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systems of perspective are acknowledged and acted upon by 
artists. We may call these spherical , cylindrical , and plane 
perspective. 
A painting upon the interior of a spherical dome, or a view 
taken by Sutton’s beautiful spherical lens, is an illustration of 
the first system ; Burford’s or Selon’s views on the walls of a 
circular apartment, or the pantascopic views, illustrate the 
second system ; and an ordinary perspective drawing, or a 
view taken with a triplet or new doublet lens, furnishes us 
with an illustration of the third system, or that which is 
usually employed by artists. 
Now all these are really true, but to be absolutely so, the 
pictures must be viewed upon surfaces similar to those upon 
which they have been projected, and from the same station 
point. 
Mr. Sutton’s pictures must be taken and viewed upon 
bowls of glass, the eye being in the position of the lens when 
the view was taken. With Burford’s panorama we must 
place ourselves in the centre of the room and turn round so 
as to view the picture as we should view the landscape it 
represents. 
This is equally true of a picture in plane perspective, so 
that if we really insist upon absolute truth in viewing a 
picture taken by a lens of four-inch focus, the picture must be 
brought within that distance from the eye, or the extreme 
lateral objects will not fall upon the retina at that angle which 
they would do in viewing the landscape itself. 
As our object is usually to produce pleasing pictures, 
rather than an absolutely truthful representation of the scene, 
the discrepancy between the pantascopic pictures viewed flat 
is rarely objectionable, indeed, if we examine the numerous 
views before us, we shall see that in many of them the 
widening of the base line is advantageous, and often adds to 
the value of the picture, by giving better arrangement or 
composition. Perfect truth may at all times be obtained by 
