Show HOW CAST RON GROWS gas in the mater a Is cause of sup posed phenomenon rhe fact that iron abes grow has been investigated by a writer in the journal of the franklin institute who as known iron to grow as much as pr cent in the course of repeated tea tines in explaining this growth he as that cast iron has many minute av t es which are filled with a mix ure of ases when the iron is highly bated thee u naturally expand and cause the iron which Is then corn oft to stretch in booling he iron hardens again but the very elgh pressure of the enclosed gases prevents the iron from contracting to ts former damens ons with every renewed heating the process Is repeat d and at each cool ng the pressure of ae enclosed gases becomes less and esa as the cavities increase in size bit anere is a limit to this action of hp gases and this is reached when the cavities become so large that the pi assure of the enclosed gases is not i to overcome the resistance offered by the softened iron when abis point is arrived at the iron a to row |