﻿358 
  Notices 
  respecting 
  New 
  Books. 
  

  

  A 
  Handbook 
  for 
  the 
  Electrical 
  Laboratory 
  and 
  Testing-Room. 
  By 
  

   J. 
  A. 
  Fleming, 
  M.A., 
  D.Sc, 
  F.R.S. 
  Volume 
  I. 
  Pp. 
  viii 
  + 
  538. 
  

   London 
  : 
  The 
  Electrician 
  Printing 
  and 
  Publishing 
  Company, 
  

   Limited. 
  : 
  

  

  Dr. 
  Fleming 
  is 
  so 
  well 
  known 
  as 
  a 
  writer 
  of 
  books 
  on 
  electro- 
  

   technology, 
  and 
  his 
  success 
  in 
  this 
  line 
  has 
  been 
  so 
  great, 
  that 
  one 
  

   naturally 
  expects 
  either 
  novelty 
  of 
  matter 
  or 
  novelty 
  of 
  treatment 
  

   in 
  anything 
  bearing 
  his 
  name. 
  A 
  perusal 
  of 
  the 
  volume 
  before 
  us 
  

   has 
  not 
  disappointed 
  our 
  expectations. 
  The 
  book 
  fills 
  a 
  distinct 
  

   gap, 
  and 
  lacks 
  none 
  of 
  that 
  vigour 
  and 
  freshness 
  of 
  treatment 
  

   which 
  have 
  established 
  the 
  author's 
  reputation 
  as 
  a 
  writer 
  of 
  

   text-books. 
  

  

  The 
  introductory 
  chapter 
  deals 
  with 
  the 
  equipment 
  of 
  an 
  

   electrical 
  laboratory, 
  and 
  contains 
  a 
  detailed 
  description 
  of 
  the 
  

   various 
  standards 
  and 
  instruments 
  employed 
  in 
  electrical 
  measure- 
  

   ments. 
  The 
  author 
  recommends 
  the 
  use 
  of 
  incandescent 
  lamps 
  

   for 
  galvanometers, 
  a 
  sharp 
  image 
  of 
  the 
  filament 
  being 
  obtained 
  

   on 
  the 
  scale. 
  It 
  appears 
  to 
  us 
  that 
  this 
  method 
  is 
  never 
  so 
  good 
  

   for 
  exact 
  dejlectional 
  work 
  as 
  the 
  older 
  one 
  in 
  which 
  a 
  brightly 
  

   illuminated 
  spot 
  is 
  used 
  with 
  a 
  dark 
  line 
  across 
  it. 
  The 
  former 
  

   method, 
  is, 
  in 
  fact, 
  not 
  suited 
  to 
  a 
  really 
  dark 
  room, 
  as 
  there 
  is 
  

   then 
  no 
  illumination 
  of 
  the 
  scale, 
  and 
  it 
  becomes 
  difficult 
  if 
  not 
  

   impossible 
  to 
  take 
  readings. 
  The 
  importance 
  of 
  a 
  good 
  galvano- 
  

   meter 
  mirror 
  is, 
  perhaps, 
  not 
  sufficiently 
  insisted 
  on. 
  It 
  is 
  

   wonderful 
  how 
  mauy 
  manufacturers 
  spoil 
  their 
  highest 
  class 
  

   instruments 
  by 
  providing 
  them 
  with 
  mirrors 
  which 
  render 
  it 
  

   impossible 
  to 
  obtain 
  a 
  good 
  definition 
  of 
  the 
  " 
  spot 
  " 
  on 
  the 
  scale. 
  

   Another 
  frequent 
  source 
  of 
  annoyance 
  is 
  the 
  extremely 
  poor 
  

   optical 
  quality 
  of 
  the 
  glass 
  used 
  for 
  the 
  windows 
  of 
  galvanometer 
  

   cases. 
  Any 
  kind 
  of 
  mirror 
  or 
  glass 
  seems, 
  by 
  many 
  makers, 
  to 
  be 
  

   thought 
  good 
  enough 
  for 
  instruments 
  of 
  the 
  highest 
  finish 
  and 
  

   delicacy. 
  We 
  are 
  glad 
  to 
  notice 
  the 
  author's 
  strong 
  condemnation 
  

   of 
  all 
  the 
  usual 
  forms 
  of 
  tachometers 
  and 
  speed-indicators, 
  and 
  

   have 
  often 
  wondered 
  how 
  people 
  could 
  be 
  induced 
  to 
  squander 
  

   money 
  over 
  these 
  costly 
  but 
  useless 
  instruments. 
  The 
  extremely 
  

   sensitive 
  hydraulic 
  speed-indicator 
  described 
  by 
  the 
  author 
  should 
  

   prove 
  very 
  useful. 
  On 
  p. 
  103, 
  in 
  the 
  description 
  of 
  the 
  cadmium 
  

   cell, 
  "melted 
  paraffin" 
  should 
  read 
  " 
  paraffin 
  oil.*' 
  On 
  p. 
  127, 
  

   we 
  came 
  across 
  the 
  following 
  sentence 
  (foot 
  of 
  page) 
  : 
  " 
  the 
  

   logarithm 
  of 
  one 
  excursion 
  bears 
  a 
  nearly 
  constant 
  ratio 
  to 
  the 
  

   logarithm 
  of 
  the 
  next 
  one. 
  This 
  ratio 
  is 
  called 
  the 
  logarithmic 
  

   decrement 
  of 
  the 
  galvanometer." 
  This 
  must 
  evidently 
  have 
  been 
  

   written 
  in 
  a 
  hurry, 
  and 
  requiies 
  an 
  obvious 
  correction. 
  

  

  Chapter 
  II. 
  contains 
  a 
  very 
  full 
  account 
  of 
  various 
  methods 
  of 
  

   measuring 
  resistance. 
  In 
  describing 
  Price's 
  Guard-wire 
  method, 
  

   p. 
  290, 
  the 
  author 
  says, 
  " 
  The 
  guard 
  wire 
  short-circuits 
  the 
  

   galvanometer." 
  Surely- 
  this 
  statement 
  is, 
  to 
  say 
  the 
  least 
  of 
  it, 
  

   extremely 
  misleading. 
  At 
  the 
  end 
  of 
  this 
  chapter, 
  we 
  find 
  a 
  very 
  

   useful 
  collection 
  of 
  tables 
  of 
  resistivity. 
  

  

  