﻿NEW 
  METALS 
  AND 
  NEW 
  METHODS 
  — 
  DESCH 
  217 
  

  

  Bridge 
  was 
  designed 
  to 
  take 
  advantage 
  of 
  the 
  high 
  tensile 
  strength 
  

   of 
  nickel 
  steel, 
  the 
  designers 
  considering 
  that 
  the 
  Forth 
  Bridge, 
  a 
  very 
  

   stable 
  structure, 
  was 
  unnecessarily 
  heavy. 
  The 
  disaster 
  of 
  1907, 
  when 
  

   the 
  unfinished 
  bridge 
  collapsed, 
  was 
  due 
  to 
  the 
  crumpling 
  of 
  the 
  lower 
  

   members, 
  although 
  calculation 
  had 
  shown 
  that 
  the 
  direct 
  load-carry- 
  

   ing 
  capacity 
  was 
  ample. 
  It 
  has 
  been 
  proposed 
  to 
  use 
  alloys 
  of 
  

   aluminum 
  on 
  a 
  large 
  scale 
  in 
  shipbuilding, 
  their 
  use 
  in 
  small 
  vessels 
  

   having 
  proved 
  successful, 
  while 
  the 
  particular 
  alloys 
  used 
  — 
  those 
  with 
  

   magnesium 
  — 
  are 
  highly 
  resistant 
  to 
  corrosion 
  by 
  sea 
  water. 
  In 
  chang- 
  

   ing 
  from 
  steel 
  to 
  light 
  alloy, 
  however, 
  it 
  would 
  not 
  be 
  enough 
  to 
  

   calculate 
  the 
  dimensions 
  of 
  each 
  member 
  to 
  give 
  a 
  strength 
  equal 
  to 
  

   that 
  in 
  a 
  steel 
  ship. 
  The 
  hull 
  would 
  float 
  too 
  high 
  in 
  the 
  water, 
  and 
  

   problems 
  of 
  stiffness 
  would 
  arise 
  from 
  the 
  very 
  different 
  elastic 
  prop- 
  

   erties; 
  to 
  build 
  a 
  successful 
  vessel 
  the 
  design 
  would 
  have 
  to 
  be 
  new 
  

   from 
  the 
  beginning. 
  

  

  So, 
  when 
  the 
  hard 
  carbide 
  steels 
  were 
  introduced 
  to 
  take 
  the 
  place 
  

   of 
  tool 
  steels 
  for 
  very 
  heavy 
  work 
  or 
  large 
  output, 
  allowing 
  cuts 
  to 
  be 
  

   made 
  on 
  a 
  lathe 
  at 
  much 
  higher 
  speeds 
  than 
  before, 
  advantage 
  of 
  the 
  

   improved 
  properties 
  could 
  not 
  be 
  taken 
  until 
  the 
  machines 
  themselves 
  

   had 
  been 
  completely 
  redesigned 
  to 
  allow 
  of 
  such 
  high 
  speeds 
  without 
  

   undue 
  vibration; 
  and 
  in 
  fact 
  the 
  introduction 
  of 
  carbide 
  tools 
  has 
  

   meant 
  a 
  revolution 
  in 
  the 
  machine-tool 
  industry, 
  much 
  plant 
  intended 
  

   for 
  large 
  outputs 
  being 
  rendered 
  obsolete. 
  

  

  Three 
  examples 
  may 
  be 
  given 
  of 
  the 
  substitution 
  of 
  an 
  entirely 
  new 
  

   material 
  for 
  one 
  of 
  which 
  the 
  supplies 
  have 
  been 
  found 
  to 
  be 
  in- 
  

   adequate 
  or 
  too 
  costly. 
  Platinum, 
  a 
  metal 
  of 
  very 
  local 
  occurrence, 
  

   has 
  been 
  largely 
  replaced 
  for 
  chemical 
  purposes, 
  fused 
  silica 
  taking 
  

   its 
  place 
  in 
  the 
  concentration 
  of 
  sulfuric 
  acid, 
  and 
  iron 
  oxide 
  in 
  various 
  

   catalytic 
  processes. 
  On 
  a 
  larger 
  scale, 
  Chile 
  nitrate, 
  a 
  product 
  formed 
  

   under 
  quite 
  exceptional 
  climatic 
  conditions 
  and 
  almost 
  unique, 
  is 
  no 
  

   longer 
  indispensable 
  as 
  a 
  fertilizer, 
  the 
  nitrogen 
  compounds 
  required 
  

   for 
  agriculture 
  and 
  explosives 
  being 
  obtained 
  synthetically 
  from 
  the 
  

   air. 
  The 
  third 
  example 
  is 
  the 
  introduction 
  of 
  plastics, 
  resinlike 
  sub- 
  

   stances 
  which 
  may 
  be 
  given 
  the 
  most 
  varied 
  properties. 
  For 
  many 
  

   purposes 
  they 
  replace 
  metals, 
  and 
  when 
  reinforced 
  by 
  textile 
  material 
  

   or 
  paper 
  have 
  a 
  strength 
  comparable 
  with 
  that 
  of 
  a 
  metal. 
  Trans- 
  

   parent 
  varieties 
  replace 
  glass 
  and 
  are 
  far 
  less 
  brittle 
  ; 
  other 
  types 
  take 
  

   the 
  place 
  of 
  porcelain 
  and 
  earthenware. 
  The 
  manufacture 
  of 
  plastics 
  

   is 
  one 
  of 
  the 
  rapidly 
  growing 
  industries, 
  and 
  the 
  uses 
  of 
  these 
  new 
  

   materials 
  are 
  continually 
  being 
  multiplied. 
  

  

  It 
  must 
  be 
  realized 
  that 
  even 
  such 
  substitutions 
  as 
  these 
  do 
  not 
  

   necessarily 
  lessen 
  our 
  dependence 
  on 
  mineral 
  resources, 
  although 
  the 
  

   relative 
  importance 
  of 
  different 
  deposits 
  may 
  be 
  altered. 
  Nitrogen 
  

   compounds 
  are 
  obtained 
  by 
  the 
  use 
  of 
  electric 
  power, 
  which 
  in 
  some 
  

  

  