PLATE 17. 



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Enlarging and reducing camera, showing method of mounting the apparatus. 



On the table at the left is a Petri-dish poured plate held in place by two rubber bands and ready for photographing. On the table at the right is a specia 

 camera-back used in making lantern slides. This allows the ground glass to be raised or lowered, pushed to right or left, or rotated at will. 



