﻿214 
  ANNUAL 
  REPORT 
  SMITHSONIAN 
  INSTITUTION, 
  1943 
  

  

  from 
  which 
  these 
  rare 
  elements 
  are 
  obtained 
  may 
  not 
  seem 
  impressive, 
  

   but 
  the 
  access 
  to 
  them 
  may 
  be 
  an 
  important 
  factor 
  in 
  the 
  capacity 
  of 
  a 
  

   country 
  to 
  produce 
  machinery 
  and 
  other 
  constructions 
  into 
  which 
  

   metals 
  enter. 
  

  

  The 
  usefulness 
  of 
  the 
  less 
  common 
  metals 
  is, 
  of 
  course, 
  not 
  confined 
  to 
  

   small 
  additions. 
  The 
  possible 
  combinations 
  of 
  metals 
  with 
  one 
  an- 
  

   other 
  are 
  virtually 
  infinite, 
  and 
  in 
  spite 
  of 
  the 
  vast 
  amount 
  of 
  research 
  

   and 
  practical 
  experience 
  in 
  this 
  field, 
  there 
  must 
  be 
  many 
  valuable 
  

   combinations 
  as 
  yet 
  undiscovered. 
  The 
  first 
  recognition, 
  partly 
  acci- 
  

   dental, 
  that 
  steel 
  could 
  be 
  made 
  to 
  resist 
  corrosion 
  by 
  incorporating 
  

   14 
  percent 
  or 
  so 
  of 
  chromium, 
  led 
  to 
  the 
  development 
  of 
  the 
  important 
  

   class 
  of 
  stainless 
  steels, 
  while 
  the 
  new 
  magnet 
  steels, 
  containing 
  alu- 
  

   minum 
  and 
  nickel, 
  and 
  in 
  their 
  later 
  forms 
  also 
  cobalt 
  and 
  copper, 
  

   have 
  brought 
  about 
  a 
  revolution 
  in 
  the 
  construction 
  of 
  electrical 
  instru- 
  

   ments 
  and 
  loudspeakers, 
  the 
  very 
  high 
  magnetic 
  concentration 
  which 
  is 
  

   possible 
  with 
  them 
  enabling 
  very 
  small 
  permanent 
  magnets 
  to 
  be 
  used. 
  

   For 
  other 
  purposes, 
  such 
  as 
  the 
  clutches 
  used 
  for 
  holding 
  work 
  in 
  mill- 
  

   ing 
  and 
  grinding 
  machines, 
  they 
  replace 
  electromagnets. 
  With 
  these 
  

   steels 
  it 
  is 
  possible 
  to 
  realize 
  the 
  image 
  of 
  Mahomet's 
  coffin 
  — 
  heavy 
  

   bars 
  floating 
  in 
  the 
  air 
  in 
  consequence 
  of 
  their 
  strong 
  magnetic! 
  

   repulsion. 
  

  

  A 
  few 
  of 
  the 
  rare 
  metals 
  find 
  applications 
  depending 
  on 
  their 
  own 
  

   peculiar 
  properties. 
  Thus 
  tungsten, 
  with 
  its 
  very 
  high 
  melting 
  point 
  

   of 
  3650° 
  C, 
  has 
  superseded 
  all 
  other 
  materials 
  for 
  the 
  filaments 
  of 
  

   electric 
  lamps. 
  The 
  invention 
  of 
  the 
  fountain 
  pen 
  called 
  for 
  an 
  ex- 
  

   ceedingly 
  hard 
  and 
  incorrodible 
  substance 
  for 
  the 
  tips 
  of 
  the 
  gold 
  

   nibs, 
  and 
  this 
  was 
  found 
  in 
  a 
  native 
  alloy 
  of 
  osmium 
  and 
  iridium. 
  

   Tantalum 
  has 
  proved 
  specially 
  suitable 
  for 
  the 
  spinnerets 
  used 
  in 
  mak- 
  

   ing 
  artificial 
  silk, 
  rhodium 
  and 
  indium 
  for 
  depositing 
  in 
  thin 
  layers 
  

   on 
  other 
  metals 
  for 
  protection 
  against 
  corrosion, 
  and 
  so 
  on. 
  The 
  non- 
  

   metal 
  selenium 
  is 
  used 
  in 
  photoelectric 
  cells. 
  Further 
  uses 
  of 
  this 
  kind 
  

   will 
  present 
  themselves 
  as 
  the 
  properties 
  of 
  the 
  less 
  common 
  elements 
  

   are 
  studied 
  more 
  completely. 
  

  

  The 
  high 
  melting 
  point 
  of 
  some 
  of 
  the 
  metals 
  has 
  led 
  to 
  research 
  in 
  

   two 
  main 
  directions. 
  On 
  one 
  hand, 
  it 
  has 
  been 
  necessary 
  to 
  devise 
  

   means 
  of 
  making 
  metals 
  compact 
  and 
  strong 
  without 
  melting 
  them; 
  

   and 
  on 
  the 
  other, 
  to 
  develop 
  new 
  materials 
  and 
  new 
  techniques 
  for 
  op- 
  

   erations 
  at 
  temperatures 
  higher 
  than 
  those 
  in 
  ordinary 
  metallurgical 
  

   furnaces. 
  Tungsten 
  cannot 
  be 
  melted 
  in 
  a 
  container 
  of 
  any 
  known 
  

   refractory 
  material. 
  The 
  powder 
  obtained 
  by 
  reducing 
  its 
  oxide 
  is 
  

   therefore 
  packed 
  into 
  the 
  form 
  of 
  bars 
  under 
  pressure 
  and 
  heated 
  elec- 
  

   trically 
  until 
  the 
  particles 
  cohere, 
  and 
  is 
  then 
  hammered 
  in 
  a 
  special 
  

   way 
  until 
  its 
  strength 
  is 
  sufficient 
  to 
  allow 
  of 
  its 
  being 
  forged 
  or 
  drawn 
  

   into 
  wire. 
  The 
  same 
  process 
  has 
  been 
  applied 
  to 
  other 
  metals, 
  and 
  a 
  

  

  