Camera Lucida . 
26 ? 
No. 54. 
Description of the Camera Lucida . By William EL 
Wollaston, Secretary of the Boyal Society.* 
(With an engraving.) 
HAYING a short time since amused myself with at- 
tempts to sketch various interesting views, without an 
adequate knowledge of the art of drawing, my mind was 
naturally employed in facilitating the means of transfer- 
ring to paper the apparent relative positions of the objects 
before me ; and I am in hopes that the instrument, which 
I contrived for this purpose, may be acceptable even to 
those who have attained to greater proficiency in the 
art, on account of the many advantages it possesses over 
the Camera Ohscura. 
The principles on which it is constructed will probably 
be most distinctly explained by tracing the successive 
steps, by which I proceeded in its formation. 
While I look directly down at a sheet of paper on my 
table, if I hold between my eye and the paper a piece 
of plain glass, inclined from me downwards at an an- 
gle of forty-five degrees, I see by reflection the view 
that is before me, in the same direction that I see my 
paper through the glass. I might then take a sketch 
of it; but the position of the objects would be reversed. 
To obtain a direct view, it is necessary to have two re- 
flections. The transparent glass must for this purpose 
be inclined to the perpendicular line of sight only the half 
of forty-five degrees, that it may reflect the view a second 
time from a piece of looking glass placed beneath it, and 
inclined upwards at an equal angle. The objects now 
appear as if seen through the paper in the same place as 
before ; but they are direct instead of being inverted, and 
Nicholson, vol. 37, p. 1. 
