Sec. 9] INCOME SUMMATION 159 
are sold. The dealer credits his stock of goods and debits 
his “cash,” while the buyer does the opposite. 
  
  
  
  
Stock of Goods Stock of Cash 
Seller. +. iced ert ausnalts +.§2 — $2 
Buyer a — $2 + $2 
  
  
  
The two transfers into which any exchange may be 
resolved are represented by the two columns of the table. 
But an exchange may also be resolved into two pairs of 
items represented by the two lines of the table. The 
items in the same horizontal line record the part taken in 
the exchange by one of the two exchangers. This pair of 
items constitutes his transaction, while the remaining pair 
constitutes, in like manner, the transaction of the other 
party to the exchange. The term “ transaction,” though 
somewhat vague in ordinary use, appears well suited to 
express the share in an exchange of one of the two who 
participate in it. 
Every exchange, then, consists of four items, and may 
be resolved either into two transfers (one for each prop- 
erty exchanged) or into two transactions (one for each 
exchanger). The first resolution has been considered; 
we proceed now to the second, and enter the subject of 
“ double-entry bookkeeping.” 
By double entry is meant the record of every double- 
faced event pertaining to a particular person, whether it 
be a transaction of that person with another or an in- 
teraction between the various categories of capital within 
his own possession. Double-entry book-keeping is most 
perfectly illustrated in the case of a fictitious person. 
The following account represents the entries during a 
given year for a dry goods company. In this account we 
observe that every item on the income side is balanced