﻿1875.] 
  

  

  certain 
  Alloys 
  of 
  Silver 
  and 
  Copper. 
  

  

  495 
  

  

  The 
  mean 
  of 
  the 
  coefficients 
  of 
  linear 
  dilatation 
  of 
  silyer 
  between 
  0° 
  

   and 
  100° 
  0., 
  given 
  by 
  various 
  authorities, 
  is 
  

  

  0-00002015. 
  

  

  It 
  will 
  thus 
  be 
  seen 
  that 
  the 
  expansion 
  of 
  silver 
  between 
  0°.C. 
  

   and 
  1050° 
  C. 
  is 
  about 
  twice 
  as 
  much 
  as 
  it 
  would 
  have 
  been 
  had 
  this 
  

   rate 
  of 
  expansion 
  been 
  maintained 
  through 
  the 
  whole 
  range 
  of 
  tem- 
  

   perature. 
  

  

  The 
  mean 
  coefficient 
  of 
  linear 
  dilatation 
  of 
  Levol's 
  alloy, 
  as 
  deduced 
  

   from 
  the 
  results 
  given 
  in 
  the 
  Table, 
  is 
  

  

  0-00003703 
  ; 
  

  

  but 
  it 
  is 
  impossible 
  to 
  compare 
  this 
  with 
  the 
  rate 
  of 
  expansion 
  at 
  low 
  

   temperatures, 
  as 
  the 
  latter 
  has 
  not 
  been 
  ascertained. 
  

  

  

  Initial 
  

   volume 
  

   of 
  

   cone. 
  

  

  Volume 
  

   of 
  cone 
  

   filled 
  with 
  

   molten 
  

   metal. 
  

  

  Tempera- 
  

   ture 
  of 
  

   metal 
  

   when 
  

   poured. 
  

  

  Weight 
  

  

  of 
  

   metal. 
  

  

  Density 
  

   when 
  

   fluid. 
  

  

  Density 
  

   of 
  

  

  solid 
  metal. 
  

  

  Pure 
  silver. 
  

  

  c. 
  c. 
  

   536-6 
  

  

  c. 
  c. 
  

   556-3 
  

  

  oC. 
  

  

  1143 
  

  

  grms. 
  

   5255-4 
  

  

  9-4468 
  

  

  10-57 
  

  

  542-9 
  

  

  564-4 
  

  

  1223 
  

  

  5348-3 
  

  

  9-4757 
  

  

  

  9-4612 
  

  

  

  Levol's 
  alloy. 
  

  

  735-13 
  

  

  778-06 
  

  

  1020 
  

  

  7062-4 
  

  

  9-0788 
  

  

  9-9045 
  

   [Levol], 
  

   9-998 
  _ 
  

   by 
  calculation. 
  

  

  537-42 
  

  

  557-25 
  

  

  1131 
  

  

  5033-4 
  

  

  9-0321 
  

  

  

  9-0554 
  

  

  

  In 
  conclusion 
  I 
  have 
  much 
  pleasure 
  in 
  acknowledging 
  the 
  assistance 
  

   I 
  have 
  received 
  from 
  one 
  of 
  the 
  Assistant 
  Assayers, 
  Mr. 
  Edward 
  Rigg, 
  

   whose 
  cooperation 
  has 
  been 
  of 
  much 
  service 
  to 
  me 
  ; 
  and 
  I 
  must 
  also 
  

   express 
  my 
  thanks 
  to 
  Joseph 
  Groves, 
  Senior 
  Fireman, 
  who 
  aided 
  me 
  in 
  

   the 
  furnace-operations. 
  

  

  vol. 
  xxiii, 
  ; 
  2 
  Q 
  

  

  