﻿Erratum. 
  — 
  In 
  the 
  December 
  number 
  of 
  Volume 
  XLII 
  of 
  this 
  Journal 
  

   the 
  last 
  seven 
  lines 
  of 
  page 
  457, 
  printed 
  as 
  a 
  foot 
  note, 
  are 
  to 
  be 
  read 
  

   with 
  Experiment 
  IV; 
  the 
  five 
  lines 
  immediately 
  preceding 
  the 
  last 
  

   seven 
  belong 
  with 
  Experiment 
  VI. 
  

  

  