67 
the formaldehyde was suspended in the mouth of the bottle, the per- 
manganate dropped in from a piece of glazed paper, the whole let 
down quickly into the bottle by a string, and the cork securely placed. 
After a few seconds a vigorous action began, which seemed to be 
over in about 5 minutes. About 15 minutes, however, were allowed 
to elapse before the crucible was removed. By repeatedly rolling 
the cyanide solution over the side of the bottle the formaldehyde was 
soon absorbed (in about half an hour). After the odor of formalde- 
hyde could not be detected the contents of the bottle were trans- 
ferred by thorough washing to a 500 c. c. flask containing an excess 
of decinormal silver nitrate (about 10 c. c.) acidified with nitric acid. 
The volume was made up to the mark, the flask thoroughly shaken, 
250 c. c. of the filtrate titrated with sulphocyanate solution, and cal- 
culation made as already described. 
Method of procedure for the residue in the crucible . — After the crucible 
was removed, the contents were thoroughly extracted with water and 
filtered into a 250 c. c. flask. The volume was made up to the mark 
and 50 c. c. of this liquid were added to about 15 c. c. of the cyanide 
solution. After stirring, it was poured into an excess of acidified 
silver nitrate solution, which was stirred until the precipitate col- 
lected into a clot. The clear filtrate from the precipitate was then 
titrated with sulphocyanate solution for excess of silver. 
Table 6. — Results of experiments in glass bottles. 
Experiment, 
date, etc. 
Size 
of 
bot- 
tle, 
liters. 
For- 
ma- 
lin 
(40 
per 
cent) 
by 
vol- 
ume. 
KMn 
0,. 
For- 
malde- 
hyde 
found 
in 
bottle. 
For- 
malde- 
hyde 
found 
in 
resi- 
due. 
Total of 
formal- 
dehyde 
found in 
bottle 
and 
residue. 
Remarks. 
c. c. 
Gm. 
Per ct. 
Per ct. 
Per ct. 
I 
Aug. 15,1905 
24 
1 
0.5 
33.03 
KMnO< in small needle crys- 
tals. 
II 
Aug. 16, 1905 
24 
1 
0.5 
33.52 
38.25 
71.77 
Do. 
III 
Aug. 18, 1905 
18 
1 
0.5 
32. 47 
40. 35 
72.82 
Do. 
IV 
Aug. 17, 1905 
18 
0.7 
0.35 
35.48 
33.86 
69.34 
KMnO< ground to moderately 
fine powder. 
V 
Aug. 18, 1905 
18 
0.7 
0. 35 
36. 53 
35. 20 
71.73 
Do. 
VI 
do 
24 
1 
0.5 
35. 11 
Do. 
VII 
Aug. 21, 1905 
18 
0.7 
0. 35 
37 
32.20 
69. 20 
Do. 
VIII 
Aug. 22,1905 
18 
0.7 
0. 35 
37.83 
32. 76 
70. 59 
Do. 
IX 
Aug. 19, 1905 
18 
0.5 
0.25 
33.28 
38. 10 
71.38 
Do. 
X 
Aug. 25, 1905 
18 
0.7 
0.4 
34. 37 
25. 16 
59.53 
Do. 
XI 
Aug. 28, 1905 
18 
1 
0. 39 
25.20 
42.79 
67. 99 
Do. 
XII 
Jan. 3, 1906, 41 ° F. 
18 
0.7 
0.35 
30. 84 
39.09 
69.93 
Do. 
XIII 
Jan. 5, 1906,41° F. 
18 
0.7 
0. 35 
30 
34.1 
64.1 
Do. 
XIV 
Feb. 8, 1906, 34 °F. 
18 
0.7 
0.35 
30.1 
34. 15 
64. 16 
Do. 
XV 
Feb. 3, 1906, 20° F. 
18 
0.7 
0.35 
28.26 
Do. 
