310 
NOTE  ON  CHEAP  GLYCERIN. 
tion  to  different  kinds  of  cheap  glycerin  in  our  market,  of  which 
heretofore  I  had  no  knowledge, — namely,  to  an  article  sold  by 
wholesale  dealers  under  the  name  of  "  concentrated  glycerin," 
and  which  I  am  informed  is  manufactured  in  this  city ;  to  an 
article  said  to  be  made  by  Merck,  of  Darmstadt ;  and  to  an  arti- 
cle of  English  origin,  manufacturer's  name  not  given.  Of  the 
former  two  I  received  specimens ;  the  last  1  have  never  seen, 
but,  if  my  information  is  correct,  it  is  not  better  than  the  former, 
while  it  is  held  at  a  higher  price  than  the  "concentrated.'' 
The  two  specimens  were  tested  in  a  similar  manner,  as  de- 
scribed in  my  former  paper,  and  were  found  unadulterated. 
Litmus,  alcohol,  ferrocyanide  of  potassium,  acetate  of  lead  and 
chloride  of  calcium  had  no  effect;  sulphuric  acid  yielded  a  clear 
mixture,  gradually  assuming  a  yellowish  tint ;  oxalate  of  soda 
rendered  them  slightly  turbid ;  nitrate  of  baryta  produced  a 
turbidity  with  Merck's,  none  with  the  "  concentrated  ;"  nitrate 
of  silver  produced  a  milkiness  in  the  former,  a  slight  turbidity  in 
the  latter ;  on  heating  to  the  boiling  point  they  both  turned 
brown.  The  specific  gravity  of  Merck's  was  1*247 ;  of  the 
concentrated,  1*251. 
The  Vienna  glycerin  had  been  kept  alongside  of  these  speci- 
mens for  about  three  months ;  it  has  acquired  a  decided  rancid 
odor.  A  specimen  which  had  been  kept  by  a  friend,  part  of  the 
time  exposed  to  the  sun,  had  a  much  stronger  odor.  Merck's 
had  acquired  a  similar  odor,  though  not  quite  as  strong.  The 
"concentrated"  has  a  peculiar,  slight,  not  a  rancid  odor,  which 
during  that  time  has  not  increased,  but  rather  seems  fainter. 
I  do  not  regard  these  pure  enough  for  internal  use ;  they  may 
answer  for  some  external  preparations,  however,  where  low  price 
is  a  consideration.  On  that  account,  and  for  the  absence  of  the 
rancid  odor,  I  think  the  concentrated  to  be  preferable,  which  is 
likewise  less  contaminated  with  saline  compounds. 
I  may  state  yet  that,  when  diluted  with  distilled  water  and 
kept  for  two  or  three  months,  Bowers'  inodorous  glycerin  re- 
mained perfectly  limpid,  while  the  Vienna  and  Western  glycerin 
produced,  in  the  course  of  two  or  three  months,  a  quantity  of 
confervas.  This  may  probably  be  another  test,  not  so  much  for 
the  absolute  purity,  but  rather  for  the  presence  or  absence  of 
those  odorous  organic  compounds. 
