516 
SOLUBILITY  OF  GLUE  IN  GLYCERIN. 
reasonable  in  De  la  Rue's  process,  and  the  writer  testified  to  this 
effect  when  questioned  on  the  subject,  without  having  had  the 
time  to  prove  the  correctness  of  his  inferences  by  direct  experi- 
ment. He  also  unhesitatingly  answered  in  the  affirmative  when 
the  question  was  asked  whether  he  considered  glue  to  be  soluble 
in  glycerin ;  the  fact  that  gum  arabic,  tragacanth,  starch,  &c., 
have  in  glycerin  a  behavior  very  similar  to  that  in  water,  as  far 
as  their  solubility  is  concerned,  naturally  led  to  the  belief  that 
gelatine  would  not  be  an  exception.  He  was  therefore  greatly 
surprised  when  one  of  the  attorneys  engaged  in  the  above  suit 
privately  informed  him  that  experiments  had  been  made  proving 
that  glue  was  totally  insoluble  in  glycerin,  which  would  even  ab- 
stract from  glue  the  moisture  naturally  contained  in  it.  The 
writer  does  not  know  who  made  the  experiments  referred  to  by 
the  legal  gentleman,  but  whoever  may  have  performed  them  has 
done  so  most  superficially,  entitling  his  entire  results  to  no 
credit  whatever,  unless  verified  by  other  more  critical  experi- 
mentists. 
Upon  the  table  will  be  found  a  number  of  specimens,  the  re- 
sults of  my  experiments,  which  I  am  about  to  describe,  and  the 
reactions  of  which  I  shall  exhibit  to  the  meeting.  The  speci- 
mens are  :  (1)  white  glue  macerated  with  glycerin  at  a  tempera- 
ture never  exceeding  75°  F. ;  (2)  white  glue  digested  with  gly- 
cerin in  a  waterbath  for  half  an  hour,  then  macerated  at  ordi- 
nary temperature  for  several  days,  and  afterwards  again  heated 
in  the  waterbath  ;  (3)  white  glue  digested  with  glycerin  for  3J 
hours  at  a  temperature  of  160°  F.  ;  (4)  common  brown  glue 
treated  the  same  way  ;  (5)  white  glue  soaked  in  cold  water  for 
12  hours  and,  after  draining  the  water,  heated  with  glycerin  to 
200°  F. ;  (6)  common  brown  glue  treated  the  same  way  ;  (7)  com- 
mon brown  glue  soaked  in  cold  water  for  3  minutes,  then  with 
the  superficially  adhering  moisture  allowed  to  stand  for  12  hours, 
and  subsequently  heated  with  glycerin  like  the  former. 
The  materials  used  in  these  experiments  were  as  follows  :  The 
glycerin  was  made  by  Wm.  J.  M.  Gordon,  of  Cincinnati,  free 
from  inorganic  impurities,  without  odor,  and  had  a  specific  gra- 
vity of  1*24 ;  the  white  glue  was  thin,  hard,  fractured  readily, 
