Am'£y r 'lS11™' }  Notes  on  Estimation  of  Nitroglycerine.  197 
The  nitrogen  determinations  were  made  as  follows :  Approxi- 
mately one  gram  of  the  ten  per  cent  alcoholic  solution  was  used  for 
analysis.  Where  tablets  and  triturations  were  analyzed  they  were 
first  extracted  with  anhydrous  ether,  and  the  ether  extracts  were 
evaporated  to  dryness  under  reduced  pressure  at  room  temperature. 
The  residue  was  taken  up  in  1  to  2  c.c.  alcohol  and  collected  at  the 
bottom  of  the  flask.  Upon  this  alcoholic  solution  one  gram  of 
salicylic  acid  was  placed  and  then  the  Kjeldahl  flask  was  cooled  in  a 
freezing  mixture.  Upon  this  40  c.c.  of  the  customary  salicylic  acid 
in  sulphuric  acid  solution  (previously  chilled)  was  poured  and  then 
the  mixture  was  allowed  to  warm  to  room  temperature,  with  occa- 
sional agitation.  The  nitration  mixture  was  reduced  by  the  gradual 
addition  of  2  grams  of  zinc  dust,  and  then  the  reduction  was  com- 
pleted by  allowing  the  reaction  to  continue  for  six  hours.  The 
mixture  was  heated  gently  for  five  minutes,  ten  grams  of  potassium 
sulphate  was  added,  and  the  Kjeldahl  determination  was  then  finished 
in  the  usual  manner,  using  N/20  solutions. 
The  following  table  gives  the  results  of  analyses  on  tablets,  some 
prepared  experimentally  and  some  commercially: 
Preparation  analyzed. 
r.  Nitroglycerine  sol. . 
2.  Nitroglycerine  trit. 
3.  Compressed  tablets 
4.  Compressed  tablets 
5.  Compressed  tablets 
6.  Compressed  tablets 
7.  Compressed  tablets 
8.  Moulded  tablets. . . 
9.  Moulded  tablets. . . 
10.  Moulded  tablets. . . 
EX.  Moulded  tablets. . . 
12.  Moulded  tablets. . . 
Nitroglycerine 
calculated 
gm.  per  tablet. 
0. 0007744 
0. 0005194 
0. 0007732 
0. 0006234 
o. 0004015 
0. 0006493 
0. 000658 
,0. 00053S1 
0. 000720 
0. 000688 
Found 
Kjeldahl. 
9.83% 
9.65% 
9.66% 
9.82% 
9.56% 
-9.7i% 
9-99% 
9.63% 
0007228 
0007039 
0.0004557 
o. 0004768 
o. 0004546 
0.0007395 
o. 0005298 
o. 0005298 
0. 0003512 
o. 0003474 
o. 0006328 
o. 0006328 
o. 0006280 
0.0005237 
0. 000629 
Found 
Scoville.  per 
9.75% 
9-87% 
10.03% 
9-88% 
0. 0007044 
0. 0006843 
o. 0007083 
0. 0004540 
0. 0004508 
o. 0007038 
0. 0006967 
0. 0006850 
0.0005273 
0.0005559 
0.0005559 
o. 0003552 
o. 0003596 
o. 0006588 
0. 000616* 
o. 0005085 
o. 0005184 
0. 0006836 
o. 0006480 
*  This  analysis  was  made  three  months  after  the  Kjeldahl. 
