There is no good reason why an alphabetical card ledger should not be as safe as the numerical. If it is desired to guard against the removal of one card and the substitution of another, the blank cards should be placed in the custody of one man, who will issue them to the bookkeeper as needed, first placing his initials on the card. In any event, the card ledger should be provided with a locking device which will prevent the removal of a card, except by the one who has the key. These suggestions may be of assistance to the bookkeeper who is called upon to use a card ledger. Never leave ledger cards lying on the desk. When you leave your work, put them back in the file, where they belong. Before leaving the office, lock the ledger so that no one can remove a card in your absence. If your superior asks you to see a certain ledger account, do not give him that one card. He may lose it. Give him the entire tray, with the cards securely locked. Should he insist on having that one card, ask him to give you a receipt for it. Some special forms of ledger cards are illustrated. Fig. 21 _a._ is a form used by a dental supply house. The special feature of the form is a separate column for each different class of goods purchased by the customer. Fig. 21 _b._ is used by a publisher for advertising accounts. Fig. 21 _c._ is a conventional balance ledger form adapted for use in almost any line of business. =24. Tabular Ledger.= This is a ledger in which the names are written down the side of the page, with debits, credits, and balances extending across the page. Columns are arranged to group entries during uniform periods, as a month, week, or day. A special feature of this style of ledger is that it can be more quickly balanced and proved than any other style. To prove this ledger add the balances at the end of the preceding period to the debit postings of the current period. This will equal the total of the credit postings added to the new balances, if the balances have been correctly extended. The postings to all of the accounts on a page—30 to 40—can be footed at one operation, saving much time. Fig. 22 _a._ is a form of a tabular ledger used by banks, known as the _Boston bank ledger_. It is specially arranged to exhibit daily balances, as it is necessary that the depositor's ledger be balanced daily. This form can be used in a mercantile business, but as balances are not required daily, the form shown in Fig. 22 _b._ is better adapted to the purpose. These tabular forms of ledgers are not commonly used except in banks. =25. Balance Ledgers.= Three forms of balance ledgers are illustrated, each one of which is specially adapted to some particular class of business. [Illustration: Fig. 22 _a._ Boston Bank Ledger ] [Illustration: Fig. 22 _b._ Commercial Tabular Ledger ]