Excerpt from Dr. Edward Kirk's System of Foundry Practice: Metallurgy of Foundry Irons and Foundry Practice This iron is the strongest of all the foundry irons and has the most marked tendency for chill when suddenly solidified against a cold chill. It was the only iron used for malleable iron and car wheels for many years, but at the present time the entire output of this iron in a year in this country is not sufficient to supply these foundries for one day, and only a few of the smaller malleable iron and car wheel plants favorably located continue to use it exclusively. Others only use about 10 per cent. To tone up their mixture of other irons, while others have been compelled to abandon its use entirely and use coke iron with steel scrap as a strengthener and chill giver. This iron is so strong that it is cast 1n pig of only about two thirds the width of those of coke iron, and the pigs are notched on both sides to facilitate breaking them for charging and melt ing. All the iron cannon used before the introduction of steel cannon were cast with this iron, and it was frequently termed gun metal. This iron, at the present time, is principally used for chilled rolls alone and in mixtures with coke iron. Outside of the Lake Superior-iron region it is principally graded by fracture indica tions. About the Publisher Forgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.com This book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully; any imperfections that remain are intentionally left to preserve the state of such historical works.