Halberd the 16th through 18th centuries. In the British army, sergeants continued to carry halberds until 1793, when they were replaced by pikes with cross bars. The 18th century halberd had, however, become simply a symbol of rank with no sharpened edge and insufficient strength to use as a weapon. It served as an instrument for ensuring that infantrymen in ranks stood correctly aligned with each other and that their muskets were aimed at the correct level. Halberd A halberd (also called halbard, halbert or Swiss voulge) is a two-handed pole weapon that came to prominent use during the 14th and
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