You are to learn how to make welds with the oxy-acetylene torch and to study the construction and' principles of the apparatus. These are simple but like many other simple matters they require clear understanding. Before taking up torch welding in detail, we will give a little study to the blacksmith's forge, and forge welding. If you first clearly comprehend the principles of the forge fire you can more easily comprehend the oxy-acetylene torch and its operation. You will see more clearly why it is such an efficient welding tool when handled by a skilled workman, and will be more likely to avoid' making those mistakes that result in poor welds and waste.