Oldal 42 [42]
20 LIGHT AND WATER
should great accuracy be required; though, as water
is hardly ever quite still, reflexions are seldom dis¬
tinct enough to need very exact drawing.
But whatever the object reflected, whether build¬
ing, rock or tree, it is important to bear in mind that
the image of any point lies exactly beneath that
point, and must therefore be drawn vertically below
it. A slight neglect of this precaution may destroy
the whole force or charm of a sketch. It sometimes
happens, however, that the reflexion of a sloping
tree-stem appears to be shifted a little to one side,
for the base of the stem, though itself in full view,
cannot be seen by reflexion, its image being hidden
by the image of the bank, and the first appearance
of the stem in the water is therefore to one side of
the base. If the water is a little rippled, so that the
image is drawn out and blurred, the deception may
be increased. And when the ripples are running
both in the object and the image, such as E, will converge to the
other vanishing point VP. Draw a vertical line through VP’.
Then whatever pitch we choose for the roof of the house, the edges
F, G, of the near side must vanish to an accidental vanishing
point in this line above VP’, say AVP’. The roof of the small
building has the same pitch, and therefore F, G, I and K are all
representations of parallel lines and must all meet at the point
AVP’. And it may easily be shown (assuming the farther and
nearer slopes of the roof to be of the same pitch) that the edges
H, L, of the farther side will vanish to a corresponding point, av/’,
as far below VP, as AVF ts above tt.
Now, in the image, the nearer edges f, g, ? and & of the
gables are parallel to the farther edges H, L in the object, and
also 4, / in the image are parallel to F, G, I and K in the object.
Therefore the lines 7, g, z, & will vanish also in av, and 4, 7 in
AVP’.