﻿Chemistry 
  and 
  Physics. 
  79 
  

  

  89-33 
  in 
  the 
  place, 
  respectively, 
  of 
  39-88, 
  110, 
  69-9, 
  1401, 
  232-4 
  

   and 
  88-7. 
  Most 
  of 
  these 
  changes 
  are 
  either 
  very 
  slight 
  or 
  they 
  

   involve 
  very 
  rare 
  elements, 
  but 
  the 
  change 
  of 
  about 
  1% 
  in 
  the 
  

   value 
  for 
  boron 
  is 
  of 
  considerable 
  importance. 
  — 
  Jour. 
  Amer. 
  

   Chem. 
  Soc, 
  41, 
  1881. 
  h. 
  l. 
  w. 
  

  

  6. 
  James 
  Cutbush, 
  an 
  American 
  Chemist, 
  1788-1823; 
  by 
  

   Edgar 
  F. 
  Smith. 
  16mo, 
  pp. 
  94. 
  Philadelphia, 
  1919 
  (Printed 
  

   by 
  J. 
  B. 
  Lippincott 
  Company). 
  — 
  In 
  this 
  little 
  book 
  Provost 
  

   Smith 
  has 
  made 
  an 
  interesting 
  addition 
  to 
  his 
  valuable 
  bio- 
  

   graphical 
  studies 
  of 
  early 
  American 
  Chemists. 
  The 
  story 
  of 
  

   Cutbush 
  's 
  short, 
  brilliant 
  and 
  varied 
  career 
  is 
  very 
  well 
  told. 
  

   Several 
  of 
  his 
  papers 
  were 
  published 
  in 
  the 
  early 
  numbers 
  of 
  

   this 
  Journal. 
  No 
  evidence 
  has 
  been 
  found 
  that 
  he 
  was 
  ever 
  a 
  

   regular 
  student 
  either 
  of 
  chemistry 
  or 
  of 
  medicine, 
  but 
  his 
  writ- 
  

   ings 
  display 
  evidence 
  of 
  an 
  unusual 
  education, 
  and 
  he 
  became 
  

   a 
  U. 
  S. 
  Army 
  surgeon, 
  and 
  was 
  in 
  his 
  last 
  years 
  professor 
  of 
  

   Chemistry 
  at 
  West 
  Point. 
  h. 
  l. 
  w. 
  

  

  7. 
  Sensibility 
  of 
  X-Bay 
  Analysis 
  and 
  the 
  Absorption 
  Spec- 
  

   trum 
  of 
  Radium. 
  — 
  The 
  presence 
  of 
  chemical 
  elements 
  in 
  various 
  

   materials 
  may 
  be 
  detected 
  by 
  means 
  of 
  X-rays 
  in 
  three 
  general 
  

   ways, 
  which 
  are: 
  (a) 
  by 
  incorporating 
  the 
  material 
  in 
  the 
  sur- 
  

   face 
  of 
  the 
  anticathode 
  and 
  then 
  analyzing 
  spectrally 
  the 
  pri- 
  

   mary 
  radiations 
  excited 
  by 
  the 
  impact 
  of 
  the 
  cathode 
  rays, 
  (b) 
  

   by 
  placing 
  the 
  specimen 
  (outside 
  of 
  the 
  bulb) 
  in 
  the 
  path 
  of 
  the 
  

   primary 
  rays 
  from 
  the 
  tube 
  and 
  analyzing 
  the 
  secondary 
  X-rays 
  

   emitted 
  by 
  the 
  constituents 
  of 
  the 
  substance, 
  and 
  (c) 
  by 
  record- 
  

   ing 
  the 
  edges 
  of 
  the 
  absorption 
  bands 
  arising 
  when 
  the 
  primary 
  

   rays 
  from 
  a 
  bulb 
  are 
  allowed 
  to 
  pass 
  through 
  a 
  thin 
  layer 
  of 
  the 
  

   material 
  in 
  question. 
  

  

  In 
  a 
  recent 
  paper 
  by 
  Maurice 
  de 
  Broglie 
  attention 
  is 
  called 
  

   to 
  the 
  facts 
  that 
  method 
  (a) 
  is 
  the 
  most 
  sensitive, 
  but 
  by 
  far 
  

   the 
  most 
  troublesome 
  and 
  time-consuming. 
  Method 
  (b) 
  is 
  more 
  

   convenient 
  and 
  it 
  has 
  the 
  great 
  advantage 
  of 
  conserving 
  all 
  of 
  

   the 
  specimen 
  employed. 
  The 
  author 
  mentions 
  two 
  practical 
  

   examples 
  of 
  the 
  application 
  of 
  method 
  (b), 
  namely: 
  "Certain 
  

   oxides 
  deposited 
  on 
  the 
  filament 
  of 
  a 
  wireless 
  telegraphy 
  lamp 
  

   having 
  three 
  electrodes 
  were 
  studied 
  (from 
  the 
  point 
  of 
  view 
  of 
  

   their 
  constituents 
  of 
  high 
  atomic 
  weight) 
  without 
  opening 
  the 
  

   lamp 
  bulb 
  ; 
  a 
  plate 
  of 
  gilded 
  brass 
  contained 
  in 
  a 
  microphone 
  of 
  

   a 
  submarine 
  was 
  identified 
  as 
  gilded 
  brass 
  without 
  taking 
  the 
  

   apparatus 
  to 
  pieces." 
  

  

  In 
  case 
  (c) 
  the 
  contrast 
  on 
  the 
  two 
  sides 
  of 
  the 
  edge 
  of 
  an 
  

   absorption 
  band 
  may 
  be 
  measured 
  by 
  

  

  where 
  x 
  is 
  the 
  thickness 
  of 
  the 
  absorbing 
  screen. 
  For 
  elements 
  

   having 
  atomic 
  weights 
  in 
  the 
  neighborhood 
  of 
  100, 
  /x 
  1 
  is 
  of 
  the 
  

  

  