held against the opening in the floor of the dark chamber by the strong springs of the object holder. There is only one mirror reflection, that by which the light passing from the object through the projection lens is directed toward the screen. This reflection at the same time causes the image to… … Figure 4—Universal Balopticon, ERVA 15, Showing Vertical Attachment and Medium Microscope, 4250 U. With the addition of the vertical attachment organisms in water, physical, chemical and biological demonstrations, or any subjects which must be placed in a horizontal position, can be projected on…
