﻿EFFECTS 
  OF 
  SOLAR 
  RADIATION 
  — 
  O'BRIEN 
  

  

  129 
  

  

  UNTTED 
  STATE 
  3 
  

  

  Figttbe 
  20. 
  — 
  Latitude 
  belts 
  across 
  the 
  United 
  States 
  for 
  which 
  solar 
  antirachitic 
  

   effects 
  have 
  been 
  calculated. 
  

  

  Figuee 
  21. 
  — 
  Latitude 
  belts 
  on 
  the 
  earth's 
  surface 
  for 
  which 
  solar 
  antirachitic 
  

   effects 
  have 
  been 
  calculated. 
  

  

  