﻿210 
  

  

  Mr. 
  R. 
  Mallet 
  on 
  the 
  alleged 
  Expansion 
  

  

  Iron 
  and 
  Furnace-slags, 
  by 
  experiment 
  of 
  Heunter 
  and 
  Snelus, 
  as 
  

   quoted 
  by 
  Nasmyth 
  and 
  Carpenter. 
  

  

  But 
  of 
  this 
  list 
  the 
  only 
  body, 
  in 
  addition 
  to 
  water, 
  that 
  really 
  appears 
  

   proved 
  to 
  expand 
  in 
  consolidating 
  is 
  bismuth 
  ; 
  and 
  even 
  this 
  the 
  author 
  

   cannot 
  affirm 
  upon 
  the 
  basis 
  of 
  his 
  own 
  experiments, 
  but 
  accepts 
  the 
  fact, 
  

   at 
  least 
  provisionally, 
  as 
  true 
  upon 
  the 
  uncontradicted 
  statements 
  of 
  many 
  

   chemical 
  authors, 
  and 
  upon 
  the 
  positive 
  assurance 
  which 
  he 
  is 
  permitted 
  

   to 
  mention 
  by 
  Dr. 
  John 
  Tyndall 
  that 
  he 
  is 
  satisfied 
  of 
  its 
  truth. 
  "With 
  

   respect 
  to 
  all 
  the 
  others, 
  it 
  is 
  the 
  object 
  of 
  this 
  communication 
  to 
  show 
  

   that 
  the 
  evidence 
  in 
  support 
  of 
  the 
  alleged 
  fact 
  of 
  expansion 
  by 
  refrige- 
  

   ration 
  is 
  illusory 
  and 
  insufficient, 
  and 
  to 
  offer 
  with 
  respect 
  to 
  cast 
  iron, 
  

   and 
  also 
  with 
  respect 
  to 
  iron 
  furnace-slags, 
  experimental 
  proof 
  of 
  the 
  

   untruth 
  of 
  the 
  statement. 
  

  

  Certain 
  connected 
  but 
  only 
  collateral 
  facts, 
  having 
  regard 
  to 
  so-called 
  

   anomalous 
  changes 
  of 
  volume 
  due 
  to 
  temperature, 
  will 
  not 
  be 
  referred 
  to 
  

   here 
  — 
  such, 
  for 
  example, 
  as 
  the 
  anomalous 
  expansion 
  of 
  Rose's 
  fusible 
  

   metal, 
  which 
  expands 
  progressively, 
  like 
  other 
  bodies, 
  till 
  it 
  attains 
  the 
  

   temperature 
  of 
  111° 
  ; 
  it 
  then 
  contracts 
  rapidly 
  by 
  added 
  heat 
  to 
  150°, 
  when 
  

   it 
  is 
  densest 
  (Graham's 
  ' 
  Elements,' 
  vol. 
  i., 
  and 
  Grmelin's 
  'Handbook 
  '), 
  the 
  

   circumstances 
  being 
  here 
  probably 
  due 
  to 
  the 
  successive 
  segregation 
  in 
  

   the 
  mass 
  of 
  alloys 
  differing 
  from 
  each 
  other 
  in 
  constitution, 
  dilatability, 
  

   and 
  fusing-points. 
  Or, 
  again, 
  the 
  facts 
  observed 
  with 
  respect 
  to 
  the 
  ex- 
  

   pansion 
  or 
  contraction 
  in 
  volume 
  shown 
  by 
  certain 
  salts 
  when 
  crystallizing 
  

   from 
  their 
  solutions, 
  the 
  whole 
  of 
  the 
  conditions 
  as 
  to 
  which 
  have 
  not 
  

   been 
  as 
  yet 
  made 
  quite 
  clear. 
  The 
  statement 
  that 
  a.ntimony 
  expands 
  in 
  

   consolidating, 
  as 
  made 
  by 
  Reaumur, 
  has 
  been 
  negatived 
  by 
  Marx. 
  The 
  

   like 
  statement 
  with 
  respect 
  to 
  silver 
  and 
  copper 
  appears 
  to 
  rest 
  on 
  no 
  

   better 
  foundation 
  than 
  the 
  observation 
  as 
  stated 
  by 
  Persoz, 
  " 
  that 
  pieces 
  

   of 
  solid 
  silver 
  float 
  upon 
  the 
  melted 
  metal, 
  showing 
  that 
  silver 
  expands 
  

   in 
  solidifying 
  like 
  water 
  " 
  (Grmelin's 
  ' 
  Handbook,' 
  vol. 
  vi,). 
  As 
  to 
  gold, 
  

   there 
  appears 
  no 
  authority 
  whatever 
  for 
  its 
  expansion 
  on 
  consolidation. 
  

   Mr. 
  Nasmyth 
  has 
  included 
  it 
  in 
  his 
  catalogue 
  merely 
  on 
  the 
  vague 
  in- 
  

   ference 
  that, 
  like 
  silver 
  and 
  copper, 
  it 
  " 
  exhibits 
  surface-converging 
  cur- 
  

   rents 
  in 
  the 
  melting-pot 
  like 
  those 
  depicted 
  by 
  him 
  for 
  molten 
  iron 
  " 
  (' 
  The 
  

   Moon,' 
  Nasmyth 
  and 
  Carpenter, 
  p. 
  24), 
  which, 
  as 
  we 
  shall 
  see 
  further 
  

   on, 
  affords 
  no 
  grounds 
  for 
  conclusion 
  on 
  the 
  matter. 
  Reaumur's 
  state- 
  

   ment 
  with 
  respect 
  to 
  cast 
  iron 
  appears 
  to 
  have 
  rested 
  upon 
  nothing 
  more 
  

   than 
  the 
  fact 
  that 
  he 
  had 
  observed 
  certain 
  pieces 
  of 
  cold 
  cast 
  iron 
  to 
  float 
  

   upon 
  cast 
  iron 
  while 
  in 
  fusion. 
  Until 
  lately 
  this 
  subject 
  generally 
  at- 
  

   tracted 
  but 
  little 
  attention, 
  for 
  it 
  had 
  very 
  few, 
  and 
  these 
  mere 
  technical, 
  

   applications 
  ; 
  and 
  to 
  the 
  higher 
  physicist 
  they 
  presented 
  but 
  little 
  interest, 
  

   because 
  the 
  loosely 
  stated 
  facts, 
  even 
  if 
  accredited, 
  did 
  not 
  in 
  the 
  slightest 
  

   degree 
  tend 
  to 
  elucidate 
  or 
  explain 
  the 
  remarkable 
  and 
  perhaps 
  still 
  iso- 
  

   lated 
  facts 
  as 
  to 
  water 
  and 
  ice. 
  Accordingly, 
  with 
  little 
  or 
  no 
  exami- 
  

   nation, 
  the 
  statements 
  given 
  for 
  facts 
  by 
  the 
  older 
  authorities 
  have 
  been 
  

  

  