stands out in bold relief toward sunset; for then the long rays of sunlight parallel to earth light up the hills and ridges leaving the hollows and the canyons in shadow. At noon with nearly vertical illumination, the mountain looks flat and uninteresting. The whole character of the final print depends primarily on the character of the illumination. The lighting is of primary importance; everything else is secondary. No skill in developing, retouching, or printing will make up for a faulty illumination.

With insects and plant structures, a low light from the side brings out longitudinal ridges and sulci into bold relief. light from the end developes transverse ridges and sagmentation. A high light displays surface detail, the coloring and ornamentation of smooth surfaces. All this of course implies control of the direction of the light rays.

With sunlight such control is to be obtained by reflecting the light at various angles from a hand mirror held by a clip on a ring stand. With the tungsten bulb, the angle of the light and the consequent character of the illumination are to be varied by changes in the position of the bulb; now high, now low, now at the end of the stage, now at one side. With diffused light from a north window, excessive top light may be cut off by lowering the window curtain half way or more.

V. Methods of Work.

A. The Preparation of the Object.

Small entomological and botanical objects may best be mounted on glass slides for convenience in manipulation. With Coccidae, portions of twigs with level surfaces should be chosen or slices of bark may be cut with a scalpel and temporarily mounted on a slide with a drop of liquid glue or thick Canada balsam. Every effort should be made to bring all the region which is to be photographed as nearly as possible within one plane. After the subject has been mounted, it is advisable to go over it with the moistened tip of the finest camels' hair brush removing tiny bits of dust and shreds of bark and the like; for every grain of dust or every meaningless bit of debris when magnified attracts attention and confuses the image. Oftentimes it is advisable to stain the grey bark on which grey Coccids rest for the sake of increased contrast. It is useful, too, to spray other subjects with a mist of distilled water from an atomizer as the moistened subject then presents increased contrast. B. Plates, Development and Printing.