﻿THE 
  

  

  AMERICAN 
  JOURNAL 
  OF 
  SCIENCE 
  

  

  [FOURTH 
  SERIES.] 
  

  

  Art. 
  I. 
  — 
  Silicate 
  Specific 
  Heats. 
  Second 
  Series; 
  by 
  

   Waltee 
  P. 
  White. 
  

  

  This 
  paper 
  extends 
  in 
  scope 
  and 
  accuracy 
  some 
  work 
  

   previously 
  published. 
  1 
  The 
  several 
  objects 
  in 
  view 
  are 
  

   indicated 
  in 
  the 
  discussion 
  of 
  the 
  results. 
  The 
  methods 
  

   were 
  described 
  briefly 
  in 
  the 
  earlier 
  publication, 
  and 
  in 
  

   more 
  detail 
  in 
  two 
  later 
  papers 
  ; 
  2 
  some 
  further 
  improve- 
  

   ments, 
  which 
  were 
  used 
  in 
  most 
  of 
  the 
  work 
  here 
  

   described, 
  will 
  be 
  presented 
  in 
  a 
  paper 
  following 
  this. 
  

   Here 
  it 
  seems 
  sufficient 
  to 
  recall 
  the 
  main 
  features 
  of 
  the 
  

   experimental 
  procedure, 
  which 
  were: 
  (1) 
  The 
  charges 
  

   of 
  silica 
  or 
  silicate 
  were 
  heated 
  in 
  electric 
  or 
  steam 
  

   heaters, 
  with 
  particular 
  care 
  to 
  secure 
  both 
  constant 
  and 
  

   uniform 
  temperatures. 
  (2) 
  These 
  charges 
  were 
  dropped 
  

   into 
  the 
  calorimeters 
  by 
  an 
  automatic 
  arrangement, 
  

   which 
  secured 
  uniformity 
  and 
  quickness. 
  (3) 
  The 
  con- 
  

   tainer 
  was 
  also 
  dropped 
  empty, 
  in 
  order 
  to 
  eliminate 
  the 
  

   heat 
  losses 
  in 
  the 
  drop. 
  (4) 
  A 
  special 
  guard 
  was 
  used 
  

   to 
  prevent 
  water 
  from 
  splashing 
  on 
  the 
  outside 
  of 
  the 
  

   calorimeter. 
  (5) 
  The 
  calorimeter 
  after 
  the 
  drop 
  was 
  

   completely 
  inclosed 
  away 
  from 
  the 
  air 
  of 
  the 
  room, 
  and 
  its 
  

   temperature 
  was 
  measured 
  thermoelectrically 
  with 
  a 
  

   sensitiveness 
  of 
  0-0003° 
  or 
  (usually) 
  of 
  0-0001°. 
  

  

  The 
  questions 
  of 
  interest 
  connected 
  with 
  these 
  specific 
  

   heats 
  usually 
  depend 
  on 
  relatively 
  small 
  differences 
  either 
  

   between 
  the 
  specific 
  heats 
  of 
  similar 
  substances 
  or 
  be- 
  

   tween 
  those 
  of 
  the 
  same 
  substance 
  at 
  different 
  tempera- 
  

  

  1 
  Walter 
  P. 
  White, 
  Specific 
  Heats 
  of 
  Silicates 
  and 
  Platinum, 
  this 
  Journal, 
  

   28, 
  334, 
  1909. 
  

  

  2 
  Walter 
  P. 
  White, 
  Some 
  Calorimetric 
  Apparatus, 
  Phys. 
  Kev. 
  31, 
  670, 
  

   1910; 
  Easy 
  Calorimetric 
  Methods 
  of 
  High 
  Precision, 
  J. 
  Am. 
  Chem. 
  Soc. 
  

   36, 
  2313, 
  1914. 
  

  

  Am. 
  Jour. 
  Sci. 
  — 
  Fourth 
  Series, 
  Vol. 
  XL 
  VII, 
  No. 
  277. 
  — 
  January, 
  1919. 
  

  

  1 
  

  

  