42 
PHASEOMANNITE,  A  NEW  KIND  OE  SUGAR. 
and  the  residue  somewhat  reduced  in  the  water-bath,  and  left 
for  twenty-four  hours,  when  a  quantity  of  flat  needles,  concen- 
trically grouped,  which  might  be  taken  for  mannite,  crystallized 
from  it. 
The  crystals  were  freed  from  the  mother-liquor,  pressed  be- 
tween bibulous  paper,  and  dissolved  in  weak  alcohol.  A  small 
quantity  of  gum  and  vegetable  gelatine  separated,  and  were  got 
rid  of  by  filtration.  When  the  alcohol  had  been  distilled  off, 
and  the  aqueous  solution  decolorized  by  animal  charcoal,  it  furn- 
ished, by  spontaneous  evaporation,  beautiful  limpid  prisms,  part- 
ly grouped  concentrically,  very  different  in  their  external  ap- 
pearance from  mannite.  This  body,  which  possesses  a  sweet 
taste,  is  readily  soluble  in  water  and  dilute  alcohol,  but  difficult 
of  solution  or  insoluble  in  absolute  alcohol  and  ether. 
It  loses  water  of  crystallization  in  dry  air,  becomes  dull,  and 
more  difficult  of  solution  in  water,  from  which,  however,  it  sepa- 
rates on  spontaneous  evaporation  with  its  original  amount  of 
water.    At  212°  F.  it  loses  16-5  per  cent,  of  water. 
When  heated,  the  crystals  decrepitate  and  give  off  water;  be- 
tween 802°  and  320°  F.  they  fuse  to  a  colorless  liquid,  which 
solidifies  in  a  crystalline  form  on  cooling ;  when  heated  to  454° 
-472°  F.,  the  body  begins  to  boil,  with  evolution  of  empyreu- 
matic  vapors,  which  diffuse  an  odor  of  burnt  sugar.  The  vapor 
burns  with  a  luminous  flame,  without  smoking.  The  carbona- 
ceous residue  burns  upon  platinum  without  leaving  an"  ash.  When 
mixed  with  soda-lime  and  heated,  the  substance  evolves  no  am- 
monia. 
With  a  solution  of  sulphate  of  copper  and  potash,  it  gives  a 
dark  azure-blue  solution,  which  does  not  deposit  protoxide  of 
copper  either  in  the  cold  or  by  boiling. 
The  behaviour  of  this  body  with  sulphate  of  copper  and  potash, 
and  its  incapability  of  fermentation,  place  it  in  the  same  series 
with  mannite  ;  but  its  behaviour  in  dry  air  and  its  composition 
give  sufficient  cause  to  distinguish  it  strictly  therefrom.  The 
author  therefore  calls  it  phaseomannite. 
The  combustion  of  the  body,  dried  at  212°  F.  with  chromate 
of  lead,  gave  on  the  average  of  three  analyses— 
C  41-0475 
H  6-8649 
0  52-0876 
