Konig.] rki^ [June 17, 



The analysis gives B = 0.15; S= 0.1975; C = 0.228; S = O.0301 

 0.1975 O.0301 



«i = X486 ^ ^•^^' ^2 = -42" = ^-^^^^ 

 A = 0.2095 by experiment. 



hence S— B— C = A = 1.0889 ; 8 =■ A—\—h = .1583 



1.0889 

 ^^<^^P=0.1o83=^-S^^- 



Blowpipe reacAions. The mineral decrepitates in the closed tube, simi- 

 larly to the majority of compounds belonging to this group, it melts then 

 at red heat without the formation of a sublimate. Heated with the O. Fl. 

 on charcoal it yields a deep yellow incrustation with a white non volatile 

 fringe, coloring the seam of the flame faintly azure blue (lead). Upon con- 

 tinued blowing a crimson to peach blossom red zone appears between the 

 yellow and white incrustation (silver). The residue gives the reactions of 

 copper and iron with borax and microcosmic salt, and after cupellation. 

 with lead, a considerable silver button. "With potassium iodide and sulphur 

 an intense brick red coating is obtamed (bismuth). In the open tube sul- 

 phurous anhydrite (sulphur) and a minute white sublimate (antimony) are 

 given off", while a yellow residue is produced. Cold concentrated hydro- 

 chloric acid acts very slowly upon the finely pulverized mineral, but the 

 heated acid decomposes it completely and rapidly, leaving flocculent silver 

 chloride. 



Analyses. So intimate is the mixture of Alaskaite and chalcopyrite, that 

 a complete mechanical separation was not feasible. Now it is quite pos- 

 sible to remove the Alaskaite by HCl from the chalcopyrite and barite, but 

 the quantity of copper-iron-bisulfide is always so small (see analyses) that 

 if the iron be taken as representing chalcopyrite, no appreciable error will 

 be committed. A small quantity of the mineral was picked out carefully, 

 leaving only traces of chalcopyrite, for a preliminary analysis. 250 mg. 

 gave : BiA — 160.0 mgr ; PbS04= 38.0 mgr. Ag CI = 23.5 mgr ; CuO r= 

 7.0 mgr; birite = 8.3 mgr. The substance minus barite was 141.7 mg. 

 Calculated upon this number we have : 



Bi^Sg = 73.02 ; PbS = 12.40 ; Ag.,S == 9.06 ; Cu.,S = 6.20 corresponding 

 very closely to the ratio (RS)2o + (BijSg).^! ^^^^ is probably as 1 : 1. A 

 quantitative blowpipe assay gave 7.5 p. c. Ag, or minus barite, 8.90 Ag.^S. 



With less carefully picked material the following 2 analyses were made, 

 A and B, the determinations of Bi and Pb in A being lost : 



