﻿292 
  JOURNAL 
  OF 
  the; 
  WASHINGTON 
  ACADEMY 
  OF 
  SCIENCES 
  VOL. 
  12, 
  NO. 
  12 
  

  

  rapidly 
  cooling 
  crystals 
  had 
  a 
  series 
  of 
  steep 
  domes 
  forming 
  a 
  more 
  or 
  

   less 
  continuous 
  curve, 
  while 
  those 
  that 
  cooled 
  more 
  slowly 
  had 
  but 
  a 
  

   single 
  flat 
  dome. 
  The 
  system, 
  as 
  with 
  the 
  fumarate, 
  is 
  orthorhombic. 
  

   -. 
  In 
  standard 
  orientation, 
  placing 
  the 
  direction 
  of 
  elongation 
  vertical 
  

   and 
  the 
  pinacoid 
  at 
  the 
  side, 
  the 
  angles 
  of 
  Table 
  3 
  are 
  obtained. 
  

  

  TABLE 
  3. 
  — 
  Angles 
  of 
  calcium 
  maleate 
  in 
  standard 
  orientation 
  

  

  Orthorhombic; 
  a 
  : 
  h 
  : 
  c 
  = 
  0.779 
  : 
  1 
  : 
  0.643 
  (po 
  = 
  0.825; 
  qo 
  = 
  0.643). 
  

  

  Angles 
  Observed 
  

  

  Description 
  ^ 
  p 
  

  

  Narrow 
  and 
  sometimes 
  lacking 
  0°00' 
  90°00' 
  

  

  Dominant 
  form 
  52 
  °05 
  ' 
  90 
  °00 
  ' 
  

  

  Principal 
  termination 
  °00 
  ' 
  32 
  °45 
  ' 
  

  

  Part 
  of 
  long 
  curved 
  form 
  0°00' 
  76° 
  ± 
  

  

  Part 
  of 
  long 
  curved 
  form 
  0°00' 
  79°="= 
  

  

  This 
  is 
  close 
  to 
  the 
  mineral 
  chalcostibite 
  (wolfsbergite), 
  CuSbS2, 
  

   which 
  has 
  a 
  : 
  b 
  : 
  c 
  = 
  0.8026 
  : 
  1 
  : 
  0.6275. 
  

  

  In 
  this 
  case 
  as 
  before 
  the 
  standard 
  orientation 
  is 
  not 
  the 
  significant 
  

   one, 
  for 
  the 
  prism 
  angle 
  is 
  over 
  7° 
  away 
  from 
  the 
  theory 
  for 
  the 
  tet- 
  

   ragonal, 
  while 
  the 
  principal 
  dome 
  has 
  a 
  phi 
  angle 
  less 
  than 
  3° 
  away 
  

   from 
  the 
  theory 
  for 
  a 
  more 
  symmetrical 
  system, 
  in 
  this 
  case 
  the 
  hexag- 
  

   onal. 
  Turning 
  the 
  pinacoid 
  to 
  the 
  front, 
  in 
  order 
  to 
  make 
  axis 
  h 
  

   the 
  shortest 
  one, 
  this 
  gives 
  the 
  angles 
  and 
  axial 
  values 
  of 
  Table 
  4 
  and 
  

   Figure 
  1. 
  

  

  TABLE 
  4. 
  — 
  Angles 
  of 
  calcium 
  malEate 
  in 
  significant 
  orientation 
  

   Orthorhombic; 
  a 
  : 
  b 
  : 
  c 
  = 
  1.555 
  : 
  1 
  : 
  1.211 
  (pn 
  = 
  0.779; 
  qo 
  = 
  1.211). 
  Peri- 
  

   hexagonal, 
  with 
  deviation 
  of 
  prism 
  angle 
  tp 
  from 
  theory 
  for 
  hexagonal 
  2 
  °45'. 
  

  

  Space 
  relations. 
  — 
  Calculating 
  the 
  unit-volume 
  axes 
  as 
  before, 
  the 
  

   results 
  are: 
  A 
  : 
  5 
  : 
  C 
  = 
  1 
  .259 
  : 
  0.810 
  : 
  0.981. 
  The 
  specific 
  gravity 
  

   determined 
  by 
  the 
  same 
  method 
  as 
  in 
  the 
  preceding 
  case, 
  was 
  de- 
  

   cidedly 
  greater, 
  1 
  . 
  84 
  =i= 
  0.01. 
  The 
  molecular 
  weight 
  being 
  172 
  . 
  1, 
  this 
  

   gives 
  the 
  molecular 
  volume 
  93 
  . 
  5 
  and 
  its 
  cube 
  root 
  4 
  . 
  54, 
  making 
  the 
  

   topic 
  axes 
  x 
  : 
  'A 
  : 
  <^ 
  = 
  5.72 
  : 
  3.68 
  : 
  4.45. 
  No 
  relation 
  can 
  be 
  traced 
  

   with 
  the 
  corresponding 
  values 
  for 
  the 
  fumarate. 
  

  

  Optical 
  properties. 
  — 
  Calcium 
  maleate 
  is 
  like 
  the 
  fumarate 
  biaxial 
  

   and 
  negative, 
  but 
  its 
  refractive 
  indices 
  are 
  much 
  higher 
  and 
  the 
  double 
  

  

  