PREFACE - Any new book, certainly one dealing with technical matters, ought to submit something akin to a certificate of necessity. While necessity is highly subjective, and capable of many shades of meaning, the plain fact of this case is that no concise dictionary of metallurgical terms, adapted to American needs, has hitherto been available. And so, if the need but be granted, the author may be permitted to hope that this volume, in greater or lesser measure, fills the void. Not that perfection is expected-the ideal may not even be prayed for in this all-too-imperfect world. Indeed, I realize that this book must inevitably contain at least a normal quota of error-sins of omission and commission both. For such, ignorance and/or carelessness must take full responsibility; in the interest of future editions, I shall be grateful for such corrections as may appear justified to the reader. No defense can be made, nor is any intended, for positive errors of commission. In a volume of this type, however, omissions may frequently reflect differing opinions as to what ought to be included. Probably no two students of metallurgy would quite agree on the scope of material to be presented. The problem here has been further complicated by a desire to serve, in this volume, lay workers at the bench and behind the torch no less than technologists with university training. As a consequence of this desire, many words and phrases in sciences peripheral to metallurgy have been included; setting a proper course has frequently been most difficult, threatened at once by the Scylla of incompleteness and the Charybdis of undue bulk. In its final form, this dictionary represents one man's effort at intelligent compromise. By its very nature, a dictionary can present little of new content. So many sources of information have found reflection in this volume that I am prevented from adequately acknowledging them; wherever possible, in fact, I have checked one source against another. Sucl³¢