If the sensitive plate has been exposed to a landscape, the strongest actinic rays come from the blue sky, and as the chemical used to develop or bring out the image affects the part which has been exposed to the strongest light most quickly, the result in the negative is the opaque deposit which covers all that part of the plate exposed to the light from the sky. After the image has appeared on the plate it must undergo another process to make it permanent. It must be placed in a chemical solution which shall dissolve the silver salts from the parts unaffected by the actinic rays. Where the actinic light has been the strongest the glass will be covered with a black deposit, and where the light has not reached the plate with sufficient force the salts will be dissolved and the glass will be clear, while the high lights, the shadows, and the half-tones will show just how much each object reflected actinic rays. We manage our cameras, but the sun is the real work-man. What he does is well worth learning, for it enables us to tell beforehand just what kind of a negative we shall have after we have exposed a sensitive plate to his influence. ROUND TABLE PHOTOGRAPHIC EXCHANGE CLUB. Our suggestion of forming a photographic exchange club, or travelling photographic exhibit, meets with the warm approval of many of our members. Next week we shall give directions for beginning and carrying on our club. We give the names and addresses of members who will act as representatives. Ernest P. Fredericks, Arlington, New Jersey; Samuel J. Castner, 3729 Chestnut Street, Philadelphia, Pennsylvania; Walter G. Sill, 511 Central Avenue, East Orange, New Jersey; Andrew Phillips, Nunda, New York; C. Roy Baker, 315 W. Dry Street, Salem, Ohio; William J. Tobey, Washington, Kansas; William C. Davids, Rutherford, New Jersey.