﻿434 
  

  

  Col. 
  J. 
  T. 
  Smith 
  on 
  the 
  

  

  [May 
  27, 
  

  

  been 
  lubricated, 
  and 
  also 
  when 
  burnt 
  clay-moulds 
  were 
  used 
  — 
  the 
  only 
  

   case 
  in 
  which 
  the 
  phenomenon 
  did 
  not 
  occur 
  being 
  when 
  clay-moulds 
  

   heated 
  to 
  redness 
  were 
  used, 
  and 
  the 
  melted 
  metal, 
  instead 
  of 
  being 
  

   poured 
  in 
  at 
  the 
  top, 
  was 
  caused 
  to 
  rise 
  from 
  the 
  bottom 
  upwards. 
  

  

  It 
  was 
  also 
  found 
  that, 
  by 
  using 
  artificial 
  means 
  to 
  cool 
  the 
  ingots 
  from 
  

   their 
  upper 
  surface 
  only, 
  the 
  usual 
  refinement 
  was 
  prevented, 
  and 
  the 
  

   metal 
  might 
  be 
  caused 
  to 
  become 
  as 
  inferior 
  in 
  quality 
  at 
  the 
  top 
  as, 
  in 
  

   the 
  ordinary 
  course, 
  it 
  would 
  have 
  been 
  at 
  the 
  bottom. 
  

  

  In 
  short, 
  after 
  many 
  experiments, 
  it 
  was 
  satisfactorily 
  established 
  

   that, 
  whatever 
  form 
  the 
  metal 
  might 
  take, 
  the 
  act 
  of 
  cooling 
  caused 
  a 
  

   partial 
  separation 
  of 
  the 
  copper 
  towards 
  the 
  surfaces 
  from 
  which 
  the 
  heat 
  

   was 
  abstracted, 
  those 
  parts 
  of 
  a 
  bar 
  or 
  ingot 
  being 
  the 
  finest 
  which 
  con- 
  

   gealed 
  the 
  last. 
  

  

  The 
  experiments 
  here 
  referred 
  to 
  were 
  part 
  of 
  a 
  series 
  constituting 
  a 
  

   minute 
  aualysis 
  of 
  all 
  the 
  ordinary 
  processes 
  of 
  a 
  mint, 
  with 
  the 
  view 
  

   of 
  discovering 
  the 
  unavoidable 
  causes 
  of 
  the 
  loss 
  of 
  precious 
  metal, 
  if 
  

   any, 
  and 
  measuring 
  their 
  amount. 
  In 
  the 
  course 
  of 
  the 
  series 
  more 
  

   than 
  3700 
  assays 
  were 
  made 
  of 
  standard 
  silver 
  under 
  various 
  conditions 
  ; 
  

   and 
  the 
  result 
  was 
  a 
  demonstration 
  of 
  the 
  fact 
  that, 
  with 
  the 
  exception 
  

   of 
  the 
  very 
  inconsiderable 
  proportion 
  left 
  in 
  the 
  sweepings, 
  which 
  might 
  

   be 
  reduced, 
  in 
  silver 
  coinage, 
  to 
  less 
  than 
  the 
  twenty 
  thousandth 
  part, 
  

   no 
  loss 
  whatever 
  ought 
  to 
  occur 
  ; 
  and 
  hence 
  that, 
  if 
  the 
  quantity 
  left 
  in 
  

   the 
  " 
  sweep 
  " 
  be 
  ascertained 
  and 
  allowed 
  for, 
  every 
  particle 
  of 
  silver 
  

   intrusted 
  to 
  the 
  Mint 
  might 
  be 
  accounted 
  for. 
  This 
  was 
  actually 
  done 
  

   in 
  1854-55 
  by 
  a 
  coinage 
  of 
  more 
  than 
  24 
  tons 
  of 
  silver 
  into 
  3,458,000 
  

   pieces, 
  when 
  every 
  ounce 
  was 
  reproduced, 
  even 
  taking 
  into 
  account 
  the 
  

   " 
  turn 
  of 
  the 
  scale 
  " 
  in 
  assays 
  given 
  in 
  favour 
  of 
  the 
  purchaser. 
  

  

  But 
  this 
  close 
  agreement 
  between 
  the 
  receipts 
  and 
  deliveries 
  of 
  a 
  

   mint 
  requires 
  not 
  only 
  an 
  exact 
  valuation 
  of 
  the 
  bullion 
  delivered 
  to 
  it, 
  

   but 
  also 
  an 
  equally 
  exact 
  valuation 
  of 
  the 
  coins 
  produced 
  by 
  it 
  ; 
  and 
  a 
  

   somewhat 
  curious 
  result 
  followed, 
  as 
  a 
  corollary 
  to 
  the 
  phenomenon 
  

   above 
  described 
  — 
  namefy, 
  that 
  as 
  the 
  ingots 
  showed 
  a 
  uniform 
  difference 
  

   in 
  their 
  various 
  parts, 
  so 
  the 
  laminated 
  straps, 
  formed 
  by 
  reducing 
  the 
  

   same 
  ingots 
  to 
  one 
  twelfth 
  of 
  their 
  original 
  thickness, 
  show 
  similar 
  

   varieties, 
  and 
  the 
  coins 
  cut 
  from 
  the 
  straps 
  also. 
  

  

  A 
  minute 
  examination 
  of 
  all 
  the 
  various 
  parts 
  of 
  laminated 
  straps 
  

   proved 
  that 
  there 
  must 
  be, 
  in 
  all 
  cases, 
  a 
  difference, 
  and 
  in 
  some 
  cases 
  

   an 
  important 
  one, 
  in 
  the 
  fineness 
  of 
  the 
  several 
  parts 
  of 
  every 
  coin, 
  

   depending 
  upon 
  the 
  position 
  it 
  occupied 
  in 
  the 
  laminated 
  strap 
  from 
  

   which 
  it 
  was 
  cut. 
  On 
  a 
  careful 
  examination 
  of 
  the 
  latter 
  there 
  was 
  found 
  

   to 
  be, 
  as 
  in 
  the 
  ingots, 
  a 
  systematic 
  variation 
  between 
  the 
  finenesses 
  of 
  

   the 
  parts 
  rolled 
  out 
  from 
  the 
  top 
  and 
  bottom, 
  and 
  also 
  between 
  the 
  sides 
  

   and 
  centre. 
  In 
  like 
  manner, 
  as 
  the 
  centre 
  of 
  an 
  ingot 
  is 
  finer 
  than 
  the 
  

   sides, 
  so 
  the 
  central 
  line 
  of 
  the 
  strap 
  formed 
  from 
  it 
  is 
  finer 
  than 
  the 
  

   edges, 
  and 
  this 
  to 
  a 
  degree 
  frequently 
  exceeding 
  the 
  allowed 
  " 
  remedy 
  " 
  

  

  