TECNOLOGIA de metales.

As in the case of Dr. VON ZEERLEDER's previous textbook"The Tech-nology of Aluminium and its Light Alloys", a translation into Englishwas undertaken as a useful piece of work that would be of benefit to thosereaders in English-speaking countries who are interested in the manu-facture and use of aluminium and magnesium and their alloys, and whowill want to have ready recourse to an up-to-date textbook by so eminentan authority as Dr. VON ZEERLEDER.The aim of the translator has been to render the author's meaning faith-fully and to present it in aceptable style, and with the use of recognizedterminology.In •this there is somecomplication inthat there are sometimesdifferences between British and American expressions, and indulgence isrequested where reference has not been made to both. In order thatreaders in both hemispheres may be able to read the relevant quantitiesin the units to which they are accustomed, temperatures are presentedin both Centigrade and Fahrenheit, and stress units in both tons andpounds per square inch.As four years have elapsed from the completionof the Germanmanuscript to the publication of the English edition, it has been possibleto make references in the latter to several important new developmentswhich did not appear in the German edition.