs. of recently sublimed arsenious acid were dissolved 

 in sixty measures of water; the quantity of metallic arsenic 

 = 1*69 gr. 



Haifa measure of the solution, when placed in the hydro- 

 gen apparatus with zinc and sulphuric acid, gave several 

 strongly marked arsenical stains ; the quantity of metal was 

 therefore = -01407. 



One-third of a measure of the solution gave several faint 

 but characteristic arsenical stains ; the metal = -00938. 



One-sixth of a measure of the solution gave only two or 

 three very faint stains; the metal = -00469. This was the 

 minimum quantity. 



The next experiments were made upon alloys of antimony 

 and zinc. -^ 



200 grs. of zinc were fused and 1 grain of antimony stirred 

 into the fused mass ; the alloy when cold was introduced into 

 the hydrogen apparatus, together with diluted sulphuric acid ; 

 large and abundant antimonial stains were obtained. 



200 grs. of zinc were fused and -2 gr. of antimony stirred 

 into the fused mass; the alloy when cold was placed in the 

 apparatus; abundant antimonial stains were obtained : the pro- 

 portion in this case of antimony to zinc was as 1 to 1000. 



400 grs. of zinc were fused and -4 grain of antimony stirred 

 in; the alloy was divided into eight parts; one of these parts 

 was again fused with 200 grains of zinc, and the alloy thus ob- 

 tained was placed in the apparatus; abundant and character- 

 istic antimonial stains were obtained : the proportion vf an- 

 timony to zinc in this case was as 1 to 5000. 



