Another illustration of the effect of description on the classification is found in shipments of carriages. The classification, and consequent rate, on this commodity is based on the space that it will require, rather than on the rate. If shipped knocked down and properly crated, with the dimensions stated on the shipping bill, a carriage takes a lower classification than if shipped assembled, or if the dimensions of the crate are omitted. These illustrations are sufficient to show the importance of a thorough knowledge of the provisions of the different classifications. The shipping clerk who would give the best service to his house should make a study of this subject, even if he is obliged to take the classifications home and study them at night. Every shipper should see that his shipping clerk is supplied with copies of classifications governing the territory in which he is doing business, and give him an opportunity to learn their provisions in respect to the commodities which he ships. =Class Rates.= A _class rate_, as the name implies, is one based on the classification. All commodities are divided into classes, six in number, and all commodities of the same class--with certain exceptions, explained later--take the same rate. Schedules of rates between given points, based on the class, are prepared by the classification committees, but before being put into effect, they must, in case they apply between points in different states, be submitted to the Interstate Commerce Commission for approval. While not a _rate-making_ body, the commission is a _rate-governing_ body, constituting, in a certain sense, a board of arbitration between shippers and transportation companies. The rates being based on the classes--the higher the class, the higher the rate. To determine the rate, it is first necessary to find the classification; reference to the rate schedule will show the rate for each class. =Commodity Rates.= A commodity rate is one applying to a special commodity, between definitely stated points. Commodity rates are established by the railroads to meet some special condition, and with these the classification committees have nothing to do. A commodity rate does not apply to articles not named in the tariff even though they are of a similar nature, nor do they apply between points not specified in the special tariff. A commodity rate is, in effect, a special rate; it offers special inducements for the shipment of certain commodities, but is not intended to favor any one shipper. The commodity rate is for the benefit of all shippers of the commodity named.