Lithium, Li = 7. In medicine (Li_{2}CO_{3}), and in photography (LiBr). Boron, B = 11. As borax, B_{4}Na_{2}O_{7}, and as boric anhydride, B_{2}O_{3}. Fluorine, F = 19. As fluor spar, CaF_{2}, and as hydrofluoric acid, HF. Chromium, Cr = 52. As chromic anhydride, CrO_{3}, and potassium dichromate, K_{2}Cr_{2}O_{7}. Manganese, Mn = 55. As manganese peroxide, MnO_{2}, and potassium permanganate, MnKO_{4}. Cobalt, Co = 59·5 In smalt and blue glass. Nickel, Ni = 59·5 For electro-plating other metals. Copper, Cu = 63. The well-known red metal. Zinc, Zn = 65. Used for the plates of batteries, roofing, &c. Arsenic, As = 75. White arsenic (poison), As_{2}O_{3}. Bromine, Br = 80. A brown volatile liquid; sodium bromide, NaBr. Strontium, Sr = 87. In coloured fires (SrN_{2}O_{6}). Silver, Ag = 109. The well-known white metal. Cadmium, Cd = 112. In alloys. Yellow paint (CdS). Tin, Sn = 119. The well-known metal. Antimony, Sb = 120. In alloys such as type metal. Iodine, I = 127. In medicine and photography; free, and as KI. Barium, Ba = 137. "Permanent white," and as an adulterant in white lead, and in heavy spar, BaSO_{4}. Platinum, Pt = 196.} Gold, Au = 197.} Mercury, Hg = 200.} Well-known metals. Lead, Pb = 207.} Bismuth, Bi = 209. In medicine and fusible alloys. Uranium, U = 239. In green fluorescent glass. The compounds of the following metals and semi-metals have fewer applications, but are well known, and are somewhat frequently met with in nature, although in small quantities:-- Beryllium, Be = 9. Palladium, Pd = 107. Titanium, Ti = 48. Cerium, Ce = 140. Vanadium, V = 51. Tungsten, W = 184. Selenium, Se = 79. Osmium, Os = 192. Zirconium, Zr = 91. Iridium, Ir = 193. Molybdenum, Mo = 96. Thallium, Tl = 204. The following rare metals are still more seldom met with in nature, but have been studied somewhat fully:-- Scandium, Sc = 44. Germanium, Ge = 72. Gallium, Ga = 70. Rubidium, Rb = 86. Yttrium, Y = 89. Cæsium, Cs = 133. Niobium, Nb = 94. Lanthanum, La = 138. Ruthenium, Ru = 102. Didymium, Di = 142. Rhodium, Rh = 103. Ytterbium, Yb = 173. Indium, In = 114. Tantalum, Ta = 183. Tellurium, Te = 125. Thorium, Th = 232.