﻿130 
  

  

  T. 
  A. 
  Jag 
  gar, 
  Jr. 
  — 
  Simple 
  Instrument 
  for 
  

  

  simply 
  a 
  clip 
  (e) 
  for 
  the 
  object-glass, 
  supported 
  15 
  mm 
  above 
  the 
  

   surface 
  of 
  the 
  stage 
  by 
  a 
  ball-and-socket 
  joint 
  (5); 
  a 
  long 
  key 
  

   (k), 
  fitting 
  a 
  triangular 
  aperture 
  (A) 
  in 
  the 
  clip-arm 
  (a) 
  from 
  

  

  Figure 
  I 
  (natural 
  scale). 
  

  

  either 
  side, 
  secures 
  delicacy 
  of 
  manipulation 
  and 
  enables 
  the 
  

   operator 
  to 
  incline 
  his 
  preparation 
  in 
  any 
  direction 
  by 
  a 
  simple 
  

   movement 
  of 
  the 
  fingers. 
  A 
  thumb-screw 
  (s) 
  in 
  the 
  end 
  of 
  

   the 
  barrel 
  (t) 
  that 
  serves 
  for 
  ball 
  socket, 
  permits 
  adjustment 
  of 
  

   the 
  tension 
  on 
  the 
  ball 
  by 
  pressure 
  on 
  a 
  brass 
  plate 
  (jp) 
  faced 
  

   with 
  cork, 
  which 
  fits 
  the 
  surface 
  of 
  the 
  ball.* 
  In 
  the 
  model 
  

   figured, 
  the 
  foot-ring 
  (r) 
  fits 
  the 
  center 
  of 
  the 
  Fuess 
  mechan- 
  

   ical 
  stage, 
  and 
  the 
  rectangular 
  movements 
  of 
  the 
  latter 
  allow 
  

   ample 
  horizontal 
  adjustment, 
  for 
  bringing 
  different 
  portions 
  of 
  

   the 
  section 
  into 
  the 
  visual 
  field. 
  The 
  foot 
  of 
  the 
  new 
  model 
  

   (fig. 
  2, 
  see 
  footnote 
  p. 
  129) 
  is 
  made 
  adjustable 
  to 
  the 
  clip-holes 
  

   of 
  any 
  stage, 
  and 
  the 
  elevated 
  clip 
  attached 
  to 
  the 
  ball-and-socket 
  

   is 
  of 
  such-form 
  that 
  free 
  horizontal 
  movement 
  of 
  the 
  object- 
  

   glass 
  by 
  hand 
  is 
  possible 
  in 
  all 
  directions 
  ; 
  furthermore, 
  the 
  foot- 
  

   plate 
  is 
  so 
  shaped 
  that 
  in 
  special 
  cases 
  it 
  may 
  be 
  simply 
  slipped 
  

   under 
  the 
  ordinary 
  clips, 
  and 
  thus 
  held 
  in 
  any 
  desired 
  position. 
  

  

  * 
  This 
  arrangement 
  was 
  suggested 
  to 
  the 
  writer 
  by 
  Professor 
  Groldschmidi's 
  

   two-circle 
  contact 
  goniometer, 
  where 
  the 
  crystal 
  is 
  centered 
  by 
  a 
  ball-joint 
  and 
  

   key: 
  v. 
  this 
  Journal, 
  Oct., 
  1896, 
  p. 
  285, 
  On 
  Crystal 
  Measurement 
  by 
  means 
  of 
  

   Angular 
  Coordinates, 
  and 
  on 
  the 
  use 
  of 
  the 
  Goniometer 
  with 
  two 
  Circles; 
  by 
  

   Charles 
  Palache. 
  

  

  