NOTE  ON  THE  CRYSTALLIZATION  OF  GLYCERIN.  163 
attract  the  attention  of  scientific  men,  and  Mr.  Cross's  remarks 
on  the  vegetable  productions  of  this  vast  region  must  interest 
botanists  and  chemists.  Mr.  Clements  E.  Markham,  in  his 
official  memorandum,  states  that  "  Mr.  Cross  deserves  great 
credit  for  the  skilful  and  energetic  way  in  which  he  performed 
this  di  fficult  service."  It  appears  that  a  portion  of  the  seed 
obtained  has  been  supplied  to  the  Mexican  Government,  who 
are  anxious  to  cultivate  the  cinchona  plant. — London  Chemist 
•  and  Druygist,  Dec.  15,  1866. 
NOTE  ON  THE  CRYSTALLIZATION  OF  GLYCERIN. 
By  William  Crookes,  F.R.S. 
My  attention  has  been  drawn  by  my  friend  Dr.  W.  S.  Squire, 
of  the  firm  of  Burgoyne,  Burbidges  and  Squire,  Coleman  Street, 
to  the  hitherto  unobserved  fact  of  the  crystallization  of  large 
masses  of  glycerin  during  the  recent  cold  weather. 
About  five  tons  of  glycerin,  in  casks  of  eight  cwt.  each,  were 
recently  imported  by  this  firm  from  Germany.  When  they  left 
the  factory  the  contents  were  in  their  usual  state  of  viscid  flu- 
idity ;  but,  on  arriving  in  London,  they  were  found  to  have 
solidified  to  a  solid  mass  of  crystals,  so  hard  that  it  required  a 
hammer  and  chisel  to  break  it  up. 
A  large  block  of  this  solid  glycerin,  weighing  several  hundred- 
weight, suspended  in  a  somewhat  warm  room,  took  two  or  three 
days  to  liquify,  and  a  thermometer  inserted  in  the  fusing  mass 
indicated  a  constant  temperature  of  45°  F.  In  small  quantities 
the  crystals  rapidly  fuse  when  the  bottle  containing  them  is 
placed  in  warm  water.  The  original  glycerin  was  pale  brown  ;, 
the  crystals  formed  from  it  are  nearly  white,  whilst  the  liquid 
which  drains  away  from  it  is  dark  brown.  In  quantity,  the  solid 
glycerin  looks  very  like  a  mass  of  sugar  candy.  The  isolated 
crystals  are  sometimes  as  large  as  a  small  pea  ;  they  are  bril- 
liant, and  highly  refracting ;  when  rubbed  between  the  fingers 
they  are  very  hard,  and  they  grate  between  the  teeth.  Their 
form  appears  to  be  octahedral,  but  this  is  difficult  to  ascertain 
accurately,  owing  to  the  viscidity  of  the  mother  liquor  which 
adheres  to  them. 
