﻿in 
  Their 
  Thermodynamic 
  Relations. 
  165 
  

  

  body, 
  containing 
  white 
  inclusions 
  of 
  partially 
  converted 
  water 
  

   glass, 
  but 
  otherwise 
  homogeneous. 
  About 
  240 
  grams 
  were 
  

   removed 
  from 
  the 
  retort, 
  to 
  which 
  the 
  glass 
  adhered 
  so 
  firmly 
  

   that 
  a 
  cold 
  chisel 
  and 
  hammer 
  were 
  necessary 
  for 
  the 
  process. 
  

   Looking 
  through 
  the 
  retort 
  endwise, 
  it 
  was 
  seen 
  to 
  be 
  about 
  

   one-half 
  filled 
  and 
  the 
  top 
  surface 
  of 
  the 
  glass 
  smooth, 
  as 
  

   shown 
  in 
  fig. 
  2a. 
  So 
  excess 
  of 
  water 
  was 
  apparent, 
  all 
  having 
  

   been 
  absorbed. 
  Surfaces 
  of 
  the 
  glass 
  broken 
  from 
  the 
  retort 
  

   were 
  black 
  with 
  iron 
  oxide. 
  

  

  Heated 
  in 
  the 
  air 
  above 
  a 
  candle 
  flame 
  the 
  glass 
  melts, 
  swells 
  

   up 
  enormously 
  with 
  loss 
  of 
  water 
  to 
  a 
  silvery 
  white 
  pithlike 
  

   pumice. 
  The 
  experiment 
  recalls 
  the 
  behavior 
  of 
  a 
  pharaoh 
  

   serpent, 
  but 
  is 
  not 
  quite 
  so 
  striking. 
  On 
  igneous 
  fusion 
  at 
  red 
  

   heat, 
  the 
  usual 
  black 
  lead 
  glass 
  is 
  again 
  obtained. 
  As 
  to 
  hard- 
  

   ness, 
  water 
  glass 
  is 
  not 
  much 
  inferior 
  to 
  the 
  original 
  igneous 
  

   glass. 
  When 
  clear 
  it 
  has 
  a 
  different 
  refractive 
  index 
  and 
  a 
  dif- 
  

   ferent 
  density. 
  

  

  After 
  exposure 
  to 
  the 
  air 
  water 
  glass 
  gradually 
  disintegrates. 
  

   Even 
  after 
  a 
  few 
  weeks 
  cracks 
  permeate 
  the 
  mass, 
  and 
  the 
  

   originally 
  solid 
  tough 
  block 
  may 
  easily 
  be 
  broken 
  across. 
  I 
  

   have 
  supposed 
  that 
  the 
  combination 
  of 
  water 
  and 
  glass, 
  stable 
  

   under 
  pressure 
  at 
  210°, 
  is 
  unstable 
  at 
  ordinary 
  temperatures, 
  

   and 
  that 
  water 
  set 
  free 
  under 
  probably 
  immense 
  pressures 
  is 
  

   the 
  cause 
  of 
  this 
  phenomenon. 
  Inasmuch 
  as 
  the 
  fragments 
  

   retain 
  their 
  property 
  of 
  swelling 
  on 
  fusion 
  unimpaired, 
  it 
  is 
  

   much 
  more 
  probable 
  that 
  the 
  real 
  cause 
  of 
  breakage 
  is 
  the 
  

   gradual 
  reaction 
  of 
  internal 
  stress. 
  

  

  Not 
  all 
  kinds 
  of 
  glass 
  succumb 
  to 
  the 
  present 
  treatment 
  at 
  

   210 
  c 
  . 
  The 
  more 
  infusible 
  glasses 
  are 
  much 
  less 
  easily 
  soluble. 
  

   Many 
  experiments 
  of 
  the 
  present 
  kind 
  made 
  with 
  hard 
  glass 
  

   showed 
  absolutely 
  no 
  cohesion 
  or 
  fusion 
  when 
  examined 
  in 
  the 
  

   cold, 
  even 
  after 
  IS 
  hours 
  of 
  exposure. 
  Hence 
  a 
  higher 
  tem- 
  

   perature 
  than 
  2< 
  in 
  c 
  will 
  here 
  be 
  needed, 
  and 
  the 
  case 
  is 
  emphat- 
  

   ically 
  true 
  for 
  quartz. 
  Coordinating 
  the 
  present 
  experiments, 
  

   in 
  which 
  a 
  phenomenally 
  low 
  dissolving 
  temperature 
  is 
  evi- 
  

   denced, 
  with 
  the 
  results 
  obtained 
  from 
  natural 
  silicates, 
  it 
  is 
  

   clear 
  that 
  every 
  glass 
  at 
  a 
  sufficiently 
  high 
  temperature 
  must 
  

   eventually 
  show 
  complete 
  solubility 
  in 
  water. 
  

  

  Having 
  obtained 
  the 
  water 
  glass 
  in 
  the 
  above 
  form, 
  I 
  next 
  

   endeavored, 
  with 
  the 
  addition 
  of 
  more 
  water, 
  to 
  obtain 
  the 
  

   glass 
  in 
  the 
  liquid 
  state 
  at 
  ordinary 
  temperatures 
  ; 
  but 
  these 
  

   experiments 
  signally 
  failed. 
  About 
  180 
  grams 
  of 
  the 
  given 
  

   water 
  glass 
  were 
  triturated, 
  mixed 
  with 
  50 
  grams 
  of 
  water, 
  

   charged 
  in 
  the 
  retort 
  and 
  heated 
  for 
  11 
  hours 
  to 
  210°. 
  On 
  

   opening 
  about 
  10 
  cub 
  cm 
  of 
  viscous 
  soapy 
  black 
  water 
  were 
  taken 
  

   out, 
  floating 
  above 
  a 
  black 
  scum 
  of 
  glass. 
  The 
  substance 
  when 
  

   dry 
  was 
  friable 
  and 
  had 
  lost 
  the 
  property 
  of 
  fusing 
  with 
  swell- 
  

  

  