1282 Wisconsin Academy of Sciences, Arts , and Letters. 
That it is necessary for the solution to stand a considerable 
length of time is apparent from the following experiments, all 
of which experiments were made under exactly the same con¬ 
ditions. The solution of the dioxide in hydrochloric acid was 
brought to boiling, a saturated solution of sodium acid sulphite 
was added, the solution allowed to stand the requisite length 
of time, then brought on a Gooch platinum filter, washed with 
water until the filtrate no longer showed chlorides, after which 
it was washed with 15 cc. of alcohol and dried at 105°. 
Solution allowed to stand two hours. 
Te required 
Te obtained 
error 
.1609 gm. 
.1586 gm. 
— .0023 gm, 
.1609 
.1590 
— .0019 
.1767 
.1744 
— 0023 
Allowed to stand six hours. 
Te required 
Te obtained 
error 
.1609 gm. 
.1600 gm. 
— .0009 gm. 
.1609 
.1603 
— .0006 
.1374 
.1366 
— .0008 
.1527 
.1517 
— .0010 
Allowed to stand twenty-four hours. 
Te required 
.1609 gm. 
.1609 ~ 
.1726 
.1286 
Te obtained 
.1615 gm. 
.1618 
.1730 
.1289 
error 
+ .0006 gm. 
+ .0009 
+ .0004 
+ .0003 
After tellurium, which has been precipitated by means of 
sodium sulphite and hydrochloric acid, has been washed 
thoroughly with water and alcohol, it oxidizes very slowly even 
when heated as high as 200°, as evidenced by the following data: 
Length of time of heating Temperature Te (1) Te (2) 
15 minutes..... 105° .1619 gm. .1620 gm. 
15 “ . 105° .1619 .1620 
1 hour ... 120°-130° .1620 .1622 
1 “ . 200° .1620 .1623 
PRECIPITATION BY MEANS OF SULPHUR DIOXIDE. 
By the treatment of tellurium dioxide dissolved in hydro¬ 
chloric acid with a freshly saturated solution of sulphur diox¬ 
ide and allowing to stand for 24 hours, the following results 
were obtained: 
