﻿E. 
  Kidwell 
  — 
  Improved 
  Rock 
  Cutter 
  and 
  Trimmer, 
  117 
  

  

  the 
  Argon, 
  unabsorbed 
  by 
  any 
  subsequent 
  reagents, 
  might 
  

   finally 
  turn 
  up 
  dissolved 
  in 
  the 
  water 
  formed 
  by 
  synthesis, 
  and 
  

   if 
  this 
  water 
  were 
  saturated 
  with 
  Argon 
  the 
  effect 
  on 
  the 
  ratio 
  

   would 
  be 
  to 
  reduce 
  it 
  from 
  1 
  : 
  16 
  to 
  1 
  : 
  15*98.* 
  

  

  Probably 
  it 
  will 
  be 
  difficult 
  to 
  handle 
  gases 
  over 
  the 
  water 
  

   bath 
  without 
  the 
  risk 
  of 
  such 
  contamination. 
  In 
  the 
  case, 
  

   however, 
  of 
  density 
  determinations 
  it 
  would 
  seem 
  advisable 
  

   after 
  the 
  weighing 
  to 
  absorb 
  the 
  gas 
  by 
  suitable 
  reagents, 
  and 
  

   then 
  if 
  any 
  residual 
  gas, 
  Argon 
  or 
  any 
  other, 
  be 
  found, 
  to 
  apply 
  

   the 
  proper 
  correction 
  to 
  the 
  weights 
  already 
  obtained 
  ; 
  I 
  believe 
  

   that 
  when 
  this 
  has 
  been 
  done 
  the 
  ratio 
  of 
  H 
  to 
  O 
  will 
  be 
  

   found 
  nearer 
  to 
  the 
  value 
  1 
  to 
  16 
  than 
  is 
  at 
  present 
  supposed. 
  

  

  It 
  would 
  be 
  interesting 
  to 
  go 
  more 
  deeply 
  into 
  the 
  question 
  

   of 
  the 
  laws 
  governing 
  the 
  masses 
  of 
  the 
  elements 
  to 
  which 
  I 
  

   have 
  barely 
  alluded, 
  and 
  to 
  which 
  I 
  have 
  given 
  attention 
  for 
  

   some 
  years 
  past, 
  but 
  this 
  paper 
  would 
  then 
  be 
  extended 
  far 
  

   beyond 
  all 
  proper 
  limits. 
  At 
  some 
  future 
  time 
  I 
  may 
  discuss 
  

   this 
  matter 
  also. 
  

  

  Art. 
  XXXIII. 
  — 
  An 
  Improved 
  Rock 
  Cutter 
  and 
  Trimmer 
  / 
  

   by 
  Edgar 
  Kidwell. 
  

  

  Over 
  a 
  year 
  ago 
  the 
  Michigan 
  Geological 
  Survey 
  required 
  

   a 
  rock 
  cutter, 
  and 
  consulted 
  me 
  regarding 
  the 
  matter. 
  I 
  there- 
  

   fore 
  designed 
  one, 
  and 
  as 
  a 
  year's 
  use 
  has 
  shown 
  this 
  cutter 
  to 
  

   be 
  fully 
  capable 
  of 
  doing 
  the 
  work 
  required 
  of 
  it, 
  a 
  detailed 
  

   description 
  may 
  be 
  of 
  value 
  to 
  those 
  having 
  need 
  of 
  a 
  similar 
  

   machine. 
  

  

  The 
  cutter 
  had 
  to 
  be 
  suitable 
  for 
  heavy 
  and 
  accurate 
  work, 
  

   hence 
  ample 
  strength 
  of 
  parts, 
  power 
  in 
  the 
  mechanism, 
  and 
  

   freedom 
  from 
  lost 
  motion 
  were 
  absolutely 
  necessary. 
  Previous 
  

   experience 
  in 
  our 
  shops 
  had 
  shown 
  me 
  that 
  a 
  So. 
  4 
  parallel 
  

   swivel 
  railway 
  chipping 
  vise, 
  with 
  wrought 
  bar, 
  as 
  made 
  by 
  

   Merrill 
  Brothers, 
  possessed 
  all 
  these 
  qualifications, 
  and 
  1 
  there- 
  

   fore 
  made 
  in 
  one 
  of 
  their 
  vises 
  such 
  changes 
  as 
  were 
  necessary 
  

   to 
  convert 
  it 
  into 
  a 
  cutter. 
  The 
  vise 
  itself 
  needed 
  but 
  few 
  

   alterations, 
  as 
  it 
  was 
  necessary 
  only 
  to 
  cut 
  away 
  the 
  jaws 
  to 
  

   give 
  the 
  operator 
  more 
  room, 
  and 
  provide 
  suitable 
  openings 
  

   for 
  inserting 
  the 
  steel 
  cutters. 
  Provision 
  was 
  also 
  made 
  for 
  

   holding 
  cutters 
  in 
  place, 
  and 
  changing 
  them 
  quickly 
  when 
  

   necessary. 
  Fig. 
  1 
  shows 
  all 
  necessary 
  details. 
  

  

  * 
  It 
  is 
  rather 
  significant 
  that 
  the 
  best 
  determinations 
  by 
  these 
  two 
  different 
  

   methods 
  closely 
  approximate 
  to 
  these 
  two 
  values 
  of 
  15-88 
  and 
  15-98 
  respectively. 
  

  

  