262  METHOD  OF  IMPARTING  A  RED  COLOR  TO  RONE. 
as  a  masticatory,  to  sweeten  the  breath.  We  have 
in  our  possession  a  specimen  of  the  resin  of  Liquid- 
ambar  presented  by  Mr.  Wayne  of  Cincinnati.  It  con- 
sists of  conglomerated  tears,  varying  in  color  from 
light  yellow  to  black,  and  softens  when  chewed,  like 
tola.  When  boiled  with  milk  of  lime,  the  filtered 
decoction  has  a  light  yellow  color,  and  yields  a  crys- 
talline precipitate  on  adding  muriatic  acid,  like 
benzoin.  These  crystals,  in  hot  water,  saturate 
ammonia,  and  the  neutral  ammoniacal  solution  pre- 
cipitates sesquichloride  of  iron  in  red  flocks.  They 
are  probably  benzoic  acid.  The  figure  in  the  margin  gives  an  idea  of  this 
plant,  and  of  its  close  analogy  to  the  oriental  species  in  the  shape  of  its  leaf 
and  fruit  vessels.] 
A  METHOD  OF  IMPARTING  A  RED  COLOR  TO  BONE  AND  IVORY. 
By  Dr.  J.  C.  Kellermann. 
The  bone  to  be  colored  is  laid  for  fifteen  to  twenty  minutes  in 
very  dilute  cold  nitric  acid  of  the  strength  of  a  good  vinegar ; 
this  dilute  nitric  acid  is  obtained  by  mixing  fully  I  a  litre  of  soft 
water  with  about  13  grms.  of  nitric  acid.  The  bone  is  then  im- 
mersed for  fifteen  to  twenty  minutes  in  a  solution  of  proto- 
chloride  of  tin,  made  by  dissolving  a  piece  of  the  size  of  a  lentil 
in  a  pint  of  water.  The  objects  thus  mordanted  are  then  put 
into  the  following  red-bath,  which  must  first  be  heated  until  it 
begins  to  boil. 
Bed-hath. — For  an  experiment  on  the  small  scale,  take  3  to  5 
grs.  of  fine  red  carmine,  pour  to  it  10  to  12  drops  of  ammonia, 
and  stir  it  up  well  until  the  carmine  is  dissolved  ;  then  add  about 
2  oz.  of  soft  water.  In  this  bath,  when  heated  to  boiling,  the 
objects  must  be  left  for  about  fifteen  minutes.  The  tints  ob- 
tained are  more  vivid  when  the  boiling  of  the  bath  is  not  con- 
tinued whilst  the  objects  are  in  it. 
If  it  be  desired  to  change  the  tint  thus  obtained  (a  very  fiery 
carmine-red)  to  a  more  scarlet  color,  one  of  the  following  methods 
may  be  employed.  When  the  red-bath  begins  to  boil,  and  im- 
mediately after  the  objects  have  been  immersed  in  it,  5  to  10 
drops /of  tartaric  acid  of  the  strength  of  a  good  vinegar  may  be 
added ;  or  the  water  in  which  the  protochloride  of  tin  is  to  be  dis- 
solved may  be  mixed  with  an  extremely  small  quantity  of  English 
sulphuric  acid. — Ohem.  Gaz.,  from  Dingier' §  Polytechn.  Journal 
