Fourcault process the pit must be "heated back" and then the process can continue anew. Glass chemistry has a huge impact on the process since it controls the melting, forming and annealing temperatures, liquidus temperature (point where various chemicals that make up the glass start to crystallize out of the glass) and rates of change of characteristics of the glass itself. Occasionally the ribbon will break or crack, leading to failure of the drawing process. Such breaks, known as "checks" can be alleviated by using proper operating parameters. Sometimes an expedient measure, using a portable source of heat, can be used to
Ancient glass trade Ancient glass trade The ways in which glass was exchanged throughout ancient times is intimately related to its production and is a stepping stone to learning about the economies and interactions of ancient societies. Because of its nature it can be shaped into a variety of forms and as such is found in different archaeological contexts (window panes, jewellery, tableware...). This is important because it can inform on how different industries of sections of societies related to each other – both within a cultural region or with foreign societies. Glass trade is mainly studied by compositional analysis of glass objects