PREPARATION  OF  FANCY  LEATHERS,  ETC.  407 
and  sheep  skins,  which  are  especially  used  for  this  branch  of 
manufacture,   are  softened,  fleshed,   unhaired,   and  raised  or 
swelled  by  methods  similar  to  those  already  described,  but  one 
essential  element  of  success  in  this  kind  of  leather  lies  in  the 
perfect  removal  of  all  lime  from  the  skins,  which  is  effected  by 
plunging  the  well-washed  skins  in  a  bath  of  bran  or  rye  flour, 
which  has  been  allowed  to  enter  into  a  state  of  fermentation. 
The  result  is,  that  the  lactic  and  acetic  acids  generated  by  fer- 
mentation of  the  amylaceous  substances  combine  with  the  lime 
and  remove  it  from  the  skins.    The  other  essential  point  is  the 
mode  of  tanning  the  skins.    Each  skin  is  sewn  so  as  to  form  a 
bag,  and  filled  through  a  small  opening,  with  a  strong  decoction 
of  sumac,  and  after  the  aperture  has  been  closed  the  skins  are 
thrown  into  a  large  vat  containing  also  a  decoction  of  the  same 
material.    After  several  hours  they  are  taken  out,  emptied,  and 
the  operation  i3  repeated.    To  render  these  skins  ready  for 
commerce  it  is  necessary  to  wash,  clean,  and  dye  them.  The 
latter  operation  was  formerly  tedious,  and  required  great  skill, 
but  since  the  introduction  of  tar  colours,  the  affinity  of  which 
for  animal  matters  is  so  great,  it  ha3  become  comparatively  easy. 
The  skins,  after  they  are  dyed,  are  oiled,  slightly  curried,  and 
the  peculiar  grain,  characteristic  of  Morocco  leather,  is  imparted 
to  it  by  means  of  grooved  balls  of  rollers.  There  are  two  inferior 
kinds  of  Morocco  leather  manufactured,  viz.,  those  called  roan, 
prepared  in  a  similar  way  to  Morocco,  but  not  grained,  and 
skivers,  also  prepared  in  the  same  manner,  but  from  split  sheep 
skins.    I  owe  to  the  kindness  of  Mr.  Warren  De  la  Rue  the 
beautiful  specimens  of  leather  before  me,  which  will  enable  you 
to  appreciate  the  various  qualities  of  these  interesting  produc- 
tions. 
Russia  Leather. — The  great  esteem  in  which  this  leather  is 
held  is  owing  to  its  extreme  softness  and  strength,  its  imperme- 
ability, and  resistance  to  mildew,  which  latter  property  is  im- 
parted to  it  by  the  use  of  a  peculiar  oil  in  its  currying,  that  is 
birch-tree  oil,  the  odour  of  which  is  well-known  as  a  distin- 
guishing feature  of  Russia  leather.  As  to  its  preparation,  I  will 
merely  state  that  it  is  very  similar  to  that  of  Morocco,  with 
these  differences,  that  hot  solutions  of  willow  bark  are  used  in- 
stead of  sumac  ;  that  it  is  generally  dyed  with  sandal  wood  and 
