Scottish polearms and early 16th centuries. Though clearly a pole weapon, its exact form is obscure. David Caldwell suggests it may have been similar to a Holy Water Sprinkler. The Jeddart staff (also Jedburgh or Jedwart) is a polearm of the 16th and 17th centuries with a glaive-like blade which is fixed to its haft by two sockets, in the manner of a bardiche. Form D in the Caldwell classification. The Lochaber axe is a simple axe with a broad curved blade usually attached to its long haft at two points. On the back of the blade is a simple hook. This
Types of volcanic eruptions Types of volcanic eruptions Several types of volcanic eruptions—during which lava, tephra (ash, lapilli, volcanic bombs and volcanic blocks), and assorted gases are expelled from a volcanic vent or fissure—have been distinguished by volcanologists. These are often named after famous volcanoes where that type of behavior has been observed. Some volcanoes may exhibit only one characteristic type of eruption during a period of activity, while others may display an entire sequence of types all in one eruptive series. There are three different types of eruptions. The most well-observed are magmatic eruptions, which involve the decompression of gas within magma that