Page:Madras journal of literature and science vol 2 new series 1857.djvu/265

changed the right one becoming the left and vice versâ. Whilst for glass positives it is necessary to use separate glasses, the frame having a smaller central support as below. As the centre of the lenses in taking Stereoscopic pictures is a little above the centre of the Camera, the position of the glass plate must be made to correspond.

I do not observe that the glasses being parallel instead of converging towards the object makes any perceptible difference in the pictures, but when a table is used to support the Camera, such convergence might be easily given by having a pivot under the front of the Camera and limiting its lateral motion by screws placed as in the accompanying figure F.

I have found it impossible to get made here the rather complicated exposing frame usually described in books on taking Stereoscope pictures, when a system of parallel bars is used on a table to shift the Camera and at the same time to move the collodionized plate. With a Camera constructed as above the parallel frame might be used with advantage for groups of figures and distant objects, moving

SS two snipe shot which allow it to
move easily.

the object glass in a direction contrary to that given to the Camera, when the pictures would be in their correct places on the glass. I send enclosed a picture or two which will show that