INDEX 407 



PAGE 



Objectives, light grasping power of 5,8 



numerical aperture of $ 



penetrating power of 7, 8 



photographic 9 



selection of 8 



variable 6 



vertical illuminator 79 



Oblique extinction 171 



illumination with Abbe condenser 31, 33 



in refractive index determinations 189 



Ocular micrometer ratio 151 



Oculars, care of 14 



comparison 24 



compensating 13 



cross-haired 163 



goniometer 14 



Huygens 1 1 



micrometer 149, 153-155 



negative 1 1 



net ruled 208 



par focal 13 



projection 14 



positive ii 



Ramsden 1 1 



Oil globules, optic behavior of 187 



Optic axes of crystals 171 



Optics of compound microscope i 



Ordinary ray 160 



Orientating devices 115 



Orthogonal illumination 5 



Orthorhombic system, characteristics of 181 



Oxalate, potassium, as reagent 368 



Oxalates, detection of 379 



Parallel extinction I7 1 



Paraboloid dark-ground illumination 47 



Penetrating power of objectives 7, 8 



Periodic system of Mendelejeff 396 



Phosphates, detection of 380 



Platinum cups 248 



wires 121 



Pleochroism 176 



Polarizer 162 



Polarization colors 1 74 



by reflection 166 



tube 139 



Polarized light J 59 



