﻿152 
  PROCEEDINGS 
  OF 
  THE 
  CALIFORNIA 
  

  

  To 
  effect 
  tliis, 
  I 
  have 
  devised 
  a 
  three-sided, 
  hollow, 
  rectangular 
  metal 
  casing, 
  

   to 
  fit 
  over 
  the 
  graduated 
  part 
  of 
  the 
  " 
  Boston 
  rod." 
  This 
  casing 
  is 
  made 
  up 
  

   of 
  three 
  side 
  and 
  two 
  end 
  pieces 
  of 
  bell 
  metal, 
  planed 
  to 
  the 
  .thickness 
  required, 
  

   and 
  brazed 
  together. 
  After 
  all 
  mechanical 
  work 
  is 
  done 
  upon 
  it, 
  the 
  gradua- 
  

   tion 
  is 
  made 
  and 
  compared 
  with 
  the 
  same 
  standard 
  of 
  the 
  United 
  States 
  as 
  

   the 
  measures 
  of 
  length 
  are 
  compared 
  with. 
  Its 
  standard 
  length 
  is 
  therefore 
  de- 
  

   termined 
  for 
  a 
  specified 
  temperature. 
  

  

  This 
  casing 
  fits 
  over 
  the 
  front, 
  sides 
  and 
  ends 
  of 
  the 
  front 
  part 
  of 
  the 
  or- 
  

   dinary 
  rod, 
  and 
  secured 
  only 
  at 
  the 
  bottom, 
  so 
  that 
  it 
  is 
  free 
  to 
  change 
  its 
  

   length 
  by 
  changes 
  of 
  temperature, 
  and 
  is 
  guided 
  at 
  the 
  upper 
  end 
  by 
  studs 
  

   standing 
  through 
  in 
  slots. 
  

  

  The 
  extent 
  of 
  graduation 
  is 
  the 
  same 
  as 
  that 
  of 
  the 
  ordinary 
  rod, 
  and 
  the 
  

   verniers 
  read 
  to 
  0.001 
  foot, 
  although 
  they 
  could 
  be 
  made 
  to 
  read 
  to 
  0.0001 
  foot. 
  

   To 
  determine 
  the 
  temperature 
  of 
  the 
  casing, 
  a 
  thermometer 
  is 
  set 
  in 
  a 
  long 
  slot 
  

   in 
  the 
  front 
  part, 
  and 
  the 
  thermometer 
  is 
  read 
  at 
  each 
  reading 
  of 
  the 
  rod. 
  

  

  That 
  the 
  rodman 
  may 
  be 
  able 
  to 
  keep 
  the 
  rod 
  vertical, 
  two 
  small 
  circular 
  

   levels 
  are 
  attached 
  to 
  the 
  back 
  of 
  the 
  rod, 
  one 
  for 
  the 
  direct, 
  and 
  the 
  other 
  for 
  

   the 
  inverted 
  position. 
  

  

  The 
  ordinary 
  back 
  part 
  of 
  the 
  rod 
  is 
  retained, 
  and 
  this 
  compels 
  to 
  the 
  as- 
  

   sumption 
  that 
  the 
  change 
  of 
  its 
  length 
  between 
  any 
  two 
  sights, 
  on 
  account 
  of 
  

   change 
  of 
  temperature, 
  is 
  inappreciable, 
  and 
  this 
  will 
  virtually 
  be 
  the 
  case 
  in 
  

   all 
  except 
  extraordinary 
  changes 
  of 
  temperature, 
  and 
  even 
  then 
  effects 
  will 
  be 
  

   much 
  less 
  than 
  ordinary 
  errors 
  of 
  observation. 
  

  

  The 
  next 
  important 
  improvement 
  I 
  have 
  added 
  is 
  a 
  tangent 
  screw 
  ; 
  but 
  this 
  

   I 
  will 
  explain 
  and 
  exhibit 
  at 
  another 
  meeting. 
  

  

  Mr. 
  Stearns 
  called 
  attention 
  to 
  the 
  fossil 
  Tooth 
  of 
  a 
  species 
  of 
  

   Elephant 
  from 
  Santa 
  Rosa 
  Island, 
  presented 
  some 
  time 
  ago 
  by 
  Mr. 
  

   W. 
  G. 
  Blunt, 
  as 
  it 
  proved 
  that 
  the 
  island 
  was 
  formerly 
  a 
  portion 
  

   of 
  the 
  main 
  land. 
  He 
  had 
  been 
  informed 
  by 
  Mr. 
  Blunt, 
  that 
  the 
  

   tooth 
  had 
  been 
  found 
  in 
  situ, 
  and 
  near 
  it 
  was 
  embedded 
  the 
  tusk 
  

   of 
  an 
  elephant 
  ; 
  the 
  latter 
  so 
  far 
  decomposed 
  that 
  it 
  crumbled, 
  in 
  

   the 
  attempt 
  to 
  get 
  it 
  out. 
  

  

  Professor 
  Davidson 
  said 
  that 
  since 
  the 
  last 
  meeting 
  of 
  the 
  

   Academy 
  he 
  had 
  examined 
  the 
  partially 
  exhumed 
  remains 
  of 
  a 
  

   large 
  animal 
  near 
  Lake 
  Merced, 
  which 
  had 
  previously 
  been 
  re- 
  

   ferred 
  to 
  by 
  Mr. 
  Hanks 
  and 
  other 
  members, 
  and 
  which 
  were 
  sup- 
  

   posed 
  by 
  some 
  parties 
  to 
  belong 
  to 
  a 
  whale 
  ; 
  steps 
  had 
  been 
  

   taken 
  to 
  secure 
  the 
  same 
  for 
  the 
  Academy's 
  museum. 
  

  

  The 
  President 
  stated 
  that 
  the 
  Trustees 
  had 
  under 
  advisement 
  

   the 
  questions 
  arising 
  from 
  the 
  terms 
  of 
  Mr. 
  Lick's 
  gifts 
  to 
  the 
  

  

  