A _purchase controlling account_ exhibits a summary of all accounts in the purchase ledger. It is called a Purchase Ledger Account, Accounts Payable Account, or Purchase Controlling Account. These controlling accounts are kept in the general ledger and show at all times the totals of accounts receivable and accounts payable, without the necessity of listing the individual balances. At the end of the month statements of the balances of the accounts in purchase and sales ledgers are made, and the totals of these balances must agree with the balances of the controlling accounts. The operation of these controlling accounts demonstrates one of the most apparent advantages of the division of the ledger. If an error is made in posting to an account in the sales ledger it is discovered as soon as the statement of the sales ledger is made, and can be located without referring to purchase or general ledger accounts. Without the ledger division and the use of controlling accounts, there would be nothing to assist in locating an error in the trial balance in any particular section of the ledger. ORDER BLANKS =7.= In a wholesale business it is customary to have all orders entered on specially ruled order blanks of a uniform size. These orders are filed in a binder designed for the purpose, which takes the place of the old style order book. These order blanks are furnished to salesmen who send in their orders on them. When an order is received direct from the customer it, also, is transcribed on one of these blanks so that all order records will be uniform. One very appreciable advantage in the use of this loose sheet system of order blanks is that all unfilled orders are kept in a binder by themselves. =8. Filling Orders.= Each day the orders to be filled should be placed in a temporary binder or holder and sent to the warehouse. The packer will check quantities shipped and return the order, together with the shipping receipt from the railroad or express company, to the bookkeeping department. The amounts are extended, and the invoice is made out from this order blank. The sale is next recorded in the sales book. Instead of entering each item in the sales book the totals for each department are entered in the proper column. Each sale is numbered in the sales book as illustrated and the same number is placed on the order. These orders are then filed in the binder for filled orders in exact numerical order, which brings them also in the order of the dates of shipment. [Illustration: Order Blank ] SALES BOOK