﻿132 
  Johnston 
  — 
  Temperature 
  in 
  Deejp 
  Wells 
  at 
  Findlay. 
  

  

  of 
  course 
  be 
  so 
  far 
  below 
  the 
  thermometers 
  that 
  the 
  heat 
  

   absorbed 
  by 
  it 
  is 
  not 
  abstracted 
  from 
  the 
  zone 
  the 
  temperature 
  

   of 
  which 
  is 
  desired. 
  Likewise 
  the 
  thermometers 
  should 
  be 
  a 
  

   considerable 
  distance 
  below 
  the 
  bailer, 
  which 
  is 
  a 
  convenient 
  

   means 
  of 
  minimizing 
  

   perchance 
  be 
  present. 
  

  

  There 
  are 
  a 
  number 
  of 
  circumstances 
  which 
  affect 
  the 
  tem- 
  

   perature 
  of 
  bore-holes 
  ; 
  we 
  cannot 
  discuss 
  them 
  here, 
  but 
  shall 
  

   point 
  out 
  one 
  or 
  two 
  of 
  the 
  more 
  common 
  conditions 
  likely 
  to 
  

   cause 
  errors. 
  Temperatures 
  at 
  the 
  bottom 
  of 
  a 
  hole 
  should 
  

  

  any 
  convection 
  currents 
  which 
  might 
  

  

  30 
  

  

  25 
  

  

  U 
  

  

  0.2O 
  

  

  ijj 
  

   r- 
  

  

  15 
  

  

  10 
  

  

  Fig. 
  1. 
  

  

  f 
  

  

  1000 
  

  

  DEPTH 
  

  

  2000 
  

   FEET 
  

  

  3000 
  

  

  Fig. 
  1. 
  Curve 
  showing 
  the 
  relation 
  between 
  observed 
  temperature 
  and 
  

   depth 
  in 
  the 
  bore 
  hole 
  at 
  Findlay, 
  Ohio. 
  

  

  not 
  be 
  taken 
  until 
  at 
  least 
  twenty- 
  four 
  hours 
  have 
  elapsed 
  since 
  

   drilling 
  was 
  discontinued 
  or 
  since 
  water 
  was 
  poured 
  in 
  the 
  

   hole 
  ; 
  otherwise 
  it 
  is 
  uncertain 
  if 
  the 
  temperatures 
  observed 
  

   really 
  represent 
  the 
  temperature 
  of 
  the 
  rock 
  at 
  the 
  depth 
  in 
  

   question. 
  Moreover 
  the 
  temperature 
  of 
  water 
  brought 
  up 
  in 
  

   the 
  bailer 
  is 
  no 
  certain 
  criterion 
  of 
  the 
  temperature 
  down 
  

   below, 
  for 
  if 
  the 
  bailer 
  is 
  raised 
  quickly, 
  the 
  friction 
  against 
  

   the 
  casing 
  may 
  be 
  sufficient 
  — 
  in 
  deep 
  wells, 
  especially 
  — 
  to 
  pro- 
  

   duce 
  a 
  temperature 
  actually 
  higher 
  than 
  that 
  obtaining 
  down 
  

   at 
  the 
  bottom 
  of 
  the 
  hole. 
  But 
  the 
  factor 
  which 
  perhaps 
  in- 
  

   tervenes 
  most 
  frequently 
  and 
  most 
  seriously 
  in 
  the 
  attempted 
  

   determination 
  of 
  the 
  temperature 
  of 
  the 
  rock 
  (as 
  distinct 
  from 
  

   that 
  of 
  the 
  air 
  or 
  gas 
  in 
  the 
  hole) 
  is 
  the 
  flow 
  of 
  gas, 
  which 
  in 
  

  

  