Am.  Jour.  Pharm.  \ 
October,  1903.  J 
Standard  Sieves. 
461 
mesh  in  wire-cloth  is  the  distance  from  the  centre  to  the  centre  of 
the  wire  per  linear  inch.  But  when  we  turn  to  the  list  of  the  grades 
manufactured,  it  is  discovered  that  for  No.  20  mesh  of  brass  and 
copper. wire  cloth,  twelve  different  thicknesses  of  wire  are  listed,  a 
No.  20  mesh  and  No.  23  wire  costing  $2.50  per  square  foot,  and 
going  up  regularly  in  the  list  to  No.  34  wire,  which  is  25  cents  per 
square  foot.  It  will  be  noticed  that  there  is  a  great  difference  in 
price — one  being  ten  times  the  price  of  the  other.  No.  20  iron  or 
steel  wire  cloth  made  from  No.  24  gauge  wire  is  priced  at  62  cents 
per  square  foot,  while  the  same  No.  20  wire  cloth,  when  made  of 
No.  36  wire,  is  priced  at  9  cents  per  square  foot.  It  is,  of  course, 
understood  that  the  higher  numbers  refer  to  wires  of  smaller 
diameter. 
It  can  easily  be  seen  that  a  No.  20  sieve  made  with  No.  24  gauge 
wire  would  not  let  nearly  as  much  powder  through  its  meshes  as 
would  a  No.  20  sieve  made  with  No.  36  wire.  The  illustrations 
herewith  presented  will  make  this  fact  clear.  No.  20  sieves  made 
with  thick  wire  would  really  yield  a  No.  30  powder.  Samples  are 
shown  herewith  which  demonstrate  the  above  facts. 
Drug  millers  and  manufacturers  of  pharmaceutical  preparations 
have  probably  been  aware  of  these  facts,  but  it  is  to  be  regretted 
that,  up  to  this  time,  they  have  never  engaged  the  attention  of  revis- 
ion committees  of  the  Pharmacopoeia. 
The  Clinton  Wire  Cloth  Company,  the  Estey  Wire  Works  Com- 
pany, George  A.  Williams  &  Sons,  Howard  and  Morse,  and  the 
DeWitt  Wire  Cloth  Company,  and  others,  have  all  agreed  that  the 
.following  grades  should  be  regarded  as  the  standard  : 
12  mesh,  No.  24  wire. 
20  mesh,  No.  28  wire. 
30  mesh,  No.  31  wire. 
40  mesh,  No.  33  wire. 
50  mesh,  No.  35  wire. 
80  mesh,  No.  38  wire. 
And  inasmuch  as  these  grades  represent  what  is  usually  sent  on 
orders,  when  not  otherwise  designated,  it  would  be  most  convenient 
and  desirable  to  establish  such  for  the  national  standard. 
It  is  not  intended  by  this  paper  to  reflect  in  the  least  upon  the 
honesty  of  either  the  manufacturer  of  wire  cloth  or  the  drug  miller. 
The  question  of  the  durability  of  the  cloth  and  the  character  of  the 
