BoiFer

A ve el in which water is boiled to pro¬ savages of Australia in war or the chase. It consists of a piece of hard wood of a bent form and about two feet long. One side is flat, the other convex in shape. When thrown it has a singular motion. Instead of going forward it rises with a whirling motion, then begins to go backward, a d strikes the ground behind the thrower. The Austral i ans are very skillful in the use of this singular weapon, and can make it strike where they wish. heated in the open air, its temperature rises. After a time bubbles of vapor are formed and reach the surface, and at this stage boiling or ebullition has begun. The heat converts the water from the liquid state into the state of gas or vapor, which rises in bubbles and pa es off into tlie air as steam. The temperature at which boiling begins is called the boiling-point. Dif¬ ferent liquids have different boiling points,—that of water being 2120 F.; of alcohol, of mercury, 662°; and of acetic acid, 243.140. These are the temperatures needed at sea-level. At higher points, where the pre ure of the atmosphere is le , the boiling point is reached at lower cemperatures. used to hold something in its place, often having a head at one end and a screw thread c,t on the other, on which a movable piece called a nut is screwed.