1284 Wisconsin Academy of Sciences , Arts , and Letters. 
A 15 per cent solution of hydrazine hydrochloride along with 
sulphur dioxide gave 
Te required 
.2212 gm. 
.1435 
.1605 
.1072 
Te obtained 
.2210 gm. 
.1434 
.1607 
.1070 
Error 
— .0002 
— 0001 
+ .0002 
— .0002 
A ten per cent solution of the hydrazine hydrochloride with 
sulphur dioxide yielded. 
Te required 
. 1658 gm. 
.1642 
.1268 
.1422 
Te obtained 
.1656 gm. 
.1637 
.1264 
.1420 
Error 
— .0002 
— .0005 
— .0004 
—.0002 
That hydrazine must be present in sufficient quantity is evi¬ 
denced hy the following series of tests in which a 6 per cent 
was used along with sulphur dioxide and the solution boiled 
for a few minutes other conditions being exactly the same as 
in the preceding series of experiments. 
Te required 
Te obtained 
Error 
.1508 gm. 
.1374 gm. 
— .0134 
.1701 
.1443 
— .0258 
.1608 
.1535 
— .0073 
.1521 
.1140 
— .0381 
.1903 
.1781 
— .0122 
The following two experiments were made with a large ex¬ 
cess of sulphur dioxide water along with a 6 per cent solution 
of hydrazine and the solution heated six hours: 
Te required Te obtained Enor 
.1680 gm. .1545gm. —.0135 
.1516 .1416 —.0100 
The method which has been used in this laboratory for a 
number of years and which has proven the most satisfactory 
for the gravimetric determination of tellurium is as follows: 
The tellurium either as derivative of the dioxide or as a tel- 
lurate, should he present in a solution which has an acidity of 
approximately ten per cent of hydrochloric acid, and it is pre¬ 
ferable to have the solution sufficiently concentrated, otherwise 
the fine state of division of the precipitate will render it unsatis¬ 
factory for washing. The solution is heated to boiling and 15 
cc. of a saturated solution of sulphur dioxide added, then 10 cc. 
