In recent years, the typewriter companies have placed devices on their typewriters which permit of the sales sheet being held independently of the invoices. This permits one to hold the large sales sheet in the machine until enough invoices have been manifolded thereon to cover the page, at which time the sales sheet is reversed. The invoices can be placed in the machine and removed therefrom after being written, without interfering with the sales sheet. No extra width of invoice is required, which permits of old stationery being used in the form of invoices. The flat-bed machines can use old stationery, but not quite so well. However, when billing by machinery, it is false economy to use stationery designed for pen work. The reasons for this will be touched upon later. The use of two ledgers necessitates the use of two columns at the right side of the page. All names from _A_ to _L_ are placed in the first column; all names from _M_ to _Z_ are placed in the second. For instance, an invoice reading as shown in the sales journal, Fig. 11, illustrates the idea of writing the totals in the two columns at the right side of sheet according to the initials of the last name of the firm or the individual, as the respective ledgers are arranged in that manner. If at the end of the month the first column shows a total of $3,000.00 the bookkeeper knows that he has posted that amount into Ledger _A-L_, etc. The above plan enables the bookkeeper to add separately the totals which are posted to the respective ledgers. The desire to separate the charges to a country ledger and a city ledger can be accomplished by using two columns in the same way. The desire to place all credit memoranda in the sales book can be accomplished by using two columns in the sales book as noted above. The first column is used for the charges, and the second one for entering the credits. One difficulty arises in connection with this plan. Credits are liable to be entered in the debit column. To obviate this, the invoices are made just wide enough to reach over the first column, the credit memoranda are made wider to reach over the last column. When an amount is written in the last column of the invoice, it manifolds in the proper column of the sales sheet. The same is true of an amount written in the last column of a credit memo. This subdivision of columns is carried a step further to permit of the analyzation of sales in several ways. According to classes of goods, as follows: [Illustration] [Illustration: LAMSON FOUR-INCH PNEUMATIC TUBE ORDER CARRYING SYSTEM FOR A LARGE WHOLESALE ESTABLISHMENT OR A FACTORY Lamson Consolidated Store Service Co. ] [Illustration: Fig. 11. Sales Journal Arranged for Distribution to Two Ledgers ] According to territory, as follows: [Illustration] According to salesmen, as follows: [Illustration] To separate the sale of regular goods from goods which are being sold on consignment, as follows: [Illustration]