﻿Chemistry 
  and 
  Physics. 
  

  

  319 
  

  

  of 
  mercury. 
  If 
  the 
  sulphate, 
  however, 
  be 
  moist, 
  only 
  zinc 
  

   sulphate 
  crystals 
  are 
  to 
  be 
  added 
  ; 
  care 
  must, 
  however, 
  be 
  taken 
  

   that 
  these 
  occur 
  in 
  excess 
  and 
  are 
  not 
  dissolved 
  after 
  continued 
  

   standing. 
  The 
  mercury 
  must, 
  in 
  this 
  case 
  also, 
  permeate 
  the 
  

   paste 
  in 
  little 
  globules. 
  It 
  is 
  advantageous 
  to 
  crush 
  the 
  zinc 
  

   sulphate 
  crystals 
  before 
  using, 
  since 
  the 
  paste 
  can 
  then 
  be 
  better 
  

   manipulated. 
  

  

  To 
  set 
  up 
  the 
  Cell. 
  The 
  containing 
  glass 
  vessel, 
  represented 
  in 
  

   the 
  accompanying 
  figure, 
  shall 
  consist 
  of 
  two 
  limbs 
  closed 
  at 
  

   bottom 
  and 
  joined 
  above 
  to 
  a 
  common 
  neck 
  fitted 
  with 
  a 
  ground 
  

   glass 
  stopper. 
  The 
  diameter 
  of 
  the 
  limbs 
  should 
  be 
  at 
  least 
  

   2 
  cms 
  and 
  their 
  length 
  at 
  least 
  3 
  cms 
  . 
  The 
  neck 
  should 
  be 
  not 
  less 
  

   than 
  l-5 
  cms 
  in 
  diameter. 
  At 
  the 
  bottom 
  of 
  each 
  limb 
  a 
  platinum 
  

   wire 
  of 
  about 
  0*4 
  mm 
  diameter 
  is 
  sealed 
  through 
  the 
  glass. 
  

  

  To 
  set 
  up 
  the 
  cell, 
  place 
  in 
  one 
  limb 
  pure 
  mercury 
  and 
  in 
  the 
  

   other 
  hot 
  liquid 
  amalgam, 
  containing 
  90 
  parts 
  mercury 
  and 
  10 
  

   parts 
  zinc. 
  The 
  platinum 
  wires 
  at 
  the 
  bottom 
  must 
  be 
  com- 
  

  

  