The Magic Lantern And Its Use 75


The adjustment of the light is always a matter of some little difficulty to the beginner, and by following our instructions the best illumination may be obtained with the minimum of trouble. We set up the lantern in the place it has to occupy and, from the tables we have given, the size of the picture may be known in advance, or the position of the lantern determined. We see that our light is burning properly and slide the illuminant into the lantern body, not paying much attention to perfection, providing we see some light on the screen. We next insert a lantern slide with fine detail, such as a map, in the carrier upside down and with the front of the slide facing the condenser, and draw or rack out the objective till the image is approximately sharp on the screen. Now remove the lantern slide from the carrier and proceed to adjust the light so that the rectangular opening of the lantern slide carrier is evenly illuminated on the screen. We shall probably find that this is a matter requiring adjustment, and one side or the other, or top,or bottom is not properly lit. This will show that the light is out of proper centre. If the shadow is at the top, the light is too high; and if the shadow is at the bottom, the light is too low; in fact, just the contrary to what we should expect,unless we remember that the lens transposes the image. After adjusting the position to get the margins correct, we may possibly find we have a shadow in the centre, and then the light must be drawn slightly away from the condenser. Should, on the other hand, there be a marginal fringe of colour we must push the light nearer to the condenser. After obtaining the most even illumination possible, all is ready for work.


A NATIVE OF DORT. Taken with N.S. Patent Reflex and long-focus Tele Lens.