This is an an example of a early 1870s  De La Rue Ink Trial  Stamp in  Purple Brown.  This stamp was used by De La  Rue  for  ink  trials  and  is  found  attached  to  the  De La Rue   ink  recipe  register.    De  La  Rue  maintained  a   register  of  "'ink  recipes" of  each  new  ink  recipe  prepared  and  used.  The  ingredients  of   the  ink  and  mixing   instructions,   if  any,  were  noted  on  the recipes and a printed example  from  the  final  ink trial after the ink and  color  had  been  approved  was  attached  to  it.  This  was  usually a single or a block of  four  of  the ink  trial  stamp or  a  blank.    Below are two  examples of the  stamps  as  they  appeared on  the ledger  page.   One example is of the Queen Victoria Dummy Stamp  as  shown  in  detail  above.  In  this  case it is a block of four representing a recipe for Chrome Yellow.  The other example  is  typical of the De La Rue label design that was also used.