﻿THE 
  

  

  AMERICAN 
  JOURNAL 
  OF 
  SCIENCE 
  

  

  [THIRD 
  SERIES.] 
  

  

  Akt. 
  XXXI 
  Y. 
  — 
  The 
  Solution 
  of 
  Vulcanized 
  India 
  Rubber 
  ; 
  

   by 
  Carl 
  Barus. 
  

  

  1. 
  Introductory. 
  — 
  In 
  my 
  work* 
  on 
  the 
  solubility 
  of 
  glass 
  

   in 
  water, 
  I 
  showed 
  that 
  in 
  proportion 
  as 
  the 
  state 
  of 
  dissocia- 
  

   tion 
  or 
  the 
  molecular 
  instability 
  of 
  glass 
  is 
  increased 
  with 
  rise 
  

   of 
  temperature, 
  the 
  solvent 
  action 
  of 
  water 
  increases 
  at 
  an 
  

   enormously 
  rapid 
  rate 
  ; 
  that 
  inasmuch 
  as 
  the 
  solution 
  takes 
  

   place 
  between 
  a 
  solid 
  and 
  a 
  liquid, 
  sufficient 
  pressure 
  must 
  be 
  

   applied 
  to 
  keep 
  the 
  fluid 
  in 
  the 
  liquid 
  state, 
  whenever 
  the 
  

   vapor 
  tension 
  at 
  the 
  temperature 
  in 
  question 
  exceeds 
  the 
  

   atmospheric 
  pressure. 
  Thus, 
  at 
  100°, 
  the 
  action 
  of 
  liquid 
  water 
  

   on 
  glass 
  is 
  nearly 
  negligible 
  ; 
  but 
  even 
  at 
  185° 
  solution 
  occurs 
  

   at 
  so 
  rapid 
  a 
  rate 
  that 
  capillary 
  tubes 
  may 
  become 
  filled 
  with 
  

   solid 
  hyclrated 
  silicate, 
  in 
  place 
  of 
  water, 
  in 
  an 
  hour. 
  Here, 
  

   however, 
  about 
  10 
  atm. 
  must 
  be 
  applied 
  to 
  keep 
  the 
  solvent 
  in 
  

   the 
  liquid 
  state 
  essential 
  to 
  speedy 
  reaction. 
  

  

  2. 
  The 
  present 
  application. 
  — 
  Having 
  attempted 
  to 
  apply 
  the 
  

   same 
  principle 
  to 
  the 
  actual 
  solution 
  of 
  vulcanized 
  India 
  rub- 
  

   ber, 
  I 
  obtained 
  confirmatory 
  results 
  at 
  once. 
  To 
  my 
  knowl- 
  

   edge 
  this 
  material 
  has 
  not 
  heretofore 
  been 
  advantageously 
  dis- 
  

   solved 
  in 
  a 
  volatile 
  reagent, 
  or 
  in 
  any 
  reagent 
  by 
  which 
  it 
  is 
  

   speedily 
  and 
  copiously 
  taken 
  into 
  solution, 
  and 
  from 
  which 
  it 
  

   may 
  be 
  conveniently 
  obtained. 
  Cf. 
  §4, 
  note. 
  

  

  It 
  follows 
  by 
  analogy 
  from 
  § 
  1, 
  that 
  the 
  rubber 
  must 
  be 
  hot 
  

   enough 
  to 
  be 
  in 
  a 
  state 
  of 
  dissociation, 
  i. 
  e., 
  that 
  the 
  coherence 
  

   of 
  the 
  rubber-sulphur 
  molecules 
  must 
  show 
  an 
  instability 
  in 
  

   regard 
  to 
  whatever 
  solvent 
  may 
  be 
  used. 
  It 
  follows, 
  more- 
  

  

  * 
  This 
  Jour., 
  xxxviii, 
  p. 
  408, 
  1889. 
  Ibid, 
  xli, 
  p. 
  ] 
  10, 
  1891. 
  

  

  Am. 
  Jour. 
  Sci. 
  — 
  Third 
  Series, 
  Vol. 
  XLII, 
  No. 
  251. 
  — 
  November. 
  1891. 
  

   25 
  

  

  