﻿BICHMOND. 
  

  

  Fia. 
  I. 
  — 
  Showing 
  the 
  variation 
  of 
  the 
  striation 
  with 
  diameter 
  of 
  tube. 
  

  

  3 
  mm. 
  

  

  6 
  mm. 
  

  

  9 
  mm. 
  

  

  12 
  mm. 
  

  

  22 
  mm. 
  

  

  33 
  mm. 
  

  

  44 
  mm. 
  

  

  •67 
  mm. 
  

  

  •58 
  

  

  •82 
  mm. 
  

  

  •59 
  mm. 
  

  

  •63 
  mm. 
  

  

  •47 
  mm. 
  

  

  •57 
  mm. 
  

  

  The 
  diameters 
  of 
  the 
  tubes 
  are 
  written 
  on 
  the 
  left 
  and 
  the 
  strise-distances 
  on 
  tbe 
  right. 
  

  

  