— = 
ge, ~~ 
Miscellaneous Intelligence. 141 
In the above we have given only the simpler forms of the ster- 
foscope for the sake of illustrating the principle on which it is con- 
structed. They are forms that might be made without the aid of an 
Optician, 
L 
quired distance between the pictures, look at one 
he eye-piece, and after obtaining the distance off for the 
Posed, it would give a hollow cone; or by using three figures, placing 
another B (which we a. ddioate B’) to the left of A, the hollow and 
sed cone may be seen, alternately, according as B’ or B is superim- 
Teosen.. © Of the two kinds of the requisite nicety for use in the ste- 
» Photography or a binocular camera is required. 
