gray iron are each given a single line, whereas these names are

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gray iron are each given a single line, whereas these names are generic and include a rr-ide range of analyses and properties. I n contrast, a number of alloy steels of very similar analyses and properties are listed individually and n i t h trade names. The editor has had the assistance of a number of capable educators and technical inen in preparing the handbook. -111 are to be congratulated on the results of their work. The fifth edition, like earlier editions, has made available a niass of valuable material for the technical library. H. H . B A R B EASD R H. F. SCOBIE.

JT h e Total u)id Frce Energies of Forniatioiz of the G x i d e s o j Thirty-tito X e t a l s .

By MAL-RICE DEI