CHAPTER III.

APPLIED OPTICS--EYE-PIECES--ACHROMATIC OBJECTIVES AND CONDENSERS--MAGNIFYING POWER OF EYE-PIECES AND OBJECTIVES--METHOD OF EMPLOYING THE CONDENSER--ITS ILLUMINATION MIRROR--ACCESSORIES OF THE MICROSCOPE--FINDERS--MICROMETERS--CAMERA-LUCIDA--MICROSCOPE IN POSITION FOR DRAWING--ABBÉ’S TEST-PLATE--MICRO-PHOTOGRAPHY--POLARISATION OF LIGHT--THE MICRO-SPECTROSCOPE 139