Two circular wooden pulley sheaves. It is not clear whether these wooden pulley sheaves were a pair or from single sheave pulleys. Generally made from ash (Fraxinus), hickory (Carya) in the case of North America, or Lignum vitae. Lignum vitae, Latin for 'wood of life', is a trade wood, also called Guayacan or Guaiacum from the trees of the genus Guaiacum. The trees are indigenous to the Caribbean and the northern coast of South America and have been an important export crop to Europe since the beginning of the 16th century due to its extraordinary combination of strength, toughness, and density. It was also considered to have self lubricating properties. Ash though tough and elastic is prone to wet rot. Roller bushes were also introduced during the 1880s to reduce friction on the sheave pin. A sheave's size depended mostly on the rope it handled, the higher up the rigging the block was, and the lighter the ropes, the smaller they were. Sheaves also shrank in size as rope quality improved over time, and the introduction of iron parts also contributed to this process. However, many ships continued to use larger blocks due to their making the work easier and therefore requiring less crew to operate. Two circular wooden pulley sheaves. It is not clear whether these wooden pulley sheaves were a pair or from single sheave pulleys. Generally made from ash (Fraxinus), hickory (Carya) in the case of North America, or Lignum vitae. Lignum vitae, Latin for 'wood of life', is a trade wood, also called Guayacan or Guaiacum from the trees of the genus Guaiacum. The trees are indigenous to the Caribbean and the northern coast of South America and have been an important export crop to Europe since the beginning of the 16th century due to its extraordinary combination of strength, toughness, and density. It was also considered to have self lubricating properties. Ash though tough and elastic is prone to wet rot. Roller bushes were also introduced during the 1880s to reduce friction on the sheave pin. A sheave's size depended mostly on the rope it handled, the higher up the rigging the block was, and the lighter the ropes, the smaller they were. Sheaves also shrank in size as rope quality improved over time, and the introduction of iron parts also contributed to this process. However, many ships continued to use larger blocks due to their making the work easier and therefore requiring less crew to operate. This item was found along with a wooden belaying pin (MAS-D100032) and a marble tile (MAS-D100050). A RDF representation of MAS-D100049 2017-03-14T07:28:01+00:00 2017-09-26T13:21:53+01:00 MAS-D100049 MAS-D100049 GB en-GB The Trustees of the British Museum The Trustees of the British Museum 1 The period from for the object http://purl.org/NET/Claros/vocab#Thumbnail Attribute as courtesy of the British Museum A thumbnail image of MAS-D100049 With finder MAS Created by MAS A BB A BB Identified by A BB V L Identified by V L Wood Primary material of object Uncertain By Attribution 3.0 Attribute as courtesy of the British Museum A full resolution image of MAS-D100049 Classification of object