To sum up a simple classification, which may be termed the triology of the orders, will be found to assist the memory. The Orders commonly employed are three--the Doric, Ionic and Corinthian. (There are two others which are less used, and are really derived from the other three: they are the Tuscan, which is a form of debased Doric, and the Composite, which is made up of the Ionic and Corinthian). The Order may be divided into three parts: Pedestal, Column and Entablature. These may again be sub-divided. The Pedestal into Plinth, Die and Capping. The Column into Base, Shaft and Capital. The Entablature into Architrave, Frieze and Cornice. The method of arriving at the proportions of the order is as follows. In this division the pedestal is not taken into account, but is reserved for later consideration. _Doric Order_ Divide the total height into five equal parts. Then the upper fifth will give the height of the entablature and an eighth of the remaining four-fifths the diameter of the column. From this it will be seen that the column is eight diameters high and the entablature two diameters. In using the term diameter it must be understood that it is always the lower diameter of the column that is referred to. [Illustration: No. 154. General Proportions of the Orders.] The capital is half a diameter high exclusive of the necking moulding, and the base also is half a diameter. In all the orders the column is tapered; the upper diameter is in each case five-sixths of the lower or major diameter. The taper is not in a straight line, but a slight curve, which is known as entasis. It is obtained by drawing the lower third of the shaft vertical and from these lines springing a curve to the upper diameter, which may readily be done by slightly altering the angle of the pencil in ruling them. The entablature is divided as follows: the architrave is half a diameter, the frieze and cornice each three-quarters of a diameter. _Ionic Order_ The total height should be divided into six parts. Then the upper sixth will be the entablature, and one ninth of the remainder the diameter of the column, hence the column will be nine diameters high. The capital is half a diameter high; the base also is half a diameter. The total height of the entablature is divided into ten parts, three of these should be taken as the height of the architrave, three that of the frieze and the remaining four that of the cornice. _Corinthian Order_ The total height should be divided into six parts. Then the upper sixth is the height of the entablature. A tenth of the remainder will be the diameter of the column. The capital is one diameter and one-sixth in height exclusive of the necking moulding, and the base is half a diameter high, exclusive of the top fillet.