﻿356 
  Messrs. 
  De 
  La 
  Rue, 
  Miiller, 
  and 
  Spottiswoode 
  on 
  [Apr. 
  8, 
  

  

  and 
  Rhytiphloea 
  Gomardii 
  are 
  amongst 
  the 
  novelties. 
  A 
  large 
  number 
  of 
  

   zoological 
  and 
  botanical 
  specimens 
  have 
  been 
  lost 
  through 
  my 
  inability 
  

   to 
  attend 
  to 
  them 
  in 
  time 
  without 
  assistance. 
  This 
  has 
  principally 
  

   affected 
  the 
  number 
  of 
  duplicates 
  ; 
  but 
  in 
  one 
  instance 
  it 
  has 
  led 
  to 
  the 
  

   loss 
  of 
  a 
  species 
  — 
  one 
  of 
  the 
  Petrels, 
  which 
  was 
  the 
  commonest 
  bird 
  

   about 
  here 
  when 
  we 
  first 
  arrived. 
  Fortunately 
  it 
  is 
  a 
  well-known 
  species. 
  

  

  The 
  1st 
  of 
  March 
  is 
  announced 
  as 
  the 
  approximate 
  date 
  of 
  our 
  sailing 
  

   from 
  Kerguelen's 
  Island. 
  Five 
  weeks 
  later 
  I 
  hope 
  to 
  arrive 
  at 
  the 
  Cape 
  

   and 
  to 
  forward 
  to 
  you 
  such 
  of 
  the 
  specimens 
  collected 
  as 
  require 
  only 
  

   ordinary 
  care 
  in 
  their 
  transmission. 
  The 
  more 
  fragile 
  things 
  are 
  likely 
  to 
  

   reach 
  you 
  in 
  better 
  condition 
  if 
  I 
  keep 
  them 
  until 
  my 
  return 
  to 
  England, 
  

   than 
  they 
  would 
  if 
  they 
  were 
  sent 
  with 
  the 
  others. 
  

  

  I 
  am, 
  dear 
  Sir, 
  

  

  Faithfully 
  yours, 
  

  

  A. 
  E. 
  Eaton. 
  

  

  II. 
  "Experiments 
  to 
  ascertain 
  the 
  Cause 
  of 
  Stratification 
  in 
  

   Electrical 
  Discharges 
  in 
  vacuo." 
  By 
  Warren 
  De 
  La 
  Rue, 
  

   Hugo 
  W. 
  Muller, 
  and 
  William 
  Spottiswoode. 
  Received 
  

   February 
  24, 
  1875. 
  

  

  Some 
  results 
  obtained 
  in 
  working 
  with 
  a 
  chloride-of 
  -silver 
  battery 
  of 
  

   1080 
  cells 
  in 
  connexion 
  with 
  vacuum-tubes 
  appear 
  to 
  be 
  of 
  sufficient 
  

   interest 
  to 
  induce 
  us 
  to 
  communicate 
  them 
  to 
  the 
  Society, 
  in 
  anticipation 
  

   of 
  the 
  more 
  detailed 
  account 
  of 
  an 
  investigation 
  which 
  is 
  now 
  being 
  pro- 
  

   secuted, 
  and 
  which 
  it 
  is 
  intended 
  to 
  continue, 
  shortly, 
  with 
  a 
  battery 
  of 
  

   5000 
  cells, 
  and 
  possibly 
  with 
  a 
  far 
  greater 
  number. 
  

  

  The 
  battery 
  used 
  up 
  till 
  now 
  consists 
  of 
  1080 
  cells, 
  each 
  being 
  formed 
  of 
  

   a 
  glass 
  tube 
  6 
  inches 
  (15-23 
  centims.) 
  long 
  and 
  f 
  of 
  an 
  inch 
  (1*9 
  centim.) 
  

   internal 
  diameter; 
  these 
  are 
  closed 
  with 
  a 
  vulcanized 
  rubber 
  stopper 
  

   (cork), 
  perforated 
  eccentrically 
  to 
  permit 
  the 
  insertion 
  of 
  a 
  zinc 
  rod, 
  care- 
  

   fully 
  amalgamated, 
  T 
  3 
  g- 
  (0*48 
  centim.) 
  of 
  an 
  inch 
  in 
  diameter 
  and 
  4*5 
  inches 
  

   (11*43 
  centims.) 
  long. 
  The 
  other 
  element 
  consists 
  of 
  a 
  flattened 
  silver 
  

   wire 
  passing 
  by 
  the 
  side 
  of 
  the 
  cork 
  to 
  the 
  bottom 
  of 
  the 
  tube 
  and 
  

   covered, 
  at 
  the 
  upper 
  part 
  above 
  the 
  chloride 
  of 
  silver 
  and 
  until 
  it 
  passes 
  

   the 
  stopper, 
  with 
  thin 
  sheet 
  gutta 
  percha 
  for 
  insulation, 
  and 
  to 
  protect 
  it 
  

   from 
  the 
  action 
  of 
  the 
  sulphur 
  in 
  the 
  vulcanized 
  corks 
  ; 
  these 
  wires 
  are 
  

  

  of 
  an 
  inch 
  (0*16 
  centim.) 
  broad 
  and 
  8 
  inches 
  (20*32 
  centims.) 
  long. 
  In 
  

   the 
  bottom 
  of 
  the 
  tube 
  is 
  placed 
  225*25 
  grains 
  (14*59 
  grms.) 
  chloride 
  of 
  

   silver 
  in 
  powder 
  ; 
  this 
  constitutes 
  the 
  electrolyte 
  : 
  above 
  the 
  chloride 
  of 
  

   silver 
  is 
  poured 
  a 
  solution 
  of 
  common 
  salt 
  containing 
  25 
  grammes 
  chlo- 
  

   ride 
  of 
  sodium 
  to 
  1 
  litre 
  (1752 
  grains 
  to 
  1 
  gallon) 
  of 
  water, 
  to 
  within 
  

   about 
  1 
  inch 
  (2*54 
  centims.) 
  of 
  the 
  cork. 
  The 
  connexion 
  between 
  

   adjoining 
  cells 
  is 
  made 
  by 
  passing 
  a 
  short 
  piece 
  of 
  india-rubber 
  tube 
  

  

  