white iron, in which the expansion due to heating is not sufficient to overcome the original shrinkage. Wrought iron and steel, if repeatedly heated in a similar manner, while protected from oxidation, slightly contract in cubical dimensions. The expansion in grey cast iron, caused by repeated heating, is due, in part at least, to the formation of minute spaces or cavities through which air can pass, and into which water can enter. THE END Ledebur, Professor, on temper carbon, 51. on tensile tests, 113. Loam moulds, 89. MACHINE moulding, 90. Machine for transverse testing, 111. Magnetic concentrator, Magnetites, 9. 14. Malleable cast iron, 128. Medium iron, specifications for, 68. Melting points, 116. Micro-photographs, 121-128. Micro-structure of cast iron, 63, 121. Moulding machines, 90. dry sand, 83. loam, 89. sand moulding, 84. North Staffordshire ore, 15. |