442 
THALLIUM  AND  MAGNESIUM  ALLOYS. 
this  till  all  bitter  taste  is  gone.  An  aqueous  solution  contain- 
ing 10  per  cent,  of  purified  caramel  is  gummy,  and  forms  a  jelly. 
When  a  solution  of  caramel  in  water  is  evaporated  in  vacuo, 
(small  vacuum  pan  as  used  in  sugar  refineries,)  it  dries  up  to  a 
black  shining  mass,  freely  soluble  again  in  water,  hot  or  cold  ; 
but  if  the  solution  is  evaporated  on  a  water-bath  to  dryness  in 
contact  with  air,  the  whole  mass  becomes  insoluble  in  water 
either  hot  or  cold. 
A  very  •small  proportion  of  caramel  gives  to  a  large  bulk  of 
water  the  dark  brown  tinge  known  as  sepia.  An  impure  but 
pretty  strong  solution  of  crude  caramel  (i.  e.,  not  purified  by 
dialysis  or  alcohol — hence  the  term  impure  for  the  solution)  is 
sold  in  London,  under  the  name  of  CofFeena,  in  small  bottles  at 
Is.  per  bottle,  to  be  had  in  many  oil  and  color  shops  in  the 
metropolis  ;  it  is  used  in  teaspoonfuls  to  improve  coffee,  dispens- 
ing with  chicory. 
I  am,  &c,  A.  Adriana. 
London,  May  7. 
P.S. — Treacle  is  not  very  manageable  to  use  for  making  of 
caramel.  The  sugars  should  be  first  dried  at  212°  Fahr.  On 
the  Continent  dry  glucose  is  sometimes  used  instead  of  cane  or 
beet-root  sugar  for  the  purpose  of  making  caramel. — Lond. 
Chem.  News,  May  17,  1867. 
NOTES  ON  THALLIUM  AND  MAGNESIUM  ALLOYS. 
By  S.  Mellor,  Esq., 
Manager  of  the  Magnesium  Metal  Company. 
It  having  been  suggested  that  if  an  alloy  of  thallium  and 
magnesium  could  be  easily  made  into  wire,  it  might  be  found  to 
burn  readily,  and  to  produce  an  intense  bright  green  flame, 
which,  from  its  portability,  would  be  well  adapted  to  some  of 
the  purposes  for  which  a  green  flame  is  required,  some  experi- 
ments have  been  made  with  this  end  in  view. 
It  was  found  that  thallium  alloys  most  readily  with  magne- 
sium, and  in  any  proportions.  The  alloys  are  very  stable,  and 
are  easily  worked  up  into  wire  and  ribbon.  Alloys  containing 
5,  10,  15,  20,  25  and  50  per  cent,  of  thallium  were  prepared. 
