﻿566 
  Scientific 
  Intelligence. 
  

  

  the 
  civil 
  service 
  examinations 
  for 
  second 
  division 
  clerkships. 
  

   About 
  the 
  same 
  amount 
  of 
  space 
  is 
  devoted 
  to 
  the 
  subjects 
  of 
  

   mechanics 
  and 
  heat. 
  Ample 
  opportunity 
  is 
  afforded 
  the 
  student 
  

   to 
  apply 
  the 
  principles 
  explained 
  in 
  the 
  text 
  by 
  solving 
  the 
  prob- 
  

   lems 
  (333) 
  collected 
  at 
  the 
  ends 
  of 
  the 
  chapters 
  and 
  by 
  perform- 
  

   ing 
  the 
  experiments 
  (68) 
  suggested. 
  The 
  various 
  constituent 
  

   parts 
  of 
  each 
  half 
  of 
  the 
  book 
  form 
  a 
  very 
  coherent 
  whole, 
  and 
  

   the 
  illustrations 
  are 
  apt 
  and 
  well-drawn. 
  In 
  particular, 
  the 
  sec- 
  

   tions 
  dealing 
  with 
  steam 
  and 
  internal-combustion 
  engines 
  seem 
  to 
  

   be 
  especially 
  attractive. 
  The 
  text-proper 
  is 
  followed 
  by 
  tables 
  of 
  

   physical 
  and 
  mathematical 
  constants, 
  answers 
  to 
  the 
  numerical 
  

   exercises, 
  and 
  a 
  subject 
  index. 
  h. 
  s. 
  u. 
  

  

  12. 
  Practical 
  Physics 
  for 
  Secondary 
  Schools 
  ; 
  by 
  N. 
  Henry 
  

   Black 
  and 
  Harvey 
  N. 
  Davis. 
  Pp. 
  ix, 
  487, 
  with 
  465 
  figures 
  and 
  

   IV 
  plates. 
  New 
  York, 
  1913 
  (The 
  Macmillan 
  Co.).— 
  One 
  of 
  the 
  

   most 
  important 
  principles 
  used 
  consistently 
  throughout 
  this 
  book 
  

   is 
  expressed 
  by 
  the 
  following 
  quotation: 
  " 
  We 
  believe 
  that 
  it 
  is 
  

   most 
  important 
  for 
  teachers 
  to 
  select 
  carefully 
  just 
  what 
  material 
  

   they 
  can 
  best 
  use, 
  and 
  to 
  teach 
  that 
  thoroughly, 
  rather 
  than 
  try 
  

   to 
  touch 
  upon 
  many 
  topics 
  superficially." 
  The 
  value 
  of 
  the 
  text 
  

   is 
  enhanced 
  by 
  the 
  summaries 
  of 
  principles 
  which 
  are 
  given 
  in 
  

   full-faced 
  type 
  at 
  the 
  end 
  of 
  each 
  chapter. 
  The 
  volume 
  contains 
  

   an 
  unusually 
  large 
  number 
  (769) 
  of 
  numerical 
  problems 
  and 
  ques- 
  

   tions. 
  The 
  latter 
  are 
  especially 
  well 
  selected 
  and 
  are 
  calculated 
  

   to 
  make 
  the 
  student 
  observant 
  and 
  thoughtful. 
  Two 
  examples 
  

   may 
  not 
  be 
  superfluous: 
  " 
  Why 
  is 
  it 
  that 
  the 
  United 
  States 
  and 
  

   Great 
  Britain 
  are 
  the 
  only 
  two 
  civilized 
  countries 
  that 
  do 
  not 
  use 
  

   the 
  metric 
  system 
  commercially?" 
  and 
  "Mark 
  Twain 
  in 
  his 
  

   ' 
  Tramp 
  Abroad 
  ' 
  tells 
  of 
  stopping 
  on 
  his 
  way 
  up 
  a 
  mountain 
  to 
  

   < 
  boil 
  his 
  thermometer.' 
  What 
  did 
  he 
  do, 
  and 
  why 
  ? 
  " 
  

  

  On 
  the 
  other 
  hand, 
  the 
  manner 
  of 
  presentation 
  of 
  certain 
  topics 
  

   is 
  open 
  to 
  serious 
  question. 
  The 
  authors 
  say 
  : 
  " 
  Our 
  treatment 
  of 
  

   acceleration, 
  Newton's 
  laws, 
  kinetic 
  energy 
  and 
  momentum, 
  is 
  

   essentially 
  different 
  from 
  either 
  the 
  dyne 
  and 
  poundal 
  method 
  

   common 
  in 
  physics 
  textbooks, 
  or 
  the 
  "slug" 
  or 
  "wog" 
  method 
  

   of 
  engineers, 
  and 
  is 
  apparently 
  new." 
  Newton's 
  second 
  law 
  is 
  

   stated 
  : 
  " 
  The 
  acceleration 
  of 
  a 
  given 
  body 
  is 
  proportional 
  to 
  the 
  

   force 
  causing 
  it." 
  This 
  law 
  is 
  formulated 
  as 
  

  

  "F_ 
  a 
  " 
  

  

  " 
  It 
  [the 
  dyne] 
  can 
  be 
  defined 
  as 
  1 
  / 
  980 
  of 
  a 
  gram 
  weight." 
  Again 
  : 
  

  

  Wv 
  

  

  " 
  The 
  expression 
  — 
  - 
  is 
  called 
  the 
  momentum 
  of 
  a 
  moving 
  

  

  body" 
  Finally: 
  " 
  The 
  resistance 
  of 
  a 
  mil 
  foot 
  of 
  wire 
  is 
  some- 
  

   times 
  called 
  the 
  specific 
  resistance 
  of 
  the 
  substance. 
  ..." 
  

  

  h. 
  s. 
  u. 
  

  

  13. 
  Beyond 
  the 
  Atom; 
  by 
  John 
  Cox. 
  Pp. 
  151 
  ; 
  11 
  figures 
  

   and 
  1 
  plate. 
  Cambridge, 
  1913 
  (University 
  Press). 
  — 
  "This 
  essay 
  

  

  