584 Proceedings of the Boy at Society 
ary 1807, accompanied by an engraving well executed by D. 
Lizars. 
The engraving shows a rectangular structure with a tower at 
each corner, drawn in what is usually called perspective. The 
west faces of the building are in bright sunshine; the north 
faces are less brilliantly lit, but are not in shade, and the N.W. 
turret casts a shadow on the middle North Wall. 
Brewster had changed the direction of the source of light from 
W. to E. ; he had put a gate-way in the north wall where Yince 
has none ; had altered considerably the style of the architecture, 
and had, in one respect to be afterwards noticed, improved the 
drawing. 
Recollecting that Dover is S.S.W. from Ramsgate, we perceive 
that the trend of the picture plane is W.N.W. ; now the west 
face of the building is shown as inclined to the line of sight 
toward the west ; its trend must be about S. W. by S., and therefore 
that of the N. face about N.W. by W. Hence, looking at the 
shadow upon that north face, we judge the sun to have been in 
the N.W. ; and, looking at the slope of that shadow, to have had 
an altitude of about 44°, and this at 7 h. on the 6th of August. 
On putting the celestial globe into position for the time stated, 
we find that the sun must have been shining from among the 
small stars of the Great Bear. The shadow of the building upon 
the ground to the east, corroborates the story. Thus far the 
Astronomer ; next the Architect ; he says, and at a glance, there 
is no member of the structure which could, under any circumstances, 
have caused the shadow as shown in the figure. 
Let us go more carefully into the matter. When a drawing of 
any rectangular structure is given in perspective, it is easy to 
deduce the distance of the point of sight from the picture, as 
well as the relative positions and proportionate sizes of the parts. 
Taking the extreme bounding lines as the basis, we find the 
vanishing point for the north face to be 193*2 inches to the left; 
that for the west face to be 3*7 to the right, counting from the 
middle of the picture. These give 26*6 inches for the eye’s 
distance from the paper, and an inclination of 7° *50' of the north 
face to the picture plane. 
The bearing of Dover from Ramsgate, computed from the 
geographical positions, is 20°*4', west of south, hence the trend 
