Headden — Tungstous Oxide, new Oxide of Tungsten. 283 



The remainder of part 2 was persistently boiled witli slightly 

 diluted hydric nitrate, which attacks the iron and tin com- 

 pounds much more readily than it attacks the crystals. The 

 residue after being purified amounted to 42 per cent of the 

 original quantity taken. 



Neither the mixture itself nor the purified residue impart 

 any color to a boiling concentrated solution of potassic hydrate, 

 nor is there any evolution of ammonia or other reaction, but if 

 the crystals are first digested with cold aqua regia and then 

 potassic hydrate be added, the solution becomes brown upon 

 standing, probably due to the formation of WO„. The puri- 

 fied residue consisted very largely of the triangular prisms ; 

 some of the crystalline aggregations remained and the six- 

 sided plates were still recognizable. When heated in the air 

 it did not ignite but was slowly converted into a yellow pow- 

 der. This residue was analyzed with the following results. 

 Analysis III. 



At. eq. 



Cb 6-56 6-98 4'9 \ 



W 76-12 41-37 29-1 j 



Fe ... 9-06 16-18 11-4 



Sn 1-68 1-42 TO 



O 6-34 39-63 28"0 1 



99-76 



The gain upon ignition equalled 2066 per cent. If we cal- 

 culate the columbinm, tungsten and oxygen to one hundred 

 we obtain Cb 7*37, W 85-57, O 7*12 = 10O00. 



Portion No. 3, that is, the coarsest portion of the residue, was 

 passed through a 148 mesh bolting cloth and the small portion 

 which remained on the cloth was reserved for subsequent 

 study. The portion used for analysis consisted of triangular 

 prisms, which constituted as much as and possibly more than 

 85 per cent of the whole mass ; the rest was made up of crys- 

 talline aggregations with a few of the six-sided plates noticed 

 in the last sample. When ignited in the air it oxidized with- 

 out incandescence to a yellow powder ; the gain equalled 

 19 10 per cent ; the analysis No. IV gave : 



At. eq. 



Cb .... 



1-46 



1-55 



1-34 



W .... 



86-64 



47-09 



40-94 



Fe ... 



4-32 



7-71 



6-70 



Sn .... 



.... 1-36 



1:16 



1-00 







6-32 



39-50 



34-35 



42-28 1-22 



34-35 1-00 



100-10 



