﻿164 
  

  

  C. 
  Barus 
  — 
  Hot 
  Water 
  and 
  Soft 
  Glass 
  

  

  (f 
  inch), 
  L. 
  By 
  surrounding 
  this 
  at 
  about 
  two 
  feet 
  from 
  the 
  

   boiler 
  with 
  a 
  narrow 
  cylinder 
  containing 
  water, 
  M, 
  the 
  vapors 
  

   are 
  usually 
  condensed 
  and 
  flow 
  back 
  without 
  giving 
  annoyance. 
  

   In 
  the 
  present 
  experiments, 
  the 
  liquid, 
  k, 
  was 
  naphthaline 
  

   boiling 
  at 
  210° 
  and 
  the 
  vapor 
  bath 
  needed 
  no 
  special 
  attention 
  

   for 
  months. 
  If 
  the 
  bath 
  is 
  well 
  enveloped 
  with 
  asbestos, 
  

   except 
  at 
  the 
  two 
  patches 
  on 
  the 
  bottom 
  where 
  the 
  flames 
  of 
  

   two 
  ordinary 
  Bunsen 
  burners, 
  JP, 
  Q, 
  impinge 
  against 
  free 
  

  

  w^ 
  1 
  

  

  metal, 
  these 
  are 
  quite 
  sufficient 
  to 
  maintain 
  continuous 
  ebulli- 
  

   tion 
  at 
  210° 
  for 
  an 
  indefinite 
  time. 
  It 
  is 
  well 
  to 
  keep 
  M 
  

   supplied 
  with 
  water 
  by 
  aid 
  of 
  some 
  automatic 
  dropping 
  

   arrangement. 
  

  

  4. 
  The 
  charge 
  of 
  laboratory 
  glass 
  specified, 
  being 
  the 
  broken 
  

   capillary 
  tubes 
  of 
  earlier 
  correlative 
  experiments, 
  pulverized 
  

   and 
  sifted 
  to 
  a 
  fine 
  granular 
  powder, 
  was 
  introduced 
  into 
  the 
  

   retort 
  with 
  water. 
  About 
  210 
  grams 
  of 
  glass 
  and 
  50 
  grams 
  of 
  

   water 
  was 
  known 
  to 
  be 
  a 
  promising 
  ratio. 
  The 
  retort 
  was 
  

   then 
  put 
  into 
  the 
  vapor 
  bath 
  and 
  kept 
  at 
  210° 
  for 
  about 
  12 
  

   hours. 
  

  

  On 
  opening 
  the 
  cold 
  retort 
  the 
  glass 
  was 
  found 
  to 
  be 
  quite 
  

   fused 
  down 
  to 
  a 
  resinous, 
  opalescent, 
  very 
  hard 
  and 
  tough 
  

  

  