=9.= The sales book used in this set exhibits some features not heretofore shown. At the right are three columns for the distribution of sales. At the left, in addition to columns for number, date, and folio, are two columns headed cash and sales ledger. All cash sales are entered in the cash column, and all sales on account are entered in the sales ledger column. At the end of the week or month the total of the sales ledger column is posted to the debit of the _sales ledger account_ in the general ledger, while the totals of the sales columns at the right are posted to the credit of the _sales account_ in the general ledger. INVOICE REGISTER =10.= A form of purchase book, which also combines an invoice register, is shown in this set. Unlike the forms of purchase book with which the student has been made familiar, this invoice register gives full particulars as to terms, discount, when due, and when and how paid. The combined footings of the two department columns must of course agree with the footing of the amount column. At the end of the month the total of the amount column is posted to the credit of _purchase ledger account_ in the general ledger, and the totals of the department columns are posted to the debit of the _purchase account_ in the general ledger. The details of payment are kept in the invoice register as a memorandum only. This provides a convenient record of unpaid invoices, showing when each is due. CASH BOOK =11.= In this set we introduce a columnar cash book which also serves as a journal for cash transaction and is known as a cash journal. The principal advantage of a columnar book lies in the opportunity to introduce columns with special headings for accounts to which entries are frequent. Not only does this permit of carrying footings to the end of the month with one posting to the ledger account, but it provides a convenient classification of receipts and expenditures with a complete segregation of items of a given class. In the form illustrated, columns are provided on the debit side for cash, purchase ledger (subdivided for discount and amount), bank deposits, and sundries; on the credit side, cash, sales ledger (subdivided for discount and amount), cash sales, bank withdrawals, and sundries. At first glance it might appear that this form is a departure from the regular form of cash book, but it should be remembered that the cash columns are the only ones having anything to do with the cash account. A cash receipt is entered in the cash debit column, but the amount is credited to its source through the proper credit column; thus a payment received on account is debited to cash and credited through the sales ledger column. A deposit is credited to cash and debited to bank deposits; the payment of a purchase ledger account by check is credited to bank withdrawals, and debited to purchase ledger account.