In Fig. 379 we have the four most com- 
monly used sizes of the A-format series. 
The largest is A-l, the next A-2 and so 
on. Thus we can have two sheets of A-4 
from one of A-3, etc. 
    This series of page formats is extreme- 
ly rational and economical in use. It has 
brought simplicity and good order to every 
stockist of paper who has practised the 
system. If he has a stock, for example of 
A-1 sheets, he is able quickly and without 
any waste whatsoever to cut a supply 
of any of the other sizes -- an important 
factor in the busy printing industry of to- 
day. 

             So with the A-format. We need not 
know the sizes in order to lay down the 
proportions, but for the record the
 respective sizes in use in Europe are 
as follows:      
      
             A-1 = 840 x 594 
              A-2 = 594 x 420 
              A-3 = 420 x 297 
              A-4 = 297 x 210 
              A-5 = 210 x 148.5 

    Research into the history of the  
A-format leads to a misty wilderness.