122 
Glass  Manufacture 
(Am.  Jour.  Pharm. 
(     February,  1920. 
Except  in  some  of  the  larger  works,  very  crude  methods  are  em- 
ployed in  the  handling  and  treatment  of  materials,  and  in  this  the 
glass  trade  may  be  considered  to  be  very  backward.  The  best 
methods  of  grinding  and  mixing  batch  and  cullet,  and  the  use  of 
magnetic  separators,  conveyors,  etc.,  in  the  industry  really  require 
investigation.  The  treatment  of  different  kinds  of  material  re- 
quires special  study.  On  the  proper  treatment  of  the  materials 
and  the  mixing  of  the  batch  depends  the  quality  of  the  glass,  and 
the  saving  of  loss  due  to  stones  and  cords.  Glass  makers  are  hard 
on  machinery,  which  they  cordially  dislike,  but  which  they  will 
have  to  put  up  with  if  the  trade  is  to  hold  its  ov/n  against  foreign 
competition. 
Regenerative  or  recuperative  glass-fired  pot  furnaces  have  for 
some  time  been  in  use  in  this  country,  but  recent  attempts  to  work 
them  intensively  have  not  met  with  a  great  measure  of  success  on 
account  of  the  repeated  failure  of  the  refractory  materials  in  the  fur- 
naces and  pots.  When  working  at  full  pressure,  and  using  open 
pots,  it  is  possible  to  fill  the  pots  after  the  blowers  have  stopped 
work  in  the  evening,  and  to  found,  plain,  and  cool  off  the  metal  by 
the  next  morning.  Thus  it  is  possible  to  work  the  factory  with  a 
single  shift  of  blowers  working  about  48  hours  a  week.  However, 
to  work  this  single  shift  the  glass  must  be  got  ready  within  the  twelve 
hours. 
Continental  glass  manufacturers  have  succeeded  in  working  in 
this  way,  and  for  the  sole  reason  that  they  are  provided  with  superior 
refractory  materials.  It  appears  that  satisfactory  fire  clays  exist 
in  this  country,  and  the  production  from  them  of  suitable  fire  bricks, 
siege  blocks,  pots,  etc.,  should  not  present  insuperable  difficulties. 
The  problems  await  the  early  attention  of  the  Glass  Research  As- 
sociation. The  matter  is  one  of  vital  importance,  for  the  saving  of 
fuel  alone  is  50  per  cent,  of  that  used  in  the  non-regenerative  fur- 
naces. 
The  position  with  regard  to  tank  furnaces  is  more  satisfactory, 
but  much  may  be  done  towards  the  improvement  of  the  refractories 
used  in  their  construction.  The  increase  in  the  cost  of  fuel  and 
labor  also  calls  for  close  attention  to  improvements  in  gas  producers 
and  mechanical  accessories. 
During  the  war  considerable  progress  was  made  in  the  manufac- 
ture of  mould-blown  goods,  such  as  electric  lamp  bulbs,  and  scientific 
and  illuminating  hollow  ware,  which  differ  from  common  bottles 
