16  PHARMACEUTICAL  NOTES  OF  TRAVEL. 
none  had  a  more  practical  interest  for  me  than  the  chemical 
works  of  Roberts,  Dale  &  Co.,  Cornbrook  Holme.  The  chief 
products  of  this  establishment  are  connected  with  dyeing  and 
calico  printing ;  in  addition  to  murexide  already  spoken  off  the 
following  are  remembered  as  interesting : — 
The  protochloride  and  perchloride  of  tin  were  made  in  large 
earthen  vessels  adjoining  each  other  ;  the  N05  used  for  perox- 
idizing  the  metal  in  preparing  the  perchloride  being  decom- 
posed and  given  off,  as  N02  was  passed  into  the  other  to  ac- 
complish its  deoxidation.  Oxalic  acid  is  made  under  their  own 
patent,  by  calcining  together  wood  and  caustic  alkali,  which 
produces  oxalate  of  the  alkali,  a  very  soluble  salt,  easily  ob- 
tained in  solution,  decomposed,  and  the  acid  separated  and  crys- 
tallized. 
Nitric  acid  is  distilled  in  the  usual  way,  liberated  from  ni- 
trate of  soda  by  sulphuric  acid,  and  the  refuse  sulphate  of  soda 
is  conveyed  to  another  v^orks,  where  it  is  converted  into  carbonate 
of  soda  ;  the  apparatus  for  distillation  is  of  stone,  the  receivers 
being  arranged  like  Woulf's  bottles.  Large  quantities  of  soap  are 
made  in  this  establishment ;  I  observed  nothing  peculiar,  how- 
ever, in  the  process.  An  arrangement  for  the  distillation  of 
acetic  acid,  which  they  make  from  acetate  of  lime  of  commerce 
by  muriatic  acid,  struck  me  as  economical  of  space  and  very 
convenient ;  from  the  still,  which  is  near  one  corner  of  the  room, 
rises  a  tube,  which  passes  round  the  entire  wall  near  the  ceiling, 
at  a  slight  inclination,  being  surrounded  by  a  closed  trough  of 
cold  running  water,  by  which  the  acid  is  effectually  condensed,  and 
poured  out  at  a  suitable  position  into  the  vessels  provided.  The 
acid  requires  further  rectification. 
The  manufacture  of  starch  and  British  gum  is  on  a  large 
scale.  Wheat  is  the  material  employed  for  producing  the  better 
qualities  of  starch ;  the  flour  is  fermented,  mixed  with  a  large 
body  of  water,  and  transferred  to  shallow  vats,  slightly  inclined 
so  as  to  run  off  the  refuse,  and  allow  the  pure  starch  to  deposit. 
The  refuse  is  used  as  a  size  by  calico  printers. 
Inferior  qualities  of  starch  are  made  from  rice  and  a  crude 
sago  found  in  the  London  market;  the  latter  requires  only  bleach- 
ing ;  they  are  said  to  lose  their  gloss  more  readily  by  moisture. 
Blueing  starch,  which  is  accomplished  by  diffusing  in  it  a  minute 
quantity  of  ultra-marine,  improves  it  for  laundry  uses. 
