﻿160 
  Mr. 
  Hollo 
  Appleyard 
  on 
  the 
  Failure 
  of 
  

  

  San 
  Juan 
  del 
  Sur 
  during 
  the 
  same 
  time. 
  Both 
  towns 
  are 
  

   within 
  about 
  10 
  degrees 
  of 
  latitude 
  of 
  the 
  equator. 
  

  

  (7) 
  In 
  September 
  1895 
  similar 
  bobbins 
  were 
  shipped 
  

   to 
  Panama. 
  The 
  wire 
  of 
  one 
  was 
  reported 
  " 
  broken 
  " 
  in 
  

   November 
  1896. 
  

  

  (8) 
  Between 
  October 
  1894 
  and 
  September 
  1895 
  about 
  a 
  

   thousand 
  bobbins 
  of 
  platinoid 
  wire, 
  made 
  and 
  protected 
  as 
  

   above 
  described, 
  treated 
  with 
  paraffin-wax 
  and 
  sheathed 
  with 
  

   ebonite, 
  were 
  shipped 
  to 
  Pernambuco, 
  Rio 
  Janeiro, 
  and 
  

   Salina 
  Cruz. 
  No 
  reports 
  of 
  failure 
  have, 
  so 
  far, 
  been 
  received 
  

   from 
  these 
  towns. 
  They 
  are 
  all 
  within 
  the 
  tropics. 
  

  

  (9) 
  In 
  March 
  1895 
  a 
  voltmeter, 
  wound 
  with 
  silk-covered 
  

   german-silver 
  wire, 
  was 
  shipped 
  to 
  Calcutta. 
  The 
  wire 
  was 
  

   not 
  treated 
  with 
  paraffin-wax, 
  and 
  no 
  ebonite 
  was 
  used 
  in 
  

   connexion 
  with 
  it. 
  In 
  February 
  1897 
  every 
  inch 
  of 
  the 
  wire 
  

   was 
  rotten. 
  As 
  the 
  coil 
  was 
  unwound, 
  the 
  wire 
  fell 
  to 
  pieces. 
  

   Slight 
  electrical 
  heating 
  had 
  possibly 
  accelerated 
  the 
  structural 
  

   change 
  of 
  the 
  alloy. 
  

  

  (10) 
  The 
  specimens 
  of 
  various 
  german-silver 
  and 
  platinoid 
  

   wires 
  on 
  bobbins 
  kept 
  in 
  England 
  are 
  still 
  quite 
  good. 
  This 
  

   applies 
  to 
  the 
  wire 
  such 
  as 
  was 
  used 
  for 
  the 
  voltmeter, 
  as 
  well 
  

   as 
  to 
  the 
  platinoid 
  such 
  as 
  was 
  used 
  for 
  the 
  resistance-coils. 
  

   This 
  autumn 
  I 
  selected 
  some 
  of 
  these 
  home-specimens 
  and 
  

   formed 
  them 
  into 
  small 
  coils. 
  They 
  were 
  then 
  exposed 
  just 
  

   above 
  the 
  surface 
  of 
  a 
  tank 
  of 
  water 
  that 
  was 
  boiled 
  all 
  day 
  

   and 
  allowed 
  to 
  cool 
  all 
  night. 
  This 
  process 
  was 
  continued 
  

   for 
  six 
  weeks 
  with 
  no 
  apparent 
  deteriorating 
  effect 
  upon 
  any 
  

   of 
  the 
  coils. 
  

  

  (11) 
  A 
  piece 
  of 
  bare 
  platinoid 
  wire 
  kept 
  for 
  some 
  years 
  in 
  

   the 
  laboratory 
  has 
  become 
  discoloured, 
  and 
  there 
  are 
  several 
  

   black 
  spots 
  in 
  it 
  ; 
  but 
  I 
  can 
  find 
  no 
  " 
  short 
  " 
  places 
  and 
  no 
  

   mechanical 
  weakness 
  anywhere. 
  

  

  (12) 
  Some 
  suspended 
  helices 
  of 
  bare 
  german-silver 
  wire 
  

   have 
  broken 
  in 
  several 
  places 
  ; 
  these 
  have 
  had 
  current 
  through 
  

   them 
  from 
  time 
  to 
  time. 
  One 
  of 
  the 
  fractures 
  occurred 
  at 
  or 
  

   very 
  near 
  a 
  brazed 
  joint. 
  The 
  helices 
  were 
  under 
  slight 
  

   torsional 
  stress. 
  There 
  were 
  no 
  fractures 
  in 
  the 
  short 
  hori- 
  

   zontal 
  german-silver 
  wires 
  connecting 
  these 
  helices. 
  

  

  The 
  constitution 
  of 
  german-silver 
  is 
  stated 
  to 
  vary 
  as 
  

   follows 
  : 
  — 
  

  

  Copper 
  50-66 
  parts. 
  

  

  Zinc 
  19-31 
  „ 
  

  

  Nickel 
  13-18 
  „ 
  

  

  Platinoid 
  is 
  generally 
  described 
  as 
  german-silver 
  with 
  two 
  per 
  

   cent, 
  of 
  tungsten. 
  According 
  to 
  Brannt, 
  the 
  tungsten, 
  in 
  the 
  

  

  