Illuminating power of gas, 266 of mantles, ~294~ Ilmenite, 17, ~57~, 90 Ilmenorutile, 17, 71 Johnstrupite, 17, 55 Kainosite, 18, 45 Karyocerite, 12 Kataplejite, 12, 51 Keilhauite, 18, ~52~ Kischtimite, 18, ~81~ Knopite, 18, 59 Kochelite, 18, 64 Koppite, 18, 64 Lanthanite, 18, ~79~ Lanthanum, atomic weight of, ~173~ compounds of, ~172~ detection of, 173 metallic, ~115~, 171 separation of, ~170~ Lavenite, 19, 51 Lead, 105, ~107~ Lederite, 54 Leucosphenite, 19, 55 Leucoxene, 55 Lewisite, 19, 59 Lighting devices, ~315~ Ligurite, 54 Loranskite, 19, 64 Lorenzenite, 19, 55 Lutecium, ~205~ Mackintoshite, 19, 79 Magnetic susceptibility, ~152~ Malacone, 19, 49 Mauzeliite, 20, 59 Melanocerite, 20, 51 Menaccannite, ~57~ Mengite, 84 Mesothorium, ~252~, 276 Metals of rare earth group, ~114~ Michaelsonite, ~14~ Microlite, 20, 64 Misch metal, ~115~, ~315~ Molengraafite, 20, 55 Monazite, 4, 20, ~82~ sands, 83, ~90~ technical treatment of, ~276~ Mosandrite, 20, 55 Muromontite, 20, 42, 45 Naegite, 31, 45, ~49~ Narsarsukite, 21, 55 Neodymium, atomic weight of, ~179~ detection of, ~180~ metallic, 115, 177 oxides, ~177~ salts, ~178~ Neoytterbium, 206 Neptunite, 21, 55 Nernst lamp, ~320~ Nitrates of rare earth group, ~128~ Nitrides of rare earth group, ~116~ Nivenite, 21, 73 Nohlite, 21, 64 Octahedrite, 8, ~78~ Oerstedite, 21, ~49~ Oisanite, 78 Orangite, 21, ~45~ Organic salts of rare earth group, ~133~ Orthite, 8, ~39~ Oxalates of rare earth group, ~131~ Oxides of rare earth group, 115, ~117~ Parisite, 21, ~80~ Pauly process, ~303~ Perovskite, 14, 22, 59 Peroxides of rare earth group, ~117~ Pertitanates, ~235~ Phosphates of rare earth group, ~129~ Phthalates of rare earth group, ~134~ Picroilmenite, 16, ~59~ Pictite, 54 Pilbarite, 22, ~49~ Pitchblende, 22, ~72~ Platinocyanides of rare earth group, ~123~ Platinum mantles, ~268~ Plumboniobite, 22, ~62~ Polonium, 99 Polycrase, 22, ~66~ Praseodymium-- atomic weight of, ~175~ compounds of, ~174~ detection of, 176 history of, 168 metallic, ~115~, 174 separation of, ~170~ Priorite, 22, ~66~ Pseudobrookite, 22, 59 Pyrochlore, 23, 71 Pyromorphite, 101 Pyrophanite, 23, 59 Pyrophoric alloys, ~314~ Radioactivity, ~99~ Radiothorium, 74, 99, ~253~ Ramie, mantles of, ~291~ Rare earth mixtures, examination of, ~147~ Rare earths-- extraction of, from minerals, ~147~ and periodic classification, ~135~ Retzian, 23, 88 Rhabdophane, 23, 88 Rhönite, 23, 55 Rinkite, 23, 55 Risörite, 23, 38, ~69~, 102 Rogersite, 24, 64 Rosenbuschite, 24, 55 Rowlandite, 24, 55 Rutile, 24, 45, ~77~, 90