Brick earths, artificial mixing, 42 artificial mixtures, 94, 95 bluish-black, 27 boulder clay, 50 brown, 27 chalk pebbles in, 50 changes in character on being dug into, 2, 5, 10 chemical composition of, 23, 52, 83, 84, 85 chemistry of, 58, 75 chert in, 41, 42 coprolites found in, 51 Cornwall, 35 Crayford, 1 Devon, 35 Erith, 1 estuarine, 21 fluviatile--Chapter I., 1–16 fossil shells in, 50 Ilford, 1 Kimeridge clay, 26 lacustrine--Chapter II., 17–21 Lincolnshire, 21 London clay, 33 marine, 22 mineral constitution, 28 minerals found in (see Kaolin, Felspar, Quartz, Flint, Mica, Iron, Calcite, Aragonite, Selenite, Dolomite, Salt, etc.). Northamptonshire, 21 North-Eastern France, 20 Oxford clay, 33 Reading mottled clay, 19 of river terraces, 12 salt in, 25 sea-shore, 25 section of fluviatile brick-earths, 10 several kinds of fluviatile, discussed, 14, 15 Switzerland, 89 Thames Valley, 1, 2, 3, 4, 5 value of chemical analyses of, 28, 29 Brickmaking: earths suitable for (see Brick-earths) Bricks, abrasion tests, 146 absorption of, 132 basic, 90 Bracknell, 135 colour of, 100 Dinas, 81 discolouration of, 114 durability of, 103 effect of conflagrations on, 117 efflorescence on, 110 London stock, 97 micro-structure of, 29, 118, 128 rubber, 29 specific gravity, 146, 149 Staffordshire blue, 99 Stourbridge, 82 strength of, 136 vegetable growth on, 113 weathering of, 105, 113 British Museum, fossils in, from brick-earths, 3, 26 Bronzite, 69 Brown brick-earths, 27 Burning bricks, 94 changes produced by, 98 temperature, 89 Calc spar, 49 Calcite, 39, 49 behaviour in kiln, 39 micro-structure of, 131 under blow-pipe, 74 Californian magnesite, 56 Carbon dioxide in quartz, 41 Carbonate of lime (see Calcite, Aragonite) Chalk in brick-earths, 1 mixed with brick-earths, 53 pebbles in brick-earths, 50 Chateauroux, Oxford clay of, 24 Chemical affinity, 76 analyses of brick-earths, 28 analysis, 77 composition of air, 106 composition of brick-earths, Dinas, 52 composition, china clays, 78 composition of fire-clays, 80 composition of Kieselguhr, 92 composition of magnesian limestones, 90 composition, pottery clays, 82 composition of slates, 87 disintegration of rocks, 20 re-agents, 60, 63, 71 Chemistry of brick-earths, 58, 75 Chert, 41 Cheshire, salt in clays in, 25 China-clays, behaviour in the kiln, 36 chemical composition, 78 Cornwall, 35, 36, 37 Devon, 35 China-clay (see Kaolin and Felspar) thickness of, 38 China-stone, decomposed, 37 Colour in the kiln, 98, 99 Colouring matter of bricks, 45 of bricks, 53 Colour of bricks (see Blue, Black, etc.).