426         Dividing  Powders  in  Prescription  Work.  {^pimbeS"' 
inches  long,  I  inch  wide  and  T7^  inch  thick,  and  has  a  V-shaped 
groove  plowed  out  of  the  top  S/q  of  an  inch  wide  at  the  upper  end 
of  the  V  and  is  -^L  of  an  inch  deep.  At  one  end  there  is  a  gate 
swinging  on  a  screw,  which  allows  it  to  move  up  and  down  freely  to 
close  the  end  of  the  V. 
On  one  edge  it  is  laid  off  in  quarter  inches  and  numbered  by  five, 
fTTMte^ '' 1,1511 
A  Device  for  Dividing  Powders  in  Prescription  Work. 
ten,  fifteen,  twenty  and  twenty-five;  thus  every  fifth  mark  is  num- 
bered. 
The  second  piece  is  simply  a  strip  of  brass  of  an  inch  thick  and 
as  large  as  the  end  of  the  first  piece. 
