All photographic exposures being somewhat in the nature of an experiment, because of the ever-varying conditions of the atmosphere, it is possible only to give approximate times. Over-exposed plates may be corrected by careful development ; but a very much under-exposed plate is past remedy, and a slow plate is more easily dealt with than a fast one. As a rough guide to a beginner, exposure meters may be of service, but, if followed too slavishly, they may prove worse than use-less. The following is the minimum exposure for June, 11 a.m. to 1 p.m.: - Clouds, 1/60 see.; sea and sky, 1/40 see.; open landscape (distant objects only), 1/8 sec.; buildings (well illuminated) 1/2 see.; groups (light dresses), 1/2 see.; groups (dark and heavy contrast), 1 see. It is impossible to classify interiors as light and dark to be of any use. The only practical plan is to make a trial exposure and develop the plate. If it is impossible to develop a trial plate, make several exposures of different lengths. In all exposures the colour of the light and the degree of contrast in the subject and that required in the-picture must be taken into account. It may here be mentioned that one would hardly attempt clouds, sea, or sky in the middle of the day.

Bear in mind the old rule, "Expose for the shadows, and let the lights take care of themselves."