The artists repository and drawing magazine: exhibiting the principles of the polite arts in their various branches (3.1789)

[ i07 ]
very much changed by the obliquity os the sur-
face, the situation os the luminary, or the na-
ture of the object; all which causes vary the
sorce of reflexion.
In looking at this mahogany table, the
edge nearest to us seems enlightened ; this light
at a very lmall distance indeed, becomes mode-
rated; a little further off is yet more decreased,
and as we advance toward the other extremity,
it ceases to be light, and may rather be deno-
minated a slight shade. This effect is very
regular and constant, because the surface is uni-
form j and, consequently, its obliquity and de-
clination uniform also : but, if in any part of
the table we place a surface somewhat more
elevated in its position (as this drawing board)
the nearest end of that sursace does not
perfectly correspond in its degree of light with
that part of the table where it is placed, but
the light is some degrees brighter, and, as it
were, sets off afresli on this new surface from
its hither end, gradually decreasng to its fur-
ther end ; the waving of the grain in a corn
field, whose agreeable movement we have al-
ready noticed, depends much on this : the
various directions of the undulating surface,
perpetually distinguishing themselves by break-
ing the uniformity of the general plane.
2 But,