PREPARATION  OF  MARKING  INKS  FOR  LINEN. 
33 
one.  It  is  then  sufficiently  hygrometric  to  dissolve  in  the 
water  which  it  derives  from  the  atmosphere ;  and  this  solution, 
with  the  addition  of  yeast,  soon  becomes  converted  into  alcohol 
and  carbonic  acid. 
The  preceding  explains  the  reason  why  sugar  is  found  in 
manna.  If,  under  an  oxydizing  influence,  mannite  is  convertible 
into  sugar,  there  can  be  no  doubt  that  it  may  also  be  produced 
by  the  action  of  deoxidizing  agents  on  the  sugar  itself ;  it  is  thus 
that  it  is  formed  in  the  juice  of  beet-root  submitted  to  viscous 
fermentation. — Comptes  Mendus,  and  Pharm.  Jour. 
PKEPARATION  OF  MARKING  INKS  FOR  LINEN. 
By  Jules  Guiller. 
The  author,  who  has  received  five  years'  exclusive  privilege  in 
Paris  for  the  manufacture  of  marking  inks,  for  the  processes 
which  he  has  invented  for  making  them,  states  that  none  of  the 
marking  inks  used  heretofore  completely  answer  the  purpose  in- 
tended. Some  produce  a  yellowish  stain  on  linen  ;  and  others, 
although  marking  black  in  the  first  instance,  become  gradually 
washed  out.  To  remedy  these  evils,  and  to  avoid  the  use  of  two 
fluids  in  marking  linen,  he  has  devised  three  processes  for  making 
marking  ink,  which  are  as  follows : — 
Formula  TVo,  1. 
Nitrate  of  silver       .       .       .       .11  parts. 
Distilled  water  85  " 
Powdered  gum  arabic  .  .  .20  " 
Carbonate  of  soda  .       .       .    22  " 
Liquor  of  ammonia     .  .        .    30  " 
The  twenty-two  parts  of  carbonate  of  soda  are  to  be  dissolved 
in  the  eighty-five  parts  of  distilled  water  ;  and  this  solution  rubbed 
with  the  gum  in  a  mortar  until  it  is  dissolved.  The  eleven  parts 
of  nitrate  of  silver  are  to  be  dissolved  in  the  twenty  parts  of 
liquor  of  ammonia,  and  then  mixed  with  the  soda  solution.  The 
mixed  fluids  are  then  to  be  warmed  in  a  flask,  by  which  they 
become  at  first  greyish  black,  and  partly  coagulated ;  afterwards 
brown,  and  then  clear ;  and  lastly,  when  the  ink  boils,  very  dark, 
