﻿288 
  JOURNAL 
  OF 
  THE 
  WASHINGTON 
  ACADEMY 
  OF 
  SCIENCES 
  VOL. 
  12, 
  NO. 
  12 
  

  

  The 
  first 
  lighthouse 
  in 
  this 
  country 
  was 
  built 
  by 
  Massachusetts 
  at 
  

   Boston, 
  in 
  1716, 
  and 
  this 
  station 
  is 
  still 
  in 
  operation. 
  Several 
  other 
  

   lighthouses 
  were 
  built 
  by 
  the 
  colonies. 
  The 
  maintenance 
  of 
  the 
  

   lighthouse 
  system 
  was 
  the 
  first 
  public 
  work, 
  or 
  work 
  of 
  a 
  technical 
  

   character, 
  undertaken 
  by 
  the 
  United 
  States 
  Government, 
  being 
  pro- 
  

   vided 
  for 
  at 
  the 
  first 
  session 
  of 
  Congress 
  in 
  1789. 
  

  

  CRYSTALLOGRAPHY. 
  — 
  Crystallographic-optical 
  properties 
  of 
  cal- 
  

   cium 
  Jumar 
  ate 
  and 
  maleate} 
  Edgar 
  T. 
  Wherry 
  and 
  Raymond 
  

   M. 
  Hann, 
  Bureau 
  of 
  Chemistry. 
  

  

  Crystals 
  of 
  these 
  salts 
  do 
  not 
  appear 
  to 
  have 
  been 
  measured 
  here- 
  

   tofore. 
  They 
  are, 
  however, 
  of 
  interest 
  in 
  that 
  the 
  acids 
  represent 
  a 
  

   simple 
  case 
  of 
  stereoisomerism, 
  so 
  we 
  have 
  prepared 
  them 
  and 
  studied 
  

   them 
  in 
  detail. 
  

  

  CALCIUM 
  FUMARATE, 
  Ca(C4H204) 
  . 
  2H2O 
  

  

  Preparation. 
  — 
  The 
  fumaric 
  acid 
  was 
  obtained 
  from 
  a 
  commercial 
  

   firm 
  now 
  making 
  it 
  in 
  a 
  high 
  state 
  of 
  purity 
  by 
  a 
  catalytic 
  process. 
  

   After 
  several 
  trials 
  the 
  following 
  plan 
  was 
  found 
  to 
  yield 
  the 
  best 
  

   crystals 
  of 
  the 
  calcium 
  salt: 
  Dissolve 
  2V2 
  grams 
  of 
  fumaric 
  acid 
  in 
  

   50 
  cc. 
  of 
  water, 
  heat 
  to 
  boiling, 
  neutralize 
  with 
  30% 
  KOH 
  solution, 
  

   and 
  then 
  acidify 
  slightly 
  by 
  the 
  addition 
  of 
  a 
  small 
  amount 
  of 
  the 
  acid. 
  

   To 
  the 
  boiling 
  solution 
  add 
  an 
  equal 
  volume 
  of 
  5% 
  CaCl2 
  solution 
  and 
  

   continue 
  boiling 
  until 
  a 
  slight 
  turbidity 
  appears. 
  Filter 
  the 
  solution, 
  

   cover 
  loosely 
  and 
  allow 
  to 
  stand 
  for 
  several 
  weeks. 
  Groups 
  of 
  blade- 
  

   like 
  crystals 
  as 
  much 
  as 
  2 
  mm. 
  in 
  length 
  then 
  separate 
  out. 
  Before 
  

   removing 
  them 
  for 
  study 
  the 
  solution 
  is 
  best 
  placed 
  in 
  a 
  cold 
  place 
  for 
  

   a 
  time 
  to 
  cause 
  the 
  crystals 
  to 
  take 
  up 
  material 
  and 
  repair 
  any 
  corro- 
  

   sion 
  which 
  their 
  faces 
  may 
  have 
  suffered. 
  

  

  Composition. 
  — 
  -On 
  ignition 
  the 
  salt 
  was 
  found 
  to 
  yield 
  a 
  residue 
  of 
  

   CaO 
  equivalent 
  to 
  28.47%, 
  indicating 
  the 
  presence 
  of 
  2 
  molecules 
  of 
  

   water 
  of 
  crystallization 
  (theory, 
  29.5%). 
  

  

  Crystallography 
  . 
  — 
  -It 
  was 
  found 
  that 
  where 
  crystals 
  lay 
  close 
  to- 
  

   gether 
  in 
  groups 
  their 
  angles 
  were 
  somewhat 
  distorted, 
  but 
  it 
  was 
  pos- 
  

   sible 
  to 
  pick 
  out 
  several 
  fairly 
  free 
  from 
  such 
  disturbances, 
  and 
  five 
  

   of 
  these 
  were 
  submitted 
  to 
  crystallographic 
  measurement. 
  They 
  are 
  

   orthorhombic 
  and 
  tabular 
  on 
  a 
  pinacoid, 
  with 
  marginal 
  dome-prism 
  

   forms. 
  

  

  In 
  an 
  orthorhombic 
  crystal 
  a 
  choice 
  of 
  six 
  orientations 
  is 
  open 
  to 
  the 
  

  

  ^ 
  Contribution 
  from 
  the 
  Analytical 
  Reagents 
  Investigation 
  Laboratory 
  and 
  Laboratory 
  

   of 
  Crystallographer. 
  Received 
  May 
  20, 
  1922. 
  

  

  