﻿58 
  W. 
  P. 
  White 
  — 
  Specific 
  Heat 
  Determination. 
  

  

  credit 
  to 
  him, 
  by 
  Magnus. 
  21 
  The 
  hot 
  body 
  falls 
  into 
  a 
  

   deep 
  cylinder, 
  carrying 
  that 
  down 
  with 
  it 
  below 
  the 
  sur- 
  

   face 
  of 
  the 
  water. 
  The 
  water 
  closes 
  over, 
  so 
  that 
  a 
  seal 
  

   is 
  in 
  place 
  before 
  steam 
  is 
  formed 
  at 
  all. 
  This 
  method 
  

   does 
  not 
  suppress 
  the 
  splash, 
  but 
  that 
  also 
  can 
  easily 
  be 
  

   done. 
  The 
  splash 
  consists 
  of 
  two 
  parts: 
  (1) 
  a 
  throwing 
  

   of 
  water 
  aside 
  as 
  the 
  falling 
  body, 
  here 
  the 
  whole 
  cylin- 
  

   der, 
  enters; 
  and 
  (2) 
  an 
  upward 
  throwing 
  of 
  the 
  water 
  

   that 
  closes 
  over 
  the 
  body. 
  The 
  first 
  can 
  be 
  suppressed 
  by 
  

   letting 
  the 
  body 
  fall 
  into 
  a 
  tube 
  of 
  wire 
  gauze 
  ; 
  the 
  sec- 
  

   ond, 
  by 
  putting 
  around 
  the 
  top 
  of 
  the 
  falling 
  cylinder 
  a 
  

   rim 
  of 
  tinfoil, 
  which 
  collapses 
  into 
  a 
  sort 
  of 
  cone 
  as 
  

   it 
  is 
  exposed 
  to 
  the 
  pressure 
  of 
  the 
  water. 
  Even 
  with 
  

   this 
  arrangement 
  there 
  is 
  a 
  little 
  projection 
  of 
  spray 
  by 
  

   the 
  bursting 
  of 
  the 
  air 
  bubbles 
  that 
  come 
  up, 
  but 
  this 
  can 
  

   be 
  dealt 
  with, 
  since 
  it 
  does 
  harm 
  only 
  by 
  getting 
  on 
  the 
  

   outside 
  of 
  the 
  calorimeter. 
  Substitutes 
  for 
  the 
  tinfoil 
  

   rim 
  are 
  also 
  evidently 
  possible. 
  

  

  This 
  device 
  of 
  Plato's 
  seems 
  to 
  demand 
  a 
  charge 
  

   rather 
  smaller 
  in 
  comparison 
  to 
  the 
  size 
  of 
  the 
  cal- 
  

   orimeter 
  than 
  we 
  used, 
  and 
  therefore 
  a 
  smaller 
  tempera- 
  

   ture 
  rise, 
  but 
  the 
  excess 
  precision 
  already 
  attained 
  makes 
  

   it 
  possible 
  to 
  deal 
  satisfactorily 
  with 
  smaller 
  intervals. 
  

   Indeed, 
  measurements 
  even 
  ten 
  times 
  as 
  delicate 
  as 
  those 
  

   in 
  this 
  work, 
  namely 
  to 
  0-000012°, 
  have 
  been 
  made 
  22 
  

   thermoelectrically 
  with 
  almost 
  as 
  great 
  relative 
  precis- 
  

   ion 
  by 
  taking 
  very 
  great 
  care 
  of 
  the 
  surrounding 
  tem- 
  

   peratures. 
  The 
  exposure 
  error, 
  next 
  in 
  seriousness 
  to 
  

   the 
  drop 
  error 
  itself, 
  is 
  diminished 
  if 
  the 
  splash 
  is 
  elim- 
  

   inated, 
  on 
  account 
  of 
  the 
  saving 
  in 
  time. 
  Plato's 
  device 
  

   also 
  demands 
  a 
  very 
  accurate 
  drop, 
  so 
  that 
  to 
  drop 
  down 
  

   a 
  tube, 
  as 
  Plato 
  did, 
  seems 
  essential. 
  But 
  this, 
  though 
  

   presenting 
  some 
  complications, 
  may 
  more 
  than 
  make 
  up 
  

   for 
  them 
  by 
  simplifying 
  the 
  problem 
  of 
  starting 
  -the 
  drop 
  

   in 
  the 
  right 
  direction. 
  

  

  The 
  relatively 
  large 
  size 
  of 
  the 
  charges, 
  50 
  to 
  80 
  

   grams, 
  used 
  in 
  the 
  present 
  work 
  seems 
  to 
  have 
  been 
  justi- 
  

   fied 
  by 
  the 
  resulting 
  diminution 
  of 
  the 
  drop 
  loss 
  error. 
  

   If 
  the 
  practical 
  avoidance 
  of 
  this 
  error 
  enables 
  smaller 
  

   charges 
  to 
  be 
  used, 
  there 
  will 
  be 
  a 
  gain 
  not 
  only 
  in 
  cost 
  

   of 
  material 
  but 
  in 
  uniformity 
  of 
  temperature 
  in 
  the 
  fur- 
  

  

  21 
  A. 
  Magnus, 
  Ueber 
  die 
  Bestimmungen 
  spezifischer 
  Warmen, 
  Ann. 
  Phys., 
  

   31, 
  601, 
  1910. 
  

  

  -In 
  this 
  laboratory 
  by 
  Mr. 
  E. 
  R. 
  Edson 
  of 
  the 
  Mellon 
  Institute 
  of 
  Indus- 
  

   trial 
  Resenrcli. 
  

  

  