THE POPULAK EDUCATOE. 



parallel perpendicular retiring planes. The tops of the steps 

 are horizontal retiring planes. In Fig. 31 the lid of the box 

 %;om its position is an inclined retiring piano. 



We advise the pupil now to make himself familiar with the 

 following fixed principles relating to retiring lines and planes: 



1. The Line of Sight, or, as it is sometimes called, the hori- 

 zontal line, represents the height of the eye in the picture, 

 which, when wo come to the explanation of those terms, we will 

 mark in the illustrations H L (see Figs. 28 and 29). 



2. The Point of Sight, marked P s, is the point opposite the 

 eye in the picture, and is consequently upon the line of sight. 



3. The Station Point is the place where the spectator is 

 supposed to stand when viewing the object represented ; 

 marked S p. 



4. A Ground Plan is the horizontal extent of the object when 

 drawn upon the ground. 



5. The Vanishing Point is that point in the plane or surface 

 of the picture, where retiring lines if produced or continued, 

 would meet or terminate ; marked V P. 



6. All retiring lines have vanishing points. 



7. All horizontal retiring lines have their vanishing points 

 upon the line of sight. 



8. All parallel retiring lines have the same vanishing point. 



each way within a greater angle, he would have to trn his 

 head, and consequently he would require two or more points of 

 sight ; this is only allowable in panoramas (viz., long pictures 

 generally placed upon upright rollers, and so drawn out as a 

 ribbon would be from a reel), when the view of a country for 

 any number of miles in extent is exhibited ; the proper or nioro 

 convenient distance from the object is, when it is placed withir. 

 an angle of from 20 to 25. 



Let a b, Fig. 25, ba two objects to be drawn in tho camo 

 picture ; the distance from them at c would be the nearest 

 approach we could make ; then the angle a c b would be an 

 angle of 60. If we removed our position to d, then the anglo 

 would be much less, and more suitable for our picture. 



We beg it may be understood that hereafter when we say 

 drawing from Nature, we allude to all objects, trees, buildings, 

 etc. Although buildings are not natural objects, yet they are 

 included under this expression. 



4th. Ground Plan. The best illustration of a ground plan is 

 a map ; it has nothing to do with heights or depths. Suppose 

 the walls of a house were removed, and only the foundations 

 left, we should then see the plan of the house. 



5th. Vanishing Point (v P). If a line be drawn from the eye 

 parallel to any original straight line of the object the point 



Tig.25 



9. All horizontal lines which are parallel with the picture 

 plane, are drawn parallel with each other, and the line of sight. 



10. All horizontal retiring lines forming right angles with 

 the picture plane, or with our position, have the point of sight 

 for their vanishing point. 



11. All lines inclined with the horizon, and with the picture 

 plane, have their vanishing points above or below the line of 

 sight, according to the angle they form with the horizon, their 

 vanishing points being always on a line perpendicular to the 

 vanishing point upon the line of sight, to which they would 

 have retired had they been horizontal. 



Before going any further we will endeavour to explain the 

 above fixed principles or definitions, taking them in their order. 



1st. The Line of Sight, H L (horizontal line), is drawn parallel 

 with the base of the picture, according to the height of the eye 

 .from the ground. If we are drawing a house from a higher 

 ipoint of view than when standing or seated on the ground, the 

 line of sight will be higher in the former than in the latter case. 



2nd. The Point of Sight (P s) is subject to the same conditions 

 as to its height from the ground as the line of sight. 



3rd. The Station Point (s P) may be at almost any distance 

 from the object that is most convenient; but observe, if too 

 near, we get a distorted view of the object when drawing from 

 Nature. Let the reader for a moment place himself in an up- 

 right position, keep his head perfectly still, and turn his eyes to 

 the right and to the left ; all that he can possibly see whilst so 

 doing is included in an angle of 60 (sixty degrees), considerably 

 too near the objects he is looking at to make a pleasing picture, 

 though it would not be wrong. But if he included mere objects 



where that line cuts the picture plane (or surface of the picture) 

 is the vanishing point of that original line. When the pupil 

 has read this, let him rise from his chair, and stand about eight 

 or nine feet from the window, and look out upon the objects 

 beyond. Suppose that a house is in sight, having one of its cor- 

 ners towards him. If he stood without moving from the position 

 he has chosen, and took a long stick having a piece of charcoal, or 

 something that will make a mark on glass, fastened to the end, 

 he might trace the form of the house upon the glass in the same 

 way as tracing a drawing through a piece of thin paper; he 

 would then have made a true perspective drawing of that house 

 upon the glass. This glass is the picture pla:ie; the place 

 where he stands when making the tracing is the station point. 

 Now, supposing the retiring side of the building he is tracing is 

 on the left as he looks at it, let him raise his left arm and hold 

 it parallel to that retiring face or plane of the building, he will 

 then be pointing to the vanishing point of the retiring face or 

 plane, and all horizontal lines upon that plane would be retiring 

 also, and consequently meet at the same vanishing point. 



He might, for the sake of experiment, actually make a 

 tracing on the window of one or more of the parallel retiring 

 lines of the building, and at the same time make a mark upon 

 the wall for the vanishing point. Then if he continue the traced 

 lines on the glass he would eventually find that they will meet 

 the mark upon the wall, that mark being the vanishing point ; 

 and he would also find thatf the mark upon the wall is on a level 

 with his eye, on the line of sight. He would find also that if there 

 were any other lines parallel with the window, those lines when 

 traced would bp parallel with the line of sight, and be drawn 



