There are certain profits which arise from other sources than the sale of goods in which the concern is trading. Among other sources are interest and premiums and profits on the sale of bonds and stocks. All such items should be listed separately each month that the amount of unusual profits may be known. This statement presents a history of the progress of the business reduced to its final analysis--that of actual net profits. MAILING-ROOM MACHINERY Mechanical devices and machines are used for many purposes in an office, and both the variety of uses and types of machines are steadily increasing. Inventors and manufacturers of office appliances are working constantly to perfect devices which will save time, insure accuracy, and reduce costs. Among the important devices are several designed to reduce labor and insure increased speed in the mailing room. =Addressing Machines.= One of the most efficient labor-saving devices is the addressing machine, which is used for addressing envelopes, cards, and other matter, to a large list of names. These machines are especially well adapted for the names to which communications are addressed at regular intervals. Brokers and commission men use them for addressing daily market letters to permanent lists of correspondents; business houses in all lines find them convenient for monthly statements, using the machine both for addressing the envelopes and filling in the names on the statements. An office boy can fill in addresses on statements for all accounts in the sales ledger, and address the envelopes, saving about one-half the time of the bookkeeper. In the advertising and sales department, the addressing machine is used to excellent advantage for addressing follow-up letters, booklets, circulars, and catalogs. Its use makes it easy to send advertising literature to all customers at frequent intervals. The machine is not recommended for a prospective customer's follow-up list, unless a large number of follow-ups are to be sent; but when a man becomes a customer, it may be safely assumed that the name is permanent. Of the machines now on the market, one of the best known is the _addressograph_. This machine is made with both card addresses and chain addresses. The card machine, which is shown in Fig. 21, is the most practical for the uses to which the machine is put in the average office. With this machine, metal frames the size of an index card are used. These frames are made in two styles, one of which has a metal printing plate, while with the other, the name and address are set in rubber type. With the first style, the printing plate is made by stamping the letters on a sheet of metal. This makes a permanent address, which cannot be changed without making a new plate. [Illustration: Fig. 21. The Addressograph Addressing Machine _Addressograph Co._]