side, the plan, etc.) is shown separately and without any distortion by perspective, and in such a manner that every portion is supposed to be opposite to the eye at once.  Only the width of any object on one side can be shown in this way at one view; for the width of the return side you have to look to another drawing; you must compare the drawings in order to find out those relative proportions which the perspective view indicates to the eye at a glance; but each portion of each side can be measured by reference to a scale, and its precise size obtained, which can only be guessed at roughly from the perspective drawing.  Thus the side of the model is shown in Fig. 19, the end in Fig. 17; the two together give the precise size and proportions of everything outside to scale, except the projection of the pilasters.  This has to be got at from the plan and section.  Everything being drawn on one plane, of course surfaces which are sloping on one elevation are represented as flat in the other.  For instance, on No. 17 the raking line of the sloping roof is shown at N. So we know the slope of the roof, but we do not know to what length it extends the other way.  This is shown on Fig. 19, where the portion showing the roof is also marked N, and it will be seen that the surface which is sloping in Fig. 17 is seen in the side elevation only as a space between a top and bottom line.  We see the length of the roof here, and its height, but for its slope we go to the end elevation.  Neither elevation tells us, however, what is inside the building; but the section (Fig. 18) shows us that it has an arched ceiling, and two stories, a lower and a higher one.  The section is the building cut in half, showing the end of the walls, the height and depth of the window openings, the thickness of the floor, etc., and as all parts which are opposite the eye are shown in the drawing, the inside of the cross wall at the end of the building is shown as a part of the section drawing, between the sectional walls.  In Fig. 23 the section is sketched in perspective, to show more clearly what it means.  Another section is made lengthwise of the building (Fig. 20).  It is customary to indicate on the plan by dotted lines the portion through which the section is supposed to be made.  Thus on the plans the lines A B and C D are drawn, and the corresponding sections are labeled with the same lines.  As with the elevation, one section must be compared with another to get the full information from them.  Thus in Fig. 18, the ceiling, M, is shown as a semicircle; in Fig. 20, it is only a space between the top and bottom lines.  It is, certainly, shaded here to give the effect of rotundity, but that is quite a superfluity.  On Fig. 18 the height of the side windows is shown at F, and the thickness of the wall in which they are made.  In Fig. 20 (F) their width and spacing are shown.  In Fig. 18 some lines drawn across, one over the other, are shown at H. These are the stairs,